Search for s-channel single top-quark production in pp collisions

A search for single top-quark production in the s channel in proton-proton collisions at a centreof-mass energy of 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 95pct confidence level. Presented at EPS-HEP 2015 European Physical Society Conference on High Energy Physics 2015 Search for s-channel single top-quark production in pp collisions Mario Merola∗ for the CMS Collaboration INFN, Napoli (IT) E-mail: mario.merola@cern.ch A search for single top-quark production in the s channel in proton-proton collisions at a centre-ofmass energy of √ 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−1, leads to an upper limit on the cross section times branching ratio of 11.5 pb at 95% confidence level. The European Physical Society Conference on High Energy Physics 22-29 July 2015 Vienna, Austria