Nuclear liquid drop model revisited

Oyamatsu, Kazuhiro*; Iida, Kei*; Koura, Hiroyuki   

Liquid drop model is a representative model to describe binding energy and size of nuclei. This model is conventional and well reproduces bulk properties of nuclei even in current studies on nuclei. Nowadays structure of neutron-rich nuclei is paid attention to not only in nuclear physics but also in astrophysics because these nuclei play a quite important role to solve a problem of origin of elements in universe. In this paper, we investigate nuclear symmetry energy and nuclear surface energy by using the nuclear liquid drop model with some higher-order terms. The coefficients of these term are determined so as to reproduce measured nuclear masses of approximately 2200 nuclides. From this analysis, we find an indication that the fourth-order term of the symmetry energy is required and the curvature term of it is negligible. Regarding a mass-number dependency on nuclear radius, we also find that the dependency of lighter nuclei (typically with mass number, A, less than 50) is larger than that of heavier nuclei.