Clean Prediction of \CP violating processes $\psi$, $\varphi$ and ${\rm Y}(1S)$ decay to KsKs and KLKL

Abstract

The ratio of $K_S{K}_S$ ($K_L{K}_L$) and $K_S{K}_L$ production rates is calculated by considering $K^0-K^{0}bar$ oscillation in $J/\psi \to K^0{K}^{0}bar$ decay. The theoretical uncertainty due to strong interaction in $J/\psi$ decay is completely canceled in the ratio, therefore, the absolute branching fractions of the \CP violating processes of $J/\psi \to K_S{K}_S$ and $K_L{K}_L$ can be cleanly and model-independently determined in case that $J/\psi \to K_S{K}_L$ decay is precisely measured. In the future $\tau$-Charm factory, the expected \CP violating process of $J/\psi \to K_S{K}_S$ should be reached. It is important to measure $J/\psi$ to $K_S{K}_S$ and K_S K_L decays simultaneously, so that many systematic errors will be canceled. More precise measurements are suggested to examine the predicted isospin relation in $J/\psi \to KKbar$ decays. All results can be extended to decays of other vector quarkonia, $\varphi$, $\psi (2S)$ and ${\rm Y}(1S)$ and so on.

Comments: Version 2 is the same as published one at PRL