论文标题
另一个SMEFT故事：$ z^\ prime $面对$ \ varepsilon'/\ varepsilon $，$Δm_k$和$ k \toπν\barν$
Another SMEFT Story: $Z^\prime$ Facing New Results on $\varepsilon'/\varepsilon$, $ΔM_K$ and $K\toπν\barν$
论文作者
论文摘要
最近，RBC-UKQCD Lattice Collaboration为标准模型（SM）中的比率$ \ VAREPSILON'/\ VAREPSILON $相关的HADRONIC矩阵元素提供了新的结果。借助Wilson系数和Isospin Breaking效果的当前知识，对于$ \ Varepsilon'/\ Varepsilon $，仍然有很大的空间（NP）贡献可以提高或抑制此比率以同意数据。 $ k^0- \ bar k^0 $质量差$Δm_k$从rbc-ukqcd的新SM值在抑制$Δm_k$所需的NP上的$2σ$的另一方面为$2σ$。同时，来自Na62的$ K^+\rightArrowπ^+barν$的最新结果，以及$ k_ {l} \rightArrowπ^0ν\barν$来自koto的barbarν$仍然允许NP的重要贡献。我们指出，NP对$ΔM_K$的抑制需要存在新的CP-violation阶段，对$ k \toπν\barν$，$ k_s \toμ^+μ^ - $^$^$ and $ k_l \toπ^0 \ ell^ell^ell^el^+ell^el^ell^ell^ell^$衰减。考虑到SMEFT中的$ z^\ prime $ -Scenario，我们分析了所有这些观察处对数据仍然允许的NP大小的依赖性，该数据仍然允许$ \ varepsilon'/\ varepsilon $。 $ \ Varepsilon'/\ Varepsilon $的NP QCD企鹅场景被SMEFT重生的组效应排除在$ \ varepsilon_k $中，以便NP效应$ \ VAREPSILON'/\ VAREPSILON $受Electroweak pengeNement。我们还首次调查是否存在违反风味耦合的重型$ z^\ prime $是否可以通过Yukawa Rentoralization templect产生由SM $ Z $ -BOSON介导的FCNC。结果原来非常有趣。
Recently the RBC-UKQCD lattice collaboration presented new results for the hadronic matrix elements relevant for the ratio $\varepsilon'/\varepsilon$ in the Standard Model (SM). With the present knowledge of the Wilson coefficients and isospin breaking effects there is still much room for new physics (NP) contributions to $\varepsilon'/\varepsilon$ which could both enhance or suppress this ratio to agree with the data. The new SM value for the $K^0-\bar K^0$ mass difference $ΔM_K$ from RBC-UKQCD is on the other hand by $2σ$ above the data hinting for NP required to suppress $ΔM_K$. Simultaneously the most recent results for $K^+\rightarrowπ^+ν\barν$ from NA62 and for $K_{L}\rightarrowπ^0ν\barν$ from KOTO still allow for significant NP contributions. We point out that the suppression of $ΔM_K$ by NP requires the presence of new CP-violating phases with interesting implications for $K\toπν\barν$, $K_S\toμ^+μ^-$ and $K_L\toπ^0\ell^+\ell^-$ decays. Considering a $Z^\prime$-scenario within the SMEFT we analyze the dependence of all these observables on the size of NP still allowed by the data on $\varepsilon'/\varepsilon$. The NP QCD penguin scenario for $\varepsilon'/\varepsilon$ is excluded by SMEFT renormalization group effects in $\varepsilon_K$ so that NP effects in $\varepsilon'/\varepsilon$ are governed by electroweak penguins. We also investigate for the first time whether the presence of a heavy $Z^\prime$ with flavour violating couplings could generate through top Yukawa renormalization group effects FCNCs mediated by the SM $Z$-boson. The outcome turns out to be very interesting.
