Superheavy Dark Matter in Light of Dark Radiation

TL;DR

This paper introduces a new gauge symmetry for superheavy dark matter stability, linking it to dark radiation and potential signals at the LHC, offering a novel approach to dark matter and dark radiation interplay.

Contribution

It proposes a new Abelian gauge symmetry for superheavy dark matter stability and explores its implications for dark radiation and collider signatures.

Findings

Dark radiation contribution from superheavy dark matter decay

Potential detection via invisible Higgs decays at LHC

Consistency with current cosmological measurements

Abstract

Superheavy dark matter can satisfy the observed dark matter abundance if the stability condition is fulfilled. Here, we propose a new Abelian gauge symmetry ${\rm U(1)}_H$ for the stability of superheavy dark matter as the electromagnetic gauge symmetry to the electron. The new gauge boson associated with ${\rm U(1)}_H$ contributes to the effective number of relativistic degrees of freedom in the universe as dark radiation, which has been recently measured by several experiments, e.g., PLANCK. We calculate the contribution to dark radiation from the decay of a scalar particle via the superheavy dark matter in the loop. Interestingly enough, this scenario will be probed by a future LHC run in the invisible decay signatures of the Higgs boson.