Subleading hadronic vacuum polarization contributions to muon $g-2$: ${\mu }^{+}{\mu }^{-}\to {\gamma }^{\ast }\to {\pi }^0{\gamma }^{\ast }$

Abstract

We consider the subleading contributions of the hadronic vacuum polarization, involving the ${\pi }^0{\gamma }^{\ast }{\gamma }^{\ast }$ transition form factor, to the muon anomalous magnetic moment $g-2$. Various models for the form factor, based on hadronic ansatzes and holographic principles, are considered: They are the Wess-Zumino-Witten, vector meson dominance, lowest meson dominance (one and two vector resonances) models, and AdS/QCD. The model parameters are determined by fitting the experimental data for the $e^{+}{e}^{-}\to {\pi }^0\gamma$ total cross section. We report numerical results of the corrections to the muon $g-2$ that the resulting values of two vector resonances model are of order-of-magntitude smaller than the one obtained from the dispersion relation.

Comments: published version, 15 pages, 6 figures, 2 tables