Radiative decay of Υ into a scalar glueball -: art. no. 074015

We study the radiative decay of Y into a scalar glueball Y-->gammaG(s) using QCD factorization. We find that for this process the nonperturbative effects can be factorized into a matrix element well defined in nonrelativistic QCD (NRQCD) and the gluon distribution amplitude. The same NRQCD matrix element appears also in the leptonic decay of Y and therefore can be determined from data. In the asymptotic limit the gluon distribution amplitude is known up to a normalization constant. Using a QCD sum-rule calculation for the normalization constant, we obtain Br(Y-->gammaG(s)) to be in the range (1-2)x10(-3). We also discuss some of the implications for Y-->gammaf(i) decays. Near future data from CLEO-III can provide crucial information about scalar glueball properties.