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 ${\mathrm {t}\overline{\mathrm {t}}}$ all-jets final state. A kinematic fit is performed to reconstruct the decay of the ${\mathrm {t}\overline{\mathrm {t}}}$ system and suppress the multijet background. Using the ideogram method, the top quark mass $(m_{\mathrm {t}})$ is determined, simultaneously constraining an additional jet energy scale factor $(\text {JSF})$. The resulting value of $m_{\mathrm {t}} =172.34\pm 0.20\,\text {(stat+JSF)} \pm 0.70\,\text {(syst)} \,\text {GeV}$ is in good agreement with previous measurements. In addition, a combined measurement that uses the ${\mathrm {t}\overline{\mathrm {t}}}$ lepton+jets and all-jets final states is presented, using the same mass extraction method, and provides an $m_{\mathrm {t}}$ measurement of $172.26\pm 0.07\,\text {(stat+JSF)} \pm 0.61\,\text {(syst)} \,\text {GeV}$. This is the first combined $m_{\mathrm {t}}$ extraction from the lepton+jets and all-jets channels through a single likelihood function.