Augury of darkness: the low-mass dark Z′ portal

• Published in: The journal of high energy physics Vol. 2017; no. 4; pp. 1 - 23
• Main Authors: Alves, Alexandre, Arcadi, Giorgio, Mambrini, Yann, Profumo, Stefano, Queiroz, Farinaldo S.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.04.2017; Springer Nature B.V; Springer; Springer Berlin; SpringerOpen
• Subjects: Astrophysics; Beyond Standard Model; Bosons; Classical and Quantum Gravitation; Cosmology of Theories beyond the SM; Couplings; Dark matter; Elementary Particles; Fermions; Gamma rays; High energy physics; High Energy Physics - Phenomenology; Large Hadron Collider; Nuclear electric power generation; Nuclear engineering; Physics; Physics and Astronomy; PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; Quantum Field Theories; Quantum Field Theory; Quantum Physics; Regular Article - Theoretical Physics; Relativity Theory; Scattering; Searching; String Theory; Beyond Standard Model; Cosmology of Theories beyond the SM; new physics; fermion: new particle; gamma ray: cosmic radiation; dark matter: direct detection; Z': mediation; cosmic radiation: spectrum; WIMP: dark matter; WIMP nucleon: scattering; Z': mass; fermion: dark matter; dark matter: scattering; dark matter: mediation; coupling: vector; WIMP nucleon: cross section; fermion: Dirac; Z': coupling; cross section: spin: dependence
• ISSN: 1029-8479; 1126-6708; 1029-8479
• DOI: 10.1007/JHEP04(2017)164

A bstract 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. 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.