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

TL;DR

This paper measures the ratio of radiative branching fractions for _{cJ} decays to _{J}/J/, providing a precise value that improves upon previous data by reducing systematic uncertainties.

Contribution

It presents a new, more precise measurement of the ratio of _{c1} to _{c2} radiative branching fractions using CLEO data, with reduced systematic uncertainties.

Findings

Ratio of branching fractions: 1.91 b1 0.10

Improved precision over previous measurements

Systematic uncertainties minimized through cancellation

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.