Quadratic relations between Feynman integrals

Abstract

Feynman integrals come in two varieties: polylogarithmic, or not. They are used in two ways: as contributions to an amplitude that is squared, or as contributions to an observable matrix element. In the former case, products of integrals occur, in the latter they do not. We report on products of non-polylogarithmic Feynman integrals related to the magnetic moment of the electron, giving details of an infinite set of quadratic relations between these integrals at all loops $L>2$.