Measurement of single-spin azimuthal asymmetries in semi-inclusive electroproduction of pions and kaons on a longitudinally polarised deuterium target

Single-spin asymmetries have been measured for semi-inclusive electroproduction of pi(+), pi(-), pi(0) and K+ mesons in deep-inelastic scattering off a longitudinally polarised deuterium target. The asymmetries appear in the distribution of the hadrons in the azimuthal angle phi around the virtual photon direction, relative to the lepton scattering plane. The corresponding analysing powers in the sinphi moment of the cross section are 0.012 +/- 0.002(stat.) +/- 0.002(syst.) for pi(+), 0.006 +/- 0.003(stat.) +/- 0.002(syst.) for pi(-), 0.021 +/- 0.005(stat.) +/- 0.003(syst.) for pi(0) and 0.013 +/- 0.006(stat.) +/- 0.003(syst.) for K The sin 20 moments are compatible with zero for all particles. (C) 2003 Elsevier Science B.V All rights reserved.