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Auger M, Auty DJ, Barbeau PS, Beauchamp E, Belov V, Benitez-Medina C, Breidenbach M, Brunner T, Burenkov A, Cleveland B, Cook S, Daniels T, Danilov M, Davis CG, Delaquis S, deVoe R, Dobi A, Dolinski MJ, Dolgolenko A, Dunford M, Fairbank W, Farine J, Feldmeier W, Fierlinger P, Franco D, Giroux G, Gornea R, Graham K, Gratta G, Hall C, Hall K, Hargrove C, Herrin S, Hughes M, Johnson A, Johnson TN, Karelin A, Kaufman LJ, Kuchenkov A, Kumar KS, Leonard DS, Leonard F, Mackay D, MacLellan R, Marino M, Mong B, Montero Díez M, Müller AR, Neilson R, Nelson R, Odian A, Ostrovskiy I, O'Sullivan K, Ouellet C, Piepke A, Pocar A, Prescott CY, Pushkin K, Rowson PC, Russell JJ, Sabourov A, Sinclair D, Slutsky S, Stekhanov V, Tolba T, Tosi D, Twelker K, Vogel P, Vuilleumier JL, Waite A, Walton T, Weber M, Wichoski U, Wodin J, Wright JD, Yang L, Yen YR, Zeldovich OY. Search for neutrinoless double-beta decay in 136Xe with EXO-200. Phys Rev Lett 2012; 109:032505. [PMID: 22861843 DOI: 10.1103/physrevlett.109.032505] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Indexed: 06/01/2023]
Abstract
We report on a search for neutrinoless double-beta decay of 136Xe with EXO-200. No signal is observed for an exposure of 32.5 kg yr, with a background of ∼1.5×10(-3) kg(-1) yr(-1) keV(-1) in the ±1σ region of interest. This sets a lower limit on the half-life of the neutrinoless double-beta decay T(1/2)(0νββ)(136Xe)>1.6×10(25) yr (90% C.L.), corresponding to effective Majorana masses of less than 140-380 meV, depending on the matrix element calculation.
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Affiliation(s)
- M Auger
- LHEP, Albert Einstein Center, University of Bern, Bern, Switzerland
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Ackerman N, Aharmim B, Auger M, Auty DJ, Barbeau PS, Barry K, Bartoszek L, Beauchamp E, Belov V, Benitez-Medina C, Breidenbach M, Burenkov A, Cleveland B, Conley R, Conti E, Cook J, Cook S, Coppens A, Counts I, Craddock W, Daniels T, Danilov MV, Davis CG, Davis J, deVoe R, Djurcic Z, Dobi A, Dolgolenko AG, Dolinski MJ, Donato K, Dunford M, Fairbank W, Farine J, Fierlinger P, Franco D, Freytag D, Giroux G, Gornea R, Graham K, Gratta G, Green MP, Hägemann C, Hall C, Hall K, Haller G, Hargrove C, Herbst R, Herrin S, Hodgson J, Hughes M, Johnson A, Karelin A, Kaufman LJ, Koffas T, Kuchenkov A, Kumar A, Kumar KS, Leonard DS, Leonard F, LePort F, Mackay D, MacLellan R, Marino M, Martin Y, Mong B, Díez MM, Morgan P, Müller AR, Neilson R, Nelson R, Odian A, O'Sullivan K, Ouellet C, Piepke A, Pocar A, Prescott CY, Pushkin K, Rivas A, Rollin E, Rowson PC, Russell JJ, Sabourov A, Sinclair D, Skarpaas K, Slutsky S, Stekhanov V, Strickland V, Swift M, Tosi D, Twelker K, Vogel P, Vuilleumier JL, Vuilleumier JM, Waite A, Waldman S, Walton T, Wamba K, Weber M, Wichoski U, Wodin J, Wright JD, Yang L, Yen YR, Zeldovich OY. Observation of two-neutrino double-beta decay in 136Xe with the EXO-200 detector. Phys Rev Lett 2011; 107:212501. [PMID: 22181874 DOI: 10.1103/physrevlett.107.212501] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2011] [Indexed: 05/31/2023]
Abstract
We report the observation of two-neutrino double-beta decay in (136)Xe with T(1/2) = 2.11 ± 0.04(stat) ± 0.21(syst) × 10(21) yr. This second-order process, predicted by the standard model, has been observed for several nuclei but not for (136)Xe. The observed decay rate provides new input to matrix element calculations and to the search for the more interesting neutrinoless double-beta decay, the most sensitive probe for the existence of Majorana particles and the measurement of the neutrino mass scale.
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Affiliation(s)
- N Ackerman
- SLAC National Accelerator Laboratory, Stanford, California, USA
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Abstract
The alleviation of the acetylene blockage of nitrous oxide reduction by sulfide was studied in anaerobically incubated Brookston soil to better characterize the process. Removal of nitrate-derived nitrous oxide from soil amended with acetylene and sulfide occurred earlier in the presence of glucose than it did in its absence. This was attributed to the influence of glucose on nitrous oxide production rather than reduction during the early stages of the soil incubation. Glucose was found to have no effect on reduction of injected nitrous oxide in the presence of acetylene- and sulfide-amended soil, whereas carbon dioxide significantly stimulated reduction. It is suggested that the microorganism(s) involved may use carbon dioxide as a cellular carbon source. The sulfide added to the soil probably did not act solely as an electron donor, as the number of electrons required to reduce the added nitrous oxide in our systems was greater than the amount supplied by the sulfide. The soil pH at which the alleviation occurred was 6.7 and was not affected by the sulfide treatment.
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Affiliation(s)
- D G Evans
- Departments of Land Resource Science and Environmental Biology, Ontario Agricultural College, University of Guelph, Guelph, Ontario, Canada N1G 2W1
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