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arXiv 1105.3676hep-ph
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双环半球软函数

The two-loop hemisphere soft function

Randall Kelley, Robert M. Schabinger, Matthew D. Schwartz, Hua Xing Zhu

摘要:

计算半球软函数的阶数为alpha_s^2。这是第一个计算到两个循环的多尺度软函数。结果与有效场论的预言完全一致。这就修正了双环推力和重喷流质量分布奇异部分的未知系数。有四个这样的系数,为2个事件的形状和2个颜色结构,这被证明是在良好的协议与以前的数值提取。软函数的渐近行为在CF CA颜色结构中具有双对数,这与非全局对数计算一致,但对于CF CA和CF TF nf颜色结构也具有子领先单对数。软函数的一般形式是复杂的,不能以简单的方式因式分解,并且与Hoang-Kluth定理不一致。精确半球软函数将从e+e-事件形状中去除α_s拟合上的一个不确定性来源。

英文摘要:

The hemisphere soft function is calculated to order alpha_s^2. This is the first multi-scale soft function calculated to two loops. The renormalization scale dependence of the result agrees exactly with the prediction from effective field theory. This fixes the unknown coefficients of the singular parts of the two-loop thrust and heavy-jet mass distributions. There are four such coefficients, for 2 event shapes and 2 color structures, which are shown to be in excellent agreement with previous numerical extraction. The asymptotic behavior of the soft function has double logs in the CF CA color structure, which agree with non-global log calculations, but also has sub-leading single logs for both the CF CA and CF TF nf color structures. The general form of the soft function is complicated, does not factorize in a simple way, and disagrees with the Hoang-Kluth ansatz. The exact hemisphere soft function will remove one source of uncertainty on the alpha_s fits from e+e- event shapes.

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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