Meson-Photon Transition Form Factors in the Charmonium Energy Range

Abstract

The study of electron-positron collisions at center-of-mass energies corresponding to charmonium production has reached new levels of sensitivity thanks to experiments by the BES and CLEO Collaborations. Final states $\gamma P$, where $P$ is a pseudoscalar meson such as ${\pi }^0$, $\eta$, and ${\eta }^{\prime }$ can arise either from charmonium decays or in the continuum through a virtual photon: $e^{+}{e}^{-}\to {\gamma }^{\ast }\to \gamma P$. Estimates of this latter process are given at center-of-mass (c.m.) energies corresponding to the $J/\psi (1S)$, $\psi (2S)$, and $\psi (3770)$ resonances.

7 pages, to be submitted to Phys. Rev. D. Version referring to new CLEO data