Measurements of Zγ and Zγγ production in pp collisions at s =8 TeV with the ATLAS detector



Aad, G, Abbott, B, Abdallah, J, Abdinov, O, Abeloos, B, Aben, R, Abolins, M, Abouzeid, OS, Abraham, NL, Abramowicz, H
et al (show 90 more authors) (2016) Measurements of Zγ and Zγγ production in pp collisions at s =8 TeV with the ATLAS detector Physical Review D, 93 (11). ISSN 2470-0010, 2470-0029

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Abstract

The production of Z bosons with one or two isolated high-energy photons is studied using pp collisions at s=8 TeV. The analyses use a data sample with an integrated luminosity of 20.3 fb-1 collected by the ATLAS detector during the 2012 LHC data taking. The Zγ and Zγγ production cross sections are measured with leptonic (e+e-, μ+μ-, νν) decays of the Z boson, in extended fiducial regions defined in terms of the lepton and photon acceptance. They are then compared to cross-section predictions from the Standard Model, where the sources of the photons are radiation off initial-state quarks and radiative Z-boson decay to charged leptons, and from fragmentation of final-state quarks and gluons into photons. The yields of events with photon transverse energy ET>250 GeV from +-γ events and with ET>400 GeV from ννγ events are used to search for anomalous triple gauge-boson couplings ZZγ and Zγγ. The yields of events with diphoton invariant mass mγγ>200 GeV from +-γγ events and with mγγ>300 GeV from ννγγ events are used to search for anomalous quartic gauge-boson couplings ZZγγ and Zγγγ. No deviations from Standard Model predictions are observed and limits are placed on parameters used to describe anomalous triple and quartic gauge-boson couplings.

Item Type: Article
Depositing User: Symplectic Admin
Date Deposited: 14 Mar 2017 10:29
Last Modified: 24 Jun 2026 20:14
DOI: 10.1103/PhysRevD.93.112002
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URI: https://livrepository.liverpool.ac.uk/id/eprint/3006375
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