Production of polarized baryons in polarized and unpolarizede ⁺ e ⁻ collisions

Abstract

Polarized and unpolarizede ⁺ e ⁻ annihilation is considered in lowest order at energies 30–150 GeV taking γ andZ ⁰ exchange in the standardSU(2)×U(1) model into account. The fragmentation of polarized quarks into polarized baryons is described by two kinds of fragmentation functions; the first is based onSU(6) weights and empirical expressions for favoured and disfavoured fragmentation; the second is based upon a Monte Carlo model of the chain decay including helicities of quarks and hadrons. From the cross sections for$e^ + e^ - \to q\bar q$ and the fragmentation functions we obtain predictions for the baryon polarization as function of the collision energy and of kinematical variables.