## Abstract

We present a measurement of semi-inclusive spin asymmetries for positively and negatively charged hadrons from deep inelastic scattering of polarised muons on polarised protons and deuterons in the range 0.003 < x < 0.7 and Q^{2} > 1 GeV^{2}. Compared to our previous publication on this subject, with the new data the statistical errors have been reduced by nearly a factor of two. From these asymmetries and our inclusive spin asymmetries we determine the polarised quark distributions of valence quarks and non-strange sea quarks at Q^{2} = 10 GeV^{2}. The polarised u valence quark distribution, Δu_{υ}(×), is positive and the polarisation increases with x. The polarised d valence quark distribution, Δd_{υ}(x), is negative and the non-strange sea distribution, Δq^{-}(x), is consistent with zero over the measured range of x. We find for the first moments (latin small letter esh)^{1}_{0}Δu_{υ}(x)d x = 0.77 ± 0.10 ± 0.08, (latin small letter esh)^{1}_{0}Δd_{υ}(x)d x = -0.52 ± 0.14 ± 0.09 and (latin small letter esh)^{1}_{0}Δq^{-}(x)d x = 0.01 ± 0.04 ± 0.03, where we assumed Δu^{-}(x) = Δd^{-}(x). We also determine for the first time the second moments of the valence distributions (latin small letter esh)^{1}_{0}xΔq_{υ}(x)d x.

Original language | English |
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Pages (from-to) | 180-190 |

Number of pages | 11 |

Journal | Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics |

Volume | 420 |

Issue number | 1-2 |

DOIs | |

State | Published - 19 Feb 1998 |