Measurements of $Z\gamma$ and $Z\gamma\gamma$ production in $pp$ collisions at $\sqrt{s}=$ 8 TeV with the ATLAS detector

G. Aad 1 S. Albrand 2 S. Berlendis 2 C. Camincher 2 J. Collot 2 S. Crépé-Renaudin 2 P.A. Delsart 2 C. Gabaldon 2 M.H. Genest 2 J. Gradin 2 J.Y. Hostachy 2 F. Ledroit-Guillon 2 A. Lleres 2 A. Lucotte 2 F. Malek 2 E. Petit 2 J. Stark 2 B. Trocmé 2 M. Wu 2 G. Rahal 3 Z. Barnovska 4 N. Berger 4 M. Delmastro 4 L. Di Ciaccio 4 S. Elles 4 K. Grevtsov 4 T. Hryn’ova 4 S. Jézéquel 4 I. Koletsou 4 R. Lafaye 4 J. Levêque 4 P. Mastrandea 4 G. Sauvage 4 E. Sauvan 4 O. Simard 4 T. Todorov 4 I. Wingerter-Seez 4 E. Yatsenko 4 D. Boumediene 5 E. Busato 5 D. Calvet 5 S. Calvet 5 A.R. Chomont 5 J. Donini 5 Ph. Gris 5 H. Liao 5 R. Madar 5 D. Pallin 5 S.M. Romano Saez 5 C. Santoni 5 D. Simon 5 F. Vazeille 5 M. Barbero 1 A. Calandri 1 T.P. Calvet 1 Y. Coadou 1 C. Diaconu 1 S. Diglio 1 F. Djama 1 V. Ellajosyula 1 L. Feligioni 1 J. Gao 1 A. Hadef 1 G.D. Hallewell 1 F. Hubaut 1 S.J. Kahn 1 E. B. F. G. Knoops 1 E. Le Guirriec 1 J. Liu 1 K. Liu 1 D. Madaffari 1 K. Mochizuki 1 E. Monnier 1 S. Muanza 1 E. Nagy 1 P. Pralavorio 1 Y. Rodina 1 A. Rozanov 1 M. Talby 1 T. Theveneaux-Pelzer 1 R.E. Ticse Torres 1 S. Tisserant 1 J. Toth 1 F. Touchard 1 L. Vacavant 1 Chen Wang 1 M.K. Ayoub 6 A. Bassalat 6 S. Binet 6 C. Becot 6 C. Bourdarios 6 J.B. de Vivie De Regie 6 D. Delgove 6 L. Duflot 6 M. Escalier 6 L. Fayard 6 D. Fournier 6 E.L. Gkougkousis 6 J.-F. Grivaz 6 T. Guillemin 6 F. Hariri 6 S. Henrot-Versille 6 J. Hrivnac 6 L. Iconomidou-Fayard 6 M. Kado 6 A. Lounis 6 N. Makovec 6 N. Morange 6 C. Nellist 6 P. Petroff 6 L. Poggioli 6 P. Puzo 6 A. Renaud 6 G. Rybkin 6 D. Rousseau 6 A.C. Schaffer 6 L. Serin 6 E. Scifo 6 S. Simion 6 R. Tanaka 6 D. Zerwas 6 Zhongkai Zhang 6 Y. Zhao 6
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.
Type de document :
Article dans une revue
Physical Review D, American Physical Society, 2016, 93, pp.112002. 〈10.1103/PhysRevD.93.112002 〉
Liste complète des métadonnées

http://hal.in2p3.fr/in2p3-01304032
Contributeur : Emmanuelle Vernay <>
Soumis le : mardi 19 avril 2016 - 08:27:10
Dernière modification le : lundi 9 avril 2018 - 12:22:07

Lien texte intégral

Identifiants

Citation

G. Aad, S. Albrand, S. Berlendis, C. Camincher, J. Collot, et al.. Measurements of $Z\gamma$ and $Z\gamma\gamma$ production in $pp$ collisions at $\sqrt{s}=$ 8 TeV with the ATLAS detector. Physical Review D, American Physical Society, 2016, 93, pp.112002. 〈10.1103/PhysRevD.93.112002 〉. 〈in2p3-01304032〉

Partager

Métriques

Consultations de la notice

151