长距离对风味变化过程的贡献
Long-distance contributions to flavour-changing processes
摘要：
在味物理或强子结构研究中的标准晶格计算是基于强子态或真空之间的局部复合算子的矩阵元的评估。在这次演讲中，我将讨论旨在计算长距离的发展，因此非本地，对这些过程的贡献。特别地，我考虑了$K_L$ - $K_S$质量差$Δm_K=m_{K_L}-m_{K_S}$和稀有K介子衰变过程$K\toπ\ell^+\ell^-$的振幅的计算，其中轻子$\ell=e$或$μ$。晶格计算的长距离贡献的间接$CP$违反参数$ε_K$和罕见的衰变$K\toπν\barν$也开始。最后，我讨论的可能性包括$O(α)$电磁效应的轻子和半轻子衰变宽度的计算，其中的新功能是红外发散的存在。这意味着，在最终状态下的实光子过程对宽度的贡献必须与在振幅上的虚光子过程相结合，以便通过布洛赫-诺德西克机制消除红外发散。我提出了一个建议的程序晶格计算的$O(α)$的贡献与控制的红外发散的取消。
英文摘要：
Standard lattice calculations in flavour physics or in studies of hadronic structure are based on the evaluation of matrix elements of local composite operators between hadronic states or the vacuum. In this talk I discuss developments aimed at the computation of long-distance, and hence non-local, contributions to such processes. In particular, I consider the calculation of the $K_L$-$K_S$ mass difference $Δm_K=m_{K_L}-m_{K_S}$ and the amplitude for the rare-kaon decay processes $K\toπ\ell^+\ell^-$, where the lepton $\ell=e$ or $μ$. Lattice calculations of the long-distance contributions to the indirect $CP$-violating parameter $ε_K$ and to the rare decays $K\toπν\barν$ are also beginning. Finally I discuss the possibility of including $O(α)$ electromagnetic effects in computations of leptonic and semileptonic decay widths, where the novel feature is the presence of infrared divergences. This implies that contributions to the width from processes with a real photon in the final state must be combined with those with a virtual photon in the amplitude so that the infrared divergences cancel by the Bloch-Nordsieck mechanism. I present a proposed procedure for lattice computations of the $O(α)$ contributions with control of the cancellation of the infrared divergences.
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。
