Diquarks from aU (3) L ×U (3) R invariant quark Lagrangian

An effective Lagrangian involving composite pseudoscalar and scalar mesons as well as scalar and pseudoscalardiquarks is derived from a chiralU(3) _L ×U(3) _R invariant four-quark theory using path integral methods. We obtain mass relations for the diquarks where all free parameters can be fixed in the meson sector. We also calculate weak diquark decay constants, and discuss baryon masses in terms of a quark-diquark model.