Photon Transitions in ψ(2S) Decays to χ_{cJ}(1P) and η_c(1S)

Abstract

We have studied the inclusive photon spectrum in psi(2S) decays using the CLEO III detector. We present the most precise measurements of electric dipole (E1) photon transition rates for psi(2S)--> gamma chicJ(1P) (J=0,1,2). We also confirm the hindered magnetic dipole (M1) transition, psi(2S)-->gamma etac(1S). However, the direct M1 transition psi(2S)-->gamma etac(2S) observed by the Crystal Ball as a narrow peak at a photon energy of 91 MeV is not found in our data.

8 pages postscript,also available through http://www.lns.cornell.edu/public/CLNS/2004/, submitted to PRL