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

Abstract

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 $n=n_{1/2}\gsim 2n_0$ (where $n_0$ is the normal nuclear matter density) at which skyrmions representing baryons fractionize to half-skyrmions, with the $\rho$ meson driven toward the vector manifestation fixed point and a scalar meson $\sigma$ driven to the dilaton-limit fixed point with the nucleons parity-doubled, the dense matter supports the "pseudo-conformal" sound velocity for $n\gsim n_{1/2}$ while the trace of the energy momentum tensor remains non-vanishing. A plausible interpretation is that this signals the emergence of scale symmetry not explicitly present or hidden in QCD in the vacuum. The fundamental constant $g_A$, unaffected by QCD condensates for $n<n_{1/2}$, does go to 1 as the dilaton-limit fixed point is approached before arriving at chiral restoration, but it is not directly related to the "quenched $g_A$" in nuclei which can be explained as a Fermi-liquid fixed point quantity. The mechanism that produces a precocious pseudo-conformal sound velocity is expected to impact on the tidal deformability $\Lambda$ in gravity waves from coalescing neutron stars.

arXiv commentPublished version

References in corpus (32)

• GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral
• Renormalization Group Approach to Interacting Fermions
• From hadrons to quarks in neutron stars: a review
• Status and Future of Nuclear Matrix Elements for Neutrinoless Double-Beta Decay: A Review
• Hidden Local Symmetry at Loop -- A New Perspective of Composite Gauge Boson and Chiral Phase Transition
• Constraining the speed of sound inside neutron stars with chiral effective field theory interactions and observations
• Chiral two-body currents in nuclei: Gamow-Teller transitions and neutrinoless double-beta decay
• Value of the axial-vector coupling strength in $\beta$ and $\beta \beta$ decays: A review
• Parameter-free effective field theory calculation for the solar proton-fusion and hep processes
• Neutron Lifetime and Axial Coupling Connection
• Chiral Dynamics and Heavy-Fermion Formalism in Nuclei: I. Exchange Axial Currents
• Low-energy effective action for pions and a dilatonic meson
• Radiative Neutron-Proton Capture in Effective Chiral Lagrangians
• $\Delta I=1/2$ rule for kaon decays derived from QCD infrared fixed point
• Quantum Monte Carlo calculations of weak transitions in $A$=6--10 nuclei
• Double Decimation and Sliding Vacua in the Nuclear Many-Body System
• Half-Skyrmions, Tensor Forces and Symmetry Energy in Cold Dense Matter
• Scale-Invariant Hidden Local Symmetry, Topology Change and Dense Baryonic Matter II
• Effects of three-nucleon forces and two-body currents on Gamow-Teller strengths
• Shell model description of the 14C dating beta decay with Brown-Rho-scaled NN interactions
• Dilaton-Limit Fixed Point in Hidden Local Symmetric Parity Doublet Model
• From Chiral Lagrangians to Landau Fermi Liquid Theory of Nuclear Matter
• Cheshire Cat Hadrons
• Interplay between ω-Nucleon Interaction and Nucleon Mass in Dense Baryonic Matter
• The Dilated Chiral Quark Model
• Chiral-scale effective theory including a dilatonic meson
• Fluctuations In ``BR-Scaled'' Chiral Lagrangians
• Half-Skyrmions and the Equation of State for Compact-Star Matter
• Nuclear matter with Brown-Rho-scaled Fermi liquid interactions
• Scale-Invariant Hidden Local Symmetry, Topology Change and Dense Baryonic Matter
• Hidden Local Symmetry and Beyond
• Nucleon internal degrees of freedom and the uniqueness of the Gamow-Teller state

Cited by in corpus (5)

• Sound velocity and tidal deformability in compact stars
• The Quenched $g_A$ in Nuclei and Emergent Scale Symmetry in Baryonic Matter
• Topology and emergent symmetries in dense compact star matter
• Axial coupling constant in a magnetic background
• Topology change and emergent scale symmetry in compact star matter via gravitational wave detection