Ab initio calculation of double mass differences for near-magic nuclei

Abstract

Double mass differences between nuclei with a magic number of protons (neutrons) and their neighbors differing from them by one or two protons (neutrons) are calculated within the semimicroscopic model proposed recently for the nuclear pairing problem. The main term in the effective nucleon interaction is calculated on the basis of the realistic Argonne nucleon-nucleon potential v18. This term is supplemented with a small phenomenological term involving one universal parameter common to protons and neutrons. The double mass differences are calculated for the proton neighbors of the Z = 82, 50, 28, and 20 lead, tin, nickel, and calcium isotopic chains and for the neutron neighbors of the N = 126, 82, 50, and 20 isotonic chains. The corrections to the model that are induced by the contribution of low-lying surface vibrations (phonons) are discussed.