论文标题
削减有关$ cp $违反量子动力学理论的圆柱和简化的图解方法的规则
Cutting rules on a cylinder and simplified diagrammatic approach to $CP$ violation in quantum kinetic theory
论文作者
论文摘要
我们简要解释了一种新的图解方法，用于在$ cp $不对称反应率中加入量子玻尔兹曼方程。在热平衡中，由于$ s $ -matrix Unitarity和$ cpt $不变性，不对称必须准确取消。此类取消在零温度的前阶计算中易于跟踪。但是，考虑中等效果需要修改繁殖者的壳部分，因此需要违反$ cp $的费率。在文献中，在某个近似中采用了非平衡场理论的实时形式，在不对称源项中的统计因素的正确形式已获得。我们证明，可以通过将无限的零温度不对称序列求和可以获得相同的结果。这些源自在圆柱表面上绘制的前图的插曲，而热校正来自其传播器的绕组。该过程完全是图形的，并且$ CPT $和Unitarity取消是针对热校正的反应速率不对称的。实现的简化是我们工作的主要重点。还将讨论高阶校正中红外有限性的方面。
We briefly explain a novel diagrammatic method for including thermal corrections in $CP$ asymmetric reaction rates entering the quantum Boltzmann equation. In thermal equilibrium, the asymmetries have to cancel precisely due to the $S$-matrix unitarity and $CPT$ invariance. Such cancelations are easy to track in zero-temperature leading-order calculations. However, accounting for medium effects requires modification of the on-shell part of propagators and, consequently, the $CP$ violating rates. In the literature, the correct form of the statistical factors in the asymmetry source term has been obtained employing the real-time-formalism of non-equilibrium field theory in a certain approximation. We demonstrate that the same results can be obtained by summing an infinite sequence of zero-temperature asymmetries. Those are derived from cuttings of forward diagrams drawn on a cylindrical surface, while thermal corrections come from windings of their propagators. The procedure is entirely diagrammatic, and the $CPT$ and unitarity cancelations are formulated for thermally corrected reaction rate asymmetries. The simplification achieved is the primary focus of our work. The aspect of infrared finiteness in higher-order corrections will also be discussed.
