Exploring neutrinos from proton decays catalyzed by GUT monopoles in the Sun

TL;DR

This paper investigates neutrino signals from proton decays catalyzed by GUT monopoles in the Sun, analyzing specific decay modes and their detection prospects at Super-Kamiokande using detailed simulations.

Contribution

It introduces a detailed simulation of neutrino spectra from monopole-induced proton decays and evaluates Super-Kamiokande's sensitivity to these signals across different decay modes.

Findings

$K^0$ decay produces 236 MeV monoenergetic $ u_d$ neutrinos.

The $p ightarrow d d K^0$ mode offers the best detection potential.

Super-Kamiokande can set meaningful limits on monopole fluxes for these decay modes.

Abstract

We explore the neutrino signals from proton decays catalyzed by GUT monopoles in the Sun. Three typical proton decay modes, $p \rightarrow e^+ + (\rho^0, \eta, \omega...) \rightarrow \pi^+$, $p \rightarrow \mu^+ K^0$ and $p \rightarrow \bar{\nu}_e \pi^+$, have been analyzed for the Super-Kamiokande experiment. The monopole-induced neutrinos arise from interactions and subsequent decays of the proton decay products. To obtain the neutrino energy spectra, we use the Geant4 software to simulate propagations of daughter particles in the highly-dense solar center. It is found that $K^0$ can produce a large amount of 236 MeV monoenergetic $\nu_\mu$ neutrinos through the charge exchange process $K^0 + p \rightarrow K^+ + n$ and the subsequent decay $K^+ \rightarrow \mu^+ \nu_\mu$ at rest. Based on this interesting feature, $p \rightarrow \mu^+ K^0$ can give the best discovery potential among three decay modes for most of the parameter space. In addition, we present the Super-Kamiokande sensitivities to the monopole flux for three proton decay modes.