A 2011 proton collision from the Large Hadron Collider, consistent with… (CERN )
It seems increasingly likely that the subatomic particle ferreted out by physicists at the Large Hadron Collider near Geneva last year is indeed a Higgs boson, scientists said Wednesday after a day of talks at a physics conference in Italy.
First theorized by scientists in the 1960s, the idea of the Higgs boson grew out of musings over the question: why does matter exist?
As I wrote in this July 2012 Los Angeles Times story about the LHC discovery, one possibility presented by the University of Edinburgh's Peter Higgs and others was that particles gain mass by traveling through an energy field which field sticks to the particles, slowing them down and imparting mass. That energy field came to be known as the Higgs field; the particle associated with it, the Higgs boson.
It took more than 40 years to get a collider powerful enough to create and detect a candidate Higgs boson, but once the particle was identified at the LHC, scientists began working on amassing more evidence to confirm that they had, indeed, found what they thought they had found.
This week some said that getting more confirmation that theorists had been right about the Higgs was vexing, as well as gratifying.
“What most of us are motivated by is to find out something new, not just to measure some number to more accurate precision,” said UCLA physicist Robert Cousins, a member of one of the LHC teams that detected the elusive particle, adding that “up till now, there’s no new stuff that’s obvious.”
On Wednesday, physicists at the Moriond conference attended talks detailing some of the latest observations by teams at the European Organization for Nuclear Research, also known as CERN, which operates the LHC. Scientists from Fermilab’s now-shuttered Tevatron collider, near Chicago, also presented Higgs results.
In general, the findings were consistent with the Higgs boson long predicted by the Standard Model of particle physics, which describes the subatomic particles that make up the universe and how they interact. Scientists aren’t ready to confirm that the newly-detected particle is definitively the Higgs predicted by the model--they still need more data. But so far, Cousins said, experiments seem to indicate that they have a good match.
“On the whole,” he said, “people are thrilled with the way the accelerator worked. After 20 years building the thing, now we’re drowning in data. That’s what we get excited about.”
But the frustration with the results so far, for many physicists, is that the Standard Model doesn’t explain everything they’d like to know about our universe. It doesn’t account for the existence of dark matter, for example. So while it’s nice to see that the decades-old predictions about the Standard Model Higgs have held up so beautifully, many physicists had hoped that more unexpected findings would also emerge from the LHC runs — discoveries that might point the way toward “new physics” that might offer insights into some of the unanswered questions.
Many, for instance, are fond of a theory known as supersymmetry, which attempts to describe a more unified explanation of how things work, and suggests that there must be more subatomic particles awaiting discovery. But the first two years of LHC data haven’t yet unearthed hoped-for signals of supersymmetric particles.
Physicists will continue sifting through the 2011 and 2012 data, to understand the characteristics of the new Higgs-like particle with more and more precision and to look for hints of the unexpected, Cousins said. The LHC will start churning out data anew when it resumes proton-proton collisions in 2015.
For more background, see this Los Angeles Times piece from 2012 about the ongoing search for the Higgs, this 2011 Q & A with UCLA’s Cousins and this Q & A with Fermilab’s Giovanni Punzi.