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 \(35.9\phantom{\rule{0.166667em}{0ex}}{\text{fb}}^{-1}\) of LHC proton–proton collision data collected with the CMS detector at \(\sqrt{s}=13\phantom{\rule{0.166667em}{0ex}}\text{TeV}\). The measurement uses the \(t\overline{t}\) all-jets final state. A kinematic fit is performed to reconstruct the decay of the \(t\overline{t}\) system and suppress the multijet background. Using the ideogram method, the top quark mass ( \({m}_{t}\) ) is determined, simultaneously constraining an additional jet energy scale factor ( \(\text{JSF}\) ). The resulting value of \({m}_{t}=172.34±0.20\phantom{\rule{0.166667em}{0ex}}\text{(stat+JSF)}±0.70\phantom{\rule{0.166667em}{0ex}}\text{(syst)}\phantom{\rule{0.166667em}{0ex}}\text{GeV}\) is in good agreement with previous measurements. In addition, a combined measurement that uses the \(t\overline{t}\) lepton+jets and all-jets final states is presented, using the same mass extraction method, and provides an \({m}_{t}\) measurement of \(172.26±0.07\phantom{\rule{0.166667em}{0ex}}\text{(stat+JSF)}±0.61\phantom{\rule{0.166667em}{0ex}}\text{(syst)}\phantom{\rule{0.166667em}{0ex}}\text{GeV}\). This is the first combined \({m}_{t}\) extraction from the lepton+jets and all-jets channels through a single likelihood function.