Observation of chi_cJ radiative decays to light vector mesons

TL;DR

This study reports the observation of specific radiative decay modes of chi_cJ charmonium states to light vector mesons using CLEO-c data, providing measurements of branching fractions and polarization states.

Contribution

First observation of chi_c1 decays to gamma rho^0 and gamma omega with measured branching fractions and polarization, along with upper limits for other chi_cJ decays.

Findings

Observed chi_c1 -> gamma rho^0 and gamma omega decays.

Measured branching fractions for these decays.

Determined polarization of the rho^0 meson.

Abstract

Using a total of 2.74 x 10^7 decays of the psi(2S) collected with the CLEO-c detector, we present a study of chi_cJ -> gamma V, where V = rho^0, omega, phi. The transitions chi_c1 -> gamma rho^0 and chi_c1 -> gamma omega are observed with B(chi_c1 -> gamma rho^0) = (2.43 +- 0.19 +- 0.22) x 10^-4 and B(chi_c1 -> gamma omega) = (8.3 +- 1.5 +- 1.2) x 10^-5. In the chi_c1 -> gamma rho^0 transition, the final state meson is dominantly longitudinally polarized. Upper limits on the branching fractions of other chi_cJ states to light vector mesons are presented.