Explain DAMPE Results by Dark Matter With Hierarchical Lepton-Specific Yukawa Interactions

TL;DR

This paper proposes a dark matter model with hierarchical lepton-specific Yukawa interactions to explain the DAMPE electron excess at 1.5 TeV, incorporating mechanisms to evade experimental constraints and enhance annihilation signals.

Contribution

It introduces a novel dark matter framework with hierarchical Yukawa couplings and explores enhancement mechanisms to account for DAMPE observations.

Findings

Dark matter annihilation can produce electrons consistent with DAMPE data.

Hierarchical Yukawa couplings suppress unwanted vector boson production.

Resonant and Sommerfeld enhancements relax model constraints.

Abstract

We propose to interpret the DAMPE electron excess at 1.5 TeV through scalar or Dirac fermion dark matter (DM) annihilation with doubly charged scalar mediators that have lepton-specific Yukawa couplings. Hierarchy of such lepton-specific Yukawa couplings is generated through the Froggatt-Nielsen mechanism, so that the dark matter annihilation products can be dominantly electrons. Stringent constraints from LEP2 on intermediate vector boson production can be evaded in our scenarios. In the case of scalar DM, we discuss one scenario with DM annihilating directly to leptons and the other scenario with DM annihilating to scalar mediators followed by their decays. We also discuss the Breit-Wigner resonant enhancement and the Sommerfeld enhancement in case that the s-wave annihilation process is small or helicity suppressed. With both types of enhancement, constraints on the parameters can be relaxed and new ways for model building will be open in explaining the DAMPE results.