CP asymmetries in $B$ meson two-body baryonic decays

Abstract

We study the CP-odd and CP-even observables of the $B$ mesons decaying into a baryon and antibaryon. We estimate these observables through the ${}^3{P}_0$ model and chiral selection rule. The decay branching ratios of $B^{+}\to p\overline{\Lambda }$ and $B^0\to p\overline{p}$ are calculated to be $2.31\times 10^{-7}$ and $1.27\times 10^{-8}$, which are consistent with the current experiments, respectively. The effects of the $B-\overline{B}$ oscillations are considered, which largely suppress the direct CP asymmetries in the $B_s^0$ decays. We suggest the experiments to visit $B_s^0\to \Lambda (\to p{\pi }^{-})\overline{\Lambda }(\to \overline{p}{\pi }^{+})$, where the time-averaged CP-odd observables are estimated to be large. The direct CP asymmetries of $B^{+}\to p\overline{\Lambda }$ and $B^0\to p\overline{p}$ are found to be $26.2\%$ and $-3.1\%$ for a positive strong phase and $-36.9\%$ and $4.2\%$ for a negative strong phase, respectively.

Comments: 14 pages, 2 figures