Probing for an IR-fixed Point in QCD by Superallowed Gamow-Teller Transitions in Doubly Magic Nuclei

This brief note is to point out that the recent measurements at GSI and RIKEN of the superallowed Gamow-Teller transition in the doubly magic closed-shell nucleus ${}^{100}$Sn could give an indication for a possibly important {\it fundamental} quenching, thus-far unrecognized, of $g_A$, unambiguously distinct from nuclear correlation effects in the framework of nuclear effective field theory. The result, either confirmed or ruled out both experimentally and theory, can have strong impacts on nuclear physics vis-à-vis with nuclear effective field theory as well as on particle physics relevant for going beyond the Standard Model.