Measurement of the top quark mass in the all-jets final state at √s=13TeV and combination with the lepton+jets channel

Abstract

A top quark mass measurement is performed using 35.9fb−1of LHC proton–proton collision data collected with the CMS detector at √s=13TeV. The measurement uses the tt¯ all-jets final state. A kinematic fit is performed to reconstruct the decay of the tt¯ system and suppress the multijet background. Using the ideogram method, the top quark mass (mt) is determined, simultaneously constraining an additional jet energy scale factor (JSF). The resulting value of mt=172.34±0.20(stat+JSF)±0.70(syst)GeV is in good agreement with previous measurements. In addition, a combined measurement that uses the tt¯tt¯ lepton+jets and all-jets final states is presented, using the same mass extraction method, and provides an mtmt measurement of 172.26±0.07(stat+JSF)±0.61(syst)GeV. This is the first combined mtmt extraction from the lepton+jets and all-jets channels through a single likelihood function.