The t-channel process provides a unique phase space with lower colour reconnection probability as compared to tt-bar events, which has been exploited to make a precise measurement of the top quark mass. This channel is the most dominant process for single top quark production at the LHC. The resulting final-state comprises a single top along with a light quark giving rise to at least two jets, one of which arises from the hadronization of a b-quark, an isolated high-momentum lepton (electron or muon), and large missing momentum due to an escaping neutrino from the W decay. The study is based on proton-proton collision data, equivalent to 35.9 fb−1 integrated luminosity, recorded at √s = 13 TeV by the CMS experiment during 2016. Dominant standard model background processes are studied in different regions depending on the number of btagged and light-flavour jets in the final state. A multivariate technique relying on boosted decision trees is deployed to optimally separate the signal from backgrounds. The topquark mass is reconstructed using kinematic information of the final-state objects, namely charged lepton, missing momentum, and jets. We obtain the top quark mass by fitting its reconstructed mass distribution using an appropriate combination of parametric shapes. The measured mass of the top quark in t-channel is 172.13 ± 0.32 (stat+prof) +0.69-0.70 (syst) GeV.
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