Measurement of longitudinal spin transfer to {lambda} hyperons in deep-inelastic lepton scattering.

Journal Article · Sat Dec 01 04:00:00 EST 2001 · Phys. Rev. D

DOI:https://doi.org/10.1103/PhysRevD.64.112005· OSTI ID:943125

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

Spin transfer in deep-inelastic {Lambda} electroproduction has been studied with the HERMES detector using the 27.6 GeV polarized positron beam in the DESY HERA storage ring. For an average fractional energy transfer <z>=0.45, the longitudinal spin transfer from the virtual photon to the {Lambda} has been extracted. The spin transfer along the {Lambda} momentum direction is found to be 0.11{+-}0.17(stat){+-}0.03(syst); similar values are found for other possible choices for the longitudinal spin direction of the {Lambda}. This result is the most precise value obtained to date from deep-inelastic scattering with charged lepton beams, and is sensitive to polarized up quark fragmentation to hyperon states. The experimental result is found to be in general agreement with various models of the {Lambda} spin content, and is consistent with the assumption of helicity conservation in the fragmentation process.

• Research Organization: Argonne National Laboratory (ANL)
• Sponsoring Organization: SC; FOR; NSF
• DOE Contract Number: AC02-06CH11357
• OSTI ID: 943125
• Report Number(s): ANL/PHY/JA-37671
• Journal Information: Phys. Rev. D, Journal Name: Phys. Rev. D Journal Issue: 11 ; Dec. 1, 2001 Vol. 64; ISSN 1550-7998
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

43 PARTICLE ACCELERATORS
DEEP INELASTIC SCATTERING
DESY
ELECTROPRODUCTION
ENERGY TRANSFER
FRAGMENTATION
HELICITY
HERA STORAGE RING
HYPERONS
LEPTON BEAMS
LEPTONS
PHOTONS
POSITRON BEAMS
QUARKS
SPIN