Virtual meson cloud of the nucleon and deep inelastic lepton scattering.
Virtual meson cloud of the nucleon and deep inelastic lepton scattering.
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DOI：
10.1103/physrevd.53.2586
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发表时间：
1995-07
期刊：
影响因子：
--
通讯作者：
W. Koepf;L. Frankfurt;M. Strikman
中科院分区：
文献类型：
--
作者：
W. Koepf;L. Frankfurt;M. Strikman
我们讨论了S非微扰反夸克海是否完全归因于其虚介子云的问题，以及在本质上是否存在强子自由度和夸克-胶子自由度之间的平稳过渡的问题。我们考虑了{pi}和{italK}介子的贡献，并将它们与作为QCD演化方程的非微扰输入的核子{Close_QUOTE}S反夸克分布进行了比较。虽然我们的计算与基于数据的参数化是令人满意的，并且对于S反夸克海的味道破缺份额，我们的计算是令人满意的，并且与尺度无关，但味道单重态成分的描述相当差。我们发现，在介子云模型中，大的介子环动量{PARALLEL}{ITAL K}{PARALLEL}{近似等于}0.8GeV在计算核子{CLOSE_QUOTE}S海夸克分布时起主导作用。这个值接近QCD微扰演化开始的尺度，这进一步表明了高能过程中围绕核子的介子云物理图像的适用性的局限性。{版权所有}{1996年美国物理学会。}
We address the question of whether the nucleon{close_quote}s nonperturbative antiquark sea can be attributed entirely to its virtual meson cloud and, in essence, whether there exists a smooth transition between hadronic and quark-gluon degrees of freedom. We take into account contributions from {pi} and {ital K} mesons and compare them with the nucleon{close_quote}s antiquark distributions which serve as nonperturbative inputs to the QCD evolution equations. While the agreement of our calculations with data-based parametrizations is satisfactory and scale independent for the flavor-breaking share of the nucleon{close_quote}s antiquark sea, the flavor singlet component is quite poorly described. We find that large meson loop momenta, {parallel}{ital k}{parallel}{approx_equal}0.8 GeV, dominate in the calculation of the nucleon{close_quote}s sea quark distributions in the meson cloud model. This value is close to the scale where perturbative QCD evolution starts, which further indicates the limitations of the applicability of the physical picture of a meson cloud around the nucleon in high-energy processes. {copyright} {ital 1996 The American Physical Society.}