arXiv subjects
Publications and source records attributed to Pedro Costa.
The behavior of $η$ and $η'$ in hot strange quark matter in weak equilibrium with temperature, is investigated within the SU(3) Nambu-Jona-Lasinio [NJL] model. Possible manifestations of restoration of symmetries, by temperature or density, in the behavior of $η$ and $η'$ are discussed. The role played by the combined effect of temperature and density in the nature of the phase transition and meson behavior is also analyzed.
The behavior of neutral pseudoscalar mesons $π^0, η$ and $η'$ in hot and dense matter is investigated, in the framework of the three flavor Nambu-Jona-Lasinio model. Three different scenarios are considered: zero density and finite temperature, zero temperature and finite density in a flavor asymmetric medium with and without strange valence quarks, and finite temperature and density. The behavior of mesons is analyzed in connection with possible signatures of restoration of symmetries. In the high density region and at zero temperature it is found that the mass of the $η'$ increases, the deviation from the mass of the $η$ being more pronounced in matter without strange valence quarks.
The behavior of kaons and pions in strange quark matter in weak equilibrium, is investigated within the SU(3) Nambu-Jona-Lasinio [NJL] model. This work focuses a region of high densities where the behavior of mesons has not been explored in the framework of this model. It is found that above the density where strange valence quarks appear in the medium, $ρ= 3.8 ρ_0$, a change of behavior of different observables is observed indicating a tendency to the restoration of flavor symmetry. In particular, the splitting between charge multiplets, $K^+, K^-; K^0, {\bar K^0} {and} π^+, π^-$ decrease and the low energy modes with quantum numbers of $K^-, \bar K^0 {and} π^+$, which are excitations of the Fermi sea, are less relevant than for lower densities.