On the two-photon contributions to $e^+e^-\toηγ$ and $e^+e^-\toη^\primeγ$
Abstract
Description
Motivated by recent BABAR measurements of the $γ^*\toγη$ and $γ^*\toγη^\prime $ transition form factors, we estimate two-photon exchange contributions to the corresponding cross sections. By using a phenomenological model, based on the vector meson dominance, it is argued that the expected contributions are small enough not to effect the BABAR results. As a by product we predict $Br(η^\prime\toμ^+μ^-)= (1.4\pm 0.2)\times 10^{-7}$. Our results might be useful also in high precision calculations of radiative corrections to the Dalitz decays of pseudoscalar mesons.
23 pages, LaTeX, needs FEYNMAN package
23 pages, LaTeX, needs FEYNMAN package