Vertex Correction at Finite Temperature and Decoupling Phase Transition in 2+1-Dimensional Chiral Gross-Neveu Model

Abstract：

With the aid of imaginary-time temperature field theory and fermion mass spectrum derived from Ward-Takahashi identities with composite fields, the vertex correction among fermions and σ meson is calculated beyond the leading order in 1/N expansion in 2+1 dimensional chiral Gross-Neveu model. The behavior of the vertex function with temperature and decoupling phase transition are discussed. The critical temperature of decoupling phase transition arises when the fermion mass and the π meson mass at zero temperature increase; the vertex correction resulting from thermal fluctuation will influence the fermion dynamical mass and cannot be ignored at finite temperature.