Collaboration, ATLAS
(2016)
Measurements of $Zγ$ and $Zγγ$ production in $pp$
collisions at $\sqrt{s}=$ 8 TeV with the ATLAS detector.
Phys. Rev. D, 93.
112002-.
Abstract
The production of $Z$ bosons with one or two isolated high-energy photons is studied using $pp$ collisions at $\sqrt{s}$ = 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 $Z\gamma$ and $Z\gamma\gamma$ production cross sections are measured with leptonic ($e^{+}e^{-}$, $\mu^{+}\mu^{-}$, $\nu\bar{\nu}$) 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 $E_T >$ 250 GeV from $\ell^{+}\ell^{-}\gamma$ events and with $E_T >$ 400 GeV from $\nu\bar{\nu}\gamma$ events are used to search for anomalous triple gauge-boson couplings $ZZ\gamma$ and $Z\gamma\gamma$. The yields of events with diphoton invariant mass $m_{\gamma\gamma} >$ 200 GeV from $\ell^{+}\ell^{-}\gamma\gamma$ events and with $m_{\gamma\gamma} > $ 300 GeV from $\nu\bar{\nu}\gamma\gamma$ events are used to search for anomalous quartic gauge-boson couplings $ZZ\gamma\gamma$ and $Z\gamma\gamma\gamma$. 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 |
|---|---|
| Additional Information: | 41 pages plus author list + cover pages (59 pages total), 17 figures, 13 tables, submitted to Physical Review D, All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2014-01/ |
| Uncontrolled Keywords: | hep-ex, hep-ex |
| Divisions: | Faculty of Science and Engineering > School of Physical Sciences |
| Depositing User: | Symplectic Admin |
| Date Deposited: | 16 Feb 2024 09:07 |
| Last Modified: | 16 Feb 2024 09:10 |
| Open Access URL: | https://journals.aps.org/prd/abstract/10.1103/Phys... |
| Related URLs: | |
| URI: | https://livrepository.liverpool.ac.uk/id/eprint/3178706 |
Share
Share
