The Dark Matter Constraints on the Left-Right Symmetric Model with Z_2 Symmetry

TL;DR

This paper explores dark matter constraints within a Left-Right symmetric model with Z_2 symmetry, identifying stable WIMPs as potential dark matter candidates but facing significant detection and relic abundance challenges.

Contribution

It introduces a scenario solving the VEV seesaw problem with Z_2 symmetry and analyzes the viability of stable WIMPs as dark matter candidates in this framework.

Findings

WIMP-nucleon cross section exceeds experimental bounds by 3-5 orders of magnitude.

Relic density of stable particles must be highly suppressed.

Only under MOND assumptions can WIMPs serve as viable cold dark matter candidates.

Abstract

In the framework of Left-Right symmetric model, we investigate an interesting scenario, in which the so-called VEV seesaw problem can be naturally solved with Z_2 symmetry. In such a scenario, we find a pair of stable weakly interacting massive particles (WIMPs), which may be the cold dark matter candidates. However, the WIMP-nucleon cross section is 3-5 orders of magnitude above the present upper bounds from the direct dark matter detection experiments for $m \sim 10^2-10^4 $ GeV. As a result, the relic number density of two stable particles has to be strongly suppressed to a very small level. Nevertheless, our analysis shows that this scenario can't provide very large annihilation cross sections so as to give the desired relic abundance except for the resonance case. Only for the case if the rotation curves of disk galaxies are explained by the Modified Newtonian Dynamics (MOND), the stable WIMPs could be as the candidates of cold dark matter.