(2+1)维SU(2)四费米子耦合理论的Ward-Takahashi恒等式和质量谱

Ward-Takahashi Identities and Mass Spectra in(2+1) Dimensional SU(2) Four-fermi Model

本文利用含复合场的Ward-Takahashi恒等式研究了(2+1)维SU(2)四费米子耦合的理论。在SU(2)手征对称性既有明显破缺又有动力学破缺时,得到了动力学所生成的费米子质量和束缚态的谱性质,并讨论了矢量流和轴矢流的性质。结果表明:束缚态π_α获得了质量并得到轴矢流部分守恒的结论;当费米子的流质量较小时,Goldberger-Treiman关系近似成立。

Ward Takahashi identities with composite fields are utilized to investigate (2+1) dimensional model with SU(2) four-fermion couplings. When SU(2) chiral symmetry is both explicitly and dynamically broken, fermion mass is dynamically generated and mass spectra of the bound states are obtained. The properties of vector and axial-vector currents are discussed. It turns out that the bound state π_α acquires a mass and the axial-vector current is partially conserved, and the Goldberger-Treiman relation is approximately valid in the case of small fermion current masses.