论文标题
增强$ z'$型号中直接$ cp $不对称性
Enhancement of Direct $CP$ asymmetry in $Z'$ models
论文作者
论文摘要
我们认为$ cp $ - 抗化$ z'$型号以$ b \ to s \ ell \ ell $衰减为异常。使用Lepton风味普遍性（LFU）违反比率的更新约束，$ b \ tosμμ$ $ $ $ $ $ CP $ conserving和$ cp $ - viol-violation observables，$ b_s- \ bar {b} _s $ c} _s $混合和中性群体的最喜欢的$ z'$ z'$ z'$ z'$ z' $ c_9^{\ rm np} <0 $和$ c_9^{\ rm np} = -c_ {10}^{\ rm np} $。我们表明，直接$ cp $不对称的预测$ a_ {cp} $ in $ b^+ \ to k^+μ\，μ$损失接近$ c \ bar {c} $ resonance区域，可用于检测新的$ cp $ after $ 1 $ coupling $ coupling $ 1 \ $ 1 \ $ coupled $ of of of of of z'方案$ c_9^{\ rm np} <0 $允许在$ q^2 = [8,9] \，\ rm {gev^2} $ bin中的集成$ a_ {cp} $增强，最高$ \ $ \ pm pm 10 \％$，以及$ q^2 = [$ q^2 = [6,7,7] 5 \％$。我们发现，对于$ j/ψ$共振的阶段的负值，尽管在$ z'$模型中可以增强这种增强，从而生成场景$ c_9^{\ rm np} = -c_ {\ c_ {10}^{\ rm np} $，但最受欢迎的参数pactor parameter space prefers prefers prefers prefers prefers Prefers of $ a_ _ _ = cp} $。因此，这些垃圾箱中直接$ CP $不对称的未来测量可能会限制违反新$ CP $的大小，并有助于区分$ z'$型号的两个类别。
We consider $CP$-violating $Z'$ models to account for the anomalies in $b \to s \ell \ell$ decays. Using the updated constraints from lepton flavor universality (LFU) violating ratios, $b \to s μμ$ $CP$-conserving and $CP$-violating observables, $B_s-\bar{B}_s$ mixing and neutrino trident we obtain the favored parameter space of two classes of $Z'$ models generating the `1D' new physics scenarios with $C_9^{\rm NP} <0$ and $C_9^{\rm NP} = -C_{10}^{\rm NP}$. We show that the predictions of direct $CP$ asymmetry $A_{CP}$ in $B^+ \to K^+ μ\, μ$ decays close to the $c \bar{c}$ resonance region can be used to detect the presence of new $CP$ violating phases in the $Z'$ couplings.The favored $1\,σ$ parameter space of $Z'$ models generating the scenario $C_9^{\rm NP} <0$ allows for an enhancement in the integrated $A_{CP}$ in $q^2 =[8,9]\,\rm{GeV^2}$ bin up to $\pm 10\%$ and in the $q^2 =[6,7]\,\rm{GeV^2}$ bin up to $\pm 5\%$. We find that for a negative value of the phase of $J/ψ$ resonance, although such an enhancement is possible in $Z'$ models generating the scenario $C_9^{\rm NP} = -C_{10}^{\rm NP}$, the favored parameter space prefers only positive values of $A_{CP}$. Hence, a future measurement of direct $CP$ asymmetry in these bins can potentially constrain the size of new $CP$ violating phases, and help in distinguishing between the two classes of $Z'$ models.
