$\alpha$-decay half-lives of odd-mass nuclei with differences between neutron and proton distributions

Effects of differences between neutron and proton distributions on $\alpha$ decay are investigated for odd-mass nuclei within the generalized density-dependent cluster model. The neutron skin thickness is employed to gauge the differences and it is considered in numerically computing the double-folding $\alpha$-nucleus potentials. In terms of the characteristic of odd-mass $\alpha$ emitters, special attention is paid to the $\alpha$ decays from ground or isomeric states which end in the ground states of daughter nuclei and furthermore belong to favored $\alpha$ decays. The calculations with the neutron skin thickness yield shorter half-lives, suggesting a smaller preformation factor. This is quite consistent with the conclusions for even-even $\alpha$ emitters. Moreover, $\alpha$-decay calculations are extended for odd-mass isomers and superheavy nuclei. The calculated $\alpha$-decay half-lives are found to be in good agreement with the experimental data.

Figure 1

Logarithm of the ratio $T^{\mathrm{calc}}/T^{\mathrm{expt}}$ as a function of the neutron number $N$ of the parent nuclei. Note that all the $\alpha$ decays of odd-mass nuclei proceed from ground or isomeric states to ground states and belong to favored $\alpha$ decays, where the rms charge radii of the corresponding daughter nuclei are known in experiments. The theoretical results are calculated with the neutron skin-type distribution. Black circles denote the $\alpha$ decays from ground states and red stars denote the $\alpha$ decays from isomeric states.