Today finds me in Canada, at the Perimeter Institute in Waterloo, Ontario, where I’ll be for the next few days. I’m attending a workshop on strategies for searching for new phenomena at the Large Hadron Collider (LHC), which is bringing together a couple of dozen theorists like myself with experimentalists in leadership positions at the CMS experiment, one of the experiments at the LHC. More on that later, though I won’t be at liberty to discuss details.
Meanwhile, yesterday ATLAS and CMS, the two general purpose experiments at the LHC, released their pre-publication papers that summarize their observation of a new Higgs-like particle. (Here’s ATLAS’s and here’s CMS’s paper; they’ve been submitted now to the journal Physics Letters, which normally doesn’t publish tomes.) These documents give a more final form to the preliminary results that were presented by the two experiments July 4th, along with the additional preliminary result presented by ATLAS on July 18th (which I described briefly here). Revisions before publication are still possible though less likely.
Aside from the fact that there are lots of little changes in the results (as is to be expected when preliminary results become final) and a few new plots that are interesting to look at, the main new result is that ATLAS now presents a mass measurement, of 126.0 +/- 0.4 +/- 0.4 GeV/c2, for the new particle, completely consistent with CMS’s result that gives 125.3 +/- 0.4 +/- 0.5 GeV/c2. No real surprises here that I’ve noticed as yet.