Evidence for a Single-Spin Azimuthal Asymmetry in Semi-inclusive Pion Electroproduction
Abstract
Single-spin asymmetries for semi-inclusive pion production in deep-inelastic scattering have been measured for the first time. A significant target-spin asymmetry of the distribution in the azimuthal angle φ of the pion relative to the lepton scattering plane was formed for π+ electroproduction on a longitudinally polarized hydrogen target. The corresponding analyzing power in the sinφ moment of the cross section is 0.022+/-0.005+/-0.003. This result can be interpreted as the effect of terms in the cross section involving chiral-odd spin distribution functions in combination with a chiral-odd fragmentation function that is sensitive to the transverse polarization of the fragmenting quark.
- Publication:
-
Physical Review Letters
- Pub Date:
- May 2000
- DOI:
- 10.1103/PhysRevLett.84.4047
- arXiv:
- arXiv:hep-ex/9910062
- Bibcode:
- 2000PhRvL..84.4047A
- Keywords:
-
- High Energy Physics - Experiment
- E-Print:
- 5 pages of RevTex, 3 ps figures, 2 tables