Accurate calculations of the WIMP halo around the Sun and prospects for its gamma-ray detection

Abstract

Galactic weakly interacting massive particles (WIMPs) may scatter off solar nuclei to orbits gravitationally bound to the Sun. Once bound, the WIMPs continue to lose energy by repeated scatters in the Sun, eventually leading to complete entrapment in the solar interior. While the density of the bound population is highest at the center of the Sun, the only observable signature of WIMP annihilations inside the Sun is neutrinos. It has been previously suggested that although the density of WIMPs just outside the Sun is lower than deep inside, gamma rays from WIMP annihilation just outside the surface of the Sun, in the so called WIMP halo around the Sun, may be more easily detected. We here revisit this problem using detailed Monte Carlo simulations and detailed composition and structure information about the Sun to estimate the size of the gamma-ray flux. Compared to earlier simpler estimates, we find that the gamma-ray flux from WIMP annihilations in the solar WIMP halo would be negligible; no current or planned detectors would be able to detect this flux.

18 pages, 7 figures, latex, updated to match published version.

References in corpus (6)

• CMB constraints on Dark Matter models with large annihilation cross-section
• Gamma-ray emission from the solar halo and disk: a study with EGRET data
• Dark matter in the solar system I: The distribution function of WIMPs at the Earth from solar capture
• Dark matter in the solar system II: WIMP annihilation rates in the Sun
• Gamma-rays from halos around stars and the Sun
• Dark matter bound to the Solar System: consequences for annihilation searches

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• High Energy Electron Signals from Dark Matter Annihilation in the Sun
• Constraints on Spin-Dependent Dark Matter Scattering with Long-Lived Mediators from TeV Observations of the Sun with HAWC
• First Observation of Time Variation in the Solar-Disk Gamma-Ray Flux with Fermi
• Impact of Dark Matter Velocity Distributions on Capture Rates in the Sun
• Solar $\gamma$-rays as a Complementary Probe of Dark Matter
• Search for dark matter signatures in the gamma-ray emission towards the Sun with the Fermi Large Area Telescope
• The capture of dark matter particles through the evolution of low-mass stars
• A tale of dark matter capture, sub-dominant WIMPs, and neutrino observatories
• Constraints on dark matter models from a Fermi LAT search for high-energy cosmic-ray electrons from the Sun
• WIMP diffusion in the solar system including solar WIMP-nucleon scattering
• A search for dark matter cosmic-ray electrons and positrons from the Sun with the Fermi Large Area Telescope
• The WIMP capture process for dark stars in the early universe
• Constraints on Dark Matter from the Moon
• Annihilation of NMSSM neutralinos in the Sun and neutrino telescope limits
• Searching for Spurious Solar and Sky Lines in the Fermi-LAT Spectrum
• Dark Gamma Ray Bursts
• Prospects for the detection of Dark Matter with Long-lived Mediators in the Sun using the Southern Wide-field Gamma-ray Observatory
• Indirect searches for dark matter with the Fermi LAT instrument