MIXING OF ETA,ETA-' WITH CCBAR,BBBAR STATES AND THEIR RADIATIVE DECAYS

We relate the mixing of η, η′ with cc, bb states to the gluonic matrix elements αs〈0|GG|η(η′)〉 whose expressions are derived on the basis of chiral and large Nc approach. QCD sum rules are used to estimate coupling constants for cc and bb pseudoscalar resonances, which have not yet been observed. The mixing angles are found to be ληηc = -4.6 × 10-3, λη′ηc = -1.2 × 10-2, ληηb = -2.2 × 10-4, λη′ηb = -5.7 × 10-4, etc. Rates of radiative decays into η, η′ for cc, bb states are calculated by using the mixing mechanism and the branching ratios are found to be BR(J/ψ → γη) = 0.061%, BR(J/ψ → γη′) = 0.35%, BR(Υ{hooked} → γη) = 1 × 10-5, BR(Υ{hooked} → γη′) = 6 × 10-5, BR(Υ{hooked}′ → γη) = 5 × 10-6, BR(Υ{hooked}′ → γη′) = 3 × 10-5, etc. © 1990.