Enhancement of the annihilation of dark matter in a radiative seesaw model

TL;DR

This paper extends a radiative seesaw dark matter model to enhance annihilation rates, successfully explaining cosmic ray positron excesses observed by PAMELA and Fermi-LAT while maintaining consistency with neutrino and dark matter relic data.

Contribution

The paper introduces an extension to the radiative seesaw model that increases dark matter annihilation cross sections without disrupting existing neutrino and dark matter relic constraints.

Findings

Extended model explains PAMELA and Fermi-LAT positron excesses.

Enhanced annihilation cross section consistent with gamma-ray constraints.

Model maintains neutrino mass and dark matter relic abundance features.

Abstract

The radiative seesaw model with an inert doublet has been shown to be attractive from a viewpoint of both neutrino masses and cold dark matter. However, if we apply this model to the explanation of the positron excess in the cosmic ray observed by PAMELA, a huge boost factor is required although it can be automatically explained that no anti-proton excess has been observed there. We consider an extension of the model to enhance the thermally averaged annihilation cross section without changing the features of the model favored by both the neutrino oscillation and the relic abundance of dark matter. It is shown that the data of PAMELA and Fermi-LAT can be well explained in this extended model. Constraints from gamma ray observations are also discussed.