Final-state rescattering in $\bar{B}^{0}_{(s)}\to \Lambda^{+}_{c}\bar{\Lambda}^{-}_{c}$ decays

TL;DR

This paper analyzes baryonic B meson decays involving Lambda_c particles, emphasizing the importance of final-state rescattering effects in explaining observed branching fractions and predicting CP asymmetries and polarization.

Contribution

It demonstrates that long-distance final-state interactions are crucial for understanding these decays and provides theoretical predictions consistent with recent experimental data.

Findings

Predicted branching fractions match experimental measurements.

Both decays have nearly zero direct CP asymmetries.

The decay ar B^0 ta; ar ta; ^+ta; ar ta; ^- shows sizable longitudinal polarization.

Abstract

The LHCb Collaboration has recently reported the first observation of the decay $\bar B_s^0\to \Lambda_c^+\bar\Lambda_c^-$, along with measurements of the branching fractions for both $\bar B^0\to \Lambda_c^+\bar\Lambda_c^-$ and $\bar B_s^0\to \Lambda_c^+\bar\Lambda_c^-$. 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 $\bar B^0\to \Lambda_c^+\bar\Lambda_c^-$ displays a sizable longitudinal polarization, providing a sensitive observable for testing our theoretical framework in future experimental measurements.