NJL-model analysis of dense quark matter

By M. Buballa. 2004

752 citations recorded by the source corpus.

Abstract Investigations of deconfined quark matter within NJL-type models are reviewed, focusing on the regime of low temperatures and “moderate” densities, which is not accessible by perturbative QCD. Central issue is the interplay between chiral symmetry restoration and the formation of color superconducting phases. In order to lay a solid ground for this analysis, we begin with a rather detailed discussion of two- and three-flavor NJL models and their phase structure, neglecting the possibility of diquark pairing in a first step. An important aspect of this part is a comparison with the MIT bag model. The NJL model is also applied to investigate the possibility of absolutely stable strange quark matter. In the next step the formalism is extended to include diquark condensates. We discuss the role and mutual influence of several conventional and less conventional quark–antiquark and diquark condensates. As a particularly interesting example, we analyze a spin-1 diquark condensate as a possible pairing channel for those quarks which are left over from the standard spin-0 condensate. For three-flavor systems, we find that a self-consistent calculation of the strange quark mass, together with the diquark condensates, is crucial for a realistic description of the 2SC–CFL phase transition. We also study the effect of neutrality constraints which are of relevance for compact stars. Both, homogeneous and mixed, neutral phases are constructed. Although neutrality constraints generally tend to disfavor the 2SC phase we find that this phase is again stabilized by the large values of the dynamical strange quark mass which follow from the self-consistent treatment. Finally, we combine our solutions with existing hadronic equations of state to investigate the existence of quark matter cores in neutron stars.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/6c37216efdc92046d9b25b75fe833bf594411d69

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Citations in the corpus

New Neutron Star Equation of State with Quark–Hadron Crossover (2019, background): “Buballa (2005)), in which gluon degrees of freedom are taken into account only implicitly.”
QCD at finite temperature and chemical potential from Dyson–Schwinger equations (2018, result): “e interior of neutron stars to explore the phase boundary between the CFL and the 2SC states. This has been one of the main points of the studies in the DSE approach. In contrast to NJL-model studies [51], the early DSE calculations indicated that the CFL phase is dominant for chemical potentials do”