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Title: Diphoton excess through dark mediators

Preliminary ATLAS and CMS results from the first 13 TeV LHC run have encountered an intriguing excess of events in the diphoton channel around the invariant mass of 750 GeV. We investigate a possibility that the current excess is due to a heavy resonance decaying to light metastable states, which in turn give displaced decays to very highly collimated e +e pairs. Such decays may pass the photon selection criteria, and successfully mimic the diphoton events, especially at low counts. We investigate two classes of such models, characterized by the following underlying production and decay chains: gg → S → A'A' → (e +e )(e +e ) and qq¯→ Z' → sa → (e +e ) (e +e ), where at the first step a heavy scalar, S, or vector, Z', resonances are produced that decay to light metastable vectors, A', or (pseudo-)scalars, s and a. Setting the parameters of the models to explain the existing excess, and taking the ATLAS detector geometry into account, we marginalize over the properties of heavy resonances in order to derive the expected lifetimes and couplings of metastable light resonances. In conclusion, we observe that in the case of A', the suggested rangemore » of masses and mixing angles ϵ is within reach of several new-generation intensity frontier experiments.« less
Authors:
 [1] ;  [2] ;  [1] ;  [3]
  1. Univ. of Victoria, Victoria, BC (Canada); Perimeter Institute for Theoretical Physics, Waterloo, ON (Canada)
  2. Univ. of Victoria, Victoria, BC (Canada)
  3. Stony Brook Univ., Stony Brook, NY (United States)
Publication Date:
Grant/Contract Number:
SC0008061
Type:
Accepted Manuscript
Journal Name:
Journal of High Energy Physics (Online)
Additional Journal Information:
Journal Name: Journal of High Energy Physics (Online); Journal Volume: 2016; Journal Issue: 7; Journal ID: ISSN 1029-8479
Publisher:
Springer Berlin
Research Org:
SUNY Stony Brook, Stony Brook, NY (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; Beyond Standard Model; Higgs physics
OSTI Identifier:
1361522