Single spin asymmetries in charged pion production from semi-inclusive deep inelastic scattering on a transversely polarized He3 target at Q2=1.4-2.7GeV2

Qian, X.; Allada, K.; Dutta, C.; Huang, J.; Katich, J.; Wang, Y.; Zhang, Y.; Aniol, K.; Annand, J. R. M.; Averett, T.; Benmokhtar, F.; Bertozzi, W.; Bradshaw, P. C.; Bosted, P.; Camsonne, A.; Canan, M.; Cates, G. D.; Chen, C.; Chen, J. P.; Chen, W.; Chirapatpimol, K.; Chudakov, E.; Cisbani, E.; Cornejo, J. C.; Cusanno, F.; Dalton, M. M.; Deconinck, W.; De Jager, C. W.; DE LEO, Raffaele; Deng, X.; Deur, A.; Ding, H.; Dolph, P. A. M.; Dutta, D.; El Fassi, L.; Frullani, S.; Gao, H.; Garibaldi, F.; Gaskell, D.; Gilad, S.; Gilman, R.; Glamazdin, O.; Golge, S.; Guo, L.; Hamilton, D.; Hansen, O.; Higinbotham, D. W.; Holmstrom, T.; Huang, M.; Ibrahim, H. F.; Iodice, M.; Jiang, X.; Jin, G.; Jones, M. K.; Kelleher, A.; Kim, W.; Kolarkar, A.; Korsch, W.; Lerose, J. J.; Li, X.; Li, Y.; Lindgren, R.; Liyanage, N.; Long, E.; H. J., Lu; Margaziotis, D. J.; Markowitz, P.; Marrone, S.; Mcnulty, D.; Meziani, Z. E.; Michaels, R.; Moffit, B.; Muñoz Camacho, C.; Nanda, S.; Narayan, A.; Nelyubin, V.; Norum, B.; Oh, Y.; Osipenko, M.; Parno, D.; Peng, J. C.; Phillips, S. K.; Posik, M.; Puckett, A. J. R.; Qiang, Y.; Rakhman, A.; Ransome, R. D.; Riordan, S.; Saha, A.; Sawatzky, B.; Schulte, E.; Shahinyan, A.; Shabestari, M. H.; Å. Irca, S.; Stepanyan, S.; Subedi, R.; Sulkosky, V.; Tang, L. G.; Tobias, A.; Urciuoli, G. M.; Vilardi, I.; Wang, K.; Wojtsekhowski, B.; Yan, X.; Yao, H.; Ye, Y.; Ye, Z.; Yuan, L.; Zhan, X.; Zhang, Y. W.; Zhao, B.; Zheng, X.; Zhu, L.; Zhu, X.; Zong, X.

doi:10.1103/PhysRevLett.107.072003

We report the first measurement of target single spin asymmetries in the semi-inclusive He-3(e; e' pi(+/-))X reaction on a transversely polarized target. The experiment, conducted at Jefferson Lab using a 5.9 GeV electron beam, covers a range of 0.16 < x < 0.35 with 1.4 < Q(2) < 2.7 GeV2. The Collins and Sivers moments were extracted from the azimuthal angular dependence of the measured asymmetries. The pi(+/-) Collins moments for He-3 are consistent with zero, except for the pi(+) moment at x = 0.35, which deviates from zero by 2.3 sigma. While the pi(-) Sivers moments are consistent with zero, the pi(+) Sivers moments favor negative values. The neutron results were extracted using the nucleon effective polarization and measured cross section ratios of proton to He-3, and are largely consistent with the predictions of phenomenological fits and quark model calculations.