Quasiparticle properties of a single alpha particle in cold neutron matter

TL;DR

This paper investigates the in-medium quasiparticle properties of a single alpha particle embedded in a dilute neutron gas, providing insights relevant to nuclear matter in astrophysical and heavy-ion collision contexts.

Contribution

It introduces a simplified impurity model to analyze alpha particle properties in neutron matter using a ladder approximation, extending Fermi polaron analysis to nuclear physics.

Findings

Calculated energy shift of the alpha particle in neutron matter

Determined the effective mass and quasiparticle residue

Analyzed damping rates of the impurity quasiparticle

Abstract

Light clusters such as alpha particles and deuterons are predicted to occur in hot nuclear matter as encountered in intermediate-energy heavy-ion collisions and protoneutron stars. To examine the in-medium properties of such light clusters, we consider a much simplified system in which like an impurity, a single alpha particle is embedded in a zero-temperature, dilute gas of non-interacting neutrons. By adopting a non-selfconsistent ladder approximation for the effective interaction between the impurity and the gas, which is often used for analyses of Fermi polarons in a gas of ultracold atoms, we calculate the quasiparticle properties of the impurity, i.e., the energy shift, effective mass, quasiparticle residue, and damping rate.