Separation of soft and collinear singularities from one-loop N-point integrals

Abstract

The soft and collinear singularities of general scalar and tensor one-loop N-point integrals are worked out explicitly. As a result a simple explicit formula is given that expresses the singular part in terms of 3-point integrals. Apart from predicting the singularities, this result can be used to transfer singular one-loop integrals from one regularization to another or to subtract soft and collinear singularities from one-loop Feynman diagrams directly in momentum space.