Neutrinos from cosmic ray interactions in the Sun

Abstract

Cosmic rays hitting the solar atmosphere generate neutrinos that interact and oscillate in the Sun and oscillate on the way to Earth. These neutrinos could potentially be detected with neutrino telescopes and will be a background for searches for neutrinos from dark matter annihilation in the Sun. We calculate the flux of neutrinos from these cosmic ray interactions in the Sun and also investigate the interactions near a detector on Earth that give rise to muons. We compare this background with both regular Earth-atmospheric neutrinos and signals from dark matter annihilation in the Sun. Our calculation is performed with an event-based Monte Carlo approach that should be suitable as a simulation tool for experimental collaborations. Our program package is released publicly along with this paper.

Status of Dark Matter Searches (Rapporteur Talk)

“…Cosmic rays interacting in the solar atmosphere can produce high-energy neutrinos that form a natural background to dark matter searches from the Sun. This solar atmospheric neutrino flux is an irreducible background for Solar DM searches and forms a sensitivity floor that is reached when the expected event rates from solar atmospheric neutrinos equals that of DM-induced neutrinos [44,45,46,47]. While the DM induced neutrino spectrum strongly depends on the dark matter mass, m χ , and annihilation channels, the energy spectrum of solar atmospheric neutrinos is more predictable.…”

High energy neutrinos from cosmic ray interactions in the Sun

“…Our calculation is divided in two parts: the calculation of the production fluxes of neutrinos in the solar atmosphere is performed with the code MCEq [18,19] and the propagation of the neutrinos from production to a detector on Earth is done with an updated version of the code WimpSim [13,17,20,21]. MCEq is a one-dimensional cascade equation solver from which we obtain the neutrino production fluxes in the atmosphere as function of energy E, impact parameter b, flavour α and travelled path length in the atmosphere.…”

“…The SAν flux has been studied before [4,[7][8][9][10][11][12] as well as in recent studies [13][14][15][16]. In Ref.…”

“…In Ref. [13] we have performed an updated calculation of the SAν flux at Earth including a full threeflavour treatment of oscillations and interactions. We have used an event-based Monte Carlo code for our calculations which is released publicly [17] and allows for the calculation of neutrino or muon fluxes in a detector at Earth.…”

“…[13] we have performed an updated calculation of the SAν flux at Earth including a full threeflavour treatment of oscillations and interactions. We have used an event-based Monte Carlo code for our calculations which is released publicly [17] and allows for the calculation of neutrino or muon fluxes in a detector at Earth. Our improvements include, apart from the aforementioned interaction and oscillation treatment, for example the use of updated models for the incoming CR flux, the solar density model as well as the hadronic interaction models used.…”