Search for s-channel single top-quark production in pp collisions at 8 TeV with the CMS experiment at the LHC

A search for single top-quark production in the s channel in proton-proton collisions at a centre-of-mass energy of $\sqrt{s}$ = 8 TeV by the CMS detector at the LHC is presented. Leptonic decay modes of the top quark with an electron or muon in the final state are considered. The signal is extracted by performing a maximum-likelihood fit to the distribution of a multivariate discriminant defined using Boosted Decision Trees to separate the expected signal contribution from the background processes. Data collected in 2012, corresponding to an integrated luminosity of 19.3/fb, lead to an upper limit on the cross section times branching ratio of 11.5 pb at 95\% confidence level.