Repulsive four-body interactions of α particles and quasistable nuclear α-particle condensates in heavy self-conjugate nuclei

We study the effects of repulsive four-body interactions of alpha-particles on nuclear alpha-particle condensates in heavy self-conjugate nuclei using a semianalytic approach, and find that the repulsive four-body interactions could decrease the critical number of alpha-particles, beyond which quasistable alpha-particle condensate states can no longer exist, even if these four-body interactions make only tiny contributions to the total energy of the Hoyle-like state of O-16. Explicitly, we study eight benchmark parameter sets, and find that the critical number N-cr decreases by vertical bar Delta N-cr vertical bar similar to 1-4 from N-cr similar to 11 with vanishing four-body interactions. We also discuss the effects of four-body interactions on energies and radii of alpha-particle condensates. Our study can be useful for future experiments to study alpha-particle condensates in heavy self-conjugate nuclei. Also, the experimental determination of N-cr will eventually help establish a better understanding on the alpha-particle interactions, especially the four-body interactions.