Coupled-channel representation to describe fine structure in the α decay of odd-mass Bk isotopes

An extension of the multichannel cluster model (MCCM) is presented to investigate the a decay of odd-mass Bk isotopes from their ground states to more than one rotational band in the daughter Am nuclei. In these cases, the alpha intensity for the other rotational bands is comparable or dominant with respect to the favored one. Three rotational bands are taken into account for the alpha decays of Bk-243,Bk-245,Bk-247 from their 3/2(-) ground states. The available experimental data concerning fine structure and a-decay half-lives are well reproduced within the same framework. Moreover, the ground-state and favored rotational bands are considered for the alpha decay of Bk-249 from its 7/2(+) ground state. The calculated results also show good agreement with the latest experimental data [I. Ahmad et al., Phys. Rev. C 87, 054328 (2013)]. This is the first calculation of the alpha transitions to several rotational bands including favored and unfavored ones within the coupled-channel framework.