New Decay Modes
In an experimental tour de force, live digital photography of di-proton emission from the ground state of the extremely neutron-deficient nucleus 45Fe has been achieved, demonstrating this exotic decay mode unambiguously and clarifying its nature. Near the doubly magic neutron-deficient nucleus 100Sn, where protons and neutrons occupy the same shell model orbits, the fastest known alpha decay was discovered. Together with the discovery of the gamma ray depopulating the first excited state of 101Sn, these measurements are the first steps to determine the shell structure of extremely neutron-deficient heavy nuclei in a region that also represents the possible endpoint of the astrophysical rapid proton capture process powering X-ray bursts. In connection with Penning Trap precision mass measurements of neutron-deficient unstable nuclei in the critical mass 64–72 region, this has led to an impressive reduction in the nuclear physics uncertainty in advanced X-ray burst models which now include all relevant nuclear reactions.
Credit: Miernik et al., Phys. Rev. Lett. 99, 192501 (2007)