18 research outputs found

    New Limit for the Half-Life of 2K(2neutrino)-Capture Decay Mode of 78Kr

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    Features of data accumulated at 1817 hours in the experimental search for 2K(2 \nu)-capture decay mode of Kr-78 are discussed. The new limit for this decay half-life is found to be T_{1/2} > 2.3 *10^{20} yr. (90% C.L.).Comment: 7 pages, 4 figures, submitted to Phys. of Atom. Nuc

    Results of a search for 2β\beta-decay of 136^{136}Xe with high-pressure copper proportional counters in Baksan Neutrino Observatory

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    The experiment for the 2β\beta-decay of 136^{136}Xe search with two high-pressure copper proportional counters has been held in Baksan neutrino observatory. The search for the process is based on comparison of spectra measured with natural and enriched xenon. No evidence has been found for 2β\beta(2ν\nu)- and 2β\beta(0ν\nu)-decay. The decay half lifetime limit based on data measured during 8000 h is T1/2_{1/2}8.51021\geq8.5\cdot10^{21}yr for 2ν\nu-mode and T1/2_{1/2}3.11023\geq3.1\cdot10^{23}yr for 0ν\nu-mode (90%C.L.).Comment: 9 pages, 8 figures; talk at the NANP'05 Conference; submitted to Phys. At. Nuc

    Next stage of search for 2K(2ν\nu)-capture of 78^{78}Kr

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    A technique to search for 2K-capture of 78^{78}Kr with large low-background proportional counter filled with an enriched in 78^{78}Kr up to 99.8% sample of Krypton at a pressure of 4.51 is described in this paper. The results of first measurements are presented. Analysis of data collected during 159 hours yielded new limit to the half-life of 78^{78}Kr with regard to 2K-capture (T1/261021_{1/2}\geq6\cdot10^{21} yr (90% C.L.)). Sensitivity of the facility to the process for one year of measurement was evaluated to be S=1.01022\texttt{S}=1.0\cdot10^{22} yr (90% C.L.).Comment: 4 pages, 5 figures; talk at the NANP'05 Conference; submitted to Phys. At. Nuc

    Double beta decay: present status

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    The present status of double beta decay experiments (including the search for 2β+2\beta^{+}, ECβ+\beta^{+} and ECEC processes) are reviewed. The results of the most sensitive experiments are discussed. Average and recommended half-life values for two-neutrino double beta decay are presented. Conservative upper limits on effective Majorana neutrino mass and the coupling constant of the Majoron to the neutrino are established as <0.75 < 0.75 eV and <gee><1.9104<g_{ee} > < 1.9 \cdot 10^{-4}, respectively. Proposals for future double beta decay experiments with a sensitivity for the at the level of (0.01-0.1) eV are considered.Comment: 33 pages included 7 figures and 14 tables; an extended version of the invited talk at 13th Lomonosov Conference of Elementary Particle Physics, 23-29 August, 2007, Moscow, Russi