A measurement of the production cross-section for top quark pairs (tt ??) in pp collisions at ???s = 7 TeV is presented using data recorded with the ATLAS detector at the Large Hadron Collider. Events are selected in two dif- ferent topologies: single lepton (electron e or muon ??) with large missing transverse energy and at least four jets, and dilepton (ee, ???? or e??) with large missing transverse en- ???1 ergy and at least two jets. In a data sample of 2.9 pb , 37 candidate events are observed in the single-lepton topology and 9 events in the dilepton topology. The corresponding ex- pected backgrounds from non-tt ?? Standard Model processes are estimated using data-driven methods and determined to be 12.2 ± 3.9 events and 2.5 ± 0.6 events, respectively. The kinematic properties of the selected events are consistent with SM tt ?? production. The inclusive top quark pair pro- duction cross-section is measured to be +42 ??tt ?? = 145 ± 31(stat.)???27(syst.) pb. The measurement agrees with perturbative QCD calcula- tions.
Measurement of the top quark-pair production cross section with ATLAS in pp collisions at $\sqrt{s}=7$ TeV / Aad, G; Aloisio, Alberto; Alviggi, Mariagrazia; Canale, Vincenzo; Cevenini, Francesco; Chiefari, Giovanni; DELLA VOLPE, Domenico; Merola, Leonardo; Patricelli, Sergio; Conventi, F.; DELLA PIETRA, Massimo; Giordano, Raffaele; Musto, E.; Rossi, E.; Sanchez, A.; Carlino, G.; de Asmundis, R.; Doria, A.; Izzo, V.; Sekhniaidze, G.. - In: THE EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS. - ISSN 1434-6044. - 71:(2011), pp. 1577-1612. [10.1140/epjc/s10052-011-1577-6]
Measurement of the top quark-pair production cross section with ATLAS in pp collisions at $\sqrt{s}=7$ TeV
ALOISIO, ALBERTO;ALVIGGI, MARIAGRAZIA;CANALE, VINCENZO;CEVENINI, FRANCESCO;CHIEFARI, GIOVANNI;DELLA VOLPE, DOMENICO;MEROLA, LEONARDO;PATRICELLI, SERGIO;DELLA PIETRA, MASSIMO;GIORDANO, RAFFAELE;Rossi E.;
2011
Abstract
A measurement of the production cross-section for top quark pairs (tt ??) in pp collisions at ???s = 7 TeV is presented using data recorded with the ATLAS detector at the Large Hadron Collider. Events are selected in two dif- ferent topologies: single lepton (electron e or muon ??) with large missing transverse energy and at least four jets, and dilepton (ee, ???? or e??) with large missing transverse en- ???1 ergy and at least two jets. In a data sample of 2.9 pb , 37 candidate events are observed in the single-lepton topology and 9 events in the dilepton topology. The corresponding ex- pected backgrounds from non-tt ?? Standard Model processes are estimated using data-driven methods and determined to be 12.2 ± 3.9 events and 2.5 ± 0.6 events, respectively. The kinematic properties of the selected events are consistent with SM tt ?? production. The inclusive top quark pair pro- duction cross-section is measured to be +42 ??tt ?? = 145 ± 31(stat.)???27(syst.) pb. The measurement agrees with perturbative QCD calcula- tions.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.