A testable scenario of WIMPZILLA with Dark Radiation

TL;DR

This paper proposes a scenario where superheavy dark matter, stabilized by a new abelian gauge symmetry, naturally produces dark radiation that can be tested through its effects on the effective number of neutrino species, with potential implications for Higgs decay.

Contribution

It introduces a testable model linking superheavy dark matter stability, dark radiation, and Higgs decay via a new gauge symmetry and scalar interactions.

Findings

Dark radiation contribution from WIMPZILLA decay is estimated.

The model predicts observable effects on the effective number of neutrino species.

Higgs invisible decay could be affected by the scalar portal coupling.

Abstract

As the electromagnetic gauge symmetry makes the electron stable, a new abelian gauge symmetry may be responsible for the stability of superheavy dark matter. The gauge boson associated with the new gauge symmetry naturally plays the role of dark radiation and contributes to the effective number of `neutrino species', which has been recently measured by Planck. We estimate the contribution of dark radiation from the radiative decay of a scalar particle induced by the WIMPZILLA in the loop. The scalar particle may affect the invisible decay of the Higgs boson by the Higgs portal type coupling.