Dipole-interacting Fermionic Dark Matter in positron, antiproton, and gamma-ray channels

TL;DR

This paper explores how dipole-interacting fermionic dark matter could explain positron excesses observed in cosmic rays, predicts gamma-ray signals, and discusses constraints from antiproton data and upcoming experiments.

Contribution

It introduces a model of fermionic dark matter with dipole interactions that accounts for positron excesses and predicts gamma-ray signatures, with analysis of observational constraints.

Findings

Positron excess can be explained with a boost factor of 30-80 for dark matter >100 GeV.

No antiproton excess constrains the model parameters.

Predicted gamma-ray lines near the Galactic center could be detected by future experiments.

Abstract

Cosmic ray signals from dipole-interacting dark matter annihilation are considered in the positron, antiproton and photon channels. The predicted signals in the positron channel could nicely account for the excess of positron fraction from Fermi LAT, PAMELA, HEAT and AMS-01 experiments for the dark matter mass larger than 100 GeV with a boost (enhancement) factor of 30-80. No excess of antiproton over proton ratio at the experiments also gives a severe restriction for this scenario. With the boost factors, the predicted signals from Galactic halo and signals as mono-energetic gamma-ray lines (monochromatic photons) for the region close to the Galactic center are investigated. The gamma-ray excess of recent tentative analyses based on Fermi LAT data and the potential probe of the monochromatic lines at a planned experiment, AMS-02, are also considered.