An Infra-Red Fixed-Point in QCD with a Dilaton in Nuclear Dynamics

The possible consequence of an IR fixed point in QCD for Nf=2, 3 in nuclear matter is discussed. It is shown in terms of d(ilaton)-χ effective field theory (dχEFT) incorporated in a generalized effective field theory (GnEFT) implemented with hidden local symmetry and hidden scale symmetry that the recently measured superallowed Gamow-Teller transition in the doubly-magic-shell nucleus ¹⁰⁰Sn indicates a surprisingly large anomaly-induced quenching (AIQ) of gA from the free-space value of 1.276 to ≈ 0.8. Combined with the quenching expected from strong nuclear correlations, the effective coupling in nuclei, gAᵉᶠᶠ would come to ~ 1/2. If this result were reconfirmed, it would impact not only nuclear structure and dense compact-star matter -- where gA figures in π-N coupling via the Goldberger-Treiman relation -- but also in search for physics Beyond the Standard Model (BSM), e.g. 0νββ decay, where 4th power of gA figures.