NNLO QCD Corrections to $D$-Wave Spin-Singlet Heavy Quarkonia Decay ${\eta }_{Q2}\to \gamma \gamma$ via the Principle of Maximum Conformality

Hua Zhou, Xing-Gang Wu, Qing Yu +1

In this paper, we perform a comprehensive study of the decay process ${\eta }_{Q2}\to \gamma \gamma$ for $D$-wave spin-singlet heavy quarkonia up to next-to-next-to-leading-order (NNLO) QCD correcti…