Allbrooke, B M M, Asquith, L, Cerri, A, Chavez Barajas, C A, De Santo, A, Salvatore, F, Santoyo Castillo, I, Suruliz, K, Sutton, M R, Vivarelli, I and The ATLAS Collaboration, (2016) Search for new phenomena in events with at least three photons collected in pp collisions at √s = 8 TeV with the ATLAS detector. European Physical Journal C: Particles and Fields, 76 (4). p. 210. ISSN 1434-6044

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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 < 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.

Item Type:	Article
Schools and Departments:	School of Mathematical and Physical Sciences > Physics and Astronomy
Research Centres and Groups:	Experimental Particle Physics Research Group
Subjects:	Q Science > QC Physics
Depositing User:	Richard Chambers
Date Deposited:	15 Feb 2017 09:20
Last Modified:	07 Mar 2017 11:46
URI:	http://srodev.sussex.ac.uk/id/eprint/66753

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