Student High Energy Physics Seminar: Lucie Gauthier
Title: Looking for direct stop production at the LHC with the CMS experiment & “razor” variables
Abstract: With the observation of the Higgs boson by both ATLAS & CMS experiments, a major objective of the LHC has been fulfilled. Yet, questions remain within the standard model of particle physics hopefully within the reach of the LHC. What is Dark Matter? How come the Higgs mass is not heavy? Supersymmetry is one of the candidate theory that could provide answers. Assuming R-parity conservation, supersymmetric particles are expected to be pair produced, with decay chains that end up with a particle that escapes the detector unseen. As a result, it is impossible to fully reconstruct a susy-like event and look for new particles as resonances in a way similar to what can be done for the Z boson, J/psi, etc... To address this challenging aspect of supersymmetric searches, one may try to build kinematic variables that probe the new physics. In particular, the "razor" variable MR allows to formulate the search for new physics as a search for a bump peaking over a steeply falling background.