The four-lepton (4l, l = e, mu) production cross section is measured in the mass range from 80 to 1000GeV using 20.3 fb(-1)of data in pp collisions at root s = 8 TeV collected with the ATLAS detector at the LHC. The 4l events are produced in the decays of resonant Zand Higgs bosons and the nonresonant ZZcontinuum originating from q (q) over bar, gg, and qg initial states. A total of 476 signal candidate events are observed with a background expectation of 26.2 +/- 3.6 events, enabling the measurement of the integrated cross section and the differential cross section as a function of the invariant mass and transverse momentum of the four-lepton system. In the mass range above 180GeV, assuming the theoretical constraint on the q (q) over bar production cross section calculated with perturbative NNLO QCD and NLO electroweak corrections, the signal strength of the gluon-fusion component relative to its leading-order prediction is determined to be mu(gg) = 2.4 +/- 1.0(stat.) +/- 0.5(syst.) +/- 0.8(theory). (C) 2015 CERN for the benefit of the ATLAS Collaboration. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Measurements of four-lepton production in pp collisions at √s = 8 TeV with the ATLAS detector

CONTA, CLAUDIO;DONDERO, PAOLO;FRATERNALI, MARCO;INTROZZI, GIANLUCA;LIVAN, MICHELE;NEGRI, ANDREA;REBUZZI, DANIELA MARCELLA;RIMOLDI, ADELE;
2016-01-01

Abstract

The four-lepton (4l, l = e, mu) production cross section is measured in the mass range from 80 to 1000GeV using 20.3 fb(-1)of data in pp collisions at root s = 8 TeV collected with the ATLAS detector at the LHC. The 4l events are produced in the decays of resonant Zand Higgs bosons and the nonresonant ZZcontinuum originating from q (q) over bar, gg, and qg initial states. A total of 476 signal candidate events are observed with a background expectation of 26.2 +/- 3.6 events, enabling the measurement of the integrated cross section and the differential cross section as a function of the invariant mass and transverse momentum of the four-lepton system. In the mass range above 180GeV, assuming the theoretical constraint on the q (q) over bar production cross section calculated with perturbative NNLO QCD and NLO electroweak corrections, the signal strength of the gluon-fusion component relative to its leading-order prediction is determined to be mu(gg) = 2.4 +/- 1.0(stat.) +/- 0.5(syst.) +/- 0.8(theory). (C) 2015 CERN for the benefit of the ATLAS Collaboration. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11571/1175803
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