Finiteness of gravitational corrections to magnetic moments and supergravity embedding

Abstract

We calculate the one-loop O(κ^2) contribution to the anomalous magnetic moment of a lepton in the framework of N = 1 supergravity coupled to super-QED with a charged massive scalar multiplet source, using both supersymmetry violating and preserving regularizations. Since a Pauli term is forbidden by supersymmetry, the ordinary gravity plus QED contribution must be just the negative of that given by the new supersymmetry diagrams in the latter scheme. In particular, the infinite part of the new terms' contribution vanishes; the reason for this is traced to an effective chiral-dual symmetry of our sector. Thus, the "miracle" of the moment's finiteness in ordinary gravity is accounted by supergravity embedding. The significance and implications of regularization ambiguities are also discussed.

Additional details