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 $35.9{\text{fb}}^{-1}$ of LHC proton-proton collision data collected with the CMS detector at $\sqrt{s}=13\text{TeV}$ . 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 $m_t=172.34\pm 0.20\text{(stat+JSF)}\pm 0.70\text{(syst)}\text{GeV}$ 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 $172.26\pm 0.07\text{(stat+JSF)}\pm 0.61\text{(syst)}\text{GeV}$ . This is the first combined $m_t$ extraction from the lepton+jets and all-jets channels through a single likelihood function.