Type: Article
Publication Date: 2001-10-05
Citations: 162
DOI: https://doi.org/10.1103/physrevd.64.097101
A single-spin asymmetry in the azimuthal distribution of neutral pions relative to the lepton scattering plane has been measured for the first time in deep-inelastic scattering of positrons off longitudinally polarized protons. The analyzing power in the sinφ moment of the cross section is 0.019±0.007(stat)±0.003(syst). This result is compared to single-spin asymmetries for charged pion production measured in the same kinematic range. The π0 asymmetry is of the same size as the π+ asymmetry and shows a similar dependence on the relevant kinematic variables. The asymmetry is described by a phenomenological calculation based on a fragmentation function that represents sensitivity to the transverse polarization of the struck quark.Received 4 April 2001DOI:https://doi.org/10.1103/PhysRevD.64.097101©2001 American Physical Society