论文标题

带有Minkowskian Dynamics的PARTON分布功能

The parton distribution function in a pion with Minkowskian dynamics

论文作者

de Paula, W., Ydrefors, E., Nogueira, J. H. Alvarenga, Frederico, T., Salmè, G.

论文摘要

首次从Minkowski空间中的动力学方程的溶液中首次获得PARTON分布。所采用的方程是具有梯子内核的均匀的贝尔盐,用i)构成夸克和gluons的自由度来描述,ii)扩展的夸克 - 格鲁恩顶点。 QUARK和GLUON的质量以及相互作用 - vertex量表已在晶状体QCD计算建议的范围内选择,并进行了校准以重现Pion质量和衰减常数。除了完整的Parton分布以外,我们还计算了来自光(光价波函数)的贡献,该函数对应于Pion态膨胀中最低的Fock成分。在使用有效电荷和LO分裂函数的演变应用后,列出了与提取的实验数据(有或没有重新调整效应)和在不同框架中获得的其他最新计算的详细和鼓舞人心的比较。有趣的是,在纵向摩托米特部分的广泛区域中,Parton分布函数在初始尺度上从Pion状态的较高的Fock组分中获得了相当大的贡献,同时正如预期的那样,在接近尾部的光线价分量占主导地位。此外,发现指数$ \ sim $ 3适用于以5.2 GEV的比例描述尾巴。

The parton distribution of the pion is obtained for the first time from the solution of a dynamical equation in Minkowski space. The adopted equation is the homogeneous Bethe-Salpeter one with a ladder kernel, described in terms of i) constituent quarks and gluons degrees of freedom, and ii) an extended quark-gluon vertex. The masses of quark and gluon as well as the interaction-vertex scale have been chosen in a range suggested by lattice QCD calculations, and calibrated to reproduce both pion mass and decay constant. Beside the full parton distribution, we have also calculated the contribution from the light-front valence wave function, corresponding to the lowest Fock component in the expansion of the pion state. After applying an evolution with an effective charge and a LO splitting function, a detailed and inspiring comparison with both the extracted experimental data ( with and without resummation effects) and other recent calculations obtained in different frameworks is presented. Interestingly, in a wide region of longitudinal-momentum fraction, the parton distribution function receives sizable contributions from the higher Fock-components of the pion state at the initial scale, while approaching the tail the light-front valence component dominates, as expected. Moreover, an exponent $\sim$ 3 is found suitable for describing the tail at the scale 5.2 GeV.

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