Flavor decomposition of the polarized quark distributions in the nucleon from inclusive and semi-inclusive deep-inelastic scattering.

Journal Article · Thu Oct 07 00:00:00 EDT 1999 · Phys. Lett. B

DOI:https://doi.org/10.1016/S0370-2693(99)00964-8· OSTI ID:943120

Ackerstaff, K; Airapetian, A; Akopov, N; Akushevich, I; Amarian, M; De Schepper, D; Gao, H; Hansen, J -O; Jackson, H E; Jones, C; Makins, N C. R.; O'Neill, T G; Potterveld, D H; DESY,; Zeuthen, DESY

Spin asymmetries of semi-inclusive cross sections for the production of positively and negatively charged hadrons have been measured in deep-inelastic scattering of polarized positrons on polarized hydrogen and {sup 3}He targets, in the kinematic range 0.023<x<0.6 and 1 GeV{sup 2}<Q{sup 2}<10 GeV{sup 2}. Polarized quark distributions are extracted as a function of x for up (u + {ovr u}) and down (d + {ovr d} ) flavors. The up quark polarization is positive and the down quark polarization is negative in the measured range. The polarization of the sea is compatible with zero. The first moments of the polarized quark distributions are presented. The isospin non-singlet combination {Delta}q{sub 3} is consistent with the prediction based on the Bjorken sum rule. The moments of the polarized quark distributions are compared to predictions based on SU(3){sub f} flavor symmetry and to a prediction from lattice QCD.

• Research Organization: Argonne National Lab. (ANL), Argonne, IL (United States)
• Sponsoring Organization: USDOE Office of Science (SC); National Science Foundation (NSF); FOR
• DOE Contract Number: DE-AC02-06CH11357
• OSTI ID: 943120
• Report Number(s): ANL/PHY/JA-37662; PYLBAJ; TRN: US201002%%607
• Journal Information: Phys. Lett. B, Vol. B, Issue 464 ; Oct. 7, 1999; ISSN 0370-2693
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CROSS SECTIONS
DECOMPOSITION
DEEP INELASTIC SCATTERING
FLAVOR MODEL
HADRONS
HELIUM
HYDROGEN
ISOSPIN
NUCLEONS
POLARIZATION
POLARIZED TARGETS
POSITRONS
PRODUCTION
QUANTUM CHROMODYNAMICS
QUARKS
SPIN
SUM RULES
SYMMETRY