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, 151-155La were measured at the Radioactive Isotope Beam Factory (RIBF) 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.
0