THIRD SECTOR OF LEE MODEL

We study the third sector of the Lee model. In the present work the model is augmented by a third static source U in addition to N and V, with the coupling UV. In the third sector the processes UVN occur, providing a model enriched with a two-particle channel. Using the methods of dispersion theory, the dynamics are reduced to the solution of a Fredholm integral equation in one variable. A variational principle is given for the equation which yields the elastic scattering amplitude. Diagonalization of the second-sector connected S matrix plays an important part in the analysis. Finally, we discuss the relevance of the results to static models with crossingspecifically, to a three-meson solution of the charged-scalar static theory. © 1968 The American Physical Society.