Lepton-Flavor Violating Mediators

TL;DR

This paper introduces a novel lepton-flavor violating mediator model for dark matter interactions, which relaxes experimental bounds and can explain astrophysical gamma-ray excesses, while remaining consistent with flavor physics constraints.

Contribution

It proposes a new framework for dark matter interactions via a light, flavor-violating mediator, and explores its implications for astrophysics, flavor physics, and experimental constraints.

Findings

Model explains Fermi-LAT gamma-ray excess

Compatible with muon g-2 anomaly

Relaxes bounds from terrestrial and cosmic-ray experiments

Abstract

We present a framework where dark matter interacts with the Standard Model through a light, spin-0 mediator that couples chirally to pairs of different-flavor leptons. This flavor violating final state weakens bounds on new physics coupled to leptons from terrestrial experiments and cosmic-ray measurements. As an example, we apply this framework to construct a model for the Fermi-LAT excess of GeV $\gamma$-rays from the galactic center. We comment on the viability of this portal for self-interacting dark matter explanations of small scale structure anomalies and embeddings in flavor models. Models of this type are shown to be compatible with the muon anomalous magnetic moment anomaly. We review current experimental constraints and identify possible future theoretical and experimental directions.