On the manifestation of chiral symmetry in nuclei and dense nuclear matter

This article reviews our view on how chiral symmetry, its pattern of breaking and restoration under extreme conditions manifest themselves in the nucleon, nuclei, nuclear matter and dense hadrome matter. We discuss how first-principle (QCD) calculations of the properties of finite nuclei can be effectuated by embedding the "standard nuclear physics approach (SNPA)" into the framework of effective field theories of nuclei that incorporate chiral dynamics and then exploit the predictive power of the theory to accurately compute such solar neutrino processes as the proton-proton fusion and the "hep" process and such cosmological nueleosynthesis process as thermal neutron-proton capture etc. The Brown-Rho (BR) scaling that implements chiral symmetry property of baryon-rich medium is re-interpreted in terms of "vector manifestation" of hidden local symmetry A la Harada-Yamawaki. We present a clear direct evidence and a variety of indirect evidences for BR scaling in nuclear processes at normal nuclear matter density probed by weak and electromagnetic fields and at higher density probed by heavy-ion collisions and compact-star observables. We develop the notion of "broadband equilibration" in heavy-ion processes and sharpen the role of strangeness in the formation of compact stars and their collapse into black-holes. We revisit the Cheshire Cat phenomenon first discovered in the skyrmion structure of baryons and more recently revived in the form of "quark-hadron continuity" in mapping low-density structure of hadrons to high-density structure of quarks and gluons and argue once more for the usefulness and power of effective field theories based on chiral symmetry under extreme conditions. It is shown how color-flavor locking in terms of QCD variables and hidden local symmetry in terms of hadronic variables can be connected and how BR scaling fits into this "continuity" scheme exhibiting a novel aspect of the Cheshire Cat phenomenon. (C) 2002 Elsevier Science B.V. All rights reserved.