Leptophilic Dark Matter

TL;DR

This work presents a minimal leptophilic dark matter model built around a broken $U(1)_{DS}$ gauge symmetry, where the DM particle $\chi$ annihilates predominantly into light gauge bosons $U$ that subsequently decay to leptons, thereby explaining the PAMELA/ATIC electron/positron excesses while remaining consistent with existing constraints. A Sommerfeld enhancement from a light mediator allows the annihilation rate to reach observational levels, and the couplings to leptons are arranged to evade hadronic final states. Depending on the mediator mass, the same framework can accommodate DAMA via DM–electron scattering or explain leptonic signals without contradicting CDMS, with additional predictions for neutrino signals and potential lepton-jet signatures in UV completions. The model therefore provides a cohesive leptophilic DM scenario with testable implications for indirect detection, direct detection, neutrinos, and collider phenomenology.

Abstract

We describe a simple model of Dark Matter, which explains the PAMELA/ATIC excesses while being consistent with all present constraints. The DAMA annual modulation signal can also be explained for some values of the parameters. The model consists of a Dark Sector containing a weakly coupled broken U(1) gauge symmetry, under which only the Dark Matter state and the leptons are charged.

Figures (1)

• Figure 1: Contour plot of the cross section boost factor as a function of the Dark Matter mass, $M_\chi$, and the $U$-boson mass, $M_U$. The contours from light to dark grey correspond to enhancements of less than $10,\, 50,\,100,\, 150,\, 200$ while white corresponds to more than $200$, and we have taken $v=10^{-3}$ and $g_\chi=0.5$.