Categorization of two-loop Feynman diagrams in the O(α~2) correction to e~+e~-→ ZH

The e~+e~-→ZH process is the dominant process for the Higgs boson production at the future Higgs factory.In order to match the analysis on the Higgs properties with highly precise experiment data,it will be crucial to include the theoretical prediction to the full next-to-next-to-leading order electroweak effect in the production rateσ(e~+e~-→ZH).In this inspiring work,we categorize the two-loop Feynman diagrams of the O(α~2) correction to e~+e~-ZH into 6 categories according to relevant topological structures.Although 25377 diagrams contribute to the O(a~2) correction in total,the number of the most challenging diagrams with seven denominators is 2250,which contain only 3 12 non-planar diagrams with 155 independent types.This categorization could be a valuable reference for the complete calculation in future.