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 noninteracting neutrons. By adopting a non-self-consistent 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.

• Received 16 June 2020
• Revised 18 September 2020
• Accepted 14 October 2020

DOI:https://doi.org/10.1103/PhysRevC.102.055802