Evidence Grows for Higgs Boson Discovery

The particle discovered last summer during experiments at the Large Hadron Collider (LHC) is looking more than ever like a Higgs boson, according to preliminary results released at the Moriond Conference this week in La Thuile, Italy.

After analyzing data from 2000 trillion collisions of subatomic particles — more than twice as much as the data that led to the original discovery last year — physicists working on the CMS (compact muon solenoid) and ATLAS (A Toroidal LHC ApparatuS) experiments say they are confident that the particle they discovered is the Standard Model Higgs. The Standard Model of physics describes the fundamental particles from which we, and every visible thing in the universe, are made, and the forces acting between them. (See: Search for Higgs Boson at LHC Reveals New Particle)

“The preliminary results with the full 2012 data set are magnificent,” said Joe Incandela, a professor at the University of California, Santa Barbara, and a spokesman for the CMS experiment at CERN (European Organization for Nuclear Research). “To me, it is clear that we are dealing with a Higgs boson, though we still have a long way to go to know what kind of Higgs boson it is.”

Remote Operations Center at Fermilab. Courtesy of BNL.

“Clear evidence that the new particle is the Standard Model Higgs boson still would not complete our understanding of the universe,” said Patty McBride, head of the CMS Center at Fermi National Accelerator Laboratory (Fermilab) in Batavia, Ill. “We still wouldn’t understand why gravity is so weak, and we would have the mysteries of dark matter to confront. But it is satisfying to come a step closer to validating a 48-year-old theory.”

Scientists have specific predictions for how often a Standard Model Higgs boson of a certain mass will decay into different patterns of particles. The detection of the boson is a very rare event — it takes about 1 trillion proton-proton collisions for each observed event. To characterize all of the decay modes will require much more data from the LHC; however, the latest results indicate that the particle is sticking to the Standard Model’s script.

“When we discovered the particle, we knew we found something significant,” ATLAS scientist and New York University professor Kyle Cranmer said. “Now we’re just trying to establish the properties.”

CERN’s collider is down for two years of maintenance and upgrades, but researchers will continue to study the data collected before the shutdown to determine whether the particle is a Standard Model Higgs boson or something more surprising.

More than 1700 scientists and graduate students from US institutions — including 89 American universities and seven Department of Energy (DoE) national laboratories — helped design, build and operate the LHC accelerator and its four particle detectors. The US, through the DoE’s Office of Science and the National Science Foundation, provides support for research and detector operations at the LHC and also supplies computing for the ATLAS and CMS experiments. Fermi National Accelerator Laboratory and Brookhaven National Laboratory host the US contingents of the CMS and ATLAS experiments, respectively.

For more information, visit: www.cern.ch