Schematic model for {rho}-a{sub 1} mixing at finite density and in-medium effective Lagrangian

Journal Article · Sat Jul 01 04:00:00 EDT 2000 · Physical Review. C, Nuclear Physics

DOI:https://doi.org/10.1103/PhysRevC.62.015202· OSTI ID:20216949

Kim, Youngman ^[1]; Rapp, R ^[1]; Brown, G E ^[1]; Rho, Mannque ^[1]

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1. Department of Physics and Astronomy, State University of New York at Stony Brook, Stony Brook, New York 11794-3800 (United States)

Based on schematic two-level models extended to a{sub 1}-meson degrees of freedom, we investigate possible mechanisms of chiral restoration in the vector-axial-vector channels in cold nuclear matter. In the first part of this article we employ the massive Yang-Mills framework to construct an effective chiral Lagrangian based on low-energy mesonic modes at finite density. The latter are identified through nuclear collective excitations of ''meson''-sobar type such as {pi}{r_reversible}[{delta}(1232)N{sup -1}]{identical_to}{pi}, {rho}{r_reversible}[N{sup *}(1520)N{sup -1}]{identical_to}{rho}, etc. In a mean-field type treatment the in-medium gauge coupling g, the (axial-)vector meson masses and f{sub {pi}} are found to decrease with density indicating the approach towards chiral restoration in the language of in-medium effective fields. In the second part of our analysis we evaluate the (first) in-medium Weinberg sum rule which relates vector and axial-vector correlators to the pion decay constant. Using in-medium {rho}/a{sub 1} spectral functions (computed in the two-level model) also leads to a substantial reduction of the pion decay constant with increasing density. (c) 2000 The American Physical Society.

• OSTI ID: 20216949
• Journal Information: Physical Review. C, Nuclear Physics, Journal Name: Physical Review. C, Nuclear Physics Journal Issue: 1 Vol. 62; ISSN 0556-2813; ISSN PRVCAN
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
CHIRAL SYMMETRY
COLLECTIVE EXCITATIONS
DELTA-1232 BARYONS
LAGRANGIAN FIELD THEORY
N-1520 BARYONS
NUCLEAR MATTER
PIONS
THEORETICAL DATA
VECTOR MESONS
YANG-MILLS THEORY