Metastable Conformal Dark Matter

TL;DR

This paper proposes a naturally arising metastable dark matter candidate from conformal transformations between Einstein and Jordan metrics, which interacts mainly with the Higgs field and produces observable monochromatic signals upon decay.

Contribution

It introduces a new metastable dark matter model derived from conformal transformations, explaining its long lifetime and potential observational signatures.

Findings

Dark matter couples primarily to the Higgs energy momentum tensor.

Dark matter can have a mass below 1 MeV with a lifetime exceeding the universe's age.

Decay signatures include monochromatic neutrino and gamma-ray lines.

Abstract

We show that a metastable dark matter candidate arises naturally from the conformal transformation between the Einstein metric, where gravitons are normalised states, and the Jordan metric dictating the coupling between gravity and matter. Despite being secluded from the Standard Model by a large scale above which the Jordan metric shows modifications to the Einstein frame metric, dark matter couples to the energy momentum tensor of the Higgs field in the primordial plasma primarily. This allows for the production of dark matter in a sufficient amount which complies with observations. The seclusion of dark matter makes it long-lived for masses $\lesssim 1$ MeV, with a lifetime much above the age of the Universe and the present experimental limits. Such a dark matter scenario has clear monochromatic signatures generated by the decay of the dark matter candidate into neutrino and/or $\gamma-$rays.