Polarized Parton Distributions from Charged–Current Deep-Inelastic Scattering and Future Neutrino Factories

We discuss the determination of polarized parton distributions from charged– current deep–inelastic scattering experiments. We summarize the next-to-leading order treatment of charged–current polarized structure functions, their relation to polarized parton distributions and scale dependence, and discuss their description by means of a next-to-leading order evolution code. We discuss current theoretical expectations and positivity constraints on the unmeasured C–odd combinations ∆q − ∆q̄ of polarized quark distributions, and their determination in charged– current deep–inelastic scattering experiments. We give estimates of the expected errors on charged–current structure functions at a future neutrino factory, and perform a study of the accuracy in the determination of polarized parton distributions that would be possible at such a facility. We show that these measurements have the potential to distinguish between different theoretical scenarios for the proton spin structure. CERN-TH/2000-377 January 2001 † On leave from INFN, Sezione di Torino, Italy ∗ On leave from INFN, Sezione di Genova, Italy