Possible Bose-Einstein condensation of α particles in the ground state of nuclear matter

Abstract

The phase diagram of isospin-symmetric chemically equilibrated mixture of alpha particles and nucleons is studied in the mean-field approximation. Skyrme-like parametrization is used for the mean-field potentials as functions of partial densities of nucleons and alphas. We find that there is a threshold value a* of the parameter a(N-alpha) which describes the attractive interaction between alpha-particles and nucleons. At a(N-alpha)<a* the ground state of nuclear matter at zero temperature behaves as a pure system of interacting nucleons, whereas at a(N-alpha)>a* the nuclear ground state includes also a nonzero fraction of alphas. We demonstrate that the equation of state of such alpha-N system includes both the first-order liquid-gas phase transitions and the Bose-Einstein condensation of alpha particles.