Refinement of the gross theory of nuclear {beta}-decay, and hindrance of the first-forbidden transition of rank 1 Nakata, Hidehiko [Waseda Univ., Tokyo (Japan). Dept. of Physics]; Tachibana, Takahiro; Yamada, Masami 66 PHYSICS; BETA DECAY; HALF-LIFE; ODD-ODD NUCLEI; SPIN; FORBIDDEN TRANSITIONS; FERMI INTERACTIONS; GAMOW-TELLER RULES; FT VALUE; BETA SPECTRA; FISSION PRODUCTS; COMPUTERIZED SIMULATION Recently the gross theory of nuclear {beta}-decay was refined for odd-odd nuclei. In this refinement, the effect of the selection rule of {beta}-transitions from the ground states of odd-odd nuclei to those of even-even nuclei was taken into account based on a statistical consideration. The transitions to the first 2{sup +} excited states in even-even nuclei were also taken into account according to the selection rule approximately. In that study, it was found that the transitions between 1{sup -} ground states of the odd-odd nuclei and 0{sup +} ground states of even-even nuclei, belonging to the first-forbidden transitions of rank 1, are strongly hindered. A reduction factor was introduced for the transitions to the ground states of even-even nuclei to take into account this hindrance. It was also found that the strength functions of the Gamow-Teller transitions obtained from the conventional gross theory are underestimated by a factor of about 3. In order to improve this underestimation, the Lorentz-type function was adopted for the one-particle strength function in the model instead of the hyperbolic-secant-type function. In the present study we have newly analyzed the experimental ft-values of odd-A nuclei, and found that the first-forbidden transitions of rank 1 are also considerably hindered between the ground states. Following the above refinement we have calculated the {beta}-ray spectra of some odd-odd short-lived fission products with the use of the refined gross theory. These results are compared not only with the experiments by Rudstam et al. but also with the conventional gross theory. (author) Japan Atomic Energy Research Inst., Tokyo (Japan) OSTI as DE97758661 Japan 1997-03-01 English Conference Conference: ISND-1: 1. internet symposium on nuclear data, Tokai (Japan), 8 Apr - 15 Jun 1996; Other Information: PBD: Mar 1997; Related Information: Is Part Of Proceedings of the first internet symposium on nuclear data; Fukahori, Tokio; Iwamoto, Osamu; Nakagawa, Tsuneo [eds.] [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment]; PB: 285 p. Medium: ED; Size: pp. 159-166 https://doi.org/ ON: DE97758661 [] JAERI-Conf-97-004; CONF-9604220-; INDC(JPN)-178/U Other: ON: DE97758661; TRN: JP9708201 JPN; SCA: 663210; PA: JPN-97:008201; EDB-97:134272; SN: 97001850453 2018-05-18 530409 https://www.osti.gov/etdeweb/servlets/purl/530409