Large-N Weinberg-Tomozawa interaction and spin-flavor symmetry.

The construction of an extended version of the Weinberg-Tomozawa Lagrangian, in which baryons and mesons form spin-flavor multiplets, is reviewed and some of its properties discussed, for an arbitrary number of colors and flavors. The coefficient tables of spin-flavor irreducible representations related by crossing between the s-, t- and u-channels are explicitly constructed. [ABSTRACT FROM AUTHOR]