Spin Response and Neutrino Emissivity of Dense Neutron Matter

TL;DR

This paper investigates the spin response of dense neutron matter and its implications for neutrino emission, using advanced computational techniques to analyze the response at various energies relevant to supernova physics.

Contribution

It provides new constraints on the spin response function of neutron matter at zero momentum transfer using sum-rules and high-frequency response calculations.

Findings

Spin response peaks at 40-60 MeV frequency.

Rapid decay of response above 100 MeV.

Enhanced low-energy response may increase neutrino emission.

Abstract

We study the spin response of cold dense neutron matter in the limit of zero momentum transfer, and show that the frequency dependence of the long-wavelength spin response is well constrained by sum-rules and the asymptotic behavior of the two-particle response at high frequency. The sum-rules are calculated using Auxiliary Field Diffusion Monte Carlo technique and the high frequency two-particle response is calculated for several nucleon-nucleon potentials. At nuclear saturation density, the sum-rules suggest that the strength of the spin response peaks at $\omega \simeq$ 40--60 MeV, decays rapidly for $\omega \geq $100 MeV, and has a sizable strength below 40 MeV. This strength at relatively low energy may lead to enhanced neutrino production rates in dense neutron-rich matter at temperatures of relevance to core-collapse supernova.