Search for Single Top tW Associated Production in the Dilepton Channel at CMS

We present a first study of the single top quark W-associated production (tW) in proton-proton collisions at the LHC at a centre-of-mass energy of 7TeV, using data collected with the CMS experiment. The search is performed in the dileptonic final states ee/e$\mu$/$\mu\mu$ with a selection based on kinematical properties and b-tagging information. The contribution of the Z+jets processes to the background is estimated from a sideband in data. Two $\rm t\bar t$ dominated control regions are used to constrain the normalization of top quark pair production in the signal region. An excess of events over the expected background is observed. Assigning this excess to events from tW production, the extracted tW cross section is in agreement with the Standard Model expectation.