Radiative Seesaw Model and DAMPE Excess from Leptophilic Gauge Symmetry

TL;DR

This paper introduces an anomaly-free radiative seesaw model with a leptophilic gauge symmetry that explains the DAMPE excess through a stable Dirac fermion dark matter candidate, consistent with experimental constraints.

Contribution

It proposes a novel leptophilic $U(1)_X$ gauge symmetry model with irrational charges, generating neutrino masses and providing a dark matter candidate explaining DAMPE excess.

Findings

Dark Dirac fermion explains DAMPE excess

Model satisfies relic density and detection constraints

Residual $Z_2$ symmetry stabilizes dark matter

Abstract

In the light of the $e^{+}+e^{-}$ excess observed by DAMPE experiment, we propose an anomaly-free radiative seesaw model with an alternative leptophilic $U(1)_X$ gauge symmetry. In the model, only right-handed leptons are charged under $U(1)_X$ symmetry. The tiny Dirac neutrino masses are generated at one-loop level and charged leptons acquire masses though the type-I seesaw-like mechanism with heavy intermediate fermions. In order to cancel the anomaly, irrational $U(1)_{X}$ charge numbers are assigned to some new particles. After the spontaneous breaking of $U(1)_{X}$ symmetry, the dark $Z_{2}$ symmetry could appear as a residual symmetry such that the stability of inert particles with irrational charge numbers are guaranteed, naturally leading to stable DM candidates. We show that the Dirac fermion DM contained in the model can explain the DAMPE excess. Meanwhile, experimental constraints from DM relic density, direct detection, LEP and anomalous magnetic moments are satisfied.