Effects of neutrino magnetic moment and charge radius constraints and medium modifications of the nucleon form factors on the neutrino mean free path in dense matter

TL;DR

This paper investigates how neutrino charge radius and magnetic moment constraints, along with in-medium modifications of nucleon form factors, affect neutrino interactions and mean free path in dense matter, with implications for neutron star cooling.

Contribution

It provides a comprehensive analysis of the combined effects of neutrino form factors and in-medium nucleon modifications on neutrino mean free path in dense matter, using relativistic models.

Findings

Neutrino form factors decrease the mean free path by 12-58%.

In-medium modifications further reduce the neutrino mean free path.

Results suggest a deceleration of neutron star cooling due to these effects.

Abstract

Effects of neutrino charge radius and magnetic moment constraints obtained from the astrophysical observations and reactor experiments, as well as in-medium modifications of the weak and electromagnetic nucleon form factors of the matter on the neutrino electroweak interaction with dense matter, are estimated. We use a relativistic mean-field model for the in-medium effective nucleon mass and quark-meson coupling model for nucleon form factors. We analyze the neutrino scattering cross section and mean free path in cold nuclear matter. We find that the increase of the cross section relative to that without neutrino form factors results in the decrease of the neutrino mean free path when neutrino form factors and the in-medium modifications of the nucleon weak and electromagnetic form factors are simultaneously considered. The quenching of the neutrino mean free path is evaluated to be about 12-58\% for the values of $\mu_\nu = 3 \times 10^{-12} \mu_B$ and $R_\nu = 3.5 \times 10^{-5}~\textrm{MeV}^{-1}$ compared with that obtained for the $\mu_\nu =0$ and $R_\nu =0$. The decrease of the neutrino mean free path is expected to decelerate the cooling of neutron stars. Each contribution of the neutrino form factors to the neutrino mean free path is discussed.