There’s some excitement in the physics world today as CERN has made a tentative announcement about possible evidence for the Higgs boson. The Higgs is an elementary particle that was first proposed in the 1960s by a theorist, Peter Higgs, as a way of solving some problems in elementary particle theory. It was later incorporated, for the same reasons, into the Standard Model of particle physics, where it has remained ever since, although there has not been any direct evidence for its existence.
The announcement from CERN is that two of the experiments there, doing independent analyses, see possible evidence for the Higgs at a mass of about 125 GeV. (For comparison, the proton has a mass of about 1 GeV. The heaviest known elementary particle, the top quark, has a mass of about 172 GeV.) The statistical significance of the data, however, is not high enough to claim a discovery. It could just be a statistical fluctuation that will go away as more data are collected.
A friend who is privy to these things tells me that rumours have been swirling at CERN this fall that the Higgs was not showing up in the data. It is possible that today’s announcement is political, seizing on some tantalizing, but low significance, data in order to placate critics. Time will tell.
A generally good article from BBC News states:
Finding the Higgs would be one of the biggest scientific advances of the last 60 years.
I would argue it the other way: not finding the Higgs would be bigger news, because it would mean that the Standard Model is wrong. Finding just the Higgs predicted by the Standard Model, on the other hand, would be rather disappointing. For decades, most physicists have assumed that it, or something like it, must exist.
If CERN is indeed seeing the Higgs, then the mass estimate of about 125 GeV is potentially quite interesting. The Higgs mass is sensitive to quantum fluctuations which tend to lift it to higher — much higher — values. The most popular extension of the Standard Model, called supersymmetry, has the nice property of stabilizing the Higgs mass. However, a light Higgs such as the one hinted at in these data today actually does not need stabilization as much as a heavier Higgs would. These data, therefore, lessen the need for something like supersymmetry. A Higgs discovery, if it resulted in strong constraints on supersymmetric theories, would be a praiseworthy public service.
Incidentally, I notice that many news articles on this story are referring to the Higgs boson as “the god particle”. This name comes from a book by Leon Lederman, who actually wanted to call it “the goddamn particle”, but was prevented by his publishers. The name may be safely ignored.