Zhuang Peng-Fei

Sigma Decay at Finite Temperature and Density

Sigma decay and its relation with chiral phase transition are discussed at finite temperature and density in the framework of the Nambu-Jona-Lasinio model. The decay rate for the process σ→2π to first order in 1/Nc (inverse number of colours) expansion is calculated as a function of temperature T and baryon density nb. In particular, only when the chiral phase transition happens around the tricritical point, the σ decay results in a non-thermal enhancement of pions in the final state distributions in relativistic heavy ion collisions.Sigma decay and its relation with chiral phase transition are discussed at finite temperature and density in the framework of the Nambu-Jona-Lasinio model. The decay rate for the process sigma ->2 pions to first order in a 1/N_c expansion is calculated as a function of temperature T and baryon density n_b. In particular, only when the chiral phase transition happens around the tricritical point, the sigma decay results in a non-thermal enhancement of pions in the final state distributions in relativistic heavy ion collisions.

Nucleon Mass Splitting at Finite Isospin Chemical Potential

We investigate nucleon mass splitting at finite isospin chemical potential in the frame of two flavor Nambu--Jona-Lasinio model. It is analytically proved that, in the phase with explicit isospin symmetry breaking the proton mass decreases and the neutron mass increases linearly in the isospin chemical potential.We investigate nucleon mass splitting at finite isospin chemical potential in the frame of the two-flavour Nambu-Jona-Lasinio model. It is analytically proven that in the phase with explicit isospin symmetry breaking, the proton mass decreases and the neutron mass increases linearly in the isospin chemical potential.

Magnetic Stability Analysis for Abelian and Non-Abelian Superconductors

We investigate the origin of Abelian and non-Abelian type magnetic instabilities induced by the Fermi surface mismatch between the two pairing fermions in a nonrelativistic model. The Abelian type instability occurs only in a gapless state and the Meissner mass squared becomes divergent at the gapless-gapped transition point, while the non-Abelian type instability happens in both gapless and gapped states and the divergence vanishes. The non-Abelian type instability can be cured in a strong coupling region.

Meson Effects on the Chiral Condensate at Finite Density

Meson corrections on the chiral condensate up to next-to-leading order in a 1/Nc expansion at finite densityare investigated in the NJL model with explicit chiral symmetry breaking. Compared with mean-field results, the chiralphase transition is still of the first order while the properties near the critical density for chiral phase transition are foundto change significantly.

Massive meson fluctuation in NJL model

Based on the self-consistent scheme beyond mean-field approximation in the large

Dissociation Temperature of Strictly Confined Charmonium States

N_c

Possible Instability of the Ground State of Two-Flavour Colour Superconductor Induced by Colour Neutrality

expansion, including current quark mass explicitly, a general scheme of SU(2) NJL model is developed. To ensure the quark self-energy expanded in the proper order of

Formation Region and Amplitude of Colour Superconductivity in an Instanton-Induced Model

N_c

Massive quark propagator in the colour-superconducting phase

, an approximate internal meson propagator is deduced, which is in order of

Meson-Nucleon Scatterings in an SU(3) × SU(3) σ Model*

O(1/N_c)