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.

Aad, G., Abbott, B., Abdallah, J., Abdinov, O., Abeloos, B., Aben, R., et al. (2016). Measurements of Zγ and Zγγ production in pp collisions at s =8 TeV with the ATLAS detector. PHYSICAL REVIEW D, 93(11), 1-59 [10.1103/PhysRevD.93.112002].

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

ALBERGHI, GIAN LUIGI;BELLAGAMBA, LORENZO;BIONDI, SILVIA;BOSCHERINI, DAVIDE;BRUNI, ALESSIA;BRUNI, GRAZIANO;DE CASTRO, STEFANO;FABBRI, FEDERICA;FABBRI, LAURA;FRANCHINI, MATTEO;GABRIELLI, ALESSANDRO;GIACOBBE, BENEDETTO;LASAGNI MANGHI, FEDERICO;MASSA, LORENZO;MENGARELLI, ALBERTO;POLINI, ALESSANDRO;RINALDI, LORENZO;ROMANO, MARINO;SBARRA, CARLA;SEMPRINI CESARI, NICOLA;SIOLI, MAXIMILIANO;SPIGHI, ROBERTO;UCCHIELLI, GIULIA;VALENTINETTI, SARA;VILLA, MAURO;VITTORI, CAMILLA;I. Vivarelli;ZOCCOLI, ANTONIO;
2016

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.
2016
Aad, G., Abbott, B., Abdallah, J., Abdinov, O., Abeloos, B., Aben, R., et al. (2016). Measurements of Zγ and Zγγ production in pp collisions at s =8 TeV with the ATLAS detector. PHYSICAL REVIEW D, 93(11), 1-59 [10.1103/PhysRevD.93.112002].
Aad, G.; Abbott, B.; Abdallah, J.; Abdinov, O.; Abeloos, B.; Aben, R.; Abolins, M.; Abouzeid, O.  . S.; Abraham, N.  . L.; Abramowicz, H.; Abreu, H.; ...espandi
File in questo prodotto:
Eventuali allegati, non sono esposti

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/589104
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 82
  • ???jsp.display-item.citation.isi??? 27
social impact