Discovery Magazine

Photo Credit: CERN/CMS

Experimental Investigation of Hadron Collisions at the Highest Center-of Mass Energies

This proposal describes our program of original research in the physics of elementary particles and fields studied in proton-proton collisions at multi-TeV center-of-mass energy at the Large Hadron Collider (LHC) particle accelerator located at the European Center for Particle Physics, CERN, in Geneva, Switzerland. Since 2010, the LHC has delivered record luminosities and large data sets from the collisions at 7 and 8 TeV, which have been recorded using the Compact Muon Solenoid (CMS) experiment, which comprises a large system of state-of-the-art particle detectors allowing precision measurement of final state leptons, missing energy and jets.

A review of our recent accomplishments is presented describing our responsibilities and work performed for CMS detector performance and calibration, as well as software and physics analyses – performed on the Florida Tech campus and at CERN. Our hardware-related efforts were: 1) final commissioning and successful operation of the forward hadron calorimeters (HF); 2) calibration and performance studies of the hadron calorimeters (HCAL) using collision data, identification of noise sources and tuning of timing for optimal noise rejection leading to improved missing ET measurement critical to many physics studies; 3) investigation and correction of HF ‘ageing’ caused by a high load of phototubes during the high luminosity runs and radiation damage attributed to the darkening of the fibers embedded in the absorbers.

On the physics analysis side, with our graduate students we have been actively engaged in a number of physics analyses: studies of top quark production and its spin, b quark production and search for heavy W′, which led to five Ph.D. dissertations, completed in 2009-11, and several major CMS journal publications and internal CMS analysis notes in top and bottom quarks physics.

Next, we describe our plans for ongoing efforts and obligations, as well as new tasks in CMS for the next three years, FY13-15. For hardware-related efforts, we have obligations in HF maintenance and operation until the end of the present run, early 2013. We have also identified two CMS upgrade projects, in which the group could make significant contributions given our expertise and past CMS activities. The first project concerns the HCAL light (laser and LED) calibration systems, which require a series of upgrades over the first two periods of the LHC long shutdowns (2013-14 and 2018). The second project is on modifications of the jet particle flow reconstruction tools for the upgraded HCAL detector and optimization of these algorithms for high luminosity scenarios. Florida Tech is in the position of leading these upgrade efforts.

As for physics, we currently supervise three graduate students pursuing CMS physics analyses with one more joining the group starting spring 2013. The group continues with top quark physics, particularly measurement of top quark properties, but also plans to conduct searches for phenomena beyond the Standard Model, e.g., events with four top quarks in final state. Clearly with abudant data, physics productivity will be a priority in the next 2 years, during when we intend to complete our analyses with journal publications. With Yumiceva, who has extensive expertise in top and bottom quarks physics, we have formed a Florida Tech top quark physics group with current focus on measurement of top antitop quarks spin correlation and search for new physics using top quarks. This, along with participation in upgrade, will strengthen our footprint in CMS and increase our productivity, making Florida Tech a more prominent member of CMS.