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

0465724 - FZÚ 2017 RIV US eng J - Článek v odborném periodiku
Aad, G. - Abbott, B. - Abdallah, J. - Chudoba, Jiří - Havránek, Miroslav - Hejbal, Jiří - Jakoubek, Tomáš - Kepka, Oldřich - Kupčo, Alexander - Kůs, Vlastimil - Lokajíček, Miloš - Lysák, Roman - Marčišovský, Michal - Mikeštíková, Marcela - Němeček, Stanislav - Penc, Ondřej - Šícho, Petr - Staroba, Pavel - Svatoš, Michal - Taševský, Marek - Vrba, Václav … celkem 2860 autorů
Measurements of Zγ and Zγγ production in pp collisions at √s = 8 TeV with the ATLAS detector.
Physical Review D. Roč. 93, č. 11 (2016), 1-41, č. článku 112002. ISSN 2470-0010. E-ISSN 2470-0029
Institucionální podpora: RVO:68378271
Klíčová slova: photon * associated production * Z0 * leptonic decay * ATLAS * fragmentation * CERN LHC Coll
Kód oboru RIV: BF - Elementární částice a fyzika vys. energií
Impakt faktor: 4.557, rok: 2016

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 ℓ+ℓ-γ events and with ET>400  GeV from νν¯γ 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 ℓ+ℓ-γγ events and with mγγ>300  GeV from νν¯γγ 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.


Trvalý link: http://hdl.handle.net/11104/0264170