Observation of tW production in the single-lepton channel in pp collisions at $\sqrt{s}$ = 13 TeV

TL;DR

This paper reports the first observation of the tW production process in proton-proton collisions at 13 TeV, using CMS data, with a significance over 5 sigma and a measured cross section consistent with the Standard Model.

Contribution

It presents the first observation of tW production in final states with a muon or electron and jets at 13 TeV, employing advanced data analysis techniques.

Findings

First observation of tW process with >5 sigma significance.

Measured cross section of 89 ± 4 (stat) ± 12 (syst) pb.

Results are consistent with Standard Model predictions.

Abstract

A measurement of the cross section of the associated production of a single top quark and a W boson in final states with a muon or electron and jets in proton-proton collisions at $\sqrt{s}$ = 13 TeV is presented. The data correspond to an integrated luminosity of 36 fb$^{-1}$ collected with the CMS detector at the CERN LHC in 2016. A boosted decision tree is used to separate the tW signal from the dominant $\mathrm{t\bar{t}}$ background, whilst the subleading W+jets and multijet backgrounds are constrained using data-based estimates. This result is the first observation of the tW process in final states containing a muon or electron and jets, with a significance exceeding 5 standard deviations. The cross section is determined to be 89 $\pm$ 4 (stat) $\pm$ 12 (syst) pb, consistent with the standard model.