Abstract
The reaction has been analyzed using 97 of data taken with the Crystal Ball detector at the DESY storage ring DORIS II at beam energies around 5.3 GeV. For the first time we have measured the cross section for for mvariant masses ranging from threshold to about 2 GeV. We measure an approximately flat cross section of about 10 nb for GeV, which is below 0.6 GeV, in good agreement with a theoretical prediction based on an unitarized Born-term model. At higher invariant masses we observe formation of the resonance and a hint of the . We deduce the following two-photon widths: keV and keV at 90% C.L. The decay-angular distributions show the system to be dominantly spin 0 for GeV and spin 2, helicity 2 in the region, with helicity 0 contributing at most 22% (90% C.L.).
- Received 9 February 1990
DOI:https://doi.org/10.1103/PhysRevD.41.3324
©1990 American Physical Society