Evidence for associated production of a single top quark and W boson in $pp$ collisions at $\sqrt{s}$ = 7 TeV

Abstract

Evidence is presented for the associated production of a single top quark and W boson in pp collisions at √s=7 TeV with the CMS experiment at the LHC. The analyzed data correspond to an integrated luminosity of 4.9 fb$^{-1}$. 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 $t\bar{t}$ background from the signal. The observed signal has a significance of 4.0σ and corresponds to a cross section of 16$_{-4}^{+5}$ pb, in agreement with the standard model expectation of 15.6±0.4$_{-1.2}^{+1.0}$ pb.