Measurement of Longitudinal Spin Transfer to Lambda Hyperons in Deep-Inelastic Lepton Scattering

Abstract

Spin transfer in deep-inelastic Lambda electroproduction has been studied with the HERMES detector using the 27.6 GeV polarized positron beam in the 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 (sys); 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.

8 pages, 3 figures; new version has an expanded discussion and small format changes

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Cited by in corpus (27)

• Parton Fragmentation Functions
• Longitudinal Spin Transfer to the $\Lambda$ Hyperon in Semi-Inclusive Deep-Inelastic Scattering
• Longitudinal Spin Transfer to $\Lambda$ and $\bar{\Lambda }$ Hyperons in Polarized Proton-Proton Collisions at $\sqrt{s}$ = 200 GeV
• A lattice study of the spin structure of the Lambda hyperon
• Quark Distributions of Octet Baryons from SU(3) Symmetry
• Anti-Lambda polarization in high energy pp collisions with polarized beam
• Hyperon polarization in ν_μcharged current interaction at the NOMAD energies
• Next-to-leading order QCD evolution of transversity fragmentation functions
• The Spin Alignment of Vector Mesons in High Energy pp Collisions
• Several Topics on Transverse Momentum-Dependent Fragmentation Functions
• Spin Transfers for Baryon Production in Polarized pp Collisions at RHIC-BNL
• Longitudinal polarization of hyperon and anti-hyperon in semi-inclusive deep-inelastic scattering
• Polarized Lambda hyperon production in Semi-inclusive deep inelastic scattering off an unpolarized nulceon target
• Anti-Hyperon polarization in high energy pp collisions with polarized beams
• Spin transfer and polarization of antihyperons in lepton induced reactions
• Dihadron helicity correlation in photon-nucleus collisions
• Suppression of Spin Transfer to $\Lambda$ Hyperon in Deep-Inelastic Scattering
• Spin Content of Lambda in QCD Sum Rules
• Ratio of $\bar{\Lambda }/\Lambda$ in Semi-inclusive Electroproduction
• Evidence for SU(3) symmetry breaking from hyperon production
• Hyperon polarization in e^-p --> e^-HK with polarized electron beams
• Particle-Antiparticle Asymmetries of $\Lambda$ Production in Hadron-Nucleon Collisions
• Mass Suppression in Octet Baryon Production
• Probing Polarized Gluon Distributions through Charmed Hadron Production in Polarized pp Collisions at BNL--RHIC Energy
• Spin structure of nucleon and spin transfer in high energy fragmentation process
• Status of Spin Physics - Experimental Summary
• Longitudinal spin transfer of Lambda and anti-Lambda in polarized pp collisions at \sqrt s=200 GeV at STAR