The Mythic E121 Bound-State beta-Decay of Thallium-205 for AstrophysicsONLINE ONLY

The E121 proposal to measure the bound-state beta-decay of 205Tl has been one of the longest running proposals at GSI, with its origins as a foundational motivation for the construction of the ESR. The ground-breaking experiment was realised in March 2020, were the FRS generated up to 100 stacks of fully-stripped 205Tl that was stored in the ESR to determine the half-life of this rare decay mode. The measured half-life deviates significantly from theoretical predictions, and the implications for our understanding of the early solar system and the feasibility of the LOREX neutrino capture experiment are currently being clarified.