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134 - J. Huang , K. Allada , C. Dutta 2011
We report the first measurement of the double-spin asymmetry $A_{LT}$ for charged pion electroproduction in semi obreakdash-inclusive deep obreakdash-inelastic electron scattering on a transversely polarized $^{3}$He target. The kinematics focused on the valence quark region, $0.16<x<0.35$ with $1.4<Q^{2}<2.7,textrm{GeV}^{2}$. The corresponding neutron $A_{LT}$ asymmetries were extracted from the measured $^{3}$He asymmetries and proton over $^{3}$He cross section ratios using the effective polarization approximation. These new data probe the transverse momentum dependent parton distribution function $g_{1T}^{q}$ and therefore provide access to quark spin-orbit correlations. Our results indicate a positive azimuthal asymmetry for $pi^{-}$ production on $^{3}$He and the neutron, while our $pi^{+}$ asymmetries are consistent with zero.
75 - X. Qian , K. Allada , C. Dutta 2011
We report the first measurement of target single spin asymmetries in the semi-inclusive $^3{He}(e,epi^pm)X$ reaction on a transversely polarized target. The experiment, conducted at Jefferson Lab using a 5.9 GeV electron beam, covers a range of 0.14 $< x <$ 0.34 with 1.3 $<Q^2<$ 2.7 GeV$^2$. The Collins and Sivers moments were extracted from the azimuthal angular dependence of the measured asymmetries. The extracted $pi^pm$ Collins moments for $^3$He are consistent with zero, except for the $pi^+$ moment at $x=0.34$, 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 the measured cross section ratio of proton to $^3$He, and are largely consistent with the predictions of phenomenological fits and quark model calculations.
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