Rare decays of ${\Lambda }_b\to \Lambda \gamma$ and ${\Lambda }_b\to \Lambda l^{+}{l}^{-}$ in universal extra dimension model

Abstract

The exclusive weak decay of ${\Lambda }_b\to \Lambda \gamma$ and ${\Lambda }_b\to \Lambda l^{+}{l}^{-}$ are investigated in the Applequist-Cheng-Dobrescu model, which is an extension of the standard model in presence of universal extra dimensions. Employing the transition form factors obtained in the light-cone sum rues, we analyze how the invariant mass distribution, forward-backward asymmetry and polarization asymmetry of $\Lambda$ baryon of these decay modes can be used to constrain the only one additional free parameter with respect to the standard model, namely, the radius $R$ of the extra dimension. Our results indicate that the Kaluza-Klein modes can lead to approximately 25% suppression of the branching ratio of ${\Lambda }_b\to \Lambda \gamma$, however, their contributions can bring about 10% enhancement to the decay rate of ${\Lambda }_b\to \Lambda l^{+}{l}^{-}$. It is shown that the zero-position of forward-backward asymmetry of ${\Lambda }_b\to \Lambda {\mu }^{+}{\mu }^{-}$ is sensitive to the compactification parameter $R$ in this scenario, while the measurement of polarizations of $\Lambda$ baryon in the ${\Lambda }_b$ decays is not suitable to provide some valuable information for the universal extra dimension model.

22 pages, 6 figures, two references added

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Cited by in corpus (9)

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• Rare $B_s$ decays to $\eta$ and ${\eta }^{\prime }$ final states
• Investigation of the ${\Lambda }_b\to \Lambda {\ell }^{+}{\ell }^{-}$ transition in universal extra dimension using form factors from full QCD
• Studying ${\mathcal{B}}_1({\frac{1}{2}}^{+})\to {\mathcal{B}}_2({\frac{1}{2}}^{+}){\ell }^{+}{\ell }^{-}$ Semi-leptonic Weak Baryon Decays with the SU(3) Flavor Symmetry
• Double-Lepton Polarization Asymmetries and Branching Ratio in $B \rar K_{0}^{*}(1430) l^+ l^- $ transition from Universal Extra Dimension Model
• Imprints of CP violation asymmetries in rare ${\Lambda }_b\to \Lambda {\ell }^{+}{\ell }^{-}$ decay in family non-universal $Z^{\prime }$ model
• FCNC transitions of ${\Lambda }_b$ to neutron in Bethe-Salpeter equation approach
• Rare ${\Lambda }_b\to \Lambda l^{+}{l}^{-}$ decay in the Bethe-Salpeter equation approach
• Analysis of the semileptonic decays ${\Sigma }_b\to {\Sigma }_{c}l{\bar{\nu }}_l$, ${\Xi }_b^{\prime }\to {\Xi }_c^{\prime }l{\bar{\nu }}_l$ and ${\Omega }_b\to {\Omega }_{c}l{\bar{\nu }}_l$ in QCD sum rules