Higgs Progress

The Large Hadron Collider has been humming along this year, collecting about 5 inverse femtobarns of data, similar to what they had all last year, at a slightly higher energy (8 TeV vs. 7 TeV). Of course last year we were treated to tantalizing hints of a Higgs boson with a mass of about 125 GeV, so it’s natural to ask whether that evidence has been continuing to accumulate. Answers should be forthcoming early in July at the International Conference on High Energy Physics in Melbourne, where talks are scheduled from both CMS and ATLAS.

I believe, given the short time available, that each collaboration can update us on the results from this year’s run thus far, but it will probably take longer to combine the results from the two experiments, as well as combining with last year’s data. (Combining results sounds straightforward, but is actually extremely subtle, due to separate kinds of systematic effects for the different experiments, or even the same experiment at different energies.) Presumably that means that we can accumulate new evidence for the Higgs, but it would be surprising if they were actually able to announce a discovery. I’m also told that the analysis of this year’s data thus far has been “blind” — i.e., they add a secret offset to the real data so that all of the reduction and background subtraction can be carried out without bias, and only then do they “open the box” and see what the actual data are saying. If this is true, literally nobody in the world knows right now what the LHC has actually been seeing, as far as the Higgs is concerned. But we’ll find out before too long.