Exclusive decay of $\Upsilon$ into $J/\psi+\chi_{c0,1,2}$

TL;DR

This paper analyzes the exclusive decay of the Upsilon meson into double charmonium states, considering multiple decay mechanisms and their interference, predicting observable branching fractions at future colliders.

Contribution

It provides a comprehensive calculation of Upsilon decays into J/psi and chi_c states within the NRQCD framework, including strong, electromagnetic, and radiative channels with interference effects.

Findings

Branching fractions of order 10^{-6} for certain decay channels.

Predictions are testable at future Super B factories.

Includes interference effects among decay mechanisms.

Abstract

We study the $\Upsilon$ 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 $\Upsilon(1S,2S,3S)\to J/\psi+\chi_{c1,0}$ are predicted to have the branching fractions of order $10^{-6}$, which should be observed in the prospective Super $B$ factory.