Final-state rescattering in ${\bar{B}}_{(s)}^0\to \hat{I}{›}_c^{+}\bar{\hat{I}}{›}_c^{-}$ decays

Abstract

The LHCb Collaboration has recently reported the first observation of the decay ${\bar{B}}_s^0\to \hat{I}{›}_c^{+}\bar{\hat{I}}{›}_c^{-}$, along with measurements of the branching fractions for both ${\bar{B}}^0\to \hat{I}{›}_c^{+}\bar{\hat{I}}{›}_c^{-}$ and ${\bar{B}}_s^0\to \hat{I}{›}_c^{+}\bar{\hat{I}}{›}_c^{-}$. In this work, we investigate these two decays within the framework of final state re-scattering. Our results show that the predicted branching fractions are consistent with the experimental measurements, indicating the significant role of long-distance final-state interactions in such baryonic B decays. Furthermore, we present predictions for the direct CP asymmetries and the asymmetry parameters. Numerically, both decays exhibit nearly vanishing CP asymmetries, while ${\bar{B}}^0\to \hat{I}{›}_c^{+}\bar{\hat{I}}{›}_c^{-}$ displays a sizable longitudinal polarization, providing a sensitive observable for testing our theoretical framework in future experimental measurements.

14 pages. 2 figures