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arXiv 1005.4524hep-phhep-exnucl-exnucl-th
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自旋为1的强子中的张量极化夸克和反夸克分布函数

Tensor-polarized quark and antiquark distribution functions in a spin-one hadron

S. Kumano

摘要:

理解轨道角动量贡献对于在部分子水平上阐明核子自旋问题是至关重要的。自旋为1的强子的扭二结构函数b_1和b_2可以探测轨道角动量效应,这反映了与目前自旋为1/2的核子研究不同的一个方面,因为如果内部组分处于S态,它们应该消失。这些结构函数与自旋为1的强子的张量结构有关。对这种张量结构的研究将为高能自旋物理开辟一个新的领域。结构函数b_1和b_2分别用张量极化夸克和反夸克分布delta_T-q和delta_T-qbar描述。本文利用氘b_1结构函数的HERMES数据,分析了以简单的x依赖函数形式提取分布delta_T-q和delta_T-qbar的方法。通过分析,提出了张量极化价分布函数和反夸克分布函数的最佳分布。如果我们施加一个约束,张量极化的价夸克分布的一阶矩为零,得到一个有限的张量极化的反夸克。研究产生有限张量极化反夸克分布的物理机制是一个有趣的问题。

英文摘要:

To understand orbital-angular-momentum contributions is becoming crucial for clarifying nucleon-spin issue in the parton level. Twist-two structure functions b_1 and b_2 for spin-one hadrons could probe orbital-angular-momentum effects, which reflect a different aspect from current studies for the spin-1/2 nucleon, since they should vanish if internal constituents are in the S state. These structure functions are related to tensor structure in spin-one hadrons. Studies of such tensor structure will open a new field of high-energy spin physics. The structure functions b_1 and b_2 are described by tensor-polarized quark and antiquark distributions delta_T-q and delta_T-qbar. Using HERMES data on the b_1 structure function for the deuteron, we made an analysis of extracting the distributions delta_T-q and delta_T-qbar in a simple x-dependent functional form. Optimum distributions are proposed for the tensor-polarized valence and antiquark distribution functions from the analysis. A finite tensor polarization is obtained for antiquarks if we impose a constraint that the first moments of tensor-polarized valence-quark distributions vanish. It is interesting to investigate a physics mechanism to create a finite tensor-polarized antiquark distribution.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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