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arXiv 0709.2826hep-ph
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Sudakov在QCD中的重新定义

Sudakov resummation in QCD

Paolo Bolzoni

摘要:

在这篇博士论文中,我们分析和推广了重整化群方法,用于研究软共线多部分子发射引起的微扰膨胀中的大粒子的重定。特别是,我们提出了一个概括的这种方法,以促进光子生产。有趣的是,在软极限中,光子产生的特征是更复杂的双尺度运动学,但仍然可以简单地从相空间的一般运动学性质得出重新计算。此外,当多于一个颜色结构有助于固定顺序结果时,该方法不需要单独处理各个颜色结构。然而,在这里得到的remation公式原来是预测比以前的结果:这取决于这样一个事实,即这里既没有特定的因式分解性质的截面的软限制是假设,也不是软发射满足eikonal-like关系。我们还推导出了所有对数精度的简化公式,适用于所有的快速光子产生和Drell-Yan快度分布的值。我们发现,对于固定目标实验E866/NuSea,NLL重校准校正与NLO固定阶校正相当,并且对于获得与数据的一致性至关重要。最后,我们还概述了重整化群方法的未来可能的应用。

英文摘要:

In this PhD thesis, we analyze and generalize the renormalization group approach to the resummation of large logarithms in the perturbative expansion due to soft and collinear multiparton emissions. In particular, we present a generalization of this approach to prompt photon production. It is interesting to see that also with the more intricate two-scale kinematics that characterizes prompt photon production in the soft limit, it remains true that resummation simply follows from general kinematic properties of the phase space. Also, this approach does not require a separate treatment of individual colour structures when more than one colour structure contributes to fixed order results. However, the resummation formulae obtained here turn out to be less predictive than previous results: this depends on the fact that here neither specific factorization properties of the cross section in the soft limit is assumed, nor that soft emission satisfies eikonal-like relations. We also derive resumation formulae to all logarithmic accuracy and valid for all values of rapidity for the prompt photon production and the Drell-Yan rapidity distributions. We show that for the fixed-target experiment E866/NuSea, the NLL resummation corrections are comparable to NLO fixed-order corrections and are crucial to obtain agreement with the data. Finally we outline also possible future applications of the renormalization group approach.

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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