CHARMONIUM CHI-STATES - RADIATIVE AND HADRONIC WIDTHS, SPIN OF THE GLUON

The dipole sum rules, used earlier to give upper and lower bounds for the radiative transitions for χ→γψ and so estimate the hadronic widths of the χ state, are re-examined with more general assumptions about the QQ interaction, namely the presence of spin-spin, spin-orbit, and tensor forces. The lower and upper bounds for a specific J value are now explicitly force dependent. In fact, a useful lower bound can be established only for the J = 2 state. The inferred radiative rates and estimates of hadronic width, based on new data, are similar to those given earlier by the author. The improved presicion of the data affords a test of the spin of the gluon, within conventional QCD assumptions. The inferred ratio of hadronic widths Γh(0++)/Γh(2++) = 5.5+14- 3 is in agreement with the ratio 15:4 expected from spin 1 and in disagreement with the ratio 125:2 for scalar gluons. © 1979.