Neutrinos from CNO cycle at the present epoch of the solar neutrino research

The importance of the study of solar neutrinos generated in CNO cycle is discussed in view of the presently obtained data. The emphasis is given to the precise detemination of the flux of low energy pp-neutrinos as a main topic of future experimental program.Comment: 4 pages, 2 Figures, Contribution for Proceedings of the Erice School 2009 in "Progress in Particle and Nuclear Physics

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

The present data of gallium experiments provide indirectly the only experimental limit on the fraction of $\nu_2$ mass eigenstate for the $^8$B neutrinos from the Sun. However, if to use the experimental data alone, the fraction of $\nu_2$ and, consequently, $sin^2\theta_{sol}$ still is allowed to be varied within a rather broad range. The further experimental efforts are needed to clear this point.Comment: 13 pages, 1 figure, 1 table. Corrected version, published in JCAP04(2007)00

On a Search for Hidden Photon CDM by a Multi-Cathode Counter

We report on a new technique of a Multi-Cathode Counter (MCC) developed to search for hidden photon (HP) cold dark matter (CDM) with a mass from 5 to 500 eV. The method is suggested in the assumption that HP-photon mixing causes emission of single electrons from a metal cathode if the mass of hidden photon is greater than a work function of the metal. The measured effect from HP should be dependent on work function of the metal and on the structure of electronic shells of the metal used as a cathode. Potentially this can be used for a verification of the results obtained. Some preliminary results for the upper limit for mixing parameter X have been obtained for HP with a mass from 5 eV to 10 keV as a pure illustration of the potential of this technique. The efforts are continued to refine the procedure of data treatment and to improve the work of MCC. A new detector with a more developed design is under construction.Comment: 13 pages, 9 figures; v.2: minor changes/corrections made, following referee's recommendations; accepted for publication in "Advances in High Energy Physics", open special issue. arXiv admin note: text overlap with arXiv:1512.0467