ASYMPTOTIC PHOTON PROPAGATOR IN MASSIVE QED AND THE MUON ANOMALOUS MAGNETIC-MOMENT

Recently, Faustov et al. have obtained, by a renormalization group technique, the asymptotic contribution to the muon anomalous magnetic moment arising from the eight-order diagrams two electron vacuum-polarization loops, one within the other. Their result disagrees strongly with the value previously obtained by numerical evaluation of exact eight-order integrals. We have identified the cause of this discrepancy to be an incorrect four-loop Callan-Symanzik-beta-function. Using the corrected-beta-function, which takes the effect of finite electron mass into account, we find that the result of Faustov et al. agrees very well with that of numerical integration.