Search for Supersymmetry in proton-proton collisions at sqrt_S=13 TeV with jets, b-jets and missing transverse momentum

Abstract

Standard Model of elementary particles (SM) explains various physical phenomena occurring in the world around us in the terms of participating fundamental particles and interactions among these particles. The particle family of the model is completed with the long sought Higgs boson of mass 125 GeV by the CMS and ATLAS experiments at the Large Hadron Collider in 2012. The SM, however, is largely accepted to be incomplete as it does not explain theoretical stability of the Higgs boson mass, or explain observed dark matter in the universe, or incorporate gravity to name a few. Many beyond SM theories are postulated to overcome limitations of the SM. One of such theories is Supersymmetry (SUSY). SUSY models predict a partner to every SM particle, which differs by spin half from the SM counterpart. These particles are expected to be more massive than their SM cousins. This thesis presents a search for SUSY in a final state with multiple jets, b-jets and large missing transverse momentum. The search is performed using 137 fb−1data collected by CMS experiment at LHC, over the years 2016, 2017 and 2018 using proton-proton collisions at centre of mass energy of 13 TeV. The SM events and different SUSY topologies which also give the same final state are considered. No signature for SUSY is found based on this analysis. The limits are put on different SUSY scenarios with squark and gluino pair production. Depending on model, gluinos with mass up to 2-2.3 TeV and squarks with mass 1.1-1.6 TeV are probed at 95% confidence level.