Contribution of Colour-singlet Process $\Upsilon \to J/\Psi + c\bar{c}g$ to $\Upsilon \to J/\Psi + X$

Abstract

We show that the colour-singlet process $\Upsilon \to J/\Psi + c\bar{c}g$ significantly contributes to the inclusive process $\Upsilon \to J/\Psi + X$. We calculate the partial width and the momentum distribution of the produced $J/\Psi$ in this channel. The obtained width is comparable to the experimental data. The momentum distribution is fairly soft, which is in contrast to the results from the colour-octet processes discussed earlier in literature but is consistent with the CLEO measurements. Further experiments to check this contribution are suggested.