Toward (Finally!) Ruling Out Z and Higgs Mediated Dark Matter Models [CL]

http://arxiv.org/abs/1609.09079


In recent years, direct detection, indirect detection, and collider experiments have placed increasingly stringent constraints on particle dark matter, exploring much of the parameter space associated with the WIMP paradigm. In this paper, we focus on the subset of WIMP models in which the dark matter annihilates in the early universe through couplings to either the Standard Model $Z$ or the Standard Model Higgs boson. Considering fermionic, scalar, and vector dark matter candidates within a model-independent context, we find that the overwhelming majority of these dark matter candidates are already ruled out by existing experiments. In the case of $Z$ mediated dark matter, the only scenario that is not already experimentally excluded is that of a fermionic dark matter candidate with an axial coupling and with a mass within a few GeV of the $Z$ resonance ($m_{\rm DM} \simeq m_Z/2$). Several Higgs mediated scenarios are currently viable if the mass of the dark matter is near the Higgs pole ($m_{\rm DM} \simeq m_H/2$). Otherwise, the only scenarios that are not excluded are those in which the dark matter is a scalar (vector) heavier than 400 GeV (1160 GeV) with a Higgs portal coupling, or a fermion with a pseudoscalar (CP violating) coupling to the Standard Model Higgs boson. With the exception of dark matter with a purely pseudoscalar coupling to the Higgs, it is anticipated that planned direct detection experiments will probe the entire range of models considered in this study.

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M. Escudero, A. Berlin, D. Hooper, et. al.
Fri, 30 Sep 16
55/75

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