Neutrino emissivity of anisotropic neutron superfluids

TL;DR

This paper investigates how anisotropic superfluid energy gaps and residual Fermi-liquid interactions affect neutrino energy losses in neutron superfluids, providing analytical formulas and quantifying the suppression effects due to anisotropy.

Contribution

It offers new analytical expressions for neutrino emissivity in anisotropic neutron superfluids considering Fermi-liquid interactions, improving upon previous average-angle models.

Findings

Anisotropy causes approximately 15% suppression of pair recombination neutrino emission.

Spin-wave decay neutrino emission is substantially suppressed by anisotropy.

Residual Fermi-liquid interactions increase neutrino energy losses by about 5%.

Abstract

We examine the influence of the anisotropy of the superfluid energy gap and residual Fermi-liquid interactions in the triplet-correlated neutron liquid onto neutrino energy losses through neutral weak currents. The neutrino-pair emission caused by the pair breaking and formation processes and by the spin-wave decays is considered for the case of the $^{3}P_{2}$ pairing in the state with $m_{j}=0$. The simple analytical formulae are obtained. A comparison with the previous results of the average-angle approach shows that the gap anisotropy leads to quenching of the neutrino emissivity caused by the pair recombination processes on about 15% and to substantial suppression of the spin-wave decays. Residual particle-hole interactions increase the energy losses in both the channels on about 5%.