Color-Octet Charmonium Production in Top Quark Decays

Abstract

We calculate the direct production rate of $J/\psi$ in top quark decays. The color-octet $J/\psi$ production via $t\to W^{+}bJ/\psi$ is shown to have a large branching ratio of order $1.5\times 10^{-4}$, which is over an order of magnitude higher than that of the color-singlet $J/\psi$ production via $t\to W^{+}bJ/\psi gg$ or $t\to W^{+}b{\chi }_{cJ}g$ followed by ${\chi }_{cJ}\to J/\psi \gamma$. This result can be used as a powerful tool to test the importance of the color-octet mechanism in heavy quarkonium production.

Comments: 10 pages LaTex (2 figures in PS-file)