|UT Arlington physicists celebrated with scientists worldwide on December 13 with the announcement by researchers at the Large Hadron Collider at CERN near Geneva, Switzerland that they have found the first "tantalizing hints" of the elusive Higgs boson particle in a narrow region of mass ranges, news celebrated throughout the world's scientific community.
The College of Science's High Energy Physics team is part of the U.S. team contributing to the experiments, both on-site in Switzerland and by analyzing data at the University's massive data center. UT Arlington researchers held a seminar on December 13 in the Chemistry Physics Building to discuss the work. They are part of the ATLAS experiment, one of two research groups that revealed the intriguing results.
Physicists believe interaction with the Higgs boson gives particles in the universe their mass. It is the only particle in the physics Standard Model that has not been observed. Physicists at the $10 billion Large Hadron Collider have been aggressively seeking it.
The news means the Higgs hunters are coming very close to filling in this missing piece, said Kaushik De, physics professor and co-director of the High Energy Physics Group.
"After 15 years of contributions to ATLAS by our group here at The University of Texas at Arlington, it is exciting to be at the threshold of an astonishing scientific breakthrough," he said. "We have reached an important milestone in the long search for the elusive Higgs particle. We have ruled out large regions where the Higgs cannot exist. More interestingly, we have found a narrow region with the first hint of its existence. Only more data, expected in 2012, can tell if this is really the Higgs or an accidental fluctuation in the data."
In a news release from CERN, Fabiola Gianotti, ATLAS experiment spokesperson, agreed.
"We have restricted the most likely mass region for the Higgs boson to 116-130 GeV, and over the last few weeks we have started to see an intriguing excess of events in the mass range around 125 GeV. This excess may be due to a fluctuation, but it could also be something more interesting," she said. "We cannot conclude anything at this stage. We need more study and more data. Given the outstanding performance of the LHC this year, we will not need to wait long for enough data and can look forward to resolving this puzzle in 2012."
Mass ranges are defined in GeV or gigaelectronvolt, a unit of energy equal to one billion electron volts.
Though its discovery will be a watershed event, scientists at UT Arlington and in Switzerland reiterated that locating the Higgs, or ruling it out, starts a host of new questions and potential experiments.
"The prospect of confirming the discovery of the Higgs in 2012 is extremely exciting as it opens the possibility for finding many other new physics phenomena that have been long predicted," said Andrew White, physics professor and co-director of the High Energy Physics Group. "If the Higgs is confirmed in 2012, this will set the stage for the next major High Energy Physics facility - the International Linear Collider. The LHC and the ILC working together can reveal the details of mechanisms and symmetries of nature at the most fundamental level."
Jae Yu, associate professor of physics, said, "The Higgs particle is a manifestation of the mechanism that gives mass to particles in the universe. Physicists have been searching for this elusive particle for over four decades. It is exciting that we finally have a hint of the existence of the Higgs particle. A definitive discovery of the Higgs particle, however,
is only the beginning. It will raise a whole new set of questions that need the next generation accelerator to measure the properties of the discovered particle more precisely and determine whether this is the Higgs particle in the Standard Model or a new type of particle that requires a whole new theory."
|A proton-proton collision at the Large Hadron Collider. Courtesy of ATLAS Collaboration
Andrew Brandt, professor of physics, addressed how to upgrade ATLAS for better measurement of the Higgs.
"When it looks like a duck, you really want to hear it quack too, just to be sure," Brandt said. "We've seen something that looks like a Higgs, but good science demands that one not jump to conclusions, but examine all the details. It's interesting to note that only one out of every 500 or so Higgs boson decays into two photons, but this channel has relatively low background rates, so the thousands of other Higgs that have presumably been created during this past year managed to escape unnoticed, because they blended in better."
"The proposed ATLAS proton detector that I've been developing for the last several years was conceived to help figure out what type of Higgs this might be, if it is a Higgs. So the timing of this indication of a light Higgs couldn't be better, as it greatly strengthens the potential physics case for proposals to NSF and DOE to fund this new detector. UTA undergraduates have had a big role in this research, and would continue to be a critical part through the completion of the research and development phase, prototyping, testing, and commissioning phase. "
Amir Farbin, assistant professor of physics, said observing a light Higgs would mean something new and more exciting is within reach of the LHC.
"The Standard Model tells us the Higgs is light, but doesn't explain why it is light," Farbin said. "Most likely, some yet unseen particles are responsible. What's more, they are probably within the reach of the LHC. Only acceptably natural ways to keep the Higgs mass down seem to have interesting ramifications, like supersymmetry or extra-dimensions. A measurement of the Higgs mass provides an arrow in our extrapolation up to where completely new phenomena will exhibit themselves.
"If we are lucky, we'll reach an observation with more data. Then we'll have to study the Higgs. Check his ID and see if he is the Standard Model Higgs. Higgs or not, this is an impressive achievement for our colleagues."
Added Chris Jackson, assistant professor of physics, "For a theorist, this is very exciting news because it means we are on the verge of answering one of the fundamental questions in particle physics: 'What is the origin of mass?' The fact that the signal lies in a region agreeable with a supersymmetric Higgs boson also implies that there may be many more exciting discoveries to come."
To learn more about the announcement from CERN, visit http://public.web.cern.ch/public/ or http://fnal.gov/pub/presspass/press_releases/2011/uslhc_20111213.html.
Posted January 25, 2012