Nambu—Jona-Lasinio Model: An Effective Lagrangian for Quantum Chromodynamics at Intermediate Length Scales

Abstract

A Nambu---Jona-Lasinio type model is proposed as an effective Lagrangian for quantum chromodynamics at intermediate length scales. It is shown that the $\mathrm{SU}(n)\ensuremath{\bigotimes}\mathrm{SU}(n)$ non-linear $\ensuremath{\sigma}$ model, including the Wess-Zumino term, can be derived from it in the low-energy limit. Also presented is the effective nonminimal action whose minima correspond to baryons in the many-color limit.