Measurement of the top quark mass in the dileptonic tt¯ decay channel using the mass observables Mbℓ, MT2, and Mbℓν in pp collisions at s=8 TeV

2017/04/30 by A. M. Sirunyan, CMS Collaboration, A. Tumasyan +98
Physics and Astronomy · #High-Energy Particle Collisions Research #Large Hadron Collider #Lepton #Nuclear physics #Observable #Particle physics #Particle physics theoretical and experimental studies #Physics #Quantum Chromodynamics and Particle Interactions #Quantum mechanics #Quark #Top quark #hep-ex

paper · pdf · doi:10.1103/physrevd.96.032002

published as Phys. Rev. D 96, 032002 (2017) · Replaced with the published version. Added the journal reference and DOI. All figures and tables can be found at http://cms-results.web.cern.ch/cms-results/public-results/publications/TOP-15-008

openalex created_date 2017/05/19 · openalex publication_date 2017/08/22 · arxiv created 2017/08/26 · arxiv updated 2017/08/30 · openalex updated_date 2026/08/06

Abstract

A measurement of the top quark mass (M_t) 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\ifmmode±\else\textpm\fi0.5 fb^\ensuremath-1. Events are selected with two oppositely charged leptons (\ensuremathℓ=e, \ensuremathμ) 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 M_t. An invariant mass observable, M_b\ensuremathℓ, 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_b\ensuremathℓ\ensuremathν, 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\ifmmode±\else\textpm\fi0.18(stat) _\ensuremath-0.93^+0.89(syst) GeV.

Citations

• MT2-assisted on-shell reconstruction of missing momenta and its application to spin measurement at the LHC
• The anti-ktjet clustering algorithm
• Study of the fragmentation of b quarks into B mesons at the Z peak
• Measurement of the differential cross section for top quark pair production in pp collisions at √(s) = 8 \text TeV s = 8 TeV
• Higgs mass and vacuum stability in the Standard Model at NNLO
• Performance of electron reconstruction and selection with the CMS detector in proton-proton collisions at √s= 8 TeV
• Review of Multibody Charm Analyses