Neutrino Physics Related with Underground Experiments

点击翻译按钮获取中文摘要

The pricipal objective of this three-year research project is to perform detailed investigations on the following three thema : (1) How to test the Einstein equivalence principle using neutrinos. (2) Physics of neutrinos from galactic supernova. (3) Some theoretical idea for making Superkamiokande to neutral-current detector.During the process of performing the study, however, it was recognized that we have to take the anomalies implied by the solar and the atmospheric neutrino observations at their face value. There is also an impressive success of the cold and hot dark matter model of the structure formation in the universe. Then, there appeared the fourth thema, (4) Structure of lepton mixing theough studying the three-flavor analysis of neutrino oscillations, which we divorted our pricipal effort in the last year of our project. Brief summary of the outcome and the present status of these thema are as follows :(1) We have made substantial progress in this topics. We have proposed t … More hat by using long baseline neutrino oscillation experiments the test of the equivalence principle can be done to the accuracy of 10^<-14>. We also examined in detail the sensitivity of testing the equivalence principle which is attainable by using solar neutrinos, and obtained 1-2 orders of magnitude better result. Finally we discussed the possibility of drastically improving the sensitivity by using neutrinos from AGN.The improvement is dramatic, some 21 decimal and 12 decimal places for massless and massive neutrinos, respectively.(2) We are in the way of developing code by which we can do better computation of the cross sections on oxigen target in water.(3) We examined MgCl and LiCl as soluble materials which can produce detectable signals, but the question of background level remains to be unresolved.(4) Complehensive analyzes are performed utilizing the above three hints for neutrino masses which come from astrophysical and cosmological observations and under the constraints from accelerator and reactor data. They illuminate that the pattern of lepton mixing is essentially determined up to the degeneracy which can then be resoled by imposing the neutrinoless double beta decay constraint. Less