Hadronic Light by Light Corrections to the Muon Anomalous Magnetic Moment

Abstract

We review the Hadronic Light-by-Light (HLbL) contribution to the muon anomalous magnetic moment. Upcoming measurements will reduce the experimental uncertainty of this precision observable by a factor of four, thus breaking the current balance with the theoretical prediction. A necessary step to restore it is to decrease the HLbL contribution error, which implies a study of the high-energy intermediate states that are neglected in dispersive estimates. We focus on the maximally symmetric high-energy regime and in quark loop approximation of perturbation theory we check the kinematic-singularity/zero-free tensor decomposition of the HLbL amplitude.