Showing papers by "Jens H. Gundlach published in 1995"

Erratum: Radiative decays of the 16.6 and 16.9 MeV states in 8Be and tests of the conservation of the vector current in the A=8 multiplet

Abstract: We measured the $^{4}\mathrm{He}$(\ensuremath{\alpha},\ensuremath{\gamma}) cross section at ${\mathrm{\ensuremath{\theta}}}_{\ensuremath{\gamma}}$=90\ifmmode^\circ\else\textdegree\fi{} across the 16.6 and 16.9 MeV resonances in $^{8}\mathrm{Be}$ and obtained angular distributions on the peaks of both resonances. The decays of the 16 MeV doublet to the 3.0 MeV ${2}^{+}$ final state have an (isovector E2)/(isovector M1) mixing ratio of (0.01\ifmmode\pm\else\textpm\fi{}0.03), an (isoscalar E2)/(isovector M1) mixing ratio of (0.21\ifmmode\pm\else\textpm\fi{}0.04), and an isovector M1 width of (2.80\ifmmode\pm\else\textpm\fi{}0.18) eV. Our result for the isovector E2 strength disagrees markedly with previous work. We observe ground-state E2 decays of both members of the doublet. We use our results, plus existing $^{8}\mathrm{Li}$ and $^{8}\mathrm{B}$ \ensuremath{\beta}-decay data, to test the conservation of the vector current and to constrain the second-class induced-tensor form factor. Finally, we compare our results to shell-model calculations.