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Phase-space excluded-volume approach for light clusters in a nuclear medium

Rui Wang1,*,†, Zhen Zhang2,‡, Stefano Burrello3,§, Maria Colonna3,∥, and Edoardo G. Lanza1,¶

  • *Present Address: INFN, Laboratori Nazionali del Sud, I-95123 Catania, Italy.
  • †Contact author: rui.wang@lns.infn.it
  • ‡Contact author: zhangzh275@mail.sysu.edu.cn
  • §Contact author: burrello@lns.infn.it
  • ∥Contact author: colonna@lns.infn.it
  • Contact author: edoardo.lanza@ct.infn.it
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Phys. Rev. C 113, 034624 – Published 31 March, 2026

DOI: https://doi.org/10.1103/4py6-jyk8

Abstract

We present a phase-space excluded-volume approach applicable to both nuclear matter and nonequilibrium processes, such as heavy-ion collisions, to account for in-medium effects on light clusters. In this approach, light clusters can exist only if the nucleon one-body phase-space occupation of the surrounding nuclear medium—including explicit contributions from light clusters—is sufficiently low. The nucleon occupation is determined self-consistently by accounting for the interplay between in-medium effects and thermodynamic properties, thereby improving upon the conventional treatment based on an uncorrelated medium (i.e., an overall nucleonic Fermi-Dirac distribution) typically employed in studies of light clusters in nuclear matter. We apply the approach to evaluate the Mott momenta and the fractions of light clusters in nuclear matter. Their differences from results obtained under the uncorrelated-medium assumption are found to be moderate. The main advantage of the present approach lies in its ability to be integrated into dynamical models, enabling more accurate studies of in-medium effects on light clusters, based on their measured yields in heavy-ion collisions.

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Phys. Rev. C 113, 034624– Published 31 March, 2026
  • Received 24 June 2025
  • Revised 10 November 2025
  • Accepted 11 February 2026
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