On the Role of Neutrinos Telescopes in the Search for Dark Matter Annihilations in the Sun

TL;DR

This paper evaluates the potential of neutrino telescopes to detect dark matter annihilations in the Sun, considering current constraints and future experimental sensitivities, without assuming equilibrium between capture and annihilation rates.

Contribution

It provides a comprehensive analysis of dark matter detection prospects via neutrinos, considering both spin-dependent and spin-independent interactions and various annihilation channels, without assuming equilibrium.

Findings

Current direct detection bounds limit neutrino detection in future experiments for spin-independent interactions.

Future neutrino detectors can probe unique regions of parameter space not accessible to other methods.

Complementarity exists between neutrino telescopes and other dark matter detection experiments.

Abstract

The observation of GeV neutrinos coming from the Sun would be an unmistakable signal of dark matter. Current neutrino detectors have so far failed to detect such a signal, however, and bounds from direct and indirect dark matter searches may significantly restrict the possibility of observing it in future experiments such as Hyper-Kamiokande or IceCube-Gen2. In this work, we assess in the light of current data and of expected experimental sensitivities, the prospects for the detection of a neutrino signal from dark matter annihilations in the Sun. To be as general as possible, equilibrium between the capture and the annihilation rates in the Sun is not assumed in our analysis; instead, the dark matter scattering and annihilation cross sections are taken as free and independent parameters. We consider capture via both spin-dependent and spin-independent interactions, and annihilations into three representative final states: $b\bar b$, $W^+W^-$, and $\tau^+\tau^-$. We find that when the capture in the Sun is dominated by spin-independent interactions, current direct detection bounds already preclude the observation of a neutrino signal in future experiments. For capture via spin-dependent interactions, a strong complementarity is observed, over most of the parameter space, between future neutrino detectors and planned direct and indirect dark matter detection experiments, such as PICO-500 and CTA. In this case, we also identify some regions of the parameter space that can be probed, via the neutrino flux from the Sun, only by future neutrino experiments.