Measurement of parton distributions of strange quarks in the nucleon from charged-kaon production in deep-inelastic scattering on the deuteron

摘要

The momentum and helicity density distributions of the strange quark sea in the nucleon are obtained in leading order from charged-kaon production in deep-inelastic scattering on the deuteron. The distributions are extracted from spin-averaged K+/- multiplicities, and from K+/- and inclusive double-spin asymmetries for scattering of polarized positrons by a polarized deuterium target. The shape of the momentum distribution is softer than that of the average of the a and a quarks. In the region of measurement 0.02 < x < 0.6 and Q(2) > 1.0 GeV2, the helicity distribution is zero within experimental uncertainties. (C) 2008 Elsevier B.V. All rights reserved.