[en] The d+d and p+t partial and total reaction cross sections are computed with a multiconfiguration resonating-group method. The model space employed is spanned by p+t, n+h, d+d, and pseudoinelastic configurations involving deuteron pseudoexcited states. The results show that, at energies where the influence of relatively sharp resonance levels is small, the calculated cross sections for the reactions d(d,p)t, d(d,n)h, and p(t,n)h agree well with experiment. On the other hand, it is also found that, for d+d going into three- and four-particle channels, the calculated reaction cross sections are much too small, suggesting that the inclusion of direct-breakup processes alone through the use of deuteron pseudoinelastic configurations is not sufficient. Because of this, we conclude that the model space employed here is still not extensive enough, especially in the channel spin S=2 state, and should be further expanded to include cluster-rearrangement configurations p+t^* and n+h^*, where t^* and h^* represent excited states of the three-nucleon systems having n+d and p+d cluster structures with relative orbital angular momentum I=1 and spin angular momentum S=3/2

[en] F. S. Stephens et al. answer the comments made by C. L. Wu et al. on the quantized spin alignment of superdeformed Hg(mercury) nuclei

[en] A shell-model study is made of first-forbidden β decay in A=205--212 nuclei. A least-squares fit for eighteen ΔJ=0 and 1 decays gave a scaling factor for the rank-one contributions of 0.97±0.06, i.e., agreement with experiment, and an enhancement factor ε_MEC for the rank-zero matrix element of γ₅ of 2.01±0.05, indicating an enhancement by 100% over the impulse approximation. A 40% effect is predicted from meson exchange. Thus, a deficiency in the meson-exchange calculation or some further unforeseen effect is suggested

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[en] The weight function in the general expression of Lipkin (1958 Phys. Rev. 110,1395) for eliminating the centre-of-mass coordinate from nuclear wavefunctions has been approximated by a gaussian function exp(-lambdaR²) with on parameter, lambda, to be determined by a variational calculation. This calculation has been carried out for the ground state of ⁶Li and the lowest energy has been obtained for a negative value of lambda. An explanation for this surprising result based on the cluster model is given. The result is also compared with other proposals in the literature for treating the centre-of-mass motion in nuclei. (author)

[en] We present a semiclassical approach, the partial h resummation method, to calculate nuclear ground state properties in a selfconsistent way starting from an effective nucleon-nucleon interaction. This method is shown to be easily generalized to describe excited nuclear systems. Selfconsistent semiclassical densities can be further used as an optimal starting point for the calculaion of nuclear deformation energy surfaces like fission barriers

[en] The Kuo-Brown realistic dsub(3/2)-fsub(7/2) interaction is compared with several sets of matrix elements extracted from experimental spectra, and with constraints on centroids imposed by a weak-coupling calculation for particle-hole states around mass 40. It is shown that the Kuo-Brown T = 1 interaction is too attractive, whereas the T = 0 interaction is insufficiently attractive by a substantial amount. (orig.)