Improvement of gross theory of beta-decay for application to nuclear data

崩壊の大局的理論の改良と核データへの応用

小浦 寛之   ; 吉田 正*; 橘 孝博*; 千葉 敏*

Koura, Hiroyuki; Yoshida, Tadashi*; Tachibana, Takahiro*; Chiba, Satoshi*

A theoretical study of decay and delayed neutron has been carried out with a global -decay model: the gross theory. In a fissioning nucleus, neutrons are produced by the decay of neutron-rich fission fragments. This is known as delayed neutrons. The gross theory of the decay is based on a consideration of the sum rule of the -strength function, and gives reasonable results of -decay rates and delayed neutron in the entire nuclear mass region. We re-analyze and improve the theory on the strength functions and one-particle level densities. We focus on the spin-parity of decaying nucleus, and a hindrance treatment is introduced for the allowed transition on parity-mismatching nuclei. By using the improved gross theory, the ability of theoretically reproduction (and also prediction) on -decay rates, delayed-neutron emission probabilities, decay heat, will be discussed. In the process, we make a new code of the gross theory of - decay including the improved parts. We will show the code, which can be distributed for the nuclear data community.