论文标题
来自$ {e^+e^ - \toπ^0γ} $的HADRONIC真空极化和矢量 - 静脉共振参数
Hadronic vacuum polarization and vector-meson resonance parameters from ${e^+e^-\toπ^0γ}$
论文作者
论文摘要
我们研究了基于基础$π^0 \toγγ^*$过渡形式的分散性表示的反应$ e^+e^ - \toπ^0γ$。作为第一个应用，我们评估了$π^0γ$通道对Hadronic-Vacuum偏振校正对MUON的异常磁矩的贡献。我们发现$a_μ^{π^0γ} \ big | _ {\ leq 1.35 \，\ text {gev}} = 43.8（6）\ times 10^{ - 11} $，与数据直接集成数据的评估一致。其次，我们的拟合确定$ω$和$ ϕ $的共振参数。我们观察到与$ e^+e^ - \to3π$通道的良好一致性，并在拟合功能的非物理阶段通过$π^0γ$和$3π$在$ω$质量中的先前张力。结合两个频道，我们找到$ \ barm_Ω= 782.736（24）\，\ text {mev} $和$ \ bar m_Dcartion = 1019.457（20）\，\，\ text {mev} $，用于包括真空极化更正的群众。 $ ϕ $质量与PDG平均值完全吻合，PDG平均水平由$ \ bar k k $ channel的确定为主导，这表明与$3π$和$π^0γ$保持一致。对于$ω$质量，我们的结果是一致但更精确的，加剧的紧张局势，并通过从$2π$ Channel中提取的$ω$质量质量提取的$ω$质量。
We study the reaction $e^+e^-\toπ^0γ$ based on a dispersive representation of the underlying $π^0\toγγ^*$ transition form factor. As a first application, we evaluate the contribution of the $π^0γ$ channel to the hadronic-vacuum-polarization correction to the anomalous magnetic moment of the muon. We find $a_μ^{π^0γ}\big|_{\leq 1.35\,\text{GeV}}=43.8(6)\times 10^{-11}$, in line with evaluations from the direct integration of the data. Second, our fit determines the resonance parameters of $ω$ and $ϕ$. We observe good agreement with the $e^+e^-\to3π$ channel, explaining a previous tension in the $ω$ mass between $π^0γ$ and $3π$ by an unphysical phase in the fit function. Combining both channels we find $\bar M_ω=782.736(24)\,\text{MeV}$ and $\bar M_ϕ=1019.457(20)\,\text{MeV}$ for the masses including vacuum-polarization corrections. The $ϕ$ mass agrees perfectly with the PDG average, which is dominated by determinations from the $\bar K K$ channel, demonstrating consistency with $3π$ and $π^0γ$. For the $ω$ mass, our result is consistent but more precise, exacerbating tensions with the $ω$ mass extracted via isospin-breaking effects from the $2π$ channel.
