Measurement of the ttproduction cross-section using eμ events with b-tagged jets in ppcollisions at √s=13 TeV with the ATLAS detector
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This paper describes a measurement of the inclusive top quark pair production cross-section (σtt̄) with a data sample of 3.2 fb−1of proton-proton collisions at a centre-of-mass energy of √s=13 TeV, 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 σtt̄and 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: σtt̄ = 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).
|Enheter & grupper|
Ämnesklassifikation (UKÄ) – OBLIGATORISK
|Tidskrift||Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics|
|Status||Published - 2016|
|Peer review utförd||Ja|