Exclusive decay of ${\rm Y}$ into $J/\psi +{\chi }_{c0,1,2}$

Abstract

We study the ${\rm Y}$ exclusive decay into double charmonium, specifically, the $S$-wave charmonium $J/\psi$ plus the $P$-wave charmonium ${\chi }_{c0,1,2}$ in the NRQCD factorization framework. Three distinct decay mechanisms, i.e., the strong, electromagnetic and radiative decay channels are included and their interference effects are investigated. The decay processes ${\rm Y}(1S,2S,3S)\to J/\psi +{\chi }_{c1,0}$ are predicted to have the branching fractions of order $10^{-6}$, which should be observed in the prospective Super $B$ factory.

Comments: 22 pages, 9 figures, 3 tables