Polarized \(\Lambda_b\to \Lambda_c l \bar{\nu}\) decay in perturbative QCD

We study the polarized \(\Lambda_b\) baryon semileptonic decay \(\Lambda_b \to \Lambda_cl{\bar\nu}\) using perturbative QCD factorization theorem. In this approach heavy baryon transition form factors are expressed as the convolutions of hard \(b\) quark decay amplitudes with universal \(\Lambda_b\)...

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Bibliographic Details
Published in:arXiv.org 2000-06
Main Authors: Hsien-Hung Shih, Shih-Chang, Lee, Hsiang-nan Li
Format: Article
Language:English
Subjects:
Baryons
Decay
Form factors
Leptons
Polarization
Wave functions
Online Access:Get full text
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Summary:We study the polarized \(\Lambda_b\) baryon semileptonic decay \(\Lambda_b \to \Lambda_cl{\bar\nu}\) using perturbative QCD factorization theorem. In this approach heavy baryon transition form factors are expressed as the convolutions of hard \(b\) quark decay amplitudes with universal \(\Lambda_b\) and \(\Lambda_c\) baryon wave functions. With the heavy baryon wave functions determined in our previous work, we predict the asymmetry parameter \(\alpha({\hat e})\equiv (N_+-N_-)/(N_++N_-)=-0.31 {\bf P}\cdot{\hat e}\), where \({\bf P}\) is the \(\Lambda_b\) baryon polarization, \({\hat e}\) a unit vector perpendicular to the \(\Lambda_b\) baryon momentum, \(N_+\) (\(N_-\)) the number of leptons whose momenta possess positive (negative) components along \({\hat e}\). This result is useful for extracting the transverse polarization of a \(\Lambda_b\) baryon from data of exclusive semileptonic decays.
ISSN:2331-8422