论文标题
关于稀有K和B衰减分支比率的标准模型预测：2022
On the Standard Model Predictions for Rare K and B Decay Branching Ratios: 2022
论文作者
论文摘要
In this decade one expects a very significant progress in measuring the branching ratios for several rare $K$ and $B$ decays, in particular for the decays $K^+\toπ^+ν\barν$, $K_L\toπ^0ν\barν$, $B_s\toμ^+μ^+$ and $B_d\toμ^+μ^+$.在理论方面，在过去的三十年中，在计算这些分支比率方面取得了非常重大的进展，最近以相当精确的SM预测对它们实现了最终的进展。不幸的是，有些论文仍然引用了$ k^+\toπ^+ν\barν$和$ k_l \toπ^0ν\barν$的结果，我们在2015年提出。它们显然是过时的。类似的评论适用于$ b_ {s，d} \toμ^+μ^ - $的预测。在本说明中，我想再次强调，鉴于$ v_ {cb} $的各种确定之间的紧张局势在树级衰减中，目前，可以通过消除$ | \ varepsilon_k | $ n $ |，$Δmm，$ | $ nive ckm参数来获得有关分支比率的唯一可信赖的SM预测。 $ s_ {ψk_s} $，在SM中进行了评估。在这种情况下，我对一些计算机代码从业人员的陈述感到惊讶，这些陈述在此策略中设定了这四个$ΔF= 2 $可观察到其实验值是一个假设。该策略的目的不是要使SM拟合，而是要预测SM分支比率。在SM中，没有新物理（NP）对$ΔF= 2 $转换的贡献，也不需要对不存在NP的假设。此外，目前不需要NP同时描述$ | \ varepsilon_k | $，$Δm_s$，$Δm_d$和$ s_ {ψk_s} $上的非常精确的数据。此外，这种用于获得稀有衰减分支比率的真实SM预测的策略不会受到Hadronic不确定的污染，并且观察到在全球分析中经常使用的半副本衰变中的异常，正如最近在全球分析中所强调的那样（ARXIV：2209.03968）。
In this decade one expects a very significant progress in measuring the branching ratios for several rare $K$ and $B$ decays, in particular for the decays $K^+\toπ^+ν\barν$, $K_L\toπ^0ν\barν$, $B_s\toμ^+μ^+$ and $B_d\toμ^+μ^+$. On the theory side a very significant progress on calculating these branching ratios has been achieved in the last thirty years culminating recently in rather precise SM predictions for them. It is then unfortunate that some papers still cite the results for $K^+\toπ^+ν\barν$ and $K_L\toπ^0ν\barν$ presented by us in 2015. They are clearly out of date. Similar comments apply to predictions for $B_{s,d}\toμ^+μ^-$. In this note I want to stress again that, in view of the tensions between various determinations of $V_{cb}$ in tree-level decays, presently, the only trustable SM predictions for the branching ratios in question can be obtained by eliminating their dependence on the CKM parameters with the help of $|\varepsilon_K|$, $ΔM_s$, $ΔM_d$ and $S_{ψK_S}$, evaluated in the SM. In this context I am astonished by statements made by some computer code practitioners that setting in this strategy these four $ΔF=2$ observables to their experimental values is an assumption. The goal of this strategy is not to make an overall SM fit but to predict the SM branching ratios. In the SM there are no new physics (NP) contributions to $ΔF=2$ transitions and no assumption on the absence of NP is needed. Moreover, presently NP is not required to describe simultaneously the very precise data on $|\varepsilon_K|$, $ΔM_s$, $ΔM_d$ and $S_{ψK_S}$. This strategy for obtaining true SM predictions for rare decay branching ratios is moreover not polluted by hadronic uncertainies and observed anomalies in semi-leptonic decays used often in global analyses as stressed recently in (arxiv: 2209.03968).
