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arXiv 1209.0080nucl-thhep-ph
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由QCD求和规则计算核对称能

Nuclear Symmetry Energy from QCD sum rules

Kie Sang Jeong, Su Houng Lee

摘要:

本文用QCD求和规则计算了同位旋非对称核物质中的核子自能。取中子和质子的这两者之差,使我们能够用定域算符来表示核对称能的势部分。我们发现标量(矢量)自能部分对核对称能有负(正)贡献,这与相对论平均场论的结果一致。此外,我们发现,一个重要的贡献的标量自能的负贡献来自扭曲-4矩阵元,其领先的密度依赖性可以从深非弹性散射实验中提取。这表明扭曲4贡献部分地模拟了$δ$介子的交换,并且它构成了QCD核对称能起源的重要部分。我们的结果也将QCD求和规则方法在理解对称核物质的QCD变量的早期成功推广到非对称核物质的情况。

英文摘要:

We calculate the nucleon self-energies in isospin-asymmetric nuclear matter using QCD sum rules. Taking the difference of these for the neutron and proton enables us to express the potential part of the nuclear symmetry energy in terms of local operators. We find that the scalar (vector) self-energy part gives a negative (positive) contribution to the nuclear symmetry energy which is consistent with the results from relativistic mean-field theories. Moreover, we find that an important contribution to the negative contribution of the scalar self-energy comes from the twist-4 matrix elements, whose leading density dependence can be extracted from deep inelastic scattering experiments. This suggests that the twist-4 contribution partly mimics the exchange of the $δ$ meson and that it constitutes an essential part in the origin of the nuclear symmetry energy from QCD. Our result also extends an early success of QCD sum rule method in understanding the symmetric nuclear matter in terms of QCD variables to the asymmetric nuclear matter case.

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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