Color-Octet Charmonium Production in Top Quark Decays

Abstract

We calculate the direct production rate of $J/ψ$ in top quark decays. The color-octet $J/ψ$ production via $t\rightarrow W^+ b J/ψ$ 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 $J/ψ$ production via $t\rightarrow W^+ b J/ψ~g~g $ or $t\rightarrow W^+ b~χ_{cJ}~g$ followed by $χ_{cJ}\rightarrow J/ψ~γ$. This result can be used as a powerful tool to test the importance of the color-octet mechanism in heavy quarkonium production.