Hunt for the Higgs boson: A quick update

And it was good news after all! In an announcement made earlier today at the special conference called by CERN near Geneva, the discovery of a Higgs-boson-like particle was announced by physicists from the ATLAS and CMS collaborations that spearheaded the hunt. I say discovery because the ATLAS team spotted an excess of events near the 125-GeV mark with a statistical significance of 5 sigma. This puts the chances of the observation being a random fluctuation at 1 in 3.5 million, a precision that asserts (almost) certainty.

Fabiola Gianotti announced the preliminary results of the ATLAS detector, as she did in December, while Joe Incandela was her CMS counterpart. The CMS results showed an excess of events around 125 GeV (give or take 0.6 GeV) at 4.9 sigma. While the chances of error in this case are 1 in 2 million, it can’t be claimed a discovery. Even so, physicists from both detectors will be presenting their efforts in the hunt as papers in the coming weeks. I’ll keep an eye out for their appearance on arXiv, and will post links to them.

After the beam energy in the Large Hadron Collider (LHC) was increased from 3.5 TeV/beam to 4 TeV/beam in March, only so many collisions could be conducted until July. As a result, the sample set available for detailed analysis was lower than could be considered sufficient. This is the reason some stress is placed on saying “boson-like” instead of attributing the observations to the boson itself. Before the end of the year, when the LHC will shut down for routine maintenance, however, scientists expect a definite word on the particle being the Higgs boson itself.

(While we’re on the subject: too many crass comments have been posted on the web claiming a religious element in the naming of the particle as the “God particle”. To those for whom this monicker makes sense: know that it doesn’t. When it was first suggested by a physicist, it stood as the “goddamn particle”, which a sensitive publisher corrected to the “God particle”).

The mass of the boson-like particle seems to deviate slightly from Standard Model (SM) predictions. This does not mean that SM stands invalidated. In point of fact, SM still holds strong because it has been incredibly successful in being able to predict the existence and properties of a host of other particles. One deviation cannot and will not bring it down. At the same time, it’s far from complete, too. What the spotting of a Higgs-boson-like particle in said energy window has done is assure physicists and others worldwide that the predicted mechanism of mass-generation is valid and within the SM ambit.

Last: the CERN announcement was fixed for today not without another reason. The International Conference on High Energy Physics (ICHEP) is scheduled to commence tomorrow in Melbourne. One can definitely expect discussions on the subject of the Higgs mechanism to be held there. Further, other topics also await to be dissected and their futures laid out – in terms vague or concrete. So, the excitement in the scientific community is set to continue until July 11, when ICHEP is scheduled to close.

Be sure to stay updated. These are exciting times!