Results of a search for new phenomena in events with at least three photons are reported. Data from proton–proton collisions at a centre-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 20.3 fb−1, were collected with the ATLAS detector at the LHC. The observed data are well described by the Standard Model. Limits at the 95 % confidence level on new phenomena are presented based on the rate of events in an inclusive signal region and a restricted signal region targeting the rare decay Z→3γ, as well as di-photon and tri-photon resonance searches. For a Standard Model Higgs boson decaying to four photons via a pair of intermediate pseudoscalar particles (a), limits are found to be σ× BR (h→aa)× BR (a→γγ)2<10−3σSM for 10 GeV <ma< 62 GeV. Limits are also presented for Higgs boson-like scalars (H) for mH> 125 GeV, and for a Z′ decaying to three photons via Z′→a+γ→3γ. Additionally, the observed limit on the branching ratio of the Z boson decay to three photons is found to be BR(Z→3γ)<2.2×10−6, a result five times stronger than the previous result from LEP.

Search for new phenomena in events with at least three photons collected in $pp$ collisions at $\sqrts$ = 8 TeV with the ATLAS detector / Aad, G., Abbott, B., Abdallah, J., Khalek, S.A., Abdinov, O., Aben, R., Abi, B., Abolins, M., Abouzeid, O.S., Abramowicz, H., Abreu, H., Abreu, R., Abulaiti, Y., Acharya, B.S., Adamczyk, L., Adams, D.L., Adelman, J., Adomeit, S., Adye, T., Agatonovic Jovin, T., et al.. - In: THE EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS. - ISSN 1434-6044. - STAMPA. - C76:4(2016). [10.1140/epjc/s10052-016-4034-8]

Search for new phenomena in events with at least three photons collected in $pp$ collisions at $\sqrts$ = 8 TeV with the ATLAS detector

Artoni, G.;BAGNAIA, Paolo;BINI, Cesare;DE CECCO, Sandro;DI DOMENICO, Antonio;GAUZZI, Paolo;GENTILE, Simonetta;GIAGU, Stefano;Kado, M.;LACAVA, Francesco;LUCI, Claudio;MESSINA, Andrea;Policicchio, A.;
2016

Abstract

Results of a search for new phenomena in events with at least three photons are reported. Data from proton–proton collisions at a centre-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 20.3 fb−1, were collected with the ATLAS detector at the LHC. The observed data are well described by the Standard Model. Limits at the 95 % confidence level on new phenomena are presented based on the rate of events in an inclusive signal region and a restricted signal region targeting the rare decay Z→3γ, as well as di-photon and tri-photon resonance searches. For a Standard Model Higgs boson decaying to four photons via a pair of intermediate pseudoscalar particles (a), limits are found to be σ× BR (h→aa)× BR (a→γγ)2<10−3σSM for 10 GeV 125 GeV, and for a Z′ decaying to three photons via Z′→a+γ→3γ. Additionally, the observed limit on the branching ratio of the Z boson decay to three photons is found to be BR(Z→3γ)<2.2×10−6, a result five times stronger than the previous result from LEP.
2016
01 Pubblicazione su rivista::01a Articolo in rivista
Search for new phenomena in events with at least three photons collected in $pp$ collisions at $\sqrts$ = 8 TeV with the ATLAS detector / Aad, G., Abbott, B., Abdallah, J., Khalek, S.A., Abdinov, O., Aben, R., Abi, B., Abolins, M., Abouzeid, O.S., Abramowicz, H., Abreu, H., Abreu, R., Abulaiti, Y., Acharya, B.S., Adamczyk, L., Adams, D.L., Adelman, J., Adomeit, S., Adye, T., Agatonovic Jovin, T., et al.. - In: THE EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS. - ISSN 1434-6044. - STAMPA. - C76:4(2016). [10.1140/epjc/s10052-016-4034-8]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/948230
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