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arXiv 2005.08550hep-phnucl-exnucl-th
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$N_c$手征大微扰理论中$π^0$、$η$和$η'$的双光子衰变和跃迁形状因子

Two-photon decays and transition form factors of $π^0$, $η$, and $η'$ in large-$N_c$ chiral perturbation theory

Patricia Bickert, Stefan Scherer

发表信息：
Phys. Rev. D 102, 074019 (2020)
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摘要：

本文在$N_c$手征微扰理论的单圈水平上计算了$P\to γ^{(\ast)}γ^{(\ast)}$过程，其中$P=π^0,\ η,\ η'$，达到并包括次-次-首阶（NNLO）。结果在LO、NLO和NNLO下依次进行数值评估。出现的低能常数通过拟合现有的实验数据来确定。我们研究了到实光子的衰减宽度、单虚跃迁形状因子和$P\toγl^+l^-$的宽度，其中$l=e,\ μ$。此外，我们提供的过渡形状因子的斜率和曲率的结果。

英文摘要：

We present a calculation of $P\to γ^{(\ast)}γ^{(\ast)}$ processes, where $P=π^0,\ η,\ η'$, at the one-loop level up to and including next-to-next-to-leading order (NNLO) in large-$N_c$ chiral perturbation theory. The results are numerically evaluated successively at LO, NLO, and NNLO. The appearing low-energy constants are determined through fits to the available experimental data. We investigate the decay widths to real photons, the single-virtual transition form factors, and the widths of $P\toγl^+l^-$, where $l=e,\ μ$. Furthermore, we provide results for the slopes and curvatures of the transition form factors.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

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