Phase diagram of alpha matter with Skyrme-like scalar interaction
Abstract
The equation of state and phase diagram of strongly interacting matter composed of α particles are studied in the mean-field approximation. The particle interactions are included via a Skyrme-like mean field, containing both attractive and repulsive terms. The model parameters are found by fitting known values of binding energy and baryon density in the ground state of α matter, obtained from microscopic calculations by Clark and Wang. Thermodynamic quantities of α matter are calculated in the broad domains of temperature and baryon density, which can be reached in heavy-ion collisions at intermediate energies. The model predicts both first-order liquid-gas phase transition and Bose-Einstein condensation of α particles. We present the profiles of scaled variance, sound velocity and isochoric heat capacity along the isentropic trajectories of α matter. Strong density fluctuations are predicted in the vicinity of the critical point at temperature Tc≈ 14~MeV and density nc≈ 0.012~fm-3.