By Ashley Yeager
This artist’s impression shows a proton-proton collision producing a pair of gamma rays, in yellow, in the ATLAS detector at LHC. Credit: CERN.
Scientists say the particle they described in July 2012 is looking more like a Higgs boson. But they can’t yet say much more than that.
Speaking at the Moriond meeting in Italy, researchers using the Large Hadron Collider near Geneva explained their latest analyses show the new particle’s “spin” matches theorists’ predictions for that feature of the Higgs boson.
Physicists want to find a Higgs boson because it would give them clues to the mechanism that gives mass to elementary particles. Finding one specific flavor of the particle would also complete the Standard Model of particle physics, a system that explains how the smallest particles and forces interact to run the universe.
“The updates show this particle is Standard Model-like, but my personal feeling is we can’t yet call it ‘the’ Standard-Model Higgs,” says Duke physicist Mark Kruse who works on one of the Higgs-hunting experiments at CERN. “For one, we believe the Standard Model is wrong.”
The model, he says, does not predict a candidate for dark matter, a form of mass that scientists can’t yet describe. And, he adds, even if the particle’s characteristics, such as spin, match those of the Standard-Model Higgs, scientists can’t yet rule out other theories that also contain Higgs particles with properties similar to the Standard-Model Higgs.
“All we can really say is that this particle is ‘a’ Higgs boson, but not necessarily ‘the’ Standard-Model Higgs,” Kruse says. “We have a lot more to understand and a lot of future research to acquire that understanding.”