The quantum chromodynamics (QCD) of charmonium system was studied by analyzing two-photon production of C-even charmonium states. Two-photon crossection was measured to determine the two-photon width. Perturbative QCD (PQCD) calculated two-gluon width with reduced uncertainities due to cancellation of charmed quark mass factors, nonperturbative factors and wave function dependence. The cross sections were calculated by dividing the fitted event yield with detection efficiency, integrated luminosity and branching function. The analysis suggested that PQCD calculations accurately predicted the ratios of decay rates.
|Original language||English (US)|
|Number of pages||5|
|Journal||Physical review letters|
|State||Published - Aug 6 2001|