Search for Supersymmetry in hadronic final states using MT2 with the CMS detector at 7 TeV

A search for Supersymmetry or similar new physics was carried out using a $\sqrt{s} = 7$ TeV $pp$ collisions data sample corresponding to \Lumino of integrated luminosity collected by the CMS experiment at the LHC. Fully hadronic final states were selected based on the stransverse mass variable $M_{T2}$. Two complementary analyses were performed. The first targets the region of parameter space with medium to high squark and gluino masses, in which the signal can be separated from the Standard Model backgrounds by a strong cut on $M_{T2}$. A second analysis has been optimized to look for events with a light gluino but heavy squarks. In this case, the $M_{T2}$ cut was relaxed, but a higher jet multiplicity and at least one $b$-tagged jet were required. The dominant backgrounds in both analyses are different and they were estimated using data-driven methods. As no excess of events over the expected background was observed, exclusion limits were derived on the parameter space of the constrained minimal supersymmetric extension of the Standard Model (mSUGRA/CMSSM), as well as on a variety of Simplified Model Spectra.