The equation of state of low and intermediate density nuclear matter with light and medium clusters up to A=50

Abstract

Nuclear matter at low and intermediate density and moderate temperature minimizes its energy by forming nuclear clusters. Most previous theoretical investigations ignored the formation of the heavy clusters and focused on light clusters with mass number up to A = 4. In this work, clusters with mass number up to A = 50 are included in nuclear matter and treated by the Nuclear Statistical Equilibrium model (NSE) which states that clusters are in chemical equilibrium with the free nucleons in the surrounding vapour. The Nuclear Statistical Equilibrium (NSE) model was modified by using density-dependent binding energies of clusters where the clusters’ binding energies decrease as the surrounding medium density increases. In fact, clusters undergo the Mott transition and get dissolved as the density of nuclear matter increases due to the medium effects. The Pauli Blocking is found to be the prominent factor that affects clusters’ binding energies. It was found that heavier clusters play a significant role in low and intermediate density symmetric nuclear matter composition and should be included in the equation of state (EoS) to make the study more realistic. Finally, these clusters reduce the critical temperature by several MeVs.