Simultaneous measurements of the $t\bar{t}$, $W^{+}{W}^{-}$, and $Z/{\gamma }^{\ast }\to \tau \tau$ production cross-sections in $pp$ collisions at $\sqrt{s}=7$ TeV with the ATLAS detector

Abstract

Simultaneous measurements of the $t\bar{t}$, $W^{+}{W}^{-}$, and $Z/{\gamma }^{\ast }\to \tau \tau$ production cross-sections using an integrated luminosity of $4.6{\mathrm{fb}}^{-1}$ of $pp$ collisions at $\sqrt{s}=7\mathrm{TeV}$ collected by the ATLAS detector at the LHC are presented. Events are selected with two high transverse momentum leptons consisting of an oppositely charged electron and muon pair. The three processes are separated using the distributions of the missing transverse momentum of events with zero and greater than zero jet multiplicities. Measurements of the fiducial cross-section are presented along with results that quantify for the first time the underlying correlations in the predicted and measured cross-sections due to proton parton distribution functions. These results indicate that the correlated NLO predictions for $t\bar{t}$ and $Z/{\gamma }^{\ast }\to \tau \tau$ underestimate the data, while those at NNLO generally describe the data well. The full cross-sections are measured to be $\sigma (t\bar{t})=181.2\pm 2.8_{-9.5}^{+9.7}\pm 3.3\pm 3.3\mathrm{pb}$, $\sigma (W^{+}{W}^{-})=53.3\pm 2.7_{-8.0}^{+7.3}\pm 1.0\pm 0.5\mathrm{pb}$, and $\sigma (Z/{\gamma }^{\ast }\to \tau \tau )=1174\pm 24_{-87}^{+72}\pm 21\pm 9\mathrm{pb}$, where the cited uncertainties are due to statistics, systematic effects, luminosity and the LHC beam energy measurement, respectively. The $W^{+}{W}^{-}$ measurement includes the small contribution from Higgs boson decays, $H\to W^{+}{W}^{-}$.

22 pages plus author list + cover pages (35 pages total), 7 figures, 7 tables, submitted to PRD, All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/TOPQ-2012-05/

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Cited by in corpus (6)

• Differential top-antitop cross-section measurements as a function of observables constructed from final-state particles using pp collisions at $\sqrt{s}=7$ TeV in the ATLAS detector
• Determination of the top-quark mass from hadro-production of single top-quarks
• NNLO PDFs driven by top-quark data
• Top quark physics in the Large Hadron Collider era
• Measurement of the inclusive $t\bar{t}$ production cross section in the lepton+jets channel in $pp$ collisions at $\sqrt{s}$= 7 TeV with the ATLAS detector using support vector machines
• Measurement of the inclusive ttbar cross section in the LHC