Experimental Elementary Particle Physics

Cornell’s particle physicists are doing experiments at both the Large Hadron Collider (LHC) at CERN and the Cornell Electron Storage Ring (CESR) located on the Cornell campus. The LHC, slated for first collisions in 2007, will be the first collider to explore the TeV energy scale, where the Standard Model of particle physics will break down unless new phenomena appear. Research topics include mechanisms for electroweak symmetry breaking, including the Higgs mechanism and alternatives, scenarios for physics beyond the Standard Model such as supersymmetry, extra dimensions and new strong interactions, top quark physics, and dark matter. Cornell is a member of CMS, one of two detectors for particle physics at the LHC. (CMS stands for the Compact Muon Solenoid detector – but it’s compact only if you think a six-storey detector is small.) Cornellians are designing online software for the pixel detector, developing strategies for identifying electrons in the electromagnetic calorimeter, writing analysis software capable of handling petabytes of data distributed world-wide, and ensuring that the exciting phenomena initiate readout of, or trigger, the detector. In the next few years, they will also start developing hardware upgrades of the pixels and the trigger.

The Cornell high-energy group is also a major participant in the CLEO collaboration, a 120-person operation that utilizes the state-of-the-art CLEO detector at the CESR storage ring. Through early 2008, CESR will produce a copious and crystal clean sample of charm quarks that will answer important questions about weak and strong interactions and will test promising new lattice QCD calculations. CLEO physicists are studying recently discovered bound states in hopes of discovering their components, are exploring quark mixing, and are making measurements that may help reveal beyond-the-Standard-Model physics before the LHC turns on. For students, CLEO offers the rare opportunity to be involved in all aspects of operating the detector and analyzing the data. They are thoroughly integrated into the CLEO effort and in many instances have leadership roles on projects within the collaboration.

Cornell experimentalists are also laying the groundwork for the future International Linear Collider or ILC. Taking advantage of the precision available to electron colliders, the ILC will zoom in on the phenomena discovered at the LHC, ruling out some possible explanations, and ruling in others. If dark matter candidates are there, it will determine their properties, and it will shed light on the unification of forces. Cornell physicists are developing detectors for the ILC, and are studying its physics reach.

There is a close coupling between the interests of the particle experimentalists and Cornell’s particle theory group for many aspects of the experimental program. This can lead to lively interactions, discussion and collaboration at all levels from faculty to graduate students.