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 sin phi 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 pi (0) asymmetry is of the same size as the pi (+) 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.

Single-spin azimuthal asymmetries in electroproduction of neutral pions in semi-inclusive deep-inelastic scattering

CIULLO, Giuseppe;FERRETTI, Paola;LENISA, Paolo;MASOLI, Francesco Antonio;REGGIANI, DAVIDE;
2001

Abstract

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 sin phi 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 pi (0) asymmetry is of the same size as the pi (+) 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
A., Airapetian; N., Akopov; Z., Akopov; M., Amarian; E. C., Aschenauer; H., Avakian; R., Avakian; A., Avetissian; E., Avetissian; P., Bailey; B., Bain...espandi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11392/1683370
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