EXTENDED NAMBN-JONA-LASINIO MODEL AND HIDDEN LOCAL SYMMETRY OF LOW-ENERGY QCD

Using the standard auxiliary field method, we derive from the extended Nambu-Jona-Lasinio model an effective meson action containing vector and axial-vector mesons in addition to Goldstone bosons. The vector an d axial-vector mesons in this effective action transform as gauge fiel ds of hidden local symmetry G(local) = [U(n)(L) X U(n)(R)](local). Her e, the realization of enlarged hidden local symmetry is accomplished v ia the introduction of two kinds of ''compensating'' fields. For obtai ning the intrinsic-parity-violating part of the action, we generalize the standard gauged Wess-Zumino-Witten action such that it also contai ns two kinds of ''compensators'' in addition to the usual Goldstone bo sons as well as the:vector and axial-vector mesons. This generalized g auged Wess-Zumino-Witten action turns out to have G(global) X G(local) symmetry, where G(global) is the usual U(n)(L) X U(n)(R) global chira l symmetry while G(local) is the U(n)(L) X U(n)(R) hidden local symmet ry. This means that G(local) has no gauge anomaly and its associated v ector and axial-vector mesons can be regarded as gauge bosons of G(loc al). The introduction of the coupling with the external electroweak fi elds requires us to gauge some appropriate subgroup of G(global). To m ake it consistent with the anomaly structure of QCD is a nontrivial pr oblem. We explain how this can be done, following the recent suggestio n by several authors.