The effective radius for production of baryon-antibaryon pairs from $\psi$ decays

Abstract

By using the covariant L-S Scheme for the partial wave analysis, we deduce the ratios between the S-wave and D-wave contributions from the recent data of $\psi(1^-) \to B_8(1/2^+) \bar{B}_8(1/2^-)$ from the BESIII collaboration. For the $J/\psi\to \Lambda\bar{\Lambda}$ and $J/\psi(\psi(2S))\to \Sigma^{+}\bar{\Sigma}^{-}$, the ratios are fixed and the average angular momenta are computed to estimate the effective radii of these processes. The results show that the effective radii of these decays of $J/\psi(\psi(2S))$ are very small, which are around 0.04 fm. Thus, it is a nice place to search excited baryon resonances with lower spin in the decays of $J/\psi(\psi(2S))$. Furthermore, for the other $\psi(1^-) \to B_8(1/2^+) \bar{B}_8(1/2^-)$ reactions, we propose some methods to get such effective radius.