Isospin relations for four nucleons in a single j shell

We had previously used techniques involving isospin to count the number of states for three identical fermions in a single j shell with total angular momentum I=j. We generalize this to all I, but the main thrust of this work is to consider now a 4-fermion system. As before, one evaluates the eigenvalues of the Hamiltonian \sum_{i<j}[a + bt(i)t(j)] both from an isospin point of view and an angular momentum point of view. In the 4-particle case, we get a more limited result than in the 3-particle case, namely the number of T=0 states minus twice the number of T=2 states, all of a given angular momentum I.Comment: 6 pages, RevTex

Shapes and beta decay in proton rich Ge, Se, Kr and Sr isotopes

We study ground states and beta decay properties of the proton rich isotope chains Ge, Se, Kr, and Sr. We use a deformed selfconsistent HF+RPA approach with density-dependent effective interactions of Skyrme type. We find that most of the isotopes present two HF minima corresponding to two different shapes. In addition to static quadrupole moments and other ground state band properties, we present results for Gamow-Teller strength distributions, as well as for half-lives and summed strengths. The role of deformation is particularly emphasized.Comment: 29 pages Revtex, 19 PS figures, to appear in Nucl. Phys.