Clustered Nature of Hot and Dense Nuclear Matter: A quantum statistical approach

Abstract

The equilibrium abundances of the light clusters $^2$H, $^3$H, $^3$He, $^4$He in hot nuclear matter at densities near the saturation density are of essential interest for nuclear physics and astrophysical applications, but theoretical approaches give diverging answers. We compare the quantum statistical approach with the recently discussed phase-space excluded-volume approach. We analyze the main ingredients, the Mott momentum, and the momentum distribution functions of light clusters. We observe a sharp decrease in cluster abundances as the density approaches saturation density, that is also seen in a relativistic mean-field calculation. We outline possible improvements in determining the composition of hot, dense matter in thermodynamic equilibrium. Non-equilibrium effects must be taken into account to investigate cluster formation in heavy-ion collisions.