论文标题
$ k^0- \ bar {k}^0 $混合的三杆效效果
Three-pion effects in $K^0-\bar{K}^0$ mixing
论文作者
论文摘要
中性kaon和反kaon之间的混合速率（$ k^0- \ bar {k}^0 $）在某种程度上由远程矩阵元素给出，并用两个弱的汉密尔顿式插入被物理，minkowski时间演变分开。对于物理夸克质量，kaon质量位于两杆和三杆阈值之上，结果，该长距离矩阵元素从中间的壳上$2π$和$3π$状态获得了贡献。这些贡献无法轻易在有限的欧几里得时空中捕获，这意味着无法通过晶状体QCD直接访问此类矩阵元素。在本演讲中，我们提出了一种合并数量的策略，该策略可以在数值晶格QCD计算中提取，以便重现$ k^0- \ bar {k}^0 $的物理，无限量的远程幅度。相对于已发表的工作，关键的新颖性是，我们完全包括以前被忽略的三粒子状态的影响。该策略建立在具有两粒子中间状态的远程矩阵元素的现有形式主义上，以及相对论场理论的有限量形式主义，用于提取三个hadron弱的衰减。
The rate of mixing between a neutral kaon and an anti-kaon ($K^0-\bar{K}^0$) is given, in part, by a long-range matrix element, defined with two insertions of the weak Hamiltonian separated by physical, Minkowski time evolution. For physical quark masses, the kaon mass lies above the two- and three-pion thresholds and, as a result, this long-range matrix element receives contributions from intermediate on-shell $2π$ and $3π$ states. These contributions cannot easily be captured in a finite Euclidean spacetime, meaning that such matrix elements are not directly accessible via lattice QCD. In this talk, we present a strategy for combining quantities that can be extracted in numerical lattice QCD calculations in order to reproduce the physical, infinite-volume long-range amplitude for $K^0-\bar{K}^0$. The key novelty relative to published work is that we fully include the effects of three-particle states that were previously neglected. The strategy is built on existing formalism for long-range matrix elements with two-particle intermediate states, together with the relativistic-field-theory finite-volume formalism for extracting three-hadron weak decays.
