Enhanced Muonization by Active-Sterile Neutrino Mixing in Protoneutron Stars

TL;DR

This paper investigates how active-sterile neutrino mixing influences muonization in protoneutron stars during supernovae, revealing that sterile neutrino production enhances muonization through feedback mechanisms, with implications for supernova dynamics.

Contribution

It introduces a detailed analysis of active-sterile neutrino mixing effects on protoneutron star composition and muonization, emphasizing the feedback on lepton number and potential impacts on supernova simulations.

Findings

Sterile neutrino production is dominated by MSW conversion of antineutrinos.

Increased sterile neutrino escape enhances muonization in the PNS.

Feedback effects significantly influence neutrino emission and PNS evolution.

Abstract

We study $\nu_\mu$-$\nu_s$ and $\bar\nu_\mu$-$\bar\nu_s$ mixing in the protoneutron star (PNS) created in a core-collapse supernova (CCSN). We point out the importance of the feedback on the general composition of the PNS in addition to the obvious feedback on the $\nu_\mu$ lepton number. We show that for our adopted mixing parameters $\delta m^2\sim 10^2$~keV$^2$ and $\sin^2 2\theta$ consistent with the current constraints, sterile neutrino production is dominated by the Mikheyev-Smirnov-Wolfenstein conversion of $\bar\nu_\mu$ into $\bar\nu_s$ and that the subsequent escape of $\bar\nu_s$ increases the $\nu_\mu$ lepton number, which in turn enhances muonization of the PNS primarily through $\nu_\mu+n\to p+\mu^-$. While these results are qualitatively robust, their quantitative effects on the dynamics and active neutrino emission of CCSNe should be evaluated by including $\nu_\mu$-$\nu_s$ and $\bar\nu_\mu$-$\bar\nu_s$ mixing in the simulations.