High-precision half-life determination for Na21 using a 4π gas-proportional counter

Abstract

A high-precision half-life measurement for the superallowed β + transition between the isospin T = 1/2 mirror nuclei 21 Na and 21 Ne has been performed at the TRIUMF-ISAC radioactive ion beam facility yielding T 1/2 = 22.4506(33) s, a result that is a factor of 4 more precise than the previous world-average half-life for 21 Na and represents the single most precisely determined half-life for a transition between mirror nuclei to date. The contribution to the uncertainty in the 21 Na Ft mirror value due to the half-life is now reduced to the level of the nuclearstructure-dependent theoretical corrections, leaving the branching ratio as the dominant experimental uncertainty.

QEC -value determination for Na21→Ne21 and Karthein1, Atanasov2, Blaum3 et al. 2019Phys. Rev. CSelf Cite

“…were calculated using the half-lives t 1/2 and branchingratios BR given in Ref. [47][48][49] and in Ref. [9] for 21 Na and 23 Mg, respectively.…”