Precise Electroweak Measurement And Low-energy Phenomenological Theory In Supersymmetry

The standard model is a very successful model. It has been accepted in the field ofhigh-energy physics. As an important development of experimental physics, CERN hasconfirmed the existence of Higgs particle with high confidence level in March2013. Inspite of this, it can not provide the dark matter candidate, and can not guarantee thefinite mass of Higgs particle which is involved in the spontaneous symmetry brokenmechanism. The physical community generally believes in the existence of new physics,especially supersymmetry can solve lots of legacy issues in Standard Model. Withvarious considerations, people generally believe that the characteristic scale of the newphysics surround the TeV, and the Large Hadron Collider (LHC) offer a quite wellexperimental platform for the test of new physics, such as supersymmetry.As one of the major new physics models, supersymetry not only could solve theimportant problems in the standard model, but also give the most powerful explanation toGrand Unified Theory. The experimental data from LHC7and LHC8has dischargedlighter supersymmetric particles, and have found the125GeV SM-like Higgs bosonsince last two years. The latest experimental data of them given strong limits to thesupersymmetry parameters.This thesis presented an analytic calculation for the relevant parameters S,T,U ofthe precise electroweak measurement in the MSSM and NMSSM. Combined with latestexperimental data, we gave the restraints of the parameters in supersymmetry. Then wehave analysis the physical meaning of the parameter space which satisfied variousrestricted condition from the point of precise electroweak measurement, and found that:1、The minimum supersymmetry standard model in the region tan50areexcluded at99%CL.2、The next to minimum supersymmetry standard model is relatively moreconsistent with electroweak experiments.With the running of the LHC, the data size increased and the accuracy ofexperiments continuously improved, the applications of precision electroweak analysiswill be more effective in supersymmetry.The last section discussed the constructing of a class of supersymmetric models.We proposed a simple model of the gauge mediation. It can explain the problem of themass of light gaugino and Bproblems in supersymmetry simultaneously.