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\(\Lambda, \bar{\Lambda}\) polarization and spin transfer in lepton deep-inelastic scattering

  • B.-Q. Ma
  • I. Schmidt
  • J. Soffer
  • J.-J. Yang
Theoretical physics

Abstract.

The flavor and helicity distributions of the \(\Lambda\) and \(\bar{\Lambda}\) hyperons for both valence and sea quarks are calculated in a perturbative QCD (pQCD) based model. We relate these quark distributions to the fragmentation functions of \(\Lambda\) and \(\bar{\Lambda}\), and calculate the z-dependence of the longitudinal spin transfer to \(\Lambda\) and \(\bar{\Lambda}\) in lepton deep-inelastic scattering (DIS). It is shown that the spin transfer to the \(\Lambda\) is compatible with the first HERMES results at DESY, and further tests are suggested. We also make predictions for the z-dependence of the \(\Lambda\) and \(\bar{\Lambda}\) longitudinal polarizations in neutrino (antineutrino) DIS processes. We investigate the sea contribution to the fragmentation functions, and we test a possible scenario where the sea quarks in \(\Lambda\) (or the sea antiquarks in \(\bar{\Lambda}\)) are negatively polarized, whereas the sea antiquarks in the \(\Lambda\) (or the sea quarks in \(\bar{\Lambda}\)) are positively polarized. The asymmetry of the polarized fragmentation functions of the sea quarks and antiquarks to \(\Lambda\) and \(\bar{\Lambda}\) provides a way to understand the different behavior between the \(\Lambda\) and \(\bar{\Lambda}\) spin transfers observed in the recent E665 experiment at FNAL.

Keywords

Fragmentation Function Quark Distribution Longitudinal Polarization Spin Transfer Longitudinal Spin 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag Berlin Heidelberg 2000

Authors and Affiliations

  • B.-Q. Ma
    • 1
  • I. Schmidt
    • 2
  • J. Soffer
    • 3
  • J.-J. Yang
    • 2
  1. 1.Department of Physics, Peking University, Beijing 100871, P.R. ChinaCN
  2. 2.Departamento de Física, Universidad Técnica Federico Santa María, Casilla 110-V, Valparaíso, ChileCL
  3. 3.Centre de Physique Théorique, CNRS, Luminy Case 907, 13288 Marseille Cedex 9, FranceFR

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