(?)→X_sγ Restrictions On Parameter Space Of Supersymmetric Model

The primary mission for particle physics is to verify the accuracy of the standard model and to search for new physics beyond the standard model at present.The rare B meson decay process can give rigorous constraints condition to the new physics beyond the standard model.In this thesis,we study the decay branch ratio（?）→X_sγ in the supersymmetric model where the baryon number and lepton number are local gauge symmetries（BLMSSM）.It is a significant process to detect new physics beyond the standard model.Through theoretical analysis mainly,draw all the one-loop Feynman diagrams.Based on Feynman rules in this model,we write down the amplitude of each one-loop Feynman diagram.And then through the theoretical calculation,find out the effective Wilson coefficient of each graph,put them into the decay branch ratio formula,get the analytical results.On this basis,write program further,scan free parameters of the model,and find the sensitive parameters of branch ratio.And restrict the parameter space using the experiment and theory data.On numerical analysis,analyze the effects of coupling parametersλ₁ and λ₃ on the decay branch ratio results.As well as we analyze whether the coupling parameter Zm is of sensitivity under the specific parameter valueλ₁ andλ₃.By scanning the parameter space,we find that the result of decay branch is very sensitive toλ₁ andλ₃,with the increase of coupling parameters.After taking appropriate model parameters,The experimental value of the branch ratio give λ₁ andλ₃ a upper limit:λ₁/ 4p 0.09 and λ₃/ 4p 0.14.In this range,the new neutral standard boson added in super symmetry is m_Z＜1300GeV.