Precision Study On The Production And Decay Of Charged Higgs Bosons At High Energy Colliders

In 2012,the 125 GeV Higgs boson was discovered by ATLAS and CMS collabora-tions at CERN.Although all the particles in the standard model(SM)were found,there are many phenomena in particle physics which cannot be explained under the frame-work of the standard model,such as the neutrino oscillation,fine tuning,dark matter,dark energy and so on.At present,the central tasks of high energy physics are testing the SM more precisely and searching new physics beyond the SM.As the accumulation of the experimental data,the statistical error will decrease.In order to match the accu-rate results of experiments,the theoretical predictions also need to be provided at the same level.Thus,we should consider the effects of high order perturbative corrections,resummation,PDF uncertainty and scale uncertainty.In the high order perturbative calculation,the calculation of multi-loop Feynman integrals is an essential part.In this paper,we focus on the multi-loop calculation in precision calculation.In the aspect of searching new physics,the Higgs sector plays a critical role in studying the electro-weak symmetry breaking and the origin of mass.The Higgs extensions provide some new ideas in searching exotic particles beyond the standard model.Since the existence of charged Higgs is an important trait of many Higgs extensions,investigation on the properties of charged Higgs boson at high energy colliders is very important.We focus on the two Higgs doublet model(THDM)and Georgi-Machacek(GM)model in this paper.THDM is a simple Higgs extension of the SM,which contains two Higgs doublets.Despite the simplicity of THDM,it also provides rich phenomena,such as the existence of charged Higgs boson,CP-violation,candidate of dark matter and so on.We investigate the charged Higgs associated production at high energy lepton colliders.We also study the constraints of THDM and provide a benchmark scenario in low charged Higgs mass and small tan ? region.In order to give a precise prediction of the e+e-?H±W(?)process,the two-loop QCD corrections are taken into consid-eration in this paper.As a Higgs extension of the SM,the Higgs sector of GM model contains one real triplet and one complex triplet besides the doublet of the SM.Com-paring with the extensions which contain only doublet,there are some distinct features of GM model,such as the existence of doubly charged Higgs boson,loose constraints from electro-weak precision measurements.In this paper,we study in detail the doubly charged Higgs boson associated with a SM Higgs production via vector boson fusion at hadron colliders,i.e.pp?H±±h0jj.we also discuss the constraints of GM model and the benchmark scenario.To give a precise prediction,we investigate the QCD cor-rections at next-to-leading order and the scale uncertainties.And we analyse the decay of doubly charged Higgs boson.In the aspect of calculating the multi-loop Feynman diagrams,we develop some computing methods including the sector decompositions method and differential equa-tions method.In this paper,we correct some errors in the existing programs with sector decompositions method and improve their efficiency with some numerical calculation methods.We also study and realize a systematic computing program with differential equations method.Comparing the programs with sector decompositions method,our program is much faster and save computing resource.We apply our program in the in-vestigation on the charged Higgs associated production at high energy electron positron colliders.