On the low energy limit of one loop photon-graviton amplitudes

none4siWe present first results of a systematic study of the structure of the low energy limit of the one-loop photon-graviton amplitudes induced by massive scalars and spinors. Our main objective is the search of KLT-type relations where effectively two photons merge into a graviton. We find such a relation at the graviton-photon-photon level. We also derive the diffeomorphism Ward identity for the 1PI one graviton - N photon amplitudes.noneF. Bastianelli; O. Corradini; J.M. Davila; C. SchubertF. Bastianelli; O. Corradini; J.M. Davila; C. Schuber