Search for FCNC single top-quark production at sqrt(s) = 7 TeV with the ATLAS detector

G. Aad , S. Albrand (1) , M.L. Andrieux (1) , Q. Buat (1) , B. Clement (1) , J. Collot (1) , S. Crépé-Renaudin (1) , T. Delemontex (1) , P.A. Delsart (1) , M.H. Genest (1) , J.Y. Hostachy (1) , E. Laisne (1) , F. Ledroit-Guillon (1) , A. Lleres (1) , A. Lucotte (1) , F. Malek (1) , P. Martin (1) , F. Polci (1) , J. Stark (1) , X. Sun (1) , B. Trocmé (1) , J. Wang (1) , C. Weydert (1) , C. Biscarat (2) , E. Cogneras (2) , G. Rahal (2) , S. Abdel Khalek (3) , H. Abreu (3) , N. Andari (3) , C. Arnault (3) , E. Augé (3) , P. Barrillon (3) , M. Benoit (3) , S. Binet (3) , C. Bourdarios (3) , C. Collard (3) , C. de La Taille (3) , J.B. de Vivie de Regie (3) , L. Duflot (3) , M. Escalier (3) , L. Fayard (3) , D. Fournier (3) , J.-F. Grivaz (3) , S. Henrot-Versillé (3) , J. Hrivnac (3) , L. Iconomidou-Fayard (3) , J. Idarraga (3) , M. Kado (3) , N. Lorenzo Martinez (3) , A. Lounis (3) , N. Makovec (3) , P. Matricon (3) , F. Niedercorn (3) , L. Poggioli (3) , P. Puzo (3) , A. Renaud (3) , D. Rousseau (3) , G. Rybkin (3) , J.B. Sauvan (3) , J. Schaarschmidt (3) , A.C. Schaffer (3) , E. Scifo (3) , L. Serin (3) , S. Simion (3) , R. Tanaka (3) , M. Teinturier (3) , J.J. Veillet (3) , I. Vukotic (3) , F. Wicek (3) , D. Zerwas (3) , Z. Zhang (3) , D. Boumediene (4) , Emmanuel Busato (4) , D. Calvet (4) , S. Calvet (4) , Reina Coromoto Camacho Toro (4) , Diane Cinca (4) , J. Donini (4) , R. Febbraro (4) , N. Ghodbane (4) , C. Guicheney (4) , H. Liao (4) , D. Pallin (4) , F. Podlyski (4) , C. Santoni (4) , L. P. Says (4) , F. Vazeille (4) , L. Aperio Bella (5) , B. Aubert (5) , N. Berger (5) , J. Colas (5) , M. Delmastro (5) , L. Di Ciaccio (5) , T.K.O. Doan (5) , S. Elles (5) , C. Goy (5) , L. Helary (5) , T. Hryn'Ova (5) , A. Jérémie (5) , S. Jézéquel (5) , M. Kataoka (5) , J. Labbe (5) , R. Lafaye (5) , J. Leveque (5) , V.P. Lombardo (5) , N. Massol (5) , P. Perrodo (5) , E. Petit (5) , H. Przysiezniak (5) , G. Sauvage (5) , E. Sauvan (5) , M. Schwoerer (5) , T. Todorov (5) , D. Tsionou (5) , I. Wingerter-Seez (5) , R. Zitoun (5) , Y. Zolnierowski (5) , S. Aoun (6) , C. P. Bee (6) , C. Benchouk (6) , C. Bertella (6) , N. Bousson (6) , J. C. Clémens (6) , Y. Coadou (6) , F. Djama (6) , F. Etienne (6) , L. Feligioni (6) , F. Henry-Couannier (6) , D. Hoffmann (6) , F. Hubaut (6) , E. B. F. G. Knoops (6) , E. Le Guirriec (6) , B. Li (6) , J. Maurer (6) , E. Monnier (6) , J. Odier (6) , P. Pralavorio (6) , Z. Qian (6) , A. Rozanov (6) , M. Talby (6) , N. Tannoury (6) , S. Tisserant (6) , J. Toth (6) , F. Touchard (6) , L. Vacavant (6) , F. Vannucci (7)

1 LPSC - Laboratoire de Physique Subatomique et de Cosmologie
2 CC-IN2P3 - Centre de Calcul de l'IN2P3
3 LAL - Laboratoire de l'Accélérateur Linéaire
4 LPC - Laboratoire de Physique Corpusculaire - Clermont-Ferrand
5 LAPP - Laboratoire d'Annecy de Physique des Particules
6 CPPM - Centre de Physique des Particules de Marseille
7 APC - Neutrinos

Results on the search for flavor-changing neutral-current single top-quark production are reported. Data collected with the ATLAS detector at a center-of-mass energy of sqrt(s) = 7 TeV and corresponding to an integrated luminosity of 2.05 fb^-1 are used. Candidate events with a leptonic top-quark decay signature are classified into signal- and background-like events using a neural network. No signal is observed in the output distribution and a Bayesian upper limit on the production cross-section is placed. The observed 95% C.L. upper limit on the cross-section multiplied by the t -> Wb branching fraction is measured to be sigma(qg -> t) x B(t -> Wb) < 3.9 pb. This upper limit can be converted into an upper limit of the coupling strength k_ugt/Lambda < 6.9 x 10^-3 TeV^-1 and k_cgt/Lambda < 1.6 x 10^-2 TeV^-1 and on the branching fractions B(t -> ug) < 5.7 x 10^-5 and B(t -> cg) < 2.7 x 10^-4.

Domaines: Physique des Hautes Energies - Expérience [hep-ex]

G. Aad, S. Albrand, M.L. Andrieux, Q. Buat, B. Clement, et al.. Search for FCNC single top-quark production at sqrt(s) = 7 TeV with the ATLAS detector. Physics Letters B, 2012, 712, pp.351-369. ⟨10.1016/j.physletb.2012.05.022⟩. ⟨in2p3-00676315⟩