Given a resonance of known mass, width, and JPC, we can determine its gluonic branching fraction bRgg from data on it s production in radiative vector quarkonium decay VR. For most resonances bRgg is found to be 10%, consistent with being qq states, but we find that both pseudoscalars observed in the 1440 MeV region have bRgg1/2-1, and b(f0++g)1/2. As data improve, bRgg should be a useful discriminator between qq and gluonic states and may permit quantitative determination of the extent to which a particular resonance is a mixture of glueball and qq. We also examine the regime of validity of PQCD for predicting the rate of Vg, the extra pseudoscalar bound state which would exist if there were light gluinos. From the CUSB limit on peaks in X, the mass range 3 GeVm(g)7 GeV can be excluded. An experiment must be significantly more sensitive to exclude an g lighter than this.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)