Recently, Phys. Rev. Lett., an internationally renowned physics journal, published online the research result "Quenched

in Nuclei and Emergent Scale Symmetry in Baryonic Matter" by Prof. Ma Yongliang from HIAS, UCAS in China and Prof. Mannque Rho from Paris-Saclay University in France, which proposes a model for achieving scale symmetry in nuclei and nuclear matter.

Over the past four decades, people have wondered why the Gamow-Teller transition in the nuclear shell model requires a quenched

that is multiplied by the axis vector coupling constant

to make

. The standard nuclear beta decay process contains a superallowed transition with zero momentum transfer, it naturally relates

to a certain basic mechanism, rather than the standard nuclear multi-body interaction.

contains an approximately conserved axial-vector current that reminds us of the assumed vector current conservation:

So the question becomes whether

suggests the existence of intrinsic and extrinsic properties that have not been recognized in the currently accepted basic theory of quantum chromodynamics, or it is simply a coincidence due to ordinary strong nuclear correlations, or it is a combination of both. Since Gamow-Teller matrix elements play an important role in the neutrinoless double-beta decay containing non-zero momentum transfers (and therefore not superallowed),the question is important not only for nuclear physics but also for physics beyond the Standard Model.

Ma Yongliang and Mannque Rho find that the recent RIKEN experiment on the quenched gA in the superallowed Gamow-Teller transition from 100Sn indicates the role of scale anomaly encoded in the anomalous dimension β' of the gluonic stress tensor. This observation provides support to the notion of hidden scale symmetry emerging by strong nuclear correlations with an infrared (IR) fixed point realized—in the chiral limit—in the Nambu-Goldstone mode. The paper suggests there is an analogy in the way scale symmetry manifests in a nuclear medium to the continuity from the unitarity limit at low density (in light nuclei) to the dilaton limit at high density (in compact stars). In between the limits, say, at normal nuclear matter density, the symmetry is not visible, hence hidden.

The study was jointly completed by Prof. Ma Yongliang from the HIAS School of Fundamental Physics and Mathematical Sciences and Prof. Mannque Rho from Paris-Saclay University, and was funded by the General Program of the National Natural Science Foundation of China. The HIAS School of Fundamental Physics and Mathematical Sciences and the International Centre for Theoretical Physics Asia-Pacific (ICTP-AP) are the first and second completion units.

Article link: https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.125.142501