PREDICTIONS IN THE PSEUDOSCALAR CHANNEL OF CHARMONIUM BY MEANS OF QCDSUM-RULES

We use QCD sum rules for predicting the mass of the eta'(c) resonance and the partial decay width into two gammas of the eta(c) resonance, w hich are poorly known experimentally. To this end we elaborate two num erical algorithms. The former one allows us to extract the mass of the ground state in a given channel of charmonium, if some parameters are known, and the mass of the first excited state, if the mass of the gr ound state and the coupling constant g1 of the ground state to the pro per quark current are known. The algorithm is applied to the vector ch annel for determining one free parameter which is common to all channe ls; moreover, closely examining the relation between g1 and the mass o f the first excited state in that channel suggests a second algorithm for determining g1. Applying these algorithms to the pseudoscalar chan nel leads us to predicting m(eta'c) = 3575(-48)+30 MeV and GAMMA(eta(c ) --> gammagamma) = 5585(-635)+490 eV, in good agreement with other pr edictions and with presently available data.