Single-spin azimuthal asymmetries in electroproduction of neutral pions in semi-inclusive deep-inelastic scattering
Additional Document Info
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 (Formula presented) moment of the cross section is (Formula presented) This result is compared to single-spin asymmetries for charged pion production measured in the same kinematic range. The (Formula presented) asymmetry is of the same size as the (Formula presented) 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. 2001 The American Physical Society.