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 μ) with large missing transverse energy and at least four jets, and dilepton (ee, μμ or eμ) 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 σtt ̄ = 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
CACCIA, MASSIMO;
2011-01-01
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 μ) with large missing transverse energy and at least four jets, and dilepton (ee, μμ or eμ) 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 σtt ̄ = 145 ± 31(stat.)−27(syst.) pb. The measurement agrees with perturbative QCD calcula- tions.File | Dimensione | Formato | |
---|---|---|---|
ATLAS_TOP.pdf
accesso aperto
Tipologia:
Documento in Post-print
Licenza:
DRM non definito
Dimensione
2.58 MB
Formato
Adobe PDF
|
2.58 MB | Adobe PDF | Visualizza/Apri |
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.