Quark helicity distributions in the nucleon for up, down, and strange quarks from semi-inclusive deep-inelastic scattering
Quark helicity distributions in the nucleon for up, down, and strange quarks from semi-inclusive deep-inelastic scattering
复制标题
DOI：
10.1103/physrevd.71.012003
复制
发表时间：
2004-07
影响因子：
5
通讯作者：
H. C. A. Airapetian;E. al.
中科院分区：
文献类型：
--
作者：
H. C. A. Airapetian;E. al.
利用纵向极化的氢和氚靶的极化深度非弹性散射数据，确定了双自旋截面的不对称性。通过对以前发表的数据的重新分析，得到了从氢产生正电子和负电子的包含性和半包含性不对称性。在一个极化的氢靶上测量了产生负的和正的介子和介子的包含性和半包含性的不对称性。在QCD分析中，根据这些不对称性计算了上夸克和下夸克以及反上夸克、反下夸克和奇异海夸克的螺旋度密度。上夸克的极化为正，下夸克的极化为负。在实验不确定度范围内，所有提取的海夸克偏振均为零，轻夸克海螺旋度密度具有风味对称性。所提取的夸克螺旋度密度在测量范围内的一阶矩和二阶矩与包含性数据的拟合是一致的。
Polarized deep-inelastic scattering data on longitudinally polarized hydrogen and deuterium targets have been used to determine double-spin asymmetries of cross sections. Inclusive and semi-inclusive asymmetries for the production of positive and negative pions from hydrogen were obtained in a reanalysis of previously published data. Inclusive and semi-inclusive asymmetries for the production of negative and positive pions and kaons were measured on a polarized deuterium target. The separate helicity densities for the up and down quarks and the anti-up, anti-down, and strange sea quarks were computed from these asymmetries in a ''leading order'' QCD analysis. The polarization of the up-quark is positive and that of the down-quark is negative. All extracted sea quark polarizations are consistent with zero, and the light quark sea helicity densities are flavor symmetric within the experimental uncertainties. First and second moments of the extracted quark helicity densities in the measured range are consistent with fits of inclusive data.