AuxiliaryMomenta is an option of
FCLoopPropagatorsToLineMomenta,
FCLoopIntegralToGraph and other functions. It specifies
auxiliary momenta that do not correspond to external legs, i.e. don’t
really flow through the lines, e.g. n
and \bar{n} in SCET or v in HQET.
Overview, FCLoopPropagatorsToLineMomenta, FCLoopIntegralToGraph.