Exploring HVV amplitudes with CP violation using decomposition and the on-shell scattering amplitude method  

作　　者：冯柯尧 万霞 王由凯 邬超 Ke-Yao Feng;Xia Wan;You-Kai Wang;Chao Wu(School of Physics and Information Technology,Shaanxi Normal University,Xi'an 710119,China;CAS Key Laboratory of Theoretical Physics,Institute of Theoretical Physics,Chinese Academey of Sciences,Beijing 100190,China)

机构地区：[1]School of Physics and Information Technology,Shaanxi Normal University,Xi'an 710119,China [2]CAS Key Laboratory of Theoretical Physics,Institute of Theoretical Physics,Chinese Academey of Sciences,Beijing 100190,China

出　　处：《Chinese Physics C》2023年第3期67-83,共17页中国物理C（英文版）

基　　金：Supported by the National Natural Science Foundation of China(11847168);the Fundamental Research Funds for the Central Universities of China(GK202003018);the Natural Science Foundation of Shannxi Province,China(2019JM-431,2019JQ-739)。

摘　　要：CP violation may play an important role in baryogenesis in the early universe and should be examined comprehensively at colliders.We study the CP properties of HVV vertexes between Higgs and gauge boson pairs by defining a CP violation phase angle,which indicates the mixture of CP-even and CP-odd Higgs states in HVV in new physics.A series of HVV amplitudes,H→γγ,H-→V→γtt,and H→VV-→4f,with a CP phase angle are studied systematically to explicitly explain why CP violation can only be probed independently in the 4t pro-cess.We obtain a novel amplitude decomposition relation that illustrates that if two preconditions(multilinear mo-mentum dependent vertexes,and the current J_(μ) of V→l^(+)l^(-)is formally proportional to a photon's polarization vec-tor)are satisfied,a higher-point amplitude can be decomposed into a summation of a series of lower-point amp-litudes.As a practical example,the amplitude of the H→γV-→γtt and H→VV→4t processes can be decom-posed into a summation of many H→γγ amplitudes.We calculate these amplitudes in the framework of the on-shell scattering amplitude method,considering both massless and massive vector gauge bosons with the CP viola-tion phase angle.The above two approaches provide consistent results and clearly reveal the CP violation ξ depend-ence in the amplitudes.

关 键 词：HIGGS scattering amplitude CP violation 

分 类 号：O572.34[理学—粒子物理与原子核物理]