On the Mass Eigenstate Composition of the 8 B Neutrinos from the Sun.

The present data of gallium experiments provide indirectly the experimental limit on the fraction of ν 2 mass eigenstate for the 8 B neutrinos from the Sun. However, if to use the experimental data alone, the fraction of ν 2 and, consequently, sin 2 θ 12 still is allowed to be varied within a rather broad range. The further experimental efforts are needed to clear this point. Introduction. The study of solar neutrinos performed during more than 40 years in a number of experiments [1]–[7] have shown unambiguously that electron neu-trinos generated in the matter of the Sun are converted in other flavors on the way to the Earth. That was the resolution of a long-standing " solar neutrino problem ". The experiment KamLAND [8] has observed the oscillations of electron neutrinos responsible for the deficit of solar neutrinos, using antineutrinos from reactors. The global analyses of all data performed in a number of papers, (see, for example, [9] and references therein) determined the parameters of neutrino oscillations responsible for the deficit of solar neutrinos