Implications of the dark axion portal for the muon g-2, B-factories, fixed target neutrino experiments and beam dumps

TL;DR

This paper explores the dark axion portal, a new connection between the standard model and dark sector involving dark photons and axions, analyzing its implications for muon g-2, B-factories, neutrino experiments, and beam dumps, with a focus on Belle-II.

Contribution

It introduces the dark axion portal as a novel detection channel and provides model-independent constraints and sensitivities for experimental tests, especially at Belle-II.

Findings

Constraints on axion-photon-dark photon coupling derived

Belle-II sensitivity to the dark axion portal analyzed

Implications for muon g-2 and neutrino experiments discussed

Abstract

The dark axion portal is a recently introduced portal between the standard model and the dark sector. It connects both the dark photon and the axion (or axion-like particle) to the photon simultaneously through an anomaly triangle. While the vector portal and the axion portal have been popular venues to search for the dark photon and axion, respectively, the new portal provides new detection channels if they coexist. The dark axion portal is not a result of the simple combination of the two portals, and its value is not determined by the other portal values; it should be tested independently. In this paper, we discuss implications of the new portal for the leptonic g-2, B-factories, fixed target neutrino experiments, and beam dumps. We provide the model-independent constraints on the axion-photon-dark photon coupling and discuss the sensitivities of the recently activated Belle-II experiment, which will play an important role in testing the new portal.