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

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 desc...

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Detalles Bibliográficos
Autores principales: Alconada Verzini, María Josefina, Alonso, Francisco, Arduh, Francisco Anuar, Dova, María Teresa, Monticelli, Fernando Gabriel, Wahlberg, Hernán Pablo, The ATLAS Collaboration
Formato: Articulo
Lenguaje:Inglés
Publicado: 2016
Materias:
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/79292
Aporte de:SEDICI (UNLP) de Universidad Nacional de La Plata Ver origen
Descripción
Sumario: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 → γ γ )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.