Studying The Origin Of Neutrino Masses, Lepton Flavor Mixings And Related Topics

Neutrinos play an essential role in particle physics, astronomy and cosmology. In this thesis, we first summarize the current theoretical and experimental status of neu-trino physics, and emphasize that neutrino oscillation has proved that neutrinos have non-degenerate masses and lepton flavors do mix. We know that there are also flavor mixings in quark sector. According to our experiences during the development of high energy physics, physics world is highly unified and symmetric. Hence, we believe that there might be some intrinsic correlation between quarks and leptons, e.g., quark lepton complementarity. Searching for the correlation between quarks and leptons is impor-tant in understanding the Standard Model and physics beyond the Standard Model. We discuss the parametrization dependence as well as the renormalization group running stability of quark lepton complementarity. Recently, the precise measurement of neu-trino flavor mixing parameters provoke the new exploration on neutrino mixing pattern. We rescrutinize the triminimal expansion based on bimaximal and tribimaximal mix-ing pattern. In addition, to understand the tiny mass of neutrino, seesaw mechanism is introduced. Seesaw mechanism includes type â…  seesaw mechanism, which is real-ized by introducing heavy Majorana neutrinos, type â…¡ seesaw mechanism, realized by introducing heavy scalar triplets and type â…¢ seesaw mechanism, realized by intro-ducing fermion triplets. Further, we introduce Majorana particles and Scalar triplets at the same time and discuss the lepton-number-violating signatures induced by the heavy Majorana neutrinos which could be discovered at the CERN Large Hadron Collider.