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

Mullier, Geoffrey; Haug, Sigve; Weber, Michael; Meloni, Federico; Cervelli, Alberto; Beck, Hans Peter; Stucci, Stefania; Ereditato, Antonio (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) EDP Sciences 10.1140/epjc/s10052-016-4034-8

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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 <10⁻³ σSM for 10 GeV < ma < 62 GeV. Limits are also presented for Higgs boson-like scalars (H ) for m H >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:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Physics Institute > Laboratory for High Energy Physics (LHEP)

UniBE Contributor:

Haug, Sigve; Weber, Michael and Beck, Hans Peter

Subjects:

500 Science > 530 Physics
500 Science > 510 Mathematics

ISSN:

1434-6044

Publisher:

EDP Sciences

Language:

English

Submitter:

Annette Krebs-Wegenast

Date Deposited:

16 Aug 2017 11:05

Last Modified:

20 Aug 2017 02:18

Publisher DOI:

10.1140/epjc/s10052-016-4034-8

Additional Information:

Kollaboration - Es sind nur die Berner Autoren namentlich erwähnt.

BORIS DOI:

10.7892/boris.100021

URI:

https://boris.unibe.ch/id/eprint/100021

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