SMU scientists celebrate Nobel Prize for Higgs discovery

Robert Kehoe

SMU scientists celebrate Nobel Prize for Higgs discovery

Particle collision from the ATLAS ExperimentSMU’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.”

“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.

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.

• 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, Daniel Goldin and Sami Kama.

• SMU has awarded eight Ph.D. and seven M.S. 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.”

> Read the full story from SMU News

October 8, 2013|News, Research|

Three receive 2013 Distinguished University Citizen Awards

Three faculty members were honored with SMU’s 2013 Distinguished University Citizen Award at the Faculty Breakfast held Saturday, May 18 before Commencement. This year’s recipients are:

  • Robert Kehoe, Physics, Dedman College of Humanities and Sciences
  • Dennis Simon, Political Science, Dedman College of Humanities and Sciences
  • Paige Ware, Teaching and Learning, Annette Caldwell Simmons School of Education and Human Development

The award winners became part of “a strong list of distinguished faculty who have served SMU extraordinarily well and whose examples continue to energize SMU and encourage each of us,” said Associate Provost Harold Stanley in presenting the honors.

The award, given by the Provost’s Office, honors three faculty members each year for service and activities that benefit students and the University’s academic mission.

May 21, 2013|For the Record, News|

Research: SMU students discover two new supernovae

SMU graduate student researchers have discovered two new supernovae, and their observations of these massive exploding stars will help improve the astronomical “tape measure” that scientists use to calculate the acceleration of the expansion of the universe.

A supernova discovered Wednesday, Feb. 6, 2013 exploded about 450 million years ago, said Farley Ferrante, a graduate student in the Department of Physics 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 Tuesday, Nov. 20, 2012 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 supernovae, 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. 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 astronomy team in the 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. Its 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.

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.”

Written by Margaret Allen

> Read more from the SMU Research blog

March 5, 2013|Research|

Bob Kehoe named SMU Director of Undergraduate Research

Robert KehoeAssociate Professor Robert Kehoe, coordinator of SMU’s Undergraduate Research Assistantships program and director of undergraduate research in the Department of Physics, has been named the University’s new Director of Undergraduate Research. He reports to James Quick, Associate Vice President for Research.

Kehoe sums up undergraduate research as “one of the single most promising recent developments to enhance student learning and prepare them for their ultimate career or vocation.

“It propels students out of the classroom to confront new questions and opportunities armed with the knowledge they have newly gained,” he says. “It does this while students are still supported by the SMU community. Undergraduate research provides a valuable intermediate space between classroom curriculum and professional possibilities.”

An SMU professor since 2004, Kehoe received his B.A. degree in physics from Earlham College and his Ph.D. degree in high-energy physics from the University of Notre Dame. He completed postdoctoral study in astrophysics and high-energy physics at the University of Michigan and Michigan State University, respectively.

Kehoe is a member of the SMU team on the ATLAS Experiment, the largest detector in the Large Hadron Collider array at the European Organization for Nuclear Research (CERN) in Geneva, Switzerland. His longstanding research into subatomic particle mass played a role in the search for the long-sought Higgs boson. He also contributed directly to the analysis published in summer 2012 that observed a new particle consistent with the Higgs.

His Higgs research focused on controlling and quantifying the large amount of background created in the production of two very massive charged particles used to help detect the previously unknown Higgs boson, as well as on understanding the large theoretical uncertainties involved in the production of those particles.

As a collaborator in Fermilab’s DZero experiment, Kehoe led analysis of data from particle collisions resulting in two leptons, which helped improve measurements of the mass of another heavy subatomic particle called the top quark. Physicists theorize that this particle — because of its sizable mass — is sensitive to the Higgs and therefore may point to it, and that knowing the mass of the top quark narrowed the range of where the Higgs can be expected.

“Professor Kehoe knows good research and good research opportunities when he sees them,” Quick remarked during the announcement of Kehoe’s new duties at the University’s 2012 Engaged Learning Expo on Aug. 27. Kehoe will continue to teach and do research in the Department of Physics.

Kehoe says his new position gives him “a well-defined role and a well-defined way to communicate with people. Now we can have a discussion about undergraduate research that will involve all of SMU.” His primary goal will be to expand and help enrich research opportunities and experiences for SMU undergraduates, he says.

Cooperation among programs and consistent communications to students and parents “are hard to do by individual project coordinators in a way that benefits everyone,” Kehoe adds. An office dedicated to building those connections “opens a whole new avenue for collaboration.”

In addition, Kehoe will help to implement assessment for program effectiveness, as well as integration with the research component of SMU’s Engaged Learning initiative.

Kehoe has already started informal discussions with faculty and will consult with the coordinators of undergraduate research programs across campus. His main focus will be to help existing programs and help develop new ones, he says.

“We’ll take a look at the programs we already have so we can discuss what’s missing,” as well as learning about faculty ideas for new programs, he says. He intends to establish a group to create a strategic plan for undergraduate research “with the input of a broad cross-section of SMU,” including faculty, students and program coordinators.

“My job is not to tell program coordinators what to do,” he says. “My job is to help them produce and coordinate common resources and practices, as well as to disseminate information that will enhance recruitment and retention.”

To this end, Kehoe will direct an expansion of SMU’s online undergraduate research presence, including a new website and the production of an online undergraduate research journal. He will also help create marketing campaigns and other communications for current and prospective students and faculty members.

October 9, 2012|News, Research|

Research Spotlight: CERN scientists close in on Higgs boson

An event showing four muons (red tracks) from a proton-proton collision in ATLAS. This event is consistent with two Z particles decaying into two muons each. Such events are produced by Standard Model processes without Higgs particles. They are also a possible signature for Higgs particle production, but many events must be analyzed together in order to tell if there is a Higgs signal. (Image courtesy of CERN.)

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.

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.

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

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.”

Besides Stroynowski, the SMU team of researchers includes three other Physics Department faculty: Jingbo YeRobert 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.

“SMU’s role in the LHC experiments provides our students a chance to participate in pioneering discoveries,” Olness said. “SMU students helped build the ATLAS detector, they were in the control room when the experiment started up, and they contributed to the analysis. 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.”

SMU's Ryszard Stroynowski and Ryan Rios

In Fondren Science Building, physicist and SMU Physics Professor Ryszard Stroynowski and physics graduate student Ryan Rios discuss the Higgs boson after viewing a CERN web cast Tuesday announcing evidence of the Higgs. (Photo by Hillsman S. Jackson.)

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 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.’”

– Written by Margaret Allen

> Read the full story at the SMU Research blog

December 14, 2011|News|
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