%0 Journal Article %T Evidence for single top-quark production in the s-channel in proton-proton collisions at root s=8 TeV with the ATLAS detector using the Matrix Element Method %A ATLAS Collaboration (Aad, G. et al %A Alvarez Piqueras, D. %A Cabrera Urban, S. %A Castillo Gimenez, V. %A Cerda Alberich, L. %A Costa, M. J. %A Fernandez Martinez, P. %A Ferrer, A. %A Fiorini, L. %A Fuster, J. %A Garcia, C. %A Garcia Navarro, J. E. %A Gonzalez de la Hoz, S. %A Hernandez Jimenez, Y. %A Higon-Rodriguez, E. %A Irles Quiles, A. %A Jimenez Pena, J. %A Kaci, M. %A King, M. %A Lacasta, C. %A Lacuesta, V. R. %A Marti-Garcia, S. %A Mitsou, V. A. %A Pedraza Lopez, S. %A Perez Garcia-Estañ, M. T. %A Romero Adam, E. %A Ros, E. %A Salt, J. %A Sanchez Martinez, V. %A Soldevila, U. %A Sanchez, J. %A Valero, A. %A Valls Ferrer, J. A. %A Vos, M. %J Physics Letters B %D 2016 %V 756 %I Elsevier Science Bv %@ 0370-2693 %G English %F ATLASCollaborationAad_etal2016 %O WOS:000373569200035 %O exported from refbase (https://references.ific.uv.es/refbase/show.php?record=2634), last updated on Thu, 28 Jul 2016 12:27:43 +0000 %X This Letter presents evidence for single top-quark production in the s-channel using proton-proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS detector at the CERN Large Hadron Collider. The analysis is performed on events containing one isolated electron or muon, large missing transverse momentum and exactly two b-tagged jets in the final state. The analysed data set corresponds to an integrated luminosity of 20.3 fb(-1). The signal is extracted using a maximum-likelihood fit of a discriminant which is based on the matrix element method and optimized in order to separate single-top-quark s-channel events from the main background contributions, which are top-quark pair production and W boson production in association with heavy-flavour jets. The measurement leads to an observed signal significance of 3.2 standard deviations and a measured cross-section of sigma s = 4.8 +/- 0.8(stat.)(-1.3)(+1.6)(syst.) pb, which is consistent with the Standard Model expectation. The expected significance for the analysis is 3.9 standard deviations. %R 10.1016/j.physletb.2016.03.017 %U http://arxiv.org/abs/1511.05980 %U https://doi.org/10.1016/j.physletb.2016.03.017 %P 228-246