Some Unsettled Questions in the Problem of Neutrino Oscillations
  It is noted that the theory of neutrino oscillations can be constructed only in the framework of the particle physics theory, where is a mass shell conception and then transitions (oscillations) between neutrinos with equal masses are real and between neutrinos with different masses are virtual. It is necessary to solve the question: which type of neutrino transitions (oscillations) is realized in nature? There can be three types of neutrino transitions (oscillations). At present it is considered that Dirac and Majorana neutrino oscillations can be realized. It is shown that we cannot put Majorana neutrinos in the standard weak interactions theory without violation of the gauge invariance. Then it is obvious that there can be only realized transitions (oscillations) between Dirac neutrinos with different flowers. Also it is shown that the mechanism of resonance enhancement of neutrino oscillations in matter cannot be realized without violation of the law of energy-momentum conservation. Though it is supposed that we see neutrino oscillations in experiments, indeed there only transitions between neutrinos are registered. In order to register neutrino oscillations it is necessary to see second or even higher neutrino oscillation modes in experiments. For this purpose we can use the elliptic character of the Earth orbit. The analysis shows that the SNO experimental results do not confirm smallest of nu_e to nu_\tau transition angle mixings, which was obtained in CHOOZ experiment. It is also noted that there is contradiction between SNO, Super-Kamiokande, Homestake and the SAGE and GNO (GALLEX) data. 
Kh. M. Beshtoev