Photonic portal to the sterile world of cold dark matter

TL;DR

This paper proposes a new portal connecting sterile dark matter particles to the Standard Model via weak photon interactions, suggesting a nongravitational link through electromagnetic fields.

Contribution

It introduces a novel photon-mediated portal for sterile dark matter particles, distinct from supersymmetric models, involving weak effective interactions with the electromagnetic field.

Findings

Sterile particles can interact with photons through very weak effective couplings.

A tiny quasi-magnetic correction to the electromagnetic current is predicted.

The model provides a nongravitational link between dark matter and Standard Model fields.

Abstract

We assume that the cold dark matter consists of spin-1/2 and spin-0 particles described by a bispinor field \psi and a scalar field \phi, sterile from all Standard Model charges (in contrast, neutralinos, supersymmetric candidates for cold dark matter, are not sterile from weak Standard Model charges). We propose, however, that such a sterile world can contact with our Standard Model world not only through gravity but also through a portal provided by photons coupled to sterile particles by means of two very weak effective interactions -(f/M^2)\phi F^{\mu\nu}\phi F_{\mu\nu} and -(f'/M^2) (\bar\psi \sigma^{\mu\nu} \psi)\phi F_{\mu\nu}, where M is a very large mass scale and f and f' are dimensionless coupling constants. Thus, in our picture, the electromagnetic field F_{\mu\nu} - as the only Standard Model field - participates in both worlds, providing a nongravitational link between them (other than the popular supersymmetric weak interaction, active in the case of neutralinos). In consequence, there appears a tiny quasi-magnetic correction to the conventional electromagnetic current (described in Appendix A).