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Title: Note on color neutrality in Nambu-Jona-Lasinio-type models

Abstract

By referring to the underlying physics behind the color charge neutrality condition in quark matter, we discuss how this condition should be properly imposed in Nambu-Jona-Lasinio (NJL)-type models in a phenomenologically meaningful way. In particular, we show that the standard assumption regarding the use of two color chemical potentials, chosen in a very special way, is not justified in general. When used uncritically, such an approach leads to wrong or unphysical conclusions.

Authors:
 [1];  [2]
  1. Institut fuer Kernphysik, Technische Universitaet Darmstadt, D-64289 Darmstadt (Germany)
  2. Frankfurt Institute for Advanced Studies, J.W. Goethe-Universitaet, D-60438 Frankfurt (Germany)
Publication Date:
OSTI Identifier:
20713889
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. D, Particles Fields; Journal Volume: 72; Journal Issue: 9; Other Information: DOI: 10.1103/PhysRevD.72.097501; (c) 2005 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; CALCULATION METHODS; COLOR MODEL; POTENTIALS; QUARK MATTER

Citation Formats

Buballa, Michael, and Shovkovy, Igor A. Note on color neutrality in Nambu-Jona-Lasinio-type models. United States: N. p., 2005. Web. doi:10.1103/PhysRevD.72.097501.
Buballa, Michael, & Shovkovy, Igor A. Note on color neutrality in Nambu-Jona-Lasinio-type models. United States. doi:10.1103/PhysRevD.72.097501.
Buballa, Michael, and Shovkovy, Igor A. Tue . "Note on color neutrality in Nambu-Jona-Lasinio-type models". United States. doi:10.1103/PhysRevD.72.097501.
@article{osti_20713889,
title = {Note on color neutrality in Nambu-Jona-Lasinio-type models},
author = {Buballa, Michael and Shovkovy, Igor A.},
abstractNote = {By referring to the underlying physics behind the color charge neutrality condition in quark matter, we discuss how this condition should be properly imposed in Nambu-Jona-Lasinio (NJL)-type models in a phenomenologically meaningful way. In particular, we show that the standard assumption regarding the use of two color chemical potentials, chosen in a very special way, is not justified in general. When used uncritically, such an approach leads to wrong or unphysical conclusions.},
doi = {10.1103/PhysRevD.72.097501},
journal = {Physical Review. D, Particles Fields},
number = 9,
volume = 72,
place = {United States},
year = {Tue Nov 01 00:00:00 EST 2005},
month = {Tue Nov 01 00:00:00 EST 2005}
}
  • We study how the charge neutrality affects the phase structure of the three-flavor Polyakov-loop Nambu-Jona-Lasinio (PNJL) model. We point out that, within the conventional PNJL model at finite density, the color neutrality is missing because the Wilson line serves as an external colored field coupled to dynamical quarks. In this paper we heuristically assume that the model may still be applicable. To get color neutrality, one has then to allow nonvanishing color chemical potentials. We study how the quark matter phase diagram in (T,m{sub s}{sup 2}/{mu})-plane is affected by imposing neutrality and by including the Polyakov-loop dynamics. Although these twomore » effects are correlated in a nonlinear way, the impact of the Polyakov loop turns out to be significant in the T direction, while imposing neutrality brings a remarkable effect in the m{sub s}{sup 2}/{mu} direction. In particular, we find a novel unlocking transition, when the temperature is increased, even in the chiral SU(3) limit. We clarify how and why this is possible once the dynamics of the colored Polyakov loop is taken into account. Also we succeed in giving an analytic expression for T{sub c} for the transition from two-flavor pairing (2SC) to unpaired quark matter in the presence of the Polyakov loop.« less
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  • We study the phase diagram and the pion modes in the electrically neutral two flavor Polyakov-Nambu-Jona-Lasinio model. One of the main results of this paper is that in the model with massive quarks, when electrical neutrality is required, pions do not condense in the ground state of the model: the isospin chemical potential {mu}{sub I}=-{mu}{sub e}/2 is always smaller than the value required for pion condensation to occur. Moreover we investigate on the pions and {sigma} mass spectra. We find that the qualitative behavior of the masses resembles that obtained in the Nambu-Jona-Lasinio model. We close this paper by studyingmore » the intriguing possibility that bound states with the quantum numbers of the pions can be formed above the chiral phase transition.« less
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