Minimal color-flavor-locked–nuclear interface (original) (raw)
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The quark exchange model is a simple realization of an adiabatic approximation to the strong-coupling limit of Quantum Chromodynamics (QCD): the quarks always coalesce into the lowest energy set of flux tubes. Nuclear matter is thus modeled in terms of its quarks. We wish to study the correlations imposed by total wavefunction antisymmetry when color degrees of freedom are included. To begin with, we have considered one-dimensional matter with a SU (2) color internal degree of freedom only. We proceed by constructing a totally antisymmetric, color singlet Ansatz characterized by a variational parameter λ (which describes the length scale over which two quarks in the system are clustered into hadrons) and by performing a variational Monte Carlo calculation of the energy to optimize λ for a fixed density. We calculate the q − q correlation function as well, and discuss the qualitative differences between the system at low and high density.
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We consider strong interactions at finite density in mean field theory, through an effective lagrangian that can describe both nuclear matter and quark matter. This lagrangian has three couplings that are all fixed by experiment and no other parameters. With increasing baryon density we then find the following hierarchy. At nuclear density and above we have nuclear matter with chiral spontaneous symmetry breaking (SSB), followed by the pion condensed quark matter, again with chiral SSB, albeit with a different realization and finally a transition to the diquark CFL state which also has chiral SSB (and colour SSB), with yet another realization. To one's surprise at zero temperature (in mean field theory), at any finite density chiral symmetry is never restored! We find another remarkable feature and this is that the tree level mass of the sigma particle, that is set by experiment to about 800 MeV, has a crucial and unexpected influence on the physics. Strange quark matter and str...
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Exotic States Of Nuclear Matter, 2008
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Accessibility of color superconducting quark matter phases in heavy-ion collisions
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We discuss a hybrid equation of state (EoS) that fulfills constraints for mass-radius relationships and cooling of compact stars. The quark matter EoS is obtained from a Polyakov-loop Nambu-Jona-Lasinio (PNJL) model with color superconductivity, and the hadronic one from a relativistic meanfield (RMF) model with density-dependent couplings (DD-RMF). For the construction of the phase transition regions we employ here for simplicity a Maxwell construction. We present the phase diagram for symmetric matter which exhibits two remarkable features: (1) a "nose"-like structure of the hadronic-to-quark matter phase border with an increase of the critical density at temperatures below T ∼ 150 MeV and (2) a high critical temperature for the border of the two-flavor color superconducting (2SC) phase, T c > 160 MeV. We show the trajectories of heavy-ion collisions in the plane of excitation energy vs. baryon density calculated using the UrQMD code and conjecture that for incident energies of 4. .. 8 A GeV as provided, e.g., by the Nuclotron-M at JINR Dubna or by lowest energies at the future heavy-ion collision experiments CBM@FAIR and NICA@JINR, the color superconducting quark matter phase becomes accessible.