Precision Study On Triple Gauge Boson Production At High Energy Colliders

The Standard Model of particle physics is the most successful theory ever. Af-ter the descovery of Higgs boson, the main goals of the forthcoming experiments are the precise verification of Standerd Model (SM) and to discover the signature of new physics beyond it. The measurement of the quartic gauge couplings (QGCs) of elec-troweak bosons is very important for the test of the gauge structure and electroweak symmetry breaking mechanism in SM. For the direct study of the QGCs, the measure-ments of the triple gauge boson (TGB) productons are required. Therefore in thesis I focus myself on the precise study of the TGB productions at high energy colliders both in and beyond the SM.As the ZZW production at Large Hadron Collider (LHC) is directly related to the ZZW+W-QGC, it is of particular interest and any deviation from the SM predictions would hint at the existence of new physics. Among the various extensions of the SM, the large extra dimensions (LED) model is an attractive one because it predicts possible quantum gravity effects at TeV scale, so we investigate the possible LED effect in-duced by the Kaluza-Klein (KK) gravitons up to the QCD next-to-leading order (NLO) on ZZW production at LHC. The numerical results demonstrate that the NLO QCD corrections are sizeable and reduce the leading oredr (LO) LED effect remarkably. We conclude that the LO result overestimates the LED effect and the NLO QCD corrections are necessary to provide a believable theoretical prediction in the LED model. We also find the NLO QCD corrections and the LED effect depend on the phase space strongly and the LED effect could be significant for ZZW production at the 14 TeV LHC by adopting proper event selection criteria. Particularly in the high pT, central rapidity y and large MZZ regions, the LED effect becomes to be evidently large.Due to the heavy background at hadron collider, the triple gauge boson produc-tions at the future International Linear Collider (ILC) are much cleaner than at hadron machines. Therefore, the precise theoretical understanding of these processed at the ILC at least to one-loop order is necessary. Since the W+W-γ production can be used to explore the W+W-γγ and W+W-Zγ QGCs, We provide and discuss the preci-sion predictions for the W+W-γ production at the ILC including the full EW one-loop corrections and high order initial state radiation (ISR) contributions in the SM. The de-pendence of the leading order (LO) and EW corrected cross sections on the colliding energy is investigated. We find that the EW correction suppresses the LO cross section significantly, and the ISR effect beyond O(α) is important near the threshold, but it is negligible in the higher energy region. We also provide the LO and EW corrected distributions of the transverse momenta and rapidity of final W--boson and photon as well as the invariant W+-pair mass at (?)=500GeV. From the various kinematic dis-tributions, we find that EW correction strongly depends on phase space. Finally, we investigate the leptonic decay of the final W-boson pair by adopting the narow width approximation, and we find that the final photons and leptons can be well separated from each other.In summary, the achievements of the thesis are listed as follows:● We studied the NLO QCD corrections to pp→ZZW*±+X process in the LED model for the first time. Our results show that the NLO QCD corrections are sig-nificant and reduce the LO LED effect obviously. We also find that the LED effect in ZZW production concentrates in the high pT, central rapidity and large MZZ regions and can be enhanced significantly after adopting proper event selection criteria, which is very helpful for detecting the LED effect on ZZW production in experiment.● We provided the most precise prediction of W+W*-γ production at the 1LC. We calculated the full EW one-loop corrections and high order initial state radiation (ISR) contributions in the SM. Our results show that the EW correction suppresses the LO cross section significantly, and the ISR effect beyond O(α) is important when (?) near the threshold, but it is negligible in the higher colliding energy region. We also studied the various kinematic distributions and the sequential leptonic decay of the final W-boson pair. Our study is useful for the measurment of W+W-γγ and W+W-Zγ QGCs through e+e-→W+W-γ process.● In the calculation of loop diagrams, we encounterd numerical instabilities result-ing from the small Gram determinant (detG) and scalar one-loop four point in-tegrals. To solve the problems, we developed the codes for the calculation of the scalar and tensor integrals based on the LoopTools package. The modified LoopTools can swith to the quadruple precision codes automatically when detG is small enough, by using it the numerical instability originating from the small detG can be solved effectively. We also fixed some bugs of the program library in LoopTools for the calculation of scalar integrals. Due to the universality of these problems, the modified LoopTools is widely used in our lab.● In the calculation of real emission parts, the traditional method in our research group is the two cutoff phase space slicing method which is not satisfactory be-cause of serious cancelation between large numbers in numerical calculations. In our work, we developed the codes of the dipole subtraction method to deal with the IR singularities in the real emission parts and the efficiency of numerical inte-gration was improved significantly. We also introduced a parameter α to decrease the size of dipole phase space. The "missed-binning" problem can be suppressed effectively by taking proper value of α.