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Measurement of the charge asymmetry in highly boosted top-quark pair production in $\sqrt{s} =$ 8 TeV $pp$ collision data collected by the ATLAS experiment

A measurement of the charge asymmetry reflecting the different rapidity distribution of top and anti-top quarks in the production of high invariant mass top-quark pairs is presented using 20.3 fb$^{-1}$ of $\sqrt{s}$ = 8 TeV proton-proton collisions collected by the ATLAS experiment at the LHC. The...

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Detalles Bibliográficos
Autor principal: The ATLAS collaboration
Lenguaje:eng
Publicado: 2015
Materias:
Acceso en línea:http://cds.cern.ch/record/2052587
Descripción
Sumario:A measurement of the charge asymmetry reflecting the different rapidity distribution of top and anti-top quarks in the production of high invariant mass top-quark pairs is presented using 20.3 fb$^{-1}$ of $\sqrt{s}$ = 8 TeV proton-proton collisions collected by the ATLAS experiment at the LHC. The analysis is based on an event reconstruction and selection criteria, specifically designed for highly boosted top quarks, that uses jet substructure to identify the top-quark candidate, which decays to a fully hadronic final state. The charge asymmetry in a fiducial region with large invariant mass of the top-quark pair ($m_{t\bar{t}} > $ 0.75 TeV) and an absolute rapidity difference within -2 $< \Delta |y| <$ 2 is measured to be 4.2 $\pm$ 3.2%, in agreement with the Standard Model prediction at next-to-leading order. A differential measurement in three $t\bar{t}$ mass bins is also presented.