Last July, physicists at CERN confirmed the discovery of the Higgs boson, the last missing piece of the Standard Model of particle physics. Well, I thought they had confirmed it, but according to news sources today it’s been really, really confirmed. That puzzled me, but apparently at a meeting the new particle has been announced to have a spin of zero, as required for the Higgs (it’s the only particle with zero spin). The BBC reports:
“This is the start of a new story of physics,” said Tony Weidberg, Oxford University physicist and a collaborator on the Atlas experiment.
“Physics has changed since July the 4th – the vague question we had before was to see if there was anything there,” he told BBC News.
“Now we’ve got more precise questions: is this particle a Higgs boson, and if so, is it one compatible with the Standard Model?”
The results reported at the conference – based on the entire data sets from 2011 and 2012 – much more strongly suggest that the new particle’s “spin” is zero – consistent with any of the theoretical varieties of Higgs.
“The preliminary results with the full 2012 data set are magnificent and 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,” said CMS spokesperson Joe Incandela.
As is often the case in particle physics, a fuller analysis of data will be required to establish beyond doubt that the particle is a Higgs of any kind. But Dr Weidberg said that even these early hints were compelling.
“This is very exciting because if the spin-zero determination is confirmed, it would be the first elementary particle to have zero spin,” he said.
I’ve recommended before that you read Sean Carroll’s new book to learn about the hunt for the Higgs, and recently the New York Times also published a long and informative piece by Dennis Overbye called “Chasing the Higgs”. Note that, unlike other multipage NYT pieces, you must click on the arrow at the bottom right of each page to go from one section to the next.