DOI 10.1007/s100520000447
polarization and spin transfer
in lepton deep-inelastic scattering
B.-Q. Ma1,2,3 - I. Schmidt4 - J. Soffer5 - J.-J. Yang4,6
1 Department of Physics, Peking University,
Beijing 100871, P.R. China
2 CCAST (World Laboratory),
P.O. Box 8730, Beijing 100080, P.R. China
3 Institute of High Energy Physics, Academia
Sinica, P.O. Box 918(4), Beijing 100039, P.R. China
4 Departamento de Física, Universidad
Técnica Federico Santa María,
Casilla 110-V,
Valparaíso, Chile
5 Centre de Physique Th
orique,
CNRS, Luminy Case 907, 13288 Marseille Cedex 9, France
6 Department of Physics, Nanjing Normal
University,
Nanjing 210097, P.R. China
Received: 5 April 2000 / Published online: 26 July 2000 - © Springer-Verlag 2000
Abstract
The flavor and helicity distributions of the
and
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
and
,
and calculate the z-dependence
of the longitudinal spin transfer to
and
in lepton deep-inelastic scattering
(DIS). It is shown that the spin transfer to the
is
compatible with the first HERMES results at DESY, and further tests
are suggested. We also make predictions for the z-dependence
of the
and
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
(or the
sea antiquarks in
)
are negatively polarized,
whereas the sea antiquarks in the
(or the sea quarks in
)
are positively polarized. The asymmetry of the
polarized fragmentation functions of the sea quarks and antiquarks to
and
provides a way to understand the
different behavior between the
and
spin
transfers observed in the recent E665 experiment at FNAL.
Copyright Società Italiana di Fisica, Springer-Verlag 2000