Diphoton excess through dark mediators

Chen, Chien -Yi; Lefebvre, Michel; Pospelov, Maxim; Zhong, Yi -Ming

doi:10.1007/JHEP07(2016)063

Title: Diphoton excess through dark mediators

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Abstract

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 range of masses and mixing angles ϵ is within reach ofmore »« less

Authors:

Chen, Chien -Yi ^[1]; Lefebvre, Michel ^[2]; Pospelov, Maxim ^[1]; Zhong, Yi -Ming ^[3]

Univ. of Victoria, Victoria, BC (Canada); Perimeter Institute for Theoretical Physics, Waterloo, ON (Canada)
Univ. of Victoria, Victoria, BC (Canada)
Stony Brook Univ., Stony Brook, NY (United States)

Publication Date:: Tue Jul 12 00:00:00 EDT 2016

Research Org.:: SUNY Stony Brook, Stony Brook, NY (United States)

Sponsoring Org.:: USDOE Office of Science (SC)

OSTI Identifier:: 1361522

Grant/Contract Number:: SC0008061

Resource 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

Country of Publication:: United States

Language:: English

Subject:: 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; Beyond Standard Model; Higgs physics

Citation Formats


                    Chen, Chien -Yi, Lefebvre, Michel, Pospelov, Maxim, and Zhong, Yi -Ming. Diphoton excess through dark mediators.  United States: N. p., 2016. 
Web.  doi:10.1007/JHEP07(2016)063.

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                    Chen, Chien -Yi, Lefebvre, Michel, Pospelov, Maxim, & Zhong, Yi -Ming. Diphoton excess through dark mediators.  United States.  https://doi.org/10.1007/JHEP07(2016)063

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                    Chen, Chien -Yi, Lefebvre, Michel, Pospelov, Maxim, and Zhong, Yi -Ming. Tue .  
"Diphoton excess through dark mediators".  United States.  https://doi.org/10.1007/JHEP07(2016)063.  https://www.osti.gov/servlets/purl/1361522.

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@article{osti_1361522,

  title        = {Diphoton excess through dark mediators},

  author       = {Chen, Chien -Yi and Lefebvre, Michel and Pospelov, Maxim and Zhong, Yi -Ming},

  abstractNote = {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 range of masses and mixing angles ϵ is within reach of several new-generation intensity frontier experiments.},

  doi          = {10.1007/JHEP07(2016)063},

  journal      = {Journal of High Energy Physics (Online)},

  number       = 7,

  volume       = 2016,

  place        = {United States},

  year         = {Tue Jul 12 00:00:00 EDT 2016},

  month        = {Tue Jul 12 00:00:00 EDT 2016}

}

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