A Primer on K-matrix Formalism |version Vii|

A short description is given of the K-matrix formalism. The formalism, which is normally applied to two-body scattering processes, is generalized to production of two-body channels with nal-state interactions. A multi-channel treatment of production of J P C = 0 ++ and J P C = 2 ++ resonances has been worked out in the P-vector approach of Aitchison. An alternative approach, derived from the P-vector, gives the production amplitude as a product of the T-matrix for a two-body system and a vector Q specifying its production. This formulation, dubbed the Q-vector approach in this note, has also been worked out for several examples of practical importance. Two separatèderivations' of the Flatt e formula are given in the K-matrix formalism , and a possible generalization of his formula is also pointed out. In addition, a derivation of David Bugg's formula for two resonances into two channels is given.