Study Of Higher-Order P QCD Corrections To The Higgs Hadronic Decay Widths Under The Momentum-space Subtraction Scheme

With the operation of the Large Hadron Collider in Europe,the data of high energy physics experiments have become more and more accurate,which urgently requires theorists to improve the accuracy of theoretical predictions.At present,people have found that many standard model predictions of high energy physics processes are quite different from experimental data.Therefore,it is necessary to confirm whether this difference is a theoretical error of the standard model or because of new physics beyond the standard model.The innovation of this article is that the internationally recognized the principle of maximum conformality(PMC)approach will be used to analyse the properties of higher-order pQCD corrections to the Higgs hadronic decay widths.We have found that the PMC approach can be used to eliminate the uncertainty of the renormalization scale and renormalization scheme.In additional,the PMC approach eliminate the renormalon which is divergence,and improves the convergence of pQCD,then enhance the theoretical prediction accuracy of perturbation theory.Using the recently obtained the decay width of Higgs to double gluon at ?s6-order QCD correction,we combined the PMC multi-scale setting approach to discuss the perturbation of the decay width in detail.The PMC multi-scale-setting utilizes the renormalization group equation to determine the optimal running behavior of each order of strong coupling constants and provides a guided method to eliminate the conventional renormalization scheme and the uncertainty of the renormalization scale.After adopting this approach,the expansion coefficients of each order in the perturbation sequence are transformed into conformal sequences that have nothing to do with the renormalization scheme,thereby solving the dependence of the renormalization scheme under the conventional scheme;due to the determined effective strong coupling has nothing to do with the choice of the renormalization energy scale,and this method can simultaneously obtain theoretical predictions that have nothing to do with the choice of the renormalization energy scale.The numerical results in this paper is consistent with the above mentioned properties of PMC approach.Although the ambiguity of the renormalization scale under PMC multi-scale-setting has been removed,the unknown higher-order terms lead to the residual scale ambiguity of PMC prediction.Using higher accuracy results(up to ?s6 corrections)can further reduce the dependence of the PMC multi-scale method found in the previous work on the residual scale under ?s5-order corrections.In order to reduce the residual scale dependence,we adopt the PMC single-scale-setting approach to reanalyze the decay width of Higgs to double gluon.We combined the PMC single-scale-setting approach to analyze the pQCD gauge dependence in the momentum-space subtraction scheme(MOM)in detail.The PMC single-scale-setting approach is the same as the multi-scale-setting approach,which is based on the renormalization group equation to determine the value of the strong coupling constant of the high-energy physical process,but it only needs to determine one effective strong coupling constant of the whole process.Therefore,PMC single-scale-setting approach can be greatly reduced in the processing,and the determined effective PMC scale has a uniform high precision,thereby eliminating the uncertainty of the renormliazation scale while greatly reducing the dependence of residual scale due to unknown higher-order terms.The MOM scheme is one of the renormalization schemes that people often use in pQCD theoretical calculations.Compared with the renormalization scheme of dimensional regulation,it has its own advantages,especially for the decay of Higgs particles to double gluons.The MOM scheme can avoid the problem of distinguishing non-conformal items encountered during processing under the MS scheme.As we all know,the theoretical prediction under the dimensional renormalization scheme does not have the dependence of the gauge parameters,but the prediction under the MOM scheme has obvious dependence of the gauge parameters.Using the Higgs particle decay to gluon process,we conducted a detailed analysis of the gauge parameter dependence in the perturbation QCD prediction under the MOM scheme.We selected five asymmetric MOM schemes(such as mMOM,MOMh,MOMq,MOMg and MOMgg scheme)and three completely symmetrical MOM schemes(such as MOMggg,MOMh and MOMq scheme)as reference schemes for discussion.It is found that the decay width of the Higgs particle decay to double gluon weakly relies on the choice of the MOM scheme,which is consistent with the nature of the renormalization group invariance.We also found that the gauge dependence under the MOMgg scheme is very weak.It is the smallest gauge dependence in the MOM scheme mentioned.Also,the gauge dependence can not be removed by the PMC scale-setting method,and gauge dependence cannot be eliminated under the traditional scale-setting.Regardless of whether the PMC energy standard-setting method or the conventional scale-setting method is adopted,the gauge dependence will not be weakened with the improvement of the calculation accuracy of pQCD.Nevertheless,the gauge dependence of the specification parameters in the interval is relatively small.