Measurement of single top-quark production in the s-channel in proton–proton collisions at √s = 13 TeV with the ATLAS detector

Abstract

Abstract A measurement of single top-quark production in the s-channel is performed in proton–proton collisions at a centre-of-mass energy of 13 TeV with the ATLAS detector at the CERN Large Hadron Collider. The dataset corresponds to an integrated luminosity of 139 fb−1. The analysis is performed on events with an electron or muon, missing transverse momentum and exactly two b-tagged jets in the final state. A discriminant based on matrix element calculations is used to separate single-top-quark s-channel events from the main background contributions, which are top-quark pair production and W-boson production in association with jets. The observed (expected) signal significance over the background-only hypothesis is 3.3 (3.9) standard deviations, and the measured cross-section is $$ \sigma ={8.2}_{-2.9}^{+3.5} $$ σ = 8.2

− 2.9

+ 3.5

pb, consistent with the Standard Model prediction of $$ {\sigma}^{\textrm{SM}}={10.32}_{-0.36}^{+0.40} $$

σ SM

=

10.32

− 0.36

+ 0.40

pb.