Enhanced neutrino signals from dark matter annihilation in the Sun via metastable mediators

TL;DR

This paper demonstrates that in secluded dark matter models with metastable mediators, neutrino signals from the Sun are significantly enhanced at high energies due to reduced absorption, improving detection prospects.

Contribution

It introduces a model where long-lived mediators decay outside the solar core, leading to increased high-energy neutrino fluxes compared to standard scenarios.

Findings

Neutrino flux is enhanced at energies > 100 GeV

Neutrino absorption is reduced due to decay location

High-energy neutrino detection rates increase significantly

Abstract

We calculate the neutrino signal resulting from annihilation of secluded dark matter in the Sun. In this class of models, dark matter annihilates first into metastable mediators, which subsequently decay into Standard Model particles. If the mediators are long lived, they will propagate out from the dense solar core before decaying. High energy neutrinos undergo absorption in the Sun. In the standard scenario in which neutrinos are produced directly in the centre of the Sun, absorption is relevant for E > 100 GeV, resulting in a significant suppression of the neutrino spectrum beyond E ~ 1 TeV. In the secluded dark matter scenario, the neutrino signal is greatly enhanced because neutrinos are injected away from the core, at lower density. Since the solar density falls exponentially with radius, metastable mediators have a significant effect on the neutrino flux, even for decay lengths which are small compared to the solar radius. Moreover, since neutrino detection cross sections grow with energy, this enhancement of the high energy region of the neutrino spectrum would have a large effect on overall event rates.