Short-range nucleon correlations and neutrino emission by neutron stars

TL;DR

This paper investigates how short-range nucleon correlations influence neutrino emission and cooling processes in neutron stars, highlighting enhanced and previously suppressed URCA processes due to high-momentum nucleons.

Contribution

It provides a detailed evaluation of high-momentum tails in nucleon and electron distributions, revealing new conditions for URCA process activation in neutron stars.

Findings

Protons with momenta above the Fermi surface significantly enhance URCA processes.

Direct URCA processes can occur at lower proton concentrations than previously thought.

Hyperon stars exhibit faster neutrino cooling due to nucleon correlations.

Abstract

We argue that significant probability of protons with momenta above their Fermi surface leads for proton concentrations p/n > 1/8 to the enhancement of termally excited direct and modified URCA processes within a cold neutron star, and to a nonzero probability of direct URCA processes for small proton concentrations (p/n < 1/8). We evaluate high momentum tails of neutron, proton and electrons distributions within a neutron star. We expect also significantly faster neutrino cooling of hyperon stars.