Total decay width of $H \to gg$ using the infinite-order scale-setting approach based on the intrinsic conformality

We make a detailed study on the properties of the total decay width of Higgs decay channel $H\to gg$ up to $\alpha_s^6$-order QCD corrections by using the newly suggested infinite-order scale-setting approach, which is based on the ideas of both the principle of maximum conformality and the intrinsic conformality. This approach is called as the PMC$_\infty$ approach. By using the PMC$_\infty$ approach, we observe that the conventional renormalization scale ambiguity in perturbative QCD calculation is eliminated and the residual scale dependence due to unknown higher-order terms can also be highly suppressed. We then obtain an accurate perturbative QCD prediction on the total decay width, e.g. $\Gamma (H \to gg)|_{\rm PMC_\infty} =336.42^{+7.01}_{-6.92}$ KeV, where the errors are squared averages of those from all the mentioned error sources.