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

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

“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

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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.

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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.


By Alison Klesman

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.

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

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.

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.

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.

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

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