학술논문
Search for s-channel single top-quark production in proton-proton collisions at √s=8 TeV with the ATLAS detector
Document Type
article
Author
Aad, G; Abbott, B; Abdallah, J; Abdel Khalek, S; Abdinov, O; Aben, R; Abi, B; Abolins, M; AbouZeid, OS; Abramowicz, H; Abreu, H; Abreu, R; Abulaiti, Y; Acharya, BS; Adamczyk, L; Adams, DL; Adelman, J; Adomeit, S; Adye, T; Agatonovic-Jovin, T; Aguilar-Saavedra, JA; Agustoni, M; Ahlen, SP; Ahmadov, F; Aielli, G; Akerstedt, H; Åkesson, TPA; Akimoto, G; Akimov, AV; Alberghi, GL; Albert, J; Albrand, S; Alconada Verzini, MJ; Aleksa, M; Aleksandrov, IN; Alexa, C; Alexander, G; Alexandre, G; Alexopoulos, T; Alhroob, M; Alimonti, G; Alio, L; Alison, J; Allbrooke, BMM; Allison, LJ; Allport, PP; Aloisio, A; Alonso, A; Alonso, F; Alpigiani, C; Altheimer, A; Alvarez Gonzalez, B; Alviggi, MG; Amako, K; Amaral Coutinho, Y; Amelung, C; Amidei, D; Amor Dos Santos, SP; Amorim, A; Amoroso, S; Amram, N; Amundsen, G; Anastopoulos, C; Ancu, LS; Andari, N; Andeen, T; Anders, CF; Anders, G; Anderson, KJ; Andreazza, A; Andrei, V; Anduaga, XS; Angelidakis, S; Angelozzi, I; Anger, P; Angerami, A; Anghinolfi, F; Anisenkov, AV; Anjos, N; Annovi, A; Antonaki, A; Antonelli, M; Antonov, A; Antos, J; Anulli, F; Aoki, M; Aperio Bella, L; Apolle, R; Arabidze, G; Aracena, I; Arai, Y; Araque, JP; Arce, ATH; Arduh, FA; Arguin, JF; Argyropoulos, S; Arik, M; Armbruster, AJ; Arnaez, O; Arnal, V
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Language
Abstract
This Letter presents a search at the LHC for s-channel single top-quark production in proton-proton collisions at a centre-of-mass energy of 8 TeV. The analyzed data set was recorded by the ATLAS detector and corresponds to an integrated luminosity of 20.3 fb-1. Selected events contain one charged lepton, large missing transverse momentum and exactly two b-tagged jets. A multivariate event classifier based on boosted decision trees is developed to discriminate s-channel single top-quark events from the main background contributions. The signal extraction is based on a binned maximum-likelihood fit of the output classifier distribution. The analysis leads to an upper limit on the s-channel single top-quark production cross-section of 14.6 pb at the 95% confidence level. The fit gives a cross-section of σs = 5.0 ± 4.3 pb, consistent with the Standard Model expectation.