Some Related Studies On Quark-lepton Favor Physics And Dark Matter Phenomenology

Particle physics is a frontier branch of physics which studies the nature ofthe elementary particles and the interactions between them. Two importantaspects of particle physics studies are: one is precision test of standard modelincluding fnding new methods to do it, and the other is to explore new physicsbeyond standard model. With the discovery of Higgs particle, the mechanism ofparticle mass generation and symmetry broken in the standard model has beentested. The standard model is very successful. However, the standard modelitself also has some problems, such as, lacking of physical explanations for thequark mixing, the origin of neutrino mass, the existence of dark matter and soon. Therefore, we studied some related topics of quark-lepton mixing, neutrinomasses and dark matter phenomena in this thesis.In the frst chapter, we briefy outlined the basics of standard model andsome aspects of new physics beyond. The theoretical and experimental statuson quark-lepton mixing and dark matter phenomena are briefy discussed. Inthe second chapter, we studied the parametrization of quark and lepton mixing.A new method of parametrization of quark mixing matrix has been developed.We proposed to use experimentally measurable CP violating quantities, α, β orγ in the unitarity triangle as the phase in Cabibbo-Kobayashi-Maskawa (CKM)matrix, and constructed explicit α, β and γ parameterizations. ApproximateWolfenstein-like expressions are also suggested. β is the most accurately mea-sured among these three phase angles, we therefore considered the β parametriza-tion the best one to use. We also proposed reparametrization invariant expres-sions for the complementarity relations in terms of the magnitude of the elementsin the quark and lepton mixing matrices. In the third chapter, we carried outthe SU(3) and U-spin symmetry analysis for CP violations and branching ratios in B+decays into π+π+π, π+K+K,K+π+πand K+K+Kmesons. We con-structed the amplitudes of the symmetry-invariant, symmetry-breaking and themomentum dependent terms in a systematic way and explained the experimentaldata on the branching ratios and CP asymmetries. We found that large sym-metry breaking efects are needed to explain the data by the numerical analysis.At last, in the fourth chapter we studied the mechanism of neutrino mass gen-eration, dark matter candidate and the relation between them. We constructedradiative inverse seesaw dark matter models and studied some phenomenologicalimplications of the model. In this model because neutrino masses are generatedat two loop level with inverse seesaw, the new physics scale can be as low as afew hundred GeV and the model also naturally contain dark matter candidate.The large Yukawa couplings linking the SM leptons and new particles, naturallyleading to the lepton favor violating efects. We fnd that future experimentaldata on μ→eγ and μ e conversion can further constrain the Yukawa cou-pling constant and test the model. The new charged scalar particles can afectsignifcantly the h→γγ branching ratio in the SM which is able to explain thedeviation between the SM prediction and the LHC data. We also studied someLHC signatures of the new particles in the model.