Scalar dark matter, Type II Seesaw and the DAMPE cosmic ray $e^+ + e^-$ excess

TL;DR

This paper proposes a minimal model with scalar dark matter and type II seesaw to explain the DAMPE cosmic ray excess at 1.4 TeV, linking it to neutrino mass hierarchy and cosmic ray observations.

Contribution

It introduces a novel minimal framework combining scalar dark matter and type II seesaw to account for the DAMPE excess and its relation to neutrino oscillation data.

Findings

The model explains the 1.4 TeV CRE excess via dark matter annihilation.

It predicts an inverted hierarchy pattern for neutrino masses.

Constraints from Fermi-LAT observations support the model's parameter space.

Abstract

The DArk Matter Particle Explorer (DAMPE) has reported a measurement of the flux of high energy cosmic ray electrons plus positrons (CREs) in the energy range between $25$ GeV and $4.6$ TeV. With unprecedented high energy resolution, the DAMPE data exhibit an excess of the CREs flux at an energy of around $1.4$ TeV. In this letter, we discuss how the observed excess can be understood in a minimal framework where the Standard Model (SM) is supplemented by a stable SM singlet scalar as dark matter (DM) and type II seesaw for generating the neutrino mass matrix. In our framework, a pair of DM particles annihilates into a pair of the SM SU(2) triplet scalars ($\Delta$s) in type II seesaw, and the subsequent $\Delta$ decays create the primary source of the excessive CREs around $1.4$ TeV. The lepton flavor structure of the primary source of CREs has a direct relationship with the neutrino oscillation data. We find that the DM interpretation of the DAMPE excess determines the pattern of neutrino mass spectrum to be the inverted hierarchy type, taking into account the constraints from the Fermi-LAT observations of dwarf spheroidal galaxies.