Threshold amplitudes in field theories and integrable systems

Abstract

We discuss the threshold tree amplitudes in diverse nonintegrable quantum field theories in the framework of integrability. The amplitudes are related to some Baker functions defined on the auxiliary spectral curves and the nullification phenomena are shown to allow a topological interpretation.Comment: 8 pages,Latex, ps is available at http://venus.itep.ru/preprints/1995/95061.ps.g