Rare dileptonic decays of Λ_b in a quark model

Abstract

Hadronic form factors for the rare weak transitions ${\Lambda }_b\to {\Lambda }^{(\ast )}$ are calculated using a nonrelativistic quark model. The form factors are extracted in two ways. An analytic extraction using single component wave functions (SCA) with the quark current being reduced to its nonrelativistic Pauli form is employed in the first method. In the second method, the form factors are extracted numerically using the full quark model wave function (MCN) with the full relativistic form of the quark current. Although there are differences between the two sets of form factors, both sets satisfy the relationships expected from the heavy quark effective theory (HQET). Differential decay rates, branching ratios and forward-backward asymmetries (FBAs) are calculated for the dileptonic decays ${\Lambda }_b\to {\Lambda }^{(\ast )}{\ell }^{+}{\ell }^{-}$, for transitions to both ground state and excited daughter baryons. Inclusion of the long distance contributions from charmonium resonances significantly enhances the decay rates. In the MCN model the $\Lambda (1600)$ mode is the dominant mode in the $\mu$ channel when charmonium resonances are considered; the $\Lambda (1520)$ mode is also found to have a comparable branching ratio to that of the ground state in the $\mu$ channel.

Version accepted to International Journal of Modern Physics A

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Cited by in corpus (38)

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• Rare baryon decays Lambda_b -> Lambda l+ l- (l=e, mu, tau) and Lambda_b -> Lambda gamma : Differential and total rates, lepton- and hadron-side forward-backward asymmetries
• Test of lepton universality with ${\Lambda }_b^0\to p{K}^{-}{\ell }^{+}{\ell }^{-}$ decays
• Nonleptonic two-body decays of single heavy baryons ${\Lambda }_Q$, ${\Xi }_Q$, and ${\Omega }_Q$ $(Q=b,c)$ induced by $W$ emission in the covariant confined quark model
• Polarization effects in the cascade decay Lambda_b -> Lambda(-> p pi-) + J/psi(-> l+ l-) in the covariant confined quark model
• Measurement of the differential branching fraction of the decay ${\Lambda }_b^0\to \Lambda {\mu }^{+}{\mu }^{-}$
• Lambda_b -> Lambda l+ l- form factors and differential branching fraction from lattice QCD
• Angular distribution of polarised ${\Lambda }_b$ baryons decaying to $\Lambda {\ell }^{+}{\ell }^{-}$
• ${\Lambda }_c\to {\Lambda }^{\ast }(1520)$ form factors from lattice QCD and improved analysis of the ${\Lambda }_b\to {\Lambda }^{\ast }(1520)$ and ${\Lambda }_b\to {\Lambda }_c^{\ast }(2595,2625)$ form factors
• ${\Lambda }_b\to {\Lambda }^{\ast }(1520){\ell }^{+}{\ell }^{-}$ form factors from lattice QCD
• Heavy baryons as polarimeters at colliders
• Rare ${\Lambda }_b\to \Lambda l^{+}{l}^{-}$ and ${\Lambda }_b\to \Lambda \gamma$ decays in the relativistic quark model
• Angular analysis of the rare decay ${\Lambda }_b\to \Lambda (1520)(\to NK){\ell }^{+}{\ell }^{-}$
• Lepton mass effects and angular observables in ${\Lambda }_b\to \Lambda (\to p\pi ){\ell }^{+}{\ell }^{-}$
• The ${\Lambda }_b\to {\Lambda }^{\ast }(1520)(\to N\bar{K}){\ell }^{+}{\ell }^{-}$ decay at low-recoil in HQET
• Angular Distributions for Multi-body Semileptonic Charmed Baryon Decays
• CP Violation of Baryon Decays with $N\pi$ Scatterings
• ${\Lambda }_c$ Semileptonic Decays in a Quark Model
• Towards an assessment of the ATLAS data on the branching ratio Gamma(Lambda_b(0) -> psi(2S) Lambda(0))/Gamma(Lambda_b(0) -> J/psi Lambda(0))
• Form Factor Counting and HQET Matching for New Physics in ${\Lambda }_b\to {\Lambda }_c^{\ast }l\nu$
• Lepton polarization asymmetries for FCNC decays of the ${\Lambda }_b$ baryon
• Charmonium decays of beauty baryons in the perturbative QCD approach
• Searching for tetraquark through weak decays of b-baryons
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• Transition form factors and angular distributions of the ${\mathbf{\Lambda }}_{\mathbf{b}}\to \mathbf{\Lambda }(1520)(\to \mathbf{N}\bar{\mathbf{K}}){\mathbf{\ell }}^{+}{\mathbf{\ell }}^{-}$ decay supported by baryon spectroscopy
• A detailed study of the ${\Lambda }_b\to \Lambda {\ell }^{+}{\ell }^{-}$ decays in the Standard Model
• Measurement of the ratio of branching fractions of the decays ${\Lambda }_b^0\to \psi (2S)\Lambda$ and ${\Lambda }_b^0\to J/\psi \Lambda$
• Bottomed baryon decays with invisible Majorana fermions
• Angular distribution of ${\Lambda }_b^0\to p{K}^{-}{\ell }^{+}{\ell }^{-}$ decays comprising $\Lambda$ resonances with spin up to $\le 5/2$
• ${\Lambda }_b\to \Lambda (\to p{\pi }^{-}){\ell }^{+}{\ell }^{-}$ as probe of CP-violating New Physics
• ${\Xi }_b\to \Xi$ form factors from lattice QCD and Standard-Model predictions for ${\Xi }_b\to \Xi {\mu }^{+}{\mu }^{-}$ and ${\Xi }_b\to \Xi \gamma$ decays
• Semileptonic neutral current decays of ${\Xi }_b$ with dileptons or dineutrinos in the final state
• Baryons and baryoniums in the perspective of QCD sum rules
• Amplitude analysis of the ${\Lambda }_b^0\to p{K}^{-}\gamma$ decay
• Probing new physics effects in ${\Lambda }_b\to \Lambda (\to p{\pi }^{-}){\ell }^{+}{\ell }^{-}$ decay via model independent approach
• Analysis of ${\Lambda }_b^0\to p{K}^{-}{\mu }^{+}{\mu }^{-}$ decays
• Forward-backward asymmetries in ${\Lambda }_b\to \Lambda l^{+}{l}^{-}$ in Bethe-Salpeter equation approach