10.1140-epjc-s10052-014-3109-7.pdf (1.44 MB)
Measurement of the tt¯ production cross-section using eµ events with b-tagged jets in pp collisions at vs=7 and 8 TeV with the ATLAS detector
journal contribution
posted on 2023-06-09, 06:07 authored by Benedict AllbrookeBenedict Allbrooke, Lily AsquithLily Asquith, Alessandro CerriAlessandro Cerri, C A Chavez Barajas, Antonella De SantoAntonella De Santo, Fabrizio SalvatoreFabrizio Salvatore, I Santoyo Castillo, K Suruliz, Mark SuttonMark Sutton, Iacopo Vivarelli, et al. The ATLAS CollaborationThe inclusive top quark pair (tt¯) production cross-section stt¯ has been measured in proton–proton collisions at vs=7 TeV and vs=8 TeV with the ATLAS experiment at the LHC, using tt¯ events with an opposite-charge eµ pair in the final state. The measurement was performed with the 2011 7 TeV dataset corresponding to an integrated luminosity of 4.6 fb-1 and the 2012 8 TeV dataset of 20.3 fb-1. The numbers of events with exactly one and exactly two b-tagged jets were counted and used to simultaneously determine stt¯ and the efficiency to reconstruct and b-tag a jet from a top quark decay, thereby minimising the associated systematic uncertainties. The cross-section was measured to be: stt¯=182.9±3.1±4.2±3.6±3.3 pb (s=7 TeV)and stt¯=242.4±1.7±5.5±7.5±4.2 pb (s=8 TeV), where the four uncertainties arise from data statistics, experimental and theoretical systematic effects, knowledge of the integrated luminosity and of the LHC beam energy. The results are consistent with recent theoretical QCD calculations at next-to-next-to-leading order. Fiducial measurements corresponding to the experimental acceptance of the leptons are also reported, together with the ratio of cross-sections measured at the two centre-of-mass energies. The inclusive cross-section results were used to determine the top quark pole mass via the dependence of the theoretically predicted cross-section on mtpole giving a result of mtpole=172.9-2.6+2.5 GeV. By looking for an excess of tt¯ production with respect to the QCD prediction, the results were also used to place limits on the pair-production of supersymmetric top squarks t~1 with masses close to the top quark mass, decaying via t~1?t?~10 to predominantly right-handed top quarks and a light neutralino ?~10, the lightest supersymmetric particle. Top squarks with masses between the top quark mass and 177 GeV are excluded at the 95 % confidence level.
Funding
ATLAS; G0275; STFC-SCIENCE AND TECHNOLOGY FACILITIES COUNCIL; ST/I006048/1
History
Publication status
- Published
File Version
- Published version
Journal
European Physical Journal C: Particles and FieldsISSN
1434-6044Publisher
Springer VerlagExternal DOI
Issue
3109Volume
74Department affiliated with
- Physics and Astronomy Publications
Research groups affiliated with
- Experimental Particle Physics Research Group Publications
Full text available
- Yes
Peer reviewed?
- Yes
Legacy Posted Date
2017-05-05First Open Access (FOA) Date
2017-05-05First Compliant Deposit (FCD) Date
2017-05-05Usage metrics
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