Using the CLEO-II detector at the CESR $e~+e~-$ storage ring running at the center-of-mass energy around 10.6 GeV, we have studied exclusive production of charmonium states in two-photon collisions. Employing a dataset comprising 3.0 ${\rm fb}~{-1}$ we have searched for decays of the $\eta_c$, $\chi_{c0}$ and $\chi_{c2}$ mesons resulting in four charged hadrons. We report on the measurements of the cross sections and two-photon widths of these charmonium states.
The first two errors quoted are statistical and systematic,respectively. The third one arises from the uncertainties in the branching ratios of charmed mesons.
The CLEO II detector is used to search for the production of χc2 states in two-photon interactions. We use the signature χc2→γJ/ψ→γl+l− with l=e,μ. Using 1.49 fb−1 of data taken with beam energies near 5.29 GeV, the two-photon width of the χc2 is determined to be Γ(χc2→γγ)=1.08±0.30(stat)±0.26(syst) keV, in agreement with predictions from perturbative QCD.
Results below were obtained usign J/psi from-factors in the two photon propogators, and assumes that only transversely polarized photons are significant inthe production of the CHI/C2(1P) state.
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