S-wave nonleptonic hyperon decays and ${\Xi }_b^{-}\to {\pi }^{-}{\Lambda }_b$

Abstract

The decay ${\Xi }_b^{-}\to {\pi }^{-}{\Lambda }_b$ has recently been observed by the LHCb Collaboration at CERN. In contrast to most weak decays of $b$-flavored baryons, this process involves the decay of the strange quark in ${\Xi }_b$, and thus has features in common with nonleptonic weak decays of hyperons. Thanks to the expected pure S-wave nature of the decay in question in the heavy $b$ quark limit, we find that its amplitude may be related to those for S-wave nonleptonic decays of $\Lambda$, $\Sigma$, and $\Xi$ in a picture inspired by duality. The calculated branching fraction $\mathcal{B}({\Xi }_b^{-}\to {\pi }^{-}{\Lambda }_b)=(6.3\pm 4.2)\times 10^{-3}$ is consistent with the range allowed in the LHCb analysis. The error is dominated by an assumed 30\% uncertainty in the amplitude due to possible U(3) violation. A more optimistic view based on sum rules involving nonleptonic hyperon decay S-wave amplitudes reduces the error on the branching fraction to $2.0\times 10^{-3}$.

8 pages, 1 figure. Slightly revised version submitted to Phys. Rev. D

References in corpus (4)

• Evidence for the strangeness-changing weak decay ${\Xi }_b^{-}\to {\Lambda }_b^0{\pi }^{-}$
• Light-Quark Decays in Heavy Hadrons
• The decays ${\Xi }_b\to {\Lambda }_b\pi$ and diquark correlations in hyperons
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• Charmonium decays of beauty baryons in the perturbative QCD approach
• From ${\Xi }_b\to {\Lambda }_b\pi$ to ${\Xi }_c\to {\Lambda }_c\pi$
• Update on splitting of lifetimes of $c$ and $b$ hyperons within the heavy quark expansion and decays ${\Xi }_Q\to {\Lambda }_Q\pi$
• Studying Two-body Nonleptonic Weak Decays of Hyperons with Topological Diagram Approach
• Observation and branching fraction measurement of the decay ${\Xi }_b^{-}\to {\Lambda }_b^0{\pi }^{-}$