Perturbative approach to U_A(1) breaking

Abstract

The six-quark instanton induced 't Hooft interaction is considered in combination with the Nambu-Jona-Lasinio (NJL) type U_L(3)X U_R(3) chiral symmetric Lagrangian. We discuss the bosonization of this multi-quark interaction, taking the U_A(1) breaking as a perturbation. We discuss its relation with the usual approach.

Comments: LaTeX, 9 pages, Prepared for the Proceedings of The International Conference on High Energy and Mathematical Physics, Marrakech, Morocco, 4-7 April 2005