Meson-photon transition form factors in the charmonium energy range

The study of electron-positron collisions at center-of-mass (c.m.) 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}{sup 0}, {eta}, and {eta}' can arise either from charmonium decays or in the continuum through a virtual photon: e{sup +}e{sup -}{yields}{gamma}{sup *}{yields}{gamma}P. Estimates of this latter process are given at c.m. energies corresponding to the J/{psi}(1S), {psi}(2S), and {psi}(3770) resonances.