Multifarious roles of hidden chiral-scale symmetry:"Quenching" ${g_A}$ in nuclei

The Non-Quenching of $g_A$ in Nuclei and Emergent Scale Symmetry in Dense Baryonic Matter

How the axial coupling constant $g_A$ in nuclear Gamow-Teller transitions described in shell model gets "quenched" to a universal constant close to 1 can be explained by nuclear correlations in Fermi-liquid fixed point theory using a scale-symmetric chiral Lagrangian supplemented with hidden local symmetric vector mesons. Contrary to what one might naively suspect -- and has been discussed in some circles, there is no fundamental quenching at nuclear matter density due to QCD condensates. When the density of many-body systems treated with the same Lagrangian increases beyond the density $n=n_{…

How and How Much is ${g_A}$ {\it Fundamentally} Quenched in Nuclei?

The superallowed Gamow-Teller transition in the doubly-magic-shell nucleus $^{100}$Sn and the high resolution spectral shape analysis in the fourth-forbidden nonunique transition in $^{115}$In indicate as much as $\sim 40\%$ {\it fundamental} quenching in the axial-current coupling constant $g_A$ in nuclei. This can be attributed to an effect of the trace anomaly in QCD "emerging" in nuclear medium. If confirmed, this would signal a major revamping to do in nuclear interactions consistent with chiral-scale symmetry in nuclear medium and a big impact on $0ν$ and $νν$ double $β$ decays for BSM. …

核物质中由反常导致的 $g_A$ 淬灭及其对寻找无中微子 $ββ$ 衰变的影响

Anomaly-Induced Quenching of ${g_A}$ in Nuclear Matter and Impact on Search for Neutrinoless $ββ$ Decay

本文通过匹配 FLFP 理论与 ESPM，区分 QCD 标度反常导致的 $g_A$ 真正淬灭与核关联效应，并提出利用 $^{100}$Sn 和 $^{115}$In 衰变检验基本淬灭。

核与核物质中的淬灭 ${g_A}$ 难题及 QCD 中的“伪共形性”

The Quenched ${g_A}$ Puzzle in Nuclei & Nuclear Matter and "Pseudo-Conformality" in QCD

本文利用隐藏局域与标度对称手征拉格朗日量的重正化群方法，解决了核中淬灭 $g_A$ 难题，精确重现超容许 Gamow-Teller 跃迁并得到淬灭因子 $q\approx0.78$，揭示了核物质中标度手征对称性及其对核物理第一性原理研究的重要意义。

The "Folk Theorem" on Effective Field Theory: How Does It Fare in Nuclear Physics?

This is a brief history of what I consider as very important, some of which truly seminal, contributions made by young Korean nuclear theorists, mostly graduate students working on PhD thesis in 1990's and early 2000's, to nuclear effective field theory, nowadays heralded as the first-principle approach to nuclear physics. The theoretical framework employed is an effective field theory anchored on a scale-invariant hidden local symmetric Lagrangian constructed along the line of Weinberg's "Folk Theorem" on effective field theory. The problems addressed are the high-precision calculations on th…

A Solution to the Quenched ${g_A}$ Problem in Nuclei and Dense Baryonic Matter

When scale symmetry is combined with chiral symmetry in a scale-chiral Lagrangian, it can be shown in Fermi-liquid fixed point theory that $g_A^{\rm eff}\approx 1$ in finite nuclei {\it as well as} in dense baryonic matter. This is suggested as a signal for emergence of hidden symmetries of QCD in baryonic matter from low to very high density. This calculation throws doubt on the "first principles" explanation of the quenching of $g_A$ in nuclei with two-body meson-exchange currents. It also has relevance to Gamow-Teller matrix elements in neutrinoless double $β$ decay.