Single Top associated tW production at 8 TeV in the two lepton final state

The observation of the associated production of a single top quark and W boson in pp collisions at $\sqrt{s}$ = 8 TeV with the CMS experiment at the LHC is presented. The analyzed data corresponds to an integrated luminosity of 12.2 $\mathrm{fb^{-1}}$. 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 signal from the $t\bar{t}$ background. The signal is observed with a 6.0 standard deviations excess above a background only hypothesis. A production cross section of $23.4^{+5.5}_{-5.4}$ pb is measured, in agreement with the standard model expectation of $22.2\pm1.5$ pb.