Manifestation of Hidden Symmetries in Baryonic Matter: From Finite Nuclei to Neutron Stars

TL;DR

This paper explores hidden symmetries in baryonic matter, linking nuclear and astrophysical phenomena through topology changes and emergent symmetries, providing insights into neutron star cores and nuclear transitions.

Contribution

It introduces a unified framework connecting hadron-quark duality, hidden symmetries, and topological changes to explain properties of dense baryonic matter and neutron stars.

Findings

Emergence of hidden gauge and pseudo-conformal symmetries at high densities.

Description of quasiparticles with fractional baryon charges in neutron star cores.

Explanation of the effective g_A* and sound velocity in dense nuclear matter.

Abstract

The hadron-quark/gluon duality formulated in terms of a topology change at a density $n\gsim 2n_0$ $n_0\simeq 0.16$fm$^{-3}$ is found to describe the core of massive compact stars in terms of quasiparticles of fractional baryon charges, behaving neither like pure baryons nor like deconfined quarks. This can be considered as the Cheshire-Cat mechanism~\cite{CC} for the hadron-quark continuity arrived at bottom-up from skyrmions that is equivalent to the "MIT-bag"-to-skyrmion continuity arrived at top-down from quarks/gluons. Hidden symmetries, both local gauge and pseudo-conformal (or broken scale), emerge and give rise both to the long-standing "effective $g_A^\ast\approx 1$" in nuclear Gamow-Teller transitions at $\lsim n_0$ and to the pseudo-conformal sound velocity $v_{pcs}^2/c^2\approx 1/3$ at $\gsim 3n_0$. It is suggested that what has been referred to, since a long time, as "quenched $g_A$" in light nuclei reflects what leads to the dilaton-limit $g_A^{\rm DL}=1$ at near the (putative) infrared fixed point of scale invariance. These properties are confronted with the recent observations in Gamow-Teller transitions and in astrophysical observations.