Charmonium Spectroscopy from Inclusive Photons in J/psi and psi' Decays

摘要

Comparing our precise measurements for the E1 transitions psi' implies gamma chi/sub J/ with theory has underscored the importance of including (i) spin and relativistic corrections, (ii) variations in the 2P and 1S wave function shapes resulting from corrections, and (iii) coupling to closed and open decay channels. Considering our best measured total widths, i.e., GAMMA/sub tot/(eta/sub c) and GAMMA/sub tot(chi/sub o/), it appears that higher order QCD corrections are important and large. Our measurements for the E1 rates chi/sub J/ implies gamma J/sub psi/ suffer from the large errors in GAMMA/sub tot/(chi/sub J/); our best value is for GAMMA(chi/sub o/ implies gamma J/psi), and the agreement here is slightly better with the corrected theories. Both the potential models and the lowest order QCD derived predictions are capable of consistency with our observed HFS, although QCD radiative corrections appear to go in the wrong direction (less splitting than measured). For the best measured M1 allowed pseudoscalar transition, J/psi implies gamma eta/sub c/, the naive potential model and dispersion theory predictions are roughly a factor of 2 large. Perhaps corrections to the M1 formula are important. (ERA citation 07:045035)