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arXiv 0909.0012hep-ph
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规范理论振幅的因式分解结构及其在LHC硬散射过程中的应用

Factorization Structure of Gauge Theory Amplitudes and Application to Hard Scattering Processes at the LHC

Jui-yu Chiu, Andreas Fuhrer, Randall Kelley, Aneesh V. Manohar

摘要:

利用软共线有效理论(SCET)对高能散射的电弱辐射修正的先前工作已经扩展到包括外部横向和纵向规范玻色子和希格斯玻色子。这允许一个计算辐射校正的所有部分子水平的硬散射振幅在标准模型NLL的顺序,包括QCD和电弱辐射校正,质量效应,和希格斯交换校正,如果高尺度匹配,这是抑制了两个订单的对数计数,并不包含大的日志,是已知的。有效理论的因式分解结构对无质量和有质量规范理论的高能规范理论振幅的形式有很强的约束,本文对此进行了详细的讨论。辐射修正可以表示为与过程无关的单粒子共线函数和一个普适软函数之和。给出了对qqbar-> W_T W_T,Z_T Z_T,W_L W_L,Z_L H和gg -> W_T W_T的辐射修正曲线图来说明我们的结果。纯电弱修正是大的,从12%,在500 GeV到37%,在2 TeV的横向W对生产,并迅速增加与能量。在大多数情况下,估计的理论不确定性的部分子(硬)截面是低于百分之一,小于不确定性的部分子分布函数(PDF)。本文讨论了SCET与其它因式分解方法的关系,并利用SCET导出了Sudakov形状因子、有质量和无质量规范理论、轻重外粒子的Magnea-Sterman方程。

英文摘要:

Previous work on electroweak radiative corrections to high energy scattering using soft-collinear effective theory (SCET) has been extended to include external transverse and longitudinal gauge bosons and Higgs bosons. This allows one to compute radiative corrections to all parton-level hard scattering amplitudes in the standard model to NLL order, including QCD and electroweak radiative corrections, mass effects, and Higgs exchange corrections, if the high-scale matching, which is suppressed by two orders in the log counting, and contains no large logs, is known. The factorization structure of the effective theory places strong constraints on the form of gauge theory amplitudes at high energy for massless and massive gauge theories, which are discussed in detail in the paper. The radiative corrections can be written as the sum of process-independent one-particle collinear functions, and a universal soft function. We give plots for the radiative corrections to q qbar -> W_T W_T, Z_T Z_T, W_L W_L, and Z_L H, and gg -> W_T W_T to illustrate our results. The purely electroweak corrections are large, ranging from 12% at 500 GeV to 37% at 2 TeV for transverse W pair production, and increasing rapidly with energy. The estimated theoretical uncertainty to the partonic (hard) cross-section in most cases is below one percent, smaller than uncertainties in the parton distribution functions (PDFs). We discuss the relation between SCET and other factorization methods, and derive the Magnea-Sterman equations for the Sudakov form factor using SCET, for massless and massive gauge theories, and for light and heavy external particles.

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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