Measurement of the top quark pole mass using t t ¯+jet events in the dilepton final state in proton-proton collisions at √s = 13 TeV

A measurement of the top quark pole mass m _t ^pole in events where a top quark-antiquark pair (tt¯) is produced in association with at least one additional jet (tt¯+jet) is presented. This analysis is performed using proton-proton collision data at s = 13 TeV collected by the CMS experiment at the CERN LHC, corresponding to a total integrated luminosity of 36.3 fb ⁻¹. Events with two opposite-sign leptons in the final state (e ⁺e ⁻, μ ⁺μ ⁻, e ^±μ ^∓) are analyzed. The reconstruction of the main observable and the event classification are optimized using multivariate analysis techniques based on machine learning. The production cross section is measured as a function of the inverse of the invariant mass of the tt¯+jet system at the parton level using a maximum likelihood unfolding. Given a reference parton distribution function (PDF), the top quark pole mass is extracted using the theoretical predictions at next-to-leading order. For the ABMP16NLO PDF, this results in m _t ^pole = 172.93 ± 1.36 GeV.