论文标题
$π^0 $，$η$和$η'$ in-y-n_c $ chiral扰动理论
Two-photon decays and transition form factors of $π^0$, $η$, and $η'$ in large-$N_c$ chiral perturbation theory
论文作者
论文摘要
我们介绍了$ p \toγ^{（\ ast）}γ^{（\ ast）} $过程的计算，其中$ p =π^0，\η，\η'$，在一环级别上，包括近来的next to-next-next-next to-nlo-$ n _ c $ n_c $ n_c $ chiral pert pert pert chiral pert pert chiral pert chiral pert to-next to-next to-next-to-nlo pertertation。结果在LO，NLO和NNLO上连续评估结果。出现低能常数是通过与可用的实验数据拟合确定的。我们研究了对真实光子的衰减宽度，单一虚拟的过渡形式和$ p \toγl^+l^ - $的宽度，其中$ l = e，\μ$。此外，我们为过渡形式的斜率和曲率提供了结果。
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.
