Recent progress in measuring β half-lives of nuclei approaching the r-process waiting point A = 195

Abstract

Heavy neutron-rich nuclei close to N = 126 were produced by fragmentation of a 1 A GeV 208 Pb beam at the FRS at GSI. The β-decay half-lives of 8 nuclides have been determined using a novel numerical analysis method. The comparison of the data with model calculations provides indications on the importance of first-forbidden transitions around A = 195 . The measured data indicate that the matter flow in the r-process to heavier fissioning nuclei may be faster than previously expected.