Tag: Robert Kehoe

Solving the dark energy mystery: A new sky survey assignment for a 45-year-old telescope

Post author By Margaret Allen
Post date February 16, 2018

SMU and other members of a scientific consortium prepare for installation of the Dark Energy Spectroscopic Instrument to survey the night sky from a mile-high mountain peak in Arizona

As part of a large scientific consortium studying dark energy, SMU physicists are on course to help create the largest 3-D map of the universe ever made.

The map will emerge from data gathered by the Dark Energy Spectroscopic Instrument (DESI) being installed on the Nicholas U. Mayall Telescope atop a mountain in Arizona.

The map could help solve the mystery of dark energy, which is driving the accelerating expansion of the universe.

DESI will capture about 10 times more data than a predecessor survey of space using an array of 5,000 swiveling robots. Each robot will be carefully choreographed to point a fiber-optic cable at a preprogrammed sequence of deep-space objects, including millions of galaxies and quasars, which are galaxies that harbor massive, actively feeding black holes.

“DESI will provide the first precise measures of the expansion history of the universe covering approximately the last 10 billion years,” said SMU physicist Robert Kehoe, a professor in the SMU Department of Physics. “This is most of the 13 billion year age of the universe, and it encompasses a critical period in which the universe went from being matter-dominated to dark-energy dominated.”

The universe was expanding, but at a slowing pace, until a few billion years ago, Kehoe said.

“Then the expansion started accelerating,” he said. “The unknown ‘dark energy’ driving that acceleration is now dominating the universe. Seeing this transition clearly will provide a critical test of ideas of what this dark energy is, and how it may tie into theories of gravitation and other fundamental forces.”

The Mayall telescope was originally commissioned 45 years ago to survey the night sky and record observations on glass photographic plates. The telescope is tucked inside a 14-story, 500-ton dome atop a mile-high peak at the National Science Foundation’s Kitt Peak National Observatory – part of the National Optical Astronomy Observatory.

SMU researchers have conducted observing with the Mayall. Decommissioning of that telescope allows for building DESI in it’s place, as well as reusing some parts of the telescope and adding major new sytems. As part of DESI, SMU is involved in development of software for operation of the experiment, as well as for data simulation to aid data anlysis.

“We are also involved in studying the ways in which observational effects impact the cosmology measurements DESI is pursuing,” Kehoe said. SMU graduate students Govinda Dhungana and Ryan Staten also work on DESI. A new addition to the SMU DESI team, post-doctoral researcher Sarah Eftekharzadeh, is working on the SMU software and has studied the same kinds of galaxies
DESI will be measuring.

Now the dome is closing on the previous science chapters of the 4-meter Mayall Telescope so that it can prepare for its new role in creating the 3-D map.

The temporary closure sets in motion the largest overhaul in the telescope’s history and sets the stage for the installation of the Dark Energy Spectroscopic Instrument, which will begin a five-year observing run next year.

“This day marks an enormous milestone for us,” said DESI Director Michael Levi of the Department of Energy’s Lawrence Berkeley National Laboratory , which leads the project’s international collaboration. “Now we remove the old equipment and start the yearlong process of putting the new stuff on.”

More than 465 researchers from about 71 institutions are participating in the DESI collaboration.

The entire top end of the telescope, which weighs as much as a school bus and houses the telescope’s secondary mirror and a large digital camera, will be removed and replaced with DESI instruments. A large crane will lift the telescope’s top end through the observing slit in its dome.

Besides providing new insights about the universe’s expansion and large-scale structure, DESI will also help to set limits on theories related to gravity and the formative stages of the universe, and could even provide new mass measurements for a variety of elusive yet abundant subatomic particles called neutrinos.

“One of the primary ways that we learn about the unseen universe is by its subtle effects on the clustering of galaxies,” said DESI collaboration co-spokesperson Daniel Eisenstein of Harvard University. “The new maps from DESI will provide an exquisite new level of sensitivity in our study of cosmology.”

Mayall’s sturdy construction is perfect platform for new 9-ton instrument
The Mayall Telescope has played an important role in many astronomical discoveries, including measurements supporting the discovery of dark energy and establishing the role of dark matter in the universe from measurements of galaxy rotation. Its observations have also been used in determining the scale and structure of the universe. Dark matter and dark energy together are believed to make up about 95 percent of all of the universe’s mass and energy.

It was one of the world’s largest optical telescopes at the time it was built, and because of its sturdy construction it is perfectly suited to carry the new 9-ton instrument.

“We started this project by surveying large telescopes to find one that had a suitable mirror and wouldn’t collapse under the weight of such a massive instrument,” said Berkeley Lab’s David Schlegel, a DESI project scientist.

Arjun Dey, the NOAO project scientist for DESI, explained, “The Mayall was precociously engineered like a battleship and designed with a wide field of view.”

The expansion of the telescope’s field-of-view will allow DESI to map out about one-third of the sky.

DESI will transform the speed of science with automated preprogrammed robots
Brenna Flaugher, a DESI project scientist who leads the astrophysics department at Fermi National Accelerator Laboratory, said DESI will transform the speed of science at the Mayall Telescope.

“The telescope was designed to carry a person at the top who aimed and steered it, but with DESI it’s all automated,” she said. “Instead of one at a time we can measure the velocities of 5,000 galaxies at a time – we will measure more than 30 million of them in our five-year survey.”

DESI will use an array of 5,000 swiveling robots, each carefully choreographed to point a fiber-optic cable at a preprogrammed sequence of deep-space objects, including millions of galaxies and quasars, which are galaxies that harbor massive, actively feeding black holes.

The fiber-optic cables will carry the light from these objects to 10 spectrographs, which are tools that will measure the properties of this light and help to pinpoint the objects’ distance and the rate at which they are moving away from us. DESI’s observations will provide a deep look into the early universe, up to about 11 billion years ago.

DESI will capture about 10 times more data than a predecessor survey
The cylindrical, fiber-toting robots, which will be embedded in a rounded metal unit called a focal plate, will reposition to capture a new exposure of the sky roughly every 20 minutes. The focal plane assembly, which is now being assembled at Berkeley Lab, is expected to be completed and delivered to Kitt Peak this year.

DESI will scan one-third of the sky and will capture about 10 times more data than a predecessor survey, the Baryon Oscillation Spectroscopic Survey (BOSS). That project relied on a manually rotated sequence of metal plates – with fibers plugged by hand into pre-drilled holes – to target objects.

All of DESI’s six lenses, each about a meter in diameter, are complete. They will be carefully stacked and aligned in a steel support structure and will ultimately ride with the focal plane atop the telescope.

Each of these lenses took shape from large blocks of glass. They have criss-crossed the globe to receive various treatments, including grinding, polishing, and coatings. It took about 3.5 years to produce each of the lenses, which now reside at University College London in the U.K. and will be shipped to the DESI site this spring.

Precise measurements of millions of galaxies will reveal effects of dark energy
The Mayall Telescope has most recently been enlisted in a DESI-supporting sky survey known as the Mayall z-Band Legacy Survey, which is one of four sky surveys that DESI will use to preselect its targeted sky objects. SMU astrophysicists carried out observing duties on that survey, which wrapped up just days ago on Feb. 11, to support the coming DESI scientific results.

Data from these surveys are analyzed at Berkeley Lab’s National Energy Research Scientific Computing Center, a DOE Office of Science User Facility. Data from these surveys have been released to the public at http://legacysurvey.org.

“We can see about a billion galaxies in the survey images, which is quite a bit of fun to explore,” Schlegel said. “The DESI instrument will precisely measure millions of those galaxies to see the effects of dark energy.” 

Levi noted that there is already a lot of computing work underway at the Berkeley computing center to prepare for the stream of data that will pour out of DESI once it starts up.

“This project is all about generating huge quantities of data,” Levi said. “The data will go directly from the telescope to the Berkeley computing center for processing. We will create hundreds of universes in these computers and see which universe best fits our data.”

Installation of DESI’s components is expected to begin soon and to wrap up in April 2019, with first science observations planned in September 2019.

“Installing DESI on the Mayall will put the telescope at the heart of the next decade of discoveries in cosmology,” said Risa Wechsler, DESI collaboration co-spokesperson and associate professor of physics and astrophysics at SLAC National Accelerator Laboratory and Stanford University. “The amazing 3-D map it will measure may solve some of the biggest outstanding questions in cosmology, or surprise us and bring up new ones.” — Berkeley Lab and SMU

Tags Dark Energy Spectroscopic Instrument, Dedman College, DESI, Govinda Dhungana, Robert Kehoe, Ryan Staten, Sarah Eftekharzadeh, SMU Department of Physics

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KDFW Fox 4: NASA discovers seven earth-like planets relatively near

Post author By Margaret Allen
Post date February 24, 2017
No Comments on KDFW Fox 4: NASA discovers seven earth-like planets relatively near

A “major step forward” toward the goal of answering the very big question: Is there life on other worlds?

DFW Fox 4 TV reporter Steve Eagar expressed “nerd-level” excitement about NASA’s announcement Feb. 22 of the discovery of seven new Earth-like planets. Eagar interviewed SMU professor Robert Kehoe, who leads the SMU astronomy team from the Department of Physics.

NASA announced that the Spitzer Space Telescope has revealed the first known system of seven Earth-size planets around a single star. Three of these planets are firmly located in an area called the habitable zone, where liquid water is most likely to exist on a rocky planet.

“This is a surprising jump in our ability to understand earth like planets,” Kehoe told Eagar.

Kehoe and the SMU astronomy team recently reported discovery of a rare star as big — or bigger — than the Earth’s sun that is expanding and contracting in a unique pattern in three different directions.

The star is one that pulsates and so is characterized by varying brightness over time. It’s situated 7,000 light years away from the Earth in the constellation Pegasus. Called a variable star, this particular star is one of only seven known stars of its kind in our Milky Way galaxy.

Watch the video interview on Fox 4.

Tags Dedman College, Robert Kehoe, SMU Department of Physics

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Astronomy: High school students identify an ultra-rare star

Post author By Margaret Allen
Post date February 20, 2017
No Comments on Astronomy: High school students identify an ultra-rare star

This newly-discovered variable is one of only seven of its kind known in our galaxy.

Science journalist Alison Klesman with the online science news magazine Astronomy covered the discovery of a variable star by SMU professor Robert Kehoe and the astronomy team in the SMU Department of Physics.

A high school student in an SMU summer astronomy program made the initial discovery upon culling through archived star observation data recorded by the small but powerful ROTSE-I telescope formerly at Los Alamos National Laboratory in New Mexico.

Other authors on the study were SMU research astronomer Farley Ferrante, a member of the team, Plano Senior High School student Derek Horning, who first discovered the object in the ROTSE-I data, and Eric Guzman, a physics graduate from the University of Texas at Dallas who is entering SMU’s graduate program and who identified the star as pulsating.

The newest delta Scuti (SKOO-tee) star in our night sky is so rare it’s only one of seven identified by astronomers in the Milky Way. Discovered at SMU, the star — like our sun — is in the throes of stellar evolution, to conclude as a dying ember in millions of years. Until then, the exceptional star pulsates brightly, expanding and contracting from heating and cooling of hydrogen burning at its core.

The Astronomy article, “High school students identify an ultra-rare star,” published Feb. 15, 2017.

Read the full story.

EXCERPT:

By Alison Klesman
Astronomy
The stars shining in the night sky might seem steady and reliable, but in truth, they are constantly changing and evolving. Out of the 100 billion or so stars that inhabit the Milky Way, a little more than 400,900 are classified as variable, meaning they change in brightness over time.

Of those hundreds of thousands of variables catalogued in our galaxy, however, only seven belong to a class called Triple Mode high amplitude delta Scuti, or HADS(B), stars — and that seventh was just recently discovered by a high school student during a summer astronomy program at Southern Methodist University in Dallas.

The star, roughly the size of our Sun or possibly larger, is about 7,000 light-years away in the constellation Pegasus. It currently has only a catalog name: ROTSE1 J232056.45+345150.9. The name comes in part from the telescope used to discover it, the ROTSE-I telescope at Los Alamos National Laboratory in New Mexico.

While examining data from the telescope taken in September of 2000, Plano Senior High School student Derek Hornung noticed the star’s strange light curve, which shows the star’s brightness over time. A non-variable star’s light curve is simply a straight line, unchanging as the hours, days, and months go by. But a variable star exhibits periodic changes in brightness over the course of hours or days, creating a recognizable repeating pattern. Variable stars are classified by the patterns their light curves make, and named after the first star of each type discovered. Delta Scuti variables are thus named after the star delta Scuti.

But there’s more to this story, still. The star is not only a delta Scuti variable, of which there are thousands known, but it is also a rare type within the delta Scuti class, a HADS(B) star. HADS(B) stars show asymmetric light curves that change brightness quickly over time. These stars are pulsating in two modes, which means the star is expanding in two directions at once. There are only 114 HADS(B) stars currently known. Rarer still are Triple Mode HADS(B) stars, of which there were only six previously identified in the Milky way. Triple Mode HADS(B) stars pulsate in not two, but three directions at once. For ROTSE1 J232056.45+345150.9, this process repeats itself every 2.5 hours.

Read the full story.

Tags Dedman College, Farley Ferrante, Robert Kehoe, SMU Department of Physics

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New delta Scuti: Rare pulsating star 7,000 light years away is 1 of only 7 in Milky Way

Post author By Margaret Allen
Post date February 13, 2017

A star — as big as or bigger than our sun — in the Pegasus constellation is expanding and contracting in three different directions simultaneously on a scale of once every 2.5 hours, the result of heating and cooling of hydrogen fuel burning 28 million degrees Fahrenheit at its core

The newest delta Scuti (SKOO-tee) star in our night sky is so rare it’s only one of seven identified by astronomers in the Milky Way. Discovered at Southern Methodist University in Dallas, the star — like our sun — is in the throes of stellar evolution, to conclude as a dying ember in millions of years. Until then, the exceptional star pulsates brightly, expanding and contracting from heating and cooling of hydrogen burning at its core.

Astronomers are reporting a rare star as big — or bigger — than the Earth’s sun that is expanding and contracting in a unique pattern in three different directions.

The star is one that pulsates and so is characterized by varying brightness over time. It’s situated 7,000 light years away from the Earth in the constellation Pegasus, said astronomer Farley Ferrante, a member of the team that made the discovery at Southern Methodist University, Dallas.

Called a variable star, this particular star is one of only seven known stars of its kind in our Milky Way galaxy.

“It was challenging to identify it,” Ferrante said. “This is the first time we’d encountered this rare type.”

The Milky Way has more than 100 billion stars. But just over 400,900 are catalogued as variable stars. Of those, a mere seven — including the one identified at SMU — are the rare intrinsic variable star called a Triple Mode ‘high amplitude delta Scuti’ (pronounced SKOO-tee) or Triple Mode HADS(B), for short.

“The discovery of this object helps to flesh out the characteristics of this unique type of variable star. These and further measurements can be used to probe the way the pulsations happen,” said SMU’s Robert Kehoe, a professor in the Department of Physics who leads the SMU astronomy team. “Pulsating stars have also been important to improving our understanding of the expansion of the universe and its origins, which is another exciting piece of this puzzle.”

The star doesn’t yet have a common name, only an official designation based on the telescope that recorded it and its celestial coordinates. The star can be observed through a telescope, but identifying it was much more complicated.

Upon verification, the star was logged into the International Variable Star Index as ROTSE1 J232056.45+345150.9 by the American Association of Variable Star Observers at this link.

How in the universe was it discovered?
SMU’s astrophysicists discovered the variable star by analyzing light curve shape, a key identifier of star type. Light curves were created from archived data procured by ROTSE-I during multiple nights in September 2000. The telescope generates images of optical light from electrical signals based on the intensity of the source. Data representing light intensity versus time is plotted on a scale to create the light curves.

Plano Senior High School student Derek Hornung first discovered the object in the ROTSE-I data and prepared the initial light curves. From the light curves, the astronomers knew they had something special.

It became even more challenging to determine the specific kind of variable star. Then Eric Guzman, a physics graduate from the University of Texas at Dallas, who is entering SMU’s graduate program, solved the puzzle, identifying the star as pulsating.

“Light curve patterns are well established, and these standard shapes correspond to different types of stars,” Ferrante said. “In a particular field of the night sky under observation there may have been hundreds or even thousands of stars. So the software we use generates a light curve for each one, for one night. Then — and here’s the human part — we use our brain’s capacity for pattern recognition to find something that looks interesting and that has a variation. This allows the initial variable star candidate to be identified. From there, you look at data from several other nights. We combine all of those into one plot, as well as add data sets from other telescopes, and that’s the evidence for discerning what kind of variable star it is.”

That was accomplished conclusively during the referee process with the Variable Star Index moderator.

The work to discover and analyze this rare variable star was carried out in conjunction with analyses by eight other high school students and two other undergraduates working on other variable candidates. The high school students were supported by SMU’s chapter of the Department of Energy/National Science Foundation QuarkNet program.

Heating and cooling, expanding and contracting
Of the stars that vary in brightness intrinsically, a large number exhibit amazingly regular oscillations in their brightness which is a sign of some pulsation phenomenon in the star, Ferrante said.

Pulsation results from expanding and contracting as the star ages and exhausts the hydrogen fuel at its core. As the hydrogen fuel burns hotter, the star expands, then cools, then gravity shrinks it back, and contraction heats it back up.

“I’m speaking very generally, because there’s a lot of nuance, but there’s this continual struggle between thermal expansion and gravitational contraction,” Ferrante said. “The star oscillates like a spring, but it always overshoots its equilibrium, doing that for many millions of years until it evolves into the next phase, where it burns helium in its core. And if it’s about the size and mass of the sun — then helium fusion and carbon is the end stage. And when helium is used up, we’re left with a dying ember called a white dwarf.”

Within the pulsating category is a class of stars called delta Scuti, of which there are thousands. They are named for a prototype star whose characteristic features — including short periods of pulsating on the scale of a few hours — are typical of the entire class.

Within delta Scuti is a subtype of which hundreds have been identified, called high amplitude delta Scuti, or HADS. Their brightness varies to a particularly large degree, registering more than 10 percent difference between their minimum and maximum brightness, indicating larger pulsations.

Common delta Scuti pulsate along the radius in a uniform contraction like blowing up a balloon. A smaller sub-category are the HADS, which show asymmetrical-like pulsating curves.

Within HADS, there’s the relatively rare subtype called HADS(B) , of which there are only 114 identified.

Star evolution — just a matter of time
A HADS(B) is distinguished by its two modes of oscillation — different parts of the star expanding at different rates in different directions but the ratio of those two periods is always the same.

For the SMU star, two modes of oscillation weren’t immediately obvious in its light curve.

“But we knew there was something going on because the light curve didn’t quite match known light curves of other delta Scuti’s and HADS’ objects we had studied. The light curves — when laid on top of each other — presented an asymmetry,” Ferrante said. “Ultimately the HADS(B) we discovered is even more unique than that though — it’s a Triple Mode HADS(B) and there were previously only six identified in the Milky Way. So it has three modes of oscillation, all three with a distinct period, overlapping, and happening simultaneously.”

So rare, in fact, there’s no name yet for this new category nor a separate registry designation for it. Guzman, the student researcher who analyzed and categorized the object, recalled how the mystery unfolded.

“When I began the analysis of the object, we had an initial idea of what type it could be,” Guzman said. “My task was to take the data and try to confirm the type by finding a second period that matched a known constant period ratio. After successfully finding the second mode, I noticed a third signal. After checking the results, I discovered the third signal coincided with what is predicted of a third pulsation mode.”

The SMU Triple Mode HADS(B) oscillates on a scale of 2.5 hours, so it will expand and contract 10 times in one Earth day. It and the other known six HADS(B)’s are in the same general region of the Milky Way galaxy, within a few thousand light years of one another.

“I’m sure there are more out there,” Ferrante said, “but they’re still rare, a small fraction.”

Red giant the final phase of star’s evolution
SMU’s Triple Mode HADS(B) is unstable and further along in its stellar evolution than our sun, which is about middle-aged and whose pulsating variations occur over a much longer period of time. SMU’s Triple Mode HADS(B) core temperature, heated from the burning of hydrogen fuel, is about 15 million Kelvin or 28 million degrees Fahrenheit.

Someday, millions of years from now, SMU’s Triple Mode HADS(B) will deplete the hydrogen fuel at its core, and expand into a red giant.

“Our sun might eventually experience this as well,” Ferrante said. “But Earth will be inhospitable long before then. We won’t be here to see it.”

Funding was through the Texas Space Grant Consortium, an affiliate of NASA; SMU Dedman College. Department of Energy/National Science Foundation QuarkNet program.

ROTSE-I began operating in late 1997, surveying the sky all night, every clear night of the year for three years. It was decommissioned in 2001 and replaced by ROTSE-III. SMU owns the ROTSE-IIIb telescope at McDonald Observatory, Fort Davis, Texas.

Tags Dedman College, Farley Ferrante, Robert Kehoe, SMU Department of Physics

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SMU physicists: CERN’s Large Hadron Collider is once again smashing protons, taking data

Post author By Margaret Allen
Post date May 9, 2016

CERN’s Large Hadron Collider (LHC) and its experiments are back in action, now taking physics data for 2016 to get an improved understanding of fundamental physics.

Following its annual winter break, the most powerful collider in the world has been switched back on.

Geneva-based CERN’s Large Hadron Collider (LHC) — an accelerator complex and its experiments — has been fine-tuned using low-intensity beams and pilot proton collisions, and now the LHC and the experiments are ready to take an abundance of data.

The goal is to improve our understanding of fundamental physics, which ultimately in decades to come can drive innovation and inventions by researchers in other fields.

Scientists from SMU’s Department of Physics are among the several thousand physicists worldwide who contribute on the LHC research.

“All of us here hope that some of the early hints will be confirmed and an unexpected physics phenomenon will show up,” said Ryszard Stroynowski, SMU professor and a principal investigator on the LHC. “If something new does appear, we will try to contribute to the understanding of what it may be.”

SMU physicists work on the LHC’s ATLAS experiment. Run 1 of the Large Hadron Collider made headlines in 2012 when scientists observed in the data a new fundamental particle, the Higgs boson. The collider was then paused for an extensive upgrade and came back much more powerful than before. As part of Run 2, physicists on the Large Hadron Collider’s experiments are analyzing new proton collision data to unravel the structure of the Higgs.

The Higgs was the last piece of the puzzle for the Standard Model — a theory that offers the best description of the known fundamental particles and the forces that govern them. In 2016 the ATLAS and CMS collaborations of the LHC will study this boson in depth.

Over the next three to four months there is a need to verify the measurements of the Higgs properties taken in 2015 at lower energies with less data, Stroynowski said.

“We also must check all hints of possible deviations from the Standard Model seen in the earlier data — whether they were real effects or just statistical fluctuations,” he said. “In the long term, over the next one to two years, we’ll pursue studies of the Higgs decays to heavy b quarks leading to the understanding of how one Higgs particle interacts with other Higgs particles.”

In addition, the connection between the Higgs Boson and the bottom quark is an important relationship that is well-described in the Standard Model but poorly understood by experiments, said Stephen Sekula, SMU associate professor. The SMU ATLAS group will continue work started last year to study the connection, Sekula said.

“We will be focused on measuring this relationship in both Standard Model and Beyond-the-Standard Model contexts,” he said.

SMU physicists also study Higgs-boson interactions with the most massive known particle, the top-quark, said Robert Kehoe, SMU associate professor.

“This interaction is also not well-understood,” Kehoe said. “Our group continues to focus on the first direct measurement of the strength of this interaction, which may reveal whether the Higgs mechanism of the Standard Model is truly fundamental.”

All those measurements are key goals in the ATLAS Run 2 and beyond physics program, Sekula said. In addition, none of the ultimate physics goals can be achieved without faultless operation of the complex ATLAS detector, its software and data acquisition system.

“The SMU group maintains work on operations, improvements and maintenance of two components of ATLAS — the Liquid Argon Calorimeter and data acquisition trigger,” Stroynowski said.

Intensity of the beam to increase, supplying six times more proton collisions
Following a short commissioning period, the LHC operators will now increase the intensity of the beams so that the machine produces a larger number of collisions.

“The LHC is running extremely well,” said CERN Director for Accelerators and Technology, Frédérick Bordry. “We now have an ambitious goal for 2016, as we plan to deliver around six times more data than in 2015.”

The LHC’s collisions produce subatomic fireballs of energy, which morph into the fundamental building blocks of matter. The four particle detectors located on the LHC’s ring allow scientists to record and study the properties of these building blocks and look for new fundamental particles and forces.

This is the second year the LHC will run at a collision energy of 13 TeV. During the first phase of Run 2 in 2015, operators mastered steering the accelerator at this new higher energy by gradually increasing the intensity of the beams.

“The restart of the LHC always brings with it great emotion”, said Fabiola Gianotti, CERN Director General. “With the 2016 data the experiments will be able to perform improved measurements of the Higgs boson and other known particles and phenomena, and look for new physics with an increased discovery potential.”

New exploration can begin at higher energy, with much more data
Beams are made of “trains” of bunches, each containing around 100 billion protons, moving at almost the speed of light around the 27-kilometre ring of the LHC. These bunch trains circulate in opposite directions and cross each other at the center of experiments. Last year, operators increased the number of proton bunches up to 2,244 per beam, spaced at intervals of 25 nanoseconds. These enabled the ATLAS and CMS collaborations to study data from about 400 million million proton–proton collisions. In 2016 operators will increase the number of particles circulating in the machine and the squeezing of the beams in the collision regions. The LHC will generate up to 1 billion collisions per second in the experiments.

“In 2015 we opened the doors to a completely new landscape with unprecedented energy. Now we can begin to explore this landscape in depth,” said CERN Director for Research and Computing Eckhard Elsen.

Between 2010 and 2013 the LHC produced proton-proton collisions with 8 Tera-electronvolts of energy. In the spring of 2015, after a two-year shutdown, LHC operators ramped up the collision energy to 13 TeV. This increase in energy enables scientists to explore a new realm of physics that was previously inaccessible. Run II collisions also produce Higgs bosons — the groundbreaking particle discovered in LHC Run I — 25 percent faster than Run I collisions and increase the chances of finding new massive particles by more than 40 percent.

But there are still several questions that remain unanswered by the Standard Model, such as why nature prefers matter to antimatter, and what dark matter consists of, despite it potentially making up one quarter of our universe.

The huge amounts of data from the 2016 LHC run will enable physicists to challenge these and many other questions, to probe the Standard Model further and to possibly find clues about the physics that lies beyond it.

The physics run with protons will last six months. The machine will then be set up for a four-week run colliding protons with lead ions.

“We’re proud to support more than a thousand U.S. scientists and engineers who play integral parts in operating the detectors, analyzing the data, and developing tools and technologies to upgrade the LHC’s performance in this international endeavor,” said Jim Siegrist, Associate Director of Science for High Energy Physics in the U.S. Department of Energy’s Office of Science. “The LHC is the only place in the world where this kind of research can be performed, and we are a fully committed partner on the LHC experiments and the future development of the collider itself.”

The four largest LHC experimental collaborations, ALICE, ATLAS, CMS and LHCb, now start to collect and analyze the 2016 data. Their broad physics program will be complemented by the measurements of three smaller experiments — TOTEM, LHCf and MoEDAL — which focus with enhanced sensitivity on specific features of proton collisions. — SMU, CERN and Fermilab

Tags Dedman College, Jingbo Ye, Robert Kehoe, Ryszard Stroynowski, SMU Department of Physics, Stephen J. Sekula

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Nearby massive star explosion 30 million years ago equaled brightness of 100 million suns

Post author By Margaret Allen
Post date April 26, 2016

Analysis of exploding star’s light curve and color spectrum reveal spectacular demise of one of the closest supernova to Earth in recent years; its parent star was so big it’s radius was 200 times larger than our sun

A giant star that exploded 30 million years ago in a galaxy near Earth had a radius prior to going supernova that was 200 times larger than our sun, according to astrophysicists at Southern Methodist University, Dallas.

The sudden blast hurled material outward from the star at a speed of 10,000 kilometers a second. That’s equivalent to 36 million kilometers an hour or 22.4 million miles an hour, said SMU physicist Govinda Dhungana, lead author on the new analysis.

The comprehensive analysis of the exploding star’s light curve and color spectrum have revealed new information about the existence and sudden death of supernovae in general, many aspects of which have long baffled scientists.

“There are so many characteristics we can derive from the early data,” Dhungana said. “This was a big massive star, burning tremendous fuel. When it finally reached a point its core couldn’t support the gravitational pull inward, suddenly it collapsed and then exploded.”

The massive explosion was one of the closest to Earth in recent years, visible as a point of light in the night sky starting July 24, 2013, said Robert Kehoe, SMU physics professor, who leads SMU’s astrophysics team.

The explosion, termed by astronomers Supernova 2013ej, in a galaxy near our Milky Way was equal in energy output to the simultaneous brightness of 100 million of the Earth’s suns.

The star was one of billions in the spiral galaxy M74 in the constellation Pisces.

Considered close by supernova standards, SN 2013ej was in fact so far away that light from the explosion took 30 million years to reach Earth. At that distance, even such a large explosion was only visible by telescopes.

Dhungana and colleagues were able to explore SN 2013ej via a rare collection of extensive data from seven ground-based telescopes and NASA’s Swift satellite.

The data span a time period prior to appearance of the supernova in July 2013 until more than 450 days after.

The team measured the supernova’s evolving temperature, its mass, its radius, the abundance of a variety of chemical elements in its explosion and debris and its distance from Earth. They also estimated the time of the shock breakout, the bright flash from the shockwave of the explosion.

The star’s original mass was about 15 times that of our sun, Dhungana said. Its temperature was a hot 12,000 Kelvin (approximately 22,000 degrees Fahrenheit) on the tenth day after the explosion, steadily cooling until it reached 4,500 Kelvin after 50 days. The sun’s surface is 5,800 Kelvin, while the Earth’s core is estimated to be about 6,000 Kelvin.

The new measurements are published online here in the May 2016 issue of The Astrophysical Journal, “Extensive spectroscopy and photometry of the Type IIP Supernova 2013j.”

Shedding new light on supernovae, mysterious objects of our universe
Supernovae occur throughout the universe, but they are not fully understood. Scientists don’t directly observe the explosions but instead detect changes in emerging light as material is hurled from the exploding star in the seconds and days after the blast.

Telescopes such as SMU’s robotic ROTSE-IIIb telescope at McDonald Observatory in Texas, watch our sky and pick up the light as a point of brightening light. Others, such as the Hobby Eberly telescope, also at McDonald, observe a spectrum.

SN 2013ej is M74’s third supernova in just 10 years. That is quite frequent compared to our Milky Way, which has had a scant one supernova observed over the past 400 years. NASA estimates that the M74 galaxy consists of 100 billion stars.

M74 is one of only a few dozen galaxies first cataloged by the astronomer Charles Messier in the late 1700s. It has a spiral structure — also the Milky Way’s apparent shape — indicating it is still undergoing star formation, as opposed to being an elliptical galaxy in which new stars no longer form.

It’s possible that planets were orbiting SN 2013ej’s progenitor star prior to it going supernova, in which case those objects would have been obliterated by the blast, Kehoe said.

“If you were nearby, you wouldn’t know there was a problem beforehand, because at the surface you can’t see the core heating up and collapsing,” Kehoe said. “Then suddenly it explodes — and you’re toast.”

Distances to nearby galaxies help determine cosmic distance ladder
Scientists remain unsure whether supernovae leave behind a black hole or a neutron star like a giant atomic nucleus the size of a city.

“The core collapse and how it produces the explosion is particularly tricky,” Kehoe said. “Part of what makes SN 2013ej so interesting is that astronomers are able to compare a variety of models to better understand what is happening. Using some of this information, we are also able to calculate the distance to this object. This allows us a new type of object with which to study the larger universe, and maybe someday dark energy.”

Being 30 million light years away, SN 2013ej was a relatively nearby extragalactic event, according to Jozsef Vinko, astrophysicist at Konkoly Observatory and University of Szeged in Hungary.

“Distances to nearby galaxies play a significant role in establishing the so-called cosmic distance ladder, where each rung is a galaxy at a known distance.”

Vinko provided important data from telescopes at Konkoly Observatory and Hungary’s Baja Observatory and carried out distance measurement analysis on SN 2013ej.

“Nearby supernovae are especially important,” Vinko said. “Paradoxically, we know the distances to the nearest galaxies less certainly than to the more distant ones. In this particular case we were able to combine the extensive datasets of SN 2013ej with those of another supernova, SN 2002ap, both of which occurred in M74, to suppress the uncertainty of their common distance derived from those data.”

Supernova spectrum analysis is like taking a core sample
While stars appear to be static objects that exist indefinitely, in reality they are primarily a burning ball, fueled by the fusion of elements, including hydrogen and helium into heavier elements. As they exhaust lighter elements, they must contract in the core and heat up to burn heavier elements. Over time, they fuse the various chemical elements of the periodic table, proceeding from lightest to heaviest. Initially they fuse helium into carbon, nitrogen and oxygen. Those elements then fuel the fusion of progressively heavier elements such as sulfur, argon, chlorine and potassium.

“Studying the spectrum of a supernova over time is like taking a core sample,” Kehoe said. “The calcium in our bones, for example, was cooked in a star. A star’s nuclear fusion is always forging heavier and heavier elements. At the beginning of the universe there was only hydrogen and helium. The other elements were made in stars and in supernovae. The last product to get created is iron, which is an element that is so heavy it can’t be burned as fuel.”

Dhungana’s spectrum analysis of SN 2013ej revealed many elements, including hydrogen, helium, calcium, titanium, barium, sodium and iron.

“When we have as many spectra as we have for this supernova at different times,” Kehoe added, “we are able to look deeper and deeper into the original star, sort of like an X-ray or a CAT scan.”

SN 2013ej’s short-lived existence was just tens of millions of years
Analysis of SN 2013ej’s spectrum from ultraviolet through infrared indicates light from the explosion reached Earth July 23, 2013. It was discovered July 25, 2013 by the Katzman Automatic Imaging Telescope at California’s Lick Observatory. A look back at images captured by SMU’s ROTSE-IIIb showed that SMU’s robotic telescope detected the supernova several hours earlier, Dhungana said.

“These observations were able to show a rapidly brightening supernova that started just 20 hours beforehand,” he said. “The start of the supernova, termed ‘shock breakout,’ corresponds to the moment when the internal explosion crashes through the star’s outer layers.”

Like many others, SN 2013ej was a Type II supernova. That is a massive star still undergoing nuclear fusion. Once iron is fused, the fuel runs out, causing the core to collapse. Within a quarter second the star explodes.

Supernovae have death and birth written all over them
Massive stars typically have a shorter life span than smaller ones.

“SN 2013ej probably lived tens of millions of years,” Kehoe said. “In universe time, that’s the blink of an eye. It’s not very long-lived at all compared to our sun, which will live billions of years. Even though these stars are bigger and have a lot more fuel, they burn it really fast, so they just get hotter and hotter until they just gobble up the matter and burn it.”

For most of its brief life, SN 2013ej would probably have burned hydrogen, which then fused to helium, burning for a few hundred thousand years, then perhaps carbon and oxygen for a few hundred days, calcium for a few months and silicon for several days.

“Supernovae have death and birth written all over them,” Kehoe said. “Not only do they create the elements we are made of, but the shockwave that goes out from the explosion — that’s where our solar system comes from.”

Outflowing material slams into clouds of material in interstellar space, causing it to collapse and form a solar system.

“The heavy elements made in the supernova and its parent star are those which comprise the bulk of terrestrial planets, like Earth, and are necessary for life,” Kehoe said.

Besides physicists in the SMU Department of Physics, researchers on the project also included scientists from the University of Szeged, Szeged, Hungary; the University of Texas, Austin, Texas; Konkoly Observatory, Budapest, Hungary; and the University of California, Berkeley, Calif. — Margaret Allen

SMU has an uplink facility located on campus for live TV, radio, or online interviews. To speak with an SMU expert or book an SMU guest in the studio, call SMU News & Communications at 214-768-7650.

Tags Dedman College, Govinda Dhungana, Robert Kehoe, SMU Department of Physics

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SMU 2015 research efforts broadly noted in a variety of ways for world-changing impact

Post author By Margaret Allen
Post date January 8, 2016

SMU scientists and their research have a global reach that is frequently noted, beyond peer publications and media mentions.

By Margaret Allen
SMU News & Communications
It was a good year for SMU faculty and student research efforts. Here is a small sampling of public and published acknowledgements during 2015:

Hot topic merits open access
Taylor & Francis, publisher of the online journal Environmental Education Research, lifted its subscription-only requirement to meet demand for an article on how climate change is taught to middle-schoolers in California.

Co-author of the research was Diego Román, assistant professor in the Department of Teaching and Learning, Annette Caldwell Simmons School of Education and Human Development.

Román’s research revealed that California textbooks are teaching sixth graders that climate change is a controversial debate stemming from differing opinions, rather than a scientific conclusion based on rigorous scientific evidence.

The article, “Textbooks of doubt: Using systemic functional analysis to explore the framing of climate change in middle-school science textbooks,” published in September. The finding generated such strong interest that Taylor & Francis opened access to the article.

Research makes the cover of Biochemistry
Drugs important in the battle against cancer were tested in a virtual lab by SMU biology professors to see how they would behave in the human cell.

A computer-generated composite image of the simulation made the Dec. 15 cover of the journal Biochemistry.

Scientific articles about discoveries from the simulation were also published in the peer review journals Biochemistry and in Pharmacology Research & Perspectives.

The researchers tested the drugs by simulating their interaction in a computer-generated model of one of the cell’s key molecular pumps — the protein P-glycoprotein, or P-gp. Outcomes of interest were then tested in the Wise-Vogel wet lab.

The ongoing research is the work of biochemists John Wise, associate professor, and Pia Vogel, professor and director of the SMU Center for Drug Discovery, Design and Delivery in Dedman College. Assisting them were a team of SMU graduate and undergraduate students.

The researchers developed the model to overcome the problem of relying on traditional static images for the structure of P-gp. The simulation makes it possible for researchers to dock nearly any drug in the protein and see how it behaves, then test those of interest in an actual lab.

To date, the researchers have run millions of compounds through the pump and have discovered some that are promising for development into pharmaceutical drugs to battle cancer.

Click here to read more about the research.

SMU, Simpson Rowe, sexual assault, video

Strong interest in research on sexual victimization
Teen girls were less likely to report being sexually victimized after learning to assertively resist unwanted sexual overtures and after practicing resistance in a realistic virtual environment, according to three professors from the SMU Department of Psychology.

The finding was reported in Behavior Therapy. The article was one of the psychology journal’s most heavily shared and mentioned articles across social media, blogs and news outlets during 2015, the publisher announced.

The study was the work of Dedman College faculty Lorelei Simpson Rowe, associate professor and Psychology Department graduate program co-director; Ernest Jouriles, professor; and Renee McDonald, SMU associate dean for research and academic affairs.

The journal’s publisher, Elsevier, temporarily has lifted its subscription requirement on the article, “Reducing Sexual Victimization Among Adolescent Girls: A Randomized Controlled Pilot Trial of My Voice, My Choice,” and has opened it to free access for three months.

Click here to read more about the research.

Consumers assume bigger price equals better quality
Even when competing firms can credibly disclose the positive attributes of their products to buyers, they may not do so.

Instead, they find it more lucrative to “signal” quality through the prices they charge, typically working on the assumption that shoppers think a high price indicates high quality. The resulting high prices hurt buyers, and may create a case for mandatory disclosure of quality through public policy.

That was a finding of the research of Dedman College’s Santanu Roy, professor, Department of Economics. Roy’s article about the research was published in February in one of the blue-ribbon journals, and the oldest, in the field, The Economic Journal.

Published by the U.K.’s Royal Economic Society, The Economic Journal is one of the founding journals of modern economics. The journal issued a media briefing about the paper, “Competition, Disclosure and Signaling,” typically reserved for academic papers of broad public interest.

Chemistry research group edits special issue
Chemistry professors Dieter Cremer and Elfi Kraka, who lead SMU’s Computational and Theoretical Chemistry Group, were guest editors of a special issue of the prestigious Journal of Physical Chemistry. The issue published in March.

The Computational and Theoretical research group, called CATCO for short, is a union of computational and theoretical chemistry scientists at SMU. Their focus is research in computational chemistry, educating and training graduate and undergraduate students, disseminating and explaining results of their research to the broader public, and programming computers for the calculation of molecules and molecular aggregates.

The special issue of Physical Chemistry included 40 contributions from participants of a four-day conference in Dallas in March 2014 that was hosted by CATCO. The 25th Austin Symposium drew 108 participants from 22 different countries who, combined, presented eight plenary talks, 60 lectures and about 40 posters.

CATCO presented its research with contributions from Cremer and Kraka, as well as Marek Freindorf, research assistant professor; Wenli Zou, visiting professor; Robert Kalescky, post-doctoral fellow; and graduate students Alan Humason, Thomas Sexton, Dani Setlawan and Vytor Oliveira.

There have been more than 75 graduate students and research associates working in the CATCO group, which originally was formed at the University of Cologne, Germany, before moving to SMU in 2009.

Vertebrate paleontology recognized with proclamation
Dallas Mayor Mike Rawlings proclaimed Oct. 11-17, 2015 Vertebrate Paleontology week in Dallas on behalf of the Dallas City Council.

The proclamation honored the 75th Annual Meeting of the Society of Vertebrate Paleontology, which was jointly hosted by SMU’s Roy M. Huffington Department of Earth Sciences in Dedman College and the Perot Museum of Science and Nature. The conference drew to Dallas some 1,200 scientists from around the world.

Making research presentations or presenting research posters were: faculty members Bonnie Jacobs, Louis Jacobs, Michael Polcyn, Neil Tabor and Dale Winkler; adjunct research assistant professor Alisa Winkler; research staff member Kurt Ferguson; post-doctoral researchers T. Scott Myers and Lauren Michael; and graduate students Matthew Clemens, John Graf, Gary Johnson and Kate Andrzejewski.

The host committee co-chairs were Anthony Fiorillo, adjunct research professor; and Louis Jacobs, professor. Committee members included Polcyn; Christopher Strganac, graduate student; Diana Vineyard, research associate; and research professor Dale Winkler.

KERA radio reporter Kat Chow filed a report from the conference, explaining to listeners the science of vertebrate paleontology, which exposes the past, present and future of life on earth by studying fossils of animals that had backbones.

SMU earthquake scientists rock scientific journal

Modelled pressure changes caused by injection and production. (Nature Communications/SMU)

Findings by the SMU earthquake team reverberated across the nation with publication of their scientific article in the prestigious British interdisciplinary journal Nature, ranked as one of the world’s most cited scientific journals.

The article reported that the SMU-led seismology team found that high volumes of wastewater injection combined with saltwater extraction from natural gas wells is the most likely cause of unusually frequent earthquakes occurring in the Dallas-Fort Worth area near the small community of Azle.

The research was the work of Dedman College faculty Matthew Hornbach, associate professor of geophysics; Heather DeShon, associate professor of geophysics; Brian Stump, SMU Albritton Chair in Earth Sciences; Chris Hayward, research staff and director geophysics research program; and Beatrice Magnani, associate professor of geophysics.

The article, “Causal factors for seismicity near Azle, Texas,” published online in late April. Already the article has been downloaded nearly 6,000 times, and heavily shared on both social and conventional media. The article has achieved a ranking of 270, which puts it in the 99th percentile of 144,972 tracked articles of a similar age in all journals, and 98th percentile of 626 tracked articles of a similar age in Nature.

“It has a very high impact factor for an article of its age,” said Robert Gregory, professor and chair, SMU Earth Sciences Department.

The scientific article also was entered into the record for public hearings both at the Texas Railroad Commission and the Texas House Subcommittee on Seismic Activity.

Researchers settle long-debated heritage question of “The Ancient One”

The skull of Kennewick Man and a sculpted bust by StudioEIS based on forensic facial reconstruction by sculptor Amanda Danning. (Credit: Brittany Tatchell)

The research of Dedman College anthropologist and Henderson-Morrison Professor of Prehistory David Meltzer played a role in settling the long-debated and highly controversial heritage of “Kennewick Man.”

Also known as “The Ancient One,” the 8,400-year-old male skeleton discovered in Washington state has been the subject of debate for nearly two decades. Argument over his ancestry has gained him notoriety in high-profile newspaper and magazine articles, as well as making him the subject of intense scholarly study.

Officially the jurisdiction of the U.S. Army Corps of Engineers, Kennewick Man was discovered in 1996 and radiocarbon dated to 8500 years ago.

Because of his cranial shape and size he was declared not Native American but instead ‘Caucasoid,’ implying a very different population had once been in the Americas, one that was unrelated to contemporary Native Americans.

But Native Americans long have claimed Kennewick Man as theirs and had asked for repatriation of his remains for burial according to their customs.

Meltzer, collaborating with his geneticist colleague Eske Willerslev and his team at the Centre for GeoGenetics at the University of Copenhagen, in June reported the results of their analysis of the DNA of Kennewick in the prestigious British journal Nature in the scientific paper “The ancestry and affiliations of Kennewick Man.”

The results were announced at a news conference, settling the question based on first-ever DNA evidence: Kennewick Man is Native American.

The announcement garnered national and international media attention, and propelled a new push to return the skeleton to a coalition of Columbia Basin tribes. Sen. Patty Murray (D-WA) introduced the Bring the Ancient One Home Act of 2015 and Washington Gov. Jay Inslee has offered state assistance for returning the remains to Native Tribes.

Science named the Kennewick work one of its nine runners-up in the highly esteemed magazine’s annual “Breakthrough of the Year” competition.

The research article has been viewed more than 60,000 times. It has achieved a ranking of 665, which puts it in the 99th percentile of 169,466 tracked articles of a similar age in all journals, and in the 94th percentile of 958 tracked articles of a similar age in Nature.

In “Kennewick Man: coming to closure,” an article in the December issue of Antiquity, a journal of Cambridge University Press, Meltzer noted that the DNA merely confirmed what the tribes had known all along: “We are him, he is us,” said one tribal spokesman. Meltzer concludes: “We presented the DNA evidence. The tribal members gave it meaning.”

Click here to read more about the research.

Prehistoric vacuum cleaner captures singular award

Paleontologists Louis L. Jacobs, SMU, and Anthony Fiorillo, Perot Museum, have identified a new species of marine mammal from bones recovered from Unalaska, an Aleutian island in the North Pacific. (Hillsman Jackson, SMU)

Science writer Laura Geggel with Live Science named a new species of extinct marine mammal identified by two SMU paleontologists among “The 10 Strangest Animal Discoveries of 2015.”

The new species, dubbed a prehistoric hoover by London’s Daily Mail online news site, was identified by SMU paleontologist Louis L. Jacobs, a professor in the Roy M. Huffington Department of Earth Sciences, Dedman College of Humanities and Sciences, and paleontologist and SMU adjunct research professor Anthony Fiorillo, vice president of research and collections and chief curator at the Perot Museum of Nature and Science.

Jacobs and Fiorillo co-authored a study about the identification of new fossils from the oddball creature Desmostylia, discovered in the same waters where the popular “Deadliest Catch” TV show is filmed. The hippo-like creature ate like a vacuum cleaner and is a new genus and species of the only order of marine mammals ever to go extinct — surviving a mere 23 million years.

Desmostylians, every single species combined, lived in an interval between 33 million and 10 million years ago. Their strange columnar teeth and odd style of eating don’t occur in any other animal, Jacobs said.

SMU campus hosted the world’s premier physicists

The SMU Department of Physics hosted the “23rd International Workshop on Deep Inelastic Scattering and Related Subjects” from April 27-May 1, 2015. Deep Inelastic Scattering is the process of probing the quantum particles that make up our universe.

As noted by the CERN Courier — the news magazine of the CERN Laboratory in Geneva, which hosts the Large Hadron Collider, the world’s largest science experiment — more than 250 scientists from 30 countries presented more than 200 talks on a multitude of subjects relevant to experimental and theoretical research. SMU physicists presented at the conference.

The SMU organizing committee was led by Fred Olness, professor and chair of the SMU Department of Physics in Dedman College, who also gave opening and closing remarks at the conference. The committee consisted of other SMU faculty, including Jodi Cooley, associate professor; Simon Dalley, senior lecturer; Robert Kehoe, professor; Pavel Nadolsky, associate professor, who also presented progress on experiments at CERN’s Large Hadron Collider; Randy Scalise, senior lecturer; and Stephen Sekula, associate professor.

Sekula also organized a series of short talks for the public about physics and the big questions that face us as we try to understand our universe.

Click here to read more about the research.

Tags Alan Humason, Alisa J. WInkler, Annette Caldwell Simmons School of Education and Human Development, Anthony Fiorillo, Beatrice Magnani, Bonnie F. Jacobs, Brian W. Stump, Chris Hayward, Christopher Strganac, Dale A. Winkler, Dani Setlawan, David Meltzer, Dedman College, Diana Vineyard, Diego Román, Dieter Creme, Elfi Kraka, Ernest Jouriles, Fredrick Olness, Gary Johnson, Heather R. DeShon, Jodi Cooley, John F. Graf, John Wise, Kate Andrzejewski, Kurt Ferguson, Lauren Michael, Lorelei Simpson Rowe, Louis L. Jacobs, Marek Freindorf, Matthew Clemens, Matthew J. Hornbach, Michael J. Polcyn, Neil Tabor, Pavel Nadolsky, Pia Vogel, Randy Scalise, Renee McDonald, Robert Gregory, Robert Kalescky, Robert Kehoe, Roy M. Huffington Department of Earth Sciences, Santanu Roy, Simon Dalley, SMU Department of Anthropology, SMU Department of Biological Sciences, SMU Department of Chemistry, SMU Department of Economics, SMU Department of Physics, SMU Department of Psychology, Stephen J. Sekula, Thomas Sexton, Timothy S. Myers, Vytor Oliveira, Wenli Zou

Energy & Matter

Top Quark: Precise particle measurement improves subatomic tool probing mysteries of universe

Post author By Margaret Allen
Post date September 28, 2015

In post-Big Bang world, nature’s top quark — a key component of matter — is a highly sensitive probe that physicists use to evaluate competing theories about quantum interactions

Physicists at Southern Methodist University, Dallas, have achieved a new precise measurement of a key subatomic particle, opening the door to better understanding some of the deepest mysteries of our universe.

The researchers calculated the new measurement for a critical characteristic — mass — of the top quark.

Quarks make up the protons and neutrons that comprise almost all visible matter. Physicists have known the top quark’s mass was large, but encountered great difficulty trying to clearly determine it.

The newly calculated measurement of the top quark will help guide physicists in formulating new theories, said Robert Kehoe, a professor in SMU’s Department of Physics. Kehoe leads the SMU group that performed the measurement.

Top quark’s mass matters ultimately because the particle is a highly sensitive probe and key tool to evaluate competing theories about the nature of matter and the fate of the universe.

Physicists for two decades have worked to improve measurement of the top quark’s mass and narrow its value.

“Top” bears on newest fundamental particle, the Higgs boson
The new value from SMU confirms the validity of recent measurements by other physicists, said Kehoe.

But it also adds growing uncertainty about aspects of physics’ Standard Model.

The Standard Model is the collection of theories physicists have derived — and continually revise — to explain the universe and how the tiniest building blocks of our universe interact with one another. Problems with the Standard Model remain to be solved. For example, gravity has not yet been successfully integrated into the framework.

The Standard Model holds that the top quark — known familiarly as “top” — is central in two of the four fundamental forces in our universe — the electroweak force, by which particles gain mass, and the strong force, which governs how quarks interact. The electroweak force governs common phenomena like light, electricity and magnetism. The strong force governs atomic nuclei and their structure, in addition to the particles that quarks comprise, like protons and neutrons in the nucleus.

The top plays a role with the newest fundamental particle in physics, the Higgs boson, in seeing if the electroweak theory holds water.

Some scientists think the top quark may be special because its mass can verify or jeopardize the electroweak theory. If jeopardized, that opens the door to what physicists refer to as “new physics” — theories about particles and our universe that go beyond the Standard Model.

Other scientists theorize the top quark might also be key to the unification of the electromagnetic and weak interactions of protons, neutrons and quarks.

In addition, as the only quark that can be observed directly, the top quark tests the Standard Model’s strong force theory.

“So the top quark is really pushing both theories,” Kehoe said. “The top mass is particularly interesting because its measurement is getting to the point now where we are pushing even beyond the level that the theorists understand.”

He added, “Our experimental errors, or uncertainties, are so small, that it really forces theorists to try hard to understand the impact of the quark’s mass. We need to observe the Higgs interacting with the top directly and we need to measure both particles more precisely.”

The new measurement results were presented in August and September at the Third Annual Conference on Large Hadron Collider Physics, St. Petersburg, Russia, and at the 8th International Workshop on Top Quark Physics, Ischia, Italy.

“The public perception, with discovery of the Higgs, is ‘Ok, it’s done,’” Kehoe said. “But it’s not done. This is really just the beginning and the top quark is a key tool for figuring out the missing pieces of the puzzle.”

The results were made public by DZero, a collaborative experiment of more than 500 physicists from around the world. The measurement is described in “Precise measurement of the top quark mass in dilepton decays with optimized neutrino weighting” and is available online at arxiv.org/abs/1508.03322.

SMU measurement achieves surprising level of precision
To narrow the top quark measurement, SMU doctoral researcher Huanzhao Liu took a standard methodology for measuring the top quark and improved the accuracy of some parameters. He also improved calibration of an analysis of top quark data.

“Liu achieved a surprising level of precision,” Kehoe said. “And his new method for optimizing analysis is also applicable to analyses of other particle data besides the top quark, making the methodology useful within the field of particle physics as a whole.”

The SMU optimization could be used to more precisely understand the Higgs boson, which explains why matter has mass, said Liu.

The Higgs was observed for the first time in 2012, and physicists keenly want to understand its nature.

“This methodology has its advantages — including understanding Higgs interactions with other particles — and we hope that others use it,” said Liu. “With it we achieved 20-percent improvement in the measurement. Here’s how I think of it myself — everybody likes a $199 iPhone with contract. If someday Apple tells us they will reduce the price by 20 percent, how would we all feel to get the lower price?”

Another optimization employed by Liu improved the calibration precision by four times, Kehoe said.

Shower of Top quarks post Big Bang
Top quarks, which rarely occur now, were much more common right after the Big Bang 13.8 billion years ago. However, top is the only quark, of six different kinds, that can be observed directly. For that reason, experimental physicists focus on the characteristics of top quarks to better understand the quarks in everyday matter.

To study the top, physicists generate them in particle accelerators, such as the Tevatron, a powerful U.S. Department of Energy particle accelerator operated by Fermi National Laboratory in Illinois, or the Large Hadron Collider in Switzerland, a project of the European Organization for Nuclear Research, CERN.

SMU’s measurement draws on top quark data gathered by DZero that was produced from proton-antiproton collisions at the Tevatron, which Fermilab shut down in 2011.

The new measurement is the most precise of its kind from the Tevatron, and is competitive with comparable measurements from the Large Hadron Collider.

Critical question: Universe isn’t necessarily stable at all energies
“The ability to measure the top quark mass precisely is fortuitous because it, together with the Higgs boson mass, tells us whether the universe is stable or not,” Kehoe said. “That has emerged as one of today’s most important questions.”

A stable universe is one in a low energy state where particles and forces interact and behave according to theoretical predictions forever. That’s in contrast to metastable, or unstable, meaning a higher energy state in which things eventually change, or change suddenly and unpredictably, and that could result in the universe collapsing. The Higgs and top quark are the two most important parameters for determining an answer to that question, Kehoe said.

Recent measurements of the Higgs and top quark indicate they describe a universe that is not necessarily stable at all energies.

“We want a theory — Standard Model or otherwise — that can predict physical processes at all energies,” Kehoe said. “But the measurements now are such that it looks like we may be over the border of a stable universe. We’re metastable, meaning there’s a gray area, that it’s stable in some energies, but not in others.”

Are we facing imminent doom? Will the universe collapse?
That disparity between theory and observation indicates the Standard Model theory has been outpaced by new measurements of the Higgs and top quark.

“It’s going to take some work for theorists to explain this,” Kehoe said, adding it’s a challenge physicists relish, as evidenced by their preoccupation with “new physics” and the possibilities the Higgs and Top quark create.

“I attended two conferences recently,” Kehoe said, “and there’s argument about exactly what it means, so that could be interesting.”

So are we in trouble?

“Not immediately,” Kehoe said. “The energies at which metastability would kick in are so high that particle interactions in our universe almost never reach that level. In any case, a metastable universe would likely not change for many billions of years.”

Top quark — a window into other quarks
As the only quark that can be observed, the top quark pops in and out of existence fleetingly in protons, making it possible for physicists to test and define its properties directly.

“To me it’s like fireworks,” Liu said. “They shoot into the sky and explode into smaller pieces, and those smaller pieces continue exploding. That sort of describes how the top quark decays into other particles.”

By measuring the particles to which the top quark decays, scientists capture a measure of the top quark, Liu explained

But study of the top is still an exotic field, Kehoe said. “For years top quarks were treated as a construct and not a real thing. Now they are real and still fairly new — and it’s really important we understand their properties fully.” — Margaret Allen

Tags Dedman College, Huanzhao Liu, Robert Kehoe, SMU Department of Physics

Earth & Climate Energy & Matter Researcher news

Physicists tune Large Hadron Collider to find “sweet spot” in high-energy proton smasher

Post author By Margaret Allen
Post date April 14, 2015

New launch of the world’s most powerful particle accelerator is the most stringent test yet of our accepted theories of how subatomic particles work and interact.

Start up of the world’s largest science experiment is underway — with protons traveling in opposite directions at almost the speed of light in the deep underground tunnel called the Large Hadron Collider near Geneva.

As protons collide, physicists will peer into the resulting particle showers for new discoveries about the universe, said Ryszard Stroynowski, a collaborator on one of the collider’s key experiments and a professor in the Department of Physics at Southern Methodist University, Dallas.

“The hoopla and enthusiastic articles generated by discovery of the Higgs boson two years ago left an impression among many people that we have succeeded, we are done, we understand everything,” said Stroynowski, who is the senior member of SMU’s Large Hadron Collider team. “The reality is far from this. The only thing that we have found is that Higgs exist and therefore the Higgs mechanism of generating the mass of fundamental particles is possible.”

There is much more to be learned during Run 2 of the world’s most powerful particle accelerator.

The Large Hadron Collider, the most powerful proton smasher in the world, includes the ATLAS detector, one of the LHC's four particle detectors. (CERN) — The Large Hadron Collider, the most powerful proton smasher in the world, includes the ATLAS detector, one of the LHC’s four particle detectors. (CERN)

“In a way we kicked a can down the road because we still do not have sufficient precision to know where to look for the really, really new physics that is suggested by astronomical observations,” he said. “The observed facts that are not explained by current theory are many.”

The LHC’s control room in Geneva on April 5 restarted the Large Hadron Collider. A project of CERN, the European Organization for Nuclear Research, the 17-mile LHC tunnel — big enough to ride a bicycle through — straddles the border between France and Switzerland.

Two years ago it made headlines worldwide when its global collaboration of thousands of scientists discovered the Higgs Boson fundamental particle.

The Large Hadron Collider’s first run began in 2009. In 2012 it was paused for an extensive upgrade.

The new upgraded and supercharged LHC restarts at almost twice the energy and higher intensity than it was operating at previously, so it will deliver much more data.

The Liquid Argon Calorimeter sits at the heart of the ATLAS detector — Data flowing from the ATLAS detector’s Liquid Argon Calorimeter — which measures the energies carried by particle interactions — is delivered via a data link computer chip developed by physicists at Southern Methodist University. (CERN)

“I think that in the LHC Run 2 we will sieve through more data than in all particle physics experiments in the world together for the past 50 years,” Stroynowski said. “Nature would be really strange if we do not find something new.”

SMU is active on the LHC’s ATLAS detector experiment
Within the big LHC tunnel, gigantic particle detectors at four interaction points along the ring record the proton collisions that are generated when the beams collide.

In routine operation, protons make 11,245 laps of the LHC per second — producing up to 1 billion collisions per second. With that many collisions, each detector captures collision events 40 million times each second.

That’s a lot of collision data, says SMU physicist Robert Kehoe, a member of the ATLAS particle detector experiment with Stroynowski and other SMU physicists.

Evaluating that much data isn’t humanly possible, so a computerized ATLAS hardware “trigger system” grabs the data, makes a fast evaluation, decides if it might hold something of interest to physicists, than quickly discards or saves it.

The Liquid Argon Calorimeter sits at the heart of ATLAS, measuring the energies carried by particle interactions. (CERN)

“That gets rid of 99.999 percent of the data,” Kehoe said. “This trigger hardware system makes measurements — but they are very crude, fast and primitive.”

To further pare down the data, a custom-designed software program culls even more data from each nano-second grab, reducing 40 million events down to 200.

Two groups from SMU, one led by Kehoe, helped develop software to monitor the performance of the trigger systems’ thousands of computer processors.

“The software program has to be accurate in deciding which 200 to keep. We must be very careful that it’s the right 200 — the 200 that might tell us more about the Higgs boson, for example. If it’s not the right 200, then we can’t achieve our scientific goals.”

The ATLAS computers are part of CERN’s computing center, which stores more than 30 petabytes of data from the LHC experiments every year, the equivalent of 1.2 million Blu-ray discs.

Flood of data from ATLAS transmitted via tiny electronics designed at SMU to withstand harsh conditions
An SMU physics team also collaborates on the design, construction and delivery of the ATLAS “readout” system — an electronic system within the ATLAS trigger system that sends collision data from ATLAS to its data processing farm.

Data from the ATLAS particle detector’s Liquid Argon Calorimeter is transmitted via 1,524 small fiber-optic transmitters. A powerful and reliable workhorse, the link is one of thousands of critical components on the LHC that contributed to discovery and precision measurement of the Higgs boson.

The custom-made high-speed data transmitters were designed to withstand extremely harsh conditions — low temperature and high radiation.

“It’s not always a smooth ride operating electronics in such a harsh environment,” said Jingbo Ye, the physics professor who leads the SMU data-link team. “Failure of any transmitter results in the loss of a chunk of valuable data. We’re working to improve the design for future detectors because by 2017 and 2018, the existing optical data-link design won’t be able to carry all the data.”

Each electrical-to-optical and optical-to-electrical signal converter transmits 1.6 gigabytes of data per second. Lighter and smaller than their widely used commercial counterpart, the tiny, wickedly fast transmitters have been transmitting from the Liquid Argon Calorimeter for about 10 years.

Upgraded optical data link is now in the works to accommodate beefed-up data flow
A more powerful data link — much smaller and faster than the current one — is in research and development now. Slated for installation in 2017, it has the capacity to deliver 5.2 gigabytes of data per second.

The new link’s design has been even more challenging than the first, Ye said. It has a smaller footprint than the first, but handles more data, while at the same time maintaining the existing power supply and heat exchanger now in the ATLAS detector.

The link will have the highest data density in the world of any data link based on the transmitter optical subassembly TOSA, a standard industrial package, Ye said.

Fine-tuning the new, upgraded machine will take several weeks
The world’s most powerful machine for smashing protons together will require some “tuning” before physicists from around the world are ready to take data, said Stephen Sekula, a researcher on ATLAS and assistant professor of physics at SMU.

The trick is to get reliable, stable beams that can remain in collision state for 8 to 12 to 24 hours at a time, so that the particle physicists working on the experiments, who prize stability, will be satisfied with the quality of the beam conditions being delivered to them, Sekula said.

“The LHC isn’t a toaster,” he said. “We’re not stamping thousands of them out of a factory every day, there’s only one of them on the planet and when you upgrade it it’s a new piece of equipment with new idiosyncrasies, so there’s no guarantee it will behave as it did before.”

Machine physicists at CERN must learn the nuances of the upgraded machine, he said. The beam must be stable, so physicists on shifts in the control room can take high-quality data under stable operating conditions.

The process will take weeks, Sekula said.

10 times as many Higgs particles means a flood of data to sift for gems
LHC Run 2 will collide particles at a staggering 13 teraelectronvolts (TeV), which is 60 percent higher than any accelerator has achieved before.

“On paper, Run 2 will give us four times more data than we took on Run 1,” Sekula said. “But each of those multiples of data are actually worth more. Because not only are we going to take more collisions, we’re going to do it at a higher energy. When you do more collisions and you do them at a higher energy, the rate at which you make Higgs Bosons goes way up. We’re going to get 10 times more Higgs than we did in run 1 — at least.”

SMU’s ManeFrame supercomputer plays a key role in helping physicists from the Large Hadron Collider experiments. One of the fastest academic supercomputers in the nation, it allows physicists at SMU and around the world to sift through the flood of data, quickly analyze massive amounts of information, and deliver results to the collaborating scientists.

During Run 1, the LHC delivered about 8,500 Higgs particles a week to the scientists, but also delivered a huge number of other kinds of particles that have to be sifted away to find the Higgs particles. Run 2 will make 10 times that, Sekula said. “So they’ll rain from the sky. And with more Higgs, we’ll have an easier time sifting the gems out of the gravel.”

Run 2 will operate at the energy originally intended for Run 1, which was initially stalled by a faulty electrical connection on some superconducting magnets in a sector of the tunnel. Machine physicists were able to get the machine running — just never at full power. And still the Higgs was discovered, notes SMU physics professor Fredrick Olness.

“The 2008 magnet accident at the LHC underscores just how complex a machine this is,” Olness said. “We are pushing the technology to the cutting-edge.”

Huge possibilities for new discoveries, but some will be more important than others
There are a handful of major new discoveries that could emerge from Run 2 data, Stroynowski said.

New physics laws related to Higgs — Physicists know only global Higgs properties, many with very poor understanding. They will be measuring Higgs properties with much greater precision, and any deviation from the present picture will indicate new physics laws. “Improved precision is the only guaranteed outcome of the coming run,” Stroynowski said. “But of course we hope that not everything will be as expected. Any deviation may be due to supersymmetry or something completely new.”
Why basic particles have such a huge range of masses — Clarity achieved by precision measurements of Higgs properties may help to shed light on the exact reason for the pattern of masses found in the known fundamental particles. If new particles are discovered in the LHC during Run 2, the mathematical theories that could explain them might also shed light on the puzzle of why masses have such diversity in the building blocks of nature
Dark matter — Astronomical observations require a new form of matter that acts only via gravity, otherwise all galaxies would have fallen apart a long time ago. One candidate theory is supersymmetry, which predicts a host of new particles. Some of those particles, if they exist, would fit the characteristics of dark matter. LHC scientists will be looking for them in the coming run both directly, and for indirect effects.
Quark gluon plasma — In collisions of lead nuclei with each other, LHC scientists have observed a new form of matter called quark gluon plasma. Thought to have been present in the cosmos near the very beginning of time, making and studying this state of matter could teach us more about the early, hot, dense universe.
Mini black-holes — Some scientists are looking for “mini black-holes” predicted by innovative physicist Stephen Hawking, but that is considered “a v-e-e-e-e-r-y long shot,” Stroynowski said.
Matter-antimatter — A cosmic imbalance in the amounts of matter and its opposite, antimatter, must be explained by particle physics. The LHC is home to several experiments and teams that aim to search for answers.

— SMU, Fermilab, CERN

Tags Andrew Turvey, Annie C. Xiang, Ashleigh Miller, Dedman College, Fredrick Olness, Jingbo Ye, Matthew Stein, Robert Kehoe, Ryszard Stroynowski, Sami Kama, SMU Department of Physics, Stephen J. Sekula

Earth & Climate Energy & Matter Learning & Education Researcher news SMU In The News Student researchers

KERA: Telescope-Wielding Twosome: High School Students Discover New Stars

Post author By Margaret Allen
Post date September 5, 2014

Their five stars will be known by 16-digit serial numbers. Dominik would have rather immortalized his four dogs.

Lake Highlands High School students Dominik Fritz (left) and Jason Barton collected data until they had what they needed to define their star-to-be as a variable — a star that changes brightness. (Credit: KERA) — Lake Highlands High School students Dominik Fritz (right) and Jason Barton collected data until they had what they needed to define their star-to-be as a variable — a star that changes brightness. (Credit: KERA)

Reporter Courtney Collins with the news team at public radio station KERA covered the discovery of five stars made by two Dallas high school students as members of an SMU summer physics research program. Called Quarknet, the program enabled the students to analyze data gleaned from a high-powered telescope in the New Mexico desert.

All five stars are eclipsing contact binary stars, pairs of stars that orbit around each other so closely that their outer atmospheres touch. As the stars eclipse, they dim and then brighten as one emerges from behind the other. These stars are categorized as variable stars, stars that change brightness, which make up half the stars in the universe.

Lake Highlands High School seniors Dominik Fritz and Jason Barton are the first high school researchers at SMU to discover new stars.

Fritz and Barton are among nine high school students and two high school physics teachers who conducted physics research at SMU through the QuarkNet program.

Collins’ segment published and aired Sept. 4, “Telescope-Wielding Twosome: High School Students Discover New Stars.”

Listen to the segment and read the full story.

EXCERPT:

By Courtney Collins
KERA News
To most teenagers, star-gazing is the stuff of first dates.

For two seniors at Lake Highlands High School in Dallas, star-gazing over the summer led to five unusual discoveries.

In some respects, Dominik Fritz and Jason Barton are typical high-schoolers. Jason’s haircut would make a pop star envious and Dominik’s snazzy specs are effortlessly cool.

When these two kids start to talk science, you realize quickly, they’re two in a million.

“I’m personally fascinated by nuclear reactions and that’s basically what happens in stars, it’s full of nuclear reactions, nuclear fusion, a little bit of fission,” Dominik says.

That set of interests made Dominik a perfect candidate for a summer physics program at SMU. Jason and two other Richardson school district students joined him.

While analyzing data from a high-powered telescope, Jason noticed a few stars that weren’t already in the database.

“I started looking over several nights and seeing if they were actual variable stars and if they did change in brightness over time, and then I combined them all and then I eventually submitted it,” Jason says.

In fact, both teens made submission to an international star index that were accepted. Between them, they’d discovered five eclipsing binary contact stars. Dominik translates:

“Two very, very large star systems that are so close that they actually share their atmospheres.”

Lake Highlands physics teacher Ken Taylor says not many kids make it to upper level physics. That’s why he was so keen to get these students out of the textbook and into real research.

“It was beautiful for me to see my students who were going and forging ahead and taking things that they had learned and going into new territory and seeing the looks on their faces when they began to go somewhere where, in a sense, no one had gone before.”

Listen to the segment and read the full story.

Tags Dedman College, Dominik Fritz, Farley Ferrante, Jason Barton, Ken Taylor, Robert Kehoe, SMU Department of Physics

Earth & Climate Energy & Matter Researcher news SMU In The News Student researchers

DMN: Two high school students discover variable stars during SMU summer program

Post author By Margaret Allen
Post date August 25, 2014

Two high school students collected data until they had what they needed to define their star-to-be as a variable — a star that changes brightness.

Reporter Alexis Espinosa with the Dallas Morning News covered the discovery of five stars made by two Dallas high school students as members of an SMU summer physics research program. Called Quarknet, the program enabled the students to analyze data gleaned from a high-powered telescope in the New Mexico desert.

Lake Highlands High School seniors Dominik Fritz and Jason Barton are the first high school researchers at SMU to discover new stars.

Fritz and Barton are among nine high school students and two high school physics teachers who conducted physics research at SMU through the QuarkNet program.

Read the full story.

EXCERPT:

By Alexis Espinosa
Dallas Morning News
Dominik Fritz sat in a Southern Methodist University science lab sifting through data. He hoped to discover a star by searching through months of information collected from a telescope in the New Mexico desert 14 years ago.
And then he found it.

He found a star whose variation had not yet been defined. And he would be the one to define it.

He collected data until he had everything he needed to define it as a variable — a star that changes brightness. A day after he submitted the star to the American Association of Variable Star Observers, the organization requested a few minor corrections.

And then, his star was accepted.

“I was so, so happy. My name is out there. I felt like I really accomplished something,” Fritz said. “I can literally tell people … ‘I found a star.’”

Fritz and a classmate, Jason Barton, both discovered stars this summer as part of the SMU’s QuarkNet program.

QuarkNet is a physics teacher development program funded by the National Science Foundation and the U.S. Department of Energy in universities and laboratories across the country. SMU’s QuarkNet program, which began in 2000, also provides research opportunities to high school students like Fritz and Barton, who are seniors at Lake Highlands High School in Richardson ISD.

Read the full story.

Tags Dedman College, Dominik Fritz, Farley Ferrante, Jason Barton, Ken Taylor, Robert Kehoe, SMU Department of Physics

Earth & Climate Energy & Matter Learning & Education Student researchers

Eclipsing binary stars discovered by high school students at SMU summer research program

Post author By Margaret Allen
Post date August 20, 2014

Treasures of the night sky: Pairs of stars orbit around each other so closely their outer atmospheres touch, so they dim and brighten.

Artist's impression of an eclipsing binary star system. As the two stars orbit each other they pass in front of one another and their combined brightness, seen from a distance, decreases. — Artist’s impression of an eclipsing binary star system. The stars pass in front of one another and their combined brightness decreases. (Credit: European Southern Observatory)

Two Dallas high school students discovered five stars as members of an SMU summer physics research program that enabled them to analyze data gleaned from a high-powered telescope in the New Mexico desert.

Lake Highlands High School seniors Dominik Fritz and Jason Barton are the first high school researchers at SMU to discover new stars.

Their discoveries have been accepted into the American Association of Variable Star Observers International Variable Star Index (VSX).

New discoveries in Pegasus, Ursa Major are registered with Variable Star Index

The stars are located in the northern sky constellations of Pegasus and Ursa Major, but can’t be seen by the naked eye.

Lake Highlands High School student Dominik Fritz and teacher Ken Taylor at SMU. Fritz participated in Quarknet, a Dedman Physics program for area high school students. (Photo Credit here) — Lake Highlands High School student Dominik Fritz and teacher Ken Taylor at SMU. Fritz participated in Quarknet, an SMU Physics Department program for area high school students. (Photo Credit here)

Working in a campus science building basement laboratory, the students used analysis software, perseverance and patience to parse the data collected (but never analyzed for the purpose of studying binary stars) in 2000 by Robert Kehoe, SMU associate professor of physics.

Kehoe collected the data through ROTSE-I, a prototype robotic telescope at Los Alamos, New Mexico.

“Scientists are driven by the sense of discovery,” says Kehoe, who took the data originally to study gamma ray bursts. “These students can lay claim to information that didn’t exist before their research.”

SMU only university in North Texas offering the nation’s QuarkNet program
Fritz and Barton are among nine high school students and two high school physics teachers conducting physics research at SMU through the QuarkNet program.

QuarkNet is a physics teacher development program with 50 centers at U.S. universities and national laboratories. Funded by the National Science Foundation and the U.S. Department of Energy, the program gives teachers and students opportunities to learn about the most recent discoveries in physics.

Other sponsors include two of the world’s leading high-energy physics research centers — CERN in Switzerland and Fermilab in Illinois. SMU is one of four Texas universities to offer the QuarkNet program and the only QuarkNet university in North Texas.

“High school physics curriculum includes very little modern physics,” says Simon Dalley, a member of the SMU physics faculty and coordinator of its QuarkNet program. “This hurts recruitment to the field and prevents the general population from understanding physics’ contribution to the modern world.”

Ken Taylor, Lake Highlands High School physics teacher, is determined to introduce new physics research to his students. He has participated in QuarkNet at SMU since 2000, seizing opportunities to join physics researchers at high-energy particle colliders at CERN and Fermilab. This is the first summer he has selected students to join him in physics research at SMU.

“I like to support students beyond the classroom walls,” he says. “These students have gone through the whole process of scientific discovery and can use these projects as jumping off points for the next phases of their lives.”

With acceptance into the VSX catalog of variable stars, the students’ names are forever linked with their stars on the official registry.

But instead of creating new star names, star discoverers follow a protocol that includes the name of the telescope and the stellar coordinates.

Dominik Fritz discovered ROTSE1 J115128.40+493130.5, ROTSE1 J120809.03+503321.7 and ROTSE1 J232109.31+170125.6.

Jason Barton can include his stars, ROTSE1 J223452.37+175210.5 and ROTSE1 J223707.20+212657.9, on his resume.

Both students plan to pursue science careers, Fritz in nuclear engineering and Barton in medicine.

Other student QuarkNet researchers include KeShawn Ivory from Garland High School and Madison Monzingo and Lane Toungate from Lake Highlands High School. In addition, Hockaday School teacher Leon de Oliveira and his four students – Eliza Cope, Allison Aldrich, Sarah Zhou and Mary Zhong — also conducted QuarkNet research this summer.

“These students have made a real contribution to science,” says Farley Ferrante, the former high school physics teacher and current SMU astrophysics graduate student who supervised the students’ research. “A better understanding of variable stars helps us to understand the age and formation of the universe; the sun, which is a variable star; and even the possibility of extra-terrestrial life.”

Tags Dedman College, Dominik Fritz, Farley Ferrante, Ken Taylor, Robert Kehoe, SMU Department of Physics

Earth & Climate Energy & Matter Researcher news SMU In The News Student researchers

Houston Chronicle: Texas scientists spot 12-billion-year old star explosion

Post author By Margaret Allen
Post date June 8, 2014

“You’re looking at things a long time ago in the universe, you can get a sense for the movie of the universe,” said Kehoe. “It’s the evolution of the universe.”

The Texas newspaper the Houston Chronicle covered the astronomy research of physicist Robert Kehoe, SMU professor, and two graduate students in the SMU Department of Physics, Farley Ferrante and Govinda Dhungana.

The astronomy team in May reported observation of intense light from the enormous explosion of a star more than 12 billion years ago — shortly after the Big Bang — that recently reached Earth and was visible in the sky.

Known as a gamma-ray burst, light from the rare, high-energy explosion traveled for 12.1 billion years before it was detected and observed by a telescope, ROTSE-IIIb, owned by SMU.

Recorded as GRB 140419A by NASA’s Gamma-ray Coordinates Network, the burst was spotted at 11 p.m. April 19 by SMU’s robotic telescope at the McDonald Observatory in the Davis Mountains of West Texas.

Houston Chronicle reporter Heather Alexander reported the news in his article “Texas scientists spot 12-billion-year old star explosion.”

Read the full story.

EXCERPT:

By Heather Alexander
Houston Chronicle

Texas scientists have spotted a massive explosion in space that dates back 12 billion years, almost to the time of the Big Bang, according to Southern Methodist University in Dallas.

NASA satellites recorded the burst and signalled back to the McDonald Observatory in West Texas. Telescope pictures showed a gamma ray burst, believed to be the collapse of a star.

“Gamma-ray bursts are the most powerful explosions in the universe since the Big Bang,” said graduate student Farley Ferrante, who was monitoring the telescope. “These bursts release more energy in 10 seconds than our Earth’s sun during its entire expected lifespan of 10 billion years.”

The scientists said explosions like this are key to understanding the development of the universe.

“Twelve billion years ago, it was a very different universe,” said Robert Kehoe, physics professor and leader of the SMU astronomy team. “It was just hydrogen and helium. There were no rocks, there was no matter; our solar system had not formed.”

Kehoe says explosions like the one shown in the photo are stars exploding, scattering new elements like carbon, oxygen, silicon and iron into the surrounding area.

Read the full story.

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For more information, www.smuresearch.com.

SMU is a nationally ranked private university in Dallas founded 100 years ago. Today, SMU enrolls nearly 11,000 students who benefit from the academic opportunities and international reach of seven degree-granting schools. For more information see www.smu.edu.

SMU has an uplink facility located on campus for live TV, radio, or online interviews. To speak with an SMU expert or book an SMU guest in the studio, call SMU News & Communications at 214-768-7650.

Tags Dedman College, Farley Ferrante, Govinda Dhungana, Robert Kehoe, SMU Department of Physics

Earth & Climate Energy & Matter Researcher news SMU In The News Student researchers

Digital Journal: Scientists spot 12-billion-year-old star burst

Post author By Margaret Allen
Post date June 8, 2014

A star exploded billions of years back, but the light of this explosion has just reached the earth, allowing scientists to peep into the past of the universe

The news web site digitaljournal.com covered the astronomy research of physicist Robert Kehoe, SMU professor, and two graduate students in the SMU Department of Physics, Farley Ferrante and Govinda Dhungana.

Known as a gamma-ray burst, light from the rare, high-energy explosion traveled for 12.1 billion years before it was detected and observed by a telescope, ROTSE-IIIb, owned by SMU.

Digitaljournal.com reporter Sonia D’Costa reported the news in her article “Scientists spot 12-billion-year-old star burst.”

Read the full story.

EXCERPT:

By Sonia D’Costa
digitaljournal.com

A star exploded billions of years back, but the light of this explosion has just reached the earth, allowing scientists to peep into the past of the universe and figure out what it might have been like during the earliest stages of its development.

The light was observed through a telescope at the McDonald Observatory at Fort Davis in Texas. Called a gamma-ray burst, this stellar explosion is believed to have taken place just after the Big Bang, over 12 billion years in the past.

Farley Ferrante, a physics student at the Southern Methodist University (SMU), which owns the telescope, said: “Gamma-ray bursts are the most powerful explosions in the universe since the Big Bang. These bursts release more energy in 10 seconds than our Earth’s sun during its entire expected lifespan of 10 billion years.”

Read the full story.

Follow SMUResearch.com on Twitter.

For more information, www.smuresearch.com.

Tags Dedman College, Farley Ferrante, Govinda Dhungana, Robert Kehoe, SMU Department of Physics

Earth & Climate Energy & Matter Researcher news SMU In The News

Global Post: Light from this 12-billion-year-old explosion just reached Earth

Post author By Margaret Allen
Post date June 7, 2014

To put the age of the latest discovery into context, scientists believe the Big Bang occurred 13.81 billion years ago.

The news service Global Post covered the astronomy research of physicist Robert Kehoe, SMU professor, and two graduate students in the SMU Department of Physics, Farley Ferrante and Govinda Dhungana.

Known as a gamma-ray burst, light from the rare, high-energy explosion traveled for 12.1 billion years before it was detected and observed by a telescope, ROTSE-IIIb, owned by SMU.

Global Post reporter Sarah Wolfe reported the news in his article “Light from this 12-billion-year-old explosion just reached Earth.”

Read the full story.

EXCERPT:

By Sarah Wolfe
Global Post

It took 12 billion years, but light from a massive explosion that occurred shortly after the Big Bang has just reached Earth.

The rare gamma-ray burst could help scientists understand more about the early universe.

Recorded as GRB 140423A, the explosion was first observed in April by the telescope Rotse-IIIB at an observatory in western Texas owned by Southern Methodist University.

The area of the explosion’s peak afterglow, circled in blue and yellow, can be seen in the image above. A bright star sits to its left.

Gamma-ray bursts are believed to be the catastrophic collapse of a star at the end of its life.

“As NASA points out, gamma-ray bursts are the most powerful explosions in the universe since the Big Bang,” Farley Ferrante, a graduate student at Southern Methodist University who monitored the explosions with astronomers in Hawaii and Turkey, said in a release from the university.

“These bursts release more energy in 10 seconds than our Earth’s sun during its entire expected lifespan of 10 billion years.”

Scientists weren’t even able to detect visual light from gamma-ray bursts until technology improved in the late 1990s. Gamma rays have the shortest wavelengths and can only be seen using special detectors.

Read the full story.

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For more information, www.smuresearch.com.

Tags Dedman College, Farley Ferrante, Govinda Dhungana, Robert Kehoe, SMU Department of Physics

Earth & Climate Energy & Matter Researcher news SMU In The News

CBS News: See an exploding star from 12 billion years ago

Post author By Margaret Allen
Post date June 7, 2014

Armed with images of the burst, astronomers can now analyze the data in order to understand more about the structure of the universe at its infancy

CBS News covered the astronomy research of physicist Robert Kehoe, SMU professor, and two graduate students in the SMU Department of Physics, Farley Ferrante and Govinda Dhungana.

Known as a gamma-ray burst, light from the rare, high-energy explosion traveled for 12.1 billion years before it was detected and observed by a telescope, ROTSE-IIIb, owned by SMU.

CBS News reporter Hani Shawwa reported the news in his article “See an exploding star from 12 billion years ago.”

Read the full story.

EXCERPT:

By Hani Shawwa
CBS News

It took billions of years for the light of this cosmic explosion to reach Earth, and now it’s offering scientists a rare glimpse of the universe at one of its earliest stages.

A McDonald Observatory telescope in Fort Davis, Texas captured the image of a gamma-ray burst — the enormous explosion of a star, which took place more than 12 billion years ago, shortly after the Big Bang.

“Gamma-ray bursts are the most powerful explosions in the universe since the Big Bang. These bursts release more energy in 10 seconds than our Earth’s sun during its entire expected lifespan of 10 billion years,” said Farley Ferrante, a graduate student at Southern Methodist University’s Department of Physics, who monitored the explosion along with two astronomers in Turkey and Hawaii.

The phenomenon is not well understood by astronomers, but it is believed to be the result of a catastrophic collapse of a star at the end of its life.

“Gamma-ray bursts may be particularly massive cousins to supernovae… By studying them, we learn about supernovae,” said Robert Kehoe, physics professor and leader of the SMU astronomy team.

The photo was snapped in mid-April and released this week.

Scientists weren’t able to detect optical light from gamma-ray bursts until the late 1990s, when telescope technology improved.

Among all lights in the electromagnetic spectrum, gamma rays have the shortest wavelengths and are visible only using special detectors.

Read the full story.

Follow SMUResearch.com on Twitter.

For more information, www.smuresearch.com.

Tags Dedman College, Farley Ferrante, Govinda Dhungana, Robert Kehoe, SMU Department of Physics

Earth & Climate Energy & Matter Researcher news SMU In The News

Daily Mail: Huge 12 billion-year-old explosion in space has been spotted from Earth – and it could reveal secrets of the early universe

Post author By Margaret Allen
Post date June 6, 2014

Armed with images of the burst, astronomers can now analyze the data in order to understand more about the structure of the universe at its infancy

The U.K.’s widely read newspaper the Daily Mail covered the astronomy research of physicist Robert Kehoe, SMU professor, and two graduate students in the SMU Department of Physics, Farley Ferrante and Govinda Dhungana.

Known as a gamma-ray burst, light from the rare, high-energy explosion traveled for 12.1 billion years before it was detected and observed by a telescope, ROTSE-IIIb, owned by SMU.
Gamma-ray bursts are believed to be the catastrophic collapse of a star at the end of its life. SMU physicists report that their telescope was the first on the ground to observe the burst and to capture an image.

Daily Mail reporter Jonathan O’Callaghan reported the news in his article “Huge 12 billion-year-old explosion in space has been spotted from Earth – and it could reveal secrets of the early universe.”

Read the full story.

EXCERPT:

By Jonathan O’Callaghan
Daily Mail

One of the biggest and hottest explosions in the universe – a rare event known as a gamma-ray burst (GRB) – has been spotted on camera.

And this particular event, caused by the enormous explosions of a star, occurred shortly after the Big Bang about 12.1 billion years ago.

The intense light recently reached Earth and it could give astronomers useful information about the conditions in the young universe.

Gamma-ray bursts are believed to be the catastrophic collapse of a star at the end of its life.

The observation was made by the telescope Rotse-IIIB at the McDonald Observatory in the Davis Mountains of West Texas, owned by the Southern Methodist University (SMU) in Dallas.

SMU physicists report that their telescope was the first on the ground to observe the burst, and to capture an image.

This particular explosion, first spotted back in April, was recorded as GRB 140419A by Nasa’s Gamma-ray Coordinates Network (GCN).

Gamma-ray bursts are not well understood by astronomers, but they are considered important, according to Farley Ferrante, a graduate student in SMU’s Department of Physics, who monitored the observations along with two astronomers in Turkey and Hawaii.

‘As Nasa points out, gamma-ray bursts are the most powerful explosions in the universe since the Big Bang,’ he said.

‘These bursts release more energy in 10 seconds than our Earth’s sun during its entire expected lifespan of 10 billion years.’

Some of these GRBs appear to be related to supernovae and correspond to the end-of-life of a massive star, said Dr Robert Kehoe, physics professor and leader of the SMU astronomy team.

‘Gamma-ray bursts may be particularly massive cousins to supernovae, or may correspond to cases in which the explosion ejecta are more beamed in our direction. By studying them, we learn about supernovae,’ Kehoe said.

Read the full story.

Tags Dedman College, Farley Ferrante, Govinda Dhungana, Robert Kehoe, SMU Department of Physics

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Observed by Texas telescope: Light from huge explosion 12 billion years ago reaches Earth

Post author By Margaret Allen
Post date June 3, 2014

Known as a gamma-ray burst, the intense light captured in the night sky resulted from one of the biggest and hottest explosions in the universe, occurring shortly after the Big Bang.

Intense light from the enormous explosion of a star more than 12 billion years ago — shortly after the Big Bang — recently reached Earth and was visible in the sky.

Known as a gamma-ray burst, light from the rare, high-energy explosion traveled for 12.1 billion years before it was detected and observed by a telescope, ROTSE-IIIb, owned by Southern Methodist University, Dallas.

Gamma-ray bursts are believed to be the catastrophic collapse of a star at the end of its life. SMU physicists report that their telescope was the first on the ground to observe the burst and to capture an image, said Farley Ferrante, a graduate student in SMU’s Department of Physics, who monitored the observations along with two astronomers in Turkey and Hawaii.

Gamma-ray burst 1404191 was spotted at 11 p.m. on April 19 by SMU's robotic ROTSE-IIIb telescope at McDonald Observatory, Fort Davis, Texas. — Gamma-ray burst 1404191 was spotted at 11 p.m. April 19 by SMU’s robotic ROTSE-IIIb telescope at McDonald Observatory, Fort Davis, Texas.

Gamma-ray bursts are not well understood by astronomers, but they are considered important, Ferrante said.

“As NASA points out, gamma-ray bursts are the most powerful explosions in the universe since the Big Bang,” he said. “These bursts release more energy in 10 seconds than our Earth’s sun during its entire expected lifespan of 10 billion years.”

Some of these gamma-ray bursts appear to be related to supernovae, and correspond to the end-of-life of a massive star, said Robert Kehoe, physics professor and leader of the SMU astronomy team.

“Gamma-ray bursts may be particularly massive cousins to supernovae, or may correspond to cases in which the explosion ejecta are more beamed in our direction. By studying them, we learn about supernovae,” Kehoe said.

Scientists weren’t able to detect optical light from gamma-ray bursts until the late 1990s, when telescope technology improved. Among all lights in the electromagnetic spectrum, gamma rays have the shortest wavelengths and are visible only using special detectors.

Gamma-ray bursts result from hot stars that measure as enormous as 50 solar masses. The explosion occurs when the stars run out of fuel and collapse in on themselves, forming black holes.

The ROTSE-IIIb robotic telescope at McDonald Observatory, Fort Davis, Texas. (Photo: McDonald Observatory)

Outer layers detonate, shooting out material along the rotation axis in powerful, high-energy jets that include gamma radiation.

As the gamma radiation declines, the explosion produces an afterglow of visible optical light. The light, in turn, fades very quickly, said Kehoe. Physicists calculate the distance of the explosion based on the shifting wavelength of the light, or redshift.

“The optical light is visible for anywhere from a few seconds to a few hours,” Kehoe said. “Sometimes optical telescopes can capture the spectra. This allows us to calculate the redshift of the light, which tells us how fast the light is moving away from us. This is an indirect indication of the distance from us.”

Observational data from gamma-ray bursts allows scientists to understand structure of the early universe
To put into context the age of the new gamma-ray burst discoveries, Kehoe and Ferrante point out that the Big Bang occurred 13.81 billion years ago. GRB 140419A is at a red shift of 3.96, Ferrante said.

“That means that GRB 140419A exploded about 12.1 billion years ago,” he said, “which is only about one-and-a-half billion years after the universe began. That is really old.”

Armed with images of the burst, astronomers can analyze the observational data to draw further conclusions about the structure of the early universe.

“At the time of this gamma-ray burst’s explosion, the universe looked vastly different than it does now,” Kehoe said. “It was an early stage of galaxy formation. There weren’t heavy elements to make Earth-like planets. So this is a glimpse at the early universe. Observing gamma-ray bursts is important for gaining information about the early universe.”

GRB 140419A’s brightness, measured by its ability to be seen by someone on Earth, was of the 12th magnitude, Kehoe said, indicating it was only 10 times dimmer than what is visible through binoculars, and only 200 times dimmer than the human eye can see, Kehoe said.

“The difference in brightness is about the same as between the brightest star you can see in the sky, and the dimmest you can see with the naked eye on a clear, dark night,” Kehoe said. “Considering this thing was at the edge of the visible universe, that’s an extreme explosion. That was something big. Really big.”

SMU telescope responded to NASA satellite’s detection and notification
SMU’s Robotic Optical Transient Search Experiment (ROTSE) IIIb is a robotic telescope. It is part of a network of ground telescopes responsive to a NASA satellite that is central to the space agency’s Swift Gamma-Ray Burst Mission. Images of the gamma-ray bursts are at http://bit.ly/1kKZeh5.

When the Swift satellite detects a gamma-ray burst, it instantly relays the location. Telescopes around the world, such as SMU’s ROTSE-IIIb, swing into action to observe the burst’s afterglow and capture images, said Govinda Dhungana, an SMU graduate student who participated in the gamma-ray burst research.

SMU’s ROTSE-IIIb observes optical emission from several gamma-ray bursts each year. It observed GRB 140419A just 55 seconds after the burst was detected by Swift.

Just days later, ROTSE-IIIb observed and reported a second rare and distant gamma-ray burst, GRB 140423A, at 3:30 a.m. April 23. The redshift of that burst corresponds to a look back in time of 11.8 billion years. ROTSE-IIIb observed it 51 seconds after the burst was detected by Swift.

“We have the brightest detection and the earliest response on both of those because our telescope is fully robotic and no human hands were involved,” Ferrante said.

Ferrante, the first to check observations on GRB 140423A, is first-author on that gamma-ray burst. Tolga Guver, associate professor in the Department of Astronomy and Space Sciences at Istanbul University, Turkey, is second author. On GRB 140419A, Guver is first author and Ferrante is second.

The research is funded by the Texas Space Grant Consortium, an affiliate of NASA. — Margaret Allen

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SMU physicists celebrate Nobel Prize for discovery of Higgs boson “god particle”

Post author By Margaret Allen
Post date October 8, 2013

SMU joins nearly 2,000 physicists from U.S. institutions — including 89 U.S. universities and seven U.S. DOE labs — that participate in discovery experiments

SMU’s experimental physics group played a pivotal role in discovering the Higgs boson — the particle that proves the theory for which two scientists have received the 2013 Nobel Prize in Physics.

The Royal Swedish Academy of Sciences today awarded the Nobel Prize to theorists Peter W. Higgs and François Englert to recognize their work developing the theory of what is now known as the Higgs field, which gives elementary particles mass. U.S. scientists played a significant role in advancing the theory and in discovering the particle that proves the existence of the Higgs field, the Higgs boson.

The Nobel citation recognizes Higgs and Englert “for the theoretical discovery of a mechanism that contributes to our understanding of the origin of mass of subatomic particles, and which recently was confirmed through the discovery of the predicted fundamental particle, by the ATLAS and CMS experiments at CERN’s Large Hadron Collider.”

In the 1960s, Higgs and Englert, along with other theorists, including Robert Brout, Tom Kibble and Americans Carl Hagen and Gerald Guralnik, published papers introducing key concepts in the theory of the Higgs field. In 2012, scientists on the international ATLAS and CMS experiments, performed at the Large Hadron Collider at CERN laboratory in Europe, confirmed this theory when they announced the discovery of the Higgs boson.

“A scientist may test out a thousand different ideas over the course of a career. If you’re fortunate, you get to experiment with one that works,” says SMU physicist Ryszard Stroynowski, a principal investigator in the search for the Higgs boson. As the leader of an SMU Department of Physics team working on the experiment, Stroynowski served as U.S. coordinator for the ATLAS Experiment’s Liquid Argon Calorimeter, which measures energy from the particles created by proton collisions.

The University’s experimental physics group has been involved since 1994 and is a major contributor to the research, the heart of which is the Large Hadron Collider particle accelerator on the border with Switzerland and France.

SMU joins nearly 2,000 physicists from U.S. institutions — including 89 U.S. universities and seven U.S. Department of Energy laboratories — that participate in the ATLAS and CMS experiments, making up about 23 percent of the ATLAS collaboration and 33 percent of CMS at the time of the Higgs discovery. Brookhaven National Laboratory serves as the U.S. hub for the ATLAS experiment, and Fermi National Accelerator Laboratory serves as the U.S. hub for the CMS experiment. U.S. scientists provided a significant portion of the intellectual leadership on Higgs analysis teams for both experiments.

Preliminary discovery results were announced July 4, 2012 at CERN, the European Organization for Nuclear Research, near Geneva, Switzerland, and at the International Conference of High Energy Physics in Melbourne, Australia.

“It is an honor that the Nobel Committee recognizes these theorists for their role in predicting what is one of the biggest discoveries in particle physics in the last few decades,” said Fermilab Director Nigel Lockyer. “I congratulate the whole particle physics community for this achievement.”

The majority of U.S. scientists participating in LHC experiments work primarily from their home institutions, remotely accessing and analyzing data through high-capacity networks and grid computing. The United States plays an important role in this distributed computing system, providing 23 percent of the computing power for ATLAS and 40 percent for CMS. The United States also supplied or played a leading role in several main components of the two detectors and the LHC accelerator, amounting to a value of $164 million for the ATLAS detector, $167 million for the CMS detector, and $200 million for the LHC. Support for the U.S. effort comes from the U.S. Department of Energy Office of Science and the National Science Foundation.

“It’s wonderful to see a 50-year-old theory confirmed after decades of hard work and remarkable ingenuity,” said Brookhaven National Laboratory Director Doon Gibbs. “The U.S. has played a key role, contributing scientific and technical expertise along with essential computing and data analysis capabilities — all of which were necessary to bring the Higgs out of hiding. It’s a privilege to share in the success of an experiment that has changed the face of science.”

The discovery of the Higgs boson at CERN was the culmination of decades of effort by physicists and engineers around the world, at the LHC but also at other accelerators such as the Tevatron accelerator, located at Fermilab, and the Large Electron Positron accelerator, which once inhabited the tunnel where the LHC resides. Work by scientists at the Tevatron and LEP developed search techniques and eliminated a significant fraction of the space in which the Higgs boson could hide.

Several contributors from SMU have made their mark on the project at various stages, including current Department of Physics faculty members Ryszard Stroynowski, Jingbo Ye, Robert Kehoe and Stephen Sekula. Faculty members Pavel Nadolsky and Fred Olness performed theoretical calculations used in various aspects of data analysis.

University postdoctoral fellows on the ATLAS Experiment have included Julia Hoffmann, David Joffe, Ana Firan, Haleh Hadavand, Peter Renkel, Aidan Randle-Conde and Daniel Goldin.

SMU has awarded eight Ph.D. and seven M.Sc. degrees to students who performed advanced work on ATLAS, including Ryan Rios, Rozmin Daya, Renat Ishmukhametov, Tingting Cao, Kamile Dindar, Pavel Zarzhitsky and Azzedin Kasmi.

Significant contributions to ATLAS have also been made by SMU faculty members in the Department of Physics’ Optoelectronics Lab, including Tiankuan Liu, Annie Xiang and Datao Gong.

“The discovery of the Higgs is a great achievement, confirming an idea that will require rewriting of the textbooks,” Stroynowski says. “But there is much more to be learned from the LHC and from ATLAS data in the next few years. We look forward to continuing this work.”

Higgs and Englert published their papers independently and did not meet in person until the July 4, 2012, announcement of the discovery of the Higgs boson at CERN. Higgs, 84, is a professor emeritus at the University of Edinburgh in Scotland. Englert, 80, is a professor emeritus at Universite Libre de Bruxelles in Belgium.

The prize was announced at 5:45 a.m. CDT on Tuesday, Oct. 8, 2013.

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SMU is a nationally ranked private university in Dallas founded 100 years ago. Today, SMU enrolls nearly 11,000 students who benefit from the academic opportunities and international reach of seven degree-granting schools. For more information see www.smu.edu.

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UPI: Cosmic explosions give dark energy clues

Post author By Margaret Allen
Post date March 4, 2013

The international news wire service United Press International has covered the SMU Physics Department’s recent supernovae discoveries. The article, “Cosmic explosions give dark energy clues,” was published Feb. 27. Light from two massive stars that exploded hundreds of millions of years ago recently reached Earth, and each event was identified as a supernova by SMU graduate students in the physics department.

Both supernovae were spotted with the Robotic Optical Transient Search Experiment‘s robotic telescope ROTSE3b, which is now operated by SMU graduate students. ROTSE3b is at the McDonald Observatory in the Davis Mountains of West Texas near Fort Davis.

The Central Bureau for Astronomical Telegrams of the International Astronomical Union officially designated the discoveries as Supernova 2013X and Supernova 2012ha.

Ferrante and Dhungana made both discoveries as part of an international collaboration of physicists from nine universities. Everest and Sherpa were discovered with a fully automated, remotely controlled robotic telescope at the University of Texas’ McDonald Observatory. The discovery is a first for the SMU collaboration members.

See the article.

EXCERPT:

DALLAS, Feb. 27 (UPI) — Light from exploding stars is improving the astronomical “yardstick” used to calculate the acceleration of the expansion of the universe, U.S. scientists say.

The light from two supernovae, massive stars that exploded hundreds of millions of years ago, has recently reached Earth, Southern Methodist University researchers said.

A supernova discovered Feb. 6 exploded about 450 million years ago, while a second supernova discovered Nov. 20 exploded about 230 million years ago, Farley Ferrante, an SMU graduate student who made the initial Feb. 6 observation, said.

Both are Type 1a supernovae, the result of white dwarf explosions, he said.

“We call these Type 1a supernovae standard candles,” Ferrante said. “Since Type 1a supernovae begin from this standard process, their intrinsic brightness is very similar. So they become a device by which scientists can measure cosmic distance.”

Type 1a supernova provide astronomers with indirect information about dark energy, which makes up 73 percent of the mass-energy in the universe and is theorized as being responsible for the accelerating expansion of our universe at various times after the Big Bang.

“Every exploding star observed allows astronomers to more precisely calibrate the increasing speed at which our universe is expanding,” Ferrante said. “The older the explosion, the farther away, the closer it was to the Big Bang and the better it helps us understand dark energy.”

See the article.

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ANI News: Exploding stars offer clues to dark energy

Post author By Margaret Allen
Post date March 4, 2013

The Asian news wire service Asian News International has covered the SMU Physics Department’s recent supernovae discoveries. The article, “Exploding stars offer clues to dark energy,” was published Feb. 28. Light from two massive stars that exploded hundreds of millions of years ago recently reached Earth, and each event was identified as a supernova by SMU graduate students in the physics department.

The Central Bureau for Astronomical Telegrams of the International Astronomical Union officially designated the discoveries as Supernova 2013X and Supernova 2012ha.

Read the full article.

EXCERPT:

Washington, February 28 (ANI): Observation of two bright exploding stars is improving the astronomical “tape measure” used to calculate the acceleration of the expansion of the universe, say scientists.

Light from two massive stars that exploded hundreds of millions of years ago recently reached Earth, and each event was identified as a supernova, Southern Methodist University scientists said.

A supernova discovered Feb. 6 exploded about 450 million years ago, said Farley Ferrante, a graduate student at Southern Methodist University, Dallas, who made the initial observation.

The exploding star is in a relatively empty portion of the sky labeled “anonymous” in the faint constellation Canes Venatici. Home to a handful of galaxies, Canes Venatici is near the constellation Ursa Major , best known for the Big Dipper.

A second supernova discovered Nov. 20 exploded about 230 million years ago, said Ferrante, who made the initial observation. That exploding star is in one of the many galaxies of the Virgo constellation.

Both supernovae were spotted with the Robotic Optical Transient Search Experiment’s robotic telescope ROTSE3b, which is now operated by SMU graduate students. ROTSE3b is at the McDonald Observatory in the Davis Mountains of West Texas near Fort Davis.

The supernova that exploded about 450 million years ago is officially designated Supernova 2013X. It occurred when life on Earth consisted of creatures in the seas and oceans and along coastlines. Following naming conventions for supernova, Supernova 2013X was nicknamed “Everest” by Govinda Dhungana, an SMU graduate student who participated in the discovery.

The supernova that exploded about 230 million years ago is officially designated Supernova 2012ha. The light from that explosion has been en route to Earth since the Triassic geologic period, when dinosaurs roamed the planet.

“That’s fairly recent as these explosions go,” Ferrante said.

Dhungana gave the nickname “Sherpa” to Supernova 2012ha.

Everest and Sherpa are two of about 200 supernovae discovered worldwide in a given year, according to the scientists.

“Everest and Sherpa aren’t noteworthy for being the youngest, oldest, closest, furthest or biggest supernovae ever observed. But both, like other supernovae of their kind, are important because they provide us with information for further science,” Ferrante said.

Read the full article.

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redOrbit: Astronomers Discover White Dwarf Supernovae

Post author By Margaret Allen
Post date March 1, 2013

The news web site redOrbit has covered the SMU Physics Department’s recent supernovae discoveries. The article, “Astronomers Discover White Dwarf Supernovae,” was published Feb. 27. Light from two massive stars that exploded hundreds of millions of years ago recently reached Earth, and each event was identified as a supernova by SMU graduate students in the physics department.

The Central Bureau for Astronomical Telegrams of the International Astronomical Union officially designated the discoveries as Supernova 2013X and Supernova 2012ha.

Read the full article.

EXCERPT:

By Lee Rannals
redOrbit.com
White dwarf supernovae that occurred millions of years ago have popped up in the Virgo Cluster galaxy and part of the sky labelled as “anonymous.”

Southern Methodist University (SMU) researchers say they’ve confirmed two bright stars that showed up in our skies in February and November are supernovae. Supernovae are the result of stars that have reached the end of their life, resulting in a large explosion that can consume anything in its path.

In November, Farley Ferrante, a graduate student at SMU, made the initial observation of a supernova, Supernova 2012ha or “Sherpa,” that derived from the Virgo constellation, about 230 million light years away. Another supernova, Supernova 2013X or “Everest,” was discovered on February 6, sitting 450 million years away in a part of the sky labeled “animus” near the faint constellation Canes Venatici.

“Everest and Sherpa aren’t noteworthy for being the youngest, oldest, closest, furthest or biggest supernovae ever observed,” Ferrante said. “But both, like other supernovae of their kind, are important because they provide us with information for further science.”

Both supernovae are considered Type 1a, which are the result of white dwarf explosions. A white dwarf star has a mass comparable to that of the Sun and its core is a comparable size to that of the Earth. According to Robert Kehoe, physics professor and leader of the SMU astronomy team in the SMU Department of Physics, a teaspoon of a white dwarf star would weigh about as much as Mount Everest.

When a white dwarf heads towards the end of its life, it grows to about one and a half times the size of the sun and eventually collapses and explodes, resulting in a Type 1a supernova.

“We call these Type 1a supernovae standard candles,” Ferrante said. “Since Type 1a supernovae begin from this standard process, their intrinsic brightness is very similar. So they become a device by which scientists can measure cosmic distance. From Earth, we measure the light intensity of the exploded star. As star distances from Earth increase, their brilliance diminishes.”

Read the full article.

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White dwarf supernovae are discovered in Virgo Cluster galaxy and in sky area “anonymous”

Post author By Margaret Allen
Post date February 26, 2013

Observation of two bright exploding stars improves the astronomical “tape measure” that scientists use to calculate the acceleration of the expansion of the universe

Light from two massive stars that exploded hundreds of millions of years ago recently reached Earth, and each event was identified as a supernova.

A supernova discovered Feb. 6 exploded about 450 million years ago, said Farley Ferrante, a graduate student at Southern Methodist University, Dallas, who made the initial observation.

The exploding star is in a relatively empty portion of the sky labeled “anonymous” in the faint constellation Canes Venatici. Home to a handful of galaxies, Canes Venatici is near the constellation Ursa Major, best known for the Big Dipper.

Reidus hilli, John Graf, SMU, coelacanth, Dipluridae,

A second supernova discovered Nov. 20 exploded about 230 million years ago, said Ferrante, who made the initial observation. That exploding star is in one of the many galaxies of the Virgo constellation.

The supernova that exploded about 450 million years ago is officially designated Supernova 2013X. It occurred when life on Earth consisted of creatures in the seas and oceans and along coastlines. Following naming conventions for supernova, Supernova 2013X was nicknamed “Everest” by Govinda Dhungana, an SMU graduate student who participated in the discovery.

The supernova that exploded about 230 million years ago is officially designated Supernova 2012ha. The light from that explosion has been en route to Earth since the Triassic geologic period, when dinosaurs roamed the planet. “That’s fairly recent as these explosions go,” Ferrante said. Dhungana gave the nickname “Sherpa” to Supernova 2012ha.

Type 1a supernovae help measure cosmic distances
Everest and Sherpa are two of about 200 supernovae discovered worldwide in a given year. Before telescopes, supernovae observations were rare — sometimes only several every few centuries, according to the scientists.

“Everest and Sherpa aren’t noteworthy for being the youngest, oldest, closest, furthest or biggest supernovae ever observed,” Ferrante said. “But both, like other supernovae of their kind, are important because they provide us with information for further science.”

Everest and Sherpa are Type 1a supernovae, the result of white dwarf explosions, said Robert Kehoe, physics professor and leader of the SMU astronomy team in the SMU Department of Physics.

The scientists explain that a white dwarf is a dying star that has burned up all its energy. It is about as massive as the Earth’s sun. It’s core is about the size of the Earth. The core is dense, however, and one teaspoon of it weighs as much as Mount Everest, Kehoe said.

A white dwarf explodes if fusion restarts by tugging material from a nearby star, according to the scientists. The white dwarf grows to about one and a half times the size of the sun. Unable to support its weight, Kehoe said, collapse is rapid, fusion reignites and the white dwarf explodes. The result is a Type 1a supernova.

“We call these Type 1a supernovae standard candles,” Ferrante said. “Since Type 1a supernovae begin from this standard process, their intrinsic brightness is very similar. So they become a device by which scientists can measure cosmic distance. From Earth, we measure the light intensity of the exploded star. As star distances from Earth increase, their brilliance diminishes.”

While Sherpa is a standard Type 1a, Everest is peculiar. It exhibits the characteristics of a Type 1a called a 1991T, Ferrante said.

“Everest is the result of two white dwarfs that collide, then merge,” he said.

The brightness of Sherpa’s explosion was a magnitude 16, which is far dimmer than can be seen with the naked eye. Everest’s explosion was even dimmer, a magnitude 18.

For perspective, light travels 5.88 trillion miles in a year. The sun is 93 million miles from Earth, so light from the sun reaches Earth in eight minutes.

Supernovae help in search to understand mysterious dark energy
Like other Type 1a supernovae, Everest and Sherpa provide scientists with a tiny piece to the puzzle of one of the greatest mysteries of the universe: What is dark energy?

Every Type 1a supernova provides astronomers with indirect information about dark energy, which makes up 73 percent of the mass-energy in the universe. It’s theorized that dark energy explains the accelerating expansion of our universe at various epochs after the Big Bang.

“Every exploding star observed allows astronomers to more precisely calibrate the increasing speed at which our universe is expanding,” Ferrante said. “The older the explosion, the farther away, the closer it was to the Big Bang and the better it helps us understand dark energy.”

Hobby-Eberly spectrogram confirms discovery of supernovae
Everest’s discovery was confirmed by a spectrogram obtained Feb. 10 with the Hobby-Eberly Telescope, also at McDonald Observatory. Everest is located in a host galaxy identified as 2286144 in the Principal Galaxies Catalog.

A spectrogram obtained Nov. 29 with the Hobby-Eberly Telescope confirmed Sherpa’s discovery in one of the many galaxies of the Virgo Cluster.

The Central Bureau for Astronomical Telegrams of the International Astronomical Union officially designated the discoveries as Supernova 2013X and Supernova 2012ha.

The telescope, ROTSE, constantly scans the skies for any significant changes, such as supernovae, novae and variable stars. Data from the telescope are reviewed daily by Ferrante, Dhungana and other scientists on the team, who search for signs of stellar activity.

Until now, primary responsibility for the management and operation of ROTSE3b was held by the University of Michigan. The SMU team took over that responsibility starting in Fall 2012. The ownership transfer will be completed by summer 2013, said SMU’s Kehoe.

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Observed! SMU’s LHC physicists confirm new particle; Higgs ‘God particle’ opens new frontier of exploration

Post author By Margaret Allen
Post date July 4, 2012

Physicists from SMU and around the globe were euphoric Wednesday with the revelation that a new particle consistent with the Higgs boson “God particle” has been observed.

Described as a great triumph for science, the observation is the biggest physics discovery of the last 50 years and opens what scientists said is a vast new frontier for more research.

The achievement is the result of the global CERN scientific collaboration of thousands of scientists, including physicists from SMU, and CERN’s massive $10 billion Large Hadron Collider proton smasher.

“The observation opens up clear directions for physicists at SMU and throughout the world to study the properties of the Higgs,” said SMU physicist Ryszard Stroynowski, a principal investigator in the search for the Higgs and the leader of SMU’s team from the Department of Physics on the experiment.

“The experimental physics group at SMU has been involved since 1994 and is a major contributor to this study. This discovery was many years in the making, but it was worth the wait,” Stroynowski said.

The results, which are preliminary, were announced at CERN, the European Organization for Nuclear Research, near Geneva, Switzerland, and at the International Conference of High Energy Physics in Melbourne, Australia.

SMU Dean of Dedman College of Humanities and Sciences William M. Tsutsui noted that the crucial work contributed by SMU scientists gives Dallas standing in the discovery.

“Although the world’s eyes are on Switzerland, it is important to remember how much of the expertise driving the revolutionary experiments at CERN came from right here in Dallas,” Tsutsui said. “Distinguished scholars in Dedman College’s Department of Physics, including Ryszard Stroynowski and Jingbo Ye, have played critical roles in the search for the tiniest and most elusive building blocks of the universe.”

Observation is culmination of nearly 50 years of research
In making the announcement, CERN’s scientists stopped short of declaring the new particle the Higgs, saying they will further analyze the data to see whether it is the Higgs boson as originally theorized more than 40 years ago, but which has never been observed through experiments.

A Higgs particle is necessary to round out the fundamental particles that make up physics’ Standard Model, which describes the fundamental particles and their interactions.

Without a Higgs, the Standard Model does not fully explain how the universe emerged from the Big Bang. The Higgs explains how matter acquires mass.

CERN’s Large Hadron Collider along the border of France and Switzerland made it possible to observe evidence of the Higgs by smashing together protons at high energies so their breakup replicates the Big Bang. The LHC, which took a decade to build, started operation in 2010. It is home to the largest high-energy physics experiments in the world, including the ATLAS and CMS particle detectors, which supplied the data for Wednesday’s results.

Scientists from 45 collaborating nations work on the LHC experiments, including more than 1,700 from 89 U.S. universities. They have helped design, build and operate the LHC accelerator and its particle detectors.

LHC’s data equivalent to grains of sand needed to fill Olympic-size pool
The LHC is a 17-mile tunnel some 100 meters below ground. Within the tunnel, billions of protons are sent hurling into one another to re-create the high-energy explosions present at the Big Bang. In those rare instances when protons collide in the LHC tunnel, the smashing protons break up into smaller particles. In a process akin to reverse engineering, the resulting particle sprays are captured as data that are then analyzed for evidence that they emerged from the fundamental Higgs.

In announcing the results, CERN scientists said data taken the past two years represent 500 trillion collisions. That equates to the grains of sand it would take to fill an Olympic-size swimming pool. Within that data, evidence pointing to the Higgs equals an amount of sand covering the tip of a finger, they said.

Discovery made possible by global supercomputing grid that includes SMU
Credit for the discovery goes not only to the scientists and to CERN’s Large Hadron Collider, but also to a vast worldwide computing grid at partnering institutions. Physicists rely on supercomputers to assist their analysis of the massive flow of raw data containing the Higgs.

The SMU High-Performance Computing system is part of that grid and routinely runs data that contributed to the observation, Stroynowski said.

“Much of the success of our small group in the highly competitive environment of a large international collaboration has been due to an easy access and superb performance of the SMU High Performance Computing system,” Stroynowski said. “We used the HPC for fast data analyses and complex calculations needed for the discovery.”

Discovery of the new particle demonstrates the importance of basic research, said James Quick, associate vice president for research at SMU and dean of graduate studies.

“SMU is proud and excited that its Department of Physics has been an active participant in this effort and looks forward to the department’s continued participation at CERN,” he said. “Launched by a federal research project sponsored by Congressman Pete Sessions, high-performance computing at SMU played a role in the Higgs discovery and is a primary focus in the university’s drive to expand research and enhance education.”

Discovery is once-in-a-lifetime milestone for SMU researchers
SMU researchers contribute to the experiment through hardware and software development, as well as by taking operations shifts, both in the control room and in the United States, by remote, and through review of their colleagues’ work.

Besides Stroynowski, the SMU team includes Physics Department researchers Jingbo Ye, Ryan Rios and Julia Hoffman. In addition, physics faculty Robert Kehoe and Stephen Sekula are part of the SMU team. Theoretical faculty include Pavel Nadolsky and Fredrick Olness.

“It’s a very happy day for all of us in particle physics,” said Nadolsky, who with other physicists contributed calculations extensively used by LHC experimentalists, including for discovery of the Higgs boson candidate and for ongoing analyses to establish the properties of the new particle. Those working with him include postdoctoral researchers Marco Guzzi and Jun Gao, graduate student Zhihua Liang, and senior lecturer Simon Dalley.

Other researchers who have participated on the SMU team include Ana Firan, Haleh Hadavand, Sami Kama, Aidan Randle-Conde, Peter Renkel, Rozmin Daya, Renat Ishmukhametov, Tingting Cao and Kamile Dindar-Yagci.

Electronics development was carried out by research professors Andy Liu and Annie Xiang, with computer support by Justin Ross.

“The discovery of the Higgs is a once-in-a-lifetime event; this is the culmination of a 50-year quest,” said Olness, chair of the SMU Physics Department. “The last time a discovery of this import occurred was in 1983 with the observation of the W and Z boson — also at CERN; this achievement was recognized with the 1984 Nobel Prize. Many speculate the discovery of the Higgs boson also merits a Nobel Prize.”

The vast majority of U.S. scientists participate in the LHC experiments from their home institutions, remotely accessing and analyzing the data through high-capacity networks and grid computing.

“The results released on July 4 are truly a ‘team effort,’ not just by SMU but throughout all of ATLAS,” said Sekula, assistant physics professor. “These results are not possible without both the cooperation and competition that are needed to drive scientific innovation and progress.”

Waiting for Higgs for more than half a century
Physicists theorized in 1964 the existence of a new particle, now known as the Higgs, whose coupling with other particles would determine their mass.

SMU’s Kehoe said the observation changes our view of the universe. “It further transforms our daily experience of mass, which is hard and heavy, into the ghostly world of quantum mechanical interactions,” Kehoe said. “If what we are seeing is the Higgs particle, we will have identified the last unknown particle in the Standard Model.”

The Standard Model of particle physics has proved to explain correctly the elementary particles and forces of nature through more than four decades of experimental tests. But it cannot, without the Higgs boson, explain how most of these particles acquire their mass, a key ingredient in the formation of our universe.

CERN reported that both the ATLAS and CMS experiments within the LHC independently observed the new heavy particle in the mass region around 125-126 billion electron volts.

“So far, more than one study indicates an excess, but by a bit more than expected,” Kehoe said. “And the mass is in the range predicted for a Standard Model Higgs. However, measurements from other analyses need also to be brought to bear.”

The preliminary results announced Wednesday are based on data collected in 2011 and 2012, with the 2012 data still under analysis. A more complete picture will emerge later this year after the LHC provides more data.

Scientists to gather more data to learn about new particle
Sekula, who was at CERN and live-blogged Wednesday’s announcement, reported that “the atmosphere in the Main Amphitheater at CERN was electric, and all this energy burst forth in thunderous applause when first CMS, then ATLAS, showed independent and overwhelming evidence for the existence of a new particle in nature, consistent with the Higgs particle. Decades of scientific hope and frustration suddenly turned to joy and excitement — I can only imagine what the future holds as we gather more data and learn more about this particle.”

The CMS and ATLAS experiments in December announced seeing tantalizing hints of a new particle in their hunt for the Higgs. Since resuming data-taking in March 2012, the CMS and ATLAS experiments have more than doubled their collected data.

In the future, physicists will have to determine the properties of the new particle.

“How much does it weigh precisely? What are its quantum mechanical properties?” Kehoe said. “There are several theories that are consistent with what we’ve seen so far, like the theory of supersymmetry, and we need to make careful measurements to tell which one is correct. If what we’re seeing is a new type of particle that only superficially resembles the Higgs right now, then this will revolutionize our understanding of matter and energy at a fundamental level.” — Margaret Allen, CERN, Fermilab

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SMU has an uplink facility located on campus for live TV, radio, or online interviews. To speak with an SMU expert or book an SMU guest in the SMU Broadcast Studio, call SMU News & Communications at 214-768-7650.

Tags Aidan Randle-Conde, Dedman College, Fredrick Olness, Jingbo Ye, Julia Hoffman, Pavel Nadolsky, Robert Kehoe, Ryan Rios, Ryszard Stroynowski, Stephen J. Sekula

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Fermilab: Tevatron experiments report latest results in search for Higgs boson

Post author By Margaret Allen
Post date March 7, 2012

Using different search techniques, Tevatron physicists see hints of Higgs boson sighting consistent with those from LHC

Book a live interview

To book a live or taped interview with Robert Kehoe in the SMU News Broadcast Studio call News and Communications at 214-768-7650 or email news@smu.edu.

Book a live interview

To book a live or taped interview with Fredrick Olness in the SMU News Broadcast Studio call SMU News at 214-768-7650 or email news@smu.edu.

The Quest for the Higgs Boson

“It doesn’t matter how beautiful your theory is, it doesn’t matter how smart you are. If it doesn’t agree with experiment, it’s wrong.” — physicist Richard Feynman

By Fredrick Olness
Chairman and Professor
SMU Department of Physics
A 50 year search for the origin of particle mass nears an end. Maybe.

Mass is a seemingly simple property of everyday objects — atoms, humans, coffee cups. Yet, to understand the origin of mass on a fundamental level has been a challenging problem with a long history. The solution to this problem, suggested nearly 50 years ago, was the Higgs Boson (or just Higgs, for short). However, it has yet to be discovered.

On Wednesday, March 7, 2012, an end to the Higgs search appeared much closer when the Fermi National Accelerator Laboratory in Illinois presented the latest results from two of its experiments, CDF and DZero, in an early morning announcement viewed around the globe on the World Wide Web.

The announcement was a joint presentation by researchers from CDF and DZero, the two large independent experiments at Fermilab, in which they presented evidence for the Higgs based on the results of their data.

Both the CDF and DZero experiments observed evidence for the Higgs. While the evidence was significant, it was not yet sufficient to claim an unambiguous discovery; however, it is quite compelling that the Higgs mass range obtained by these two independent experiments is consistent.

These results represent a tremendous step forward in explaining why fundamental particles have mass, and whether the Higgs exists.

The Fermilab results are similar in statistical significance to those presented in December 2011 by the Large Hadron Collider and Atlas experiments at the CERN particle collider in Europe, which announced that its data indicated hints of the Higgs boson.

What is the Higgs boson?
The postulated Higgs boson is responsible for giving mass to the many fundamental particles that make up the universe. This includes the quarks that comprise protons and neutrons, which comprise atoms and molecules, which comprise humans and everything around them. In essence, the Higgs generates the mass of the fundamental particles that make up you and your coffee cup.

We know objects have mass — just lift a heavy suitcase or weigh yourself on a scale. But to explain this seemingly simple idea in the context of our current fundamental theories has been a struggle ever since the idea of the Higgs was introduced 50 year ago. The problem is that to give particles mass in a straightforward manner would spoil a particular symmetry of the theory known as the “gauge symmetry.” Who cares? you ask, and why should I be worried about symmetry?

Symmetries have been an important guiding aspect of physics dating back before Einstein, who used symmetry principles, in part, to conclude that “all reference frames are created equal,” which led to his Theory of Relativity — certainly one of the triumphs of the 20th Century.

And that is what is so special about the Higgs; it gives particles a mass without violating the rules of symmetry.

How does the Higgs solve the problem?
According to our current understanding, Higgs bosons permeate all of space. As fundamental particles move through space, Higgs bosons interact with the particles and effectively exert a drag on them; it is this drag effect which we interpret as the mass of the particle.

Consider the following experiment. First move your coffee cup through the air, and then repeat this motion underwater; the water provides more resistance on the cup and it “feels more massive” as you drag it through the water as compared to the air. It is the interaction between the water and the coffee cup that provides the resistance to motion of mass. In this analogy, the water is playing the role of the Higgs.

It is the same with a quark, one of the fundamental particles that matter is made from. As a quark moves through space it interacts with the Higgs, and this interaction exerts a drag on the quark so that it “feels heavy.” But this is an illusion; in the strict interpretation of the theory, the quark has “mass” only because of the interaction with the Higgs that simulates the effects of the weight.

DÉJÀ VU: Luminiferous aether
To recap, the current theoretical picture is that Higgs bosons are everywhere. They permeate all space, and they must exist so that fundamental particles (that make up you and your coffee cup) have mass.

Have we seen this situation before?

In the late 1800’s, physicists posited the existence of a “luminiferous aether” which permeated all space. Scientists knew that water waves traveled through water, sound waves through air, and so they believed that light waves also needed something to travel through; luminiferous aether was invented to serve this purpose and get the “right” answer. There were many experiments that gave indirect evidence for the aether; however, all attempts to directly measure it were unsuccessful. Eventually it was demonstrated that the luminiferous aether did not exist, and this paved the way for Einstein to show that it was unnecessary and to present an alternative, his theory of relativity.

Thus, the non-existence of luminiferous aether actually led to more fantastic discoveries than if it had been proven.

Direct vs. indirect evidence
So we come to the central question: does the Higgs exist?

There is ample indirect evidence that the Higgs exists. We know that fundamental particles have mass, and we believe this mass is due to particle interactions with Higgs bosons. Over the past 50 years physicists have performed a variety of sophisticated experiments, and they all point to the existence of the Higgs.

However, in many ways the Higgs is a contrived solution; inelegant, introduced into the theory because so far there has been no better way to get the right answer — that particles have mass.

Just because it is currently the only solution developed does not mean it is the one that nature chooses.

And that is why we need direct evidence of the Higgs; we need to produce an actual Higgs in the laboratory, study its properties, and verify our theoretical view of the world with cold, hard facts from experimental observation.

The 2011 and 2012 results
The LHC and Fermilab experiments are producing these facts and evidence.

If the Higgs is confirmed to exist, it would validate our theory of how particles acquire mass, and serve as the foundation for myriad experiments in the future. Many speculate this discovery would also warrant a Nobel Prize.

If the Higgs is confirmed to not exist, it would likely send many theorists back to the drawing board in hopes of finding that nature has an even more clever mechanism of how particles acquire mass than we have yet been capable of conceiving. And, just as the non-existence of the aether set the stage for relativity, the non-existence of the Higgs could set the stage for future surprises.

Either way it will be an exciting journey and the results from the LHC and Fermilab bring us one step closer to the answer.

Fredrick Olness is a theoretical physicist at SMU studying Quantum Chromodynamics (the fundamental force that binds nuclei) to help answer the questions: What are the fundamental building blocks of nature, and what holds them together?

New measurements announced March 7 by scientists from the CDF and DZero collaborations at the Department of Energy’s Fermi National Accelerator Laboratory indicate that the elusive Higgs boson may nearly be cornered.

After analyzing the full data set from the Tevatron accelerator, which completed its last run in September 2011, the two independent experiments see hints of a Higgs boson.

The new results from Fermilab signify that it’s increasingly difficult to ignore the existence of the Higgs boson, said physicist Robert Kehoe, a professor at Southern Methodist University, who is a scientist on one of the Fermilab experiments that announced the results.

“The Higgs is a fundamental particle theorized about 40 years ago to give matter to the mass that we observe, and which scientists have tried to observe for decades,” Kehoe said. “This is a hint that it exists. It doesn’t establish a discovery. But it lends a little more credence to the theory that there is something there. Anyone trying to say there isn’t a Higgs particle — the data are having a harder time backing that up.”

SMU students who are also participating in the DZero experiment at Fermilab include physics graduate students HuanZhao Liu and Yuriy Ilchenko; SMU postdoctoral researchers Peter Renkel and Amitabha Das; and undergraduate physics student Jason South.

If scientists from CERN and Fermi can confirm in the near future a discovery of the Higgs, that will validate the Standard Model of fundamental particles and interactions, which summarizes current knowledge in particle physics.

“At this point we’ve seen a hint that we may someday observe the long lost Standard Model family member,” said SMU’s Liu.

“No doubt, we live in a very exciting and thrilling historical moment,” said Ilchenko. “The new Higgs results and a promising discovery will not only solve the centuries-old mystery of origin of mass but also highlight a victory of science and the triumph of humanity as a whole.”

Click to read: Frequently asked questions about the Higgs boson.

Data could indicate a Higgs boson with mass similar to CERN data

The Fermilab results are similar in statistical significance to those presented by the Large Hadron Collider at the CERN particle collider in Europe, which in December announced hints of the Higgs boson.

At Fermilab, physicists from the CDF and DZero collaborations found excesses in their data that might be interpreted as coming from a Higgs boson with a mass in the region of 115 to 135 GeV. In this range, the new result has a probability of being due to a statistical fluctuation at level of significance known among scientists as 2.2 sigma. This new result also excludes the possibility of the Higgs having a mass in the range from 147 to 179 GeV.

Physicists claim evidence of a new particle only if the probability that the data could be due to a statistical fluctuation is less than 1 in 740, or three sigmas. A discovery is claimed only if that probability is less than 1 in 3.5 million, or five sigmas.

This result sits well within the stringent constraints established by earlier direct and indirect measurements made by CERN’s Large Hadron Collider, the Tevatron, and other accelerators, which place the mass of the Higgs boson within the range of 115 to 127 GeV. These findings are also consistent with the December 2011 announcement of excesses seen in that range by LHC experiments, which searched for the Higgs in different decay patterns.

Jury still out on confirmation of Higgs
None of the hints announced so far from the Tevatron or LHC experiments, however, are strong enough to claim evidence for the Higgs boson.

“The end game is approaching in the hunt for the Higgs boson,” said Jim Siegrist, DOE Associate Director of Science for High Energy Physics. “This is an important milestone for the Tevatron experiments, and demonstrates the continuing importance of independent measurements in the quest to understand the building blocks of nature.”

Physicists from the CDF and DZero experiments made the announcement at the annual conference on Electroweak Interactions and Unified Theories known as Rencontres de Moriond in Italy. This is the latest result in a decade-long search by teams of physicists at the Tevatron.

“I am thrilled with the pace of progress in the hunt for the Higgs boson. CDF and DZero scientists from around the world have pulled out all the stops to reach this very nice and important contribution to the Higgs boson search,” said Fermilab Director Pier Oddone. “The two collaborations independently combed through hundreds of trillions of proton-antiproton collisions recorded by their experiments to arrive at this exciting result.”

Higgs bosons, if they exist, are short-lived and can decay in many different ways. Just as a vending machine might return the same amount of change using different combinations of coins, the Higgs can decay into different combinations of particles. Discovering the Higgs boson relies on observing a statistically significant excess of the particles into which the Higgs decays and those particles must have corresponding kinematic properties that allow for the mass of the Higgs to be reconstructed.

“There is still much work ahead before the scientific community can say for sure whether the Higgs boson exists,” said Dmitri Denisov, DZero co-spokesperson and physicist at Fermilab. “Based on these exciting hints, we are working as quickly as possible to further improve our analysis methods and squeeze the last ounce out of Tevatron data.”

High-energy particle colliders recreate the Big Bang’s energy
Only high-energy particle colliders such as the Tevatron and LHC can recreate the energy conditions found in the universe shortly after the Big Bang. According to the Standard Model, the theory that explains and predicts how nature’s building blocks behave and interact with each other, the Higgs boson gives mass to other particles.

“Without something like the Higgs boson giving fundamental particles mass, the whole world around us would be very different from what we see today,” said Giovanni Punzi, CDF co-spokesperson and physicist at the National Institute of Nuclear Physics, or INFN, in Pisa, Italy. “Physicists have known for a long time that the Higgs or something like it must exist, and we are eager to finally pin this phenomenon down and start learning more about it.”

If a Higgs boson is created in a high-energy particle collision, it immediately decays into lighter more stable particles before even the world’s best detectors and fastest computers can snap a picture of it. To find the Higgs boson, physicists retraced the path of these secondary particles and ruled out processes that mimic its signal.

The experiments at the Tevatron and the LHC offer a complementary search strategy for the Higgs boson. The Tevatron was a proton/anti-proton collider, with a maximum center of mass energy of 2 TeV, whereas the LHC is a proton/proton collider that will ultimately reach 14 TeV.

Search strategies vary at the two accelerators
Because the two accelerators collide different pairs of particles at different energies and produce different types of backgrounds, the search strategies are different. At the Tevatron, for example, the most powerful method is to search the CDF and DZero datasets to look for a Higgs boson that decays into a pair of bottom quarks if the Higgs boson mass is approximately 115-130 GeV.

It is crucial to observe the Higgs boson in several types of decay modes because the Standard Model predicts different branching ratios for different decay modes. If these ratios are observed, then this is experimental confirmation of both the Standard Model and the Higgs.

“The search for the Higgs boson by the Tevatron and LHC experiments is like two people taking a picture of a park from different vantage points,” said Gregorio Bernardi, DZero co-spokesperson at the Nuclear Physics Laboratory of the High Energies, or LPNHE, in Paris.

“One picture may show a child that is blocked from the other’s view by a tree. Both pictures may show the child but only one can resolve the child’s features,” said Bernardi. “You need to combine both viewpoints to get a true picture of who is in the park. At this point both pictures are fuzzy and we think maybe they show someone in the park. Eventually the LHC with future data samples will be able to give us a sharp picture of what is there. The Tevatron by further improving its analyses will also sharpen the picture which is emerging today.”

Result represents years of work by hundreds of scientists
This new updated analysis uses 10 inverse femtobarns of data from both CDF and DZero, the full data set collected from 10 years of the Tevatron’s collider program. Ten inverse femtobarns of data represents about 500 trillion proton-antiproton collisions. Data analysis will continue at both experiments.

“This result represents years of work from hundreds of scientists around the world,” said Rob Roser, CDF co-spokesperson and physicist at Fermilab. “But we are not done yet – together with our LHC colleagues, we expect 2012 to be the year we know whether the Higgs exists or not, and assuming it is discovered, we will have first indications that it behaves as predicted by the Standard Model.”

CDF is an international experiment of 430 physicists from 58 institutions in 15 countries . DZero is an international experiment conducted by 446 physicists from 82 institutions in 18 countries . Funding for the CDF and DZero experiments comes from DOE’s Office of Science, the National Science Foundation, and a number of international funding agencies. — Fermilab and Southern Methodist University

Frequently Asked Questions About the Higgs Boson
Why should the average person care if the Higgs is found?
Understanding more about the building blocks of matter and the forces that control their interactions helps scientists to learn how to manipulate those forces to humankind’s benefit.

For example, the study of the electron led to the development of electricity, the study of quantum mechanics made possible the creation of GPS systems and the study of the weak force led to an understanding of radioactive decay and nuclear power.

Now what?
The Tevatron experiments will continue to further analyze the Higgs boson data to wring out more information. In addition, the Tevatron and LHC experiments are working to combine their data for a release at an unspecified date.

Even if both teams find evidence of a Higgs boson in the same location, physicists will need to do more analysis to make sure the Higgs boson isn’t a non-Standard Model Higgs masquerading as a resident of the Standard Model. That will require physicists to measure several properties in addition to mass.

What would finding the Higgs boson mean for the field of physics?
Finding evidence of the Higgs boson would expand the following three areas of study:

Pin-pointing the mass range of the Higgs would help physicists condense the number of theories about the existence of undiscovered particles and the forces that interact on them. For example, a Standard Model Higgs boson would rule out classic QCD-like versions of technicolor theory.
A Higgs boson with a mass larger than 125 GeV would rule out the simplest versions of supersymmetry, or SUSY, which predict that every known particle has an unknown sibling particles with a different mass. Other theories would gain more support. One such SUSY theory predicts that a Standard Model Higgs boson would appear as the lightest of a group of five or more Higgs bosons. Whether the Higgs boson exists or not does not affect theories about the existence of extra dimensions.

Knowing the mass of the Higgs boson would give physicists more data to plug into other equations about how our universe formed and about some of the least understood particle interactions, such as magnetic muon anomaly.

Finding evidence of a heavy mass Higgs boson (larger than 150 GeV) would require the existence of undiscovered particles and/or forces. Finding a light mass Higgs boson (less than 125 GeV) would not require the existence of new physics but doesn’t rule it out either.

SMU has an uplink facility on campus for live TV, radio or online interviews. To speak with an SMU expert or to book them in the SMU studio, call SMU News & Communications at 214-768-7650 or UT Dallas Office of Media Relations at 972-883-4321.

Tags Dedman College, Robert Kehoe, SMU Department of Physics

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Fermilab Today: Top quark mass team wages war on two fronts

Post author By Margaret Allen
Post date January 31, 2012

The research of SMU physicist Robert Kehoe, a professor in the SMU Department of Physics, has been featured by Fermilab Today. The magazine is the official publication of the U.S. Department of Energy’s Fermi National Accelerator Laboratory near Chicago. Fermi is a high-energy particle physics laboratory credited in 1995 with discovery of the fundamental particle, the top quark.

The article, “Top quark mass team wages war on two fronts,” appears in Fermilab Today‘s Jan. 26 edition as the “Result of the Week.”

Kehoe is part of the DZero collaboration of scientists who seek measurements of the top quark to determine the mass of the Higgs boson, another fundamental particle that has never been observed but which theoretical physicists have theorized generates mass for all particles that comprise matter. Others from SMU who were instrumental in the analysis include doctoral student Yuriy Ilchenko and post doctoral researcher Peter Renkel.

The paper “Measurement of the top quark mass in collisions using events with two leptons” was published by Fermilab. It reports DZero has obtained the world’s most precise measurement in the dilepton channel of the top quark mass.

“The measurement precision is now down to 1.6% in these events, which is astounding given how rare dilepton events are,” Kehoe said. “Perhaps more importantly, we have pursued a new way of calibrating these events that dramatically lowered the systematic uncertainty, and will allow it to decrease with more data — we have half the data yet to analyze.”

Read the full story.

EXCERPT:
By Mike Cooke
Fermilab Today

Two major factors contribute to the ultimate precision of a measurement of the top quark mass: the amount of data used to make that measurement and the understanding of the uncertainty introduced by the detector. The amount of data used affects the size of the statistical uncertainty of the measurement, while accounting for the bias of the detector effects leads to the systematic uncertainty. Since the final precision of a measurement can’t be smaller than the larger of these two uncertainties, it is possible to have a measurement that is limited by the systematics. A systematically limited measurement won’t improve by simply taking more data. The most recent top quark mass measurement at DZero succeeded in turning a systematically limited analysis channel into a statistically limited one.

The top quark always decays into a W boson and a bottom quark. The W boson can decay into a neutrino and a charged lepton, such as an electron or muon, or into quarks. The major distinction between top quark pair analysis channels is the number of leptonic W boson decays allowed. In the dilepton channel, both W bosons decay leptonically and two neutrinos are produced. However, the incomplete reconstruction of neutrinos in the DZero detector leads to ambiguity when studying these top quark pair events. To account for this ambiguity, DZero physicists considered all possible values of the neutrino parameters to determine the value of the top quark mass that best fits the DZero data set.

Read the full story.

Tags Dedman College, Peter Renkel, Robert Kehoe, SMU Department of Physics, Yuriy Ilchenko

Energy & Matter Researcher news Student researchers Technology

SMU physicists at CERN find hints of long sought after Higgs boson — dubbed the fundamental “God” particle

Post author By Margaret Allen
Post date December 13, 2011

Subatomic particle can explain why matter has mass

In a giant game of hide and seek, physicists say there are indications they finally may have found evidence of the long sought after fundamental particle called the Higgs boson.

Researchers at Switzerland-based CERN, the largest high-energy physics experiment in the world, have been seeking the Higgs boson since it was theorized in the 1960s.

The so-called “God” particle is believed to play a fundamental role in solving the important mystery of why matter has mass. (article continued below)

“It doesn’t matter how beautiful your theory is, it doesn’t matter how smart you are. If it doesn’t agree with experiment, it’s wrong.” — physicist Richard Feynman

By Fredrick Olness
Chairman and Professor
SMU Department of Physics
A 50 year search for the origin of particle mass nears an end. Maybe.

Mass is a seemingly simple property of everyday objects — atoms, humans, coffee cups. Yet, to understand the origin of mass on a fundamental level has been a challenging problem with a long history. The solution to this problem, suggested nearly 50 years ago, was the Higgs Boson (or just Higgs, for short). However, it has yet to be discovered.

On Tuesday, Dec. 13, 2011, an end to the Higgs search appeared much closer when the CERN Laboratory in Geneva, Switzerland presented the latest results from the Large Hadron Collider (LHC) in a colloquium broadcast around the globe on the World Wide Web.

The announcement was a joint presentation by researchers from ATLAS and CMS, the two largest independent experiments at the LHC, in which they presented evidence for the Higgs based on the results of their 2011 data set.

Both the ATLAS and CMS experiments observed evidence for the Higgs. While the evidence was significant, it was not yet sufficient to claim an unambiguous discovery; however, it is quite compelling that the Higgs mass range obtained by these two independent experiments is consistent.

These results represent a tremendous step forward in explaining why fundamental particles have mass, and whether the Higgs exists.

What is the Higgs boson?
The postulated Higgs boson is responsible for giving mass to the many fundamental particles that make up the universe. This includes the quarks that comprise protons and neutrons, which comprise atoms and molecules, which comprise humans and everything around them. In essence, the Higgs generates the mass of the fundamental particles that make up you and your coffee cup.

We know objects have mass — just lift a heavy suitcase or weigh yourself on a scale. But to explain this seemingly simple idea in the context of our current fundamental theories has been a struggle ever since the idea of the Higgs was introduced 50 year ago. The problem is that to give particles mass in a straightforward manner would spoil a particular symmetry of the theory known as the “gauge symmetry.” Who cares? you ask, and why should I be worried about symmetry?

Symmetries have been an important guiding aspect of physics dating back before Einstein, who used symmetry principles, in part, to conclude that “all reference frames are created equal,” which led to his Theory of Relativity — certainly one of the triumphs of the 20th Century.

And that is what is so special about the Higgs; it gives particles a mass without violating the rules of symmetry.

How does the Higgs solve the problem?
According to our current understanding, Higgs bosons permeate all of space. As fundamental particles move through space, Higgs bosons interact with the particles and effectively exert a drag on them; it is this drag effect which we interpret as the mass of the particle.

Consider the following experiment. First move your coffee cup through the air, and then repeat this motion underwater; the water provides more resistance on the cup and it “feels more massive” as you drag it through the water as compared to the air. It is the interaction between the water and the coffee cup that provides the resistance to motion of mass. In this analogy, the water is playing the role of the Higgs.

It is the same with a quark, one of the fundamental particles that matter is made from. As a quark moves through space it interacts with the Higgs, and this interaction exerts a drag on the quark so that it “feels heavy.” But this is an illusion; in the strict interpretation of the theory, the quark has “mass” only because of the interaction with the Higgs that simulates the effects of the weight.

DÉJÀ VU: Luminiferous aether
To recap, the current theoretical picture is that Higgs bosons are everywhere. They permeate all space, and they must exist so that fundamental particles (that make up you and your coffee cup) have mass.

Have we seen this situation before?

In the late 1800’s, physicists posited the existence of a “luminiferous aether” which permeated all space. Scientists knew that water waves traveled through water, sound waves through air, and so they believed that light waves also needed something to travel through; luminiferous aether was invented to serve this purpose and get the “right” answer. There were many experiments that gave indirect evidence for the aether; however, all attempts to directly measure it were unsuccessful. Eventually it was demonstrated that the luminiferous aether did not exist, and this paved the way for Einstein to show that it was unnecessary and to present an alternative, his theory of relativity.

Thus, the non-existence of luminiferous aether actually led to more fantastic discoveries than if it had been proven.

Direct vs. indirect evidence
So we come to the central question: does the Higgs exist?

There is ample indirect evidence that the Higgs exists. We know that fundamental particles have mass, and we believe this mass is due to particle interactions with Higgs bosons. Over the past 50 years physicists have performed a variety of sophisticated experiments, and they all point to the existence of the Higgs.

However, in many ways the Higgs is a contrived solution; inelegant, introduced into the theory because so far there has been no better way to get the right answer — that particles have mass.

Just because it is currently the only solution developed does not mean it is the one that nature chooses.

And that is why we need direct evidence of the Higgs; we need to produce an actual Higgs in the laboratory, study its properties, and verify our theoretical view of the world with cold, hard facts from experimental observation.

The 2011 LHC results
The LHC experiment is producing these facts and evidence.

If the Higgs is confirmed to exist, it would validate our theory of how particles acquire mass, and serve as the foundation for myriad experiments in the future. Many speculate this discovery would also warrant a Nobel Prize.

If the Higgs is confirmed to not exist, it would likely send many theorists back to the drawing board in hopes of finding that nature has an even more clever mechanism of how particles acquire mass than we have yet been capable of conceiving. And, just as the non-existence of the aether set the stage for relativity, the non-existence of the Higgs could set the stage for future surprises.

Either way it will be an exciting journey and the results from the LHC bring us one step closer to the answer.

Fredrick Olness is a theoretical physicist at SMU studying Quantum Chromodynamics (the fundamental force that binds nuclei) to help answer the questions: What are the fundamental building blocks of nature, and what holds them together?

Thousands of scientists from around the world seek evidence of the Higgs particle through experiments at CERN’s Large Hadron Collider. The researchers analyze a flood of electronic data streaming from the breakup of speeding protons colliding in the massive particle accelerator. Scientists on Tuesday announced in a seminar held at CERN that they’ve found hints of the Higgs.

“Now we have a strong indication, but not yet a confirmation, of a discovery,” said Southern Methodist University physicist Ryszard Stroynowski, the leader of SMU’s team of scientists working on the experiment.

Higgs: Attempting to discover Standard Model’s missing piece
Theorists have predicted that some subatomic particles gain mass by interacting with other particles called Higgs bosons. The Higgs boson is the only undiscovered part of the Standard Model of physics, which describes the basic building blocks of matter and their interactions.

Higgs bosons, if they exist, are short-lived and can decay in many different ways. Just as a vending machine might return the same amount of change using different combinations of coins, the Higgs can decay into different combinations of particles. Discovery relies on observing statistically significant excesses of the particles into which they decay rather than observing the Higgs itself.

“If indeed we are able to confirm sighting of the Higgs in the months ahead, this clearly focuses our future studies,” said Stroynowski, a professor in the SMU Department of Physics. “Now by the middle of next year we’ll know for sure if this particle exists and we can begin to study its properties. This is a very big step in the understanding of particle physics.”

SMU researchers contributed to the results announced Tuesday by CERN
Besides Stroynowski, the SMU team of researchers includes three other Physics Department faculty: Jingbo Ye, Robert Kehoe and Stephen Sekula, six postdoctoral fellows and five graduate students. Main contributions to the new analysis of the data were made by postdoctoral researcher Julia Hoffman and graduate student Ryan Rios.

Others in the department who have contributed include former postdoctoral fellow David Joffe, now an assistant professor at Kennesaw State University, graduate students Renat Ishmukhametov and Rozmin Daya and theoretical faculty Fredrick Olness and Pavel Nadolsky.

Stroynowski, Hoffman, and Rios are among the more than 70 scientists whose work directly contributed to the conference papers reporting the findings, said Olness, a professor and chairman of the SMU Department of Physics.

While thousands of scientists worldwide participated directly and indirectly in the experiments, SMU is one of only a few U.S. universities whose scientists are named among the 70 researchers directly cited on one of the three conference papers.

“Professor Stroynowski has demonstrated extraordinary scientific leadership in keeping our relatively small Department of Physics at SMU engaged in one of the most significant scientific experiments of our time,” said Jim Quick, SMU Associate Vice President for Research.

SMU’s role in the LHC experiments provides SMU students a chance to participate in pioneering discoveries, said Olness.

“SMU students helped build the ATLAS detector, they were in the control room when the experiment started up, and they contributed to the analysis,” he said. “The results presented today are historic, and they will help shape our view of the matter and forces that comprise our universe; SMU students have played a role in this achievement.”

Higgs discovery would confirm decades-old theory

Discovering the type of Higgs boson predicted in the Standard Model would confirm a theory first put forward in the 1960s.

“This year, the LHC has come roaring into the front of the hunt for the Higgs boson and may be poised to either identify it, or refute its existence, in the coming months,” said Robert Kehoe, associate professor in the SMU Department of Physics. “As I like to tell my students learning modern physics, ‘You still live in a world in which we do not know for sure the mechanism breaking the symmetry between electromagnetic and weak interactions. That world may be soon to change forever. We may soon see a truly new thing.’”

Even if the LHC experiments find a particle where they expect to find the Higgs, it will take more analysis and more data to prove it is a Standard Model Higgs, according to CERN researchers. If scientists found subtle departures from the Standard Model in the particle’s behavior, this would point to the presence of new physics, linked to theories that go beyond the Standard Model. Observing a non-Standard Model Higgs, currently beyond the reach of the LHC experiments with the data they’ve recorded so far, would immediately open the door to new physics, said an official statement from CERN.

Results constrain Higgs’ mass to a range more limited than before

In announcing the findings, CERN noted that two experiments at the LHC have nearly eliminated the space in which the Higgs boson could dwell. The ATLAS and CMS experiments see modest excesses in their data that could soon uncover the famous missing piece of the physics puzzle, the scientists said.

The experiments’ main conclusion is that the Standard Model Higgs boson, if it exists, is most likely to have a mass constrained to the range 116-130 giga-electron-volts (GeV) by the ATLAS experiment, and 115-127 GeV by CMS. Tantalizing hints have been seen by both experiments in this mass region, but these are not yet strong enough to claim a discovery.

Both ATLAS and CMS have analyzed several decay channels, and the experiments see small excesses in the low mass region that has not yet been excluded.

Taken individually, none of these excesses is any more statistically significant than rolling a die and coming up with two sixes in a row. What is interesting is that there are multiple independent measurements pointing to the region of 124 to 126 GeV. It’s far too early to say whether ATLAS and CMS have discovered the Higgs boson, but these updated results are generating a lot of interest in the particle physics community.

The experiments revealed the latest results as part of their regular report to the CERN Council, which provides oversight for the laboratory near Geneva, Switzerland.

Experiments in coming months will refine the analysis
More than 1,600 scientists, students, engineers and technicians from more than 90 U.S. universities and five U.S. national laboratories take part in the ATLAS and CMS experiments. The Department of Energy’s Office of Science and the National Science Foundation provide support for U.S. participation in these experiments.

Over the coming months, both the ATLAS and CMS experiments will focus on refining their analyses in time for the winter particle physics conferences in March. The experiments will resume taking data in spring 2012.

Another possibility, discovering the absence of a Standard Model Higgs, would point to new physics at the LHC’s full design energy, set to be achieved after 2014. Whether ATLAS and CMS show over the coming months that the Standard Model Higgs boson exists or not, the LHC program is closing in on new discoveries. — CERN, Southern Methodist University

SMU is a member of the ATLAS experiment at the LHC. It takes a large team of scientists to search for the Higgs and other new physics; the SMU delegation includes faculty members Ryszard Stroynowski, Jingbo Ye, Robert Kehoe, Stephen Sekula, and a number of research professors, postdoctoral fellows and graduate students.

In addition, recent SMU ATLAS contributors include postdoctoral fellows Julia Hoffman, David Joffe (now at Kennesaw State), Ana Firan, Haleh Hadavand, Sami Kama, Aidan Randle-Conde and Peter Renkel, and graduate students Ryan Rios, Rozmin Daya, Renat Ishmukhametov Tingting Cao and Kamile Dindar-Yagci. Theoretical support was provided by faculty member Pavel Nadolsky, electronics development by research professors Andy Liu and Annie Xiang, and computer support by Justin Ross.

Tags Annie C. Xiang, Dedman College, Fredrick Olness, Jingbo Ye, Julia Hoffman, Pavel Nadolsky, Robert Kehoe, Ryan Rios, Ryszard Stroynowski, SMU Department of Physics, Stephen J. Sekula

Energy & Matter Researcher news

Hunt for Higgs boson: Mass of top quark narrows search

Post author By Sarah Hanan
Post date December 3, 2009

New high-energy particle research by a team working with data from Fermi National Accelerator Laboratory further heightens the uncertainty about the exact nature of a key theoretical component of modern physics — the massive fundamental particle called the Higgs boson.

Analysis of data from particle collisions resulting in two leptons helps improve measurements of the mass of another heavy subatomic particle called the top quark, says physicist Robert Kehoe at SMU, who led the team that calculated the measurement.

Improving the measurement of the mass of the top quark bears on the nature of the Higgs, says Kehoe, an assistant professor in SMU’s Department of Physics.

The Higgs was postulated in the 1960s to help explain how basic elements of the universe fit together and interact. It is responsible for a phenomenon called the Higgs mechanism, which gives mass to the fundamental particles of nature.

Physicists have searched for more than four decades to observe the never-before-seen Higgs. Now they hope it will be observed in the next few years since data started flowing recently from the world’s newest and largest high-energy particle accelerator, the CERN laboratory’s Large Hadron Collider near Geneva, Switzerland.

Physicists theorize that the top quark — because of its sizable mass — is sensitive to the Higgs and therefore may point to it. They theorize that knowing the mass of the top quark narrows the range of where the Higgs will be detected in CERN’s LHC collisions. The top quark is one of 16 species of subatomic particles that physicists have observed. It was predicted in the 1970s and observed in 1995. Increasingly precise measurements of its mass have been achieved almost every year since, and physicists closely watch the incremental measurements of the top quark.

The two-lepton analysis by Kehoe and SMU post-doctoral researcher Peter Renkel looked at data taken over four years during high-energy collisions at Fermilab, a Department of Energy proton-antiproton collider in Batavia, Ill.

The two-lepton analysis is one of almost a dozen analyses of the mass of the top quark at a Fermilab experiment called “DZero.” The DZero experiment involves 500 physicists and is one of Fermilab’s two large experimental collaborations of scientists. The top quark mass was first observed simultaneously by these two experiments. Several measurements of the top quark’s mass from these two experiments are combined to a “world average” value.

The two-lepton analysis contributed to the latest world average measurement. The analysis looked at particles resulting from smashing protons that break apart and disintegrate. The events are very rare, and the detector can’t see two of the important “ghost” particles — neutrinos — produced by the collision. However, the two leptons are well-measured events and are not seen in other “background” collisions where top quarks are not produced. This allows a rapidly improving precision to be achieved.

The two-lepton research was published in November in the article “Measurement of the top quark mass in final states with two leptons” in “Physical Review D,” the American Physical Society’s journal of particles, fields, gravitation and cosmology. SMU physicists collaborated on the research with scientists at Boston University. The SMU portion of the work was funded by the Department of Energy.

The new world average is so precise that it constrains more tightly than ever the range of possible measurements for the mass of the Higgs, Kehoe says.

If the Higgs does prove different than currently expected, physicists may have to rework their long-standing theoretical framework, known as the Standard Model. Scientists worldwide are hoping to validate the Standard Model — which has worked well for more than 30 years to explain everything from radioactivity to computer chips — by actually observing the Higgs.

“The new results may be an indication that the Higgs boson has different properties than the Standard Model indicates,” Kehoe says. “It’s very difficult to devise a theory without some mechanism that mimics fairly well the Higgs mechanism. But if the underlying cause of this mechanism is significantly different, that will have a major impact on the fundamentals of the Standard Model. It could point to something deeper than the standard Higgs boson at work, and that is very interesting.”

The Standard Model of Fundamental Particles. Credit: Fermilab

The measured value of the top quark mass may even go beyond constraining the standard Higgs. It may suggest that our current understanding of the Higgs is not correct, he says.

If the Higgs does not show up where the constraints indicate, the top measurement may force consideration of new theoretical possibilities that lie outside the existing Standard Model, Kehoe says.

Previous measurements have put the top quark at almost the mass of a gold atom. The new world average measurement puts the top quark at about 186 times the mass of the proton. While the value has changed only a small amount from previous measurements, the percentage of error on the measurement is progressively smaller, in this case less than 1 percent.

“If we make a precise prediction of where the Higgs is and it’s not there, then something is wrong. We’ve just found a major flaw in the model,” says Kehoe, whose work has focused for 16 years on the top quark, including as a graduate student on DZero working directly on the discovery analysis. “It would tell us that the model is oversimplified and that reality is much more complicated.” — Margaret Allen

Tags CERN, Dedman College, Robert Kehoe, SMU Department of Physics

Energy & Matter

Before God particle, scientists must learn soul of new machine

Post author By Margaret Allen
Post date May 20, 2009

After a huge success in first testing, followed by a very public meltdown last September, the Large Hadron Collider may be ready for action again as early as June.

But before the science can proceed, the world’s scientists must come to terms with the complex organism they have created, says one project manager.

“We will have to understand the detector first,” says Ryszard Stroynowski, chair and professor of physics at SMU.

Stroynowski is U.S. Coordinator for the Liquid Argon Calorimeter, the literal and experimental heart of ATLAS, the largest particle detector in the LHC array.

Pictured right: Work progressing in the LHC tunnel.
Photo courtesy of CERN.

The first priority for operation of the ATLAS detector is “to get all those billions of elements to work together in synch again,” Stroynowski says. “We want to see during the summer whether the circulating beam will induce any noise in the system.”

Stroynowski leads an SMU delegation that includes Fredrick Olness, professor of physics, and Robert Kehoe and Jingbo Ye, assistant professors of physics, all in Dedman College. Kehoe is currently at CERN for his research.

The SMU team is focusing on three projects in parallel:

improvements of the graphic and software interfaces for control and monitoring of the detector and of the quality of its data
preparation of the software packages to analyze the data
design and prototyping of the modifications of the readout electronics that will be needed for future upgrades of the experiment to much higher-intensity beams — a six-year research and development project led by Jingbo Ye in SMU’s Physics Electronics Lab.

The LHC is considered the world’s largest physics experiment. The particle accelerator is a 27-kilometer circular tunnel that lies 100 meters underground near Geneva on the French-Swiss border. It uses a magnetic field to propel high-energy protons into each other.

A mechanical failure in September 2008 damaged 53 of the super-sized magnets that power and focus the accelerator’s beams. The final replacement magnet was lowered into place April 30. Repairs in the tunnel now focus on connecting the magnets together and installing new safety and monitoring systems to prevent similar incidents from happening again.

In addition, the 37 damaged magnets that were replaced by spares will be refurbished to serve as spares themselves. Sixteen magnets sustained only minimal damage and were repaired and reinstalled.

The earlier malfunction has resulted in a frustrating wait — one that has had a “rather demoralizing” effect on the students and postdoctoral fellows whose time at the LHC may come and go during downtime, Stroynowski says. Yet the importance of protecting the vast high-energy array from future trauma can’t be overstated, and “the goal is worth the wait, as the payoff may be enormous,” he says.

Scientists and technicians at the European Organization for Nuclear Research — called by its acronym, CERN — in Geneva have maintained an aggressive rehabilitation schedule. The ATLAS detector itself was closed on May 5, marking an end to checks and re-checks of the electronics, cables and other connections. Repairs to the accelerator’s underground ring are scheduled to be completed at the end of May.

Beams will start in June, initially at a relatively low 450 gigaelectron volts (GeV) per beam to ensure the integrity of the new parts and connections. Scientists will raise the energy over a couple of days to 2 teraelectron volts (TeV) per beam, and finally to the LHC’s target operational level of 5 TeV per beam.

The ATLAS team will start taking shifts in July and expects to have useful data starting in October 2009, Stroynowski says. The LHC will then run continuously for 11 months.

Stroynowski says he doesn’t expect any major discoveries by this time next year, but that he hopes “significant results” will come early in 2011.

The LHC’s proton collisions release even smaller pieces of matter, and the Atlas particle detector helps measure the tracks they leave. The huge, international project is directed at finding the “Higgs boson,” a subatomic “God particle” that physicists believe could help explain the origin of our Universe.

The theory behind the Higgs boson holds that all particles had no mass just after the “Big Bang.” As the Universe cooled and the temperature fell below a critical value, an invisible force field composed of subatomic particles called the “Higgs boson” developed throughout the cosmos. Particles that interact with the field gain mass and particles that never interact have no mass. But the theory remains unproven because no one has ever seen the Higgs boson at work. — Kathleen Tibbetts

SMU has an uplink facility on campus for live TV, radio or online interviews. To speak with Dr. Stroynowski or to book him in the SMU studio, call SMU News & Communications at 214-768-7650 or UT Dallas Office of Media Relations at 972-883-4321.

SMU is a private university in Dallas where nearly 11,000 students benefit from the national opportunities and international reach of SMU’s seven degree-granting schools. For more information see www.smu.edu.

Tags CERN, Dedman College, Fredrick Olness, Jingbo Ye, Robert Kehoe, Ryszard Stroynowski, SMU Department of Physics

Energy & Matter

Proton-smasher’s awaited flood of data creates big job for SMU researchers

Post author By Margaret Allen
Post date August 3, 2008
1 Comment on Proton-smasher’s awaited flood of data creates big job for SMU researchers

At 10 p.m. on a Saturday night in April, a handful of SMU scientists continue working at the European Organization for Nuclear Research, called by its acronym CERN, in Geneva, Switzerland. A scattering of lights illuminates the windows in several buildings along the Rue Einstein, where researchers from dozens of countries and hundreds of institutions are combining their expertise on the Large Hadron Collider (LHC) — the biggest physics experiment in history.

Ryszard Stroynowski, chair and professor of physics at SMU, points out each building in succession to a group of visitors. “By October, every light in every one of these windows will be on all night,” he says.

By then, the LHC is expected to be fully tested and ready to work. When the largest particle accelerator ever constructed becomes fully operational, it will hurl protons at one another with precision to a fraction of a micron and with velocities approaching the speed of light. These conditions will allow physicists to recreate and record conditions at the origin of the universe — and possibly discover the mechanisms that cause particles in space to acquire their differences in mass.

For Stroynowski, who has worked for almost 20 years to help make the experiment a reality, words seem inadequate to capture the anticipation surrounding its imminent activation.

“It is somewhat like that of a 6-year-old kid on Christmas Eve, waiting for Santa Claus,” he says. “The time stretches almost unbearably long.”

The LHC will be the site of several experiments in high-energy physics with high-profile collaborators such as Harvard and Duke and national laboratories including Argonne, Brookhaven, Lawrence Berkeley and Fermilab. None of the experiments is more imposing than ATLAS, one of two general-purpose particle detectors in the LHC array. At about 42 meters long and weighing 7,000 tons, ATLAS fills a 12-story cavern beneath the CERN facilities in Meyrin, Switzerland, just outside Geneva. It is a tight fit: ATLAS overwhelms even the vast space it occupies. A catwalk, not quite wide enough for two people to stand side by side, encircles the device and allows an occasional dizzying view into its works.

Size Matters
The detector’s scale will help to focus and release the maximum amount of energy from each subatomic collision. A series of bar codes on each of its parts ensure that the detector’s components, whether palm-sized or room-sized, are aligned and locked with the perfect precision required for operability. Scientists from 37 countries and regions and 167 institutions participated in its design and construction.

As U.S. coordinator for the literal and experimental heart of the ATLAS detector — its Liquid Argon Calorimeter — Stroynowski is helping to finalize the last details of the detector’s operation in anticipation of the extensive testing, scheduled to begin in August. He leads an SMU delegation that includes Fredrick Olness, professor, and Robert Kehoe and Jingbo Ye, assistant professors in the SMU Department of Physics in Dedman College.

SMU scientists are completing work on the computer software interfaces that will control the device, which measures energy deposited by the flying debris of smashed atoms. A cadre of University graduate students and postdoctoral fellows also is working on data processing for ATLAS’ 220,000 channels of electronic signals, an information stream larger than the Internet traffic of a small country.

An estimated 53,000 visitors crowded the CERN facilities on the organization’s “Day of Open Doors” April 6, eager for a glimpse of the work that CNN International has named one of the “Seven Wonders of the Modern World.”

At the beginning of May, the areas were sealed off in preparation for the first round of testing. Computers will remotely control the ATLAS experiment, which will not be touched by human hands because of the radiation released by the atomic collisions. Safety is the reason for the elaborate lockdown procedure involving more than 80 keys, each coded to a different individual’s biometric data. The system is designed to lock out any use of the device if even one key is unaccounted for.

“ATLAS has been built to run for at least 15 years with no direct human intervention,” Stroynowski says. “It will be as if we have shot it into space.”

Currently, the initial test run is scheduled to begin Sept. 1.

The Waiting Game
Once data start streaming in, the game of expectations management begins. The ATLAS detector will produce a staggering amount of raw information from each collision, and the most useful bits will be few and far between. Out of 40 million events per second, the researchers hope to pinpoint 10 events a year. The challenge seems a little like looking for a needle in a haystack the size of Mars.

“We may get what we’re looking for on the first try, or it may take us three years to find anything we can use,” Stroynowski says. “A big part of our job is to make sure we’re ready when we do.”

Among those entrusted with that task are graduate students and postdoctoral fellows in SMU’s Physics Department, including Rozmin Daya, Kamile Dindar, Ana Firan, Daniel Goldin, Haleh Hadavand, Julia Hoffman, Yuriy Ilchenko, Renat Ishmukhametov, David Joffe, Azeddine Kasmi, Zhihua Liang, Peter Renkel, Ryan Rios and Pavel Zarzhitsky.

“I came to SMU for postdoctoral work specifically because of the department’s involvement in the ATLAS project,” says David Joffe, a native of Canada who received his Ph.D. in physics from Northwestern University. “For particle physicists, being part of this is really a once-in-a-lifetime opportunity.”

For Julia Hoffman, who received her doctorate from Soltans Institute for Nuclear Studies in her native Poland, that opportunity has meant expanding her own horizons.

“I learn new, and I mean really new, things every day,” she says. “Different programming languages, different views on physics analysis. I’m learning how it all works from the inside. I work with students and gain new responsibilities. This kind of experience means better chances to find a permanent position that will be as exciting as this one.”

The SMU group works with formulae based in Monte Carlo methods, the “probabilistic models that use repeated random sampling of vast quantities of numbers” to impose a semblance of order on the chaos created when atoms forcibly disintegrate. Results are highly detailed simulations of known physics that will help make visible the tiny deviations researchers hope to detect when ATLAS begins taking data.

These unprecedented computing challenges also have become an impetus for new SMU research initiatives. James Quick, SMU associate vice president for research and dean of graduate studies, hopes to contain ATLAS’ vast data-processing requirements with a large-capability computing center located on campus.

Quick visited CERN in April to discuss the details with Stroynowski and other key personnel. The proposed center would provide a first-priority data processing infrastructure for SMU physicists and a powerful new resource for researchers in other schools and departments. During the inevitable LHC downtime, as beams are calibrated and software is debugged, the SMU center’s computing power would be available for campus researchers in every field across engineering, the sciences and business.

“The ATLAS experiment presents an opportunity for the University to step up in a big way, and one that will benefit the entire campus,” Quick says.

He envisions a data processing farm of 1,000 central processing units, each connected to an Internet backbone to allow the fastest possible return on SMU’s ATLAS input. Speed and access are the keys, Stroynowski says, paraphrasing Winston Churchill: “The winner gets the oyster, and the runner-up gets the shell.”

Those who have made their careers in high-energy physics are well aware of the stakes involved in the LHC, he adds, and being the first to process certain data could separate a potential Nobel Prize winner from those who will make the same discovery a day late.

As a group, high-energy physicists are accustomed to taking the long view — and for SMU researchers, the long view has been especially helpful. The ghost of the Superconducting Super Collider, which would have made its home in North Texas, still shadows the recent triumphs at CERN.

The SSC brought Stroynowski to the University, and its 1993 demise through congressional defunding was the impetus for the LHC project. The questions haven’t gone away because the experiment has changed venues, Stroynowski says. Yet even now, as the first test nears, his anticipation is tempered by caution.

“I don’t think we’ll get a beam all the way around [the LHC tunnel] on the first try,” he says.

Indeed, the subject of whether scientists will achieve a beam collision during the first tests or after additional calibration has been the subject of a few lively wagers.

“I think we’ll have to wait at least a few more weeks for that milestone,” he adds. “But in this case, I’ll be more than happy to be wrong.” — Kathleen Tibbetts

SMU has an uplink facility on campus for live TV, radio or online interviews. To speak with Dr. Biehl or Dr. D’Mello or to book them in the SMU studio, call SMU News & Communications at 214-768-7650 or UT Dallas Office of Media Relations at 972-883-4321.

Tags CERN, David Joffe, Dedman College, Fredrick Olness, James E. Quick, Jingbo Ye, Robert Kehoe, Ryszard Stroynowski, SMU Department of Physics

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Two high school students collected data until they had what they needed to define their star-to-be as a variable — a star that changes brightness.

Treasures of the night sky: Pairs of stars orbit around each other so closely their outer atmospheres touch, so they dim and brighten.

“You’re looking at things a long time ago in the universe, you can get a sense for the movie of the universe,” said Kehoe. “It’s the evolution of the universe.”

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A star exploded billions of years back, but the light of this explosion has just reached the earth, allowing scientists to peep into the past of the universe

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To put the age of the latest discovery into context, scientists believe the Big Bang occurred 13.81 billion years ago.

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Armed with images of the burst, astronomers can now analyze the data in order to understand more about the structure of the universe at its infancy

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Known as a gamma-ray burst, the intense light captured in the night sky resulted from one of the biggest and hottest explosions in the universe, occurring shortly after the Big Bang.

SMU joins nearly 2,000 physicists from U.S. institutions — including 89 U.S. universities and seven U.S. DOE labs — that participate in discovery experiments

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Observation of two bright exploding stars improves the astronomical “tape measure” that scientists use to calculate the acceleration of the expansion of the universe

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Using different search techniques, Tevatron physicists see hints of Higgs boson sighting consistent with those from LHC

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