Dirac neutrino magnetic moment and a possible time evolution of the neutrino signal from a supernova

TL;DR

This paper explores how the magnetic moment of Dirac neutrinos can cause time-dependent signals in supernova neutrino fluxes, potentially revealing pulsating neutrino signals linked to magnetic field interactions.

Contribution

It introduces the idea that neutrino magnetic moments in a specific range can lead to observable time evolution of supernova neutrino signals due to helicity conversion in magnetic fields.

Findings

Neutrino magnetic moments between 10^{-13} and 10^{-12} μ_B can induce flux variations.

Resonance transitions in supernova magnetic fields can cause pulsating neutrino signals.

A rotating magnetar could produce a neutrino pulsar observable from Earth.

Abstract

We analyze the influence of neutrino helicity conversion, $\nu_L \to \nu_R$, on the neutrino flux from a supernova caused by the interaction of the Dirac neutrino magnetic moment with a magnetic field. We show that if the neutrino has a magnetic moment in the interval $10^{-13} \, \mu_{\rm B} < \mu_\nu < 10^{-12} \, \mu_{\rm B}$ and provided that a magnetic field of $\sim 10^{13} - 10^{14}$ G exists in the supernova envelope, a peculiar kind of time evolution of the neutrino signal from the supernova caused by the resonance transition $\nu_L \to \nu_R$ in the magnetic field of the envelope can appear. If a magnetar with a poloidal magnetic field is formed in a supernova explosion, then the neutrino signal could have a pulsating behavior, i.e., a kind of a neutrino pulsar could be observed, when it rotates around an axis that does not coincide with its magnetic moment and when the orientation of its rotation axis is favourable for our observation.