Complementarity of DM Searches in a Consistent Simplified Model: the Case of Z'

TL;DR

This paper investigates the combined constraints from various detection methods on fermionic Majorana dark matter interacting via a Z' mediator, highlighting the dominant search channels depending on dark matter mass.

Contribution

It provides a detailed analysis of the complementarity between direct, indirect, and collider searches for Z'-mediated dark matter, including a corrected neutrino spectrum analysis.

Findings

Indirect detection sets the strongest bounds for heavy dark matter.

IceCube constraints are generally stronger than direct detection.

LHC constraints dominate for lighter dark matter masses.

Abstract

We analyze the constraints from direct and indirect detection on fermionic Majorana Dark Matter (DM). Because the interaction with the Standard Model (SM) particles is spin-dependent, a priori the constraints that one gets from neutrino telescopes, the LHC, direct and indirect detection experiments are comparable. We study the complementarity of these searches in a particular example, in which a heavy $Z'$ mediates the interactions between the SM and the DM. We find that for heavy dark matter indirect detection provides the strongest bounds on this scenario, while IceCube bounds are typically stronger than those from direct detection. The LHC constraints are dominant for smaller dark matter masses. These light masses are less motivated by thermal relic abundance considerations. We show that the dominant annihilation channels of the light DM in the Sun and the Galactic Center are either $b\bar b$ or $t\bar t$, while the heavy DM annihilation is completely dominated by $Zh$ channel. The latter produces a hard neutrino spectrum which has not been previously analyzed. We study the neutrino spectrum yielded by DM and recast IceCube constraints to allow proper comparison with constraints from direct and indirect detection experiments and LHC exclusions. Note that the original version of the paper contains an important error: the contribution of the $Z$-mediated processes was overlooked. This changes some of the results of the paper. For the details and the correct results please see the erratum attached to this file as an appendix.