Measurement of inclusive and differential cross sections for single top quark production in association with a W boson in proton-proton collisions at $\sqrt{s}$ = 13 TeV

TL;DR

This paper reports precise measurements of the production rates and distributions of single top quarks with a W boson at 13 TeV, confirming the Standard Model predictions using CMS data from 2016-2018.

Contribution

It provides the first detailed differential cross section measurements for single top plus W production at 13 TeV with high precision.

Findings

Measured inclusive cross section of 79.2 pb with uncertainties.

Differential distributions agree with NLO QCD predictions.

Results are consistent with Standard Model expectations.

Abstract

Measurements of the inclusive and normalised differential cross sections are presented for the production of single top quarks in association with a W boson in proton-proton collisions at a centre-of-mass energy of 13 TeV. The data used were recorded with the CMS detector at the LHC during 2016-2018, and correspond to an integrated luminosity of 138 fb$^{-1}$. Events containing one electron and one muon in the final state are analysed. For the inclusive measurement, a multivariate discriminant, exploiting the kinematic properties of the events is used to separate the signal from the dominant $\mathrm{t\bar{t}}$ background. A cross section of 79.2 $\pm$ 0.9 (stat) $^{+7.7}_{-8.0}$ (syst) $\pm$ 1.2 (lumi) pb is obtained, consistent with the predictions of the standard model. For the differential measurements, a fiducial region is defined according to the detector acceptance, and the requirement of exactly one jet coming from the fragmentation of a bottom quark. The resulting distributions are unfolded to particle level and agree with the predictions at next-to-leading order in perturbative quantum chromodynamics.