论文标题
用kaon衰变$ k \toππ\！\ not \！\！e $探索新物理
Probing new physics with the kaon decays $K\toππ\!\not\!\!E$
论文作者
论文摘要
Na62实验对稀有Kaon衰减$ K^+\toπ^+barν$的最新搜索为其提供了证据，其分支分数与标准模型的预测一致。新结果意味着，在这种衰变中，$ν\barν$对表现为缺失的能量（$ \ \！\！e $），不再是可能的新物理学的空间，因此它有助于基础四方面$ s \ d \！\！\ not \！\！\！\！尽管如此，我们指出的是，主要是由$ k \toππ\！\ not \！\！e $模式中的相应运算符引起的标准模型超出标准模型的明显表现，目前只有最小的经验详细信息。我们特别发现，这种新物理学可能会增强$ k_l \toπ^0π^0 \！\ not \！\！e $的分支分数，以达到其当前实验上限的值以及$ k^+\toπ^+toπ^+π^0 \！\！\！\！\！\！\！\！\！ $ k_l \toπ^+π^ - \！\ not \！\！因此，在KAON设施（例如Koto和Na62或将来的）中对这些衰减的任务可以提供有价值的信息，以补充从$ k \toπ\！\！\ not \！\！e $中获得的信息。
The latest search for the rare kaon decay $K^+\toπ^+ν\barν$ by the NA62 experiment has produced evidence for it with a branching fraction consistent with the prediction of the standard model. The new result implies that in this decay, with the $ν\barν$ pair appearing as missing energy ($\not\!\!E$), the room for possible new physics is no longer sizable and that therefore its contributions to underlying four-particle $s\to d\!\not\!\!E$ operators with parity-even $ds$ quark bilinears have become significantly constrained. Nevertheless, we point out that appreciable manifestations from beyond the standard model induced by the corresponding operators with mainly parity-odd $ds$ quark bilinears could still occur in $K\toππ\!\not\!\!E$ modes, on which there are only minimal empirical details at present. We find in particular that new physics of this kind may enhance the branching fraction of $K_L\toπ^0π^0\!\not\!\!E$ to values reaching its current experimental upper limit and the branching fractions of $K^+\toπ^+π^0\!\not\!\!E$ and $K_L\toπ^+π^-\!\not\!\!E$ to the levels of $10^{-7}$ and $10^{-6}$, respectively. Thus, quests for these decays in existing kaon facilities such as KOTO and NA62 or future ones could provide valuable information complementary to that gained from $K\toπ\!\not\!\!E$.
