Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA.
Phys Rev Lett. 2010 Dec 31;105(26):262002. doi: 10.1103/PhysRevLett.105.262002. Epub 2010 Dec 22.
We report the first measurement of the transverse momentum dependence of double-spin asymmetries in semi-inclusive production of pions in deep-inelastic scattering off the longitudinally polarized proton. Data have been obtained using a polarized electron beam of 5.7 GeV with the CLAS detector at the Jefferson Lab (JLab). Modulations of single spin asymmetries over the azimuthal angle between lepton scattering and hadron production planes ϕ have been measured over a wide kinematic range in Bjorken x and virtual photon squared four-momentum Q2. A significant nonzero sin2ϕ single spin asymmetry was observed for the first time indicating strong spin-orbit correlations for transversely polarized quarks in the longitudinally polarized proton.
我们报告了在深度非弹性散射中，质子纵向极化的条件下，测量到的π介子的双自旋不对称性的横动量依赖性的首次测量结果。该数据是使用 5.7GeV 的极化电子束在杰斐逊实验室（JLab）的 CLAS 探测器上获得的。在 Bjorken x 和虚拟光子平方四维动量 Q2 的宽能区范围内，测量了在轻子散射和强子产生平面之间的方位角 ϕ 上的单自旋不对称性的调制。首次观察到了一个显著的非零的 sin2ϕ 单自旋不对称性，这表明在纵向极化质子中，横向极化夸克具有强烈的自旋-轨道相关性。
