Leptonic contribution to the bulk viscosity of nuclear matter

TL;DR

This paper estimates the leptonic contribution to the bulk viscosity of nuclear matter, showing that electron-muon conversions dominate at certain frequencies and low temperatures, impacting neutron star oscillation damping.

Contribution

It introduces a novel calculation of leptonic processes' impact on bulk viscosity in nuclear matter, highlighting their significance at specific conditions.

Findings

Leptonic processes dominate bulk viscosity at kHz frequencies and low temperatures.

Electron-muon conversions are the primary leptonic contribution.

The results impact understanding of neutron star oscillation damping.

Abstract

For beta-equilibrated nuclear matter we estimate the contribution to the bulk viscosity from purely leptonic processes, namely the conversion of electrons to and from muons. For oscillation frequencies in the kiloHertz range, we find that this process provides the dominant contribution to the bulk viscosity when the temperature is well below the critical temperature for superconductivity or superfluidity of the nuclear matter.