标题： 非微扰修正在重求和截面中的应用 显示英文标题

标题： Nonperturbative Corrections in Resummed Cross Sections

摘要： 我们证明，在QCD中，大微扰修正的重求和会导致高能截面中的歧义，这些歧义被大动量尺度的幂次所抑制。 这些歧义是由红外重整子引起的，这是微扰QCD中重求和硬散射函数的一个普遍特征，尽管这些函数在微扰理论中逐阶是红外安全的。 与算符乘积展开的情况类似，红外重整子对系数函数的贡献可以被吸收进高维算符的定义中，这些算符引起在高能下被幂次抑制的非微扰修正。 抑制的强度由主要红外重整子的位置决定，该位置可以在重求和级数中明确识别。 然而与算符乘积展开不同的是，在因子化强子-强子散射和喷注截面中相关的算符通常在QCD中是非局域的，尽管它们可以在eikonalized夸克的有效理论中表示为局域算符。 在此背景下，我们验证并解释了包含Drell-Yan截面中$1/Q$修正以及$Q$对质量的存在的现象。 以类似的方式，我们在Drell-Yan过程的横向动量分布的影响参数空间中发现了$\exp(-b^2\ln Q)$修正以及$e^+e^-$湮灭。 我们还表明，基于锥的喷注截面的主要非微扰修正表现形式为$1/(Q\delta)$，其中$\delta$为喷注的开口角，$Q$为质心系能量。 显示英文摘要

摘要： We show that the resummation of large perturbative corrections in QCD leads to ambiguities in high energy cross sections that are suppressed by powers of large momentum scales. These ambiguities are caused by infrared renormalons, which are a general feature of resummed hard-scattering functions in perturbative QCD, even though these functions are infrared safe order-by-order in perturbation theory. As in the case of the operator product expansion, the contributions of infrared renormalons to coefficient functions may be absorbed into the definition of higher-dimensional operators, which induce nonperturbative corrections that are power-suppressed at high energies. The strength of the suppression is determined by the location of the dominant infrared renormalon, which may be identified explicitly in the resummed series. In contrast to the operator product expansion, however, the relevant operators in factorized hadron-hadron scattering and jet cross sections are generally nonlocal in QCD, although they may be expressed as local operators in an effective theory for eikonalized quarks. In this context, we verify and interpret the presence of $1/Q$ corrections to the inclusive Drell-Yan cross section with $Q$ the pair mass. In a similar manner, we find $\exp(-b^2\ln Q)$ corrections in the impact parameter space of the transverse momentum distributions of the Drell-Yan process and $e^+e^-$ annihilation. We also show that the dominant nonperturbative corrections to cone-based jet cross sections behave as $1/(Q\delta)$, with $\delta$ the opening angle of the jet and $Q$ the center of mass energy.