Spontaneous generation of Nambu-Jona-Lasinio interaction in QCD involving two light quarks.

Within QCD involving two light quarks, the possibility of a spontaneous generation of effective interaction leading to Nambu-Jona-Lasinio model is studied by using the Bogolyubov quasiaverage approach. The compensation equation for the form factor of this interaction is shown to have a nontrivial solution that leads to a theory involving two parameters: the average value of the low-energy constant α s and a dimensional parameter f π. All of the remaining parameters, including the current and constituent quark masses, the quark condensate, the pion mass, and the sigma-meson mass and width, are expressed in terms of the input parameters in satisfactory agreement with experimental phenomenology. The results obtained here give sufficient grounds to conclude that the proposed approach is applicable in low-energy hadron physics and that it can be used in dealing with other problems. [ABSTRACT FROM AUTHOR]