Measurement of the top quark-pair production cross section with ATLAS in pp collisions at $\sqrt{s}=7\TeV$

G. Aad , L. Aperio Bella (1) , B. Aubert (1) , M. Aurousseau (1) , N. Berger (1) , J. Colas (1) , L. Di Ciaccio (1) , M. El Kacimi (1) , S. Elles (1) , P. Ghez (1) , M. Gouanère (1) , C. Goy (1) , T. Guillemin (1) , L. Helary (1) , T. Hryn'Ova (1) , P. Iengo (1) , A. Jérémie (1) , S. Jézéquel (1) , J. Labbe (1) , R. Lafaye (1) , N. Massol (1) , P. Perrodo (1) , H. Przysiezniak (1) , G. Sauvage (1) , T. Todorov (1) , I. Wingerter-Seez (1) , R. Zitoun (1) , Y. Zolnierowski (1) , C. Biscarat (2) , E. Cogneras (2) , G. Rahal (2) , H. Bachacou (3) , F. Bauer (3) , N. Besson (3) , M. Boonekamp (3) , L. Chevalier (3) , F. Chevallier (3) , J. Ernwein (3) , A.I. Etienvre (3) , A. Formica (3) , L. Gauthier (3) , F. Giraud (3) , C. Guyot (3) , S. Hassani (3) , W. Kozanecki (3) , E. Lancon (3) , J.F. Laporte (3) , E. Le Menedeu (3) , B. Lenzi (3) , B. Mansoulie (3) , J.-P. Meyer (3) , N. Morange (3) , R. Nicolaidou (3) , A. Ouraou (3) , D.M. Pomarede (3) , B. Resende (3) , C.R. Royon (3) , Ph. Schune (3) , J. Schwindling (3) , M. Virchaux (3) , T.K.O. Doan (1) , S. Albrand , M.L. Andrieux (4) , M. Belhorma (4) , B. Clement (4) , J. Collot (4) , S. Crépé-Renaudin (4) , P. de Saintignon (4) , P.A. Delsart (4) , J. Donini (4) , Daniel Dzahini (4) , J.Y. Hostachy (4) , E. Laisne (4) , F. Ledroit-Guillon (4) , A. Lleres (4) , A. Lucotte (4) , F. Malek (4) , P. Martin (4) , F. Polci (4) , J. Stark (4) , X. Sun (4) , B. Trocmé (4) , S. Aoun (5) , C. Bee (5) , C. Benchouk (5) , K. Bernardet (5) , N. Boussons , C. Cerna (5) , J. C. Clémens (5) , Y. Coadou (5) , S. Correard (5) , P. Delpierre (5) , F. Etienne (5) , F. Henry-Couannier (5) , D. Hoffmann (5) , F. Hubaut (5) , M. Kuna (5) , E. Le Guirriec (5) , J. Lévêque (5) , B. Li (5) , E. Monnier (5) , J. Odier (5) , E. Petit (5) , P. Pralavorio (5) , Z. Qian (5) , A. Rozanov (5) , N. Tannoury (5) , J. Toth (5) , F. Touchard (5) , L. Vacavant (5) , H. Abreu (6) , N. Andari (6) , C. Arnault (6) , E. Augé (6) , P. Barrillon (6) , M. Benoit (6) , S. Binet (6) , J.-B. Blanchard (6) , C. Bourdarios (6) , D. Breton (6) , C. Collard (7) , C. de La Taille (6) , J.B. de Vivie de Regie (6) , Sara Diglio (6) , L. Duflot (6) , M. Escalier (6) , A.C. Falou (6) , L. Fayard (6) , D. Fournier (6) , J.-F. Grivaz (6) , M. Heller (6) , S. Henrot-Versillé (6) , J. Hrivnac (6) , L. Iconomidou-Fayard (6) , J. Idarraga (6) , M. Kado (6) , A. Lounis (6) , N. Makovec (6) , P. Matricon (6) , F. Niedercorn (6) , L. Poggioli (6) , P. Puzo (6) , A. Renaud (6) , D. Rousseau (6) , X. Ruan (6, 8) , G. Rybkin (6) , J.B. Sauvan (6) , J. Schaarschmidt (6) , A.C. Schaffer (6) , L. Serin (6) , S. Simion (6) , R. Tanaka (6) , J.J. Veillet (6) , I. Vukotic (6) , F. Wicek (6) , D. Zerwas (6) , Zhiqing Zhang (6)

1 LAPP - Laboratoire d'Annecy de Physique des Particules
2 CC-IN2P3 - Centre de Calcul de l'IN2P3
3 IRFU - Institut de Recherches sur les lois Fondamentales de l'Univers
4 LPSC - Laboratoire de Physique Subatomique et de Cosmologie
5 CPPM - Centre de Physique des Particules de Marseille
6 LAL - Laboratoire de l'Accélérateur Linéaire
7 IPHC - Institut Pluridisciplinaire Hubert Curien
8 IHEP - Institute of High Energy Physics

A measurement of the production cross-section for top quark pairs($\ttbar$) in $pp$ collisions at $\sqrt{s}=7 \TeV$ is presented using data recorded with the ATLAS detector at the Large Hadron Collider. Events are selected in two different topologies: single lepton (electron $e$ or muon $\mu$) with large missing transverse energy and at least four jets, and dilepton ($ee$, $\mu\mu$ or $e\mu$) with large missing transverse energy and at least two jets. In a data sample of 2.9 pb-1, 37 candidate events are observed in the single-lepton topology and 9 events in the dilepton topology. The corresponding expected backgrounds from non-$\ttbar$ Standard Model processes are estimated using data-driven methods and determined to be $12.2 \pm 3.9$ events and $2.5 \pm 0.6$ events, respectively. The kinematic properties of the selected events are consistent with SM $\ttbar$ production. The inclusive top quark pair production cross-section is measured to be $\sigmattbar=145 \pm 31 ^{+42}_{-27}$ pb where the first uncertainty is statistical and the second systematic. The measurement agrees with perturbative QCD calculations.

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

G. Aad, L. Aperio Bella, B. Aubert, M. Aurousseau, N. Berger, et al.. Measurement of the top quark-pair production cross section with ATLAS in pp collisions at $\sqrt{s}=7\TeV$. European Physical Journal C: Particles and Fields, 2011, 71, pp.1577. ⟨10.1140/epjc/s10052-011-1577-6⟩. ⟨in2p3-00553524⟩