Charmonium spectroscopy from inclusive ψ’ and J/ψ radiative decays

Results from a detailed study using the Crystal Ball detector at the SLAC $e^{+}$$e^{\mathrm{-}}$ storage ring SPEAR of the inclusive photon spectra from 1.8×${10}^6$ ψ’ and 2.2×${10}^6$ J/ψ decays are presented. Radiative transitions from the ψ’ to the ${\chi }_2$,1,0 states are observed with photon energies of 126.0±0.2±4, 169.6±0.3±4, and 258.4±0.4±4 MeV and branching ratios B(ψ’→γ${\chi }_2$,1,0) =(8.0±0.5±0.7)%, (9.0±0.5±0.7)%, and (9.9±0.5±0.8)%, respectively. Values for the natural linewidths of the χ states are obtained: Γ(${\chi }_2$,1,0)=0.8–4.9, <3.8, and 13–21 MeV, respectively (90% C.L.). Improved values are found for the branching ratios B(ψ’→γ${\eta }_c$) =(0.28±0.06)% and B(J/ψ→γ${\eta }_c$)=(1.27±0.36)%, and for the natural width Γ(${\eta }_c$)=11.5±4.5 MeV.