Inclusive J/ψProduction In ΥDecay Via Color-singlet Mechanism

Abstract

We reconsider the tree level color-singlet contribution for the inclusive J/ψproduction in Υdecay with the α_{s}^{5} order QCD process Υ\to J/ψ+c\bar{c}+g and α^{2}α_s^{2} order QED processes Υ\toγ^{\ast}\to J/ψ+c\bar{c} and Υ\to J/ψ+gg. It is found that the contribution of the QED process is compatible with that of the QCD process, and the numerical results for the QCD process alone is an order of magnitude smaller than the previous theoretical predictions, and our theoretical prediction in total is about an order of magnitude smaller than the recent CLEO measurement on the branching fraction B(Υ\to J/ψ+X). It indicates that the J/ψproduction mechanism in Υdecay is not well understood, and further theoretical work and experimental analysis are still necessary.