Rates and $CP$ asymmetries of Charmless Two-body Baryonic $B_{u,d,s}$ Decays

Abstract

With the experimental evidences of $\overline{B}{}^0\to p\overline{p}$ and $B^{-}\to \Lambda \overline{p}$ decays, it is now possible to extract both tree and penguin amplitudes of the charmless two-body baryonic $B$ decays for the first time. The extracted penguin-tree ratio agrees with the expectation. Using the topological amplitude approach with the experimental results on $\overline{B}{}^0\to p\overline{p}$ and $B^{-}\to \Lambda \bar{p}$ decay rates as input, predictions on all other ${\overline{B}}_q\to \mathcal{B}\overline{\mathcal{B}}$, $\mathcal{B}\overline{\mathcal{D}}$, $\mathcal{D}\overline{\mathcal{B}}$ and $\mathcal{D}\overline{\mathcal{D}}$ decay rates, where $\mathcal{B}$ and $\mathcal{D}$ are the low lying octet and decuplet baryons, respectively, are given. It is non-trivial that the results do not violate any existing experimental upper limit. From the analysis it is understandable that why $\overline{B}{}^0\to p\overline{p}$ and $B^{-}\to \Lambda \bar{p}$ modes are the first two modes with experimental evidences. Relations on rates are verified using the numerical results. We note that the predicted $B^{-}\to p\overline{{\Delta }^{++}}$ rate is close to the experimental bound, which has not been updated in the last ten years. Direct $CP$ asymmetries of all ${\overline{B}}_q\to \mathcal{B}\overline{\mathcal{B}}$, $\mathcal{B}\overline{\mathcal{D}}$, $\mathcal{D}\overline{\mathcal{B}}$ and $\mathcal{D}\overline{\mathcal{D}}$ modes are explored. Relations on $CP$ asymmetries are examined using the numerical results. The direct $CP$ asymmetry of $\overline{B}{}^0\to p\overline{p}$ decay can be as large as $\pm 50\%$. The $CP$ asymmetries of $\Delta S=-1$ pure penguin modes are constrained to be of few $\%$. These modes are expected to be sensitive to New Physics contributions and are good candidates to be added to the list of the tests of the Standard Model.

To appear in Phys. Rev. D, 58 pages, 3 figures, 17 tables, some useful formulas from arXiv:1312.2335 are collected (with minor correction) in appendices

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Cited by in corpus (6)

• Weak Decays of Doubly Heavy Baryons: SU(3) Analysis
• First observation of the rare purely baryonic decay $B^0\to p\bar{p}$
• Search for the rare hadronic decay $B_s^0\to p\bar{p}$
• Two-body Baryonic $B_{u,d,s}$ and $B_c$ to Charmless Final State Decays
• Study of charmless two-body baryonic $B$ decays
• Observation of the rare baryonic decay $B^{+}\to p\bar{\Lambda }$ and measurement of its weak decay parameter