Constraints On The Neutrino Mass And Mass Hierarchy From Cosmological And Neutrino Experiments

In 1998 and 2001,Solar neutrino oscillation and Atmospheric neutrino oscillation were dis-covered separately at Super-Kamiokande detector experiments led by Kajita and Sudbury neutri-no observatory experiments led by McDonald.These discovery prove that neutrinos have non-zero stationary mass.Recently,oscillation experiments have been able to measure precisely two squared mass differences of neutrino masses,giving rise to two kinds of neutrino mass orders,i.e.the normal hierarchy?NH?m₁<m₂<m₃and the inverted hierarchy?IH?m₃<m₁<m₂.In particle physics,neutrinoless double beta decay experiments not only confirms the nature of neutrino,but also determines the mass order of the neutrino.In cosmology,the presence of neu-trinos mass influences the evolution of the universe on both background scale and perturbation scale.Hence,information of neutrino mass could be extracted from the cosmic microwave back-ground radiation and large scale structure observation data.According to experimental results of neutrino oscillation,neutrino mass are not less than 0.06eV when positive ordering and not less than 0.1eV in inverted orderings,if the constraint results is less than 0.1eV,reverse ordering will be ruled out.In this paper,we introduce into the standard of?CDM cosmological model an extra parameter?to represent the sequence of neutrino mass order.We use the Markov Chain Monte Carlo method,with the data of Planck 2015+BAO+SN+H₀plus the neutrino oscillation and neutrino double beta decay data to constrain the neutrino mass and neutrino mass hierarchy.In this paper,at first,we explained the research background,research content and chapter arrangement of the subject,and then introduced the basic background knowledge of cosmology.At the same time,we also showed the geometric observation of background evolution and the dynamic observation of structure growth of common used.Then we introduced the basic theory of neutrino cosmology,including the evolution of neutrinos in the universe,the cosmological effect of neutrinos.Next,we gave a brief introduction of the neutrino discovery process in particle physics,neutrino oscillation and neutrinoless double beta decay.Our main work was in chapter 4.In the fourth chapter,we first introduced the method of bayesian analysis.We mainly compared the limit results of neutrino mass and mass order under the condition of using two different sets of data,and discussed the influence of different priors on the neutrino mass order.The last part were the summary and prospect of this paper.