β-decay half-lives of 55 neutron-rich isotopes beyond the N = 82 shell gap

Abstract

The β-decay half-lives of 55 neutron-rich nuclei 134−139Sn, 134−142Sb, 137−144Te, 140−146I, 142−148Xe, 145−151Cs, 148−153Ba, and 151−155La were measured at the Radioactive Isotope Beam Factory employing the projectile fission fragments of 238U. The nuclear level structure, which relates to deformation, has a large effect on the half-lives. The impact of newly measured half-lives on modeling the astrophysical origin of the heavy elements is studied in the context of r process nucleosynthesis. For a wide variety of astrophysical conditions, including those in which fission recycling occurs, the half-lives have an important local impact on the second (A ≈ 130) peak.