Kite diagram through symmetries of Feynman integrals

The symmetries of Feynman integrals (SFI) is a method for evaluating Feynman integrals which exposes a novel continuous group associated with the diagram which depends only on its topology and acts on its parameters. Using this method, we study the kite diagram, a two-loop diagram with two external legs, with arbitrary masses and spacetime dimension. Generically, this method reduces a Feynman integral into a line integral over simpler diagrams. We identify a locus in parameter space where the integral further reduces to a mere linear combination of simpler diagrams, thereby maximally generalizing the known massless case.