论文标题
MUON电子向后散射：CET中端点奇点的一个典型示例
Muon-electron backward scattering: a prime example for endpoint singularities in SCET
论文作者
论文摘要
我们认为，向后方向上的能量振荡 - 电子散射可以看作是模板案例，以研究与端点差异相关的大对数重新召集，这些对数与端点差异相关，出现在有效的硬性分类过程中。虽然六十年代中期以来就知道，从QED校正恢复到振幅水平的修改贝塞尔功能的领先双对数，但软共线有效理论（SCET）中的现代配方显示出令人惊讶的复杂且迭代的端点卷积积分的模式。与底部Quark诱导的$ H \ toγγ$衰减相反，最近提出了重新归一化的分解定理，我们发现速度对数会产生近似近似分析指数的无限塔。这可以理解为基础$ 2 \ 2 $运动学的一般结果。使用共线矩阵元素的终点重构条件，我们展示了如何从“裸”分解定理中的数量之间的一致性关系中复制贝塞尔函数。
We argue that energetic muon-electron scattering in the backward direction can be viewed as a template case to study the resummation of large logarithms related to endpoint divergences appearing in the effective-theory formulation of hard-exclusive processes. While it is known since the mid sixties that the leading double logarithms from QED corrections resum to a modified Bessel function on the amplitude level, the modern formulation in Soft-Collinear Effective Theory (SCET) shows a surprisingly complicated and iterative pattern of endpoint-divergent convolution integrals. In contrast to the bottom-quark induced $h \to γγ$ decay, for which a renormalized factorization theorem has been proposed recently, we find that rapidity logarithms generate an infinite tower of collinear-anomaly exponents. This can be understood as a generic consequence of the underlying $2\to 2$ kinematics. Using endpoint refactorization conditions for the collinear matrix elements, we show how the Bessel function is reproduced in the effective theory from consistency relations between quantities in a "bare" factorization theorem.
