It was announced today at CERN as a ‘curtain raiser’ for the International Conference of High Energy Physics – ICHEP2012 – currently on in Melbourne, Australia. And what a curtain raiser it is.
The Higgs boson is a subatomic particle that, theoretically, gives mass to everything. It interacts with the Higgs field which permeates the Universe, kicking up a drag as it moves. That drag, or attraction, gives protons and electrons their mass as they zoom through the Higgs field. In the model, the Higgs boson is absent in photons of light, which is why they have no mass.
It’s been a long, hard road to find it – taking 45 years. Why? Partly because, after the collisions, they decay very fast, and partly because the way in which they decay doesn’t stand out. It seems to vanish into very normal smoke, that is, quarks, antiquarks and muons the same as those made by run-of-the-mill activity from other LHC collisions. It’s like trying to spot stars in daylight, according to this neat article by Matt Strassler.
The physicists are being cautious with their discovery, describing it as a Higgs-like particle. There’s more data analysis and experiments to be done. But if it looks and smells like a Higgs boson…
What it looks and smells like, to be precise, is a ‘bump’ in the data with a mass of 125.3 gigaelectronvolts, about as heavy as 125 protons.
Analysing the data, so far, has put it at a confidence level of 5 sigma. That means there’s less than a one-in-three million chance of receiving the same result completely by chance, without a Higgs boson. Put another way, that means they can feel over 99.999 percent sure this is it – a boson that acts like a Higgs.
“The results are preliminary but the 5 sigma signal at around 125 GeV we’re seeing is dramatic. This is indeed a new particle. We know it must be a boson and it’s the heaviest boson ever found,” said CMS experiment spokesperson Joe Incandela in the press release. “The implications are very significant and it is precisely for this reason that we must be extremely diligent in all of our studies and cross-checks.”
“It’s hard not to get excited by these results,” said CERN Research Director Sergio Bertolucci in the same release.
It is exciting! Even though it’s still a preliminary result – guys, it could be the God particle! How cool is that?