Penguin-induced Radiative Baryonic B Decays Revisited

Abstract

Weak radiative baryonic B decays $\bar{B}\to B_1{\bar{B}}_2\gamma$ mediated by the electromagnetic penguin process $b\to s\gamma$ are re-examined within the framework of the pole model. The meson pole contribution that has been neglected before is taken into account in this work. It is found that the intermediate $K^{\ast }$ contribution dominates in the $\Sigma \bar{p}\gamma$ mode and is comparable to the baryon pole effect in $\Lambda \bar{p}\gamma$ and $\Xi \bar{\Lambda }\gamma$ modes. The branching ratios for $B^{-}\to \Lambda \bar{p}\gamma$ and $B^{-}\to {\Xi }^0{\bar{\Sigma }}^{-}\gamma$ are of order $2.6\times 10^{-6}$ and $6\times 10^{-7}$, respectively. The threshold enhancement effect in the dibaryon mass spectrum is responsible by the meson pole diagram. We also study the angular distribution of the baryon in the dibaryon rest frame. The baryon pole diagrams imply that the antibaryon tends to emerge in the direction of the photon in the baryon-pair rest frame. The predicted angular asymmetry agrees with experiment for $B^{-}\to \Lambda \bar{p}\gamma$. Measurements of the correlation of the photon with the baryon allow us to discriminate between different models for describing the radiative baryonic B decays. For decays $B\to \Xi \bar{\Sigma }\gamma$, a large correlation of the photon to the $\bar{\Sigma }$ and a broad bump in the dibaryon mass spectrum are predicted.

10 pages, 4 figures

References in corpus (15)

• CP Violation and the CKM Matrix: Assessing the Impact of the Asymmetric B Factories
• Systematic approach to exclusive B ->V l^+l^-, V gamma decays
• The Radiative Decays B -> V gamma at Next-to-Leading Order in QCD
• Nonleptonic Weak Decays of Bottom Baryons
• Branching Ratios for $B\to K^{\ast }\gamma$ and $B\to \rho \gamma$ Decays in Next-to-Leading Order in the Large Eneregy Effective Theory
• 1/M Corrections to Baryonic Form Factors in the Quark Model
• Charmless Three-Body Baryonic B Decays
• Covariant Light-Front Approach for B to K* gamma, K_1 gamma, K*_2 gamma Decays
• Understanding $B\to D^{\ast -}N\bar{N}$ and Its Implications
• Prediction of Three-body $B^0\to {\rho }^{-}p\bar{n},{\pi }^{-}p\bar{n}$ Decay Rates
• Penguin-Induced Radiative Baryonic B Decays
• Radiative Baryonic $B$ Decays
• Hadronic B Decays to Charmed Baryons
• Search for $B^0\to p\bar{p}$, $\Lambda \bar{\Lambda }$ and $B^{+}\to p\bar{\Lambda }$ at Belle
• Radiative B decays to the axial $K$ mesons at next-to-leading order

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• Angular distributions in three-body baryonic B decays
• Exclusive Baryonic B Decays Circa 2005
• Study of $B\to p\bar{p}{K}^{\ast }$ and $B\to p\bar{p}\rho$
• Determination of Nucleon Form factors from Baryonic B Decays
• Charmful baryonic B\to {\bf B\bar B'}M_c decays
• Status of baryonic B decays