Measurement of the tt¯ production cross-section using eμ events with b-tagged jets in pp collisions at √s=13TeV with the ATLAS detector

This paper describes a measurement of the inclusive top quark pair production cross-section (σ tt¯ ) with a data sample of 3.2fb −1 of proton–proton collisions at a centre-of-mass energy of s=13TeV, collected in 2015 by the ATLAS detector at the LHC. This measurement uses events with an opposite-cha...

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Autor principal: Aaboud, M.
Formato: JOUR
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_03702693_v761_n_p136_Aaboud
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Sumario:This paper describes a measurement of the inclusive top quark pair production cross-section (σ tt¯ ) with a data sample of 3.2fb −1 of proton–proton collisions at a centre-of-mass energy of s=13TeV, collected in 2015 by the ATLAS detector at the LHC. This measurement uses events with an opposite-charge electron–muon pair in the final state. Jets containing b-quarks are tagged using an algorithm based on track impact parameters and reconstructed secondary vertices. The numbers of events with exactly one and exactly two b-tagged jets are counted and used to determine simultaneously σ tt¯ and the efficiency to reconstruct and b-tag a jet from a top quark decay, thereby minimising the associated systematic uncertainties. The cross-section is measured to be: σ tt¯ =818±8(stat)±27(syst)±19(lumi)±12(beam) pb, where the four uncertainties arise from data statistics, experimental and theoretical systematic effects, the integrated luminosity and the LHC beam energy, giving a total relative uncertainty of 4.4%. The result is consistent with theoretical QCD calculations at next-to-next-to-leading order. A fiducial measurement corresponding to the experimental acceptance of the leptons is also presented. © 2016 The Author(s)