Galactic Substructure and Energetic Neutrinos from the Sun and the Earth

TL;DR

This paper studies how Galactic substructure influences the flux of energetic neutrinos from WIMP annihilation in the Sun and Earth, highlighting potential time variations and the importance of past dark matter densities.

Contribution

It introduces the concept that Galactic substructure causes time-dependent neutrino signals and emphasizes the significance of historical dark matter densities in detection.

Findings

Galactic substructure induces time variation in neutrino flux.

The neutrino flux may reflect past dark matter densities.

A potential signature is the ratio of direct to indirect detection rates.

Abstract

We consider the effects of Galactic substructure on energetic neutrinos from annihilation of weakly-interacting massive particles (WIMPs) that have been captured by the Sun and Earth. Substructure gives rise to a time-varying capture rate and thus to time variation in the annihilation rate and resulting energetic-neutrino flux. However, there may be a time lag between the capture and annihilation rates. The energetic-neutrino flux may then be determined by the density of dark matter in the Solar System's past trajectory, rather than the local density. The signature of such an effect may be sought in the ratio of the direct- to indirect-detection rates.