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

Abstract

A top quark mass measurement is performed using 35.9 fb−1 of LHC proton–proton collision data collected with the CMS detector at √ s = 13 TeV. The measurement uses the tt all-jets final state. A kinematic fit is performed to reconstruct the decay of the tt system and suppress themultijet 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 lepton+jets and all-jets final states is presented, using the same mass extraction method, and provides an mt measurement of 172.26 ± 0.07 (stat+JSF) ± 0.61 (syst) GeV. This is the first combined mt extraction from the lepton+jets and all-jets channels through a single likelihood function.