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SMU Physicist Explains Significance of Latest Cern Discovery Related to the Higgs Boson

Stephen Sekula says observation of the Higgs particle transforming into bottom quarks confirms the 20th-century recipe for mass

DALLAS (SMU) – Scientists conducting physics experiments at CERN’s Large Hadron Collider have announced the discovery of the Higgs boson transforming, as it decays, into subatomic particles called bottom quarks, an observation that confirms that the “Standard Model” of the universe – the 20th century recipe for everything in the known physical world – is still valid.

This new discovery is a big step forward in the quest to understand how the Higgs enables fundamental particles to acquire mass. Many scientists suspect that the Higgs could interact with particles outside the Standard Model, such as dark matter – the unseen matter that does not emit or absorb light, but may make up more than 80 percent of the matter in the universe.

After several years of work experiments at both ATLAS and CMS – CERN detectors that use different types of technology to investigate a broad range of physics –have demonstrated that 60 percent of Higgs particles decay in the same way. By finding and mapping the Higgs boson interactions with known particles, scientists can simultaneously probe for new phenomena.

SMU played important roles in the analysis announced by CERN Aug. 28, including:

  • Development of the underlying analysis software framework (Stephen Sekula, SMU associate professor of physics was co-leader of the small group that included SMU graduate student Peilong Wang and post-doctoral researcher Francesco Lo Sterzo, that does this for the larger analysis for 2017-2018)
  • Studying background processes that mimic this Higgs boson decay, reducing measurement uncertainty in the final result.

“The Standard Model is the recipe for everything that surrounds us in the world today.  Sekula explained. “It has been tested to ridiculous precision. People have been trying for 30-40 years to figure out where or if the Standard Model described matter incorrectly. Like any recipe you inherit from a family member, you trust but verify. This might be grandma’s favorite recipe, but do you really need two sticks of butter? This finding shows that the Standard Model is still the best recipe for the Universe as we know it.”

Scientists would have been intrigued if the Standard Model had not survived this test, Sekula said, because failure would have produced new knowledge.

“When we went to the moon, we didn’t know we’d get Mylar and Tang,” Sekula said. “What we’ve achieved getting to this point is we’ve pushed the boundaries of technology in both computing and electronics just to make this observation. Technology as we know it will continue to be revolutionized by fundamental curiosity about why the universe is the way it is.

“As for what we will get from all this experimentation, the honest answer is I don’t know,” Sekula said. “But based on the history of science, it’s going to be amazing.”

About CERN

At CERN, the European Organization for Nuclear Research, physicists and engineers are probing the fundamental structure of the universe. They use the world’s largest and most complex scientific instruments to study the basic constituents of matter – the fundamental particles. The particles are made to collide together at close to the speed of light. The process gives the physicists clues about how the particles interact, and provides insights into the fundamental laws of nature. Founded in 1954, the CERN laboratory sits astride the Franco-Swiss border near Geneva.

About SMU

SMU is the nationally ranked global research university in the dynamic city of Dallas.  SMU’s alumni, faculty and nearly 12,000 students in seven degree-granting schools demonstrate an entrepreneurial spirit as they lead change in their professions, communities and the world.

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SMU physicist and her students join national laboratories, other universities in high-stakes hunt for elusive dark matter

The future SuperCDMS SNOLAB experiment will hunt for weakly interacting massive particles (WIMPs), hypothetical components of dark matter. If a WIMP (white trace) strikes an atom inside the experiment's detector crystals (gray), it will cause the crystal lattice to vibrate (blue). The collision will also send electrons (red) through the crystal that enhance the vibrations. (Greg Stewart/SLAC National Accelerator Laboratory)

“One of our major concerns is background particles that can mimic the dark matter signature in our detectors.” — Jodi Cooley

SMU physicist Jodi Cooley is a member of the international scientific team that will use a powerful new tool to understand one of the biggest mysteries of modern physics.

The U.S. Department of Energy has approved funding and start of construction for SuperCDMS SNOLAB, a $34 million experiment designed to detect dark matter.

SuperCDMS will begin operations in the early 2020s to hunt for hypothetical dark matter particles called weakly interacting massive particles, or WIMPs.

“Understanding the nature of dark matter is one of the most important scientific puzzles in particle astrophysics today,” said Cooley, an associate professor of experimental particle physics. “The experiment will have unprecedented sensitivity to dark matter particles that are hypothesized to have very low mass and interact very rarely. So they are extremely challenging to detect. This challenge has required us to develop cutting edge detectors.”

Cooley is one of 111 scientists from 26 institutions in the SuperCDMS collaboration. SMU graduate students on the experiment include Matt Stein (Ph.D. ’18) and Dan Jardin; and also previously Hang Qiu (Ph.D. ’17).

Physicists are searching for dark matter because although it makes up the bulk of the universe it remains a mystery. They theorize that dark matter could be composed of dark matter particles, with WIMPs a top contender for the title.

If dark matter WIMP particles exist, they would barely interact with their environment and fly right through regular matter. However, every so often, they could collide with an atom of our visible world, and dark matter researchers are looking for these rare interactions.

The SuperCDMS experiment will be the world’s most sensitive for detecting the relatively light WIMPs.

Cooley and her students in the SMU Department of Physics have been working with Washington-based Pacific Northwest National Laboratory on the challenge of background control and material selection for the experiment’s WIMP detectors.

Understanding background signals in the experiment is a major challenge for the detection of the faint WIMP signals.

“One of our major concerns is background particles that can mimic the dark matter signature in our detectors,” Cooley said. “As such, the experiment is constructed from radiopure materials that are carefully characterized through a screening and assay before they are selected.”

The SMU research team also has performed simulations of background particles in the detectors.

“Doing this helps inform the design of the experiment shield,” Cooley said. “We want to select the right materials to use in construction of the experiment. For example, materials that are too high in radioactivity will produce background particles that might produce fake dark matter signals in our detectors. We are extremely careful to use materials that block background particles. We also take great care that the material we use to hold the detectors in place — copper — is very radiopure.”

The experiment will be assembled and operated within the existing Canadian laboratory SNOLAB – 6,800 feet underground inside a nickel mine near the city of Sudbury. That’s the deepest underground laboratory in North America.

The experiment’s detectors will be protected from high-energy particles, called cosmic radiation, which can create the unwanted background signals that Cooley’s team wants to prevent.

SuperCDMS SNOLAB will be 50 times more sensitive than predecessor
Scientists know that visible matter in the universe accounts for only 15 percent of all matter. The rest is the mysterious substance called dark matter.

Due to its gravitational pull on regular matter, dark matter is a key driver for the evolution of the universe, affecting the formation of galaxies like our Milky Way. It therefore is fundamental to our very own existence.

The SuperCDMS SNOLAB experiment will be at least 50 times more sensitive than its predecessor, exploring WIMP properties that can’t be probed by other experiments.

The search will be done using silicon and germanium crystals, in which the collisions would trigger tiny vibrations. However, to measure the atomic jiggles, the crystals need to be cooled to less than minus 459.6 degrees Fahrenheit — a fraction of a degree above absolute zero temperature.

The ultra-cold conditions give the experiment its name: Cryogenic Dark Matter Search, or CDMS. The prefix “Super” indicates an increased sensitivity compared to previous versions of the experiment.

Experiment will measure “fingerprints” left by dark matter
The collisions would also produce pairs of electrons and electron deficiencies that move through the crystals, triggering additional atomic vibrations that amplify the signal from the dark matter collision. The experiment will be able to measure these “fingerprints” left by dark matter with sophisticated superconducting electronics.

Besides Pacific Northwest National Laboratory, two other Department of Energy national labs are involved in the project.

SLAC National Accelerator Laboratory in California is managing the construction project. SLAC will provide the experiment’s centerpiece of initially four detector towers, each containing six crystals in the shape of oversized hockey pucks. SLAC built and tested a detector prototype. The first tower could be sent to SNOLAB by the end of 2018.

Fermi National Accelerator Laboratory is working on the experiment’s intricate shielding and cryogenics infrastructure.

“Our experiment will be the world’s most sensitive for relatively light WIMPs,” said Richard Partridge, head of the SuperCDMS group at the Kavli Institute for Particle Astrophysics and Cosmology, a joint institute of SLAC and Stanford University. “This unparalleled sensitivity will create exciting opportunities to explore new territory in dark matter research.”

Close-knit network of strong partners is crucial to success
Besides SMU, a number of U.S. and Canadian universities also play key roles in the experiment, working on tasks ranging from detector fabrication and testing to data analysis and simulation. The largest international contribution comes from Canada and includes the research infrastructure at SNOLAB.

“We’re fortunate to have a close-knit network of strong collaboration partners, which is crucial for our success,” said Project Director Blas Cabrera from KIPAC. “The same is true for the outstanding support we’re receiving from the funding agencies in the U.S. and Canada.”

Funding is from the DOE Office of Science, $19 million, the National Science Foundation, $12 million, and the Canada Foundation for Innovation, $3 million.

SuperCDMS to search for dark matter in entirely new region
“Together we’re now ready to build an experiment that will search for dark matter particles that interact with normal matter in an entirely new region,” said SuperCDMS spokesperson Dan Bauer, Fermilab.

SuperCDMS SNOLAB will be the latest in a series of increasingly sensitive dark matter experiments. The most recent version, located at the Soudan Mine in Minnesota, completed operations in 2015.

”The project has incorporated lessons learned from previous CDMS experiments to significantly improve the experimental infrastructure and detector designs for the experiment,” said SLAC’s Ken Fouts, project manager for SuperCDMS SNOLAB. “The combination of design improvements, the deep location and the infrastructure support provided by SNOLAB will allow the experiment to reach its full potential in the search for low-mass dark matter.” — SLAC National Laboratory; and Margaret Allen, SMU

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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 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

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Exploring the mysteries of the universe: Reality in the Shadows

New knowledge has caused us to reconsider many previous conclusions about what the universe is and how it works.

Despite centuries of scientific advancements, there is much about the universe that remains unknown. New knowledge and discoveries in the last 20 years have challenged previously accepted ideas and theories that were once regarded as scientific truth and have subjected them to increasing scrutiny.

These additions to our knowledge have caused scientists to reconsider many previous conclusions about what the universe is and how it works.

““Reality in the Shadows”” or “What the Heck’s the Higgs?” is a new book that explores the concepts that shape our current understanding of the universe and the frontiers of our knowledge of the cosmos.

The authors — two physicists and an engineer — tell us in a manner that non-scientists can readily follow, why studies have moved to superstring theory/M-theory, ideas about extra dimensions of space, and ideas about new particles in nature to find answers. It also explores why these ideas are far from established as accurate descriptions of reality.

“Our book explains how we know what we know about the universe, what we don’t know, and what we wish we did know,” said co-author Stephen Sekula, an associate professor of Physics at SMU. A physicist, Sekula conducts research into the Higgs Boson at the energy frontier on CERN’s ATLAS Experiment.

The book was initiated by Frank Blitzer, an engineer who participated on national space programs like Apollo and Patriot, several years ago, Sekula said. He was joined by co-author S. James Gates Jr., well known for his work on supersymmetry, supergravity and superstring theory, a few years ago.

“Frank and Jim sought additional input to help complete the book, and serendipitously Frank’s grandson, Ryan, was an SMU undergraduate and Hunt Scholar who helped connect them to me,” Sekula said. “After over an additional year of work, the book was completed.”

The foundations of modern physics rest on ideas that are over 100 years old and battle-tested, Sekula said.

“But nature has offered us new puzzles that have not yet been successfully explained by those ideas,” he added. “Perhaps we don’t yet have the right idea, or perhaps we haven’t searched deep enough into the cosmos. These are exciting times, with opportunities for a new generation of physicists who might crack these puzzles. Our book will help a curious reader to see the way in which knowledge was established, and encourage them to be engaged in solving the new mysteries.”

“Reality in the Shadows,” available through YBK Publishers, describes how humanity came to learn the workings of the universe as groundwork for the science that found the Higgs particle. Now scientists are hunting for the explanations for dark matter and the accelerated expansion of the cosmos, as well as for the many new questions the Higgs Boson itself has raised.

Scientists have recently discovered colliding black holes and neutron stars, that there is more non-luminous matter (dark matter) in the universe than the ordinary stuff of everyday life, and that the universe seems to grow larger each second at a faster and faster rate. Readers will learn how scientists discern such features of the universe and begin to see how to think beyond what is known to what is not yet known.

Throughout the book are descriptions of important developments in theoretical physics that lead the reader to a step-by-step understanding.

Sekula teaches physics and conducts research at ATLAS. He contributed to the measurement of decay modes of the Higgs boson and to the measurement of its spin-parity quantum numbers. Complementary to these efforts, he has worked with colleagues on the ATLAS Experiment to search for additional Higgs bosons in nature, providing intellectual leadership and direct involvement in several searches.

Gates was named 2014 “Scientist of the Year” by the Harvard Foundation. He was elected to the prestigious National Academy of Sciences in 2013 and received the 2013 National Medal of Science, the highest recognition given to scientists by the United States.

Gates has been featured on many TV documentary programs on physics, including “The Elegant Universe,” “Einstein’s Big Idea,” “Fabric of the Cosmos” and “The Hunt for the Higgs.” His DVD series, “Superstring Theory: The DNA of Reality,” makes the complexities of unification theory comprehensible.

Blitzer has more than 50 years of experience in engineering, program management, and business development and participated on national space programs, and The Strategic Defense Initiative (SDI), holding several patents in guidance and control. He has spent more than 20 years in independent research of the subject of the book.

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The CW33: Dark Matter Day rocks SMU’s campus

The CW33 TV visited SMU on Halloween to get a glimpse of International Dark Matter Day in action on the SMU campus.

The CW33 TV stopped at the SMU campus during the early morning hours of Halloween to interview SMU physics professor Jodi Cooley about the capers afoot in celebration of International Dark Matter Day.

The SMU Department of Physics in Dedman College of Humanities and Sciences hosted the Oct. 31, 2017 Dark Matter Day celebration for students, faculty, staff and Dallas-area residents.

As part of the festivities, there were speaking events by scientists in the field of dark matter, including dark matter expert Cooley, to explain the elusive particles that scientists refer to as dark matter.

Then throughout Halloween day, the public was invited to test their skills at finding dark matter — in this case, a series of 26 rocks bearing educational messages related to dark matter, which the Society of Physics Students had painted and hidden around the campus. Lucky finders traded them for prizes from the Physics Department.

“In the spirit of science being a pursuit open to all, we are excited to welcome all members of the SMU family to become dark matter hunters for a day,” said Cooley, whose research is focused on the scientific challenge of detecting dark matter. “Explore your campus in the search for dark matter rocks, just as physicists are exploring the cosmos in the hunt for the nature of dark matter itself.”

Watch the full news segment.

EXCERPT:

By Shardae Neal
The CW33
On Halloween (excuse us) “International Dark Matter Day,” SMU students hosted a public witch hunt to search for the unknown: dark matter.

“What we’re doing is hiding 26 rocks that we have with the help of our society of physic students,” explained SMU Physicist Jodi Cooley.

What exactly is dark matter?

“Think about all the stuff there is in the universe,” Cooley added. “What we can account for makes up only four to five percent of the universe. The rest of it is unknown. Turns out 26% of that unknown stuff is dark matter.”

Watch the full news segment.