Dipion decay modes of theΥfamily from a universalεcoupling

Abstract

In the framework of a universal-E-coupling scheme we obtain predictions for the decay rates of Y'-+Ymr, Y"-+Yz-r, and Y1'-+Y'n-r in agreement with CLEO and CUSB measurements. We also predict the shape of the dipion mass distribution for these transitions. The shape predicted for Y 1 -f i a is found to be in excellent agreement with experiment.