Antiproton and Positron Signal Enhancement in Dark Matter Mini-Spikes Scenarios

Abstract

The annihilation of dark matter (DM) in the Galaxy could produce specific imprints on the spectra of antimatter species in Galactic cosmic rays, which could be detected by upcoming experiments such as PAMELA and AMS02. Recent studies show that the presence of substructures can enhance the annihilation signal by a "boost factor" that not only depends on energy, but that is intrinsically a statistical property of the distribution of DM substructures inside the Milky Way. We investigate a scenario in which substructures consist of $\sim 100$ "mini-spikes" around intermediate-mass black holes. Focusing on primary positrons and antiprotons, we find large boost factors, up to a few thousand, that exhibit a large variance at high energy in the case of positrons and at low energy in the case of antiprotons. As a consequence, an estimate of the DM particle mass based on the observed cut-off in the positron spectrum could lead to a substantial underestimate of its actual value.

13 pages, 9 figures, minor changes, version accepted for publication in PRD

References in corpus (5)

• PYTHIA 6.4 Physics and Manual
• PAMELA - A Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics
• Cosmic-ray positron fraction measurement from 1 to 30 GeV with AMS-01
• Collisionally Regenerated Dark Matter Structures in Galactic Nuclei
• Prospects for detecting Dark Matter with neutrino telescopes in Intermediate Mass Black Holes scenarios

Cited by in corpus (18)

• Constraints on WIMP Dark Matter from the High Energy PAMELA $\bar{p}/p$ data
• Gamma-ray and radio tests of the e+e- excess from DM annihilations
• PAMELA data and leptonically decaying dark matter
• Minimal Dark Matter predictions for galactic positrons, anti-protons, photons
• Dark Matter Candidates: A Ten-Point Test
• PAMELA Positron Excess as a Signal from the Hidden Sector
• Neutrino Constraints on the Dark Matter Total Annihilation Cross Section
• Dark Matter Annihilation in Substructures Revised
• Searching for Dark Matter with X-ray Observations of Local Dwarf Galaxies
• Cosmic ray lepton puzzle in the light of cosmological N-body simulations
• Explaining PAMELA and WMAP data through Coannihilations in Extended SUGRA with Collider Implications
• Monochromatic dark neutrinos and boosted dark matter in noble liquid direct detection
• Search for Gamma-rays from Dark Matter annihilations around Intermediate Mass Black Holes with the H.E.S.S. experiment
• Antimatter cosmic rays from dark matter annihilation: First results from an N-body experiment
• Leptophilic-portal Dark Matter in the Light of AMS-02 positron excess
• SZ effects from annihilating dark matter in the Milky Way: smooth halo, subhalos and intermediate-mass-black-holes
• Indirect Searches for Dark Matter with AMS-02
• Anti-proton and positron Cosmic Rays from Dark Matter annihilation around Intermediate Mass Black Holes