Protohalo Constraints to the Resonant Annihilation of Dark Matter

Abstract

It has recently been argued that the PAMELA, ATIC and PPB-BETS data showing an anomalous excess of high-energy cosmic ray positrons and electrons might be explained by dark matter annihilating in the Galactic halo with a cross section resonantly enhanced compared to its value in the primeval plasma. We find that with a very large annihilation cross section the flash of energetic photons and electron-positron pairs expected from dark-matter annihilation in the first protohalos that form at redshift z~40 is likely substantial and observable. As a consequence, bounds on the allowed energy injection into the primordial gas and the energy density of the diffuse gamma-ray background give rise to limits on the low-velocity dark matter cross section that can be difficult to reconcile with this interpretation of the PAMELA, ATIC and PPB-BETS results.

arXiv comment5 pages, 4 figures; References added, estimates refined and discussion extended

References in corpus (17)

• Observation of an anomalous positron abundance in the cosmic radiation
• Halo Models of Large Scale Structure
• A Theory of Dark Matter
• Measurement of the Cosmic Ray e+ plus e- spectrum from 20 GeV to 1 TeV with the Fermi Large Area Telescope
• DarkSUSY: Computing Supersymmetric Dark Matter Properties Numerically
• EGRET Observations of the Extragalactic Gamma Ray Emission
• Particle decays during the cosmic dark ages
• What mass are the smallest protohalos?
• Breit-Wigner Enhancement of Dark Matter Annihilation
• PAMELA Positron Excess as a Signal from the Hidden Sector
• Contraints on radiative dark-matter decay from the cosmic microwave background
• Dark Matter Signals from Cascade Annihilations
• Galactic Substructure and Direct Detection of Dark Matter
• Extragalactic Inverse Compton Light from Dark Matter Annihilation and the Pamela Positron Excess
• Early Annihilation and Diffuse Backgrounds in 1/v WIMP models
• Gamma-Ray Background from Neutralino Annihilation in the First Cosmological Objects
• Nambu-Goldstone Dark Matter and Cosmic Ray Electron and Positron Excess

Cited by in corpus (14)

• Dark Matter Interpretations of the Electron/Positron Excesses after FERMI
• The nature of the Diffuse Gamma-Ray Background
• Robust implications on Dark Matter from the first FERMI sky gamma map
• Constraints on Decaying Dark Matter from Fermi Observations of Nearby Galaxies and Clusters
• Multicomponent Dark Matter in Supersymmetric Hidden Sector Extensions
• The Contribution Of Inverse Compton Scattering To The Diffuse Extragalactic Gamma-Ray Background From Annihilating Dark Matter
• Strong Optimized Conservative Fermi-LAT Constraints on Dark Matter Models from the Inclusive Photon Spectrum
• Late Kinetic Decoupling of Light Magnetic Dipole Dark Matter
• Cosmic Ray Spectra in Nambu-Goldstone Dark Matter Models
• Absolute electron and positron fluxes from PAMELA/Fermi and Dark Matter
• Cosmic Ray Anomalies and Dark Matter Annihilation to Muons via a Higgs Portal Hidden Sector
• Higgsino dark matter model consistent with galactic cosmic ray data and possibility of discovery at LHC-7
• MiXDM: Cosmic Ray Signals from Multiple States of Dark Matter
• Superparticle Signatures: from PAMELA to the LHC