In this paper, we present a new analysis on the P-wave charmonium annihilation into two photons up to next-to-next-to-leading order (NNLO) QCD corrections by using the principle of maximum conformality (PMC). The conventional perturbative QCD prediction shows strong scale dependence and deviates largely from the BESIII measurements. After applying the PMC, we obtain a more precise scale-invariant pQCD prediction, which also agrees with the BESIII measurements within errors, i.e. \(R={\Gamma _{\gamma \gamma }(\chi _{c2})} /{\Gamma _{\gamma \gamma }(\chi _{c0})}=0.246\pm 0.013\), where the error is for \(\Delta \alpha _s(M_\tau )=\pm 0.016\). By further considering the color-octet contributions, even the central value can be in agreement with the data. This shows the importance of a correct scale-setting approach. We also give a prediction for the ratio involving \(\chi _{b0, b2} \rightarrow \gamma \gamma \), which could be tested in future Belle II experiment.

在本文中，我们通过使用最大保形 (PMC) 原理，对P波珲蒙湮灭为两个光子进行了新的分析，直至达到次前次前次 (NNLO) QCD 校正。传统的微扰 QCD 预测显示出很强的尺度依赖性，并且很大程度上偏离了 BESIII 测量。应用 PMC 后，我们获得了更精确的尺度不变 pQCD 预测，这也与误差范围内的 BESIII 测量一致，即\(R={\Gamma _{\gamma \gamma }(\chi _{c2})} /{\Gamma _{\gamma \gamma }(\chi _{c0})}=0.246\pm 0.013\)，其中误差为\(\Delta \alpha _s(M_\tau )=\pm 0.016\ ). 通过进一步考虑颜色八位字节的贡献，甚至中心值也可以与数据一致。这表明了正确的规模设置方法的重要性。我们还对涉及\(\chi _{b0, b2} \rightarrow \gamma \gamma \)的比率进行了预测，这可以在未来的 Belle II 实验中进行测试。