Measurement of the top-quark mass in t t-bar events with dilepton final states in pp collisions at sqrt(s)=7 TeV

TL;DR

This paper reports a precise measurement of the top-quark mass in proton-proton collisions at 7 TeV using dilepton decay channels, employing a matrix weighting technique and maximum-likelihood fit, with results consistent with previous measurements.

Contribution

It introduces an analytical matrix weighting method combined with a maximum-likelihood fit to accurately determine the top-quark mass in dilepton events at the LHC.

Findings

Top-quark mass measured as 172.5 GeV

Statistical uncertainty of 0.4 GeV

Systematic uncertainty of 1.5 GeV

Abstract

The top-quark mass is measured in proton-proton collisions at sqrt(s) = 7 TeV using a data sample corresponding to an integrated luminosity of 5.0 inverse femtobarns collected by the CMS experiment at the LHC. The measurement is performed in the dilepton decay channel t t-bar to ell+ nu[ell] b, ell- anti-nu[ell] b-bar, where ell=e,mu. 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.