Speaker
Description
Summary
Weak interaction Gamow-Teller (GT) matrix elements are important in various astrophysical scenarios as well as in double-beta decay. The measured values of the GT strength are much lower than predicted in a simple shell model of independent particles. The doubly magic nucleus 100Sn is unique since its large beta-decay energy window enables access to the complete GTGR and the closed shells reduce the effect of ph-correlations. The GT-transition proceeds through the decay of a g9/2 proton to a g7/2 neutron and is predicted to dominantly populate a single 1+ state in 100In for which the amount of quenching is intensively debated.
Recently half-life and Q-value for the GT-decay of 100Sn was measured at GSI-Darmstadt and the smallest log-ft value of any beta-decay and a GT strength of BGT = 9:1 +4.8 -2.3 establishing it as superallowed GT decay.
Using the high intensity beam at the RIBF/BigRIPS facility and a setup very similar to the recent experiment should allow to increase the world statistics of this decay by a factor of 8 and therefore significantly reduce the error bar in the BGT. Especially gamma-gamma coincidences in the daughter nucleus 100In passing to the ground state should allow for a unique definition of its structure. Also hints towards a proton decay of 100 Sn could be verified. In the same experiment also the beta decay of the recently discovered 99Sn will allow to give in comparison a deeper insight to quenching factors and their origins.
