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

In: Physics Letters B, Vol. 761, 10.10.2016, p. 136–157.

Research output: Contribution to journalArticle

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  • The ATLAS Collaboration

Abstract

This paper describes a measurement of the inclusive top quark pair production cross-section (σtt¯) 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 σtt¯ 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:

σtt¯=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.
Original languageEnglish
Pages (from-to)136–157
Number of pages22
JournalPhysics Letters B
Volume761
Early online date16 Aug 2016
DOIs
Publication statusPublished - 10 Oct 2016
This open access research output is licenced under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

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