The equation of state and the phase diagram of an isospin-symmetric chemically equilibrated mixture of a particles and nucleons (N) are studied in the mean-field approximation. We use a Skyrme-like parametrization of mean-field potentials as functions of the partial densities of particles. The parameters of these potentials are chosen by fitting the known properties of pure N- and pure a-matters at zero temperature. The sensitivity of results to the choice of the aN attraction strength is investigated. The phase diagram of the a − N mixture is studied with a special attention paid to the liquid-gas phase transitions and the Bose–Einstein condensation of a particles. We have found two first-order phase transitions, stable and metastable, which differ significantly by the fractions of a’s. It is shown that the states with a condensate are metastable.
Phase transitions and Bose-Einstein condensation in
α
-nucleon matter