Asymmetry of Lambda Baryons in Hadronic Z^0 Decays

TL;DR

This paper reports measurements of polarization and asymmetry of Lambda baryons in Z^0 decays, providing insights into hadronization processes at high energies.

Contribution

It presents the first detailed measurements of Lambda baryon polarization and asymmetry in Z^0 decays, highlighting the asymmetry's consistency with theoretical models.

Findings

Significant longitudinal polarization observed at high momentum

No transverse polarization detected

Forward-backward asymmetry consistent with JETSET model

Abstract

The longitudinal polarization, the transverse polarization, and the forward-backward asymmetry of Lambda baryons have been measured using a sample of 4.34 million hadronic Z^0 decays collected with the OPAL detector at LEP between 1990 and 1995. These results are important as an aid to the understanding of hadronization mechanisms. Significant longitudinal polarization has been observed at intermediate and high momentum. For x_E = 2 E_{Lambda}/\sqrt{s}) > 0.3, the longitudinal polarization has been measured to be -32.9 +/- 5.5(stat) +/- 5.2(syst)%. We have observed no transverse polarization. A significant forward-backward asymmetry has been measured and can be described by a JETSET model.