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Title: Augury of darkness: the low-mass dark Z' portal

Dirac fermion dark matter models with heavy Z' mediators are subject to stringent constraints from spin-independent direct searches and from LHC bounds, cornering them to live near the Z' resonance. Such constraints can be relaxed, however, by turning off the vector coupling to Standard Model fermions, thus weakening direct detection bounds, or by resorting to light Z' masses, below the Z pole, to escape heavy resonance searches at the LHC. In this work we investigate both cases, as well as the applicability of our findings to Majorana dark matter. We derive collider bounds for light Z' gauge bosons using the CL S method, spin-dependent scattering limits, as well as the spin-independent scattering rate arising from the evolution of couplings between the energy scale of the mediator mass and the nuclear energy scale, and indirect detection limits. In conclusion, we show that such scenarios are still rather constrained by data, and that near resonance they could accommodate the gamma-ray GeV excess in the Galactic center.
 [1] ;  [2] ;  [3] ;  [4] ;  [2]
  1. Univ. Federal de Sao Paulo, Sao Paulo (Brazil)
  2. Max-Planck-Institut fur Kernphysik, Heidelberg (Germany)
  3. Univ. de Paris-Saclay, Orsay Cedex (France)
  4. Univ. of California, Santa Cruz, CA (United States); Santa Cruz Institute for Particle Physics, Santa Cruz, CA (United States)
Publication Date:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Journal of High Energy Physics (Online)
Additional Journal Information:
Journal Name: Journal of High Energy Physics (Online); Journal Volume: 2017; Journal Issue: 4; Journal ID: ISSN 1029-8479
Springer Berlin
Research Org:
Univ. of California, Santa Cruz, CA (United States)
Sponsoring Org:
Country of Publication:
United States
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; Cosmology of Theories beyond the SM; Beyond Standard Model
OSTI Identifier: