Electroweak corrections to $e^{+}{e}^{-}\to \gamma \gamma$ as a luminosity process at FCC-ee

Abstract

We consider large-angle two photon production in $e^{+}{e}^{-}$ annihilation as a possible process to monitor the luminosity of a future $e^{+}{e}^{-}$ circular collider (FCC-ee). We review and assess the status of the theoretical accuracy by performing a detailed phenomenological study of next-to-leading order electroweak corrections and leading logarithmic QED contributions due to multiple photon radiation. We also estimate the impact of photonic and fermion-loop corrections at next-to-next-to-leading order and the uncertainty induced by the hadronic contribution to the vacuum polarization. Possible perspectives to address the target theoretical accuracy are briefly discussed.

Comments: 13 pages, 3 figures, 3 tables. Extended version, with theoretical details and further numerical results, of the contribution to the workshop proceedings arXiv:1905.05078 by the same authors. v2: minor text modification, one reference added