Abstract
The ground-state properties of a system of liquid He4 and of an artificial mass-3 boson system are calculated by a variational procedure employing a Jastrow-type trial wave function in conjunction with the Kirkwood superposition approximation for the three-particle distribution function. The parameters in a Lennard-Jones 6-12 potential are determined in a self-consistent manner and the energy, pressure, velocity of sound, pair-distribution function, and liquid-structure function are calculated as functions of density. The agreement between the theoretical and experimental results is good.