Lambda_b-Polarization from its Inclusive Semileptonic Decay

Abstract

We discuss the Lambda_b-polarization of the bottom baryon Lambda_b in its production and in its decay. Standard Model predictions for b-quark polarization on the Z-peak are reviewed, including beam-quark orientation effects and O(as) radiative corrections to the polarization. The b-quark polarization is expected to be handed over to the Lambda_b into which it fragments with a high degree of efficiency. We present several spin-momentum correlation measures of the spin of the Λ_b with the momenta of its decay products in its inclusive semileptonic decay. We estimate the strengths of the spin-momentum correlations in the Free Quark Decay (FQD) model and find that some of the measures provide good or very good analyzing power for measuring the polarization of the Lambda_b.

Lecture given at the conference "Production and Decay of Hyperons, Charm and Beauty Hadrons", Strassbourg, France, September 5-8, 1995; to appear in the Proceedings of this conference; 9 pages, LaTeX, 3 figures are included in uuencoded PostScript format; a new reference is added

References in corpus (6)

• QCD Predictions for Lepton Spectra in Inclusive Heavy Flavour Decays
• Distributions of leptons in decays of polarised heavy quarks
• Optimized Variables of the Study of ${\Lambda }_b$ Polarization
• QCD corrections to decays of polarised charm and bottom quarks
• Inclusive Semileptonic Decays of Polarized ${\Lambda }_b$ Baryons into Polarized $\tau$-Leptons
• Polar Angle Dependence of the Alignment Polarization of Quarks Produced in e^+e^- Annihilation

Cited by in corpus (4)

• Measurement of the Average Polarization of b Baryons in Hadronic Z^0 Decays
• Spin-Momentum Correlations in Inclusive Semileptonic Decays of Polarized ${\Lambda }_b$ Baryons
• Polarization and Distribution Function of ${\Lambda }_b$ Baryon
• $O({\alpha }_s)$ perturbative and nonperturbative corrections to polarized semileptonic ${\Lambda }_b$ decay distributions