Spin content of Λ and its longitudinal polarization in e⁺ e⁻ annihilation at high energies

Abstract

Longitudinal polarization of Λ produced in e+e- annihilation at CERN LEP energies is calculated in a picture for the spin content of Λ which is consistent with the polarized deep inelastic lepton-nucleon scattering data and SU(3) flavor symmetry for hyperon decay, so that the spin of Λ is not completely carried by its s-valence quark. A comparison with the recent ALEPH data and the results of earlier calculations based on the static quark model, in which the spin of Λ is completely determined by the s quark, is given. The result shows that further measurements of such polarization should provide useful information as to the question of which picture is more suitable in describing spin effects in the fragmentation processes.