TY - JOUR
T1 - Measurement of the tt¯tt¯ production cross-section using eμeμ events with bb-tagged jets in pppp collisions at s√=7s=7 and 8 TeV with the ATLAS detector
AU - The ATLAS Collaboration
AU - Abbott, Brad
AU - Abdallah, Jalal
AU - Abdel Khalek, Samah
AU - Abdinov, Ovsat
AU - Aben, Rosemarie
AU - Abi, Babak
AU - Abolins, Maris
AU - AbouZeid, Ossama
AU - Abramowicz, Halina
AU - Abreu, Henso
AU - Abreu, Ricardo
AU - Abulaiti, Yiming
AU - Acharya, Bobby Sami
AU - Adamczyk, Leszek
AU - Adams, David
AU - Adelman, Jahred
AU - Adomeit, Stefanie
AU - Adye, Tim
AU - Agatonovic-Jovin, Tatjana
AU - Aguilar-Saavedra, Juan Anton
AU - Agustoni, Marco
AU - Ahlen, Steven
AU - Ahmadov, Faig
AU - Aielli, Giulio
AU - Akerstedt, Henrik
AU - Åkesson, Torsten Pa
AU - Akimoto, Ginga
AU - Akimov, Andrei
AU - Alberghi, Gian Luigi
AU - Albert, Justin
AU - Albrand, Solveig
AU - Alconada Verzini, Maria Jose
AU - Aleksa, Martin
AU - Aleksandrov, Igor
AU - Alexa, Calin
AU - Alexander, Gideon
AU - Alexandre, Gauthier
AU - Alexopoulos, Theodoros
AU - Alhroob, Muhammad
AU - Alimonti, Gianluca
AU - Alio, Lion
AU - Alison, John
AU - Allbrooke, Benedict
AU - Allison, Lee John
AU - Clark, Philip Jam
AU - Farrington, Sinead
AU - Leonidopoulos, Christos
AU - Martin, Victoria J
AU - Mijović, Liza
AU - Mills, Corrinne
N1 - 21 pages plus author list + cover pages (34 pages total), 9 figues, 8 tables, an addendum added to the published version and available as Eur. Phys. J. C 76 (2016) 642, http://dx.doi.org/10.1140/epjc/s10052-016-4501-2. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/TOPQ-2013-04/
PY - 2014/10/29
Y1 - 2014/10/29
N2 - The inclusive top quark pair (tt¯tt¯) production cross-section σtt¯σtt¯ has been measured in proton–proton collisions at s√=7 TeVs=7 TeV and s√=8 TeVs=8 TeV with the ATLAS experiment at the LHC, using tt¯tt¯ events with an opposite-charge eμeμ pair in the final state. The measurement was performed with the 2011 7 TeV dataset corresponding to an integrated luminosity of 4.6 fb−1fb−1 and the 2012 8 TeV dataset of 20.3 fb−1fb−1. The numbers of events with exactly one and exactly two bb-tagged jets were counted and used to simultaneously determine σtt¯σtt¯ and the efficiency to reconstruct and bb-tag a jet from a top quark decay, thereby minimising the associated systematic uncertainties. The cross-section was measured to be:σtt¯σtt¯=182.9±3.1±4.2±3.6±3.3 pb (s√=7 TeV)and=242.4±1.7±5.5±7.5±4.2 pb (s√=8 TeV),σtt¯=182.9±3.1±4.2±3.6±3.3 pb (s=7 TeV)andσtt¯=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 mpoletmtpole giving a result of mpoletmtpole =172.9+2.5−2.6=172.9−2.6+2.5 GeV. By looking for an excess of tt¯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~1t~1 with masses close to the top quark mass, decaying via t~1→tχ~01t~1→tχ~10 to predominantly right-handed top quarks and a light neutralino χ~01χ~10, the lightest supersymmetric particle. Top squarks with masses between the top quark mass and 177 GeV are excluded at the 95 % confidence level.
AB - The inclusive top quark pair (tt¯tt¯) production cross-section σtt¯σtt¯ has been measured in proton–proton collisions at s√=7 TeVs=7 TeV and s√=8 TeVs=8 TeV with the ATLAS experiment at the LHC, using tt¯tt¯ events with an opposite-charge eμeμ pair in the final state. The measurement was performed with the 2011 7 TeV dataset corresponding to an integrated luminosity of 4.6 fb−1fb−1 and the 2012 8 TeV dataset of 20.3 fb−1fb−1. The numbers of events with exactly one and exactly two bb-tagged jets were counted and used to simultaneously determine σtt¯σtt¯ and the efficiency to reconstruct and bb-tag a jet from a top quark decay, thereby minimising the associated systematic uncertainties. The cross-section was measured to be:σtt¯σtt¯=182.9±3.1±4.2±3.6±3.3 pb (s√=7 TeV)and=242.4±1.7±5.5±7.5±4.2 pb (s√=8 TeV),σtt¯=182.9±3.1±4.2±3.6±3.3 pb (s=7 TeV)andσtt¯=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 mpoletmtpole giving a result of mpoletmtpole =172.9+2.5−2.6=172.9−2.6+2.5 GeV. By looking for an excess of tt¯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~1t~1 with masses close to the top quark mass, decaying via t~1→tχ~01t~1→tχ~10 to predominantly right-handed top quarks and a light neutralino χ~01χ~10, the lightest supersymmetric particle. Top squarks with masses between the top quark mass and 177 GeV are excluded at the 95 % confidence level.
KW - hep-ex
U2 - 10.1140/epjc/s10052-014-3109-7
DO - 10.1140/epjc/s10052-014-3109-7
M3 - Article
SN - 1434-6044
VL - 76
JO - The European Physical Journal C
JF - The European Physical Journal C
IS - 11
M1 - 3109
ER -
