Measurement of Top Quark Pair Production Cross section at √s = 7 TeV and Estimation of Top Quark Mass using CMS Data

High center-of-mass energies at the LHC result in the production of a lot of top quarks, the heaviest elementary particle in the Standard Model. This makes data collected from LHC collisions ideal for studying properties of the top quark and its production cross section at LHC energy ranges. The cross section of top quark pair production from proton-proton collisions at √s = 7 TeV is measured from $50\ \textrm{pb}^{-1}$ of CMS data collected in 2011 at the LHC. The analysis is performed using the semi-leptonic (lepton+jets) decay channel of tt̄ pair. Hence, the mass of the top quark is estimated by reconstructing the final decay products and finding the mass distribution of the reconstructed top quark pair.