Neutrinoless Double Beta Decay And The Research Into New Physics Model

The paper is about the neutrinoless double beta decay in seesaw mechanism and the constraints on new physics model parameter.The detections of the solar neutrino and atmosphere neutrino provide a compelling evidence that neutrino is massive. Theoretical physicists also expand the Standard Model to generate the neutrino mass. Firstly, we introduce the relevant knowledge about the Standard Model and how the charged lepton, quark, and gauge bosons get their mass. The neutrino oscillation experiments show that there are mass differences between each generation of neutrino. Here we derive the oscillation probability when neutrino propagates in vacuum and matter.Seesaw mechanism is an effective way to generate the neutrino mass, while the majorana mass term will induce the ΔL=2lepton number violation processes, such as neutrinoless double beta decay, lepton number violation rare τ decay and rare meson decay,μ-e conversion in nuclei and so on.Meanwhile, the study of the neutrinoless double beta decay shed light on the origin of the neutrino, Dirac or Majorana and also help us determine the hierarchy of neutrino mass. The half time of the isotopes is proportional to the effective majorana mass. I update the data of the experiment and get the constraints to the neutrino mass.We make extensions of the Standard Model, such as adding sterile neutrinos, adding higgs triplets and left-right symmetry model. They will give new contributions to the Oυββ decay. Probing into them can give limits on the relevant new physics parameters effectively.