Photon transitions in Upsilon(2S) and Upsilon(3S) decays

Abstract

We have studied the inclusive photon spectra in Y(2S) and Y(3S) decays using a large statistics data sample obtained with the CLEO III detector. We present the most precise measurements of electric dipole (E1) photon transition rates and photon energies for Y(2S)-->gammachi(bJ)(1P) and Y(3S)-->gammachi(bJ)(2P) (J=0, 1, 2). We measure the rate for a rare E1 transition Y(3S)-->gammachi(b0)(1P) for the first time. We also set upper limits on the rates for the hindered magnetic dipole (M1) transitions to the eta(b)(1S) and eta(b)(2S) states.