Light dark matter versus astrophysical constraints

TL;DR

This paper explores a model of light dark matter that evades astrophysical constraints through annihilation into invisible states, proposing testable predictions involving new gauge bosons and a fourth quark generation.

Contribution

It introduces a quasi-Dirac dark matter model with two U(1) gauge bosons, providing a novel way to evade astrophysical constraints on light dark matter.

Findings

Model predicts detection of light gauge bosons in upcoming experiments.

Annihilation into dark neutrinos allows evasion of astrophysical constraints.

Presence of a fourth quark generation affects Higgs production at colliders.

Abstract

Hints of direct dark matter detection coming from the DAMA, CoGeNT experiments point toward light dark matter with isospin-violating and possibly inelastic couplings. However an array of astrophysical constraints are rapidly closing the window on light dark matter. We point out that if the relic density is determined by annihilation into invisible states, these constraints can be evaded. As an example we present a model of quasi-Dirac dark matter, interacting via two U(1) gauge bosons, one of which couples to baryon number and the other which kinetically mixes with the photon. Annihilation is primarily into "dark neutrinos" that do not mix with the SM, but which could provide a small component of dark radiation. The model could soon be tested by several experiments searching for such light gauge bosons, and we predict that both could be detected. The model also requires a fourth generation of quarks, whose existence might increase the production cross section of Higgs bosons at the Tevatron and LHC.