Measurements of Four-Lepton Production at the Z Resonance in pp Collisions at √s=7 and 8 TeV with ATLAS


Measurements of four-lepton (4ℓ, ℓ=e,μ) production cross sections at the Z resonance in pp collisions at the LHC with the ATLAS detector are presented. For dilepton and four-lepton invariant mass regions m_{ℓ⁺ℓ⁻} > 5  GeV and 80 < m_{4ℓ} < 100 GeV, the measured cross sections are 76 ± 18(stat) ± 4(syst) ± 1.4(lumi)  fb and 107 ±9 (stat) ±4(syst) ± 3.0(lumi)  fb at s√=7 and 8 TeV, respectively. By subtracting the nonresonant 4ℓ production contributions and normalizing with Z → μ⁺μ⁻ events, the branching fraction for the Z boson decay to 4ℓ is determined to be (3.20 ± 0.25(stat) ± 0.13(syst))×10⁻⁶, consistent with the standard model prediction.



Leptons (Nuclear physics), Jets (Nuclear physics), Muons, Proton-proton interactions, Branching fractions (Nuclear physics)


CC BY 3.0 (Attribution), ©2014 CERN for the ATLAS Collaboration