Measurement of the top-quark mass in all-jets t t-bar events in pp collisions at sqrt(s) = 7 TeV

TL;DR

This paper reports a precise measurement of the top-quark mass using all-jets t t-bar events from 7 TeV proton-proton collisions, employing a kinematic fit and combining with previous results for improved accuracy.

Contribution

It introduces a measurement of the top-quark mass in all-jets decay mode using CMS data, and combines it with earlier measurements for enhanced precision.

Findings

Top-quark mass measured as 173.54 GeV with combined uncertainties.

Used a kinematic fit to reconstruct the top-quark mass in all-jets events.

Achieved improved precision by combining multiple decay mode measurements.

Abstract

The mass of the top quark is measured using a sample of t t-bar candidate events with at least six jets in the final state. The sample is selected from data collected with the CMS detector in pp collisions at sqrt(s) = 7 TeV in 2011 and corresponds to an integrated luminosity of 3.54 inverse femtobarns. The mass is reconstructed for each event employing a kinematic fit of the jets to a t t-bar hypothesis. The top-quark mass is measured to be 173.49 +/- 0.69 (stat.) +/- 1.21 (syst.) GeV. A combination with previously published measurements in other decay modes by CMS yields a mass of 173.54 +/- 0.33 (stat.) +/- 0.96 (syst.) GeV.