Precise Study Of Gauge-boson Coupling And Higgs-boson Associated Production At High-energy Colliders

Until now, the standard model (SM) is the most successful gauge theory based onthe gauge group SU(3)_C(?)SU(2)_L(?)U(1)_Y. Although most of its predictions havebeen perfectly coincident with the present precise experimental data, the Higgs bosonpredictedbytheSMhasnotbeendetected. TheSMstillhasmanytheoreticalproblems,such as the hierarchy problem, which make people believe that it is an effective theoryof some underlying theories in low energy and the new physics beyond the SM mustexist. Thus, the search for the Higgs boson and the new physics beyond the SM is theimportant task in current particle physics experiments at the running hadron colliders(LHC and Tevtron) and the proposed International Linear Collider (ILC).The hadron colliders and the ILC will complement each other in different collidingenvironments. Hadroncolliders,duetotheirhighcollisionenergyandthehighluminos-ity, are favorable for the discoveries of Higgs boson and new physics. Compared withhadron collider, striking features of linear collider are its much more clean backgroundand high accuracy of measurement. Therefore, ILC can carry out more detailed studiesof the new discoveries at hadron colliders. Thus, the hadron colliders and the ILC willconfirm mutually the discoveries of new physics and jointly promote the developmentof particle physics.The investigation of gauge-boson coupling is one of the important ways to detectthe new physics. If the experimental data do not well coincide with the SM theoret-ical predictions, the new physics will exist. The direct study of quartic gauge-bosoncouplings requires the investigation of the processes involving at least three final gaugebosons. In this paper, we study the complete one-loop electroweak (EW) corrections totheproductionofthreeZ0bosonsintheframeworkoftheSMattheILC.Wepresenttheleading order (LO) and next-to-leading order (NLO) EW corrected cross sections. Ournumerical results show that the one-loop electroweak corrections obviously suppressthe tree-level cross section.Higgs boson in association with gauge boson production processes become morepromisingchannelsforHiggssearchingbyusingthetechniquesofjetreconstruction, b-tagging and lepton identification, which are necessary to be studied carefully. Since thetheoreticalpredictionsattheLOcontaintheoreticaluncertainties,itisnecessarytostudythe NLO and next-to-next-to-leading order (NNLO) QCD corrections of the processes.Theoretically, the NLO QCD correction to the V H~0+jet (V=W~±, Z~0) production process is an important part of the V H~0production process at the NNLO QCD. In thisthesis westudytheNLOQCDcorrectionstotheprocesspp/ppˉ→W~±H~0+jet atthehadron colliders and the process pp→Z~0H~0+jet at the LHC, respectively. The cor-responding NLO QCD corrected cross sections and kinematic observable distributionsare presented. Our numerical results show that the NLO QCD corrections obviouslyreduce the theoretical uncertainty caused by factorization and renormalization scales.In this thesis,we made the following innovations:In this thesis we calculate and study the complete one-loop electroweak cor-rections to the production of three Z0-boson in the the framework of the SM atthe ILC for the fist time, and provide precise theoretical predictions. Our resultsas theoretical reference for experimental analysis are helpful for further probingof gauge-boson coupling and finding new physics. Following our calculations,French theorists(Fawzi Boudjema, Le Duc Ninh Ninh, et al.) have recalculatedthis process independently and confirmed the correctness of our results.The scale uncertainty induced by the factorization and renormalization scales isone of the main sources of the theoretical uncertainty. In order to reduce thetheoretical uncertainty, it is necessary to evaluate the NNLO QCD correction-s for some important processes. The study of V H~0+jet production at QCDNLO provides an important way to evaluate the main NNLO QCD correctionsof the V H0production process. In this thesis, we calculate NLO QCD correc-tions to the process pp/ppˉ→W~±H~0+jet at hadron colliders and the processpp→Z~0H~0+jet at the LHC in the framework of the SM for the first timeand also study the impacts of different jet event selection schemes on the NLOQCD corrected cross section, respectively. We present the most precise theoret-ical predictions for the processes so far. The NLO QCD radiative correction tothe process pp/ppˉ→W~±H~0+jet/pp→Z~0H~0+jet is an important part ofthe NNLO QCD correction to the process pp/ppˉ→W~±H~0/pp→Z~0H~0. Ournumerical results show that the NLO QCD radiative corrections obviously reducethe theoretical uncertain caused by factorization/renormalization scale, which arehelpful for the experimental discovery of Higgs boson and the study of the cou-plings between Higgs and gauge bosons as theoretical reference.