Volume II LECTURES ON THE S-MATRIX THEORY Lecture IX:Singularities Required by Unitarity

摘要

Until now very little about the details of the analyticity properties has been needed. But we have not done very much. Only the general structure of the theory has been set up, no practical problems have been tackled. In order to apply the theory to practical problems one needs a more detailed knowledge of the analytic structure of the M functions.nThe basic idea behind the S-matrix approach to analyticity properties is that certain singularities are required by the unitarity relations. So let me explain what is meant by this.