Lepton polarization asymmetries for FCNC decays of the ${\Lambda }_b$ baryon

Abstract

Branching ratios, lepton forward-backward asymmetries, and lepton polarization asymmetries for the flavor-changing neutral current (FCNC) dileptonic decays of the ${\Lambda }_b$ baryon to the ground state and a number of excited state $\Lambda$ baryons are calculated using form factors extracted using wave functions from a constituent quark model. The SM branching ratios for the transition to the ground state calculated using these quark model form factors are consistent with the recent measurement reported by the LHCb collaboration. It is shown that the lepton polarization asymmetries are largely insensitive to the transition form factors and, therefore, to the effects of QCD in the nonperturbative regime. These observables can therefore provide somewhat model independent ways of extracting various combinations of the Wilson coefficients.

44 pages, 34 figures, To be submitted to IJMPA. arXiv admin note: substantial text overlap with arXiv:1108.6129

References in corpus (10)

• Heavy Baryons in a 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
• PQCD Calculation for ${\Lambda }_b\to \Lambda \gamma$ in the Standard Model
• Exclusive semileptonic decays of ${\Lambda }_b\to \Lambda l^{+}{l}^{-}$ in supersymmetric theories
• Semileptonic Decays of Heavy Omega Baryons in a Quark Model
• Testing New Physics Effects in $B\to K^{\ast }{\ell }^{+}{\ell }^{-}$
• Double Lepton Polarization in ${\Lambda }_b-->\Lambda l^{+}{l}^{-}$ Decay in the Standard Model with Fourth Generations Scenario
• The nature of Lambda(1405) hyperon resonance in chiral dynamics
• Rare B decays in a single Universal Extra Dimension scenario

Cited by in corpus (9)

• ${\Lambda }_b\to \Lambda {\ell }^{+}{\ell }^{-}$ form factors, differential branching fraction, and angular observables from lattice QCD with relativistic $b$ quarks
• Rare ${\Lambda }_b\to \Lambda l^{+}{l}^{-}$ and ${\Lambda }_b\to \Lambda \gamma$ decays in the relativistic quark model
• Comparative analysis of the ${\Lambda }_b\to \Lambda {\ell }^{+}{\ell }^{-}$ decay in the SM, SUSY and RS model with custodial protection
• 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
• Angular distribution of ${\Lambda }_b^0\to p{K}^{-}{\ell }^{+}{\ell }^{-}$ decays comprising $\Lambda$ resonances with spin up to $\le 5/2$
• Forward-backward asymmetries in ${\Lambda }_b\to \Lambda l^{+}{l}^{-}$ in Bethe-Salpeter equation approach
• ${\Xi }_b\to \Xi$ form factors from lattice QCD and Standard-Model predictions for ${\Xi }_b\to \Xi {\mu }^{+}{\mu }^{-}$ and ${\Xi }_b\to \Xi \gamma$ decays
• Amplitude analysis of the ${\Lambda }_b^0\to p{K}^{-}\gamma$ decay
• Semileptonic neutral current decays of ${\Xi }_b$ with dileptons or dineutrinos in the final state