Portal Connecting Dark Photons and Axions

TL;DR

This paper introduces a novel portal connecting dark photons and axions, expanding the theoretical framework for hidden sector particles and suggesting new avenues for experimental searches.

Contribution

It proposes a new dark axion portal coupling, distinct from existing portals, with a simple model demonstrating its realization and potential phenomenological implications.

Findings

Introduces the dark axion portal as a new coupling mechanism.

Provides a simple model realizing the dark axion portal.

Discusses rich phenomenology arising from this new portal.

Abstract

The dark photon and the axion (or axion-like particle) are popular light particles of the hidden sector. Each of them has been actively searched for through the couplings called the vector portal and the axion portal. We introduce a new portal connecting the dark photon and the axion (axion--photon--dark photon, axion--dark photon--dark photon), which emerges in the presence of the two particles. This dark axion portal is genuinely new couplings, not just from a product of the vector portal and the axion portal, because of the internal structure of these couplings. We present a simple model that realizes the dark axion portal and discuss why it warrants a rich phenomenology.