Measurement of the top-quark mass in tt̄ events with dilepton final states in pp collisions at √s=7 TeV

Abstract

The top-quark mass is measured in proton-proton collisions at √s = 7 TeV using a data sample corresponding to an integrated luminosity of 5. 0 fb-1 collected by the CMS experiment at the LHC. The measurement is performed in the dilepton decay channel tt̄ → (ℓ+νℓb)(ℓ-νℓB̄), where ℓ=e,μ. Candidate top-quark decays are selected by requiring two leptons, at least two jets, and imbalance in transverse momentum. The mass is reconstructed with an analytical matrix weighting technique using distributions derived from simulated samples. Using a maximum-likelihood fit, the top-quark mass is determined to be 172. 5±0. 4 (stat.)±1. 5 (syst.) GeV. © 2012 CERN for the benefit of the CMS collaboration.