Evidence for associated production of a single top quark and W boson in pp collisions at sqrt(s) = 7 TeV

TL;DR

This paper reports the first evidence for the production of a single top quark in association with a W boson in proton-proton collisions at 7 TeV, using CMS data and advanced analysis techniques.

Contribution

It provides the first evidence for tW associated production at the LHC, with a significance of 4.0 sigma and a measured cross section consistent with the standard model.

Findings

Observed signal significance of 4.0 sigma

Measured cross section of 16 +5 -4 pb

Results agree with standard model predictions

Abstract

Evidence is presented for the associated production of a single top quark and W boson in pp collisions at sqrt(s) = 7 TeV with the CMS experiment at the LHC. The analyzed data corresponds to an integrated luminosity of 4.9 inverse femtobarns. The measurement is performed using events with two leptons and a jet originated from a b quark. A multivariate analysis based on kinematic properties is utilized to separate the t t-bar background from the signal. The observed signal has a significance of 4.0 sigma and corresponds to a cross section of 16 +5 -4 pb, in agreement with the standard model expectation of 15.6 +/-0.4 +1.0 -1.2 pb.