# High energy neutrinos from the Sun

## TL;DR

This paper estimates the flux of high-energy neutrinos from the Sun resulting from cosmic ray interactions, showing it exceeds atmospheric neutrino flux at TeV energies and could be detected by neutrino telescopes like KM3NeT.

## Contribution

The study uses recent HAWC data to refine the solar neutrino flux estimate, accounting for magnetic field effects on cosmic ray absorption, and highlights the detectability of this flux.

## Key findings

- Solar neutrino flux at 1 TeV exceeds atmospheric flux by over ten times.
- The flux has a distinct spectrum and flavor composition.
- KM3NeT can potentially detect this solar neutrino flux.

## Abstract

The Sun is a main source of high energy neutrinos. These neutrinos appear as secondary particles after the Sun absorbs high-energy cosmic rays, that find there a low-density environment (much thinner than our atmosphere) where most secondary pions, kaons and muons can decay before they lose energy. The main uncertainty in a calculation of the solar neutrino flux is due to the effects of the magnetic fields on the absorption rate of charged cosmic rays. We use recent data from HAWC on the cosmic-ray shadow of the Sun to estimate this rate. We evaluate the solar neutrino flux and show that at 1 TeV it is over ten times larger than the atmospheric one at zenith theta_z=30^o/150^o. The flux that we obtain has a distinct spectrum and flavor composition, and it could be detected in current and upcoming neutrino telescopes. KM3NeT, in particular, looks very promising: it will see the Sun high in the sky (the atmospheric background is lower there than near the horizon) and expects a very good angular resolution (the Sun's radius is just 0.27^o).