Measurement of the top quark mass in 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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Sirunyan A. M., Sirunyan A. M., Tumasyan A., Adam W., Asilar E., Bergauer T., ...More

PHYSICAL REVIEW D, vol.96, no.3, 2017 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 96 Issue: 3
  • Publication Date: 2017
  • Doi Number: 10.1103/physrevd.96.032002
  • Journal Name: PHYSICAL REVIEW D
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Istanbul University Affiliated: No

Abstract

A measurement of the top quark mass (M-t) in the dileptonic t (t) over bar 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 (l = e, mu) 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, M-bl, and a "stransverse mass" observable, M-T2, are employed in a simultaneous fit to determine the value of M-t and an overall jet energy scale factor (JSF). A complementary approach is used to construct an invariant mass observable, M-blv, that is combined with M-T2 to measure M-t. The shapes of the observables, along with their evolutions in M-t and JSF, are modeled by a nonparametric Gaussian process regression technique. The sensitivity of the observables to the value of M-t is investigated using a Fisher information density method. The top quark mass is measured to be 172.22 +/- 0.18(stat)(-0.93)(+0.89) (syst) GeV.