Intrinsic polarized strangeness and $\Lambda ^0$ polarization in deep-inelastic production

Abstract.

We propose a model for the longitudinal polarization of $\Lambda ^0$ baryons produced in deep-inelastic lepton scattering at any $x_{\mathrm {F}}$, based on static SU(6) quark-diquark wave functions and polarized intrinsic strangeness in the nucleon associated with individual valence quarks. The free parameters of the model are fixed by fitting NOMAD data on the longitudinal polarization of $\Lambda ^0$ hyperons in neutrino collisions. Our model correctly reproduces the observed dependences of the $\Lambda ^0$ polarization on the kinematic variables. Within the context of our model, the NOMAD data imply that the intrinsic strangeness associated with a valence quark has anticorrelated polarization. We also compare our model predictions with results from the HERMES and E665 experiments using charged leptons. Predictions of our model for the COMPASS experiment are also presented.