Ratio of Branching Fractions for $\chi_{cJ} \to \gamma J/\psi$

Abstract

One important quarkonia result from the Tevatron experiments is the ratio of direct inclusive production of \chi_{c1} to \chi_{c2}, which is most readily measured using \chi_{cJ}\to\gamma J/\psi decays. This note uses CLEO publications to obtain a ratio of these radiative branching fractions, {\cal B}(\chi_{c1}\to\gamma J/\psi)/{\cal B}(\chi_{c2}\to\gamma J/\psi) = 1.91 \pm 0.10, using cancelation in systematic uncertainties not available in the Particle Data Group listings.