Searching for Neutrinos from WIMP Annihilations in the Galactic Stellar Disk

TL;DR

This paper proposes that neutrino signals from WIMP annihilations in the Galactic stellar disk could be significantly higher than halo signals, offering a new detection avenue for dark matter with large neutrino detectors.

Contribution

It introduces the idea that WIMP annihilation neutrino fluxes are enhanced in the stellar disk, providing a potentially more detectable signal than halo-based searches.

Findings

Neutrino flux from WIMP annihilations in the stellar disk is over ten times higher than from the halo.

Estimated neutrino fluxes are comparable to diffuse high-energy neutrino signals from cosmic-ray interactions.

Detection of these signals could help identify dark matter properties and distribution.

Abstract

Weakly interacting massive particles (WIMPs) are a viable candidate for the relic abundance of dark matter (DM) produced in the early universe. So far WIMPs have eluded direct detection through interactions with baryonic matter. Neutrino emission from accumulated WIMP annihilations in the solar core has been proposed as a signature of DM, but has not yet been detected. These null results may be due to small scale DM density fluctuations in the halo with the density of our local region being lower than the average (around 0.3 GeV/cm^3 ). However, the accumulated neutrino signal from WIMP annihilations in the Galactic stellar disk would be insensitive to local density variations. Inside the disk, dark matter can be captured by stars causing an enhanced annihilation rate and therefore a potentially higher neutrino flux than what would be observed from elsewhere in the halo. We estimate a neutrino flux from the WIMP annihilations in the stellar disk to be enhanced by more than an order of magnitude compared to the neutrino fluxes from the halo. We offer a conservative estimate for this enhanced flux, based on the WIMP-nucleon cross-sections obtained from direct-detection experiments by assuming a density of around 0.3 GeV/cm^3 for the local DM. We also compare the detectability of these fluxes with a signal of diffuse high energy neutrinos produced in the Milky Way by the interaction of cosmic rays (CRs) with the interstellar medium (ISM). These comparative signals should be observable by large neutrino detectors.