dorsal/arxiv
View SchemaA Schematic Model for $\rho$-$a_1$ Mixing at Finite Density and In-Medium Effective Lagrangian
| Authors | Youngman Kim, R. Rapp, G. E. Brown, Mannque Rho |
|---|---|
| Categories | |
| ArXiv ID | nucl-th/9912061 |
| URL | https://arxiv.org/abs/nucl-th/9912061 |
| DOI | 10.1103/PhysRevC.62.015202 |
| Journal | Phys.Rev. C62 (2000) 015202 |
Abstract
Based on schematic two-level models extended to $a_1$-meson degrees of freedom, we investigate possible mechanisms of chiral restoration in the vector/axialvector 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 $\pi\leftrightarrow [\Delta (1232)N^{-1}]\equiv\hat\pi$, $\rho\leftrightarrow [N^* (1520)N^{-1}]\equiv\hat\rho$, etc.. In a mean-field type treatment the in-medium gauge coupling $\hat g$, the (axial-) vector meson masses and $\hat f_\pi$ 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 axialvector correlators to the pion decay constant. Using in-medium $\rho$/$a_1$ spectral functions (computed in the two-level model) also leads to a substantial reduction of the pion decay constant with increasing density.
{
"annotation_id": "8f614344-e447-4eb5-bcae-ac959ff70939",
"date_created": "2026-03-02T18:00:28.795000Z",
"date_modified": "2026-03-02T18:00:28.795000Z",
"file_hash": "2a0b9a3447fd8a51d6f979fa7f8f276079416a7a661d97b1994eb795e9981806",
"private": false,
"record": {
"abstract": "Based on schematic two-level models extended to $a_1$-meson degrees of\nfreedom, we investigate possible mechanisms of chiral restoration in the\nvector/axialvector channels in cold nuclear matter. In the first part of this\narticle we employ the massive Yang-Mills framework to construct an effective\nchiral Lagrangian based on low-energy mesonic modes at finite density. The\nlatter are identified through nuclear collective excitations of `meson\u0027-sobar\ntype such as $\\pi\\leftrightarrow [\\Delta (1232)N^{-1}]\\equiv\\hat\\pi$,\n$\\rho\\leftrightarrow [N^* (1520)N^{-1}]\\equiv\\hat\\rho$, etc.. In a mean-field\ntype treatment the in-medium gauge coupling $\\hat g$, the (axial-) vector meson\nmasses and $\\hat f_\\pi$ are found to decrease with density indicating the\napproach towards chiral restoration in the language of in-medium effective\nfields. In the second part of our analysis we evaluate the (first) in-medium\nWeinberg sum rule which relates vector and axialvector correlators to the pion\ndecay constant. Using in-medium $\\rho$/$a_1$ spectral functions (computed in\nthe two-level model) also leads to a substantial reduction of the pion decay\nconstant with increasing density.",
"arxiv_id": "nucl-th/9912061",
"authors": [
"Youngman Kim",
"R. Rapp",
"G. E. Brown",
"Mannque Rho"
],
"categories": [
"nucl-th",
"hep-ph"
],
"doi": "10.1103/PhysRevC.62.015202",
"journal_ref": "Phys.Rev. C62 (2000) 015202",
"title": "A Schematic Model for $\\rho$-$a_1$ Mixing at Finite Density and In-Medium Effective Lagrangian",
"url": "https://arxiv.org/abs/nucl-th/9912061"
},
"schema_id": "dorsal/arxiv",
"source": {
"execution_id": "9180bba9-f20b-4a85-8944-140c541f79e1",
"id": "arXiv Dataset IDs",
"type": "Model",
"variant": "snapshot-2026-03-01",
"version": "0.1.0"
},
"user_id": 1000002
}