Shell-model half-lives for r-process waiting point nuclei including first-forbidden contributions

We have performed large-scale shell-model calculations of the half-lives and neutron-branching probabilities of the r-process waiting point nuclei at the magic neutron numbers N=50, 82, and 126. The calculations include contributions from allowed Gamow-Teller and first-forbidden transitions. We find good agreement with the measured half-lives for the N=50 nuclei with charge numbers Z=28-32 and for the N=82 nuclei 129Ag and 130Cd. The contribution of forbidden transitions reduce the half-lives of the N=126 waiting point nuclei significantly, while they have only a small effect on the half-lives of the N=50 and 82 r-process nuclei.Comment: 14 pages, 17 figures, submitted to Phys. Rev.

Half-lives of α\alpha-emitters approaching the N=Z line

The half-lives of newly observed $\alpha$-emitters $^{105}$Te and $^{109}$Xe [Seweryniak \textit{et al.}, Phys. Rev. C \textbf{73}, 061301(R) (2006); Liddick \textit{et al.}, Phys. Rev. Lett. \textbf{97}, 082501 (2006)] are investigated by the density-dependent cluster model. The half-lives of $\alpha$-emitters close to the N=Z line are also studied in a unified framework where the influence of the nuclear deformation is properly taken into account. Good agreement between model and data is obtained and some possible $\alpha$-emitters are suggested for future experiments.Comment: 9 pages, 3 figures, To appear in Phys. Rev.

Striving for a good life : the good lives model applied to released child molesters

The good lives model (GLM) is a strengths-based approach to offender rehabilitation in which treatment aims to equip offenders with the skills and resources necessary to satisfy primary goods, or basic human values, in personally meaningful and socially acceptable ways. The aim of the present research was to explore the practical utility of the GLM with a sample of released child molesters, and investigate the relationship between primary goods attainment and overall re-entry conditions (in terms of accommodation, social support and employment). Semi-structured interviews were conducted with 16 child molesters at one, three and six months following their release from prison. As expected, participants endorsed the majority of GLM primary goods with high importance, and positive re-entry experiences were associated with increased goods attainment. Implications for clinicians, policy makers and society as a whole are discussed

Shell-model half-lives for the N=82 nuclei and their implications for the r-process

We have performed large-scale shell-model calculations of the half-lives and neutron-branching probabilties of the r-process waiting point nuclei at the magic neutron number N=82. We find good agreement with the measured half-lives of 129Ag and 130Cd. Our shell-model half-lives are noticeably shorter than those currently adopted in r-process simulations. Our calculation suggests that 130Cd is not produced in beta-flow equilibrium with the other N=82 isotones on the r-process path.Comment: 4 pages, 3 figure

Alpha-decay half-lives and Q_alpha values of superheavy nuclei

The alpha-decay half-lives of recently synthesized superheavy nuclei (SHN) are investigated based on a unified fission model (UFM) where a new method to calculate the assault frequency of alpha-emission is used. The excellent agreement with the experimental data indicates the UFM is a useful tool to investigate these alpha-decays. It is found that the half-lives become more and more insensitive to the Q_alpha values as the atomic number increases on the whole, which is favorable for us to predict the half-lives of SHN. In addition, a formula is suggested to compute the Q_alpha values for the nuclei with Z > 92 and N > 140 with a good accuracy, according to which the long-lived SHN should be neutron rich. With Q_alpha values from this formula as inputs, we predict the half-lives of isotopes of Z = 117, which may be useful for experimental identication in the future.Comment: 7 pages, 3 figure

Nuclear isospin asymmetry in α\alpha decays of heavy nuclei

The effects of nuclear isospin asymmetry on $\alpha$ decay lifetimes of heavy nuclei are investigated within various phenomenological models of nuclear potential for the $\alpha$ particle. We consider the widely used simple square well potential and Woods-Saxon potential, and modify them by including an isospin asymmetry term. We then suggest a model for the potential of the $\alpha$ particle motivated by a microscopic phenomenological approach of the Skyrme force model, which naturally introduce the isospin dependent form of the nuclear potential for the $\alpha$ particle. The empirical $\alpha$ decay lifetime formula of Viola and Seaborg is also modified to include isospin asymmetry effects. The obtained $\alpha$ decay half-lives are in good agreement with the experimental data and we find that including the nuclear isospin effects somehow improves the theoretical results for $\alpha$ decay half-lives. The implications of these results are discussed and the predictions on the $\alpha$ decay lifetimes of superheavy elements are also presented.Comment: 14 pages, 7 figures, 7 tables, Accepted by PRC 94, 024320 (2016