Events in which the charmonium states $\frac{J}{\psi }$ and ${\psi }^{\prime }$ are produced in 225-GeV/c ${\pi }^{-}$ Be collisions have been selected with a dimuon trigger. Coincidences with detected photons have identified radiative decays from the charmonium $P$ states ($\chi$) to the $\frac{J}{\psi }$. The fraction of $\frac{J}{\psi }$'s resulting from such decays is determined to be 0.37±0.09.

• Received 28 February 1984

DOI:https://doi.org/10.1103/PhysRevD.30.671