Analysis of the Lambda_b -> Lambda_c + l nu_l decay within a light-front constituent quark model

Abstract

We present an investigation of the Isgur-Wise form factor relevant for the semileptonic decay Lambda_b -> Λ_c + l nu_l performed within a light-front constituent quark model. Adopting different baryon wave functions it is found that the Isgur-Wise form factor depends sensitively on the baryon structure. It is shown however that the shape of the Isgur-Wise function in the full recoil range relevant for the Lambda_b -> Λ_c + l nu_l decay can be effectively constrained using recent lattice QCD results at low recoil. Then, the Lambda_b -> Λ_c + l nu_l decay is investigated including both radiative effects and first-order power corrections in the inverse heavy-quark mass. Our final predictions for the exclusive semileptonic branching ratio, the longitudinal and transverse asymmetries, and the longitudinal to transverse decay ratio are: Br(Lambda_b -> Λ_c + l nu_l) = (6.3 +/- 1.6) % |V_bc / 0.040|**2 ~ tau(Lambda_b) / (1.24 ps), a_L = -0.945 +/- 0.014, a_T = -0.62 +/- 0.09 and R_L/T = 1.57 +/- 0.15, respectively. Moreover, both the longitudinal asymmetry and the (partially integrated) longitudinal to transverse decay ratio are found to be only marginally affected by the model dependence of the Isgur-Wise form factor as well as by first-order power corrections; therefore, their experimental determination might be a very interesting tool for testing the SM and for investigating possible New Physics.

revised version with inclusion of PQCD corrections and improved discussion of power corrections, to appear in Physical Review D

References in corpus (4)

• Aspects Of Heavy Quark Theory
• First Lattice Study of Semileptonic Decays of Lambda_b and Xi_b Baryons
• Infinite Momentum Frame Calculation of Semileptonic Heavy Λ_b\toΛ_c Transitions Including HQET Improvements
• Isgur-Wise form factors of heavy baryons within a light-front constituent quark model

Cited by in corpus (14)

• Semileptonic decays of heavy baryons in the relativistic quark model
• Diquarks and Λ_{b}\toΛ_c weak decays
• Evaluating decay Rates and Asymmetries of ${\Lambda }_b$ into Light Baryons in LFQM
• Combined nonrelativistic constituent quark model and heavy quark effective theory study of semileptonic decays of Λ_b and Ξ_b baryons
• Revisiting semileptonic decays of ${\Lambda }_{b(c)}$ supported by baryon spectroscopy
• First Measurement of the Ratio of Branching Fractions B(Lambda_b to Lambda_c mu nu)/B(Lambda_b to Lambda_c pi)
• Phenomenology of ${\Xi }_b\to {\Xi }_c\tau \nu$ decays
• Light-cone Sum Rule Analysis of Semileptonic Decays ${\Lambda }_b^0\to {\Lambda }_c^{+}{\ell }^{-}{\overline{\nu }}_{\ell }$
• Semileptonic Transition of ${\Lambda }_b$ Baryon
• Heavy baryon wave functions, Bakamjian-Thomas approach to form factors, and observables in ${\Lambda }_b\to {\Lambda }_c\left({\frac{1}{2}}^{\pm }\right)\ell \overline{\nu }$ transitions
• Measuring c-quark polarization in W+c samples at ATLAS and CMS
• Semileptonic baryon decays ${\Xi }_b\to {\Xi }_c{\ell }^{-}{\bar{\nu }}_{\ell }$ in perturbative QCD
• Electromagnetic and weak decay of singly Heavy Baryons (Qqq)
• Semileptonic decay form factors of ${\Xi }_b^0\to {\Xi }_c^{+}\ell {\bar{\nu }}_{\ell }$ in HQET