Meson-Photon Transition Form Factors in the Charmonium Energy Range

TL;DR

This paper investigates meson-photon transition form factors in the charmonium energy range using electron-positron collision data, providing estimates for processes involving pseudoscalar mesons at various resonance energies.

Contribution

It offers new estimates of continuum processes involving meson-photon transitions at specific charmonium energies, enhancing understanding of these rare events.

Findings

Estimated cross sections for $e^+ e^- o \gamma P$ at $J/$, $(2S)$, and $(3770)$ energies.

Analysis of the contributions from charmonium decays versus continuum processes.

Improved sensitivity in detecting meson-photon final states in electron-positron collisions.

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 $\eta'$ can arise either from charmonium decays or in the continuum through a virtual photon: $e^+ e^- \to \gamma^* \to \gamma P$. 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.