Dark Matter through the Axion Portal

TL;DR

This paper proposes a supersymmetric model where TeV-scale dark matter annihilates into an axion-like particle, explaining cosmic positron excesses while avoiding anti-proton and gamma-ray signals, with specific axion mass predictions.

Contribution

It introduces a novel supersymmetric framework linking dark matter annihilation to an axion portal, consistent with cosmic ray observations.

Findings

Axion mass estimated between 360-800 MeV.

Model predicts muon decay channels for the axion.

Consistent with positron excess without anti-proton or gamma-ray excess.

Abstract

Motivated by the galactic positron excess seen by PAMELA and ATIC/PPB-BETS, we propose that dark matter is a TeV-scale particle that annihilates into a pseudoscalar "axion." The positron excess and the absence of an anti-proton or gamma ray excess constrain the axion mass and branching ratios. In the simplest realization, the axion is associated with a Peccei-Quinn symmetry, in which case it has a mass around 360-800 MeV and decays into muons. We present a simple and predictive supersymmetric model implementing this scenario, where both the Higgsino and dark matter obtain masses from the same source of TeV-scale spontaneous symmetry breaking.