Actively Working to Collect and Analyze Data at the LHC

This fall, it has been a busy time collecting and analyzing data coming from the Compact Muon Solenoid (CMS) detector located at the Large Hadron Collider near Geneva, Switzerland. This last summer, the accelerator started up again colliding protons at an energy of 13.5 trillion electron volts compared to the 8 trillion electron volts it was colliding at prior to a shutdown in 2013. For the CMS collaboration, we worked hard over the almost 2 year shutdown to make sure that our detector was ready to take data at the higher energy. There was a huge effort from the accelerator group at CERN to commission the beams at the higher energy and deliver data.

Similarly, there was quite an effort by our collaboration of over 3000 physicists, technicians, and engineers from over 40 countries to keep our detector collecting the data at optimal levels. A central part of our detector is a very large size magnet that produces a magnetic field near 4 Tesla that operates at very cold temperatures. Keeping the cryogenics system free of contaminants so that the superconducting magnet could work was a big achievement. The accelerator collided protons for data taking through mid-November and we were able to collect a good data sample to analyze. Then the accelerator produced lead ion collisions for a few weeks for the heavy ion physicists to study dense nuclear states similar to those thought to be present near the beginning of the universe. The accelerator is now shut down for the normal end of the year technical stop. Both the accelerator folks and our CMS collaboration will perform service work including cleaning out contaminant from the cold-box for our CMS magnet. The accelerator will then turn on again sometime in March to start colliding protons again so that we can collect a much bigger data sample.

Our collaboration has been intensely studying this first higher energy proton collision data that we collected. We are searching far and wide for different signs of new physics beyond what we know from the Standard Model of particle physics. We also continue to study the so-called Higgs boson which we discovered in 2012. Our Univ. of Kansas team is looking for a heavy particle that decays into the Higgs boson and a top quark for instance. Like many other analyses in our collaboration, we have more analysis work ahead before we are ready to present results.

However, at CERN on Dec 15, the first official results were presented by both our CMS collaboration team as well as the ATLAS collaboration teams. For CMS, presently, there are more than 33 new results that are public. There is great excitement over any results that show even marginal statistical significance including one signal that was presented looking at the decay to two photons. As expected the theorists are all on a feeding frenzy trying to figure out what they think is causing the potential signal. We will have to wait and collect more data to see whether this is just a statistical fluke or a real indication of new physics. I know with the holidays approaching it is hard to be patient, but even I am hopeful that something is there to find in the new year whether the data is already collected or it will be next year.