J/psi production in top quark decays

We calculate the direct production rate of J/psi in top quark decays. The color-octet J/psi production via t-->W(+)bJ/psi is shown to have a large branching ratio of order 1.5x10(-4), which is over an order of magnitude higher than that of the color-singlet J/psi production via t-->W(+)bJ/psi gg or t-->W(+)b chi(cJ)g followed by chi(cJ)-->J/psi gamma. Our result can also be used as a tool to test the importance of the color-octet mechanism in heavy quarkonium production in the future.Astronomy & AstrophysicsPhysics, Particles & FieldsSCI(E)2ARTICLE52837-28395