Determination of polarized parton distribution functions with recent data on polarization asymmetries
Determination of polarized parton distribution functions with recent data on polarization asymmetries
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DOI：
10.1103/physrevd.74.014015
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发表时间：
2006-03
影响因子：
5
通讯作者：
M. Hirai;S. Kumano;N. Saito
中科院分区：
文献类型：
--
作者：
M. Hirai;S. Kumano;N. Saito
在量子色动力学(QCD)中，用新的自旋不对称实验数据进行了全局分析，以确定极化的部分子分布。新的数据集包括J-Lab、Hermes和COMPASS对轻子散射中的中子和氘的自旋不对称性的测量。我们的新分析还利用了极化$pp$碰撞中${\ensureath{\pi}}^{0}$产生的双自旋不对称性，通过PHENIX合作测量了${A}_{ll}^{{\susureath{\pi}}^{0}}$。由于这些新的数据，偏振的PDF的不确定性被降低。特别是，J-Lab、Hermes和指南针测量对于确定$\EnsureMath{\Delta}{d}_{v}(X)$在$x\EnsureMath{\sim}0.1$处确定$\EnsureMath{\Delta}\$\EnsureMath{\Delta}\Overline{q}(X)$非常有价值。PHENIX${\EnsureMath{\pi}}^{0}$数据显著降低了$\EnsureMath{\Delta}g(X)$的不确定性。此外，我们通过使用${g}_{1}^{d}$上的Hermes数据与在$x\ensureath{\sim}0.05$上的指南针数据比较，讨论了在$x$上对$\ensureath{\Delta}g(X)$的可能的约束。
Global analysis has been performed within the next-to-leading order in quantum chromodynamics (QCD) to determine polarized parton distributions with new experimental data in spin asymmetries. The new data set includes J-Lab, HERMES, and COMPASS measurements on spin asymmetry ${A}_{1}$ for the neutron and deuteron in lepton scattering. Our new analysis also utilizes the double-spin asymmetry for ${\ensuremath{\pi}}^{0}$ production in polarized $pp$ collisions, ${A}_{LL}^{{\ensuremath{\pi}}^{0}}$, measured by the PHENIX Collaboration. Because of these new data, uncertainties of the polarized PDFs are reduced. In particular, the J-Lab, HERMES, and COMPASS measurements are valuable for determining $\ensuremath{\Delta}{d}_{v}(x)$ at large $x$ and $\ensuremath{\Delta}\overline{q}(x)$ at $x\ensuremath{\sim}0.1$. The PHENIX ${\ensuremath{\pi}}^{0}$ data significantly reduce the uncertainty of $\ensuremath{\Delta}g(x)$. Furthermore, we discuss a possible constraint on $\ensuremath{\Delta}g(x)$ at large $x$ by using the HERMES data on ${g}_{1}^{d}$ in comparison with the COMPASS ones at $x\ensuremath{\sim}0.05$.