CMS collaboration celebrates the success of 2011

Lothar Bauerdick, head of the CMS Center, wrote this week’s column.

Lothar Bauerdick

In all respects, 2011 was a hugely successful year for the LHC and the CMS experiment. Since January, the CMS collaboration has submitted 70 publications to the arXiv server. Over the course of the year, the experiment harvested 5.2 inverse femtobarns of collision data–five times the data to analyze compared with what was predicted a year ago. The CMS detector accumulated proton-proton collision data with a very high 91 percent efficiency. The quality of the data is very good, with an average fraction of operational channels per subsystem that is approaching 99 percent.

The first scientific results using the full data set of 2011 are now coming out. One of the most anticipated results using this vast new data set is, of course, the Higgs search. Our latest results were presented to the CERN Council and made public yesterday morning. These are beautiful achievements, and the experiments are closing in on the Higgs. To conclusively find or exclude the Higgs, the experiments will need another year of running.

Going into next year, we expect another large increase in the LHC data sample. Getting 15 inverse femtobarns in 2012 seems feasible. That would be enough to discover the Standard Model Higgs boson or to rule out its existence. The CMS collaboration would like the LHC accelerator to run at the increased beam energy of 8-TeV collision energy, and go from 50-nanosecond bunch spacing to 25 nanoseconds, thereby increasing the number of proton bunches in the accelerator. The 14 percent increase in energy would bring significant additional discovery reach. Running at 25-nanosecond bunch spacing would bring down the number of background interactions during each bunch crossing, which would help all LHC experiments to trigger interesting events more reliably. Both changes are feasible, and the exact running conditions will be decided at a meeting in Chamonix in a few months. Until then, there are more CMS results coming out every week!