The Effect Of HZZ Anomalous Coupling On The Angular Distribution

There may be some parts in the vertices of HVV that are beyond the standard model.The study of the vertex Lorentz structure plays a key role in the exploration of new physics.In this paper,we use the method of spinor helicity amplitudes to calculate the amplitude of process gg? H?ZZ/WW? 2e2?/2e2ve and it is written in the MCFM package.Because the gg? H? ZZ? 2e2? process has a higher measurement accuracy in the experiment,we focus on the H? ZZ process.We add a new angle variable to MCFM and get the histogram of the angular distribution of the final state corresponding to each process.We simulate the signal processes of Higgs in the on-shell region and off-shell region,the interference between different signals,and the angular distribution of the interference between the signal and the box background.The angular distribution is used to find the anomalous coupling parts in the vertices.The first chapter introduces the motivation of studying the anomalous coupling of HZZ by angular distribution.The second chapter introduces the theoretical background of HZZ//HWW helicity amplitude calculation and MCFM.The third chapter introduces the current research progress,including the measurement of anomalous coupling coefficient and the research status of angular distribution,and points out the achievements and shortcomings of the current study of angular distribution.In the fourth chapter,we add the process of Beyond Standard Model(BSM)to MCFM.By defining new kinematics variables and writing them into the program,the angular distribution is simulated and the relationship between anomalous coupling and angular distribution is analyzed.Our main work falls into the following three areas1.The amplitudes of process gg?H?ZZ/WW? 2e2?/2e2ve with BSM vertices are calculated by using the spinor helicity amplitudes method,and the amplitudes of BSM cp-even and cp-odd are added into the MCFM package as new processes.2.The angle definition of Higgs production plane and decay plane is given,and the algorithm of these angles is added to the MCFM package,so that the angular distribution of the process can be obtained through the simulation of MCFM in the future research.3.We simulate the angular distribution of various signal processes,the interference between different signal processes,and the interference between signals and the gg? ZZ process without Higgs participation.We consider the influence of Higgs on-shell,off-shell,and case selection conditions on the angular distribution.We find that interference between the SM process and processes that include HZZ cp-odd vertices in Higgs onshell region affects the distribution of the overall process ?angle(the angle between the decay planes of the two vector bosons),i.e.the presence of interference will shift the peak position at ?=0 in the SM case.It is also found that the magnitude of the anomalous coupling coefficient of the CP-odd term will affect the degree of the offset.Finally,the relationship between the offset degree and the anomalous coupling coefficient of the CP-odd term is given.The interference between the CP-odd process and the background box process in the Higgs off-shell region will affect the overall angular distribution.This offset can be used to determine whether there is a possible CP-odd structure in the HZZ vertex.Compared with the study of total cross section,differential cross section can see more information.At present,it can not be determined experimentally whether there is a CP-odd part in the HZZ vertex.The study in this paper can provide a reference for future experimental measurements,and can better limit the anomalous coupling coefficients to explore new physics.