Measurement of the Top Quark Mass İn The Dileptonic t(t)over-bar Decay Channel Using The Mass Observables M-bl, M-T2, and M-blv in pp Collisions at Root=8 TeV
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2017
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American Physical Society Sites
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A measurement of the top quark mass (Mt) in the dileptonic tt decay channel is performed using data from proton-proton collisions at a center-of-mass energy of 8 TeV. The data was recorded by the CMS experiment at the LHC and corresponds to an integrated luminosity of 19.7 ± 0.5 fb?1 . Events are selected with two oppositely charged leptons (` = e, µ) and two jets identified as originating from b quarks. The analysis is based on three kinematic observables whose distributions are sensitive to the value of Mt . An invariant mass observable, Mb` , and a ‘stransverse mass’ observable, MT2, are employed in a simultaneous fit to determine the value of Mt and an overall jet energy scale factor (JSF). A complementary approach is used to construct an invariant mass observable, Mb`? , that is combined with MT2 to measure Mt . The shapes of the observables, along with their evolutions in Mt and JSF, are modeled by a nonparametric Gaussian process regression technique. The sensitivity of the observables to the value of Mt is investigated using a Fisher information density method. The top quark mass is measured to be 172.22 ± 0.18 (stat) +0.89 ?0.93 (syst) GeV.
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