Precision Study Of Triple Gauge Boson Production And The Search For BSM Higgs Boson

After the Standard Model Higgs particle was discovered,the current development goal of high-energy physics mainly focuses on the search for new physics.The search for new physics can be carried out in two aspects:1.Precision test of the standard model,i.e.,more accurate results should be given theoretically and experimentally,in order to find subtle deviations between current theories and experiments;2.The living parameter space of various new physical models,and providing the phenomenology that may appear in the new physics under the constraints,so as to provide guidance for experiments to find new physical signals.Followed these two approaches,this paper studies the phenomenology of production of three gauge bosons and the production of new Higgs particles in the BSM.The precision study of the production of gauge bosons has always been one of the hotspots and emphases of high energy physics.The pair production of bosons have been reached NNLO QCD and NLO EW order,and the NLO EW correction of three gauge bosons production is currently studied.The gauge boson means W bosons,Z bosons and photons,and the precise study of its various forms of combinational pro-duction patterns is also being widely concerned.One of the main tasks of this paper is to precisely study the WW? at the NLO QCD+EW level with parton shower effect.Besides,many new models,such as the supersymmetric model,THDM,GM models have been proposed.The current LHC experiments have given a strict limit to the sur-vival space of these models.Another part of the paper is to scan the parameters of the GM model according to the current theoretical and experimental constraints,and ana-lyze the mechanism of production and decay of the heavy Higgs particle predicted in the model in detail and give its phenomenology.Meanwhile,in recent years,the ap-plication of machine learning has made great progress in the high energy physics,such as signal background analysis of new physics,quark identification,more efficient pa-rameter scanning and so on.This paper will also take the GM model as an example to demonstrate the application of deep learning in phenomenology of high energy physics.For example,the last part of this paper mainly discusses the possible resonant peak structure found near 18.4 GeV on CMS experimental group.The theoretical results are given based on the hypothesis of pseudoscalar particle and scalar particle respectivelyThe innovation of this paper includes the following aspects:·The combination of the electroweak correction calculation and the QCD parton shower in the study of the production of the three gauge bosons was not consid-ered in most previous researchs,and the detailed analysis of the photon PDF on the process is also one of the important innovations.In the NLO fixed-order cal-culation,we adopted the phase-space splicing method to deal with the divergence caused by the real radiation process,and adopted the mixed scheme of FF pack-age and Denner in the five-point loop integral calculation.Meanwhile,we use the Frixion isolation method to give a reliable result to solve the photon/jet res-olution problem.The problem of t-quark resonance also arises in the calculation of the real radiation of the initial state of the b quark,and we solve this problem by assuming that the efficiency of b tagging is 100%.When calculating PDF un-certainties,we used a variety of PDF sets and compared them with each other,and found that the latest NNPDF and LUX PDF gave relatively little uncertainty.·In the study of the GM model,the decay modes of the heavy neutral Higgs particle is given for the first time,and its four main production modes are given along with the running curves of collision energy and Higgs mass.We find that the particle is mainly produced by gluon gluon fusion and vector boson fusion.It also decays into two fiveplet Higgs when the parameters allow,and the most important decay pattern is two vector bosons.We also study the phenomenology of these main mechanisms and give the parameter scanning of the whole model.·For the doubly charged Higgs boson and W associated production,we also use the deep neural network method to analyze signal and background.And the ad-vantage of this method is that it do not need to be designed a variety of conditions of the cut compared with traditional methods,we just need to input four momen-tum of final state particles,and parameterized neural network can be applied to the unknown parameter uncertainty.·For the theoretical explanation of the 18.4 GeV resonant peak,we give the gg?effective coupling by referring to the ggH coupling of the standard model,and make a reasonable estimation of the parameters in the effective coupling by the constraints given by the experiment.At last,we give the theoretical kinematic distribution of the final state.