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Sample records for 130te double beta

  1. Search for Neutrinoless Double-Beta Decay of $^{130}$Te with CUORE-0

    Alfonso, K; Avignone, F T; Azzolini, O; Balata, M; Banks, T I; Bari, G; Beeman, J W; Bellini, F; Bersani, A; Biassoni, M; Brofferio, C; Bucci, C; Caminata, A; Canonica, L; Cao, X G; Capelli, S; Cappelli, L; Carbone, L; Cardani, L; Casali, N; Cassina, L; Chiesa, D; Chott, N; Clemenza, M; Copello, S; Cosmelli, C; Cremonesi, O; Creswick, R J; Cushman, J S; Dafinei, I; Dally, A; Dell'Oro, S; Deninno, M M; DiDomizio, S; DiVacri, M L; Drobizhev, A; Ejzak, L; Fang, D Q; Faverzani, M; Fernandes, G; Ferri, E; Ferroni, F; Fiorini, E; Freedman, S J; Fujikawa, B K; Giachero, A; Gironi, L; Giuliani, A; Gorla, P; Gotti, C; Gutierrez, T D; Haller, E E; Han, K; Hansen, E; Heeger, K M; Hennings-Yeomans, R; Hickerson, K P; Huang, H Z; Kadel, R; Keppel, G; Kolomensky, Yu G; Lim, K E; Liu, X; Ma, Y G; Maino, M; Martinez, M; Maruyama, R H; Mei, Y; Moggi, N; Morganti, S; Nisi, S; Nones, C; Norman, E B; Nucciotti, A; O'Donnell, T; Orio, F; Orlandi, D; Ouellet, J L; Pagliarone, C E; Pallavicini, M; Palmieri, V; Pattavina, L; Pavan, M; Pedretti, M; Pessina, G; Pettinacci, V; Piperno, G; Pirro, S; Pozzi, S; Previtali, E; Rosenfeld, C; Rusconi, C; Sala, E; Sangiorgio, S; Santone, D; Scielzo, N D; Sisti, M; Smith, A R; Taffarello, L; Tenconi, M; Terranova, F; Tomei, C; Trentalange, S; Ventura, G; Vignati, M; Wagaarachchi, S L; Wang, B S; Wang, H W; Wielgus, L; Wilson, J; Winslow, L A; Wise, T; Zanotti, L; Zarra, C; Zhang, G Q; Zhu, B X; Zucchelli, S

    2015-01-01

    We report the results of a search for neutrinoless double-beta decay in a 9.8~kg$\\cdot$yr exposure of $^{130}$Te using a bolometric detector array, CUORE-0. The characteristic detector energy resolution and background level in the region of interest are $5.1\\pm 0.3{\\rm~keV}$ FWHM and $0.058 \\pm 0.004\\,(\\mathrm{stat.})\\pm 0.002\\,(\\mathrm{syst.})$~counts/(keV$\\cdot$kg$\\cdot$yr), respectively. The median 90%~C.L. lower-limit sensitivity of the experiment is $2.9\\times 10^{24}~{\\rm yr}$ and surpasses the sensitivity of previous searches. We find no evidence for neutrinoless double-beta decay of $^{130}$Te and place a Bayesian lower bound on the decay half-life, $T^{0\

  2. The Search for Neutrinoless Double Beta Decay with 130Te with CUORE-0

    This thesis describes the design, operation and results of an experimental search for neutrinoless double beta decay (0νββ) of 130Te using the CUORE-0 detector. The discovery of 0νββ would have profound implications for particle physics and our understanding of the Universe. Its discovery would demonstrate the violation of lepton number and imply that neutrinos are Majorana fermions and therefore their own anti-particles. Combined with other experimental results, the discovery of 0νββ could also have implications for understanding the absolute neutrino mass scale as well as the presently unknown neutrino mass hierarchy. The CUORE experiment is a ton-scale search for 0νββ in 130Te expected to begin operation in late 2015. The first stage of this experiment is a smaller 39-kg active-mass detector called CUORE-0. This detector contains 11 kg of 130Te and operates in the Laboratori Nazionali del Gran Sasso lab in Italy from 2013-2015. The results presented here are based on a natTeO2 exposure of 35.2 kg·yr, or 9.8 kg·yr exposure of 130Te collected between 2013-2015. We see no evidence of 0νββ and place an upper limit on the 0νββ decay rate of Γ0νββ<0.25x1024 yr1 (90 % C.L.), corresponding to a lower limit on the half-life of T1/20ν>2.8x1024 yr (90 % C.L.). We combine the present result with the results of previous searches in 130Te. Combining it with the 1.2 kg·Te exposure from the Three Towers Test run we place a half-life limit of T1/203ν>3.3x1024 yr (90 % C.L.). And combining these results with the 19.75 kg·yr 130Te exposure from Cuoricino, we place the strongest limit on the 0νββ half-life of 130Te to date, at T1/20ν>4.5x1024 yr (90 % C.L.). Using the present nuclear matrix element calculations for 130Te, this result corresponds to a 90 % upper limit range on the effective Majorana mass of mββ<250-710 meV.

  3. Searching for neutrinoless double-beta decay of {sup 130}Te with CUORE

    CUORE,; Artusa, D. R.; Avignone III, F. T.; Azzolini, O.; Balata, M.; Banks, T. I.; Bari, G.; Beeman, J.; Bellini, F.; Bersani, A.; Biassoni, M.; Brofferio, C.; Bucci, C.; Cai, X. Z.; Camacho, A.; Canonica, L.; Cao, X. G.; Capelli, S.; Carbone, L.; Cardani, L.; Carrettoni, M.; Casali, N.; Chiesa, D.; Chott, N.; Clemenza, M.; Copello, S.; Cosmelli, C.; Cremonesi, O.; Creswick, R. J.; Dafinei, I.; Dally, A.; Datskov, V.; Biasi, A. De; Deninno, M. M.; Domizio, S. Di; Vacri, M. L. di; Ejzak, L.; Fang, D. Q.; Farach, H. A.; Faverzani, M.; Fernandes, G.; Ferri, E.; Ferroni, F.; Fiorini, E.; Franceschi, M. A.; Freedman, S. J.; Fujikawa, B. K.; Giachero, A.; Gironi, L.; Giuliani, A.; Goett, J.; Gorla, P.; Gotti, C.; Gutierrez, T. D.; Haller, E. E.; Han, K.; Heeger, K. M.; Hennings-Yeomans, R.; Huang, H. Z.; Kadel, R.; Kazkaz, K.; Keppel, G.; Kolomensky, Yu. G.; Li, Y. L.; Ligi, C.; Liu, X.; Ma, Y. G.; Maiano, C.; Maino, M.; Martinez, M.; Maruyama, R. H.; Mei, Y.; Moggi, N.; Morganti, S.; Napolitano, T.; Nisi, S.; Nones, C.; Norman, E. B.; Nucciotti, A.; O' Donnell, T.; Orio, F.; Orlandi, D.; Ouellet, J. L.; Pallavicini, M.; Palmieri, V.; Pattavina, L.; Pavan, M.; Pedretti, M.; Pessina, G.; Pettinacci, V.; Piperno, G.; Pira, C.; Pirro, S.; Previtali, E.; Rampazzo, V.; Rosenfeld, C.; Rusconi, C.; Sala, E.; Sangiorgio, S.; Scielzo, N. D.; Sisti, M.; Smith, A. R.; Taffarello, L.; Tenconi, M.; Terranova, F.; Tian, W. D.; Tomei, C.; Trentalange, S.; Ventura, G.; Vignati, M.; Wang, B. S.; Wang, H. W.; Wielgus, L.; Wilson, J.; Winslow, L. A.; Wise, T.; Woodcraft, A.; Zanotti, L.; Zarra, C.; Zhu, B. X.; Zucchelli, S.

    2014-02-24

    Neutrinoless double-beta (0{nu}{beta}{beta}) decay is a hypothesized lepton-number-violating process that offers the only known means of asserting the possible Majorana nature of neutrino mass. The Cryogenic Underground Observatory for Rare Events (CUORE) is an upcoming experiment designed to search for 0{nu}{beta}{beta} decay of {sup 130}Te using an array of 988 TeO{sub 2} crystal bolometers operated at 10 mK. The detector will contain 206 kg of {sup 130}Te and have an average energy resolution of 5 keV; the projected 0{nu}{beta}{beta} decay half-life sensitivity after five years of live time is 1.6 x 10{sup 26} y at 1{sigma} (9.5x10{sup 25} y at the 90% confidence level), which corresponds to an upper limit on the effective Majorana mass in the range 40-100 meV (50-130 meV). In this paper we review the experimental techniques used in CUORE as well as its current status and anticipated physics reach.

  4. Neutrinoless double beta decay search for 130Te: cuoricino status and cuore prospects

    CUORE is a ∼ I-ton experiment to search for Neutrinoless Double Beta Decay of 130Te using 988 TeO2 bolometers. It aims at reaching a sensitivity of the order of few tens of MeV on the effective neutrino mass. CUORICINO, a single CUORE tower running since 2003 in the Gran Sasso Underground Laboratory (LNGS), plays an important role as a standing alone experiment and for developing the future CUORE setup. Present results already achieved and studies that are underway are presented and discussed

  5. Searching for Neutrinoless Double-Beta Decay of 130Te with CUORE

    D. R. Artusa

    2015-01-01

    Full Text Available Neutrinoless double-beta (0νββ decay is a hypothesized lepton-number-violating process that offers the only known means of asserting the possible Majorana nature of neutrino mass. The Cryogenic Underground Observatory for Rare Events (CUORE is an upcoming experiment designed to search for 0νββ decay of 130Te using an array of 988 TeO2 crystal bolometers operated at 10 mK. The detector will contain 206 kg of 130Te and have an average energy resolution of 5 keV; the projected 0νββ decay half-life sensitivity after five years of livetime is 1.6 × 1026 y at 1σ (9.5 × 1025 y at the 90% confidence level, which corresponds to an upper limit on the effective Majorana mass in the range 40–100 meV (50–130 meV. In this paper, we review the experimental techniques used in CUORE as well as its current status and anticipated physics reach.

  6. Measurement of the Two-Neutrino Double Beta Decay Half-life of $^{130}$Te with the CUORE-0 Experiment

    Alduino, C; Artusa, D R; Avignone, F T; Azzolini, O; Banks, T I; Bari, G; Beeman, J W; Bellini, F; Bersani, A; Biassoni, M; Branca, A; Brofferio, C; Bucci, C; Camacho, A; Caminata, A; Canonica, L; Cao, X G; Capelli, S; Cappelli, L; Carbone, L; Cardani, L; Carniti, P; Casali, N; Cassina, L; Chiesa, D; Chott, N; Clemenza, M; Copello, S; Cosmelli, C; Cremonesi, O; Creswick, R J; Cushman, J S; D'Addabbo, A; Dafinei, I; Davis, C J; Dell'Oro, S; Deninno, M M; Di Domizio, S; Di Vacri, M L; Drobizhev, A; Fang, D Q; Faverzani, M; Fernandes, G; Ferri, E; Ferroni, F; Fiorini, E; Franceschi, M A; Freedman, S J; Fujikawa, B K; Giachero, A; Gironi, L; Giuliani, A; Gladstone, L; Gorla, P; Gotti, C; Gutierrez, T D; Haller, E E; Han, K; Hansen, E; Heeger, K M; Hennings-Yeomans, R; Hickerson, K P; Huang, H Z; Kadel, R; Keppel, G; Kolomensky, Yu G; Leder, A; Ligi, C; Lim, K E; Liu, X; Ma, Y G; Maino, M; Marini, L; Martinez, M; Maruyama, R H; Mei, Y; Moggi, N; Morganti, S; Mosteiro, P J; Napolitano, T; Nones, C; Norman, E B; Nucciotti, A; O'Donnell, T; Orio, F; Ouellet, J L; Pagliarone, C E; Pallavicini, M; Palmieri, V; Pattavina, L; Pavan, M; Pessina, G; Pettinacci, V; Piperno, G; Pira, C; Pirro, S; Pozzi, S; Previtali, E; Rosenfeld, C; Rusconi, C; Sangiorgio, S; Santone, D; Scielzo, N D; Singh, V; Sisti, M; Smith, A R; Taffarello, L; Tenconi, M; Terranova, F; Tomei, C; Trentalange, S; Vignati, M; Wagaarachchi, S L; Wang, B S; Wang, H W; Wilson, J; Winslow, L A; Wise, T; Woodcraft, A; Zanotti, L; Zhang, G Q; Zhu, B X; Zimmermann, S; Zucchelli, S

    2016-01-01

    We report on the measurement of the two-neutrino double beta decay half-life of $^{130}$Te with the CUORE-0 detector. From an exposure of 33.4 kg$\\cdot$y of TeO$_2$, the half-life is determined to be $T_{1/2}^{2\

  7. Measurement of the Double Beta Decay Half-life of 130Te with the NEMO-3 Detector

    Arnold, R; Baker, J; Barabash, A S; Basharina-Freshville, A; Blondel, S; Bongrand, M; Broudin-Bay, G; Brudanin, V; Caffrey, A J; Chapon, A; Chauveau, E; Durand, D; Egorov, V; Flack, R; Garrido, X; Grozier, J; Guillon, B; Hubert, Ph; Jackson, C M; Jullian, S; Kauer, M; Klimenko, A; Kochetov, O; Konovalov, S I; Kovalenko, V; Lalanne, D; Lamhamdi, T; Lang, K; Liptak, Z; Lutter, G; Mamedov, F; Marquet, Ch; Martin-Albo, J; Mauger, F; Mott, J; Nachab, A; Nemchenok, I; Nguyen, C H; Nova, F; Novella, P; Ohsumi, H; Pahlka, R B; Perrot, F; Piquemal, F; Reyss, J L; Richards, B; Ricol, J S; Saakyan, R; Sarazin, X; Shitov, Yu; Simard, L; Šimkovic, F; Smolnikov, A; Söldner-Rembold, S; Štekl, I; Suhonen, J; Sutton, C S; Szklarz, G; Thomas, J; Timkin, V; Torre, S; Tretyak, V I; Umatov, V; Vála, L; Vanyushin, I; Vasiliev, V; Vorobel, V; Vylov, T; Zukauskas, A

    2011-01-01

    This Letter reports results from the NEMO-3 experiment based on an exposure of 1275 days with 661g of 130Te in the form of enriched and natural tellurium foils. With this data set the double beta decay rate of 130Te is found to be non-zero with a significance of 7.7 standard deviations and the half-life is measured to be T1/2 = (7.0 +/- 0.9(stat) +/- 1.1(syst)) x 10^{20} yr. This represents the most precise measurement of this half-life yet published and the first real-time observation of this decay.

  8. Measurement of the Double Beta Decay Half-life of 130Te with the NEMO-3 Detector

    Arnold, R.; Augier, C.; Baker, J.; Barabash, A. S.; Basharina-Freshville, A.; Blondel, S.; Bongrand, M.; Broudin-Bay, G.; Brudanin, V.(Joint Institute for Nuclear Research, Dubna, Russia); Caffrey, A. J.; Chapon, A.; Chauveau, E.; Durand, D.; Egorov, V.; Flack, R.

    2011-01-01

    This Letter reports results from the NEMO-3 experiment based on an exposure of 1275 days with 661g of 130Te in the form of enriched and natural tellurium foils. The double beta decay rate of 130Te is found to be greater than zero with a significance of 7.7 standard deviations and the half-life is measured to be T1/2 = (7.0 +/- 0.9(stat) +/- 1.1(syst)) x 10^{20} yr. This represents the most precise measurement of this half-life yet published and the first real-time observation of this decay.

  9. Change of nuclear configurations in the neutrinoless double-$\\beta$ decay of $^{130}$Te $\\rightarrow$ $^{130}$Xe and $^{136}$Xe $\\rightarrow$ $^{136}$Ba

    Entwisle, J P; Tamii, A; Adachi, S; Aoi, N; Clark, J A; Freeman, S J; Fujita, H; Fujita, Y; Furuno, T; Hashimoto, T; Hoffman, C R; Ideguchi, E; Ito, T; Iwamoto, C; Kawabata, T; Liu, B; Miura, M; Ong, H J; Schiffer, J P; Sharp, D K; Süsoy, G; Suzuki, T; Szwec, S V; Takaki, M; Tsumura, M; Yamamoto, T

    2016-01-01

    The change in the configuration of valence protons between the initial and final states in the neutrinoless double-$\\beta$ decay of $^{130}$Te $\\rightarrow$ $^{130}$Xe and of $^{136}$Xe $\\rightarrow$ $^{136}$Ba has been determined by measuring the cross sections of the ($d$,$^3$He) reaction with 101-MeV deuterons. Together with our recent determination of the relevant neutron configurations involved in the process, a quantitative comparison with the latest shell-model and interacting-boson-model calculations reveals significant discrepancies. These are the same calculations used to determine the nuclear matrix elements governing the rate of neutrinoless double-$\\beta$ decay in these systems.

  10. Double-beta decay of $^{130}$Te to the first 0$^{+}$ excited state of $^{130}$Xe with CUORICINO

    Andreotti, E; Avignone, F T; Balata, M; Bandac, I; Barucci, M; Beeman, J W; Bellini, F; Brofferio, C; Bryant, A; Bucci, C; Canonica, L; Capelli, S; Carbone, L; Carrettoni, M; Clemenza, M; Cremonesi, O; Creswick, R J; Di Domizio, S; Dolinski, M J; Ejzak, L; Faccini, R; Farach, H A; Ferri, E; Fiorini, E; Foggetta, L; Giachero, A; Gironi, L; Giuliani, A; Gorla, P; Guardincerri, E; Gutierrez, T D; Haller, E E; Kazkaz, K; Kogler, L; Kraft, S; Maiano, C; Martinez, C; Martinez, M; Maruyama, R H; Newman, S; Nisi, S; Nones, C; Norman, E B; Nucciotti, A; Orio, F; Pallavicini, M; Palmieri, V; Pattavina, L; Pavan, M; Pedretti, M; Pessina, G; Pirro, S; Previtali, E; Risegari, L; Rosenfeld, C; Rusconi, C; Salvioni, C; Sangiorgio, S; Schaeffer, D; Scielzo, N D; Sisti, M; Smith, A R; Tomei, C; Ventura, G; Vignati, M

    2011-01-01

    The CUORICINO experiment was an array of 62 TeO$_{2}$ single-crystal bolometers with a total $^{130}$Te mass of $11.3\\,$kg. The experiment finished in 2008 after more than 3 years of active operating time. Searches for both $0\

  11. Shell model studies of competing mechanisms to the neutrinoless double-beta decay in $^{124}$Sn, $^{130}$Te, and $^{136}$Xe

    Neacsu, Andrei

    2016-01-01

    Neutrinoless double-beta decay is a predicted beyond Standard Model process that could clarify some of the not yet known neutrino properties, such as the mass scale, the mass hierarchy, and its nature as a Dirac or Majorana fermion. Should this transition be observed, there are still challenges in understanding the underlying contributing mechanisms. We perform a detailed shell model investigation of several beyond Standard Model mechanisms that consider the existence of right-handed currents. Our analysis presents different venues that can be used to identify the dominant mechanisms for nuclei of experimental interest in the mass A$\\sim$130 region ($^{124}$Sn, $^{130}$Te, and $^{136}$Xe). It requires an accurate knowledge of nine nuclear matrix elements that we calculate, in addition to the associated energy dependent phase-space factors.

  12. Measurement of 130Te double beta decay process in the NEMO-3 experiment- R and D of SuperNEMO project: study of the BiPo detector

    This thesis contains 2 parts: data analysis of the NEMO-3 experiment data and a study of a BiPo detector for the SuperNEMO project. NEMO-3 is searching for neutrinoless double beta decay process 2β0ν using direct detection of the 2 emitted electrons by a tracking detector coupled to a calorimeter. I completely studied the backgrounds in several analysis channels and gave the most accurate measurement of the allowed process with neutrinos emission for 130Te: T2ν(1/2) equals (6.1 ± 1.2 (stat) ± 0.6 (syst)) 1020 years. This result allows a good knowledge of the ultimate 2β2ν background for 2β0ν process research and helps to constrain or check the theoretical calculations of nuclear matrix elements, which have to be known with a good precision to determine the neutrino effective mass in case of 2β0ν observation. From NEMO-3 data, I also gave a limit on this effective neutrino massββ 130Te: T0ν(1/2) > 6.3 1022 years. Due to the low mass of 130Te contained in NEMO-3 (454 g), this result is not competitive with the limit recently published by CUORICINO for this isotope: T0ν(1/2) > 3.0 1024 years and mββ 0ν(1/2) > 1026 years, using the NEMO-3 detection principle but improving efficiency, radio-purity, energy resolution and reducing backgrounds. This background will be then limited by natural radioactive contaminations inside the source foils. Thus the SuperNEMO specifications concerning the source foil radio-purity are very high: A(208Tl) 214Bi) 208Tl and 214Bi contaminations, using identification of the Bi → Po chains. Foil source to measure is put between two scintillator planes allowing energy and time measurements. I studied BiPo-1 prototype, showed its technical feasibility, validated the principle and determined the sensitivity of the source measurement compared to backgrounds. Data analysis of BiPo-1 showed the possibility to measure 5 μBq/kg of 208Tl with the final BiPo. This result is not so far from SuperNEMO requirements and already shows a

  13. Large-Scale Calculations of the Double-Beta Decay of 76Ge, 130Te, 136Xe, and 150Nd in the Deformed Self-Consistent Skyrme Quasiparticle Random-Phase Approximation

    Mustonen, M T

    2013-01-01

    We use the axially-deformed Skyrme Quasiparticle Random-Phase Approximation (QRPA) together with the SkM* energy-density functional, both as originally presented and with the time-odd part adjusted to reproduce the Gamow-Teller resonance energy in 208Pb, to calculate the matrix elements governing the neutrinoless double-beta decay of 76Ge, 130Te, 136Xe, and 150Nd. Our matrix elements in 130Te and 136Xe are significantly smaller than those of previous QRPA calculations, primarily because of the difference in pairing or deformation between the initial and final nuclei. In 76Ge and 150Nd our results are similar to those of less computationally intensive QRPA calculations. We suspect the 76Ge result, however, because we are forced to use a spherical ground-state, even though the HFB indicates a deformed minimum.

  14. Double-β-decay Q values of 130Te, 128Te, and 120Te

    The double-β-decay Q values of 130Te, 128Te, and 120Te have been determined from parent-daughter mass differences measured with the Canadian Penning Trap mass spectrometer. The 132Xe-129Xe mass difference, which is precisely known, was also determined to confirm the accuracy of these results. The 130Te Q value was found to be 2527.01±0.32 keV, which is 3.3 keV lower than the 2003 Atomic Mass Evaluation recommended value and is consistent with another recent Penning trap measurement. The 128Te and 120Te Q values were found to be 865.87±1.31 and 1714.81±1.25 keV, respectively. For 120Te, this reduction in uncertainty of nearly a factor of 8 opens up the possibility of using this isotope for sensitive searches for neutrinoless double-electron capture and electron capture with β+emission.

  15. Analysis techniques for the evaluation of the neutrinoless double-β decay lifetime in 130Te with the CUORE-0 detector

    Alduino, C.; Alfonso, K.; Artusa, D. R.; Avignone, F. T.; Azzolini, O.; Banks, T. I.; Bari, G.; Beeman, J. W.; Bellini, F.; Bersani, A.; Biassoni, M.; Brofferio, C.; Bucci, C.; Caminata, A.; Canonica, L.; Cao, X. G.; Capelli, S.; Cappelli, L.; Carbone, L.; Cardani, L.; Carniti, P.; Casali, N.; Cassina, L.; Chiesa, D.; Chott, N.; Clemenza, M.; Copello, S.; Cosmelli, C.; Cremonesi, O.; Creswick, R. J.; Cushman, J. S.; Dafinei, I.; Dally, A.; Davis, C. J.; Dell'Oro, S.; Deninno, M. M.; di Domizio, S.; di Vacri, M. L.; Drobizhev, A.; Fang, D. Q.; Faverzani, M.; Fernandes, G.; Ferri, E.; Ferroni, F.; Fiorini, E.; Freedman, S. J.; Fujikawa, B. K.; Giachero, A.; Gironi, L.; Giuliani, A.; Gladstone, L.; Gorla, P.; Gotti, C.; Gutierrez, T. D.; Haller, E. E.; Han, K.; Hansen, E.; Heeger, K. M.; Hennings-Yeomans, R.; Hickerson, K. P.; Huang, H. Z.; Kadel, R.; Keppel, G.; Kolomensky, Yu. G.; Lim, K. E.; Liu, X.; Ma, Y. G.; Maino, M.; Marini, L.; Martinez, M.; Maruyama, R. H.; Mei, Y.; Moggi, N.; Morganti, S.; Mosteiro, P. J.; Nones, C.; Norman, E. B.; Nucciotti, A.; O'Donnell, T.; Orio, F.; Ouellet, J. L.; Pagliarone, C. E.; Pallavicini, M.; Palmieri, V.; Pattavina, L.; Pavan, M.; Pessina, G.; Pettinacci, V.; Piperno, G.; Pirro, S.; Pozzi, S.; Previtali, E.; Rosenfeld, C.; Rusconi, C.; Sala, E.; Sangiorgio, S.; Santone, D.; Scielzo, N. D.; Singh, V.; Sisti, M.; Smith, A. R.; Taffarello, L.; Tenconi, M.; Terranova, F.; Tomei, C.; Trentalange, S.; Ventura, G.; Vignati, M.; Wagaarachchi, S. L.; Wang, B. S.; Wang, H. W.; Wilson, J.; Winslow, L. A.; Wise, T.; Woodcraft, A.; Zanotti, L.; Zhang, G. Q.; Zhu, B. X.; Zimmermann, S.; Zucchelli, S.; Cuore Collaboration

    2016-04-01

    We describe in detail the methods used to obtain the lower bound on the lifetime of neutrinoless double-beta (0 ν β β ) decay in 130Te and the associated limit on the effective Majorana mass of the neutrino using the CUORE-0 detector. CUORE-0 is a bolometric detector array located at the Laboratori Nazionali del Gran Sasso that was designed to validate the background reduction techniques developed for CUORE, a next-generation experiment scheduled to come online in 2016. CUORE-0 is also a competitive 0 ν β β decay search in its own right and functions as a platform to further develop the analysis tools and procedures to be used in CUORE. These include data collection, event selection and processing, as well as an evaluation of signal efficiency. In particular, we describe the amplitude evaluation, thermal gain stabilization, energy calibration methods, and the analysis event selection used to create our final 0 ν β β search spectrum. We define our high level analysis procedures, with emphasis on the new insights gained and challenges encountered. We outline in detail our fitting methods near the hypothesized 0 ν β β decay peak and catalog the main sources of systematic uncertainty. Finally, we derive the 0 ν β β decay half-life limits previously reported for CUORE-0, T1/2 0 ν>2.7 ×1024yr , and in combination with the Cuoricino limit, T1/2 0 ν>4.0 ×1024yr .

  16. Neutrinoless double beta decay search with SNO+

    Lozza V.

    2014-01-01

    The SNO+ experiment is the follow up of SNO. The detector is located 2 km underground in the Vale Canada Ltd.’s Creighton Mine near Sudbury, Ontario, Canada. The active volume of the detector consists of 780 tonnes of Linear Alkyl Benzene (LAB) in an acrylic vessel of 12 m diameter, surrounded by about 9500 PMTs. The main goal of the SNO+ experiment is the search for neutrinoless double beta decay of 130Te. With an initial loading of 0.3% of natural tellurium (nearly 800 kg of 130Te), it is e...

  17. Change of nuclear configurations in the neutrinoless double-β decay of 130Te →130Be and 136Xe136Ba

    Entwisle, J. P.; Kay, B. P.; Tamii, A.; Adachi, S.; Aoi, N.; Clark, J. A.; Freeman, S. J.; Fujita, H.; Fujita, Y.; Furuno, T.; Hashimoto, T.; Hoffman, C. R.; Ideguchi, E.; Ito, T.; Iwamoto, C.; Kawabata, T.; Liu, B.; Miura, M.; Ong, H. J.; Schiffer, J. P.; Sharp, D. K.; Süsoy, G.; Suzuki, T.; Szwec, S. V.; Takaki, M.; Tsumura, M.; Yamamoto, T.

    2016-06-01

    The change in the configuration of valence protons between the initial and final states in the neutrinoless double-β decay of 130Te → 130Be and of 136Xe136Ba has been determined by measuring the cross sections of the (d ,3He) reaction with 101-MeV deuterons. Together with our recent determination of the relevant neutron configurations involved in the process, a quantitative comparison with the latest shell-model and interacting-boson-model calculations reveals significant discrepancies. These are the same calculations used to determine the nuclear matrix elements governing the rate of neutrinoless double-β decay in these systems.

  18. Thick-target yields of iodine isotopes from proton interactions in Te, and the double-β decays of 128,130Te

    We measured thick-target yields of 126,128,130I from bombardments of natural Te targets with 15-, 30-, 45-, and 50-MeV protons, together with iodine production cross sections for 1.85- and 5.0-GeV protons. Using these data, we have estimated the relative cosmic-ray induced production of 126Xe, 128Xe, and 130Xe in Te ores. These quantities are significantly different from those used previously in a determination of the ratio of the double-β decay half-lives of 130Te and 128Te, and as a result the cosmic-ray correction is smaller than previously assumed. A revised correction of cosmic-ray produced xenon can change the half-life ratio by about 6%. This quantity is of importance because it can be used to set a limit on the 0-ν double-β decay mode

  19. NEMO 3 double beta decay experiment: latest results

    Barabash, A S

    2008-01-01

    The double beta decay experiment NEMO~3 has been taking data since February 2003. The aim of this experiment is to search for neutrinoless decay and investigate two neutrino double beta decay in seven different enriched isotopes ($^{100}$Mo,$^{82}$Se, $^{48}$Ca, $^{96}$Zr, $^{116}$Cd, $^{130}$Te and $^{150}$Nd). After analysis of the data corresponding to 693 days, no evidence for $0\

  20. Double-beta decay in gauge theories

    The double-beta decay in gauge theories is considered. The review of the 76Ge, 82Se, 96Zr, 100Cd, 128Te, 130Te, 136Xe and 150Nd experimental nuclear targets is presented. The mechanism of the Majorana intermediate neutrino is considered. The R-parity of the violation of the contribution to the 0νββ decay is studied. The effective nucleon currents in dependence on the momentum are discussed. The extraction of the lepton number, violating the double-β decay parameters is presented

  1. Double beta decay of 128Te and RIS

    The paper considers the use of Resonance Ionization Spectroscopy (RIS) in the determination of the electron neutrino mass via the double beta decay of 128Te. An outline is given of the theoretical background to the electron neutrino restmass, and the importance of the neutrino properties in Grand Unification Theories. The detection method for double beta decay is described; the discussion is restricted to tellurium ores and the decays 128Te → 128Xe, and 130Te → 130Xe. A consideration of existing data on double beta decay of 128Te indicates that most aspects of the detection could benefit from RIS. (U.K.)

  2. Neutrinoless Double Beta Decay with CUORE-0: Physics Results and Detector Performance

    Canonica, L.

    2016-01-01

    The CUORE-0 experiment searches for neutrinoless double beta decay in ^{130} Te. It consists of an array of 52 tellurium dioxide crystals, operated as bolometers at a temperature of 10 mK, with a total mass of about 39 kg of TeO_2 . CUORE-0 has been built to test the performance of the upcoming CUORE experiment and represents the largest ^{130} Te bolometric setup currently in operation. This experiment has been running in the Gran Sasso National Laboratory, Italy, since March 2013. We report the results of a search for neutrinoless double beta decay in 9.8 kg years ^{130} Te exposure, which allowed us to set the most stringent limit to date on this half-life. The performance of the detector in terms of background rate and energy resolution are also reported.

  3. Neutrinoless double beta decay search with SNO+

    Lozza, V.

    2014-01-01

    The SNO+ experiment is the follow up of SNO. The detector is located 2 km underground in the Vale Canada Ltd.'s Creighton Mine near Sudbury, Ontario, Canada. The active volume of the detector consists of 780 tonnes of Linear Alkyl Benzene (LAB) in an acrylic vessel of 12 m diameter, surrounded by about 9500 PMTs. The main goal of the SNO+ experiment is the search for neutrinoless double beta decay of 130Te. With an initial loading of 0.3% of natural tellurium (nearly 800 kg of 130Te), it is expected to reach a sensitivity on the effective Majorana neutrino mass of about 100 meV after several years of data taking. Designed as a general purpose neutrino experiment, other exciting physical goals can be explored, like the measurement of reactor neutrino oscillations and geo-neutrinos in a geologically-interesting location, watch of supernova neutrinos and studies of solar neutrinos. A first commissioning phase with water filled detector will start at the end of 2013, while the double beta decay phase will start in 2015.

  4. Neutrinoless double beta decay search with SNO+

    Lozza V.

    2014-01-01

    Full Text Available The SNO+ experiment is the follow up of SNO. The detector is located 2 km underground in the Vale Canada Ltd.’s Creighton Mine near Sudbury, Ontario, Canada. The active volume of the detector consists of 780 tonnes of Linear Alkyl Benzene (LAB in an acrylic vessel of 12 m diameter, surrounded by about 9500 PMTs. The main goal of the SNO+ experiment is the search for neutrinoless double beta decay of 130Te. With an initial loading of 0.3% of natural tellurium (nearly 800 kg of 130Te, it is expected to reach a sensitivity on the effective Majorana neutrino mass of about 100 meV after several years of data taking. Designed as a general purpose neutrino experiment, other exciting physical goals can be explored, like the measurement of reactor neutrino oscillations and geo-neutrinos in a geologically-interesting location, watch of supernova neutrinos and studies of solar neutrinos. A first commissioning phase with water filled detector will start at the end of 2013, while the double beta decay phase will start in 2015.

  5. Average and recommended half-life values for two neutrino double beta decay: upgrade-09

    Barabash, A S

    2009-01-01

    All existing ``positive'' results on two neutrino double beta decay in different nuclei were analyzed. Using the procedure recommended by the Particle Data Group, weighted average values for half-lives of $^{48}$Ca, $^{76}$Ge, $^{82}$Se, $^{96}$Zr, $^{100}$Mo, $^{100}$Mo - $^{100}$Ru ($0^+_1$), $^{116}$Cd, $^{130}$Te, $^{150}$Nd, $^{150}$Nd - $^{150}$Sm ($0^+_1$) and $^{238}$U were obtained. Existing geochemical data were analyzed and recommended values for half-lives of $^{128}$Te, $^{130}$Te and $^{130}$Ba are proposed. We recommend the use of these results as presently the most precise and reliable values for half-lives.

  6. First neutrinoless double beta decay results from CUORE-0

    The CUORE-0 experiment, a 52 bolometer array searching for neutrinoless double beta decay from 130Te, has started taking data in spring 2013 underground at the Laboratori Nazionali del Gran Sasso (LNGS). The excellent results obtained in terms of energy resolution and background level allowed this experiment to reach the sensitivity of Cuoricino in approximately half the runtime. Combining CUORE-0 data (9.8 kg·yr exposure of 130Te) with the 19.75 kg·yr exposure of the Cuoricino experiment, we obtain the most stringent limit to date on the half-life of this isotope (T1/2 > 4.0 × 1024 yr). In this article, we review the results from CUORE-0 and discuss the status and the physics potential of CUORE, a 19 times larger bolometer array that plans to begin operations by end of this year

  7. First neutrinoless double beta decay results from CUORE-0

    Gironi, L.; Alduino, C.; Alfonso, K.; Artusa, D. R.; Avignone, F. T.; Azzolini, O.; Balata, M.; Banks, T. I.; Bari, G.; Beeman, J. W.; Bellini, F.; Bersani, A.; Biassoni, M.; Brofferio, C.; Bucci, C.; Camacho, A.; Caminata, A.; Canonica, L.; Cao, X. G.; Capelli, S.; Cappelli, L.; Carbone, L.; Cardani, L.; Carniti, P.; Casali, N.; Cassina, L.; Chiesa, D.; Chott, N.; Clemenza, M.; Copello, S.; Cosmelli, C.; Cremonesi, O.; Creswick, R. J.; Cushman, J. S.; Dafinei, I.; Dally, A.; Davis, C. J.; Dell'Oro, S.; Deninno, M. M.; Di Domizio, S.; Di Vacri, M. L.; Drobizhev, A.; Fang, D. Q.; Faverzani, M.; Fernandes, G.; Ferri, E.; Ferroni, F.; Fiorini, E.; Franceschi, M. A.; Freedman, S. J.; Fujikawa, B. K.; Giachero, A.; Giuliani, A.; Gorla, P.; Gotti, C.; Gutierrez, T. D.; Haller, E. E.; Han, K.; Hansen, E.; Heeger, K. M.; Hennings-Yeomans, R.; Hickerson, K. P.; Huang, H. Z.; Kadel, R.; Keppel, G.; Kolomensky, Yu. G.; Ligi, C.; Lim, K. E.; Liu, X.; Ma, Y. G.; Maino, M.; Martinez, M.; Maruyama, R. H.; Mei, Y.; Moggi, N.; Morganti, S.; Napolitano, T.; Nisi, S.; Nones, C.; Norman, E. B.; Nucciotti, A.; O'Donnell, T.; Orio, F.; Orlandi, D.; Ouellet, J. L.; Pagliarone, C. E.; Pallavicini, M.; Palmieri, V.; Pattavina, L.; Pavan, M.; Pessina, G.; Pettinacci, V.; Piperno, G.; Pira, C.; Pirro, S.; Pozzi, S.; Previtali, E.; Rosenfeld, C.; Rusconi, C.; Sala, E.; Sangiorgio, S.; Santone, D.; Scielzo, N. D.; Sisti, M.; Smith, A. R.; Taffarello, L.; Tenconi, M.; Terranova, F.; Tomei, C.; Trentalange, S.; Ventura, G.; Vignati, M.; Wagaarachchi, S. L.; Wang, B. S.; Wang, H. W.; Wielgus, L.; Wilson, J.; Winslow, L. A.; Wise, T.; Woodcraft, A.; Zanotti, L.; Zarra, C.; Zhang, G. Q.; Zhu, B. X.; Zimmermann, S.; Zucchelli, S.

    2015-10-01

    The CUORE-0 experiment, a 52 bolometer array searching for neutrinoless double beta decay from 130Te, has started taking data in spring 2013 underground at the Laboratori Nazionali del Gran Sasso (LNGS). The excellent results obtained in terms of energy resolution and background level allowed this experiment to reach the sensitivity of Cuoricino in approximately half the runtime. Combining CUORE-0 data (9.8 kg.yr exposure of 130Te) with the 19.75 kg.yr exposure of the Cuoricino experiment, we obtain the most stringent limit to date on the half-life of this isotope (T1/2 > 4.0 × 1024 yr). In this article, we review the results from CUORE-0 and discuss the status and the physics potential of CUORE, a 19 times larger bolometer array that plans to begin operations by end of this year.

  8. First neutrinoless double beta decay results from CUORE-0

    Gironi, L., E-mail: luca.gironi@mib.infn.it; Biassoni, M.; Brofferio, C.; Capelli, S.; Carniti, P.; Cassina, L.; Chiesa, D.; Clemenza, M.; Faverzani, M.; Ferri, E.; Gotti, C.; Maino, M.; Nucciotti, A.; Pavan, M.; Pozzi, S.; Sala, E.; Sisti, M.; Terranova, F.; Zanotti, L. [Dipartimento di Fisica, Università di Milano-Bicocca, Milano I-20126 - Italy (Italy); INFN - Sezione di Milano Bicocca, Milano I-20126 - Italy (Italy); Alduino, C. [Department of Physics and Astronomy, University of South Carolina, Columbia, SC 29208 - USA (United States); and others

    2015-10-28

    The CUORE-0 experiment, a 52 bolometer array searching for neutrinoless double beta decay from {sup 130}Te, has started taking data in spring 2013 underground at the Laboratori Nazionali del Gran Sasso (LNGS). The excellent results obtained in terms of energy resolution and background level allowed this experiment to reach the sensitivity of Cuoricino in approximately half the runtime. Combining CUORE-0 data (9.8 kg·yr exposure of {sup 130}Te) with the 19.75 kg·yr exposure of the Cuoricino experiment, we obtain the most stringent limit to date on the half-life of this isotope (T{sub 1/2} > 4.0 × 10{sup 24} yr). In this article, we review the results from CUORE-0 and discuss the status and the physics potential of CUORE, a 19 times larger bolometer array that plans to begin operations by end of this year.

  9. Nuclear matrix elements for double-{\\beta} decay

    Barea, J; Iachello, F; 10.1103/PhysRevC.87.014315

    2013-01-01

    Background: Direct determination of the neutrino mass through double-$\\beta$ decay is at the present time one of the most important areas of experimental and theoretical research in nuclear and particle physics. Purpose: We calculate nuclear matrix elements for the extraction of the average neutrino mass in neutrinoless double-$\\beta$ decay. Methods: The microscopic interacting boson model (IBM-2) is used. Results: Nuclear matrix elements in the closure approximation are calculated for $^{48}$Ca, $^{76}$Ge, $^{82}$Se, $^{96}$Zr, $^{100}$Mo, $^{110}$Pd, $^{116}$Cd, $^{124}$Sn, $^{128}$Te, $^{130}$Te, $^{148}$Nd, $^{150}$Nd, $^{154}$Sm, $^{160}$Gd, and $^{198}$Pt decay. Conclusions: Realistic predictions for the expected half-lives in neutrinoless double-$\\beta$ decay with light and heavy neutrino exchange in terms of neutrino masses are made and limits are set from current experiments.

  10. Double beta decay experiments

    Barabash, A. S.

    2011-01-01

    The present status of double beta decay experiments is reviewed. The results of the most sensitive experiments are discussed. Proposals for future double beta decay experiments with a sensitivity to the $$ at the level of (0.01--0.1) eV are considered.

  11. Exchange effects in double beta decay

    Over the past decade there has been very impressive progress in the laboratory study of double beta decay with very precise limits on 0-neutrino decay in /sup 76/Ge, the imminent prospect of the observation of 2-neutrino decay in /sup 100/Mo and the first laboratory observation of 2-neutrino decay in /sup 82/Se. For the last case, the laboratory rate is in essential agreement with geochemical results and in reasonable agreement with theoretical predictions based on a full shell model calculation. The motivation underlying the resurgence of interest in double beta decay is the hope that the observation of, or limits on the 0-neutrino mode will provide information about the nature of the neutrino. This clearly requires confidence in the nuclear matrix elements involved in the transition. The shell model calculations do not agree well with the geochemical values for /sup 130/Te, which has led to a spate of papers offering specific fixes for the problem. In this contribution we shall not comment on any of the specific nuclear calculations, rather we make some remarks which should be relevant to any model calculation. 11 refs., 1 tab

  12. Thick-target yields of iodine isotopes from proton interactions in Te, and the double-β decay of 128,130Te

    We report thick-target yields of 126,128,130I from the bombardment of natural Te targets with 15-, 30-, 45- and 50-MeV protons, together with the iodine production cross sections for 1.85- and 5.0-GeV protons. With these data, we have estimated the relative cosmic-ray induced production of 126Xe, 128Xe and 13OXe in Te ores. These quantities affect the ratio of double-β decay half-lives of 13OTe and 128Te. A revised correction of cosmic-ray induced xenon can change the half-life ratio by as much as 10%, from (3.52±0.11) x 10-4 to (3.88±0.14) x 10-4

  13. Neutrinoless double beta decay

    The physics potential of neutrinoless double beta decay is discussed. Furthermore, experimental considerations as well as the current status of experiments are presented. Finally, an outlook towards the future, work on nuclear matrix elements and alternative processes is given. (author)

  14. Neutrinoless double beta decay

    Kai Zuber

    2012-10-01

    The physics potential of neutrinoless double beta decay is discussed. Furthermore, experimental considerations as well as the current status of experiments are presented. Finally, an outlook towards the future, work on nuclear matrix elements and alternative processes is given.

  15. Double beta decay experiments

    The great sensitivity of double beta decay to neutrino mass and right handed currents has motivated many new and exciting attempts to observe this elusive nuclear phenomenon directly. Experiments in operation and other coming on line in the next one or two years are expected to result in order-of-magnitude improvements in detectable half lives for both the two-neutrino and no-neutrino modes. A brief history of double beta decay experiments is presented together with a discussion of current experimental efforts, including a gas filled time projection chamber being used to study selenium-82. (author)

  16. Precise half-life values for two neutrino double beta decay

    Barabash, A S

    2010-01-01

    All existing "positive" results on two neutrino double beta decay in different nuclei were analyzed. Using the procedure recommended by the Particle Data Group, weighted average values for half-lives of $^{48}$Ca, $^{76}$Ge, $^{82}$Se, $^{96}$Zr, $^{100}$Mo, $^{100}$Mo - $^{100}$Ru ($0^+_1$), $^{116}$Cd, $^{130}$Te, $^{150}$Nd, $^{150}$Nd - $^{150}$Sm($0^+_1$) and $^{238}$U were obtained. Existing geochemical data were analyzed and recommended values for half-lives of $^{128}$Te, $^{130}$Te and $^{130}$Ba are proposed. Given the measured half-life values, nuclear matrix elements were calculated. I recommend the use of these results as the most currently reliable values for the half-lives and nuclear matrix elements.

  17. Neutrinoless Double Beta Decay

    Päs, Heinrich

    2015-01-01

    We review the potential to probe new physics with neutrinoless double beta decay $(A,Z) \\to (A,Z+2) + 2 e^-$. Both the standard long-range light neutrino mechanism as well as short-range mechanisms mediated by heavy particles are discussed. We also stress aspects of the connection to lepton number violation at colliders and the implications for baryogenesis.

  18. Average and recommended half-life values for two neutrino double beta decay: upgrade-2013

    Barabash, A S

    2013-01-01

    All existing positive results on two neutrino double beta decay in different nuclei were analyzed. Using the procedure recommended by the Particle Data Group, weighted average values for half-lives of $^{48}$Ca, $^{76}$Ge, $^{82}$Se, $^{96}$Zr, $^{100}$Mo, $^{100}$Mo - $^{100}$Ru ($0^+_1$), $^{116}$Cd, $^{130}$Te, $^{136}$Xe, $^{150}$Nd, $^{150}$Nd - $^{150}$Sm ($0^+_1$) and $^{238}$U were obtained. Existing geochemical data were analyzed and recommended values for half-lives of $^{128}$Te and $^{130}$Ba are proposed. I recommend the use of these results as the most currently reliable values for half-lives.

  19. Average (RECOMMENDED) Half-Life Values for Two Neutrino Double Beta Decay

    Barabash, A S

    2002-01-01

    All existing "positive" results on two neutrino double beta decay in different nuclei were analyzed. Using procedure recommended by Particle Data Group weighted average values for half-lives of $^{48}$Ca, $^{76}$Ge, $^{82}$Se, $^{96}$Zr, $^{100}$Mo, $^{100}$Mo - $^{100}$Ru ($0^+_1$), $^{116}$Cd, $^{150}$Nd and $^{238}$U were obtained. Existing geochemical data were analyzed and recommended values for half-lives of $^{128}$Te and $^{130}$Te are proposed. We recommend to use these results as most precise and reliable values for half-lives at this moment.

  20. Average and recommended half-life values for two neutrino double beta decay: upgrade'05

    Barabash, A S

    2006-01-01

    All existing ``positive'' results on two neutrino double beta decay in different nuclei were analyzed. Using the procedure recommended by the Particle Data Group, weighted average values for half-lives of $^{48}$Ca, $^{76}$Ge, $^{82}$Se, $^{96}$Zr, $^{100}$Mo, $^{100}$Mo - $^{100}$Ru ($0^+_1$), $^{116}$Cd, $^{150}$Nd, $^{150}$Nd - $^{150}$Sm ($0^+_1$) and $^{238}$U were obtained. Existing geochemical data were analyzed and recommended values for half-lives of $^{128}$Te, $^{130}$Te and $^{130}$Ba are proposed. We recommend the use of these results as presently the most precise and reliable values for half-lives.

  1. Nuclear double beta decay and the evidence for lepton number non-conservation

    The reported ratio of double beta decay of the isotopes 128Te and 130Te measured by geochemical techniques, coupled with an assumed equality of the nuclear matrix elements, would indicate the existence of a neutrinoless branch indicative of lepton number violation. A large-scale shell model calculation of the nuclear matrix elements was performed; they were found to be approximately equal. However, the absolute rates calculated for the normal, two-neutrino branch alone are 49 times faster than experiment for 128Te and 156 times faster than experiment for 130Te. In a similar vein, a rate that is 18 times faster than the geochemical result is calculated for the transition 82Se → 82Kr; however, that calculation is in essential agreement with a recent counting experiment. It is argued that, until these large discrepancies are resolved, one cannot say anything definitive about lepton number violation, although the possibility that the ratio of rates is indicating a positive signal remains. It is also noted that, for the case of 76Ge → 76Se, a pure Majorana mass of 35 eV is ruled out by Fiorini's limit on neutrinoless double beta decay. 3 tables

  2. Double beta decay: present status

    Barabash, A. S.

    2008-01-01

    The present status of double beta decay experiments (including the search for $2\\beta^{+}$, EC$\\beta^{+}$ 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$ eV and $ < 1.9 \\cdot 10^{-4}$, respectively. Proposals fo...

  3. Predicting Neutrinoless Double Beta Decay

    Hirsch, M; Valle, J W F; Moral, A V; Ma, Ernest

    2005-01-01

    We give predictions for the neutrinoless double beta decay rate in a simple variant of the A_4 family symmetry model. We show that there is a lower bound for the neutrinoless double beta decay amplitude even in the case of normal hierarchical neutrino masses, corresponding to an effective mass parameter |m_{ee}| >= 0.17 \\sqrt{\\Delta m^2_{ATM}}. This result holds both for the CP conserving and CP violating cases. In the latter case we show explicitly that the lower bound on |m_{ee}| is sensitive to the value of the Majorana phase. We conclude therefore that in our scheme, neutrinoless double beta decay may be accessible to the next generation of high sensitivity experiments.

  4. Decay pattern of the Pygmy dipole resonance in 130Te

    The electric dipole strength distribution in 130Te has been investigated using the method of Nuclear Resonance Fluorescence. The experiments were performed at the Darmstadt High Intensity Photon Setup using Bremsstrahlung as photon source and at the High Intensity γ-Ray Source, where quasi-monochromatic and polarized photon beams are provided. Average decay properties of 130Te below the neutron separation energy are determined. Comparing the experimental data to the predictions of the statistical model indicate, that nuclear structure effects play an important role even at sufficiently high excitation energies. Preliminary results will be presented. (authors)

  5. Experiments on double beta decay

    Busto, J. [Neuchatel Univ. (Switzerland). Inst. de Physique

    1996-11-01

    The Double Beta Decay, and especially ({beta}{beta}){sub 0{nu}} mode, is an excellent test of Standard Model as well as of neutrino physics. From experimental point of view, a very large number of different techniques are or have been used increasing the sensitivity of this experiments quite a lot (the factor of 10{sup 4} in the last 20 years). In future, in spite of several difficulties, the sensitivity would be increased further, keeping the interest of this very important process. (author) 4 figs., 5 tabs., 21 refs.

  6. Neutron capture cross-section studies of Tellurium isotopes for neutrinoless double beta decay applications

    Bhike, Megha; Tornow, Werner

    2014-09-01

    The CUORE detector at Gran Sasso, aimed at searching for neutrinoless double-beta decay of 130Te, employs an array of TeO2 bolometer modules. To understand and identify the contribution of muon and (α,n) induced neutrons to the CUORE background, fast neutron cature cross-section data of the tellurium isotopes 126Te, 128Te and 130Te have been measured with the activation method at eight different energies in the neutron energy range 0.5-7.5 MeV. Plastic pill boxes of diameter 1.6 cm and width 1 cm containing Te were irradiated with mono-energetic neutrons produced via the 3H(p,n)3He and 2H(d,n)3He reactions. The cross-sections were determined relative to the 197Au(n, γ)198Au and 115In(n,n')115m In standard cross sections. The activities of the products were measured using 60% lead-shielded HPGe detectors at TUNL's low background counting facility. The present results are compared with the evaluated data from TENDL-2012, ENDF/B-VII.1, JEFF-3.2 and JENDL-4.0, as well as with literature data.

  7. Constraining neutrinoless double beta decay

    A class of discrete flavor-symmetry-based models predicts constrained neutrino mass matrix schemes that lead to specific neutrino mass sum-rules (MSR). We show how these theories may constrain the absolute scale of neutrino mass, leading in most of the cases to a lower bound on the neutrinoless double beta decay effective amplitude.

  8. Weak-interaction and nuclear-structure aspects of nuclear double beta decay

    Weak-interaction and nuclear-structure aspects of double beta decay are reviewed. Starting from effective electroweak lagrangians, decay rates for the two-neutrino and neutrinoless modes of the nuclear double beta decay transitions are defined and second-order perturbative expressions for the nuclear decay amplitudes are given. Nuclear matrix elements of the relevant operators are presented, as extracted from data and from shell-model and QRPA calculations as well as from other theoretical approximations. The analysis is performed both for the two-neutrino and neutrinoless modes of the decay. The expressions for ground-state-to-ground-state and ground-state-to-excited-state transitions are presented. Updated experimental and theoretical information on β-β- decays in 48Ca, 76Ge, 82Se, 96Zr, 100Mo, 116Cd, 124Sn, 128Te, 130Te, 136Xe, 150Nd, and on β+β+, β+ EC and double EC decays in 78Kr, 92Mo, 96Ru, 106Cd, 124Xe, 130Ba, 136Ce is analyzed and compared with theoretical results. The relevance of single-beta-decay transitions feeding some of the nuclei where double-beta-decay transitions occur is pointed out. The systematics of various phase-space factors and extracted matrix elements is presented. (orig.)

  9. Gamow-Teller strength distributions for double-beta-decaying nuclei within continuum-QRPA

    Igashov, S. Yu.; Rodin, V. A.; Urin, M.H.; Faessler, A.

    2007-01-01

    A version of the pn-continuum-QRPA is outlined and applied to describe the Gamow-Teller strength distributions for $\\beta\\beta$-decaying open-shell nuclei. The calculation results obtained for the pairs of nuclei $^{116}$Cd-Sn and $^{130}$Te-Xe are compared with available experimental data.

  10. Deformation and the Nuclear Matrix Elements of the Neutrinoless Double Beta Decay

    Menendez, J; Caurier, E; Nowacki, F

    2008-01-01

    In this talk I will review the "state of the art" of the calculations of the nuclear matrix elements (NME) of the neutrinoless double beta decays for the nuclei 48Ca, 76Ge, 82Se, 124Sn, 128Te, 130Te and 136Xe in the framework of the Interacting Shell Model (ISM), and compare them with the NME's obtained using the Quasi-particle RPA approach (QRPA). I will also discuss the effect of the competition between the pairing and quadrupole correlations in the value of these NME's. In particular I will show that, as the difference in deformation between parent and grand daughter grows, the NME's of both the neutrinoless and the two neutrino modes decrease rapidly.

  11. Average and recommended half-life values for two neutrino double beta decay

    Barabash, A S

    2015-01-01

    All existing positive results on two neutrino double beta decay in different nuclei were analyzed. Using the procedure recommended by the Particle Data Group, weighted average values for half-lives of $^{48}$Ca, $^{76}$Ge, $^{82}$Se, $^{96}$Zr, $^{100}$Mo, $^{100}$Mo - $^{100}$Ru ($0^+_1$), $^{116}$Cd, $^{130}$Te, $^{136}$Xe, $^{150}$Nd, $^{150}$Nd - $^{150}$Sm ($0^+_1$) and $^{238}$U were obtained. Existing geochemical data were analyzed and recommended values for half-lives of $^{128}$Te, and $^{130}$Ba are proposed. Given the measured half-life values, nuclear matrix elements were calculated using latest (more reliable and precise) values for phase space factor. Finally, previous results (PRC 81 (2010) 035501) were up-dated and results for $^{136}$Xe were added.

  12. Multipolar correlations and deformation effect on nuclear transition matrix elements of double-$\\beta $ decay

    Chandra, R; Rath, P K; Raina, P K; Hirsch, J G

    2009-01-01

    The two neutrino and neutrinoless double beta decay of $^{94,96}$Zr, $^{98,100}$Mo, $^{104}$Ru, $^{110}$Pd, $^{128,130}$Te and $^{150}$Nd isotopes for the $0^{+}\\to 0^{+}$ transition is studied within the PHFB framework along with an effective two-body interaction consisting of pairing, quadrupole-quadrupole and hexadecapole-hexadecapole correlations. It is found that the effect of hexadecapolar correlations can be assimilated substantially as a renormalization of the quadrupole-quadrupole interaction. The effect of deformation on nuclear transition matrix elements is investigated by varying the strength of quadrupolar correlations in the parent and daughter nuclei independently. The variation of the nuclear transition matrix elements as a function of the difference in deformation parameters of parent and daughter nuclei reveals that in general, the former tend to be maximum for equal deformation and they decrease as the difference in deformation parameters increases, exhibiting a very similar trend for the $...

  13. Status of the CUORE and results from the CUORE-0 neutrinoless double beta decay experiments

    Sisti, M; Avignone, F T; Azzolini, O; Balata, M; Banks, T I; Bari, G; Beeman, J; Bellini, F; Bersani, A; Biassoni, M; Brofferio, C; Bucci, C; Cai, X Z; Camacho, A; Caminata, A; Canonica, L; Cao, X G; Capelli, S; Cappelli, L; Carbone, L; Cardani, L; Casali, N; Cassina, L; Chiesa, D; Chott, N; Clemenza, M; Copello, S; Cosmelli, C; Cremonesi, O; Creswick, R J; Cushman, J S; Dafinei, I; Dally, A; Datskov, V; Dell'Oro, S; Deninno, M; Di Domizio, S; di Vacri, M L; Drobizhev, A; Ejzak, L; Fang, D Q; Farach, H A; Faverzani, M; Fernandes, G; Ferri, E; Ferroni, F; Fiorini, E; Franceschi, M A; Freedman, S J; Fujikawa, B K; Giachero, A; Gironi, L; Giuliani, A; Gorla, P; Gotti, C; Gutierrez, T D; Haller, E E; Han, K; Heeger, K M; Hennings-Yeomans, R; Hickerson, K P; Huang, H Z; Kadel, R; Keppel, G; Kolomensky, Yu G; Li, Y L; Ligi, C; Lim, K E; Liu, X; Ma, Y G; Maiano, C; Maino, M; Martinez, M; Maruyama, R H; Mei, Y; Moggi, N; Morganti, S; Napolitano, T; Nastasi, M; Nisi, S; Nones, C; Norman, E B; Nucciotti, A; O'Donnell, T; Orio, F; Orlandi, D; Ouellet, J L; Pagliarone, C E; Pallavicini, M; Palmieri, V; Pattavina, L; Pavan, M; Pedretti, M; Pessina, G; Pettinacci, V; Piperno, G; Pira, C; Pirro, S; Pozzi, S; Previtali, E; Rosenfeld, C; Rusconi, C; Sala, E; Sangiorgio, S; Scielzo, N D; Smith, A R; Taffarello, L; Tenconi, M; Terranova, F; Tian, W D; Tomei, C; Trentalange, S; Ventura, G; Vignati, M; Wang, B S; Wang, H W; Wielgus, L; Wilson, J; Winslow, L A; Wise, T; Woodcraft, A; Zanotti, L; Zarra, C; Zhang, G Q; Zhu, B X; Zucchelli, S

    2015-01-01

    CUORE is a 741 kg array of TeO2 bolometers for the search of neutrinoless double beta decay of 130Te. The detector is being constructed at the Laboratori Nazionali del Gran Sasso, Italy, where it will start taking data in 2015. If the target background of 0.01 counts/keV/kg/y will be reached, in five years of data taking CUORE will have a 1 sigma half life sensitivity of 10E26 y. CUORE-0 is a smaller experiment constructed to test and demonstrate the performances expected for CUORE. The detector is a single tower of 52 CUORE-like bolometers that started taking data in spring 2013. The status and perspectives of CUORE will be discussed, and the first CUORE-0 data will be presented.

  14. Nuclear matrix elements of neutrinoless double beta decay with improved short-range correlations

    Kortelainen, Markus

    2007-01-01

    Nuclear matrix elements of the neutrinoless double beta decays of 96Zr, 100Mo, 116Cd, 128Te, 130Te and 136Xe are calculated for the light-neutrino exchange mechanism by using the proton-neutron quasiparticle random-phase approximation (pnQRPA) with a realistic nucleon-nucleon force. The g_pp parameter of the pnQRPA is fixed by the data on the two-neutrino double beta decays and single beta decays. The finite size of a nucleon, the higher-order terms of nucleonic weak currents, and the nucleon-nucleon short-range correlations (s.r.c) are taken into account. The s.r.c. are computed by the traditional Jastrow method and by the more advanced unitary correlation operator method (UCOM). Comparison of the results obtained by the two methods is carried out. The UCOM computed matrix elements turn out to be considerably larger than the Jastrow computed ones. This result is important for the assessment of the neutrino-mass sensitivity of the present and future double beta experiments.

  15. Review of double beta experiments

    Sarazin, X.

    2012-01-01

    C13-10-22.1 International audience This paper gives a review of the double beta experimental techniques and projects, in the search for the Majorana neutrino. The purpose of this review is to detail, for each technique, the different origins of background, how they can be identified, and how they can be reduced. Advantages and limitations of the different techniques are discussed. 1. Introduction The neutrino is one of the most puzzling elementary particle with very unique properties. I...

  16. Neutrinoless Double Beta Decay Experiments

    Zuber, K.

    2014-01-01

    Neutrinoless double beta decay is the only process known so far able to test the neutrino intrinsic nature: its experimental observation would imply that the lepton number is violated by two units and prove that neutrinos have a Majorana mass components, being their own anti-particle. While several experiments searching for such a rare decay have been performed in the past, a new generation of experiments using different isotopes and techniques have recently released their results or are taki...

  17. Experiments on double beta decay

    The Double Beta Decay, and especially (ββ)0ν mode, is an excellent test of Standard Model as well as of neutrino physics. From experimental point of view, a very large number of different techniques are or have been used increasing the sensitivity of this experiments quite a lot (the factor of 104 in the last 20 years). In future, in spite of several difficulties, the sensitivity would be increased further, keeping the interest of this very important process. (author) 4 figs., 5 tabs., 21 refs

  18. Challenges in Double Beta Decay

    Oliviero Cremonesi

    2014-01-01

    Full Text Available In the past ten years, neutrino oscillation experiments have provided the incontrovertible evidence that neutrinos mix and have finite masses. These results represent the strongest demonstration that the electroweak Standard Model is incomplete and that new Physics beyond it must exist. In this scenario, a unique role is played by the Neutrinoless Double Beta Decay searches which can probe lepton number conservation and investigate the Dirac/Majorana nature of the neutrinos and their absolute mass scale (hierarchy problem with unprecedented sensitivity. Today Neutrinoless Double Beta Decay faces a new era where large-scale experiments with a sensitivity approaching the so-called degenerate-hierarchy region are nearly ready to start and where the challenge for the next future is the construction of detectors characterized by a tonne-scale size and an incredibly low background. A number of new proposed projects took up this challenge. These are based either on large expansions of the present experiments or on new ideas to improve the technical performance and/or reduce the background contributions. In this paper, a review of the most relevant ongoing experiments is given. The most relevant parameters contributing to the experimental sensitivity are discussed and a critical comparison of the future projects is proposed.

  19. Theoretical aspects of double beta decay

    Considerable effort has been expended recently in theoretical studies of double beta decay. Much of this work has focussed on the constraints this process places on gauge theories of the weak interaction, in general, and on the neutrino mass matrix, in particular. In addition, interesting nuclear structure questions have arisen in studies of double beta decay matrix elements. After briefly reviewing the theory of double beta decay, some of the progress that has been made in these areas is summarized. 25 references

  20. Tables of double beta decay data

    Tretyak, V.I. [AN Ukrainskoj SSR, Kiev (Ukraine)]|[Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires; Zdesenko, Y.G. [AN Ukrainskoj SSR, Kiev (Ukraine)

    1995-12-31

    A compilation of experimental data on double beta decay is presented. The tables contain the most stringent known experimental limits or positive results of 2{beta} transitions of 69 natural nuclides to ground and excited states of daughter nuclei for different channels (2{beta}{sup -}; 2{beta}{sup +}; {epsilon}{beta}{sup +}; 2{epsilon}) and modes (0{nu}; 2{nu}; 0{nu}M) of decay. (authors). 189 refs., 9 figs., 3 tabs.

  1. Purification of telluric acid for SNO+ neutrinoless double-beta decay search

    Hans, S.; Rosero, R.; Hu, L. [Brookhaven National Laboratory, Upton, NY 11973 (United States); Chkvorets, O. [Laurentian University, Sudbury (Canada); Chan, W.T.; Guan, S.; Beriguete, W. [Brookhaven National Laboratory, Upton, NY 11973 (United States); Wright, A. [Queen University, Kingston (Canada); Ford, R. [SNOLAB, Creighton Mine, Sudbury (Canada); Chen, M.C. [Queen University, Kingston (Canada); Biller, S. [University of Oxford, Oxford OX1 3RH (United Kingdom); Yeh, M., E-mail: yeh@bnl.gov [Brookhaven National Laboratory, Upton, NY 11973 (United States)

    2015-09-21

    Tellurium-130 has the highest natural abundance of any double-beta decay isotopes. Recently it has been developed as a promising candidate for loading in liquid scintillator to explore the Majorana or Dirac nature of the neutrino through a search for neutrinoless double beta decay (0νββ). To this end, procedures have been developed to transfer tellurium ions into the organic liquid by a water-based loading technology. However, traces of naturally occurring radioactivity and cosmic-ray induced isotopes introduced into the scintillator with tellurium could produce undesirable contaminations in the {sup 130}Te 0νββ region. Measurements using various elemental spikes prepared from different chemical forms indicate that the uses of self-scavenging as well as acid and thermal recrystallization prior to the preparation of a tellurium-loaded liquid scintillator can deplete U and Th and several cosmic-activated isotopes from Te feedstock by a factor of 10{sup 2}–10{sup 3} in a single pass. The process is also found to improve the optical transmission in the blue region, sensible to the photomultiplier tube, by removing traces of colored impurities. In addition to the scintillator-based experiments, this cleansing scheme has potential applications to the production of radiopure tellurium crystals for other rare-event experiments.

  2. The search for neutrinoless double beta decay

    Gomez-Cadenas, J J; Mezzetto, M; Monrabal, F; Sorel, M

    2011-01-01

    In the last few years the search for neutrinoless double beta decay has evolved from being almost a marginal activity in neutrino physics to one of the highest priorities for understanding neutrinos and the origin of mass. There are two main reasons for this paradigm shift: the discovery of neutrino oscillations, which clearly established the existence of massive neutrinos; and the existence of an unconfirmed, but not refuted, claim of evidence for neutrinoless double decay in 76Ge. As a consequence, a new generation of experiments, employing different detection techniques and {\\beta}{\\beta} isotopes, is being actively promoted by experimental groups across the world. In addition, nuclear theorists are making remarkable progress in the calculation of the neutrinoless double beta decay nuclear matrix elements, thus eliminating a substantial part of the theoretical uncertainties affecting the particle physics interpretation of this process. In this report, we review the main aspects of the double beta decay pro...

  3. Falsifying Baryogenesis with Neutrinoless Double Beta Decay

    Graf, Lukas

    2016-01-01

    We discuss the relation between lepton number violation at high and low energies, particularly, the constraints on baryogenesis models, which would be implied by an observation of neutrinoless double beta decay. The primordial baryon asymmetry can be washed out by effective lepton number violating operators triggering neutrinoless double beta decay in combination with sphaleron processes. A generic conclusion is that popular models of baryogenesis are excluded if a non-standard mechanism of neutrinoless double beta decay, i.e., other than the standard light neutrino exchange, is observed. Apart from the effective field approach, we also outline the possible extension of our arguments to a general UV-completed model.

  4. Review of modern double beta decay experiments

    Barabash, A. S.

    2015-10-01

    The review of modern experiments on search and studying of double beta decay processes is done. Results of the most sensitive current experiments are discussed. The main attention is paid to EXO-200, KamLAND-Zen, GERDA-I and CUORE-0 experiments. Modern values of T1/2(2ν) and best present limits on neutrinoless double beta decay and double beta decay with Majoron emission are presented. Conservative limits on effective mass of a Majorana neutrino ( at the level of ˜ 0.01-0.1 eV are discussed.

  5. The cryostat of the CUORE Project, a 1-ton scale cryogenic experiment for Neutrinoless Double Beta Decay Research

    CUORE is a new generation of 1-ton scale cryogenic detector for rare-events physics. CUORE, a detector to search Neutrinoless Double Beta Decay of 130Te, is an array of 988 TeO2 crystals of a mass of 750 g each. To build the cryogenic system, where the CUORE detector will be installed in the Gran Sasso Underground Laboratory, is really a challenge. It is a large cryogen-free cryostat cooled by pulse tubes and by a high power dilution refrigerator. To avoid radioactive background, about 10000 kg of lead will be cooled to below 1 K and only few construction materials are acceptable. the detector will have a total mass of about 1500 kg and must be cooled to less than 10 mK in a vibration-free environment.

  6. The cryostat of the CUORE Project, a 1-ton scale cryogenic experiment for Neutrinoless Double Beta Decay Research

    Schaeffer, David; Nucciotti, Angelo [Dip. di Fisica ' G. Occhialini' , Univ and INFN Sez di Milano-Bicocca, Milano (Italy); Alessandria, Franco [INFN Sez di Milano, Milano (Italy); Ardito, Raffaele [Dip. di Ingegneria Strutturale, Politecnico di Milano, Milano (Italy); Barucci, Marco; Risegari, Lara; Ventura, Guglielmo [Dip. di Fisica, Univ di Firenze and INFN Sez di Firenze, Firenze (Italy); Bucci, Carlo [INFN Laboratori Nazionali del Gran Sasso, Assergi (Italy); Frossati, Giorgio [Leiden Cryogenics, Leiden (Netherlands); Olcese, Marco [INFN Sez di Genova, Genova (Italy); Waard, Arlette de [Kamerlingh Onnes Laboratory, Leiden University, Leiden (Netherlands)], E-mail: david.schaeffer@mib.infn.it

    2009-02-01

    CUORE is a new generation of 1-ton scale cryogenic detector for rare-events physics. CUORE, a detector to search Neutrinoless Double Beta Decay of {sup 130}Te, is an array of 988 TeO{sub 2} crystals of a mass of 750 g each. To build the cryogenic system, where the CUORE detector will be installed in the Gran Sasso Underground Laboratory, is really a challenge. It is a large cryogen-free cryostat cooled by pulse tubes and by a high power dilution refrigerator. To avoid radioactive background, about 10000 kg of lead will be cooled to below 1 K and only few construction materials are acceptable. the detector will have a total mass of about 1500 kg and must be cooled to less than 10 mK in a vibration-free environment.

  7. Cosmogenic-neutron activation of TeO2 and implications for neutrinoless double-beta decay experiments

    Wang, Barbara S; Scielzo, Nicholas D; Smith, Alan R; Thomas, Keenan J; Wender, Stephen A

    2015-01-01

    Flux-averaged cross sections for cosmogenic-neutron activation of natural tellurium were measured using a neutron beam containing neutrons of kinetic energies up to $\\sim$800 MeV, and having an energy spectrum similar to that of cosmic-ray neutrons at sea-level. Analysis of the radioisotopes produced reveals that 110mAg will be a dominant contributor to the cosmogenic-activation background in experiments searching for neutrinoless double-beta decay of 130Te, such as CUORE and SNO+. An estimate of the cosmogenic-activation background in the CUORE experiment has been obtained using the results of this measurement and cross-section measurements of proton activation of tellurium. Additionally, the measured cross sections in this work are also compared with results from semi-empirical cross-section calculations.

  8. Review of modern double beta decay experiments

    The review of modern experiments on search and studying of double beta decay processes is done. Results of the most sensitive current experiments are discussed. The main attention is paid to EXO-200, KamLAND-Zen, GERDA-I and CUORE-0 experiments. Modern values of T1/2(2ν) and best present limits on neutrinoless double beta decay and double beta decay with Majoron emission are presented. Conservative limits on effective mass of a Majorana neutrino (〈mν〉 < 0.46 eV) and a coupling constant of Majoron to neutrino (〈gee〉 < 1.3 · 10−5) are obtained. Prospects of search for neutrinoless double beta decay in new experiments with sensitivity to 〈mν〉 at the level of ∼ 0.01-0.1 eV are discussed

  9. Neutrino potential for neutrinoless double beta decay

    Iwata, Yoritaka

    2016-01-01

    Neutrino potential for neutrinoless double beta decay is studied with focusing on its statistical property. The statistics provide a gross view of understanding amplitude of constitutional components of the nuclear matrix element.

  10. Review of modern double beta decay experiments

    Barabash, A. S., E-mail: barabash@itep.ru [Institute of Theoretical and Experimental Physics (NRC ”Kurchatov Institute”), B. Cheremushkinskaya 25, Moscow (Russian Federation)

    2015-10-28

    The review of modern experiments on search and studying of double beta decay processes is done. Results of the most sensitive current experiments are discussed. The main attention is paid to EXO-200, KamLAND-Zen, GERDA-I and CUORE-0 experiments. Modern values of T{sub 1/2}(2ν) and best present limits on neutrinoless double beta decay and double beta decay with Majoron emission are presented. Conservative limits on effective mass of a Majorana neutrino (〈m{sub ν}〉 < 0.46 eV) and a coupling constant of Majoron to neutrino (〈g{sub ee}〉 < 1.3 · 10{sup −5}) are obtained. Prospects of search for neutrinoless double beta decay in new experiments with sensitivity to 〈m{sub ν}〉 at the level of ∼ 0.01-0.1 eV are discussed.

  11. Searches for neutrinoless double beta decay

    Schwingenheuer, Bernhard

    2012-07-01

    Neutrinoless double beta decay is a lepton number violating process whose observation would also establish that neutrinos are their own anti-particles. There are many experimental efforts with a variety of techniques. Some (EXO, Kamland-Zen, GERDA phase I and CANDLES) started take data in 2011 and EXO has reported the first measurement of the half life for the double beta decay with two neutrinos of 136Xe. The sensitivities of the different proposals are reviewed.

  12. Searches for neutrinoless double beta decay

    Schwingenheuer, B

    2012-01-01

    Neutrinoless double beta decay is a lepton number violating process whose observation would also establish that neutrinos are their own anti-particles. There are many experimental efforts with a variety of techniques. Some (EXO, Kamland-Zen, GERDA phase I and CANDLES) started take data in 2011 and EXO has reported the first measurement of the half life for the double beta decay with two neutrinos of $^{136}$Xe. The sensitivities of the different proposals are reviewed.

  13. Nuclear physics issues in double beta decay

    A number of issues in double beta decay are discussed: shell model estimates of 2nu matrix elements, a sum rule for the double Gamow-Teller operator, a comparison of shell model and quasiparticle RPA results, Pontecorvo's Te ratio argument, neutrinoless ββ decay mediated by heavy neutrinos, and the structure of O+ states in Ge isotopes. 24 refs., 3 figs

  14. Neutron Interactions in the CUORE Neutrinoless Double Beta Decay Experiment

    Dolinski, M J

    2008-09-24

    Neutrinoless double beta decay (0{nu}DBD) is a lepton-number violating process that can occur only for a massive Majorana neutrino. The search for 0{nu}DBD is currently the only practical experimental way to determine whether neutrinos are identical to their own antiparticles (Majorana neutrinos) or have distinct particle and anti-particle states (Dirac neutrinos). In addition, the observation of 0{nu}DBD can provide information about the absolute mass scale of the neutrino. The Cuoricino experiment was a sensitive search for 0{nu}DBD, as well as a proof of principle for the next generation experiment, CUORE. CUORE will search for 0{nu}DBD of {sup 130}Te with a ton-scale array of unenriched TeO{sub 2} bolometers. By increasing mass and decreasing the background for 0{nu}DBD, the half-life sensitivity of CUORE will be a factor of twenty better than that of Cuoricino. The site for both of these experiments is the Laboratori Nazionali del Gran Sasso, an underground laboratory with 3300 meters water equivalent rock overburden and a cosmic ray muon attenuation factor of 10{sup -6}. Because of the extreme low background requirements for CUORE, it is important that all potential sources of background in the 0{nu}DBD peak region at 2530 keV are well understood. One potential source of background for CUORE comes from neutrons, which can be produced underground both by ({alpha},n) reactions and by fast cosmic ray muon interactions. Preliminary simulations by the CUORE collaboration indicate that these backgrounds will be negligible for CUORE. However, in order to accurately simulate the expected neutron background, it is important to understand the cross sections for neutron interactions with detector materials. In order to help refine these simulations, I have measured the gamma-ray production cross sections for interactions of neutrons on the abundant stable isotopes of Te using the GEANIE detector array at the Los Alamos Neutron Science Center. In addition, I have used

  15. Recent double beta decay results

    Balysh, A. (Kurchatov Institute, 123 182 Moscow (Russian Federation)); Beck, M. (Max-Planck-Institut fuer Kernphysik, W-6900 Heidelberg (Germany)); Belyaev, S.T. (Kurchatov Institute, 123 182 Moscow (Russian Federation)); Bensch, F.; Bockholt, J. (Max-Planck-Institut fuer Kernphysik, W-6900 Heidelberg (Germany)); Demehin, A.; Gurov, A. (Kurchatov Institute, 123 182 Moscow (Russian Federation)); Heusser, G.; Hirsch, M.; Klapdor-Kleingrothaus, H.V. (Max-Planck-Institut fuer Kernphysik, W-6900 Heidelberg (Germany)); Kondratenko, I.; Lebedev, V.I. (Kurchatov Institute, 123 182 Moscow (Russian Federation)); Maier, B. (Max-Planck-Institut fuer Kernphysik, W-6900 Heidelberg (Germany)); Mueller, A. (Istituto Nazionale di Fisica Nucleare LNGS, 67010 Assergi (Italy)); Petry, F.; Piepke, A.; Strecker, H.; Voellinger, M.; Zuber, K. (Max-Planck-Institut fuer Kernphysik, W-6900 Heidelberg (Germany))

    1992-02-01

    The status and recent results of second generation [beta][beta]-experiments using isotopically enriched source materials are described. These experiments are at present the most sensitive tools to distinguish Dirac from Majorana neutrinos. The at present most advanced experimental techniques, namely the use of high-resolution calorimetric detectors and of time projection chambers are compared. New limits on the Majorana neutrino mass as well as for the Majoron-neutrino coupling are presented.

  16. Gamma-ray spectroscopy of 120-130Te nuclei

    Complete text of publication follows. Structure of the even 120-130Te nuclei have been investigated with prompt gamma-ray spectroscopy following the 122-126,natTe(n,n'γ) reactions and the (α,2nγ)120,124,126Te reactions. Gamma-ray excitation functions, angular distributions, γγ-coincidences, and Doppler shifts have been measured. Level schemes have been constructed to approximately 3.3 MeV excitation energy, and spectroscopic information including level spins and parities, branching and multipole-mixing ratios, and lifetimes have been extracted. Three different types of structure are thought to play an important role in these low-lying excitations. These are: collective, two-particle, and 4p-2h intruder excitations. Because there are seven stable even-even Te nuclei, the evolution of these excitation modes over this wide range in neutron number is investigated. Level sequences and transition rates obtained from these measurements are compared to IBM-2 model calculations both with and without intruder-state mixing by Rikovska et al. (1), and to particle-vibrational coupling model calculations by Lopac (2). The IBM-2 model calculations with intruder mixing well reproduce the level energies in the low-mass Te; however, examination of the electromagnetic transition rates reveals that there is no clear improvement in the description of these nuclei by adding the intruder configurations. Additionally, no evidence of the 2+ mixed-symmetry strength is observed in the 23+ and 24+ levels in these nuclei. The particle-vibration model calculations appear to do a good job describing both the level scheme and the transition rates in the heavier nuclei investigated. (author)

  17. Neutrinoless double beta decay from lattice QCD

    Nicholson, Amy; Chang, Chia Cheng; Clark, M A; Joo, Balint; Kurth, Thorsten; Rinaldi, Enrico; Tiburzi, Brian; Vranas, Pavlos; Walker-Loud, Andre

    2016-01-01

    While the discovery of non-zero neutrino masses is one of the most important accomplishments by physicists in the past century, it is still unknown how and in what form these masses arise. Lepton number-violating neutrinoless double beta decay is a natural consequence of Majorana neutrinos and many BSM theories, and many experimental efforts are involved in the search for these processes. Understanding how neutrinoless double beta decay would manifest in nuclear environments is key for understanding any observed signals. In these proceedings we present an overview of a set of one- and two-body matrix elements relevant for experimental searches for neutrinoless double beta decay, describe the role of lattice QCD calculations, and present preliminary lattice QCD results.

  18. Double-Beta Decay at TUNL

    Kidd, Mary

    2007-10-01

    Studying double-beta decay at Triangle Universities Nuclear Laboratory (TUNL) is perhaps one of the most promising ways to pinpoint the neutrino mass. What they do not mention is that to study double-beta decay, you probably have to become a certified miner, and if you have a fear of goats, you should stay away. In this talk, I will tell you some of my experiences as a TUNL graduate student, and how I am now nearly qualified for a job in the mining industry.

  19. Why search for double beta decay?

    Searching for neutrinoless double beta decay is the only known practical method for trying to determine whether neutrinos are their own antiparticles. The theoretical motivation for supposing that they may indeed be their own antiparticles is described. The reason that it is so difficult to ascertain experimentally whether they are or are not is explained, as is the special sensitivity of neutrinoless double beta decay. The potential implications of the observation of this reaction for neutrino mass and for the physics of neutrinos is discussed

  20. Semiconductor detectors and double beta decay

    The underlying theory of double beta decay is discussed as well as some experimental observations. A class of second generation 76Ge detector experiments is then discussed. The design and physics considerations involved in the system used by LBL are explained, particularly the means of rejecting background activity. 24 references, 18 figures, 3 tables

  1. LHC dijet constraints on double beta decay

    Helo, J C

    2015-01-01

    We use LHC dijet data to derive constraints on neutrinoless double beta decay. Upper limits on cross sections for the production of "exotic" resonances, such as a right-handed W boson or a diquark, can be converted into lower limits on the double beta decay half-life for fixed choices of other parameters. Constraints derived from run-I data are already surprisingly strong and complementary to results from searches using same-sign dileptons plus jets. For the case of the left-right symmetric model, in case no new resonance is found in future runs of the LHC and assuming $g_L=g_R$, we estimate a lower limit on the double beta decay half-live larger than $10^{27}$ ys can be derived from future dijet data, except in the window of relatively light right-handed neutrino masses in the range $0.5$ MeV to $50$ GeV. Part of this mass window will be tested in the upcoming SHiP experiment. We also discuss current and future limits on possible scalar diquark contributions to double beta decay that can be derived from dije...

  2. Double beta decay: A theoretical overview

    Rosen, S.P.

    1988-01-01

    This paper reviews the theoretical possibility of double beta decay. The titles of the main sections of this paper are: Nuclear physics setting; Particle physics requirements; Kinematical features of the decay modes; Nuclear matrix elements; the Shell model and two-neutrino decay; Quasi-particle random phase approximation; and Future considerations. 18 refs., 7 tabs. (LSP)

  3. Lepton nonconservation and double beta decay

    This paper reviews the status of double beta decay as a test of lepton number conservation. Present limits on the mass of a Majorana neutrino are in the range of 10 to 50 eV. Experiments now in progress should substantially improve these limits

  4. Long term prospects for double beta decay

    Zuber, K.

    2010-01-01

    In rather general terms the long term perspective of double beta decay is discussed. All important experimental parameters are investigated as well as the status of nuclear matrix element issues. The link with other neutrino physics results and options to disentangle the underlying physics process are presented.

  5. Nuclear-Structure Data Relevant to Neutinoless-Double-Beta-Decay Matrix Elements

    Kay, Benjamin

    2015-10-01

    An observation of neutrinoless double beta decay is one of the most exciting prospects in contemporary physics. It follows that calculations of the nuclear matrix elements for this process are of high priority. The change in the wave functions between the initial and final states of the neutrinoless-double-beta-decay candidates 76Ge-->76Se, 100Mo-->100Ru, 130Te-->130Xe, and 136Xe-->136Ba have been studied with transfer reactions. The data are focused on the change in the occupancies of the valence orbitals in the ground states as two neutrons decay into two protons. The results set a strict constraint on any theoretical calculations describing this rearrangement and thus on the magnitude of the nuclear matrix elements for this process, which currently exhibit uncertainties at the factor of 2-4 level. Prior to these measurements there were limited experimental data were available A = 76 and 100 systems, and very limited data for the A = 130 and 136 systems, in a large part due to the gaseous Xe isotopes involved. The uncertainties on most of these data are estimated to range from 0.1-0.3 nucleons. The program started with the A = 76 system, with subsequent calculations, modified to reproduce the experimental occupancies, exhibiting a significant reduction in the discrepancy between various models. New data are available for the A = 100 , 130, and 136 systems. I review the program, making detailed comparisons between the latest theoretical calculations and the experimental data where available. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, under Contract Number DE-AC02-06CH11357.

  6. Double-beta decay in deformed nuclei

    A brief review of theoretical results for the double-beta decay and the double-electron capture in heavy deformed nuclei is presented. The ββ half life of 160Gd is evaluated using an extended version of the pseudo SU(3) model. While the 2ν mode is forbidden when the most probable occupations are considered, states with different occupation numbers can be mixed through the pairing interaction. The amount of this mixing is calculated using perturbation theory. The possibility of observing the ββ decay in 160Gd is discussed for both the 2ν and 0ν modes. (author)

  7. JUNO and neutrinoless double beta decay

    Ge, Shao-Feng; Rodejohann, Werner

    2015-11-01

    We study the impact of the precision determination of oscillation parameters in the JUNO experiment on half-life predictions for neutrinoless double beta decay. We show that the solar neutrino mixing angle can be measured by JUNO with below 1% uncertainty. This implies in particular that the minimal value of the effective mass in the inverted mass ordering will be known essentially without uncertainty. We demonstrate that this reduces the range of half-life predictions in order to test this value by a factor of 2. The remaining uncertainty is caused by nuclear matrix elements. This has important consequences for future double beta decay experiments that aim at ruling out the inverted mass ordering or the Majorana nature of neutrinos.

  8. JUNO and Neutrinoless Double Beta Decay

    Ge, Shao-Feng

    2015-01-01

    We study the impact of the precision determination of oscillation parameters in the JUNO experiment on half-life predictions for neutrinoless double beta decay. We show that the solar neutrino mixing angle can be measured by JUNO with below 1% uncertainty. This implies in particular that the minimal value of the effective mass in the inverted mass ordering will be known essentially without uncertainty. We demonstrate that this reduces the range of half-life predictions in order to test this value by a factor of two. The remaining uncertainty is caused by nuclear matrix elements. This has important consequences for future double beta decay experiments that aim at ruling out the inverted mass ordering or the Majorana nature of neutrinos.

  9. Importance of neutrinoless double beta decay

    Sarkar, Utpal

    2007-01-01

    A natural explanation for the smallness of the neutrino mass requires them to be Majorana particles violating lepton number by two units. Since lepton number violation can have several interesting consequences in particle physics and cosmology, it is of utmost importance to find out if there is lepton number violation in nature and what is its magnitude. The neutrinoless double beta decay experiment can answer these questions: if there is lepton number violation and if neutrinos are Majorana particles. In addition, the magnitude of neutrinoless double beta decay will constrain any other lepton number violating processes. This lepton number violation may also be relatd to the matter-antimatter asymmetry of the universe, dark matter and cosmological constant.

  10. Search for Neutrinoless Double-Beta Decay

    Tornow, Werner

    2014-01-01

    After the pioneering work of the Heidelberg-Moscow (HDM) and International Germanium Experiment (IGEX) groups, the second round of neutrinoless double-$\\beta$ decay searches currently underway has or will improve the life-time limits of double-$\\beta$ decay candidates by a factor of two to three, reaching in the near future the $T_{1/2} = 3 \\times 10^{25}$ yr level. This talk will focus on the large-scale experiments GERDA, EXO-200, and KamLAND-Zen, which have reported already lower half-life time limits in excess of $10^{25}$ yr. Special emphasis is given to KamLAND-Zen, which is expected to approach the inverted hierarchy regime before future 1-ton experiments probe completely this life-time or effective neutrino-mass regime, which starts at $\\approx 2 \\times 10^{26}$ yr or $\\approx 50$ meV.

  11. Tables of double beta decay data

    A compilation of experimental data on double beta decay is presented. The tables contain the most stringent known experimental limits or positive results of 2β transitions of 69 natural nuclides to ground and excited states of daughter nuclei for different channels (2β-; 2β+; εβ+; 2ε) and modes (0ν; 2ν; 0νM) of decay. (authors). 189 refs., 9 figs., 3 tabs

  12. JUNO and Neutrinoless Double Beta Decay

    Ge, Shao-Feng; Rodejohann, Werner

    2015-01-01

    We study the impact of the precision determination of oscillation parameters in the JUNO experiment on half-life predictions for neutrinoless double beta decay. We show that the solar neutrino mixing angle can be measured by JUNO with below 1% uncertainty. This implies in particular that the minimal value of the effective mass in the inverted mass ordering will be known essentially without uncertainty. We demonstrate that this reduces the range of half-life predictions in order to test this v...

  13. NEUTRINOLESS DOUBLE BETA DECAY: AN EXTREME CHALLENGE

    Fernando Ferroni

    2013-01-01

    Neutrino-less Double Beta Decay is the only known way to possibly resolve the nature of neutrino mass. The chances to cover the mass region predicted by the inverted hierarchy require a step forward in detector capability. A possibility is to make use of scintillating bolometers. These devices shall have a great power in distinguishing signals from alfa particles from those induced by electrons. This feature might lead to an almost background-free experiment. Here the Lucifer concept will be ...

  14. Simulation in double-beta decay experiments

    A detailed understanding of background radiation sources is a key to interpretation and enhanced sensitivity of double-beta decay experiments. Improvement of several techniques will be discussed. An implementation of the EGS4 code was developed to improve the accuracy of detector simulations, in particular for a 100Mo double-beta decay experiment. The efficiency modification due to the angular dependence of the 539 keV - 590 keV gamma-ray coincidence was successfully determined. The success of the 100Mo effort led to the modeling of uranium-thorium backgrounds found in an electroformed copper shield built for a 76Ge experiment. The large copper mass increased our sensitivity to contaminants present in copper produced this way, and led to changes in our cryostat electroforming technique. The original goal was the determination of the 210Pb content of the 450 year old lead shield previously used in 71Ge two-neutrino double-beta decay measurements. The results pertaining to low background materials and fabrication techniques will also be discussed

  15. A background free double beta decay experiment

    Giomataris, Ioannis

    2010-01-01

    We present a new detection scheme for rejecting backgrounds in neutrino less double beta decay experiments. It relies on the detection of Cherenkov light emitted by electrons in the MeV region. The momentum threshold is tuned to reach a good discrimination between background and good events. We consider many detector concepts and a range of target materials. The most promising is a high-pressure 136Xe emitter for which the required energy threshold is easily adjusted. Combination of this concept and a high pressure Time Projection Chamber could provide an optimal solution. A simple and low cost effective solution is to use the Spherical Proportional Counter that provides two delayed signals from ionization and Cherenkov light. In solid-state double beta decay emitters, because of their higher density, the considered process is out of energy range. An alternative solution could be the development of double decay emitters with lower density by using for instance the aerogel technique. It is surprising that a te...

  16. The high sensitivity double beta spectrometer TGV

    Briancon, Ch.; Brudanin, V. B.; Egorov, V. G.; Janout, Z.; Koníček, J.; Kovalík, A.; Kovalenko, V. E.; Kubašta, J.; Pospíšil, S.; Revenko, A. V.; Rukhadze, N. I.; Salamatin, A. V.; Sandukovsky, V. G.; Štekl, I.; Timkin, V. V.; Tsupko-Sitnikov, V. V.; Vorobel, V.; Vylov, Ts.

    1996-02-01

    A high sensitivity double beta spectrometer TGV (Telescope Germanium Vertical) has been developed. It is based on 16 HPGe detectors of volume 1200 × 6 mm 3 each in the same cryostat. The TGV spectrometer was proposed for the study of ultrarare nuclear processes (e.g. 2νββ, 0νββ, 2νEC/EC). Details of the TGV spectrometer construction are described, the principles of background suppression, the results of Monte Carlo simulations and the results of test background measurements (in Dubna and Modane underground laboratory) are provided.

  17. The high sensitivity double beta spectrometer TGV

    A high sensitivity double beta spectrometer TGV (Telescope Germanium Vertical) has been developed. It is based on 16 HPGe detectors of volume 1200 x 6 mm3 each in the same cryostat. The TGV spectrometer was proposed for the study of ultrarare nuclear processes (e.g. 2νββ, 0νββ, 2νEC/EC). Details of the TGV spectrometer construction are described, the principles of background suppression, the results of Monte Carlo simulations and the results of test background measurements (in Dubna and Modane underground laboratory) are provided. (orig.)

  18. NEUTRINOLESS DOUBLE BETA DECAY: AN EXTREME CHALLENGE

    Fernando Ferroni

    2013-12-01

    Full Text Available Neutrino-less Double Beta Decay is the only known way to possibly resolve the nature of neutrino mass. The chances to cover the mass region predicted by the inverted hierarchy require a step forward in detector capability. A possibility is to make use of scintillating bolometers. These devices shall have a great power in distinguishing signals from alfa particles from those induced by electrons. This feature might lead to an almost background-free experiment. Here the Lucifer concept will be introduced and the prospects related to this project will be discussed.

  19. The NEXT double beta decay experiment

    Laing, A.; NEXT Collaboration

    2016-05-01

    NEXT (Neutrino Experiment with a Xenon TPC) is a neutrinoless double-beta (ββ0v) decay experiment at Laboratorio Subterraneo de Canfranc (LSC). It is an electroluminescent Time Projection Chamber filled with high pressure 136Xe gas with separated function capabilities for calorimetry and tracking. Energy resolution and background suppression are the two key features of any neutrinoless double beta decay experiment. NEXT has both good energy resolution (handle for background identification provided by track reconstruction. We expect a background rate of 4 × 10-4 counts keV-1 kg-1 yr-1, and a sensitivity to the Majorana neutrino mass of between 80-160 meV (depending on NME) after a run of 3 effective years of the 100 kg scale NEXT-100 detector. The initial phase of NEXT-100, called NEW, is currently being commissioned at LSC. It will validate the NEXT background rate expectations and will make first measurements of the two neutrino ββ2v mode of 136Xe. Furthermore, the NEXT technique can be extrapolated to the tonne scale, thus allowing the full exploration of the inverted hierarchy of neutrino masses. These proceedings review NEXT R&D results, the status of detector commissioning at LSC and the NEXT physics case.

  20. Probing new physics in the neutrinoless double beta decay using electron angular correlation

    The angular correlation of the electrons emitted in the neutrinoless double beta decay (0ν2β) is presented using a general Lorentz invariant effective Lagrangian for the leptonic and hadronic charged weak currents. We show that the coefficient K in the angular correlation dΓ/dcosθ∝(1-Kcosθ) is essentially independent of the nuclear matrix element models and present its numerical values for the five nuclei of interest (76Ge, 82Se, 100Mo, 130Te, and 136Xe), assuming that the 0ν2β decays in these nuclei are induced solely by a light Majorana neutrino, νM. This coefficient varies between K=0.81 (for the 76Ge nucleus) and K=0.88 (for the 82Se and 100Mo nuclei), calculated taking into account the effects from the nucleon recoil, the S and P waves for the outgoing electrons and the electron mass. Deviation of K from its values derived here would indicate the presence of new physics (NP) in addition to a light Majorana neutrino, and we work out the angular coefficients in several νM+NP scenarios for the 76Ge nucleus. As an illustration of the correlations among the 0ν2β observables (half-life T1/2, the coefficient K, and the effective Majorana neutrino mass ||) and the parameters of the underlying NP model, we analyze the left-right symmetric models, taking into account current phenomenological bounds on the right-handed WR-boson mass and the left-right mixing parameter ζ

  1. Searching for the Dirac nature of neutrinos: combining neutrinoless double beta decay and neutrino mass measurements

    Establishing the nature of neutrinos, whether they are Dirac or Majorana particles, is one of the fundamental questions we need to answer in particle physics as it is related to the conservation of the lepton number. Neutrinoless double beta decay (ββ0ν) is the tool of choice for testing the Majorana nature of neutrinos. Up to now, this process has not been observed, but a wide experimental effort is taking place worldwide and soon new results will become available. Different mechanisms can induce (ββ0ν) decay and might interfere with each other, potentially leading to suppressed contributions to the decay rate. This possibility would become of great interest if upcoming neutrino mass measurements from KATRIN and cosmological observations found that mν > 0.2 eV but no positive signal was observed in (ββ0ν)-decay experiments. We focus on the possible interference between light Majorana neutrino exchange with other mechanisms, such as heavy sterile neutrinos. We show that in some cases the use of different nuclei would allow the disentanglement of the different contributions and allow us to test the hypothesis of destructive interference. For example, if an exact cancellation takes place in the decay of 76Ge, 130Te is suggested to be a good candidate for testing the contribution of lepton-number violating mechanisms in ββ0ν decay, while the use of 82Se would not provide additional information. Finally, we present a model in which such interference can emerge and we discuss the range of parameters which would lead to a significant suppression of the decay rate. (authors)

  2. Probing new physics in the neutrinoless double beta decay using electron angular correlation

    The angular correlation of the electrons emitted in the neutrinoless double beta decay (0ν2β) is presented using a general Lorentz invariant effective Lagrangian for the leptonic and hadronic charged weak currents. We show that the coefficient K in the angular correlation dΓ/dcos θ ∝(1-K cos θ) is essentially independent of the nuclear matrix element models and present its numerical values for the five nuclei of interest (76Ge, 82Se, 100Mo, 130Te, and 136Xe), assuming that the 0ν2β-decays in these nuclei are induced solely by a light Majorana neutrino, νM. This coefficient varies between K=0.82 (for the 76Ge nucleus) and K=0.88 (for the 82Se and 100Mo nuclei), calculated taking into account the effects from the nucleon recoil, the S and P-waves for the outgoing electrons and the electron mass. Deviation of K from its values derived here would indicate the presence of New Physics (NP) in addition to a light Majorana neutrino, and we work out the angular coefficients in several νM+NP scenarios for the 76Ge nucleus. As an illustration of the correlations among the 0ν2β observables (half-life T1/2, the coefficient K, and the effective Majorana neutrino mass vertical stroke left angle m right angle vertical stroke) and the parameters of the underlying NP model, we analyze the left-right symmetric models, taking into account current phenomenological bounds on the right-handed WR-boson mass and the left-right mixing parameter ζ. (orig.)

  3. COBRA - Double beta decay searches using CdTe detectors

    Zuber, K.

    2001-01-01

    A new approach (called COBRA) for investigating double beta decay using CdTe (CdZnTe) semiconductor detectors is proposed. It follows the idea that source and detector are identical. This will allow simultaneous measurements of 5 $\\beta^-\\beta^-$ - and 4 $\\beta^+\\beta^+$ - emitters at once. Half-life limits for neutrinoless double beta decay of Cd-116 and Te-130 can be improved by more than one order of magnitude with respect to current limits and sensitivities on the effective Majorana neutr...

  4. Neutrinoless Double Beta Decay: 2015 Review

    Stefano Dell’Oro

    2016-01-01

    Full Text Available The discovery of neutrino masses through the observation of oscillations boosted the importance of neutrinoless double beta decay (0νββ. In this paper, we review the main features of this process, underlining its key role from both the experimental and theoretical point of view. In particular, we contextualize the 0νββ in the panorama of lepton number violating processes, also assessing some possible particle physics mechanisms mediating the process. Since the 0νββ existence is correlated with neutrino masses, we also review the state of the art of the theoretical understanding of neutrino masses. In the final part, the status of current 0νββ experiments is presented and the prospects for the future hunt for 0νββ are discussed. Also, experimental data coming from cosmological surveys are considered and their impact on 0νββ expectations is examined.

  5. Double beta decay and neutrino mass models

    Helo, J C; Ota, T; Santos, F A Pereira dos

    2015-01-01

    Neutrinoless double beta decay allows to constrain lepton number violating extensions of the standard model. If neutrinos are Majorana particles, the mass mechanism will always contribute to the decay rate, however, it is not a priori guaranteed to be the dominant contribution in all models. Here, we discuss whether the mass mechanism dominates or not from the theory point of view. We classify all possible (scalar-mediated) short-range contributions to the decay rate according to the loop level, at which the corresponding models will generate Majorana neutrino masses, and discuss the expected relative size of the different contributions to the decay rate in each class. We also work out the phenomenology of one concrete 2-loop model in which both, mass mechanism and short-range diagram, might lead to competitive contributions, in some detail.

  6. Neutrinoless Double Beta Decay with SNO+

    Hartnell, J

    2012-01-01

    SNO+ will search for neutrinoless double beta decay by loading 780 tonnes of linear alkylbenzene liquid scintillator with O(tonne) of neodymium. Using natural Nd at 0.1% loading will provide 43.7 kg of 150Nd given its 5.6% abundance and allow the experiment to reach a sensitivity to the effective neutrino mass of 100-200 meV at 90% C.L in a 3 year run. The SNO+ detector has ultra low backgrounds with 7000 tonnes of water shielding and self-shielding of the scintillator. Distillation and several other purification techniques will be used with the aim of achieving Borexino levels of backgrounds. The experiment is fully funded and data taking with light-water will commence in 2012 with scintillator data following in 2013.

  7. Weak decays and double beta decay

    Work to measure the Σ+ 0 degree differential cross section in the reaction K-p → Σ+π- at several incident K- momenta between 600 and 800 MeV/c as well as the asymmetries in the decays of polarized Σ+'s into protons and neutral pions and of polarized Σ-'s into neutrons and negative pions in collaboration with experimenters from Yale, Brookhaven, and the University of Pittsburgh (Brookhaven experiment 702) has been completed. Data from this experiment is currently being analyzed at Yale. Work is currently underway to develop and construct an experiment to search for neutrinoless double beta decay in thin foils of Mo100 in collaboration with experimenters from Lawrence Berkeley Laboratory. Development work on the solid state silicon detectors should be complete in the next six months and construction should e well underway within the next year

  8. Semiconductor detectors and double beta decay

    Theoretical physicists have devoted great effort to developing an adequate theory for linking the weak, electromagnetic, and strong forces of nature. Recent theoretical studies and observations of the stability of galaxies have strongly indicated the presence of large amounts of invisible mass. One element in the uncertainty associated with missing mass is the question of whether the neutrino has rest mass. A better understanding of the neutrino, explored in this paper by the possibility of double beta decay in the germanium 76 isotope, could perhaps provide some answers. Nuclear transitions are only energetically possible where the final nucleus is more tightly bound than its parent. The decay of germanium 76 to arsenic 76 is not energetically possible because the arsenic isotope is about 0.9 MeV less tightly bound than the germanium. The selenium 76 isotope, on the other hand, is about 2 MeV more tightly bound; therefore, a transition involving emission of two electrons by a germanium 76 nucleus to form a selenium 76 nucleus is energetically possible. The total energy release in kinetic energy of the beta particles and corresponding neutrinos from the excited daughter product is determined by the energy difference. This energetically possible event, if observed, will provide a breakthrough in understanding the universe. This paper discusses the underlying theory and a germanium detector experiment which could make such a contribution to the resolution of this question

  9. New exotics in the double beta decay contributions zoo

    Klapdor-Kleingrothaus, H. V.; Päs, H.; Sarkar, U.

    2000-01-01

    We discuss the potential of neutrinoless double beta decay for testing Lorentz invariance and the weak equivalence principle as well as contributions from dilaton exchange gravity in the neutrino sector. While neutrino oscillation bounds constrain the region of large mixing of the weak and gravitational eigenstates, we obtain new constraints on violations of Lorentz invariance and the equivalence principle from neutrinoless double beta decay, applying even in the case of no mixing. Double bet...

  10. Neutrinoless double beta decay in Gerda

    Grabmayr, Peter; Gerda Collaboration

    2015-10-01

    The Germanium Detector Array (Gerda) experiment searches for the neutrinoless double beta decay in 76Ge. This lepton number violating process is predicted by extensions of the standard model. Gerda follows a staged approach by increasing mass and lowering the background level from phase to phase. Gerda is setup at the Gran Sasso underground laboratory of INFN, Italy. An array of high-purity germanium detectors is lowered directly in liquid argon for shielding and cooling. Further background reduction is achieved by an instrumented water buffer. In Phase I an exposure of 21.6 kg yr was collected at a background level of 10-2 cts/(keV kg yr). The lower limit on the half-life of 76Ge > 2 . 1 .1025 yr (90% C.L.) has been published. Further analyses search for decay into excited states or the accompanied Majoron decay. Presently, Phase II is in preparation which intends to reach a background level of 10-3 cts/(keV kg yr) and to increase the exposure to 100 kg yr. About 20 kg of novel thick-window BEGe (Broad Energy Germanium) detectors will be added and the liquid argon will be instrumented. The status of Phase II preparation and results from the commissioning runs will be presented as well as some further results from Phase I.

  11. New particle searches by double beta decay

    So far, neutrinoless double beta decay has not been observed, but the lifetime limit (3-10/sup 23/ years) is such a stringent one that its non-observation can set the best upper limit for the mass of the electron neutrino (if it is a Majorana particle) and the best lower limit on the mass of a heavy Majorana neutrino for a given coupling to the electron neutrino, ν/sub e/. In addition it provides the best limit on the coupling of light bosons, such as Majorons, to ν/sub e/, and also the best limit on the existence of right-handed currents in the case in which all right-handed Majorana neutrinos are heavier than all left-handed leptons. The apparatus has to have such low backgrounds even in the keV energy region that it also can be used to set the best terrestrial limits on the mass of solar axions and of other dark matter candidates

  12. Scalar-mediated double beta decay and LHC

    Gonzales, L; Hirsch, M; Kovalenko, S G

    2016-01-01

    The decay rate of neutrinoless double beta decay could be dominated by short-range diagrams involving heavy scalar particles ("topology-II" diagrams). Examples are diagrams with diquarks, leptoquarks or charged scalars. Here, we compare the discovery potential for lepton number violating signals at the LHC with constraints from dijet and leptoquark searches and the sensitivity of double beta decay experiments, using three example models. We note that already with 20/fb the LHC will test interesting parts of the parameter space of these models, not excluded by current limits on double beta decay.

  13. Double beta decay with large scale Yb-loaded scintillators

    Zuber, K.

    2000-01-01

    The potential of large scale Yb-loaded liquid scintillators as proposed for solar neutrino spectroscopy are investigated with respect to double beta decay. The potential for beta-beta- - decay of 176Yb as well as the beta+/EC - decay for 168Yb is discussed. Not only getting for the first time an experimental half-life limit on 176Yb - decay, this will even be at least comparable or better than existing ones from other isotopes. Also for the first time a realistic chance to detect beta+/EC - d...

  14. Neutrino Mass Ordering in Future Neutrinoless Double Beta Decay Experiments

    Zhang, Jue

    2016-01-01

    Motivated by recent intensive experimental efforts on searching for neutrinoless double beta decays, we present a detailed quantitative analysis on the prospect of resolving neutrino mass ordering in the next generation $^{76}$Ge-type experiments.

  15. Neutrinoless double beta decay, solar neutrinos and mass scales

    Osland, Per; Vigdel, Geir

    2001-01-01

    We obtain bounds for the neutrino masses by combining atmospheric and solar neutrino data with the phenomenology of neutrinoless double beta decay where hypothetical values of || are envisaged from future 0\

  16. NEXT, a HPGXe TPC for neutrinoless double beta decay searches

    Granena, F; Nova, F; Rico, J; Sánchez, F; Nygren, D R; Barata, J A S; Borges, F I G M; Conde, C A N; Dias, T H V T; Fernandes, L M P; Freitas, E D C; Lopes, J A M; Monteiro, C M B; Santos, J M F dos; Santos, F P; Tavora, L M N; Veloso, J F C A; Calvo, E; Gil-Botella, I; Novella, P; Palomares, C; Verdugo, A; Giomataris, Yu; Ferrer-Ribas, E; Hernando-Morata, J A; Martínez, D; Cid, X; Ball, M; Carcel, S; Cervera-Villanueva, Anselmo; Díaz, J; Gil, A; Gómez-Cadenas, J J; Martín-Albo, J; Monrabal, F; Munoz-Vidal, J; Serra, L; Sorel, M; Yahlali, N; Bosch, R Esteve; Lerche, C W; Martinez, J D; Mora, F J; Sebastiá, A; Tarazona, A; Toledo, J F; Lazaro, M; Perez, J L; Ripoll, L; Carmona, J M; Cebrián, S; Dafni, T; Galan, J; Gomez, H; Iguaz, F J; Irastorza, I G; Luzón, G; Morales, J; Rodríguez, A; Ruz, J; Tomas, A; Villar, J A

    2009-01-01

    We propose a novel detection concept for neutrinoless double-beta decay searches. This concept is based on a Time Projection Chamber (TPC) filled with high-pressure gaseous xenon, and with separated-function capabilities for calorimetry and tracking. Thanks to its excellent energy resolution, together with its powerful background rejection provided by the distinct double-beta decay topological signature, the design discussed in this Letter Of Intent promises to be competitive and possibly out-perform existing proposals for next-generation neutrinoless double-beta decay experiments. We discuss the detection principles, design specifications, physics potential and R&D plans to construct a detector with 100 kg fiducial mass in the double-beta decay emitting isotope Xe(136), to be installed in the Canfranc Underground Laboratory.

  17. Double beta decay experiments: beginning of a new era

    Barabash, A S

    2012-01-01

    The review of current experiments on search and studying of double beta decay processes is done. Results of the most sensitive experiments are discussed and values of modern limits on effective Majorana neutrino mass ($) are given. New results on two neutrino double beta decay are presented. The special attention is given to new current experiments with mass of studied isotopes more than 100 kg, EXO--200 and KamLAND--Zen. These experiments open a new era in research of double beta decay. In the second part of the review prospects of search for neutrinoless double beta decay in new experiments with sensitivity to $$ at the level of $\\sim 0.01-0.1$ eV are discussed. Parameters and characteristics of the most perspective projects (CUORE, GERDA, MAJORANA, SuperNEMO, EXO, KamLAND--Zen, SNO+) are given.

  18. Status and Perspectives of Double Beta Decay Searches

    Zuber, K.

    2015-11-01

    Double beta decay is an extremely rare process and requires half-life measurements around 1020 years for the neutrino accompanied and well beyond that for the neutrinoless mode. The current status of the search will be discussed.

  19. Neutrinoless double beta decay and lepton number violating new physics

    Neutrinoless double beta decay is a very promising experimental test for lepton number violation. The exchange of light Majorana neutrinos is the simplest realization of this decay, but other physics beyond the Standard Model may also mediate neutrinoless double beta decay. We discuss the interplay of different mechanisms and the influence such an interplay has on the extraction of parameters of the neutrino sector from experimental results.

  20. Possible background reductions in double beta decay experiments

    Arnold, R; Baker, J; Barabash, A S; Bing, O; Brudanin, V B; Caffrey, A J; Caurier, E; Errahmane, K; Etienvre, A I; Guyonnet, J L; Hubert, F; Hubert, P; Jollet, C; Jullian, S; Kochetov, O I; Kovalenko, V; Lalanne, D; Leccia, F; Longuemare, C; Marquet, C; Mauger, F; Nicholson, H W; Ohsumi, H; Piquemal, F; Reyss, J L; Sarazin, X; Shitov, Yu P; Simard, L C; Stekl, I; Suhonen, J; Sutton, C S; Szklarz, G; Timkin, V; Tretyak, V I; Umatov, V I; Vàla, L; Vanyushin, I A; Vasilyev, V; Vorobel, V; Vylov, T D; Hubert, Ph.; Marquet, Ch.; Shitov, Yu.; Vylov, Ts.

    2003-01-01

    The background induced by radioactive impurities of $^{208}\\rm Tl$ and $^{214}\\rm Bi$ in the source of the double beta experiment NEMO-3 has been investigated. New methods of data analysis which decrease the background from the above mentioned contamination are identified. The techniques can also be applied to other double beta decay experiments capable of measuring independently the energies of the two electrons.

  1. Background capabilities of pixel detectors for double beta decay measurements

    Cermak, Pavel, E-mail: pavel.cermak@utef.cvut.cz [Institute of Experimental and Applied Physics, CTU in Prague, 12800 Prague (Czech Republic); Stekl, Ivan; Bocarov, Viktor; Jose, Joshy M.; Jakubek, Jan; Pospisil, Stanislav [Institute of Experimental and Applied Physics, CTU in Prague, 12800 Prague (Czech Republic); Fiederle, Michael; Fauler, Alex [Freiburger Materialforschungszentrum, Albert-Ludwigs-Universitaet Freiburg, D-79104 Freiburg (Germany); Zuber, Kai [Institut fuer Kern- und Teilchenphysik, Technische Universitaet Dresden, 01069 Dresden (Germany); Loaiza, Pia [Laboratoire Souterrain de Modane, 73500 Modane (France); Shitov, Yuriy [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation)

    2011-05-15

    We discuss the possible use of a progressive detection technique based on pixel detectors for the study of double beta decay ({beta}{beta}) processes. A series of background measurements in various environments (surface laboratory, underground laboratory, with and without Pb shielding) was performed using the TimePix silicon hybrid pixel device. The pixel detector response to the natural background and intrinsic background properties measured by a low-background HPGe detector are presented.

  2. Search for neutrinoless double beta decay with DCBA

    A project called DCBA (Drift Chamber Beta-ray Analyzer) is in progress at KEK in order to search for the events of neutrinoless double beta decay. For investigating technical problems, a test apparatus called DCBA-T has been constructed. The preliminary results of its engineering run are described together with the simulation studies of backgrounds originating from 214Bi and 208Tl

  3. Systematic study of double beta decay to excited final states

    A systematic study of two-neutrino double beta (2νββ) decay to the final ground state and excited states is performed within a microscopic quasiparticle random phase approximation (QRPA) model. The excited states are assumed to have the structure of one or two QRPA phonons. This study of the 2νββ decay rates is complemented with the study of single-beta-decay feeding of the relevant nuclei taking part in the double beta process. The Woods-Saxon single-particle energies have been corrected near the Fermi surface by comparing the BCS quasi-particle energies with spectroscopic data of the relevant odd-mass nuclei. Pairing gaps, energy systematics of the Gamow-Teller-States and the available beta-decay data have been used to obtain effective, model-space adapted, two-body matrix elements starting from the G-matrix elements of the Bonn one-boson-exchange potential. This enables a parameter-free calculation of the double Gamow-Teller matrix elements and theoretical prediction of double-beta half lives. The harmonic two-phonon approximation has been used in the beta-decay analysis and the subsequent 2νββ calculations. (authors)

  4. Complementarity of Neutrinoless Double Beta Decay and Cosmology

    Dodelson, Scott; Lykken, Joseph

    2014-03-20

    Neutrinoless double beta decay experiments constrain one combination of neutrino parameters, while cosmic surveys constrain another. This complementarity opens up an exciting range of possibilities. If neutrinos are Majorana particles, and the neutrino masses follow an inverted hierarchy, then the upcoming sets of both experiments will detect signals. The combined constraints will pin down not only the neutrino masses but also constrain one of the Majorana phases. If the hierarchy is normal, then a beta decay detection with the upcoming generation of experiments is unlikely, but cosmic surveys could constrain the sum of the masses to be relatively heavy, thereby producing a lower bound for the neutrinoless double beta decay rate, and therefore an argument for a next generation beta decay experiment. In this case as well, a combination of the phases will be constrained.

  5. Status and perspectives of double beta decay searches

    Double beta decay is a very rare nuclear decay characterised by a change of 2 units the ordering number Z while leaving the mass number A constant. It can basically occur in two modes, with the emission of two electrons and two anti-neutrinos or the emission of two electrons only. The neutrinoless double beta decay of nuclei is not allowed in the Standard Model and is of outstanding importance for neutrino physics. It can only occur if a neutrino is its own antiparticle and if it has a non-vanishing rest mass. After a general introduction into double beta decay, the talk focusses on the current experimental searches and results and their implications for particle physics. An outlook towards future projects and the involved challenges is given. This includes a discussion on nuclear matrix elements and possible supporting experimental activities.

  6. The Enriched Xenon Observatory (EXO) for double beta decay

    The Enriched Xenon Observatory (EXO) is an experimental program designed to search for the neutrinoless double beta decay (0νββ) of Xe-136. of 0nbb would determine an absolute mass scale for neutrinos and answer the question about their Majorana nature. The current phase of the experiment, EXO-200, uses 200 kg of liquid xenon with 80% enrichment in Xe-136. The double beta decay of xenon is detected in an ultra-low background time projection chamber by collecting both, the scintillation light and the ionization charge. The detector has provided the first measurement of two neutrino double beta decay and continues to take data for a neutrinoless analysis.

  7. Sensitivity of NEXT-100 to neutrinoless double beta decay

    Martín-Albo, J; Ferrario, P.; Nebot-Guinot, M.; Gomez-Cadenas, J.J.; Alvarez, V.; Azevedo, C.D.R.; Borges, F.I.G.; Carcel, S.; Cebrian, S.; Cervera, A.; Conde, C.A.N.; Diaz, J.; Diesburg, M.; Esteve, R.; Fernandes, L.M.P.; Ferreira, A.L.; Freitas, E.D.C.; Gehman, V.M.; Goldschmidt, A.; Gonzalez-Diaz, D.; Gutierrez, R.M.; Hauptman, J.; Henriques, C.A.O.; Hernando Morata, J.A.; Labarga, L.; Laing, A.; Lebrun, P.; Liubarsky, I.; Lopez-March, N.; Lorca, D.; Losada, M.; Mari, A.; Martinez-Lema, G.; Martinez, A.; Miller, T.; Monrabal, F.; Monserrate, M.; Monteiro, C.M.B.; Mora, F.J.; Moutinho, L.M.; Novella, P.; Nygren, D.; Para, A.; Perez, J.; Perez Aparicio, J.L.; Querol, M.; Renner, J.; Ripoll, L.; Rodriguez, J.; Santos, F.P.; dos Santos, J.M.F.; Serra, L.; Shuman, D.; Simon, A.; Sofka, C.; Sorel, M.; Stiegler, T.; Toledo, J.F.; Torrent, J.; Tsamalaidze, Z.; Veloso, J.F.C.A.; Villar, J.A.; Webb, R.; White, J.T.; Yahlali, N.; Yepes-Ramirez, H.

    2016-01-01

    NEXT-100 is an electroluminescent high-pressure xenon gas time projection chamber that will search for the neutrinoless double beta decay of Xe-136. The detector possesses two features of great value in neutrinoless double beta decay searches: very good energy resolution (better than 1% FWHM at the Q value of Xe-136) and track reconstruction for the discrimination of signal and background events. This combination results in excellent sensitivity, as discussed in this paper. Detailed Monte Carlo detector simulations and material-screening measurements predict a background rate for NEXT-100 of at most 0.0004 counts/(keV kg yr). Accordingly, the detector will reach a sensitivity to the neutrinoless double beta decay half-life of 6.E25 years after running for 3 effective years.

  8. Neutrinoless Double Beta Decay and High-Scale Baryogenesis

    Graf, Lukas; Huang, Wei-Chih

    2015-01-01

    The constraints on baryogenesis models obtained from an observation of neutrinoless double beta decay are discussed. The lepton number violating processes, which can underlie neutrinoless double beta decay, would together with sphaleron processes, which are effective in a wide range of energies, wash out any primordial baryon asymmetry of the universe. Typically, if a mechanism of neutrinoless double beta decay other than the standard light neutrino exchange is observed, typical scenarios of high-scale baryogenesis will be excluded. This can be achieved by different methods, e.g. through the observation in multiple isotopes or the measurement of the decay distribution. In addition, we will also highlight the connection with low energy lepton flavour violation and lepton number violation at the LHC.

  9. Short-range correlations and neutrinoless double beta decay

    Kortelainen, M; Suhonen, J; Toivanen, J

    2007-01-01

    In this work we report on the effects of short-range correlations upon the matrix elements of neutrinoless double beta decay. We focus on the calculation of the matrix elements of the neutrino-mass mode of neutrinoless double beta decays of 48Ca and 76Ge. The nuclear-structure components of the calculation, that is the participant nuclear wave functions, have been calculated in the shell-model scheme for 48Ca and in the proton-neutron quasiparticle random-phase approximation (pnQRPA) scheme for 76Ge. We compare the traditional approach of using the Jastrow correlation function with the more complete scheme of the unitary correlation operator method (UCOM). Our results indicate that the Jastrow method vastly exaggerates the effects of short-range correlations on the neutrinoless double beta decay nuclear matrix elements.

  10. Q value of the 100Mo Double-Beta Decay

    Rahaman, S; Eronen, T; Hakala, J; Jokinen, A; Julin, J; Kankainen, A; Saastamoinen, A; Suhonen, J; Weber, C; Äystö, J

    2007-01-01

    Penning trap measurements using mixed beams of 100Mo - 100Ru and 76Ge - 76Se have been utilized to determine the double-beta decay Q-values of 100Mo and 76Ge with uncertainties less than 200 eV. The value for 76Ge, 2039.04(16) keV is in agreement with the published SMILETRAP value. The new value for 100Mo, 3034.40(17) keV is 30 times more precise than the previous literature value, sufficient for the ongoing neutrinoless double-beta decay searches in 100Mo. Moreover, the precise Q-value is used to calculate the phase-space integrals and the experimental nuclear matrix element of double-beta decay.

  11. A search for double beta decay of 136Xe

    An experiment on double beta decay of 136Xe has been performed at the Gran Sasso Underground Laboratory (L.N.G.S.). From 6210 h of run with xenon enriched to 64% in 136Xe a 90% C.L. lower limit was derived for neutrinoless double beta decay of 2.0x1022y and 6.5x1021y, for the 0+→0+ and 0+→2+ transitions, respectively. From a comparison between enriched xenon and cleaned xenon a lower limit for the two neutrinos double beta decay of 1.4x1020y at 90% C.L. is also obtained (author) 7 refs., 1 fig., 1 tab

  12. Sensitivity of CUORE to Neutrinoless Double-Beta Decay

    Alessandria, F; Ardito, R; Arnaboldi, C; Avignone, F T; Balata, M; Bandac, I; Banks, T I; Bari, G; Beeman, J; Bellini, F; Bersani, A; Biassoni, M; Bloxham, T; Brofferio, C; Bryant, A; Bucci, C; Cai, X Z; Canonica, L; Capelli, S; Carbone, L; Cardani, L; Carrettoni, M; Casali, N; Chott, N; Clemenza, M; Cosmelli, C; Cremonesi, O; Creswick, R J; Dafinei, I; Dally, A; De Biasi, A; Decowski, M P; Deninno, M M; de Waard, A; Di Domizio, S; Ejzak, L; Faccini, R; Fang, D Q; Farach, H A; Ferri, E; Ferroni, F; Fiorini, E; Foggetta, L; Franceschi, M A; Freedman, S J; Frossati, G; Fujikawa, B; Giachero, A; Gironi, L; Giuliani, A; Goett, J; Gorla, P; Gotti, C; Guardincerri, E; Gutierrez, T D; Haller, E E; Han, K; Heeger, K M; Huang, H Z; Ichimura, K; Kadel, R; Kazkaz, K; Keppel, G; Kogler, L; Kolomensky, Yu G; Kraft, S; Lenz, D; Li, Y L; Liu, X; Longo, E; Ma, Y G; Maiano, C; Maier, G; Maino, M; Mancini, C; Martinez, C; Martinez, M; Maruyama, R H; Moggi, N; Morganti, S; Napolitano, T; Newman, S; Nisi, S; Nones, C; Norman, E B; Nucciotti, A; Orio, F; Orlandi, D; Ouellet, J; Pallavicini, M; Palmieri, V; Pattavina, L; Pavan, M; Pedretti, M; Pessina, G; Pirro, S; Previtali, E; Rampazzo, V; Rimondi, F; Rosenfeld, C; Rusconi, C; Salvioni, C; Sangiorgio, S; Schaeffer, D; Scielzo, N D; Sisti, M; Smith, A R; Stivanello, F; Taffarello, L; Terenziani, G; Tian, W D; Tomei, C; Trentalange, S; Ventura, G; Vignati, M; Wang, B; Wang, H W; Whitten, C A; Wise, T; Woodcraft, A; Xu, N; Zanotti, L; Zarra, C; Zhu, B X; Zucchelli, S

    2011-01-01

    We study the sensitivity of CUORE, a bolometric double-beta decay experiment under construction at the Laboratori Nazionali del Gran Sasso in Italy. Two approaches to the computation of experimental sensitivity are discussed and compared, and the formulas and parameters used in the estimation of the sensitivity are provided. Assuming a background rate of 10^-2 cts/(keV kg y), we find that, after 5 years of live time, CUORE has a 1 sigma sensitivity to the neutrinoless double-beta decay half-life of T_1/2 = 1.6 \\times 10^26 y and thus a potential to probe the effective Majorana neutrino mass down to 41-95 meV. This range is compared with the claim of observation of neutrinoless double-beta decay in 76Ge and the preferred range of the neutrino mass parameter space from oscillation results.

  13. Status and perspectives of double beta decay searches

    Zuber, Kai [Inst. fuer Kern- und Teilchenphysik, TU Dresden (Germany)

    2011-07-01

    Double beta decay is a very rare nuclear decay characterised by a change of 2 units the ordering number Z while leaving the mass number A constant. It can basically occur in two modes, with the emission of two electrons and two anti-neutrinos or the emission of two electrons only. The neutrinoless double beta decay of nuclei is not allowed in the Standard Model and is of outstanding importance for neutrino physics. It can only occur if a neutrino is its own antiparticle and if it has a non-vanishing rest mass. After a general introduction into double beta decay, the talk focusses on the current experimental searches and results and their implications for particle physics. An outlook towards future projects and the involved challenges is given. This includes a discussion on nuclear matrix elements and possible supporting experimental activities.

  14. Measurement of the ββ decay half-life of 130Te with the NEMO-3 detector.

    Arnold, R; Augier, C; Baker, J; Barabash, A S; Basharina-Freshville, A; Blondel, S; Bongrand, M; Broudin-Bay, G; Brudanin, V; Caffrey, A J; Chapon, A; Chauveau, E; Durand, D; Egorov, V; Flack, R; Garrido, X; Grozier, J; Guillon, B; Hubert, Ph; Hugon, C; Jackson, C M; Jullian, S; Kauer, M; Klimenko, A; Kochetov, O; Konovalov, S I; Kovalenko, V; Lalanne, D; Lamhamdi, T; Lang, K; Liptak, Z; Lutter, G; Mamedov, F; Marquet, Ch; Martin-Albo, J; Mauger, F; Mott, J; Nachab, A; Nemchenok, I; Nguyen, C H; Nova, F; Novella, P; Ohsumi, H; Pahlka, R B; Perrot, F; Piquemal, F; Reyss, J L; Richards, B; Ricol, J S; Saakyan, R; Sarazin, X; Simard, L; Simkovic, F; Shitov, Yu; Smolnikov, A; Söldner-Rembold, S; Stekl, I; Suhonen, J; Sutton, C S; Szklarz, G; Thomas, J; Timkin, V; Torre, S; Tretyak, V I; Umatov, V; Vála, L; Vanyushin, I; Vasiliev, V; Vorobel, V; Vylov, Ts; Zukauskas, A

    2011-08-01

    We report results from the NEMO-3 experiment based on an exposure of 1275 days with 661 g of (130)Te in the form of enriched and natural tellurium foils. The ββ decay rate of (130)Te is found to be greater than zero with a significance of 7.7 standard deviations and the half-life is measured to be T(½)(2ν) = [7.0 ± 0.9(stat) ± 1.1(syst)] × 10(20) yr. This represents the most precise measurement of this half-life yet published and the first real-time observation of this decay. PMID:21902318

  15. Momentum analyzers DCBA for neutrinoless double beta decay experiments

    Momentum analyzers called Drift Chamber Beta-ray Analyzer (DCBA) are being developed at KEK in order to search for neutrinoless double beta decays of nuclei. A test prototype, DCBA-T2, has been constructed to confirm the principle detecting electron tracks in a uniform magnetic field. Another prototype, DCBA-T3, is now under construction to improve the energy resolution. The test results and the present statuses of these prototypes are presented.

  16. Momentum analyzers DCBA for neutrinoless double beta decay experiments

    Ishihara, Nobuhiro, E-mail: nobuhiro.ishihara@kek.j [High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan)

    2010-11-01

    Momentum analyzers called Drift Chamber Beta-ray Analyzer (DCBA) are being developed at KEK in order to search for neutrinoless double beta decays of nuclei. A test prototype, DCBA-T2, has been constructed to confirm the principle detecting electron tracks in a uniform magnetic field. Another prototype, DCBA-T3, is now under construction to improve the energy resolution. The test results and the present statuses of these prototypes are presented.

  17. Status of the COBRA double beta decay experiment

    Zuber, Kai, E-mail: zuber@physik.tu-dresden.d [Inst. fuer Kern- und Teilchenphysik, Technische Universitaet Dresden, 01069 Dresden (Germany)

    2010-01-01

    The current status of the COBRA experiment is described. Results on the 4-fold forbidden beta decay of {sup 113}Cd and a variety of double beta decay limits of Cd, Zn and Te isotopes are presented based on 18 kg x days of exposure with an array of sixteen CdZnTe semiconductor detectors. A short description on the activities with pixelated detectors for tracking is given.

  18. Status of the COBRA double beta decay experiment

    The current status of the COBRA experiment is described. Results on the 4-fold forbidden beta decay of 113Cd and a variety of double beta decay limits of Cd, Zn and Te isotopes are presented based on 18 kg x days of exposure with an array of sixteen CdZnTe semiconductor detectors. A short description on the activities with pixelated detectors for tracking is given.

  19. Lepton number violating new physics and neutrinoless double beta decay

    Neutrinoless double beta decay is a very sensitive experimental probe for lepton number violating (ΔL=2) physics beyond the Standard Model. Whatever the new physics mechanism is that triggers the decay, according to the well known Schechter-Valle (or Black Box) theorem, it will induce a Majorana mass term for neutrinos. Neutrinoless double beta decay is therefore the only known possibility to ascertain in the foreseeable future whether the neutrino is a Dirac or a Majorana particle. We discuss the relation between various lepton number violating operators, Majorana neutrino masses, and future experiments.

  20. Empirical formula for two neutrino double beta decay

    The double beta (2β) decay is a rare nuclear weak process in which two neutrons in the nucleus are converted into two protons, and two electrons and two electron antineutrinos are emitted. The process can be thought as a sum of 2β decays. For the double beta decay to be possible, the final nucleus must have a larger binding energy than the original nucleus. The present work aims to develop an empirical formula for computing two neutrino 2β decay half-lives

  1. Results on neutrinoless double beta decay from GERDA phase I

    CERN. Geneva

    2013-01-01

    After motivating searches of double beta decay and lepton number violation details about the construction, operation and analysis of GERDA will be given. Results of the recently completed phase I of data taking will then be presented and interpreted. Finally an outlook on future plans will be given.

  2. Computer code for double beta decay QRPA based calculations

    The computer code developed by our group some years ago for the evaluation of nuclear matrix elements, within the QRPA and PQRPA nuclear structure models, involved in neutrino-nucleus reactions, muon capture and β± processes, is extended to include also the nuclear double beta decay

  3. MeV neutrinos in double beta decay

    Zuber, K.

    1996-01-01

    The effect of Majorana neutrinos in the MeV mass range on the double beta decay of various isotopes is studied on pure phenomenological arguments. By using only experimental half life data, limits on the mixing parameter $U_{eh}^2$ of the order 10$^{-7}$ can be derived. Also the possible achievements of upcoming experiments and some consequences are outlined.

  4. Status and perspectives of double beta decay searches

    Double beta decay is an extremely rare process and requires half-live measurements around 1020 years for the neutrino accompanied mode, while for the neutrino-less mode much longer half-lives have to be explored. The various experimental approaches, currently considered for the search of this process, results will be presented

  5. Measurement of double beta decay - experiments TGV and NEMO

    TGV and NEMO, two international collaboration projects are described. The TGV project deals with the double beta decay of 48Ca. In 1998, this project was augmented with the examination of the double beta decay of 106Cd - the β+β+, β+/EC, and EC/EC modes. The main objective of this experiment consists in recording the 2νEC/EC mode (0+ → 0+, ground state), giving rise to the emission of 2 gamma quanta of roughly 21 keV. The NEMO project deals with 100Mo. The main objective of the NEMO-3 experiment consists in the measurement of the half-life of the neutrinoless double decay of this nuclide (about 1025 years)

  6. Status and prospects of searches for neutrinoless double beta decay

    Schwingenheuer, Bernhard

    2012-01-01

    The simultaneous beta decay of two neutrons in a nucleus without the emission of neutrinos (called neutrinoless double beta decay) is a lepton number violating process which is not allowed in the Standard Model of particle physics. More than a dozen experiments using different candidate isotopes and a variety of detection techniques are searching for this decay. Some (EXO-200, Kamland-Zen, GERDA) started to take data recently. EXO and Kamland-Zen have reported first limits of the half life $T_{1/2}^{0\

  7. Three-dimensional drift chambers of the DCBA experiment for neutrinoless double beta decay search

    Ishikawa, T., E-mail: ishikawat@hakone.phys.metro-u.ac.j [Tokyo Metropolitan University, Hachioji, Tokyo 192-0398 (Japan); Igarashi, H.; Sumiyoshi, T. [Tokyo Metropolitan University, Hachioji, Tokyo 192-0398 (Japan); Ishihara, N.; Iwai, G.; Iwase, H.; Kato, Y.; Kawai, M.; Kondou, Y.; Haruyama, T.; Inagaki, T.; Makida, Y.; Ohama, T.; Takahashi, K.; Yamada, Y. [High Energy Accel, Research Organization (KEK), Tsukuba, Ibaraki 305-0801 (Japan); Tashiro, E.; Ishizuka, T. [Shizuoka University, Naka, Hamamatsu, Shizuoka 432-8011 (Japan); Kitamura, S. [Nihon Institute of Medical Science, Iruma-gun, Saitama 350-0435 (Japan); Teramoto, Y. [Osaka City University, Sumiyoshi, Osaka 558-8585 (Japan); Nakano, I. [Okayama University, Okayama 700-8530 (Japan)

    2011-02-01

    The aim of the DCBA (Drift Chamber Beta-ray Analyzer) experiment is to search for neutrinoless double beta decay (0{nu}{beta}{beta}). The half-life of 0{nu}{beta}{beta} is expected to give us the information of Majorana nature and the absolute mass scale of neutrinos. A prototype test apparatus DCBA-T2 has the energy resolution of about 150 keV (FWHM) around 1 MeV. In order to check the detector performance, engineering runs detecting double beta decay of {sup 100}Mo started in May 2009 using natural Mo, which contains 9.6% of {sup 100}Mo. Ten candidates of the double beta decay ({beta}{beta}) have been detected so far. It has been found that the background events due to {sup 214}Bi decay are distinguishable from the double beta decays by detecting {alpha}-particles from {sup 214}Po.

  8. GERDA - a new neutrinoless double beta experiment using 76Ge

    Meierhofer, G.; GERDA Collaboration

    2011-09-01

    The search for neutrinoless double beta decay (0νßß) has been a very active field for the last decades. While double beta decay has been observed, 0νßß decay still waits for its experimental proof. The GErmanium Detector Array (GERDA) uses 76Ge, an ideal candidate as it is acting as source and detector simultaneously. Germanium detectors, isotopically enriched in 76Ge are submerged directly into an ultra pure cryo liquid, which serves as coolant and radiation shield. This concept will allow to reduce the background by up to two orders of magnitude with respect to earlier experiments. GERDA has been constructed in hall A of the underground laboratory LNGS of the INFN in Italy. The experiment started recently with a test run.

  9. GERDA - a new neutrinoless double beta experiment using 76Ge

    The search for neutrinoless double beta decay (0νssss) has been a very active field for the last decades. While double beta decay has been observed, 0νssss decay still waits for its experimental proof. The GErmanium Detector Array (GERDA) uses 76Ge, an ideal candidate as it is acting as source and detector simultaneously. Germanium detectors, isotopically enriched in 76Ge are submerged directly into an ultra pure cryo liquid, which serves as coolant and radiation shield. This concept will allow to reduce the background by up to two orders of magnitude with respect to earlier experiments. GERDA has been constructed in hall A of the underground laboratory LNGS of the INFN in Italy. The experiment started recently with a test run.

  10. Neutrino mass, neutrinoless double electron capture and rare beta decays

    Mustonen, M T; Suhonen, J, E-mail: jouni.suhonen@phys.jyu.f [Department of Physics, PO Box 35 (YFL), FI-40014 University of Jyvaeskylae (Finland)

    2010-01-01

    We present results of our theoretical calculations on three nuclei of interest from the neutrino-physics point of view: Firstly, we present the second-forbidden decay branch of {sup 115}In with the ultra-low Q value and theoretical open questions related to such decays. Secondly, we have calculated estimates for the half-lives of the single-beta decay channels of {sup 96}Zr and concluded that the possible contamination from those to the geochemical measurements of {sup 96}Zr double-beta-decay half-life is rather small. Thirdly, we have taken a look at the neutrinoless resonance double-electron-capture decay of {sup 112}Sn in the light of recent JYFLTRAP Q value measurements and discovered that the badly fulfilled resonance condition renders the decay unobservable.

  11. Neutrinoless double $\\beta$ decay and low scale leptogenesis

    Drewes, Marco

    2016-01-01

    The extension of the Standard Model by right handed neutrinos with masses in the GeV range can simultaneously explain the observed neutrino masses via the seesaw mechanism and the baryon asymmetry of the universe via leptogenesis. It has previously been claimed that the requirement for successful baryogenesis implies that the rate of neutrinoless double $\\beta$ decay in this scenario is always smaller than the standard prediction from light neutrino exchange alone. In contrast, we find that the rate for this process can also be enhanced due to a dominant contribution from heavy neutrino exchange. In a small part of the parameter space it even exceeds the current experimental limit, while the properties of the heavy neutrinos are consistent with all other experimental constraints and the observed baryon asymmetry is reproduced. This implies that neutrinoless double $\\beta$ decay experiments have already started to rule out part of the leptogenesis parameter space that is not constrained by any other experiment...

  12. The Majorana Demonstrator search for neutrinoless double beta decay

    Cuesta, C; Detwiler, J A; Gruszko, J; Guinn, I S; Leon, J; Robertson, R G H; Abgrall, N; Bradley, A W; Chan, Y-D; Mertens, S; Poon, A W P; Vetter, K; Arnquist, I J; Hoppe, E W; Kouzes, R T; Orrell, J L; Avignone, F T; Barabash, A S; Konovalov, S I; Yumatov, V; Bertrand, F E; Galindo-Uribarri, A; Radford, D C; Varner, R L; Yu, C -H; Brudanin, V; Shirchenko, M; Vasilyev, S; Yakushev, E; Zhitnikov, I; Busch, M; Caldwell, T S; Gilliss, T; Henning, R; Howe, M A; MacMullin, J; Meijer, S J; O'Shaughnessy, C; Rager, J; Shanks, B; Trimble, J E; Vorren, K; Xu, W; Christofferson, C D; Dunagan, C; Suriano, A M; Chu, P -H; Elliott, S R; Massarczyk, R; Rielage, K; White, B R; Efremenko, Yu; Lopez, A M; Ejiri, H; Fullmer, A; Giovanetti, G K; Green, M P; Guiseppe, V E; Tedeschi, D; Wiseman, C; Jasinski, B R; Keeter, K J; Kidd, M F; Martin, R D; Romero-Romero, E; Wilkerson, J F

    2016-01-01

    The MAJORANA Collaboration is constructing the MAJORANA DEMONSTRATOR, an ultra-low background, modular, HPGe detector array with a mass of 44.8-kg (29.7 kg enriched >88% in Ge-76) to search for neutrinoless double beta decay in Ge-76. The next generation of tonnescale Ge-based neutrinoless double beta decay searches will probe the neutrino mass scale in the inverted-hierarchy region. The MAJORANA DEMONSTRATOR is envisioned to demonstrate a path forward to achieve a background rate at or below 1 count/tonne/year in the 4 keV region of interest around the Q-value of 2039 keV. The MAJORANA DEMONSTRATOR follows a modular implementation to be easily scalable to the next generation experiment. First data taken with the DEMONSTRATOR are introduced here.

  13. A combined limit for neutrinoless double-beta decay

    Guzowski, Pawel

    2015-01-01

    The search for neutrinoless double-beta decay is important in determining the Majorana nature of the neutrino, and also in establishing if lepton number is violated. In this work, we combine the published data from five independent neutrinoless double-beta decay experiments: CUORICINO, EXO, GERDA, KamLAND-Zen and NEMO-3. As these experiments use different isotope sources, the relative signal normalisation between them depends on the Nuclear Matrix Element (NME) calculations used. The combined limits for the Majorana neutrino mass for 5 different NME models range from 130-310 meV. The combined mass limits can offer an improvement over the individual experiments of up to 25%, depending on the NME model.

  14. Neutrinoless double beta decay search with cuoricino and cuore experiments

    Cuoricino is a bolometric experiment on Neutrinoless Double Beta Decay (ον-DBD) . With its 40.7 kg mass of TeO2 it is the most massive (ον)-DBD presently running and it has proven the feasibility of the CUORE experiment, whose aim is to be sensitive to the effective neutrino mass down to few tens of me V. We report here latest Cuoricino results and prospects for the future CUORE experiment

  15. Perturbative description of nuclear double beta decay transitions

    Bes, D. R.; Civitarese, O.; Scoccola, N.N.

    1998-01-01

    A consistent treatment of intrinsic and collective coordinates is applied to the calculation of matrix elements describing nuclear double beta decay transitions. The method, which was developed for the case of nuclear rotations, is adapted to include isospin and number of particles degrees of freedom. It is shown that the uncertainties found in most models, in dealing with these decay modes, are largely due to the mixing of physical and spurious effects in the treatment of isospin dependent i...

  16. New generation of experiments searching for neutrinoless double beta decay

    Full text: The search for neutrinoless double beta decay is one of the central research topics in fundamental physics. In fact, the observation of neutrinoless double beta decay would not only establish the Majorana nature of the neutrino but also provide a measurement of its effective mass ee> as well as fix the hierarchy of neutrino spectrum. The next generation of experiments aims to probe the effective Majorana neutrino mass down to few 10 MeV, as predicted by oscillation experiments in case of the inverse mass hierarchy. In this talk the most part of the upcoming experiments are reviewed. The sensitivity of the upcoming experiments depend therefore primarily on the available mass of double beta isotopes and the experimental conditions. In particular, the achievable background suppression and the detection efficiency will be decisive for their success. Experimental consideration as detection efficiency and background suppression will determine the final sensitivity of the different experimental approaches. The first of the next generation experiments, such as GERDA at LNGS, Italy, EXO at WIPP, USA and KamLAND-Zen in Japan, became operational recently. New projects like SuperNEMO, MAJORANA, CUORE and others will start in the nearest future. The future development of the field will strongly depend on the results of the upcoming experiments. If neutrinoless double beta decay is observed at the 1 eV scale, as claimed by part of the Heidelberg Moscow experiment, the decay could be studied with high precision with many different isotopes and different techniques. The effective mass could be measured with accuracy and the leading term governing the decay mode identified. In case that the claim is refuted, at least two experiments with about one ton of isotopes and zero background in the region of interest for several year x ton of exposure are required to cover the full mass range down to 10 MeV predicted by oscillation experiments for the inverse mass hierarchy

  17. Nuclear Structure Aspects of Neutrinoless Double Beta Decay

    Brown, B A; Sen'kov, R A

    2014-01-01

    We decompose the neutrinoless double-beta decay matrix elements into sums of products over the intermediate nucleus with two less nucleons. We find that the sum is dominated by the J^pi=0^+ ground state of this intermediate nucleus for both the light and heavy neutrino decay processes. This provides a new theoretical tool for comparing and improving nuclear structure models. It also provides the connection to two-nucleon transfer experiments.

  18. The Effect of Cancellation in Neutrinoless Double Beta Decay

    Pascoli, Silvia; Wong, Steven

    2013-01-01

    In light of recent experimental results, we carefully analyze the effects of interference in neutrinoless double beta decay, when more than one mechanism is operative. We assume a complete cancellation is at work for $^{136}\\rm{Xe}$, and find its implications on the half-life of other isotopes, such as $^{76}\\rm{Ge}$. For definiteness, we consider the role of light and heavy sterile neutrinos. In this case, the effective Majorana mass parameter can be redefined to take into account all contributions and its value gets suppressed. Hence, larger values of neutrino masses are required for the same half-life. The canonical light neutrino contribution can not saturate the present limits of half-lives or the positive claim of observation of neutrinoless double beta decay, once the stringent bounds from cosmology are taken into account. For the case of cancellation, where all the sterile neutrinos are heavy, the tension between the results from neutrinoless double beta decay and cosmology becomes more severe. We sho...

  19. Neutrino masses and Neutrinoless Double Beta Decay: Status and expectations

    Cremonesi, Oliviero

    2010-01-01

    Two most outstanding questions are puzzling the world of neutrino Physics: the possible Majorana nature of neutrinos and their absolute mass scale. Direct neutrino mass measurements and neutrinoless double beta decay (0nuDBD) are the present strategy to solve the puzzle. Neutrinoless double beta decay violates lepton number by two units and can occurr only if neutrinos are massive Majorana particles. A positive observation would therefore necessarily imply a new regime of physics beyond the standard model, providing fundamental information on the nature of the neutrinos and on their absolute mass scale. After the observation of neutrino oscillations and given the present knowledge of neutrino masses and mixing parameters, a possibility to observe 0nuDBDD at a neutrino mass scale in the range 10-50 meV could actually exist. This is a real challenge faced by a number of new proposed projects. Present status and future perpectives of neutrinoless double-beta decay experimental searches is reviewed. The most impo...

  20. Sensitivity of CUORE to Neutrinoless Double-Beta Decay

    CUORE; Alessandria, F.; Andreotti, E.; Ardito, R.; Arnaboldi, C.; Avignone III, F. T.; Balata, M.; Bandac, I.; Banks, T. I.; Bari, G.; Beeman, J.; Bellini, F.; Bersani, A.; Biassoni, M.; Bloxham, T.; Brofferio, C.; Bryant, A.; Bucci, C.; Cai, X. Z.; Canonica, L.; Capelli, S.; Carbone, L.; Cardani, L.; Carrettoni, M.; Casali, N.; Chott, N.; Clemenza, M.; Cosmelli, C.; Cremonesi, O.; Creswick, R. J.; Dafinei, I.; Dally, A.; Biasi, A. De; Decowski, M. P.; Deninno, M. M.; Waard, A. de; Domizio, S. Di; Ejzak, L.; Faccini, R.; Fang, D. Q.; Farach, H. A.; Ferri, E.; Ferroni, F.; Fiorini, E.; Foggetta, L.; Franceschi, M. A.; Freedman, S. J.; Frossati, G.; Fujikawa, B. K.; Giachero, A.; Gironi, L.; Giuliani, A.; Gorla, P.; Gotti, C.; Guardincerri, E.; Gutierrez, T. D.; Haller, E. E.; Han, K.; Heeger, K. M.; Huang, H. Z.; Ichimura, K.; Kadel, R.; Kazkaz, K.; Keppel, G.; Kogler, L.; Kolomensky, Yu. G.; Kraft, S.; Lenz, D.; Li, Y. L.; Liu, X.; Longo, E.; Ma, Y. G.; Maiano, C.; Maier, G.; Maino, M.; Mancini, C.; Martinez, C.; Martinez, M.; Maruyama, R. H.; Moggi, N.; Morganti, S.; Napolitano, T.; Newman, S.; Nisi, S.; Nones, C.; Norman, E. B.; Nucciotti, A.; Orio, F.; Orlandi, D.; Ouellet, J. L.; Pallavicini, M.; Palmieri, V.; Pattavina, L.; Pavan, M.; Pedretti, M.; Pessina, G.; Pirro, S.; Previtali, E.; Rampazzo, V.; Rimondi, F.; Rosenfeld, C.; Rusconi, C.; Salvioni, C.; Sangiorgio, S.; Schaeffer, D.; Scielzo, N. D.; Sisti, M.; Smith, A. R.; Stivanello, F.; Taffarello, L.; Terenziani, G.; Tian, W. D.; Tomei, C.; Trentalange, S.; Ventura, G.; Vignati, M.; Wang, B. S.; Wang, H. W.; Whitten Jr., C. A.; Wise, T.; Woodcraft, A.; Xu, N.; Zanotti, L.; Zarra, C.; Zhu, B. X.; Zucchelli, S.

    2011-11-23

    In this paper, we study the sensitivity of CUORE, a bolometric double-beta decay experiment under construction at the Laboratori Nazionali del Gran Sasso in Italy. Two approaches to the computation of experimental sensitivity are discussed and compared, and the formulas and parameters used in the sensitivity estimates are provided. Assuming a background rate of 10{sup -2} cts/(keV kg y), we find that, after 5 years of live time, CUORE will have a 1 {sigma} sensitivity to the neutrinoless double-beta decay half-life of {caret T{sup 0{nu}}{sub 1/2}}(1{sigma} ) = 1.6x 10{sup 26} y and thus a potential to probe the effective Majorana neutrino mass down to 41-95 meV; the sensitivity at 1.64{sigma} , which corresponds to 90% C.L., will be {caret T{sup 0{nu}}{sub 1/2}(1.64{sigma} }) = 9.5x10{sup 25} y. This range is compared with the claim of observation of neutrinoless double-beta decay in {sup 76}Ge and the preferred range in the neutrino mass parameter space from oscillation results.

  1. CdWO4 bolometers for Double Beta Decay search

    Gironi, L; Capelli, S; Cremonesi, O; Pavan, M; Pessina, G; Pirro, S

    2008-01-01

    In the field of Double Beta Decay (DBD) searches the possibility to have high resolution detectors in which background can be discriminated is very appealing. This very interesting possibility can be largely fulfilled in the case of a scintillating bolometer containing a Double Beta Decay emitter whose transition energy exceeds the one of the natural gamma line of 208Tl. We present the latest results obtained in the development of such a kind of scintillating bolometer. For the first time an array of five CdWO4 (116Cd has a Double Beta Decay transition energy of 2805 keV) crystals is tested. The array consists of a plane of four 3x3x3 cm3 crystals and a second plane consisting of a single 3x3x6 cm3 crystal. This setup is mounted in hall C of the National Laboratory of Gran Sasso inside a lead shielding in order to reduce as far as possible the environmental background. The aim of this test is to demonstrate the technical feasibility of this technique through an array of detectors and perform a long background...

  2. The MAJORANA Neutrinoless Double-Beta Decay Experiment

    Majorana collaboration paper for the IEEE Nuclear Science Symposium held in Dresden, Germany. It includes many authors from 17 institutions. Neutrinoless double-beta decay searches play a major role in determining the nature of neutrinos, the existence of a lepton violating process, and the effective Majorana neutrino mass. The MAJORANA Collaboration proposes to assemble an array of HPGe detectors to search for neutrinoless double-beta decay in 76Ge. Our proposed method uses the well-established technique of searching for neutrinoless double-beta decay in high purity Ge-diode radiation detectors that play both roles of source and detector. The technique is augmented with recent improvements in signal processing and detector design, and advances in controlling intrinsic and external backgrounds. Initially, MAJORANA aims to construct a prototype module containing 60 kg of Ge detectors to demonstrate the potential of a future 1-tonne experiment. The design and potential reach of this prototype Demonstrator module will be presented. This paper will also discuss detector optimization and low-background requirements, such as material purity, background rejection, and identification of rare backgrounds required to reach the sensitivity goals of the MAJORANA experiment.

  3. Study of heavy ions elastic scattering and of friction phenomenon in transfer reactions induced by 28Si on 130Te

    Elastic scattering of heavy-ions 16O and 28Si on 59Co, 109Ag and 130Te have been studied at laboratory incident energies between 80 and 140MeV. The optical model was used to analyse elastic angular distributions and different methods for determining the total reaction cross section have been compared. Transfer reactions induced by 28Si on 130Te have been studied at incident energy superior to the Coulomb barrier in the ratio of 1.27. A study of these reactions shows the transition between the quasi-elastic reactions and deep inelastic reactions coresponding to the phenomenon of friction. The diffusion model is used for the analysis of these results

  4. Neutrino masses from double-beta decay calculations

    Stoica, S

    2002-01-01

    The neutrinoless double-beta decay (0 nu beta beta) matrix elements (ME) for the nuclei with A = 76, 82, 96, 100, 116, 128, 130 and 136 are compared with four different quasi random phase approximation (QRPA) - based method, i.e. the proton-neutron QRPA (pnQRPA), the renormalized proton-neutron QRPA (pnRQRPA), the full RQRPA and the second-QRPA (SQRPA) and using two single-particle basis. From a comparative analysis of the results we show that the uncertainties in the calculation of the ME can be limited to 50% from their values. Further, taking the most recent available limits for the neutrinoless half-lives, we deduce new upper limits for the neutrino mass parameter. Also, there are estimated for each nucleus scales for the (0 nu beta beta) decay half-lives that the experiments should reach for measuring neutrino masses around 0.39 eV. This value was derived from the first experimental evidence of this mode reported very recently by the Heidelberg-Moscow experiment. These estimation give us an indication on...

  5. Effective Majorana mass and neutrinoless double beta decay

    Benato, Giovanni, E-mail: gbenato@physik.uzh.ch [Physik Institut der Universität Zürich, Zurich (Switzerland)

    2015-11-28

    The probability distribution for the effective Majorana mass as a function of the lightest neutrino mass in the standard three neutrino scheme is computed via a random sampling from the distributions of the involved mixing angles and squared mass differences. A flat distribution in the [0,2π] range for the Majorana phases is assumed, and the dependence of small values of the effective mass on the Majorana phases is highlighted. The study is then extended with the addition of the cosmological bound on the sum of the neutrino masses. Finally, the prospects for 0νββ decay search with {sup 76}Ge, {sup 130}Te and {sup 136}Xe are discussed, as well as those for the measurement of the electron neutrino mass.

  6. New limits on double beta processes in 106-Cd

    Tretyak, V I; Bernabei, R; Brudanin, V B; Cappella, F; Caracciolo, V; Cerulli, R; Chernyak, D M; Danevich, F A; d'Angelo, S; Di Marco, A; Incicchitti, A; Laubenstein, M; Mokina, V M; Poda, D V; Polischuk, O G; Tupitsyna, I A

    2016-01-01

    A radiopure cadmium tungstate crystal scintillator, enriched in 106-Cd to 66%, with mass of 216 g (106-CdWO4) was used in coincidence with four ultra-low background HPGe detectors contained in a single cryostat to search for double beta decay processes in 106-Cd. New improved half-life limits on the double beta processes in 106-Cd have been set on the level of 1e20-1e21 yr after 13085 h of data taking deep underground (3600 m w.e.) at the Gran Sasso National Laboratories of INFN (Italy). In particular, the limit on the two neutrino electron capture with positron emission T1/2 >1.1e21 yr, has reached the region of theoretical predictions. The resonant neutrinoless double electron captures to the 2718, 2741 and 2748 keV excited states of 106-Pd are restricted on the level of T1/2 > 8.5e20 - 1.4e21 yr.

  7. Search for beta plus/EC double beta decay of 120Te

    Andreotti, E; Avignone, F T; Balata, M; Bandac, I; Barucci, M; Beeman, J W; Bellini, F; Brofferio, C; Bryant, A; Bucci, C; Canonica, L; Capelli, S; Carbone, L; Carrettoni, M; Clemenza, M; Cremonesi, O; Creswick, R J; Di Domizio, S; Dolinski, M J; Ejzak, L; Faccini, R; Farach, H A; Ferri, E; Fiorini, E; Foggetta, L; Giachero, A; Gironi, L; Giuliani, A; Gorla, P; Guardincerri, E; Haller, T D Gutierrez E E; Kazkaz, K; Kraft, S; Kogler, L; Maiano, C; Maruyama, R H; Martinez, C; Martinez, M; Mizouni, L; Newman, S; Nisi, S; Nones, C; Norman, E B; Nucciotti, A; Orio, F; Pallavicini, M; Palmieri, V; Pattavina, L; Pavan, M; Pedretti, M; Pessina, G; Pirro, S; Previtali, E; Risegari, L; Rosenfeld, C; Rusconi, C; Salvioni, C; Sangiorgio, S; Schaeffer, D; Scielzo, N D; Sisti, M; Smith, A R; Tomei, C; Ventura, G; Vignati, M

    2010-01-01

    We present a search for beta plus/EC double beta decay of 120Te performed with the CUORICINO experiment, an array of TeO2 cryogenic bolometers. After collecting 0.0573 kg y of 120Te, we see no evidence of a signal and therefore set the following limits on the half-life: T1/2 (0nu) > 1.9 10^{21} y at 90% C.L. for the 0 neutrino mode and T1/2 (2nu) > 7.6 10^{19} y at 90% C.L. for the two neutrino mode. These results improve the existing limits by almost three orders of magnitude (four in the case of 0 neutrino mode). Moreover the limit on zero neutrino beta plus/EC represents the most stringent half-life limit ever achieved for this decay mode for any isotope.

  8. Neutrinoless double beta decay and heavy sterile neutrinos

    The experimental rate of neutrinoless double beta decay can be saturated by the exchange of virtual sterile neutrinos, that mix with the ordinary neutrinos and are heavier than 200 MeV. Interestingly, this hypothesis is subject only to marginal experimental constraints, because of the new nuclear matrix elements. This possibility is analyzed in the context of the Type I seesaw model, performing also exploratory investigations of the implications for heavy neutrino mass spectra, rare decays of mesons as well as neutrino-decay search, LHC, and lepton flavor violation. The heavy sterile neutrinos can saturate the rate only when their masses are below some 10 TeV, but in this case, the suppression of the light-neutrino masses has to be more than the ratio of the electroweak scale and the heavy-neutrino scale; i.e., more suppressed than the naive seesaw expectation. We classify the cases when this condition holds true in the minimal version of the seesaw model, showing its compatibility (1) with neutrinoless double beta rate being dominated by heavy neutrinos and (2) with any light neutrino mass spectra. The absence of excessive fine-tunings and the radiative stability of light neutrino mass matrices, together with a saturating sterile neutrino contribution, imply an upper bound on the heavy neutrino masses of about 10 GeV. We extend our analysis to the Extended seesaw scenario, where the light and the heavy sterile neutrino contributions are completely decoupled, allowing the sterile neutrinos to saturate the present experimental bound on neutrinoless double beta decay. In the models analyzed, the rate of this process is not strictly connected with the values of the light neutrino masses, and a fast transition rate is compatible with neutrinos lighter than 100 meV.

  9. The GERDA Neutrinoless Double Beta-Decay Experiment

    Neutrinoless double beta (0νββ)-decay is the key process to gain understanding of the nature of neutrinos. The GErmanium Detector Array (GERDA) is designed to search for 0νββ-decay of the isotope 76Ge. Germanium crystals enriched in 76Ge, acting as source and detector simultaneously, will be submerged directly into an ultra pure cooling medium that also serves as a radiation shield. This concept will allow for a reduction of the background by up to two orders of magnitudes with respect to earlier experiments

  10. Search of Neutrinoless Double Beta Decay with the GERDA Experiment

    Benato, Giovanni

    2015-01-01

    The Gerda experiment designed to search for the neutrinoless double beta decay in 76Ge has successfully completed the first data collection. No signal excess is found, and a lower limit on the half life of the process is set, with T1/2 > 2.1x10^25 yr (90% CL). After a review of the experimental setup and of the main Phase I results, the hardware upgrade for Gerda Phase II is described, and the physics reach of the new data collection is reported.

  11. Neutrinoless Double Beta Decay in Heavy Deformed Nuclei

    Hirsch, Jorge G.; Castaños, O.; Hess, P. O.

    1994-01-01

    The zero neutrino mode of the double beta decay in heavy deformed nuclei is investigated in the framework of the pseudo SU(3) model, which has provided an accurate description of collective nuclear structure and predicted half-lives for the two neutrino mode in good agreement with experiments. In the case of $^{238}U$ the calculated zero neutrino half-life is at least three orders of magnitude greater than the two neutrino one, giving strong support of the identification of the radiochemicall...

  12. EXO the Enriched Xenon Observatory for Double Beta Decay

    Wamba, K

    2002-01-01

    EXO is a search for neutrinoless double beta decay in 136Xe. An active R&D program for a 10 ton, enriched 136Xe liquid phase detector is now underway. Current research projects are: decay product extraction, Xe purity studies, energy resolution studies, and Ba+ ion laser-tagging. By extracting and laser-tagging the Xe decay product (136Ba) and optimizing the energy resolution in liquid Xe, half lives of up to 5.0x10^28yr will be ultimately probed, corresponding to a sensitivity to Majorana n masses > ~10meV.

  13. Values of the phase space factors for double beta decay

    We report an up-date list of the experimentally most interesting phase space factors for double beta decay (DBD). The electron/positron wave functions are obtained by solving the Dirac equations with a Coulomb potential derived from a realistic proton density distribution in nucleus and with inclusion of the finite nuclear size (FNS) and electron screening (ES) effects. We build up new numerical routines which allow us a good control of the accuracy of calculations. We found several notable differences as compared with previous results reported in literature and possible sources of these discrepancies are discussed

  14. Neutrinoless Double Beta Decay and Lepton Flavor Violation

    Cirigliano, V.; Kurylov, A.; Ramsey-Musolf, M. J.; Vogel, P.

    2004-01-01

    We point out that extensions of the standard model with low scale (~TeV) lepton number violation (LNV) generally lead to a pattern of lepton flavor violation (LFV) experimentally distinguishable from the one implied by models with grand unified theory scale LNV. As a consequence, muon LFV processes provide a powerful diagnostic tool to determine whether or not the effective neutrino mass can be deduced from the rate of neutrinoless double beta decay. We discuss the role of µ-->egamma and µ-->...

  15. LUCIFER: A new technique for Double Beta Decay

    Ferroni, Fernando

    2011-01-01

    LUCIFER (Low-background Underground Cryogenic Installation For Elusive Rates) is a new project aiming to study the neutrinoless Double Beta Decay. It will be based on the technology of the scintillating bolometers. These devices shall have a great power in distinguishing signals from α’s and β/γ’s promising a background-free experiment, provided that the Q value of the candidate isotope is higher than the 208Tl line. The baseline candidate for LUCIFER is 82Se. Here the LUCIFER concept will be...

  16. The Majorana Ge-76 Double-Beta Decay Project

    Aalseth, C E; Barabash, A S; Bowyer, T W; Brodzinski, R L; Brudanin, V B; Collar, J I; Doe, P J; Egorov, S; Elliott, S R; Farach, H A; Gaitskell, R J; Jordan, D; Kochetov, O I; Konovalov, S V; Kouzes, R T; Miley, H S; Pitts, W K; Reeves, J H; Robertson, R G H; Sandukovsky, V G; Smith, E; Stekhanov, V; Thompson, R C; Tornow, W; Umatov, V I; Warner, R A; Webb, J; Wilkerson, J F; Young, A

    2002-01-01

    The Majorana Experiment is a next-generation Ge-76 double-beta decay search. It will employ 500 kg of Ge, isotopically enriched to 86% in Ge-76, in the form of 200 detectors in a close-packed array for high granularity. Each crystal will be electronically segmented, with each region fitted with pulse-shape analysis electronics. A half-life sensitivity is predicted of 4.2e27 y or < 0.02-0.07 eV, depending on the nuclear matrix elements used to interpret the data.

  17. Impact of Neutrinoless Double Beta Decay on Models of Baryogenesis

    Deppisch, Frank F; Huang, Wei-Chih

    2015-01-01

    Interactions that manifest themselves as lepton number violating processes at low energies in combination with sphaleron transitions typically erase any pre-existing baryon asymmetry of the Universe. We demonstrate in a model independent approach that the observation of neutrinoless double beta decay would impose a stringent constraint on mechanisms of high-scale baryogenesis, including leptogenesis scenarios. Further, we discuss the potential of the LHC to model independently exclude high-scale leptogenesis scenarios when observing lepton number violating processes. In combination with the observation of lepton flavor violating processes, we can further strengthen this argument, closing the loophole of asymmetries being stored in different lepton flavors.

  18. The background in the neutrinoless double beta decay experiment GERDA

    Agostini, M; Andreotti, E; Bakalyarov, A M; Balata, M; Barabanov, I; Heider, M Barnabe; Barros, N; Baudis, L; Bauer, C; Becerici-Schmidt, N; Bellotti, E; Belogurov, S; Belyaev, S T; Benato, G; Bettini, A; Bezrukov, L; Bode, T; Brudanin, V; Brugnera, R; Budjas, D; Caldwell, A; Cattadori, C; Chernogorov, A; Cossavella, F; Demidova, E V; Domula, A; Egorov, V; Falkenstein, R; Ferella, A; Freund, K; Frodyma, N; Gangapshev, A; Garfagnini, A; Gotti, C; Grabmayr, P; Gurentsov, V; Gusev, K; Guthikonda, K K; Hampel, W; Hegai, A; Heisel, M; Hemmer, S; Heusser, G; Hofmann, W; Hult, M; Inzhechik, L V; Ioannucci, L; Csathy, J Janicsko; Jochum, J; Junker, M; Kihm, T; Kirpichnikov, I V; Kirsch, A; Klimenko, A; Knoepfle, K T; Kochetov, O; Kornoukhov, V N; Kuzminov, V V; Laubenstein, M; Lazzaro, A; Lebedev, V I; Lehnert, B; Liao, H Y; Lindner, M; Lippi, I; Liu, X; Lubashevskiy, A; Lubsandorzhiev, B; Lutter, G; Macolino, C; Machado, A A; Majorovits, B; Maneschg, W; Nemchenok, I; Nisi, S; O'Shaughnessy, C; Palioselitis, D; Pandola, L; Pelczar, K; Pessina, G; Pullia, A; Riboldi, S; Sada, C; Salathe, M; Schmitt, C; Schreiner, J; Schulz, O; Schwingenheuer, B; Schoenert, S; Shevchik, E; Shirchenko, M; Simgen, H; Smolnikov, A; Stanco, L; Strecker, H; Tarka, M; Ur, C A; Vasenko, A A; Volynets, O; von Sturm, K; Wagner, V; Walter, M; Wegmann, A; Wester, T; Wojcik, M; Yanovich, E; Zavarise, P; Zhitnikov, I; Zhukov, S V; Zinatulina, D; Zuber, K; Zuzel, G

    2014-01-01

    The GERmanium Detector Array (GERDA) experiment at the Gran Sasso underground laboratory (LNGS) of INFN is searching for neutrinoless double beta decay of 76Ge. The signature of the signal is a monoenergetic peak at 2039 keV, the Q-value of the decay, Q_bb. To avoid bias in the signal search, the present analysis does not consider all those events, that fall in a 40 keV wide region centered around Q_bb. The main parameters needed for the neutrinoless double beta decay analysis are described. A background model was developed to describe the observed energy spectrum. The model contains several contributions, that are expected on the basis of material screening or that are established by the observation of characteristic structures in the energy spectrum. The model predicts a flat energy spectrum for the blinding window around Q_bb with a background index ranging from 17.6 to 23.8*10^{-3} counts/(keV kg yr). A part of the data not considered before has been used to test if the predictions of the background model...

  19. Present and future strategies for neutrinoless double beta decay searches

    C Brofferio

    2010-08-01

    The renewed interest shown in these days towards neutrinoless double beta decay, a lepton number violating process which can take place only if neutrinos are Majorana particles ($ = \\bar{}$) with a nonvanishing mass, is justified by the fact that the Majorana nature of neutrinos is expected in many theories beyond the Standard Model. We also now know, thanks to the neutrino oscillation experiments, that neutrinos are in fact massive, as expected in these theories and not requested in the Standard Model. Moreover, since neutrino oscillation experiments measure only the absolute value of the difference of the square of the neutrino masses, the discovery of neutrinoless double beta decay would help to disentangle questions that still remain unsolved: what is the absolute mass scale of the neutrinos and which mass hierarchy (normal, inverted or quasi-degenerate) is the correct one? The scope of this paper is not only to review the present results reached in the field by the different groups and technologies worldwide, but also to illustrate and comment on the (near and long-term) future strategies that experimentalists are trying to pursue to reach the needed sensitivity required to explore the inverted hierarchy neutrino mass scale.

  20. Search for neutrinoless double beta decay in 124Sn

    Nanal Vandana

    2014-03-01

    Full Text Available The mass and nature of neutrinos play an important role in theories beyond the standard model. The nuclear β decay and double beta decay can provide the information on absolute effective mass of the neutrinos, which would represent a major advance in our understanding of particle physics. At present, neutrinoless double beta decay (0νββ is perhaps the only experiment that can tell us whether the neutrino is a Dirac or a Majorana particle. Given the significance of the 0νββ, there is a widespread interest for these rare event studies employing a variety of novel techniques. An essential criterion for detector design is the high energy resolution for a precision measurement of the sum energy of two electrons emitted in 0νββ decay. The low temperature bolometric detectors are ideally suited for this purpose. In India, efforts have been initiated to search for 0νββ in 124Sn at the upcoming underground facility of India based Neutrino Observatory (INO. A custom built cryogen free dilution refrigerator has been installed at TIFR, Mumbai for the development of Sn prototype bolometer. A base temperature of 10 mK has been achieved in this setup. This paper gives a brief description of efforts towards Sn bolometer development.

  1. Double beta decay versus cosmology: Majorana CP phases and nuclear matrix elements

    Deppisch, F; Suhonen, J; Deppisch, Frank; P\\"as, Heinrich; Suhonen, Jouni

    2004-01-01

    We discuss the relation between the absolute neutrino mass scale, the effective mass measured in neutrinoless double beta decay, and the Majorana CP phases. Emphasis is placed on estimating the upper bound on the nuclear matrix element entering calculations of the double beta decay half life. Consequently, one of the Majorana CP phases can be constrained when combining the claimed evidence for neutrinoless double beta decay with the neutrino mass bound from cosmology.

  2. Test of the single state dominance hypothesis for the two-neutrino double beta decay

    Moreno, O; Alvarez-Rodriguez, R; Moya de Guerra, E [Dpto. Fisica Atom., Mol. y Nuclear, University Complutense de Madrid, E-28040 Madrid (Spain); Sarriguren, P [Instituto de Estructura de la Materia, CSIC, Serrano 123, E-28006 Madrid (Spain); Simkovic, F [Department of Nuclear Physics, Comenius University, SK-842 15 Bratislava (Slovakia); Faessler, Amand, E-mail: oscar.moreno@iem.cfmac.csic.e [Institut fuer Theoretische Physik, Universitaet Tuebingen, D-72076 Tuebingen (Germany)

    2010-01-01

    The single state dominance hypothesis for the two-neutrino double-beta decay matrix elements is tested in this work for the double-beta decaying nuclei {sup 100}Mo, {sup 116}Cd, and {sup 128}Te. In addition to this, we analyze the contribution to the double-beta matrix elements from the low-lying intermediate states and from the whole set of intermediate states. We use a proton-neutron QRPA calculation based on a deformed Skyrme Hartree-Fock mean field with pairing correlations, and we compare these results with the half-lives of the double-beta emitters for which we have experimental information.

  3. Measurement of the Double-Beta Decay Half-Life and Search for the Neutrinoless Double-Beta Decay of $^{48}{\\rm Ca}$ with the NEMO-3 Detector

    :,; Augier, C; Bakalyarov, A M; Baker, J D; Barabash, A S; Basharina-Freshville, A; Blondel, S; Blot, S; Bongrand, M; Brudanin, V; Busto, J; Caffrey, A J; Calvez, S; Cascella, M; Cerna, C; Cesar, J P; Chapon, A; Chauveau, E; Chopra, A; Duchesneau, D; Durand, D; Egorov, V; Eurin, G; Evans, J J; Fajt, L; Filosofov, D; Flack, R; Garrido, X; Gómez, H; Guillon, B; Guzowski, P; Hodák, R; Huber, A; Hubert, P; Hugon, C; Jullian, S; Klimenko, A; Kochetov, O; Konovalov, S I; Kovalenko, V; Lalanne, D; Lang, K; Lebedev, V I; Lemière, Y; Noblet, T Le; Liptak, Z; Liu, X R; Loaiza, P; Lutter, G; Mamedov, F; Marquet, C; Mauger, F; Morgan, B; Mott, J; Nemchenok, I; Nomachi, M; Nova, F; Nowacki, F; Ohsumi, H; Pahlka, R B; Perrot, F; Piquemal, F; Povinec, P; Přidal, P; Ramachers, Y A; Remoto, A; Reyss, J L; Richards, B; Riddle, C L; Rukhadze, E; Rukhadze, N I; Saakyan, R; Salazar, R; Sarazin, X; Shitov, Yu; Simard, L; Šimkovic, F; Smetana, A; Smolek, K; Smolnikov, A; Söldner-Rembold, S; Soulé, B; Štekl, I; Suhonen, J; Sutton, C S; Szklarz, G; Thomas, J; Timkin, V; Torre, S; Tretyak, Vl I; Tretyak, V I; Umatov, V I; Vanushin, I; Vilela, C; Vorobel, V; Waters, D; Zhukov, S V; Žukauskas, A

    2016-01-01

    The NEMO-3 experiment at the Modane Underground Laboratory has investigated the double-$\\beta$ decay of $^{48}{\\rm Ca}$. Using $5.25$\\,yr of data recorded with a $6.99\\,{\\rm g}$ sample of $^{48}{\\rm Ca}$, approximately $150$ double-$\\beta$ decay candidate events have been selected with a signal-to-background ratio greater than $3$. The half-life for the two-neutrino double-$\\beta$ decay of $^{48}{\\rm Ca}$ has been measured to be \\mbox{$T^{2\

  4. Measurement of the double-beta decay half-life and search for the neutrinoless double-beta decay of $^{48}{\\rm Ca}$ with the NEMO-3 detector

    Collaboration, NEMO-3; :; Arnold, R.; Augier, C.; Bakalyarov, A. M.; Baker, J. D.; Barabash, A. S.; Basharina-Freshville, A.; Blondel, S.; Blot, S; Bongrand, M.; Brudanin, V.(Joint Institute for Nuclear Research, Dubna, Russia); Busto, J.; Caffrey, A. J.; S. Calvez

    2016-01-01

    The NEMO-3 experiment at the Modane Underground Laboratory has investigated the double-$\\beta$ decay of $^{48}{\\rm Ca}$. Using $5.25$ yr of data recorded with a $6.99\\,{\\rm g}$ sample of $^{48}{\\rm Ca}$, approximately $150$ double-$\\beta$ decay candidate events have been selected with a signal-to-background ratio greater than $3$. The half-life for the two-neutrino double-$\\beta$ decay of $^{48}{\\rm Ca}$ has been measured to be $T^{2\

  5. The low background spectrometer TGV II for double beta decay measurements

    Benes, P. [Institute of Experimental and Applied Physics, CTU in Prague, Horska 3a/22, 128 00 Prague (Czech Republic); Cermak, P. [Institute of Experimental and Applied Physics, CTU in Prague, Horska 3a/22, 128 00 Prague (Czech Republic)]. E-mail: pavel.cermak@utef.cvut.cz; Gusev, K.N. [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Klimenko, A.A. [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Kovalenko, V.E. [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Kovalik, A. [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Nuclear Physics Institute of the CAS, 25263 Rez near Prague (Czech Republic); Rukhadze, N.I. [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Salamatin, A.V. [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Simkovic, F. [Comenius University in Bratislava, SK-842 15 Bratislava (Slovakia); Stekl, I. [Institute of Experimental and Applied Physics, CTU in Prague, Horska 3a/22, 128 00 Prague (Czech Republic); Timkin, V.V. [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Vylov, Ts. [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation)

    2006-12-21

    The low-background multi-HPGe spectrometer TGVII installed in the Modane Underground Laboratory (France) is described in detail and the results of the background measurements are reported. The spectrometer is focused on the double beta decay measurements with two isotopes-{sup 106}Cd (2{nu}EC/EC mode) and {sup 48}Ca ({beta}{beta} mode). A basic summary of the physics of {beta}{beta} decay (especially EC/EC mode) is also given.

  6. Search for the Neutrino Less Double Beta Decay

    Efremenko, Yuri [Univ. of Tennessee, Knoxville, TN (United States). Dept. of Physics and Astronomy

    2016-07-11

    During the past few years our understanding of neutrino properties has reached a new level, with experiments such as Super-K, SNO, KamLAND, and others obtaining exciting results. Major questions such as “Do neutrinos have mass?” and “Do neutrinos oscillate?” now have positive answers. However, an extensive program of neutrino research remains. Undoubtedly, the most important of these is the question pointed out by the National Research Council in its February 2002 report “Connecting Quarks with the Cosmos”, specifically: What are the masses of neutrinos and how have they shaped the evolution of the Universe? The MAJORANA collaboration has proposed to build the world’s most sensitive one-ton scale experiment to search for neutrino less double beta decay to answer this question. In its initial stage, the collaboration is building a prototype MAJORANA DEMONSTRATOR (MJD) experiment consisting of detectors made out of enriched Ge76 with a total sensitive mass of ~30 kg. This will accomplish two goals. First, it will test not yet confirmed claim for observation of neutrino-less double beta decay. Second, it will establish that the selected technology is capable of extension to a one-ton experiment with sufficient sensitivity to measure neutrino mass mββ down to 10 meV. To achieve the last goal, collaboration must demonstrate that a background level of 1 count per year per 4 keV per ton of detector is achievable. The University of Tennessee (UT) neutrino group has made a major commitment to the MJD. P.I. accepted the responsibility for one of the major tasks of the experiment, “Materials and Assay Task” which is crucial to the achievement of low background levels required for the experiment. In addition, the UT group is committed to construct, commission, and operate the MJD active veto system. Those activities were supported by NP-DOE via program funding for “Search for the Neutrino Less Double Beta Decay” at the University

  7. An electroweak basis for neutrinoless double $\\beta$ decay

    Graesser, Michael L

    2016-01-01

    A discovery of neutrinoless double-$\\beta$ decay would be profound, providing the first direct experimental evidence of lepton number violating processes. While a natural explanation is provided by an effective Majorana neutrino mass, other new physics interpretations should be carefully evaluated. At low--energies such new physics could manifest itself in the form of color and $SU(2)_L \\times U(1)_{Y}$ invariant higher dimension operators. Here we determine a complete set of electroweak invariant dimension--9 operators, and our analysis supersedes those that only impose $U(1)_{em}$ invariance. Imposing electroweak invariance implies: 1) a significantly reduced set of leading order operators compared to only imposing $U(1)_{em}$ invariance; and 2) other collider signatures. Prior to imposing electroweak invariance we find 32 dimension-9 operators, which is reduced to 15 electroweak invariant operators at leading order in the expansion in the Higgs vacuum expectation value. We set up a systematic analysis of t...

  8. An experimental investigation of double beta decay of 100Mo

    New limits on half-lives for several double beta decay modes of 100Mo were obtained with a novel experimental system which included thin source films interleaved with a coaxial array of windowless silicon detectors. Segmentation and timing information allowed backgrounds originating in the films to be studied in some detail. Dummy films containing 96Mo were used to assess remaining backgrounds. With 0.1 mole years of 100Mo data collected, the lower half-life limits at 90% confidence were 2.7 /times/ 1018 years for decay via the two-neutrino mode, 5.2 /times/1019 years for decay with the emission of a Majoron, and 1.6 /times/ 1020 years and 2.2 /times/ 1021 years for neutrinoless 0+ → 2+ and 0+ → 0+ transitions, respectively. 50 refs., 38 figs., 11 tabs

  9. Cryogenic Double Beta Decay Experiments: CUORE and CUORICINO

    Maruyama, Reina

    2008-01-01

    Cryogenic bolometers, with their excellent energy resolution, flexibility in material, and availability in high purity, are excellent detectors for the search for neutrinoless double beta decay. Kilogram-size single crystals of TeO_2 are utilized in CUORICINO for an array with a total detector mass of 40.7 kg. CUORICINO currently sets the most stringent limit on the halflife of Te-130 of T > 2.4x10^{24} yr (90% C.L.), corresponding to a limit on the effective Majorana neutrino mass in the range of < 0.2-0.9 eV. Based on technology developed for CUORICINO and its predecessors, CUORE is a next-generation experiment designed to probe neutrino mass in the range of 10 - 100 meV. Latest results from CUORICINO and overview of the progress and current status of CUORE are presented.

  10. Neutrinoless double-beta decay in covariant density functional theory

    Ring, P.; Yao, J. M.; Song, L. S.; Hagino, K.; Meng, J.

    2015-10-01

    We use covariant density functional theory beyond mean field in order to describe neutrinoless double-beta decay in a fully relativistic way. The dynamic effects of particle-number and angular-momentum conservations as well as shape fluctuations of quadrupole character are taken into account within the generator coordinate method for both initial and final nuclei. The calculations are based on the full relativistic transition operator. The nuclear matrix elements (NME's) for a large number of possible transitions are investigated. The results are compared with various non-relativistic calculations, in particular also with the density functional theory based on the Gogny force. We find that the non-relativistic approximation is justified and that the total NME's can be well approximated by the pure axial-vector coupling term. This corresponds to a considerable reduction of the computational effort.

  11. Neutrinoless double-beta decay in covariant density functional theory

    Ring, P., E-mail: ring@ph.tum.de [Physik-Department der Technischen Universität München, D-85748 Garching (Germany); State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking Univ., Beijing 100871 (China); Yao, J. M. [Department of Physics, Tohoku University, Sendai 980-8578 (Japan); School of Physical Science and Technology, Southwest University, Chongqing 400715 (China); Song, L. S. [State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking Univ., Beijing 100871 (China); Hagino, K. [Department of Physics, Tohoku University, Sendai 980-8578 (Japan); Meng, J. [State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking Univ., Beijing 100871 (China); School of Physics and Nuclear Energy Engineering, Beihang University, Beijing 100191 (China); Department of Physics, University of Stellenbosch, Stellenbosch 7602 (South Africa)

    2015-10-15

    We use covariant density functional theory beyond mean field in order to describe neutrinoless double-beta decay in a fully relativistic way. The dynamic effects of particle-number and angular-momentum conservations as well as shape fluctuations of quadrupole character are taken into account within the generator coordinate method for both initial and final nuclei. The calculations are based on the full relativistic transition operator. The nuclear matrix elements (NME’s) for a large number of possible transitions are investigated. The results are compared with various non-relativistic calculations, in particular also with the density functional theory based on the Gogny force. We find that the non-relativistic approximation is justified and that the total NME’s can be well approximated by the pure axial-vector coupling term. This corresponds to a considerable reduction of the computational effort.

  12. Neutrinoless double-beta decay in covariant density functional theory

    We use covariant density functional theory beyond mean field in order to describe neutrinoless double-beta decay in a fully relativistic way. The dynamic effects of particle-number and angular-momentum conservations as well as shape fluctuations of quadrupole character are taken into account within the generator coordinate method for both initial and final nuclei. The calculations are based on the full relativistic transition operator. The nuclear matrix elements (NME’s) for a large number of possible transitions are investigated. The results are compared with various non-relativistic calculations, in particular also with the density functional theory based on the Gogny force. We find that the non-relativistic approximation is justified and that the total NME’s can be well approximated by the pure axial-vector coupling term. This corresponds to a considerable reduction of the computational effort

  13. The MAJORANA DEMONSTRATOR Neutrinoless Double-Beta Decay Experiment

    Abgrall, N.; Aguayo, Estanislao; Avignone, Frank T.; Barabash, Alexander S.; Bertrand, F.; Boswell, M.; Brudanin, V.; Busch, Matthew; Caldwell, A. S.; Chan, Yuen-Dat; Christofferson, Cabot-Ann; Combs, Dustin C.; Detwiler, Jason A.; Doe, Peter J.; Efremenko, Yuri; Egorov, Viatcheslav; Ejiri, H.; Elliott, S. R.; Esterline, James H.; Fast, James E.; Finnerty, P.; Fraenkle, Florian; Galindo-Uribarri, A.; Giovanetti, G. K.; Goett, J.; Green, M.; Gruszko, J.; Guiseppe, Vincente; Gusev, K.; Hallin, A. L.; Hazama, R.; Hegai, A.; Henning, Reyco; Hoppe, Eric W.; Howard, Stanley; Howe, M. A.; Keeter, K.; Kidd, M. F.; Knecht, A.; Kochetov, Oleg; Konovalov, S.; Kouzes, Richard T.; Laferriere, Brian D.; Leon, Jonathan D.; Leviner, L.; Loach, J. C.; Luke, P.; MacMullin, S.; Martin, R. D.; Mertens, S.; Mizouni, Leila; Nomachi, Masaharu; Orrell, John L.; O' Shaughnessy, C.; Overman, Nicole R.; Phillips, David; Poon, Alan; Pushkin, K.; Radford, D. C.; Rielage, Keith; Robertson, R. G. H.; Ronquest, M. C.; Schubert, Alexis G.; Shanks, B.; Shima, T.; Shirchenko, M.; Snavely, Kyle J.; Snyder, N.; Steele, David; Strain, J.; Suriano, Anne-Marie; Thompson, J.; Timkin, V.; Tornow, Werner; Varner, R. L.; Vasilyev, Sergey; Vetter, Kai; Vorren, Kris R.; White, Brandon R.; Wilkerson, J. F.; Williams, T.; Xu, W.; Yakushev, E.; Young, A.; Yu, Chang-Hong; Yumatov, Vladimir

    2014-06-01

    The MAJORANA DEMONSTRATOR will search for the neutrinoless double-beta (ββ(0ν)) decay of the isotope 76Ge with a mixed array of enriched and natural germanium detectors. The observation of this rare decay would indicate that the neutrino is its own antiparticle, demonstrate that lepton number is not conserved, and provide information on the absolute mass scale of the neutrino. The DEMONSTRATOR is being assembled at the 4850-foot level of the Sanford Underground Research Facility in Lead, South Dakota. The array will be situated in a low-background environment and surrounded by passive and active shielding. Here we describe the science goals of the DEMONSTRATOR and the details of its design.

  14. The MAJORANA DEMONSTRATOR Neutrinoless Double-Beta Decay Experiment

    Abgrall, N.; Aguayo, Estanislao; Avignone, III, F. T.; Barabash, A.; Bertrand, F.; Boswell, M.; Brudanin, V.; Busch, Matthew; Caldwell, A. S.; Chan, Yuen-Dat; Christofferson, Cabot-Ann; Combs, Dustin C.; Detwiler, Jason A.; Doe, Peter J.; Efremenko, Yuri; Egorov, Viatcheslav; Ejiri, H.; Elliott, S. R.; Esterline, James H.; Fast, James E.; Finnerty, P.; Fraenkle, Florian; Galindo-Uribarri, A.; Giovanetti, G. K.; Goett, J.; Green, M.; Gruszko, J.; Guiseppe, Vincente; Gusev, K.; Hallin, A. L.; Hazama, R.; Hegai, A.; Henning, Reyco; Hoppe, Eric W.; Howard, Stanley; Howe, M. A.; Keeter, K.; Kidd, M. F.; Knecht, A.; Kochetov, Oleg; Konovalov, S.; Kouzes, Richard T.; Laferriere, Brian D.; Leon, Jonathan D.; Leviner, L.; Loach, J. C.; Luke, P.; MacMullin, S.; Martin, R. D.; Mertens, S.; Mizouni, Leila; Nomachi, Masaharu; Orrell, John L.; O' Shaughnessy, Mark D.; Overman, Nicole R.; Phillips, David; Poon, Alan; Pushkin, K.; Radford, D. C.; Rielage, Keith; Robertson, R. G. H.; Ronquest, M. C.; Schubert, Alexis G.; Shanks, B.; Shima, T.; Shirchenko, M.; Snavely, Kyle J.; Snyder, N.; Steele, David; Strain, J.; Suriano, Anne-Marie; Thompson, J.; Timkin, V.; Tornow, Werner; Varner, R. L.; Vasilyev, Sergey; Vetter, Kai; Vorren, Kris R.; White, Brandon R.; Wilkerson, J. F.; Williams, T.; Xu, W.; Yakushev, E.; Young, A.; Yu, Chang-Hong; Yumatov, Vladimir

    2014-01-01

    The Majorana Demonstrator will search for the neutrinoless double-beta (ββ (0ν)) decay of the isotope 76Ge with a mixed array of enriched and natural germanium detectors. The observation of this rare decay would indicate that the neutrino is its own antiparticle, demonstrate that lepton number is not conserved, and provide information on the absolute mass scale of the neutrino. TheDemonstrator is being assembled at the 4850-foot level of the SanfordUnderground Research Facility in Lead, SouthDakota. The array will be situated in a low-background environment and surrounded by passive and active shielding. Here we describe the science goals of the Demonstrator and the details of its design.

  15. Recent results from cosmology and neutrinoless double beta decay

    Dell’Oro, Stefano; Marcocci, Simone

    2016-05-01

    We quantify the impact of cosmological surveys on the search for neutrinoless double beta decay (0vββ) within the hypothesis that the 0vββ rate is dominated by the Majorana mass of ordinary neutrinos. In particular, we exploit the potential relevance of the work of Palanque-Delabrouille et al. [JCAP 1502, 045 (2015)], whose result seems to favor the normal hierarchy spectrum for the light neutrino masses. The impact of our analysis for the future generation of 0vββ experiments is quite dramatic and motivates further cosmological studies, both theoretically and experimentally. In fact, the allowed values for the Majorana Effective Mass turn out to be < 75meV at 3σ C.L, lowering down to less than 20 meV at 1σ C.L.

  16. Ground state occupation probabilities of neutrinoless double beta decay candidates

    Kotila, Jenni; Barea, Jose

    2015-10-01

    A better understanding of nuclear structure can offer important constraints on the calculation of 0 νββ nuclear matrix elements. A simple way to consider differences between initial and final states of neutrinoless double beta decay candidates is to look at the ground state occupation probabilities of initial and final nuclei. As is well known, microscopic interacting boson model (IBM-2) has found to be very useful in the description of detailed aspects of nuclear structure. In this talk I will present results for ground state occupation probabilities obtained using IBM-2 for several interesting candidates of 0 νββ -decay. Comparison with recent experimental results is also made. This work was supported Academy of Finland (Project 266437) and Chilean Ministry of Education (Fondecyt Grant No. 1150564),

  17. Nuclear transparency and double beta decay of molybdenum 100

    Work is continuing on two collaborative experiments. One, a search for double beta decay in molybdenum 100 is being carried out in the Consil silver mine in Osburn, Idaho with collaborators from the Lawrence Berkeley Laboratory, the University of New Mexico, and the Idaho National Engineering Laboratory. At this time the experiment is running with 62 foils, each with a mass of about .98 grams of isotopically enriched molybdenum 100. In approximately 1870 hours of data taking which began during the spring 1991 we have obtained a preliminary 1σ lower limit of .12 x 1023 years for the lifetime for O+ → O+ neutrionoless double beta decay in molybdenum 100 based on an estimate for the event detection efficiency of the upgraded detector. This lifetime limit is 3 times greater that the one we published previously in Physical Review Letters in 1989. Monte Carlo Efforts are currently underway to determine the event detector efficiency more precisely. The second experiment involves the construction of a cylindrically symmetrical detector at the Brookhaven National Laboratory AGS to study color transparency in nuclei from 6 to 20 GeV/c. This detector consists of a large superconducting solenoidal magnet, a cylinder of scintillating fibers, several cylinders of straw tubes, and an array of trigger plastic scintillator hodoscopes. Mount Holyoke has been principally involved in the design of phototube bases for the trigger hodoscopes for the EVA detector and in the design and construction of the scintillating fiber detector tracking detector. A prototype fiber detector consisting of 2 Hamamatsu multianode photomultiplier tubes with 256 channels each and approximately 650 1.5 meter long 1 mm diameter scintillating fibers broken up into two layers and supported by a 10 centimeter diameter carbon fiber tube was constructed for the spring high energy physics run at the AGS. Data from this run obtained from the detector is included in this report

  18. Theory of neutrinoless double-beta decay - a brief review

    Neutrinoless double-beta decay (0νββ-decay) is a unique probe for lepton number conservation and neutrino properties. This is a process with long and interesting history with important implications for particle physics and cosmology, but its observation is still elusive. The search for the 0νββ-decay represents the new frontiers of neutrino physics, allowing one to determine the Majorana nature of neutrinos and to fix the neutrino mass scale and possible CP-violation effects, which could explain the matter-antimatter asymmetry in the Universe. At present, a complete theory is missing and, thus, to motivate and guide the experiments, the mechanism mediated by light neutrinos is mostly considered. The subject of interest is an effective mass of Majorana neutrinos, which can be deduced from the measured half-life, once this process is definitely observed. The accuracy of the determination of this quantity is mainly determined by our knowledge of the nuclear matrix elements. There is a request to evaluate them with high precision, accuracy and reliability. Recently, there is an increased interest in the resonant neutrinoless double-electron capture, which may also establish the Majorana nature of neutrinos. This possibility is considered as alternative and complementary to searches for the 0νββ-decay

  19. LUCIFER: scintillating bolometers for neutrinoless double-beta decay searches

    Pattavina, Luca

    2014-09-01

    In the field of fundamental particle physics, the nature of the neutrino, if it is a Dirac or a Majorana particle, plays a crucial role not only in neutrino physics, but also in the overall framework of fundamental particle interactions and in cosmology. Neutrinoless double-beta decay (0vDBD) is the key tool for the investigation of this nature. Experimental techniques based on the calorimetric approach with cryogenic particle detectors have demonstrated suitability for the investigation of rare nuclear processes, profiting from excellent energy resolution and scalability to large masses. Unfortunately, the most relevant issue is related to background suppression. In fact, bolometers being fully-active detectors struggle to reach extremely low background level. The LUCIFER project aims to deploy the first array of enriched scintillating bolometers. Thanks to the double read-out - heat and scintillation light produced by scintillating bolometers - a highly efficient background identification and rejection is guaranteed, leading to a background-free experiment. We show the potential of such technology in ZnMoO4 and ZnSe prototypes. We describe the current status of the project, including results of the recent R&D activity.

  20. Analysis of the data from the NEMO3 experiment and search for neutrinoless double beta decay - Study of systematic bias of the calorimeter and development of analysis tools

    The NEMO3 experiment was researching the neutrinoless double-β (0ndb) decay by using various sources of double beta decay isotopes (mainly 100Mo, 82Se, 116Cd and 130Te for about 10 kg in total). The detector was located in the underground laboratory of Modane (Italy) in the halfway point of the Frejus tunnel. This experiment demonstrated that the 'tracko-calo' technology is really competitive and, in addition, it gives new results for the 2-neutrinos double-β (2ndb) decay and the (0ndb) decays research. Moreover it opened an new way for its successor SuperNEMO, which aim is to reach a mass of 100 kg of 82Se (for a sensitivity of 1026 years). The main goal of the thesis is to measure the 2ndb and 0ndb decay of the 100Mo to the excited state 01+ of the 100Ru thanks to the whole NEMO3 data, with new original methods of analysis and through the development of the collaboration analysis software. The results obtained for the ground states (gs) and excited states 2ndb of the 100Mo are for the half-lives: T(2nbd, gs)=[7.05±0.01(stat)±0.54(syst)]*1018 years and T(2ndb, 01+)=[6.15±1.1(sta)±0.78]*1020 years. Those results are compatibles with the last ones published by the collaboration. For the 0ndb(01+), this work gave a half-life of T(0ndb, 01+) > 2.6*1023 years, improving significantly the last published results. Furthermore those methods also allowed to present a new and more exhaustive background noise model for this experiment. The second point of this work was to measure the systematics errors of the NEMO3 calorimeter, among others due to the wavelength of the NEMO3 calibration systems. This work was done using a new test bench based on LED. This bench also allowed to contribute to the development of the SuperNEMO calorimeter, especially in the time characteristic and the energy linearity measurement of the photomultiplier intended to the demonstrator of the experiments. (author)

  1. Nuclear responses for neutrinos and neutrino studies by double beta decays and inverse beta decays

    H Ejiri

    2001-08-01

    This is a brief report on recent studies of nuclear responses for neutrinos () by charge exchange reactions, masses by double beta () decays and of solar and supernova ’s by inverse decays. Subjects discussed include (1) studies in nuclear micro-laboratories, (2) masses studied by decays of 100Mo and nuclear responses for -, (3) solar and supernova ’s by inverse decays and responses for 71Ga and 100Mo, and (4) MOON (molybdenum observatory of neutrinos) for spectroscopic studies of Majorana masses with sensitivity of ∼ 0.03 eV by decays of 100Mo and real-time studies of low energy solar and supernova ’s by inverse decays of 100Mo.

  2. The Gerda search for neutrinoless double beta decay

    O'Shaughnessy, Christopher; Gerda Collaboration

    2013-10-01

    The Germanium Detector Array (Gerda) is a search for the neutrinoless double beta decay of 76Ge. High Purity Germanium (HPGe) detectors enriched in the isotope-76 are operated bare in liquid argon (LAr). LAr is used for both cooling of the HPGe diodes to their operating temperatures and for shielding from external radiation sources. From the measurements of the first phase that began data taking on 1 Nov. 2011 it is expected to have a sensitivity on the level of T1/2>2E25 yr at a 90% CL after 15 kġyr. The goal of this phase will be to probe the claim of an observation by part of the Heidelberg-Moscow collaboration. Efforts will then focus on increasing the sensitivity of the experiment by deploying additional enriched detectors that are in an advanced stage of production and by reducing the background index further by making use of pulse shape discrimination techniques as well as an active LAr veto. While the 0νββ region of interest continues to remain blinded, here the status of Phase-I data taking is presented along with the work towards improving the experimental sensitivity.

  3. Semiconductor-based experiments for neutrinoless double beta decay search

    Barnabé Heider, Marik; Gerda Collaboration

    2012-08-01

    Three experiments are employing semiconductor detectors in the search for neutrinoless double beta (0νββ) decay: COBRA, Majorana and GERDA. COBRA is studying the prospects of using CdZnTe detectors in terms of achievable energy resolution and background suppression. These detectors contain several ββ emitters and the most promising for 0νββ-decay search is 116Cd. Majorana and GERDA will use isotopically enriched high purity Ge detectors to search for 0νββ-decay of 76Ge. Their aim is to achieve a background ⩽10-3 counts/(kgṡyṡkeV) at the Q improvement compared to the present state-of-art. Majorana will operate Ge detectors in electroformed-Cu vacuum cryostats. A first cryostat housing a natural-Ge detector array is currently under preparation. In contrast, GERDA is operating bare Ge detectors submerged in liquid argon. The construction of the GERDA experiment is completed and a commissioning run started in June 2010. A string of natural-Ge detectors is operated to test the complete experimental setup and to determine the background before submerging the detectors enriched in 76Ge. An overview and a comparison of these three experiments will be presented together with the latest results and developments.

  4. Purification of lanthanides for double beta decay experiments

    Polischuk, O. G.; Barabash, A. S.; Belli, P.; Bernabei, R.; Boiko, R. S.; Cappella, F.; Cerulli, R.; Danevich, F. A.; Incicchitti, A.; Laubenstein, M.; Mokina, V. M.; Nisi, S.; Poda, D. V.; Tretyak, V. I.

    2013-08-01

    There are several potentially double beta active isotopes among the lanthanide elements. However, even high purity grade lanthanide compounds contain 238U, 226Ra and 232,228Th typically on the level of ˜ (0.1 - 1) Bq/kg. The liquid-liquid extraction technique was used to remove traces of U, Ra and Th from CeO2, Nd2O3 and Gd2O3. The radioactive contamination of the samples before and after the purification was tested by using ultra-low-background HPGe γ spectrometry at the underground Gran Sasso National Laboratories of the INFN (Italy). After the purification the radioactive contamination of gadolinium oxide by Ra and Th was decreased at least one order of magnitude. The efficiency of the approach to purify cerium oxide from Ra was on same level, while the radioactive contamination of neodymium sample before and after the purification is below the sensitivity of analytical methods. The purification method is much less efficient for chemically very similar radioactive elements like lanthanum, lutetium and actinium. R&D of the methods to remove the pollutions with improved efficiency is in progress.

  5. Measurement of double-beta-decay—experiments TGV and NEMO

    Štekl, I.

    2001-06-01

    A description of the aim and present status of the experiments NEMO and TGV are presented. The NEMO collaboration developed the detector NEMO-2 to investigate double-beta ( ββ) decay of 100Mo, 116Cd, 82Se and 96Zr. The results obtained for the above mentioned isotopes are given. The new detector NEMO-3, which is approximately 20 times larger than NEMO-2, is under construction. The NEMO-3 detector should allow the study of 0 νββ decays of 100Mo (or other isotopes) with half-life ˜10 25years, corresponding to neutrino masses of 0.1- 0.3 eV. The TGV I collaboration has studied the ββ decay of 48Ca. The result T 2 νββ1/2=(4.2 +3.3-1.3)×10 19 years has been found. Experiment TGV II is devoted to measurement of the ββ decay (β +β +, β +/ EC, EC/ EC) of 106Cd, particularly the 2 νEC/EC mode.

  6. Measurement of double-beta-decay--experiments TGV and NEMO

    A description of the aim and present status of the experiments NEMO and TGV are presented. The NEMO collaboration developed the detector NEMO-2 to investigate double-beta (ββ) decay of 100Mo, 116Cd, 82Se and 96Zr. The results obtained for the above mentioned isotopes are given. The new detector NEMO-3, which is approximately 20 times larger than NEMO-2, is under construction. The NEMO-3 detector should allow the study of 0νββ decays of 100Mo (or other isotopes) with half-life ∼1025 years, corresponding to neutrino masses of 0.1-0.3 eV. The TGV I collaboration has studied the ββ decay of 48Ca. The result T2νββ1/2=(4.2+3.3-1.3)x1019 years has been found. Experiment TGV II is devoted to measurement of the ββ decay (β+β+, β+/EC, EC/EC) of 106Cd, particularly the 2νEC/EC mode. (author)

  7. Theoretical and Experimental Considerations for Neutrinoless Double Beta Decay

    Castillo, O; Grosse-Oetringhaus, J F; Lenzi, B; Panes, B; Tibbetts, M; Valenzuela, C; Yacoob, S; Yagues, A G; Zanetti, C

    2008-01-01

    In the rst part of this work we show some theoretical aspects of the generation of the neutrino mass by means of a direct extension of the Standard Model of particles, which include the presence of heavy right-handed neutrinos and large Majorana mass terms. From these two new ingredients, it is possible to nd a mass for the light neutrinos which is naturally of the order of 1 eV or less. The idea is to put these theoretical aspects in the context of the search for neutrino mass values by the study of the signal from the Neutrinoless Double Beta Decay Process (0 ). In the second part, a brief summary is given of the experimental considerations required for the measurement of effective Majorana neutrino mass using (0 ). Measurement strategies and background considerations are introduced and an outline of both active and passive methods is given. Finally, current results are discussed with particular emphasis on the Heidelberg–Moscow experiment. This note is based on the presentation given at the CERN–CLAF 4th...

  8. LUCIFER: Neutrinoless Double Beta decay search with scintillating bolometers

    One of the fundamental open questions in elementary particle physics is the value of the neutrino mass and its nature of Dirac or Majorana particle. Neutrinoless double beta decay (DBD0ν) is a key tool for investigating these neutrino properties and for finding answers to the open questions concerning mass hierarchy and absolute scale. Experimental techniques based on the calorimetric approach with cryogenic particle detectors are proved to be suitable for the search of this rare decay, thanks to high energy resolution and large mass of the detectors. One of the main issues to access an increase of the experimental sensitivity is strictly related to background reduction, trying to perform possibly a zero background experiment. The LUCIFER (Low-background Underground Cryogenic Installation For Elusive Rates) project, funded by the European Research Council, aims at building a background-free DBD0ν experiment, with a discovery potential comparable with the present generation experiments. The idea of LUCIFER is to measure, simultaneously, heat and scintillation light with ZnSe bolometers. Detector features and operational procedures are reviewed. The expected performances and sensitivity are also discussed.

  9. Nuclear-structure aspects of double beta decay

    Neutrinoless double beta (0νββ) decay of nuclei is a process that requires the neutrino to be a massive Majorana particle and thus cannot proceed in the standard model of electro-weak interactions. Recent results of the neutrino-oscillation experiments have produced accurate information on the mixing of neutrinos and their squared mass differences. The 0νββ decay takes place in atomic nuclei where it can be observed, at least in principle, by underground neutrino experiments. The need of nuclei in observation of the 0νββ decay bears two facets: The nucleus serves as laboratory for detection but at the same time its complicated many-nucleon structure interferes strongly with the analysis of the experimental data. The information about the weak-interaction observables, like the neutrino mass, has to be filtered from the data through the nuclear matrix elements (NMEs). Hence, exact knowledge about the NMEs is of paramount importance in the analysis of the data provided by the expensive and time-consuming underground experiments.

  10. Purification of lanthanides for double beta decay experiments

    Polischuk, O. G. [Institute for Nuclear Research, MSP 03680 Kyiv, Ukraine and INFN, Section of Rome, La Sapienza, I-00185 Rome (Italy); Barabash, A. S. [Institute of Theoretical and Experimental Physics, 117259 Moscow (Russian Federation); Belli, P. [INFN, Section of Rome Tor Vergata, I-00133 Rome (Italy); Bernabei, R. [INFN, Section of Rome Tor Vergata, I-00133 Rome, Italy and Department of Physics, University of Rome Tor Vergata, I-00133 Rome (Italy); Boiko, R. S.; Danevich, F. A.; Mokina, V. M.; Poda, D. V.; Tretyak, V. I. [Institute for Nuclear Research, MSP 03680 Kyiv (Ukraine); Cappella, F.; Incicchitti, A. [INFN, Section of Rome La Sapienza, I-00185 Rome, Italy and Department of Physics, University of Rome La Sapienza, I-00185 Rome (Italy); Cerulli, R.; Laubenstein, M.; Nisi, S. [INFN, Gran Sasso National Laboratories, I-67100 Assergi (Aq) (Italy)

    2013-08-08

    There are several potentially double beta active isotopes among the lanthanide elements. However, even high purity grade lanthanide compounds contain {sup 238}U, {sup 226}Ra and {sup 232,228}Th typically on the level of ∼ (0.1 - 1) Bq/kg. The liquid-liquid extraction technique was used to remove traces of U, Ra and Th from CeO{sub 2}, Nd{sub 2}O{sub 3} and Gd{sub 2}O{sub 3}. The radioactive contamination of the samples before and after the purification was tested by using ultra-low-background HPGe γ spectrometry at the underground Gran Sasso National Laboratories of the INFN (Italy). After the purification the radioactive contamination of gadolinium oxide by Ra and Th was decreased at least one order of magnitude. The efficiency of the approach to purify cerium oxide from Ra was on same level, while the radioactive contamination of neodymium sample before and after the purification is below the sensitivity of analytical methods. The purification method is much less efficient for chemically very similar radioactive elements like lanthanum, lutetium and actinium. R and D of the methods to remove the pollutions with improved efficiency is in progress.

  11. Getting Information on |Ue3|2 from Neutrinoless Double Beta Decay

    Alexander Merle

    2007-01-01

    neutrinoless double beta decay. We show that typically a lower limit on |Ue3| as a function of the smallest neutrino mass can be set. Furthermore, we give the values of the sum of neutrino masses and |Ue3| which are allowed and forbidden by an experimental upper limit on the effective mass. Alternative explanations for neutrinoless double beta decay, Dirac neutrinos or unexplained cosmological features would be required if future measurements showed that the values lie in the respective regions. Moreover, we show that a measurement of |Ue3| from neutrinoless double beta decay is very difficult due to the expected errors on the effective mass and the oscillation parameters.

  12. On Gamow-Teller strength distributions for $\\beta\\beta$-decaying nuclei within continuum-QRPA

    Igashov, S Yu; Faessler, Amand; Urin, M H

    2010-01-01

    An isospin-selfconsistent pn-continuum-QRPA approach is formulated and applied to describe the Gamow-Teller strength distributions for $\\beta\\beta$-decaying open-shell nuclei. The calculation results obtained for the pairs of nuclei $^{76}$Ge-Se, $^{100}$Mo-Ru, $^{116}$Cd-Sn, and $^{130}$Te-Xe are compared with available experimental data.

  13. Energy density functional study of nuclear matrix elements for neutrinoless $\\beta\\beta$ decay

    Rodríguez, Tomás R

    2010-01-01

    We present an extensive study of nuclear matrix elements (NME) for the neutrinoless double beta decay of the nuclei $^{48}$Ca, $^{76}$Ge, $^{82}$Se, $^{96}$Zr, $^{100}$Mo, $^{124}$Sn, $^{128}$Te, $^{130}$Te, $^{136}$Xe, and $^{150}$Nd based on state-of-the-art energy density functional methods using the Gogny D1S functional. Beyond mean-field effects are included within the generating coordinate method with particle number and angular momentum projection for both initial and final ground states. We obtain a rather constant value for the NME's around 4.7 with the exception of $^{48}$Ca and $^{150}$Nd, where smaller values are found. We analyze the role of deformation and pairing in the evaluation of the NME and present detailed results for the decay of $^{150}$Nd.

  14. Microscopic study of muon-capture transitions in nuclei involved in double-beta-decay processes

    Kortelainen, M

    2003-01-01

    Total and partial ordinary muon-capture (OMC) rates to 1 sup + and 2 sup - states are calculated in the framework of the proton-neutron quasiparticle random-phase approximation (pnQRPA) for several nuclei involved in double-beta-decay processes. The aim is to obtain information on intermediate states involved in double-beta-decay transitions having these nuclei as either daughter or parent nuclei. It is found that the OMC observables, just like the 2 nu beta beta-decay amplitudes, strongly depend on the particle-particle part of the proton-neutron interaction. First experiments measuring the partial OMC rates for nuclei involved in double beta decays have recently been performed.

  15. Sense and sensitivity of double beta decay experiments

    The search for neutrinoless double beta decay is a very active field in which the number of proposals for next-generation experiments has proliferated. In this paper we attempt to address both the sense and the sensitivity of such proposals. Sensitivity comes first, by means of proposing a simple and unambiguous statistical recipe to derive the sensitivity to a putative Majorana neutrino mass, mββ. In order to make sense of how the different experimental approaches compare, we apply this recipe to a selection of proposals, comparing the resulting sensitivities. We also propose a ''physics-motivated range'' (PMR) of the nuclear matrix elements as a unifying criterium between the different nuclear models. The expected performance of the proposals is parametrized in terms of only four numbers: energy resolution, background rate (per unit time, isotope mass and energy), detection efficiency, and ββ isotope mass. For each proposal, both a reference and an optimistic scenario for the experimental performance are studied. In the reference scenario we find that all the proposals will be able to partially explore the degenerate spectrum, without fully covering it, although four of them (KamLAND-Zen, CUORE, NEXT and EXO) will approach the 50 meV boundary. In the optimistic scenario, we find that CUORE and the xenon-based proposals (KamLAND-Zen, EXO and NEXT) will explore a significant fraction of the inverse hierarchy, with NEXT covering it almost fully. For the long term future, we argue that 136Xe-based experiments may provide the best case for a 1-ton scale experiment, given the potentially very low backgrounds achievable and the expected scalability to large isotope masses

  16. GERDA: a germanium detector array to search for neutrinoless double beta decay

    The GERDA, a new experiment to search for the double beta decay of 76Ge, is being installed at Laboratori Nazionali del Gran Sasso. The potentialities of this experiment as well the status of the project are reviewed

  17. First results of neutrinoless double beta decay search with the GERmanium Detector Array "GERDA"

    Janicskó Csáthy, József

    2014-06-01

    The study of neutrinoless double beta decay is the most powerful approach to the fundamental question if the neutrino is a Majorana particle, i.e. its own anti-particle. The observation of the lepton number violating neutrinoless double beta decay would establish the Majorana nature of the neutrino. Until now neutrinoless double beta decay was not observed. The GERmanium Detector Array, GERDA is a double beta decay experiment located at the INFN Gran Sasso National Laboratory, Italy. GERDA operates bare Ge diodes enriched in 76Ge in liquid argon supplemented by a water shield. The exposure accumulated adds up to 21.6 kg· yr with a background level of 1.8 · 10-2 cts/(keV·kg·yr). The results of the Phase I of the experiment are presented and the preparation of the Phase II is briefly discussed.

  18. Search for Neutrinoless Double-Beta Decay in $^{136}$Xe with EXO-200

    Auger, M; Barbeau, P S; Beauchamp, E; Belov, V; Benitez-Medina, C; Breidenbach, M; Brunner, T; Burenkov, A; Cleveland, B; Cook, S; Daniels, T; Danilov, M; Davis, C G; Delaquis, S; deVoe, R; Dobi, A; Dolinski, M J; 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, T N; Karelin, A; Kaufman, L J; Kuchenkov, A; Kumar, K S; Leonard, D S; Leonard, F; Mackay, D; MacLellan, R; Marino, M; Mong, B; Diez, M Montero; Muller, A R; Neilson, R; Nelson, R; Odian, A; Ostrovskiy, I; O'Sullivan, K; Ouellet, C; Piepke, A; Pocar, A; Prescott, C Y; Pushkin, K; Rowson, P C; Russell, J J; Sabourov, A; Sinclair, D; Slutsky, S; Stekhanov, V; Tolba, T; Tosi, D; Twelker, K; Vogel, P; Vuilleumier, J -L; Waite, A; Walton, T; Weber, M; Wichoski, U; Wodin, J; Wright, J D; Yang, L; Yen, Y -R; Zeldovich, O Ya

    2012-01-01

    We report on a search for neutrinoless double-beta decay of $^{136}$Xe with EXO-200. No signal is observed for an exposure of 32.5 kg-yr, with a background of ~1.5 x 10^{-3} /(kg yr keV) in the $\\pm 1\\sigma$ region of interest. This sets a lower limit on the half-life of the neutrinoless double-beta decay $T_{1/2}^{0\

  19. Light-neutrino masses and hierarchies and the observability of neutrinoless double-beta decay

    Civitarese, O

    2003-01-01

    Results for the neutrino mixing matrix U, obtained from the analysis of SNO, SK and CHOOZ, data, are used to calculate the effective neutrino mass relevant for the neutrinoless double beta decay.The best fit value of U yields an upper limit of 0.03 eV. The observability of the neutrinoless double beta decay is discussed within different neutrino mass hierarchies.

  20. What do we know about neutrinoless double-beta decay nuclear matrix elements?

    Menéndez, J

    2016-01-01

    The detection of neutrinoless double-beta decay will establish the Majorana nature of neutrinos. In addition, if the nuclear matrix elements of this process are reliably known, the experimental lifetime will provide precious information about the absolute neutrino masses and hierarchy. I review the status of nuclear structure calculations for neutrinoless double-beta decay matrix elements, and discuss some key issues to be addressed in order to meet the demand for accurate nuclear matrix elements.

  1. Probing New Physics Models of Neutrinoless Double Beta Decay with SuperNEMO

    Arnold, R; Baker, J; Barabash, A S; Basharina-Freshville, A; Bongrand, M; Brudanin, V; Caffrey, A J; Cebrián, S; Chapon, A; Chauveau, E; Dafni, Th; Deppisch, F F; Diaz, J; Durand, D; Egorov, V; Evans, J J; Flack, R; Fushima, K-I; Irastorza, I García; Garrido, X; Gómez, H; Guillon, B; Holin, A; Holy, K; Horkey, J J; Hubert, Ph; Hugon, C; Iguaz, F J; Ishihara, N; Jackson, C M; Jullian, S; Kauer, M; Kochetov, O; Konovalov, S I; Kovalenko, V; Lamhamdi, T; Lang, K; Lutter, G; Luzón, G; Mamedov, F; Marquet, Ch; Mauger, F; Monrabal, F; Nachab, A; Nasteva, I; Nemchenok, I; Nguyen, C H; Nomachi, M; Nova, F; Ohsumi, H; Pahlka, R B; Perrot, F; Piquemal, F; Povinec, P P; Richards, B; Ricol, J S; Riddle, C L; Rodríguez, A; Saakyan, R; Sarazin, X; Sedgbeer, J K; Serra, L; Shitov, Yu; Simard, L; Šimkovic, F; Söldner-Rembold, S; Štekl, I; Sutton, C S; Tamagawa, Y; Thomas, J; Timkin, V; Tretyak, V; Tretyak, Vl I; Umatov, V I; Vanyushin, I A; Vasiliev, R; Vasiliev, V; Vorobel, V; Waters, D; Yahlali, N; Žukauskas, A

    2010-01-01

    The possibility to probe new physics scenarios of light Majorana neutrino exchange and right-handed currents at the planned next generation neutrinoless double beta decay experiment SuperNEMO is discussed. Its ability to study different isotopes and track the outgoing electrons provides the means to discriminate different underlying mechanisms for the neutrinoless double beta decay by measuring the decay half-life and the electron angular and energy distributions.

  2. Neutrinoless double beta decay potential in a large mixing angle world

    Klapdor-Kleingrothaus, Hans Volker; Smirnov, Yu A

    2001-01-01

    We discuss the possibility of reconstructing the neutrino mass spectrum from the complementary processes of neutrino oscillations and double beta decay in view of the new data of Super-Kamiokande presented at the Neutrino2000 conference. Since the large mixing angle solution is favored, now, the prospects to observe double beta decay and provide informations on the absolute mass scale in the neutrino sector have been improved.

  3. Light neutrino contribution: is it all there is to neutrinoless double beta decay?

    Mahajan, Namit

    2015-01-01

    We consider perturbative one loop QCD corrections to the light neutrino contribution to neutrinoless double beta decay and find large enhancement to the rate. QCD corrections also generate structures which mimic new physics contributions usually considered. Within some approximations, the net effect seem to almost saturate the experimental limits, and therefore seems to implt that this is all there is to neutrinoless double beta decay.

  4. Consensus Report of a Workshop on "Matrix elements for Neutrinoless Double Beta Decay"

    Zuber, K.

    2005-01-01

    This is the consensus of a Workshop on "Matrix elements for Neutrinoless Double Beta Decay" held at the IPPP Durham (UK). The aim of this workshop has been to define a well planned, coherent strategy to reduce the errors on nuclear matrix element calculations for double beta decay to a level of 30% by performing the necessary measurements with currently existing and planned facilities. These measurements should provide reliable input for the theoretical calculations. The outcome of the worksh...

  5. Double beta decays of 100Mo by ELEGANT V at Oto Cosmo Observatory

    Exclusive measurements of neutrino-less double beta decays(0νββ) of 100Mo were made by means of ELEGANT V. The present status of the double beta decay experiment with ELEGANT V is presented. The data at Oto lab., being combined with the data at Kamioka, gives stringent limits on half-lives for 0νββ and < 1.7 eV

  6. Bonner Prize Talk -- First Laboratory Observation of Double Beta Decay

    Moe, Michael

    2013-04-01

    Although we are awash in neutrinos, we remain ignorant of some of their fundamental properties. We don't know their masses. We don't know whether ``anti-neutrinos'' are really distinct particles. Double beta (ββ) decay offers a handle on these questions if we can observe the energy spectrum of the two emitted electrons, and determine whether or not they share their energy with two neutrinos. Seeing neutrinoless (0ν) decay would solve some enduring puzzles. The power of the process to elucidate the neutrino was recognized in the 1930's, but ββ decay would be exceedingly rare and difficult to detect. Unsuccessful laboratory searches had been going on for 25 years when the UC Irvine group began its first experiment with a cloud chamber in 1972. After some background for the non-expert, and a snapshot of the theoretical and experimental milieu at the time, the talk will begin with the reasons for choosing a cloud chamber, and the taming of its balky and idiosyncratic behavior. The talk will end with the first definitive observation of two-neutrino (2ν)ββ decay of ^82Se in the vastly superior time projection chamber (TPC) in 1987. Discouragement through the tortuous 15-year interval was relieved by occasional victories. Some I will illustrate with revealing cloud-chamber photographs. We learned many things from this primitive device, and after seven years we isolated an apparent ββ decay signal. But the efficiency of the trigger was small, and difficult to pin down. Estimating 2.2%, we were way low. The resulting ``short'' ^82Se half-life of 1 x 10^19 years was suspect. New technology came to the rescue with the invention of the TPC. Experience with the cloud chamber guided our design of a TPC specifically for ββ decay. The TPC was built from scratch. Its long, steep learning curve was also punctuated with little triumphs. A memorable moment was the first turn-on of a portion of the chamber. So long ago, this all seems rather quaint, but through ample use of

  7. Measurement of double beta decay - experiments TGV and NEMO

    The group of experimentalists of FNSPE CTU Prague takes part in two experiments connected with double beta (ββ) decay - TGV and NEMO. Both experimental set-ups are placed in the Modane underground laboratory (France). Experiment TGV has two phases. TGV I is a measurement of ββ decay of 48Ca (β-β-) and TGV II is a measurement with 106Cd (EC/EC, β+β+, β+/EC). The design and performances of the TGV I apparatus have been already detailed elsewhere. Measurements of the ββ decay of 48Ca have been started in August of 1996. The processing of the experimental data (still in progress), covering almost one year exposition (8700 hours), led to the following value of the half-life of 2νββ of 48Ca, T1/2 (4.2-1.3+3.3) . 1019 years and to an estimate of a limit on the half-life of 0νββ of 48Ca, T1/2 > 1.5 . 1021 years (90% CL). The aim of the project TGV II is the measurement of ββ decay of 106Cd particularly 2νEC/EC mode. This decay, up to now not measured, is characterized by the emission of two X-rays with energy approx. 23 keV. Project should give also information on the other modes - β+β+, β+/EC and EC/EC accompanied by the emission of a Majoron. TGV II is based on new spectrometer consisting of 32 HPGe detectors similar to the TGV I spectrometer. The background measurement is now in progress. The start of measurement with 106Cd is planned from the end of 2000. FNSPE CTU also participates in NEMO collaboration. The goal of the experiment NEMO-3 is to be sensitive to a 0.1 eV Majorana neutrino mass by looking for the 0νββ process of 100Mo. Two prototypes NEMO-1 and NEMO-2 have been built. The NEMO-2 gave (after 6 years of data taking) physical results for 2νββdecay of 100Mo, 116Cd, 82Se and 96Zr. The installation of NEMO-3 detector started in the Modane underground laboratory and should be ready in summer 2000. (author)

  8. Realisation of a {beta} spectrometer solenoidal and a double {beta} spectrometer at coincidence; Realisation d'un spectrometre {beta} solenoidal et d'un double spectrometre {beta} a coincidence

    Moreau, J. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1955-06-15

    The two spectrometers have been achieved to tackle numerous problems of nuclear spectrometry. They possess different fields of application that complete themselves. The solenoidal spectrometer permits the determination of the energy limits of {beta} spectra and of their shape; it also permits the determination of the coefficients of internal conversion and reports {alpha}{sub K} / {alpha}{sub L} and it is especially efficient for the accurate energy levels of the {gamma} rays by photoelectric effect. The double coincidence spectrometer has been conceived to get a good efficiency in coincidence: indeed, the sum of the solid angles used for the {beta} and {gamma} emission is rather little lower to 4{pi} steradians. To get this efficiency, one should have sacrificed a little the resolution that is lower to the one obtained with the solenoidal spectrometer for a same brightness. Each of the elements of the double spectrometer can also be adapted to the study of angular correlations {beta}{gamma} and e{sup -}{gamma}. In this use, it is superior to the thin magnetic lens used up to here. The double spectrometer also permits the survey of the coincidences e{sup -}e{sup -}, e{sup -}{beta} of a equivalent way to a double lens; it can also be consider some adaptation for the survey of the angular correlations e{sup -}e{sup -}, e{sup -}{beta}. Finally, we applied the methods by simple spectrometry and by coincidence spectrometry, to the study of the radiances of the following radioelements: {sup 76}As (26 h), {sup 122}Sb (2,8 j), {sup 124}Sb (60 j), {sup 125}Sb (2,7 years). (M.B.) [French] Les deux spectrometres qui ont ete realises permettent d'aborder un grand nombre de problemes de spectrometrie nucleaire. Ils possedent des champs d'application tres differents qui se completent. Le spectrometre solenoidal permet la determination des energies limites des spectres {beta} et de leur forme; il permet aussi la determination des coefficients de conversion interne et

  9. Uncertainties in neutrinoless $\\beta \\beta $ decay transition matrix elements within mechanisms involving light Majorana neutrinos, classical Majorons and sterile neutrinos

    Rath, P K; Chaturvedi, K; Lohani, P; Raina, P K; Hirsch, J G

    2013-01-01

    In the PHFB model, uncertainties in the nuclear transition matrix elements for the neutrinoless double-$\\beta $ decay of $\\ ^{94,96}$Zr, $^{98,100}$Mo, $^{104}$Ru, $^{110}$Pd, $^{128,130}$Te and $^{150}$Nd isotopes within mechanisms involving light Majorana neutrinos, classical Majorons and sterile neutrinos are statistically estimated by considering sets of sixteen (twenty-four) matrix elements calculated with four different parametrization of the pairing plus multipolar type of effective two-body interaction, two sets of form factors and two (three) different parameterizations of Jastrow type of short range correlations. In the mechanisms involving the light Majorana neutrinos and classical Majorons, the maximum uncertainty is about 15% and in the scenario of sterile neutrinos, it varies in between approximately 4 (9)%--20 (36)% without(with) Jastrow short range correlations with Miller-Spencer parametrization, depending on the considered mass of the sterile neutrinos.

  10. The Majorana Demonstrator: A Search for Neutrinoless Double-beta Decay of 76Ge

    Xu, W; Avignone, F T; Barabash, A S; Bertrand, F E; Brudanin, V; Busch, M; Buuck, M; Byram, D; Caldwell, A S; Chan, Y-D; Christofferson, C D; Cuesta, C; Detwiler, J A; Efremenko, Yu; Ejiri, H; Elliott, S R; Galindo-Uribarri, A; Giovanetti, G K; Goett, J; Green, M P; Gruszko, J; Guinn, I; Guiseppe, V E; Henning, R; Hoppe, E W; Howard, S; Howe, M A; Jasinski, B R; Keeter, K J; Kidd, M F; Konovalov, S I; Kouzes, R T; LaFerriere, B D; Leon, J; MacMullin, J; Martin, R D; Meijer, S J; Mertens, S; Orrell, J L; O'Shaughnessy, C; Overman, N R; Poon, A W P; Radford, D C; Rager, J; Rielage, K; Robertson, R G H; Romero-Romero, E; Ronquest, M C; Shanks, B; Shirchenko, M; Snyder, N; Suriano, A M; Tedeschi, D; Trimble, J E; Varner, R L; Vasilyev, S; Vetter, K; Vorren, K; White, B R; Wilkerson, J F; Wiseman, C; Yakushev, E; Yu, C-H; Yumatov, V

    2015-01-01

    Neutrinoless double-beta decay is a hypothesized process where in some even-even nuclei it might be possible for two neutrons to simultaneously decay into two protons and two electrons without emitting neutrinos. This is possible only if neutrinos are Majorana particles, i.e. fermions that are their own antiparticles. Neutrinos being Majorana particles would explicitly violate lepton number conservation, and might play a role in the matter-antimatter asymmetry in the universe. The observation of neutrinoless double-beta decay would also provide complementary information related to neutrino masses. The Majorana Collaboration is constructing the Majorana Demonstrator, a 40-kg modular germanium detector array, to search for the Neutrinoless double-beta decay of 76Ge and to demonstrate a background rate at or below 3 counts/(ROI-t-y) in the 4 keV region of interest (ROI) around the 2039 keV Q-value for 76Ge Neutrinoless double-beta decay. In this paper, we discuss the physics of neutrinoless double beta decay and...

  11. Double-beta transition Q-value and direct mass measurements with TRIGA-TRAP

    Neutrinoless double-beta transitions are difficult to observe due to their long half-lives. In case of neutrinoless double-electron capture, a resonant enhancement of the decay rate by several orders of magnitude occurs if the energy levels of initial and final state are degenerate in energy. In order to search for nuclides undergoing a resonantly-enhanced double-electron capture the Q-values of the transitions in 106Cd, 108Cd, and 184Os were determined by the double-Penning trap mass spectrometer TRIGA-TRAP with a precision better than 1 keV. The double-beta decay Q-value of 110Pd was investigated as well. The recent results are presented.

  12. ZnWO_4 crystals as detectors for double beta decay and dark matter experiments

    Danevich, F A; Nagorny, S S; Poda, D V; Tretyak, V I; Yurchenko, S S; Zdesenko, Y G; Zdesenko, Yu.G.

    2004-01-01

    Energy resolution, alpha/beta ratio, and the pulse shape discrimination ability of the ZnWO_4 crystal scintillators were studied. The radioactive contamination of a ZnWO_4 crystal was investigated in the Solotvina Underground Laboratory. Possibilities to apply ZnWO_4 crystals for the dark matter and double beta decay searches are discussed. New improved half-life limits on double beta decay in zinc isotopes were established, in particular, for EC\\beta^+ decay of 64-Zn as: T_1/2^2nu > 8.9 10^18 yr and T_1/2^0nu > 3.6 10^18 yr, both at 68% CL.

  13. Double Beta Decay Experiments: Present Status and Prospects for the Future

    Barabash, A. S.

    The review of modern experiments on search and studying of double beta decay processes is done. Results of the most sensitive current experiments are discussed. The main attention is paid to EXO-200, KamLAND-Zen, GERDA-I and CUORE-0 experiments. Modern values of T1/2(2ν) and best present limits on neutrinoless double beta decay and double beta decay with Majoron emission are presented. Conservative limits on effective mass of a Majorana neutrino ( at the level of ∼ (0.01-0.1) eV are discussed. The main attention is paid to experiments of CUORE, GERDA, MAJORANA, EXO, KamLAND-Zen-2, SuperNEMO and SNO+. Possibilities of low-temperature scintillating bolometers on the basis of inorganic crystals (ZnSe, ZnMoO4, Li2MoO4, CaMoO4 and CdWO4) are considered too.

  14. First results of the search of neutrinoless double beta decay with the NEMO 3 detector

    Arnold, R; Baker, J; Barabash, A; Broudin, G; Brudanin, V; Caffrey, A J; Caurier, E; Egorov, V; Errahmane, K; Etienvre, A I; Guyonnet, J L; Hubert, F; Hubert, P; Jollet, C; Jullian, S; Kochetov, O; Kovalenko, V; Konovalov, S; Lalanne, D; Leccia, F; Longuemare, C; Lutter, G; Marquet, C; Mauger, F; Nowacki, F; Ohsumi, H; Piquemal, F; Reyss, J L; Saakyan, R; Sarazin, X; Simard, L; Simkovic, F; Shitov, Y; Smolnikov, A A; Stekl, I; Suhonen, J; Sutton, C S; Szklarz, G; Thomas, J; Timkin, V; Tretyak, V; Umatov, V; Vàla, L; Vanyushin, I A; Vasilyev, V; Vorobel, V; Vylov, T D

    2005-01-01

    The NEMO 3 detector, which has been operating in the Frejus underground laboratory since February 2003, is devoted to the search for neutrinoless double beta decay (bb0nu). Half-lives of the two neutrino double beta decays (bb2nu) have been measured for 100Mo and 82Se. After 389 effective days of data collection from February 2003 until September 2004 (Phase I), no evidence for neutrinoless double beta decay was found from ~7kg of 100Mo and ~1 kg of 82Se. The corresponding lower limits for the half-lives are 4.6 x 10^23 years for 100Mo and 1.0 x10^23 years for 82Se (90% C.L.). Depending on the nuclear matrix elements calculation, limits for the effective Majorana neutrino mass are < 1.7-4.9 eV for 82Se

  15. The MAJORANA DEMONSTRATOR: A Search for Neutrinoless Double-beta Decay of Germanium-76

    Schubert, A G; Avignone, F T; Back, H O; Barabash, A S; Bergevin, M; Bertrand, F E; Boswell, M; Brudanin, V; Busch, M; Chan, Y-D; Christofferson, C D; Collar, J I; Combs, D C; Cooper, R J; Detwiler, J A; Leon, J; Doe, P J; Efremenko, Yu; Egorov, V; Ejiri, H; Elliott, S R; Esterline, J; Fast, J E; Fields, N; Finnerty, P; Fraenkle, F M; Gehman, V M; Giovanetti, G K; Green, M P; Guiseppe, V E; Gusey, K; Hallin, A L; Hazama, R; Henning, R; Hime, A; Hoppe, E W; Horton, M; Howard, S; Howe, M A; Johnson, R A; Keeter, K J; Keillor, M E; Keller, C; Kephart, J D; Kidd, M F; Knecht, A; Kochetov, O; Konovalov, S I; Kouzes, R T; LaFerriere, B; LaRoque, B H; Leviner, L E; Loach, J C; MacMullin, S; Marino, M G; Martin, R D; Mei, D -M; Merriman, J; Miller, M L; Mizouni, L; Nomachi, M; Orrell, J L; Overman, N; Phillips, D G; Poon, A W P; Perumpilly, G; Prior, G; Radford, D C; Rielage, K; Robertson, R G H; Ronquest, M C; Shima, T; Shirchenko, M; Snavely, K J; Sobolev, V; Steele, D; Strain, J; Thomas, K; Timkin, V; Tornow, W; Vanyushin, I; Varner, R L; Vetter, K; Vorren, K; Wilkerson, J F; Wolfe, B A; Yakushev, E; Young, A R; Yu, C ?H; Yumatov, V; Zhan, C

    2011-01-01

    The observation of neutrinoless double-beta decay would determine whether the neutrino is a Majorana particle and provide information on the absolute scale of neutrino mass. The MAJORANA Collaboration is constructing the DEMONSTRATOR, an array of germanium detectors, to search for neutrinoless double-beta decay of 76-Ge. The DEMONSTRATOR will contain 40 kg of germanium; up to 30 kg will be enriched to 86% in 76-Ge. The DEMONSTRATOR will be deployed deep underground in an ultra-low-background shielded environment. Operation of the DEMONSTRATOR aims to determine whether a future tonne-scale germanium experiment can achieve a background goal of one count per tonne-year in a 4-keV region of interest around the 76-Ge neutrinoless double-beta decay Q-value of 2039 keV.

  16. Experimental study of double beta decay modes using a CdZnTe detector array

    Dawson, J V; Janutta, B; Junker, M; Koettig, T; Münstermann, D; Rajek, S; Reeve, C; Schulz, O; Wilson, J R; Zuber, K

    2009-01-01

    An array of sixteen 1 cm^3 CdZnTe semiconductor detectors was operated at the Gran Sasso Underground Laboratory (LNGS) to further investigate the feasibility of double beta decay searches with such devices. As one of the double beta decay experiments with the highest granularity the 4 x 4 array accumulated an overall exposure of 18 kg days. The set-up and performance of the array is described. Half-life limits for various double beta decay modes of Cd, Zn and Te isotopes are obtained. No signal has been found, but several limits beyond 10^20 years have been performed. They are an order of magnitude better than those obtained with this technology before and comparable to most other experimental approaches for the isotopes under investigation.

  17. Experiments TGV I (double-beta decay of 48Ca) and TGV II (double-beta decay of 106Cd and 48Ca)

    Štekl, I.; Čermák, P.; Beneš, P.; Brudanin, V. B.; Rukhadze, N. I.; Egorov, V. G.; Kovalenko, V. E.; Kovalík, A.; Salamatin, A. V.; Tsoupko-Sitnikov, V. V.; Vylov, Ts.; Briancon, Ch.; Šimkovic, F.

    2000-04-01

    Present status of experiments TGV I and TGV II is given. The TGV I collaboration has studied the double-beta decay of 48Ca with a low-background and high sensitivity Ge multi-detector spectrometer TGV (Telescope Germanium Vertical). The preliminary results of years and years (90% CL) for double-beta decay of 48 Ca has been found after the processing of experimental data obtained after 8700 hours of measuring time using approximately 1 gramme of 48Ca. The aim of the experiment TGV II is the development of the experimental methods, construction of spectrometers and measurement of the decay (++, β+/EC, EC/EC) of 106Cd particularly the 2νEC/EC mode. The theoretical description and performance of the TGV II spectrometer are also given.

  18. Is the non observation of neutrinoless double beta decay a question of sensitivity?

    The hypothetical neutrinoless double beta decay is possible only if the neutrino is a truly neutral particle and if it is massive. A truly neutral particle (e.g. a particle identical with its antiparticle) should have all its algebraic intrinsic properties equal to zero, in particular, its lepton number should be 0. Now, since the neutrino is a lepton, its lepton number should be 1. This contradiction would lead to conclude that neutrinoless double beta decay could not take place in nature. This conclusion is, up to now, in agreement with persistent failures to put this long sought hypothetical key decay into evidence despite huge efforts dedicated to this aim

  19. Is the non-observation of neutrinoless double beta decay a question of sensitivity?

    Hypothetical neutrinoless double beta decay is possible only if the neutrino is a truly neutral particle and if it is massive. A truly neutral particle (e.g. a particle identical with its antiparticle) should have all its algebraic intrinsic properties equal to zero, in particular, its lepton number should be 0. Now, since the neutrino is a lepton, its lepton number should be 1. This contradiction would lead one to conclude that neutrinoless double beta decay cannot take place in nature. This conclusion is, up to now, in agreement with persistent failures to find evidence for this long sought key hypothetical decay despite huge efforts dedicated to this aim. (author)

  20. Double beta decays and fundamental laws studied by ultra rare-decay nuclear spectroscopy

    Recent works on double beta decays and on fundamental laws, which are studied by means of the ultra rare-decay nuclear spectroscopy, are described. Subjects discussed here include unique features of the nuclear spectroscopic method for studying basic problems of nuclear and particle interactions, neutrinos and weak interactions studied by double-beta and gamma spectroscopy, weakly interacting dark matters studied by nuclear recoil spectroscopy, exotic K X-ray transitions and charge non-conservation, and exotic nuclear transitions associated with nucleon decays. (author)

  1. Double-beta decay of 48Ca in the TGV experiment

    The low-background, high-sensitivity Ge multidetector spectrometer TGV is used to study the double-beta decay of 48Ca. Additional suppression of the recorded background is achieved with neutron shielding and a method for distinguishing β particles from γ rays by detector-pulse rise time. The estimates T1sol2ββ2v= (4.2 ± 2.4) x 1019 yr and T1sol2ββ0v > 1.5 x 1021 yr (at a 90% C.L.) for the double-beta decay of 48Ca are obtained

  2. Search for double beta decay of 48Ca in the TGV experiment

    Brudanin, V. B.; Rukhadze, N. I.; Briançon, C.; Egorov, V. G.; Kovalenko, V. E.; Kovalik, A.; Salamatin, A. V.; Štekl, I.; Tsoupko-Sitnikov, V. V.; Vylov, T.; Čermák, P.

    2000-12-01

    This Letter describes a collaborative TGV (Telescope Germanium Vertical) study of the double beta decay of 48Ca with a low-background and high sensitivity Ge multi-detector spectrometer. The results of T1/22νββ=(4.2+3.3- 1.3)×1019 years and T1/20νββ>1.5×1021 years (90% CL) for double beta decay of 48Ca were found after processing experimental data obtained after 8700 hours of measuring time, using approximately 1 gramme of 48Ca. The features of a TGV-2 experiment are also presented.

  3. Double-beta decay of 48Ca in the TGV experiment

    The low-background, high-sensitivity Ge multi-detector spectrometer TVG was used to study the double-beta decay of 48Ca. Additional suppression of the registered background was achieved with a neutron shielding and a method of distinguishing β-particles from γ-rays by detector pulse rise time. The estimates T1/2ββ2ν = (4.2 ±2.4) x 1019 yr and T1/2ββ0ν > 1.5 x 1021 yr (90% C.L.) for the double-beta decay of 48Ca were obtained

  4. Observation of Two-Neutrino Double-Beta Decay in Xe-136 with EXO-200

    Ackerman, N.; /SLAC; Aharmim, B.; /Laurentian U.; Auger, M.; /Bern U.; Auty, D.J.; /Alabama U.; Barbeau, P.S.; Barry, K.; Bartoszek, L.; /Stanford U., Phys. Dept.; Beauchamp, E.; /Laurentian U.; Belov, V.; /Moscow, ITEP; Benitez-Medina, C.; /Colorado State U.; Breidenbach, M.; /SLAC; Burenkov, A.; /Moscow, ITEP; Cleveland, B.; /Laurentian U.; Conley, R.; Conti, E.; /SLAC; Cook, J.; /Massachusetts U., Amherst; Cook, S.; /Colorado State U.; Coppens, A.; /Carleton U.; Counts, I.; /Stanford U., Phys. Dept.; Craddock, W.; /SLAC; Daniels, T.; /Massachusetts U., Amherst /Moscow, ITEP /Maryland U. /Stanford U., Phys. Dept. /Alabama U. /Maryland U. /Moscow, ITEP /Stanford U., Phys. Dept. /Laurentian U. /Carleton U. /Colorado State U. /Laurentian U. /Munich, Tech. U. /Bern U. /SLAC /Bern U. /Carleton U. /Stanford U., Phys. Dept. /Carleton U. /Maryland U. /Colorado State U. /SLAC /Carleton U. /SLAC /Alabama U. /SLAC /Moscow, ITEP /Indiana U. /Stanford U., Phys. Dept. /Moscow, ITEP /Stanford U., Phys. Dept. /Massachusetts U., Amherst /Seoul U. /Carleton U. /Stanford U., Phys. Dept.; /more authors..

    2012-09-14

    We report the observation of two-neutrino double-beta decay in {sup 136}Xe with T{sub 1/2} = 2.11 {+-} 0.04(stat) {+-} 0.21(syst) x 10{sup 21} yr. This second-order process, predicted by the standard model, has been observed for several nuclei but not for {sup 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.

  5. New limit on the neutrinoless double beta decay of 100Mo

    A search for the neutrinoless double beta decay of 100Mo was conducted using thin Mo films and solid state Si detectors. The experiment has collected 3500 hours of data operating underground in a deep silver mine (3290 M.W.E.). Only one event was found to be consistent with neutrinoless double beta decay. Using this one event, a limit of ≥ 1 x 1022 years (1 σ) is set on the 100Mo half-life. This is approximately five times larger than the best previous 100Mo limit

  6. Simulation studies for Tin Bolometer Array for Neutrinoless Double Beta Decay

    Singh, V; Mathimalar, S; Nanal, V; Pillay, R G

    2014-01-01

    It is important to identify and reduce the gamma radiation which can be a significant source of background for any double beta decay experiment. The TIN.TIN detector array, which is under development for the search of Neutrinoless Double Beta Decay in $^{124}$Sn, has the potential to utilize the hit multiplicity information to discriminate the gamma background from the events of interest. Monte Carlo simulations for optimizing the design of a Tin detector module has been performed by varying element sizes with an emphasis on the gamma background reduction capabilities of the detector array.

  7. Double beta decay: introduction, motivations and last results

    The double β decay process is the direct desexcitation from a nucleus (Z,A) to a nucleus (Z+2, A). Since long time ago, study of this process has been recognized as a very sensitive test of the lepton number non-conservation and therefore the double β decay process is strongly connected to the neutrino properties. This review starts with the main definitions and main motivations for such studies. Then the different experiments actually running and the most recent experimental results are exposed

  8. Neutrinoless double beta decay experiment DCBA using a magnetic momentum-analyzer

    Ishihara, N., E-mail: nobuhiro.ishihara@kek.jp [High Energy Accelerator Research Organization (KEK), Tsukuba, 305-0801 (Japan); Kato, Y.; Inagaki, T.; Ohama, T.; Takeda, S.; Yamada, Y. [High Energy Accelerator Research Organization (KEK), Tsukuba, 305-0801 Japan (Japan); Ukishima, N.; Teramoto, Y. [Osaka City University, Sumiyoshi, Osaka, 558-8585 (Japan); Morishima, Y.; Nakano, I. [Okayama University, Okayama, 700-8530 (Japan); Kitamura, S. [Tokyo Metropolitan University, Arakawa, Tokyo, 116-8551 (Japan); Sakamoto, Y. [Tohoku Gakuin University, Izumi, Sendai, 981-3193 (Japan); Nagasaka, Y. [Hiroshima Institute of Technology, Saeki, Hiroshima, 731-5193 (Japan); Tamura, N. [Niigata University, Niigata, 950-2181 (Japan); Tanaka, K. [BTE, Minato, Tokyo, 105-0011 (Japan); Ito, R. [ZTJ, Chiyoda, Tokyo, 101-0047 (Japan)

    2011-12-15

    A magnetic momentum-analyzer is being developed at KEK for neutrinoless double beta decay experiment called DCBA (Drift Chamber Beta-ray Analyzer, inverted ABCD). A lot of thin plates of {sup 150}Nd compound are installed in tracking detectors located in a uniform magnetic field. The three-dimensional position information is obtained for the helical track of a beta ray. More R and D will be studied using the second test apparatus DCBA-T2, which is now under construction.

  9. The search for Majorana neutrinos with neutrinoless double beta decays: From CUORICINO to LUCIFER experiment

    Bellini, F. [Dipartimento di Fisica, Sapienza Universita di Roma, Roma I-00185 (Italy) and INFN - Sezione di Roma, Roma I-00185 (Italy)

    2012-11-20

    The study of neutrino properties is one of the fundamental challenges in particle physics nowadays. Fifty years of investigations established that neutrinos are massive but the absolute mass scale has not yet been measured. Moreover its true nature is still unknown. Is the neutrino its own antiparticle (thus violating the lepton number) as proposed by Majorana in 1937? The only way to probe the neutrino nature is through the observation of Neutrinoless Double Beta Decay (0{nu}{beta}{beta}), a very rare spontaneous nuclear transition which emits two electrons and no neutrinos. In this paper, after a brief introduction to the theoretical framework of Majorana's neutrino, a presentation of experimental challenges posed by 0{nu}{beta}{beta} search will be given as well as an overview of present status and future perpectives of experiments.

  10. High efficiency beta-decay spectroscopy using a planar germanium double-sided strip detector

    Beta-decay spectroscopy experiments are limited by the detection efficiency of ions and electrons in the experimental setup. While there is a variety of different experimental setups in use for beta-decay spectroscopy, one popular choice is silicon double-sided strip detectors (DSSD). The higher Z of Ge and greater availability of thicker detectors as compared to Si potentially offer dramatic increases in the detection efficiency for beta-decay electrons. In this work, a planar GeDSSD has been commissioned for use in beta-decay spectroscopy experiments at the National Superconducting Cyclotron Laboratory (NSCL). The implantation response of the detector and its beta-decay detection efficiency is discussed. -- Highlights: • A planar Ge double-sided strip detector is implemented for decay spectroscopy. • Dual range preamplifiers provide sensitivity to both heavy ions and beta-decay electrons. • Beta-decay electron detection efficiencies greater than 50% are demonstrated. • Based on comparisons with simulation, an efficiency of roughly 90% is expected

  11. A first search of excited states double beta and double electron capture decays of Pd110 and Pd102

    Lehnert, Bjoern

    2011-01-01

    A search for double beta decays of the palladium isotopes Pd110 and Pd102 into excited states of their daughters was performed. New half-life limits for the 2nubb and 0nubb decays into first excited 0+ and 2+ states of 2.54e19 yr and 2.14e19 yr (95% CL) for the Pd110 decay were obtained improving limits by two orders of magnitude. The corresponding half-lives for double electron capture transition of Pd102 are 1.73e18 yr and 2.54e18 yr (95% CL) respectively. These are the first measurements for Pd102.

  12. A first search of excited states double beta and double electron capture decays of 110Pd and 102Pd

    A search for double beta decays of the palladium isotopes 110Pd and 102Pd into excited states of their daughters was performed and first half-life limits for the 2νββ and 0νββ decays into first excited 0+ and 2+ states of 5.89x1019 yr and 4.40x1019 yr (95% CL) for the 110Pd decay were obtained. The half-life limits for the corresponding double electron capture transition of 102Pd are 7.64x1018 yr and 2.68x1018 yr (95% CL) respectively. These are the first measurements for 102Pd.

  13. New concepts for a gaseous Xenon detector for double beta decay

    Xenon gas is an attractive medium for the search for neutrinoless double beta decay because it offers the possibility of reasonable energy resolution, event topology reconstruction, very high intrinsic purity and background rejection through the identification of the daughter barium ion. This talk explores recent developments in the conceptual design of such a detector.

  14. Measurement of double beta decay of 100Mo to excited states in the NEMO 3 experiment

    The double beta decay of 100Mo to the 01+ and 21+ excited states of 100Ru is studied using the NEMO 3 data. After the analysis of 8024 h of data the half-life for the two-neutrino double beta decay of 100Mo to the excited 01+ state is measured to be T1/2(2ν)=[5.7-0.9+1.3(stat.)+/-0.8(syst.)]x1020 y. The signal-to-background ratio is equal to 3. Information about energy and angular distributions of emitted electrons is also obtained. No evidence for neutrinoless double beta decay to the excited 01+ state has been found. The corresponding half-life limit is T1/2(0ν)(0+->01+)>8.9x1022 y (at 90% C.L.). The search for the double beta decay to the 21+ excited state has allowed the determination of limits on the half-life for the two neutrino mode T1/2(2ν)(0+->21+)>1.1x1021 y (at 90% C.L.) and for the neutrinoless mode T1/2(0ν)(0+->21+)>1.6x1023 y (at 90% C.L.)

  15. The status of the IGEX 76Ge double-beta decay experiment in 1997

    The International Germanium Experiment (IGEX) has six detectors containing ∼ 90 fiducial moles of 76Ge. Data from 74.84 fiducial mole years yield a lower bound T0ν1/2>0.8x1025 y for neutrinoless double-beta decay of 76Ge

  16. Status of double beta decay experiments using isotopes other than Xe-136

    Pandola, Luciano

    2014-01-01

    Neutrinoless double beta decay is a lepton-number violating process predicted by many extensions of the standard model. It is actively searched for in several candidate isotopes within many experimental projects. The status of the experimental initiatives which are looking for the neutrinoless double beta decay in isotopes other than Xe-136 is reviewed, with special emphasis given to the projects that passed the R&D phase. The results recently released by the experiment GERDA are also summarized and discussed. The GERDA data give no positive indication of neutrinoless double beta decay of Ge-76 and disfavor in a model-independent way the long-standing observation claim on the same isotope. The lower limit reported by GERDA for the half-life of neutrinoless double beta decay of Ge-76 is T1/2 > 2.1e25 yr (90% C.L.), or T1/2 > 3.0e25 yr, when combined with the results of other Ge-76 predecessor experiments.

  17. Neutrinoless Double Beta Decay in Type I+II Seesaw Models

    Borah, Debasish

    2015-01-01

    We study neutrinoless double beta decay in left-right symmetric extension of the standard model with type I and type II seesaw origin of neutrino masses. Due to the enhanced gauge symmetry as well as extended scalar sector, there are several new physics sources of neutrinoless double beta decay in this model. Ignoring the left-right gauge boson mixing and heavy-light neutrino mixing, we first compute the contributions to neutrinoless double beta decay for type I and type II dominant seesaw separately and compare with the standard light neutrino contributions. We then repeat the exercise by considering the presence of both type I and type II seesaw, having non-negligible contributions to light neutrino masses and show the difference in results from individual seesaw cases. Assuming the new gauge bosons and scalars to be around a TeV, we constrain different parameters of the model including both heavy and light neutrino masses from the requirement of keeping the neutrinoless double beta decay amplitude below th...

  18. Systematic Law for Half-lives of Double $\\beta$-decay with Two Neutrinos

    Ren, Yuejiao

    2014-01-01

    Nuclear double $\\beta$-decay with two neutrinos is a rare and important process for natural radioactivity of unstable nuclei. The experimental data of nuclear double $\\beta^{-}$-decay with two neutrinos are analyzed and a systematic law to calculate the half-lives of this rare process is proposed. It is the first analytical and simple formula for double $\\beta$-decay half-lives where the leading effect from both the Coulomb potential and nuclear structure is included. The systematic law shows that the logarithms of the half-lives are inversely proportional to the decay energies for the ground state transitions between parent nuclei and daughter nuclei. The calculated half-lives are in agreement with the experimental data of all known eleven nuclei with an average factor of 3.06. The half-lives of other possible double $\\beta$-decay candidates with two neutrinos are predicted and these can be useful for future experiments. The law, without introducing any extra adjustment, is also generalized to the calculatio...

  19. Measurement of double beta decay of 100Mo to excited states in the NEMO 3 experiment

    Arnold, R; Baker, J; Barabash, A S; Bongrand, M; Broudin, G; Brudanin, V; Caffrey, A J; Egorov, V; Etienvre, A I; Fatemi-Ghomi, N; Hubert, F; Hubert, P; Jerie, J; Jollet, C; Jullian, S; King, S; Kochetov, O; Konovalov, S I; Kovalenko, V; Lalanne, D; Lamhamdi, T; Leccia, F; Lemière, Y; Longuemare, C; Lutter, G; Marquet, C; Mauger, F; Nachab, A; Ohsumi, H; Perrot, F; Piquemal, F; Reyss, J L; Ricol, J S; Saakyan, R; Sarazin, X; Shitov, Y; Simard, L; Simkovic, F; Smolnikov, A; Stekl, I; Suhonen, J; Sutton, C S; Szklarz, G; Söldner-Rembold, S; Thomas, J; Timkin, V; Tretyak, V; Umatov, V; Vanyushin, I A; Vasilev, V; Vorobel, V; Vylov, T; Vàla, L; Hubert, Ph.; Marquet, Ch.; Shitov, Yu.; Vylov, Ts.

    2007-01-01

    The double beta decay of 100Mo to the 0^+_1 and 2^+_1 excited states of 100Ru is studied using the NEMO 3 data. After the analysis of 8024 h of data the half-life for the two-neutrino double beta decay of 100Mo to the excited 0^+_1 state is measured to be T^(2nu)_1/2 = [5.7^{+1.3}_{-0.9}(stat)+/-0.8(syst)]x 10^20 y. The signal-to-background ratio is equal to 3. Information about energy and angular distributions of emitted electrons is also obtained. No evidence for neutrinoless double beta decay to the excited 0^+_1 state has been found. The corresponding half-life limit is T^(0nu)_1/2(0^+ --> 0^+_1) > 8.9 x 10^22 y (at 90% C.L.). The search for the double beta decay to the 2^+_1 excited state has allowed the determination of limits on the half-life for the two neutrino mode T^(2nu)_1/2(0^+ --> 2^+_1) > 1.1 x 10^21 y (at 90% C.L.) and for the neutrinoless mode T^(0nu)_1/2(0^+ --> 2^+_1) > 1.6 x 10^23 y (at 90% C.L.).

  20. Neutrino Decay and Neutrinoless Double Beta Decay in a 3-3-1 Model

    Dias, Alex G.; Doff, A.(Universidade Tecnológica Federal do Paraná – UTFPR – DAFIS, Av. Monteiro Lobato Km 04, 84016-210 Ponta Grossa, PR, Brazil); Pires, C. A. de S.; da Silva, P. S. Rodrigues

    2005-01-01

    In this work we show that the implementation of spontaneous breaking of the lepton number in the 3-3-1 model with right-handed neutrinos gives rise to fast neutrino decay with majoron emission and generates a bunch of new contributions to the neutrinoless double beta decay.

  1. New physics in the new millennium with GENIUS: double beta decay, dark matter, solar neutrinos

    Double beta decay is indispensable to solve the question of the neutrino mass matrix together with ν oscillation experiments. The most sensitive experiment since eight years - the HEIDELBERG - MOSCOW experiment in Gran Sasso - already now, with the experimental limit of ν> 7Be) solar neutrinos. A GENIUS Test Facility has just been funded and will come into operation by the end of 2001

  2. Double Beta Decays into Excited States in $^{110}$Pd and $^{102}$Pd

    Lehnert, B; Degering, D; Hult, M; Laubenstein, M; Wester, T; Zuber, K

    2016-01-01

    A search for double beta decays of $^{110}$Pd and $^{102}$Pd into excited states of the daughter nuclides has been performed using three ultra-low background gamma-spectrometry measurements in the Felsenkeller laboratory, Germany, the HADES laboratory, Belgium and at the LNGS, Italy. The combined Bayesian analysis of the three measurements sets improved half-life limits for the $2\

  3. Measurement of the background in the NEMO 3 double beta decay experiment

    Argyriades, J; Augier, C; Baker, J; Barabash, A S; Bongrand, M; Broudin-Bay, G; Brudanin, V B; Caffrey, A J; Chapon, A; Chauveau, E; Daraktchieva, Z; Durand, D; Egorov, V G; Fatemi-Ghomi, N; Flack, R; Freshville, A; Guillon, B; Hubert, Ph; Jullian, S; Kauer, M; King, S; Kochetov, O I; Konovalov, S I; Kovalenko, V E; Lalanne, D; Lang, K; Lemi`ere, Y; Lutter, G; Mamedov, F; Marquet, Ch; Martín-Albo, J; Mauger, F; Nachab, A; Nasteva, I; Nemchenok, I B; Nova, F; Novella, P; Ohsumi, H; Pahlka, R B; Perrot, F; Piquemal, F; Reyss, J L; Ricol, J S; Saakyan, R; Sarazin, X; Simard, L; Shitov, Yu A; Smolnikov, A A; Snow, S; Söldner-Rembold, S; Stekl, I; Sutton, C S; Szklarz, G; Thomas, J; Timkin, V V; Tretyak, V I; Tretyak, Vl I; Umatov, V I; Vàla, L; Vanyushin, I A; Vasiliev, V A; Vorobel, V; Vylov, Ts

    2009-01-01

    In the double beta decay experiment NEMO~3 a precise knowledge of the background in the signal region is of outstanding importance. This article presents the methods used in NEMO~3 to evaluate the backgrounds resulting from most if not all possible origins. It also illustrates the power of the combined tracking-calorimetry technique used in the experiment.

  4. Inverse neutrinoless double $\\beta$ decay and other $\\Delta$ L=2 processes

    London, D

    1999-01-01

    I review the prospects for the detection of Delta L=2 processes at future colliders. Except in contrived models, the process e- e- -> W- W- is unobservable at future linear colliders unless $\\sqrt{s} \\gsim 2$ TeV, due to constraints from neutrinoless double beta decay. As there are no analogous constraints on the Majorana mass of the $\

  5. New concepts for a gaseous Xenon detector for double beta decay

    Sinclair, D.; Exo Collaboration

    2010-01-01

    Xenon gas is an attractive medium for the search for neutrinoless double beta decay because it offers the possibility of reasonable energy resolution, event topology reconstruction, very high intrinsic purity and background rejection through the identification of the daughter barium ion. This talk explores recent developments in the conceptual design of such a detector.

  6. Experiment TGV-2 - Search for double beta decay of 106Cd

    Rukhadze, N. I.; Briançon, Ch.; Brudanin, V. B.; Čermák, P.; Egorov, V. G.; Klimenko, A. A.; Kovalík, A.; Rukhadze, E. N.; Shitov, Yu. A.; Šimkovic, F.; Štekl, I.; Timkin, V. V.

    2012-08-01

    New limits (at 90% C.L.) on double beta decay of Cd106-T(0νEC/EC)>1.7×1020 yr and T(2νEC/EC)>4.2×1020 yr were obtained in a preliminary calculation of data accumulated for 12900 h on the TGV-2 spectrometer.

  7. Present status and future of the experiment TGV (measurement of double beta decay of48Ca)

    Brudanin, V. B.; Egorov, V. G.; Kovalík, A.; Kovalenko, V. E.; Rukhadze, N. I.; Salamatin, A. V.; Sandukovsky, V. G.; Timkin, V. V.; Vylov, Ts.; Zaparov, Ch.; Briancon, Ch.; Janout, Z.; Koníček, J.; Kubašta, J.; Pospíšil, S.; Štekl, I.; Vorobel, V.

    1998-02-01

    A short description of experiment TGV (double beta decay of48Ca) is given. The measurement started in the Modane underground laboratory in August 1996. The first result of T {1/2/0 ν } ≥ 4.6 × 1020 years [90% CL] after 2545 hours is presented.

  8. Present status and future of the experiment TGV (measurement of double beta decay of 48Ca)

    A short description of experiment TGV (double beta decay of 48Ca) is given. The measurement started in the Modane underground laboratory in August 1996. The first result of T1/20ν ≥ 4.6 x 1020 years [90% CL] after 2545 hours is presented. (author)

  9. Experiment TGV-2 – Search for double beta decay of 106Cd

    New limits (at 90% C.L.) on double beta decay of 106Cd−T1/2(0νEC/EC)>1.7×1020yr and T1/2(2νEC/EC)>4.2×1020yr were obtained in a preliminary calculation of data accumulated for 12900 h on the TGV-2 spectrometer.

  10. Spectral distribution Method for neutrinoless double beta decay: Results for $^{82}$Se and $^{76}$Ge

    Kota, V K B

    2016-01-01

    Statistical spectral distribution method based on shell model and random matrix theory is developed for calculating neutrinoless double beta decay nuclear transition matrix elements. First results obtained for $^{82}$Se and $^{76}$Ge using the spectral method are close to the available shell model results.

  11. Neutrinoless double beta decay in type I+II seesaw models

    Borah, Debasish; Dasgupta, Arnab

    2015-11-01

    We study neutrinoless double beta decay in left-right symmetric extension of the standard model with type I and type II seesaw origin of neutrino masses. Due to the enhanced gauge symmetry as well as extended scalar sector, there are several new physics sources of neutrinoless double beta decay in this model. Ignoring the left-right gauge boson mixing and heavy-light neutrino mixing, we first compute the contributions to neutrinoless double beta decay for type I and type II dominant seesaw separately and compare with the standard light neutrino contributions. We then repeat the exercise by considering the presence of both type I and type II seesaw, having non-negligible contributions to light neutrino masses and show the difference in results from individual seesaw cases. Assuming the new gauge bosons and scalars to be around a TeV, we constrain different parameters of the model including both heavy and light neutrino masses from the requirement of keeping the new physics contribution to neutrinoless double beta decay amplitude below the upper limit set by the GERDA experiment and also satisfying bounds from lepton flavor violation, cosmology and colliders.

  12. Limits on the neutrino mass from neutrinoless double-$\\beta $ decay

    Barea, J; Iachello, F

    2015-01-01

    Neutrinoless double-$\\beta$ decay is of fundamental importance for the determining neutrino mass. By combining a calculation of nuclear matrix elements within the framework of the microscopic interacting boson model (IBM-2) with an improved calculation of phase space factors, we set limits on the average light neutrino mass and on the average inverse heavy neutrino mass (flavor violating parameter).

  13. Measurement of the background in the NEMO 3 double beta decay experiment

    In the double beta decay experiment NEMO 3 a precise knowledge of the background in the signal region is of outstanding importance. This article presents the methods used in NEMO 3 to evaluate the backgrounds resulting from most if not all possible origins. It also illustrates the power of the combined tracking-calorimetry technique used in the experiment.

  14. Status of the Frejus experiment on the neutrinoless double beta decay of the 76Ge

    A brief account of the design, experimental set up and status of the Frejus experiments on the neutrinoless double beta decay of 76Ge is presented. The theoretical implications and expectatives of this experimental research are analized. A comparison with other dedicated experiments is also reported. (author)

  15. Investigation of the Majoron-accompanied double-beta decay mode of [sup 76]Ge

    Beck, M.; Bensch, F.; Bockholt, J.; Heusser, G.; Hirsch, M.; Klapdor-Kleingrothaus, H.V.; Maier, B.; Petry, F.; Piepke, A.; Strecker, H.; Voellinger, M.; Zuber, K.; Balysh, A.; Belyaev, S.T.; Demehin, A.; Gurov, A.; Kondratenko, I.; Lebedev, V.I.; Mueller, A. (Max-Planck-Institut fuer Kernphysik, P.O. Box 103980, 6900 Heidelberg (Germany) Kurchatov Institute, Moscow (Russian Federation) LNGS, Istituto Nazionale di Fisica Nucleare, Gran Sasso, Assergi (Italy))

    1993-05-10

    We have examined the double-beta decay mode accompanied by Majoron emission. After 223 days of measurement corresponding to about 615 kg d or 19.3 mol yr of exposure we find a lower half-life limit for this decay channel of [ital T][sub 1/2][sup 0[nu][chi

  16. Signal and background studies for the search of neutrinoless double beta decay in GERDA

    The GERDA experiment searches for the neutrinoless double beta decay in Ge-76, by operating bare HPGe detectors in ultra-pure liquid Ar. This dissertation presents a first decomposition of the background measured in the current data-taking phase. The background at the energy of interest was found to be dominated by 214Bi, 208Tl and 42K gamma-rays, with secondary contributions from 42K and 214Bi beta-rays, and 210Po alpha-rays. For the forthcoming upgrade of the apparatus, a new HPGe detector design (BEGe) has been studied, with focus on its capability of suppressing the identified backgrounds through pulse shape analysis. This included the development of a comprehensive modeling of the detectors and the experimental characterization of their response to surface interactions. The achieved results show that GERDA can improve the present limit on the neutrinoless double beta decay half-life by an order of magnitude.

  17. Neutrino propagation in nuclear medium and neutrinoless double-beta decay

    Kovalenko, S; Simkovic, F

    2013-01-01

    We discuss a novel effect in neutrinoless double beta decay related with the fact that its underlying mechanisms take place in the nuclear matter environment. We study a particular case of neutrino exchange mechanism and demonstrate possible impact of nuclear medium via Lepton Number Violating (LNV) 4-fermion neutral current interactions of neutrino with quarks from decaying nucleus. The net effect of these interactions is generation of an effective in-medium Majorana neutrino mass matrix. We calculate the corresponding effective masses and construct the neutrino mixing matrix in nuclear medium for the complete set of the relevant 4-fermion neutrino-quark operators. Using the experimental data on neutrinoless double beta decay in combination with the cosmological and tritium beta decay data we evaluate lower limits on the characteristic scales of the studied 4-fermion operators. For the LNV scale we have > 2.4 TeV.

  18. Double beta processes in 96Ru and 104Ru

    An experiment to search for double βdecay processes in 96Ru and 104Ru has been realized in the underground (3600 m w.e.) Gran Sasso National Laboratories (LNGS) of the INFN (Italy). The ruthenium samples with masses of (0.5 - 0.7) kg were measured with the help of ultra-low background HPGe ray spectrometry. After 2162 h of data taking the samples were deeply purified to reduce the 40K internal contamination and further measured during 5479 h. The new improved half life limits on the 2β+/εβ+/2ε processes in 96Ru have been established at level of 1020 yr. The resonant neutrinoless double electron captures to the 2700 and 2713 keV excited states of 96Mo are restricted at 90 % C.L. as T1/2(KL0 ν) >- 2.0·1020 yr and T1/2(2L0ν)>- 3.6·1020 yr, respectively. In addition, the limit on the 2β-decay of 104Ru to the first excited state of 104Pd has been obtained as T1/2>-6.5·1020 yr

  19. Preliminary study of feasibility of an experiment looking for excited state double beta transitions in Tin

    Das, Soumik; Raina, P K; Singh, A K; Rath, P K; Cappella, F; Cerulli, R; Laubenstein, M; Belli, P; Bernabei, R

    2015-01-01

    A first attempt to study the feasibility of an experiment to search for double beta decay in $^{124}$Sn and $^{112}$Sn was carried out by using ultra-low background HPGe detector (244 cm$^{3}$) inside the Gran Sasso National Laboratory (LNGS) of the INFN (Italy). A small sample of natural Sn was examined for 2367.5 h. The radioactive contamination of the sample has been estimated. The data has also been considered to calculate the present sensitivity for the proposed search; half-life limits $\\sim$ $10^{17} - 10^{18}$ years for $\\beta^{+}$EC and EC-EC processes in $^{112}$Sn and $\\sim$ $10^{18}$ years for $\\beta^{-}\\beta^{-}$ transition in $^{124}$Sn were measured. In the last section of the paper the enhancement of the sensitivity for a proposed experiment with larger mass to reach theoretically estimated values of half-lives is discussed.

  20. New Technique for Barium Daughter Ion Identification in a Liquid Xe-136 Double Beta Decay Experiment

    Fairbank, William [Colorado State Univ., Fort Collins, CO (United States)

    2016-06-08

    This work addresses long-standing issues of fundamental interest in elementary particle physics. The most important outcome of this work is a new limit on neutrinoless double beta decay. This is an extremely rare and long sought after type of radioactive decay. If discovered, it would require changes in the standard model of the elementary constituents of matter, and would prove that neutrinos and antineutrinos are the same, a revolutionary concept in particle physics. Neutrinos are major components of the matter in the universe that are so small and so weakly interacting with other matter that their masses have not yet been discovered. A discovery of neutrinoless double beta decay could help determine the neutrino masses. An important outcome of the work on this project was the Colorado State University role in operating the EXO-200 neutrinoless double beta decay experiment and in analysis of the data from this experiment. One type of double beta decay of the isotope 136Xe, the two-neutrino variety, was discovered in this work. Although the other type of double beta decay, the neutrinoless variety, was not yet discovered in this work, a world’s best sensitivity of 1.9x1025 year half-life was obtained. This result rules out a previous claim of a positive result in a different isotope. This work also establishes that the masses of the neutrinos, are less than one millionth of that of electrons. A unique EXO-200 analysis, in which the CSU group had a leading role, has established for the first time ever in a liquid noble gas the fraction of daughter atoms from alpha and beta decay that are ionized. This result has important impact on other pending studies, including nucleon decay and barium tagging. Novel additional discoveries include multiphoton ionization of liquid xenon with UV pulsed lasers, which may find application in calibration of future noble liquid detectors, and studies of association and dissociation reactions of Ba+ ions in gaseous xenon. Through

  1. New limits on double beta decay of 106Cd

    Rukhadze, N. I.; Bakalyarov, A. M.; Briançon, Ch.; Brudanin, V. B.; Čermák, P.; Egorov, V. G.; Klimenko, A. A.; Kovalík, A.; Lebedev, V. I.; Mamedov, F.; Shitov, Yu. A.; Šimkovic, F.; Štekl, I.; Timkin, V. V.; Zhukov, S. V.

    2011-02-01

    Investigation of double electron capture in 106Cd was performed at the Modane underground laboratory (4800 m.w.e.) using the multi-detector spectrometer TGV-2. In Phase I of the experiment, ˜10 g of 106Cd with an enrichment of 75% was measured during 8687 hours. In Phase II, the TGV-2 background was significantly suppressed in comparison with Phase I and the 106Cd mass was increased to ˜13.6 g. New half-life limits (at 90% CL) were obtained for 2νEC/EC decay of 106Cd to the ground state of Pd106 - T1/2>3.0×10 y (Phase I) and T1/2>3.6×10 y (Phase II, 9000 hours), and for 0νEC/EC decay of 106Cd to the 2741 keV excited state of Pd106 - T1/2>1.1×10 y (Phase II).

  2. Design of a self-triggered liquid xenon drift chamber for double-beta decay experiments

    Nuclear double-beta decay is one of the rarest processes in nature with the half life of 1019 - 1024 years. Such process takes place only when a nucleus cannot undergo ordinary beta decay due to energy conservation, or the very strong suppression of energetically allowed transition exists. This process proceeds through the channels of standard second order weak decay (two neutrinos double-beta decay) and lepton number nonconserving, neutrinoless double-beta decay. An isotope of 136Xe possesses attractive properties for the studies on the nuclei subjected to nutrinoless mode. Gaseous or liquid xenon is an excellent working medium for drift chambers, and it can act as both source and detector providing so called active source technique of experiment. In order to search for the neutrinoless mode of 136Xe, the liquid xenon drift chamber was designed, which is composed of three electrodes and four photomultipliers. This drift chamber is described. Th gas handling and vacuum system consisting of a xenon gas purifier, a high vacuum pumping facility and gas storage reservoirs is explained. Event identification, charge division method, the estimation of signal rate and the present state of this study are reported. (K.I.)

  3. New physics effects on neutrinoless double beta decay from right-handed current

    Ge, Shao-Feng; Lindner, Manfred; Patra, Sudhanwa

    2015-10-01

    We study the impact of new physics contributions to neutrinoless double beta decay arising from right-handed current in comparison with the standard mechanism. If the light neutrinos obtain their masses from Type-II seesaw within left-right symmetric model, where the Type-I contribution is suppressed to negligible extent, the right-handed PMNS matrix is the same as its left-handed counterpart, making it highly predictable and testable at next-generation experiments. It is very attractive, especially with recent cosmological constraint favoring the normal hierarchy under which the neutrinoless double beta decay is too small to be observed unless new physics appears as indicated by the recent diboson excess observed at ATLAS. The relative contributions from left- and right-handed currents can be reconstructed with the ratio between lifetimes of two different isotopes as well as the ratio of nuclear matrix elements. In this way, the theoretical uncertainties in the calculation of nuclear matrix elements can be essentially avoided. We also discuss the interplay of neutrinoless double beta decay measurements with cosmology, beta decay, and neutrino oscillation.

  4. Experiments TGV I (double-beta decay of 48Ca) and TGV II (double-beta decay of 106Cd and 48Ca)

    Present status of experiments TGV I and TGV II is given. The TGV I collaboration has studied the double-beta decay of 48Ca with a low-background and high sensitivity Ge multi-detector spectrometer TGV (Telescope Germanium Vertical). The preliminary results of T1/22νββ = (4.2 (+3.3) (-1.3)) x 1019 years and T1/20νββ > 1.5 x 1021 years (90% CL) for double-beta decay of 48Ca has been found after the processing of experimental data obtained after 8700 hours of measuring time using approximately 1 gram of 48Ca. The aim of the experiment TGV II is the development of the experimental methods, construction of spectrometers and measurement of the ββ decay (β+β+, β+ /EC, EC/EC) of 106Cd particularly the 2νEC/EC mode. The theoretical description and performance of the TGV II spectrometer are also given. (author)

  5. Nemo-3 experiment assets and limitations. Perspective for the double {beta} physics; Experience Nemo 3 avantage et limitations. Prospective pour la physique double {beta}

    Augier, C

    2005-06-15

    After an introduction to this report in Chapter 1, I present a status of our knowledge in neutrino physics in Chapter 2. Then, I detail in Chapter 3 all the choices made for the design and realisation of the NEMO 3 detector for the research of double beta decay process. Performance of the detector is presented, concerning both the capacity of the detector to identify the backgrounds and the ability to study all the {beta}{beta} process. I also explain the methods chosen by the NEMO collaboration to reduce the radon activity inside the detector and to make this background negligible today. This chapter, which is written in English, is the 'Technical report of the NEMO 3 detector' and forms an independent report for the NEMO collaborators. I finish this report in Chapter 4 with a ten years prospect for experimental projects in physics, with both the SuperNEMO project and its experiment program, and also by comparing the most interesting experiments, CUORE and GERDA, showing as an example the effect of nuclear matrix elements on the neutrino effective mass measurement. (author)

  6. Double beta decay of ^{64,70}Zn and ^{180,186}W isotopes

    Poda, D V

    2011-01-01

    The results of the experimental investigations of double beta processes in Zinc and Tungsten isotopes with the help of middle volume (117 g, 168 g and 699 g) low-background ZnWO_4 crystal scintillators are presented. The experiment was carried out in the low-background "DAMA/R&D" set-up at the Gran Sasso National Laboratories of the INFN (Italy) at a depth of \\approx3600 m w.e. The total measurement time exceeds ten thousand hours. New improved half-life limits on double electron capture and electron capture with positron emission in ^{64}Zn have been set: T^{2\

  7. Comparison of various extensions of the QRPA formalism for the double-beta decay

    We have used a self-consistent version of the BCS + RQRPA method for a systematic study of the double-beta decay of medium-heavy nuclei with 70 ≤ A ≤ 100. The results have been compared with the previously used approaches, namely the QRPA and the RQRPA approximations. We have shown that inclusion of the quasiparticle correlations at the BCS level reduces ground state correlations in the particle-particle channel of the proton-neutron interaction, resulting in a systematic reduction of the double-beta-decay matrix elements. We also simplified the RQRPA equations significantly obtaining a low-dimensioned set of linear equations for the quasiparticle densities. (author)

  8. Gerda: A new 76Ge Double Beta Decay Experiment at Gran Sasso

    In the new 76Ge double beta decay experiment Gerda [I. Abt et al., arXiv hep-ex/0404039; Gerda proposal, to be submitted to the Gran Sasso scientific committee] bare diodes of enriched 76Ge will be operated in highly pure liquid nitrogen or argon. The goal is to reduce the background around Qββ=2039 keV below 10-3 counts/(kg-bar keV-bar y). With presently available diodes from the Igex and HdMs experiments the current evidence for neutrinoless double beta decay [H.-V. Klapdor-Kleingrothaus, et al., Mod. Phys. Lett. A16 (2001) 2409ff] can unambigously be checked within one year of measurement

  9. SNO+ status and plans for double beta decay search and other neutrino studies

    Andringa, S.; SNO+ Collaboration

    2016-01-01

    SNO+ is a multi-purpose Neutrino Physics experiment, succeeding to the Sudbury Neutrino Observatory by replacing heavy water with liquid scintillator, which can also be loaded with large quantities of double-beta decaying isotope. The scientific goals of SNO+ are the search for neutrinoless double-beta decay, the study of solar neutrinos and of anti-neutrinos from nuclear reactors and the Earth's natural radioactivity, as well as supernovae neutrinos. The installation of the detector at SNOLAB is being completed and commissioning has already started with a dry run. The detector will soon be filled with water and, later, with scintillator. Here we highlight the main detector developments and address the several Physics analysis being prepared for the several planned SNO+ runs.

  10. First Search for Lorentz and CPT Violation in Double Beta Decay with EXO-200

    :,; Barbeau, P S; Beck, D; Belov, V; Breidenbach, M; Brunner, T; Burenkov, A; Cao, G F; Chambers, C; Cleveland, B; Coon, M; Craycraft, A; Daniels, T; Danilov, M; Daugherty, S J; Davis, C G; Davis, J; Delaquis, S; Der Mesrobian-Kabakian, A; DeVoe, R; Díaz, J S; Didberidze, T; Dilling, J; Dolgolenko, A; Dolinski, M J; Dunford, M; Fairbank, W; Farine, J; Feyzbkhsh, S; Feldmeier, W; Fierlinger, P; Fudenberg, D; Gornea, R; Graham, K; Gratta, G; Hall, C; Homiller, S; Hughes, M; Jewell, M J; Jiang, X S; Johnson, A; Johnson, T N; Johnston, S; Karelin, A; Kaufman, L J; Killick, R; Koffas, T; Kravitz, S; Krücken, R; Kuchenkov, A; Kumar, K S; Leonard, D S; Lin, Y H; Ling, J; MacLellan, R; Marino, M G; Mong, B; Moore, D; Nelson, R; Njoya, O; Odian, A; Ostrovskiy, I; Piepke, A; Pocar, A; Prescott, C Y; Retiére, F; Rowson, P C; Russell, J J; Schubert, A; Sinclair, D; Smith, E; Stekhanov, V; Tarka, M; Tolba, T; Tsang, R; Twelker, K; Vuilleumier, J -L; Vogel, P; Waite, A; Walton, J; Walton, T; Weber, M; Wen, L J; Wichoski, U; Wood, J; Yang, L; Yen, Y -R; Zeldovich, O Ya

    2016-01-01

    A search for Lorentz- and CPT-violating signals in the double beta decay spectrum of $^{136}$Xe has been performed using an exposure of 100 kg$\\cdot$yr with the EXO-200 detector. No significant evidence of the spectral modification due to isotropic Lorentz-violation was found, and a two-sided limit of $-2.65 \\times 10^{-5 } \\; \\textrm{GeV} < \\mathring{a}^{(3)}_{\\text{of}} < 7.60 \\times 10^{-6} \\; \\textrm{GeV}$ is placed on the relevant coefficient within the Standard-Model Extension (SME). This is the first experimental study of the effect of the SME-defined oscillation-free and momentum-independent neutrino coupling operator on the double beta decay process.

  11. Constraining New Physics with a Positive or Negative Signal of Neutrino-less Double Beta Decay

    Bergstrom, Johannes; Ohlsson, Tommy

    2011-01-01

    We investigate numerically how accurately one could constrain the strengths of different short-range contributions to neutrino-less double beta decay in effective field theory. Depending on the outcome of near-future experiments yielding information on the neutrino masses, the corresponding bounds or estimates can be stronger or weaker. A particularly interesting case, resulting in strong bounds, would be a positive signal of neutrino-less double beta decay that is consistent with complementary information from neutrino oscillation experiments, kinematical determinations of the neutrino mass, and measurements of the sum of light neutrino masses from cosmological observations. The keys to more robust bounds are improvements of the knowledge of the nuclear physics involved and a better experimental accuracy.

  12. Double beta decay physics beyond the standard model now and in future (Genius)

    Nuclear double beta decay provides an extraordinarily broad potential to search for beyond standard model physics, probing already now the TeV scale, on which new physics should manifest itself. These possibilities are reviewed here. First, the results of present generation experiments are presented. The most sensitive one of them - the Heidelberg-Moscow experiment in the Gran Sasso - probes the electron mass now in the sub-eV region and will reach a limit of ∼ 0.1 eV in a few years. Basing to a large extent on the theoretical work of the Heidelberg Double Beta Group in the last two years, results are obtained also for SUSY models (R-parity breaking, sneutrino mass), leptoquarks (leptoquark-Higgs coupling), compositeness, right-handed W-boson mass and others

  13. Electron capture decay of {sup 116}In and nuclear structure of double {beta} decays

    Bhattacharya, M.; Garcia, A.; Ortiz, C.E.; Kaloskamis, N.I. [University of Notre Dame, Notre Dame, Indiana 46556 (United States); Hindi, M.M. [Physics Department, Tennessee Technological University, Cookeville, Tennessee 38505 (United States); Norman, E.B. [Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Davids, C.N. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Civitarese, O. [Department of Physics, University of La Plata, C. C. 67, 1900-La Plata (Argentina); Suhonen, J. [Department of Physics, University of Jyvaeskylae, P.O. Box 35, SF-40351, Jyvaeskylae (Finland)

    1998-08-01

    Quasiparticle-random-phase-approximation (QRPA) calculations of double {beta} decays have not been able to reproduce data in the A=100 system. We propose the A=116 system{emdash}because of its smaller deformation{emdash}as a simpler system to test QRPA calculations. We present results of two experiments we performed, which determine the electron-capture-decay branch of {sup 116}In to be (2.27{plus_minus}0.63){times}10{sup {minus}2}{percent}, from which we deduce logft=4.39{sub {minus}0.15}{sup +0.10}. We present QRPA calculations and compare their predictions to experimental data. Finally we use these calculations to predict the 2{nu} double-{beta}-decay rate of {sup 116}Cd to the ground and excited states of {sup 116}Sn. {copyright} {ital 1998} {ital The American Physical Society}

  14. Analysis of the intermediate-state contributions to neutrinoless double beta-minus decays

    Hyvärinen, Juhani

    2016-01-01

    A comprehensive analysis of the structure of the nuclear matrix elements (NMEs) of neutrinoless double beta-minus decays to the 0^+ ground and first excited states is performed in terms of the contributing multipole states in the intermediate nuclei of neutrinoless double beta-minus transitions. We concentrate on the transitions mediated by the light (l-NMEs) Majorana neutrinos. As nuclear model we use the proton-neutron quasiparticle random-phase approximation (pnQRPA) with a realistic two-nucleon interaction based on the Bonn one-boson-exchange G matrix. In the computations we include the appropriate short-range correlations, nucleon form factors, higher-order nucleonic weak currents and restore the isospin symmetry by the isoscalar-isovector decomposition of the particle-particle proton-neutron interaction parameter g_{pp}.

  15. Systematics of neutrinoless double beta decay matrix elements in a major shell

    We analyze nuclear matrix elements (NME) of neutrinoless double beta decay calculated for the Cadmium isotopes. Energy density functional methods including beyond mean field effects such as symmetry restoration and shape mixing are used. Strong shell effects are found associated to the underlying nuclear structure of the initial and final nuclei. Furthermore, we show that NME for two-neutrino double beta decay evaluated in the closure approximation, M2νcl, display a constant proportionality with respect to the Gamow-Teller part of the neutrinoless NME, M0νGT. This opens the possibility of determining the M0νGT matrix elements from β-+ Gamow-Teller strength functions. Finally, the interconnected role of deformation, pairing, configuration mixing and shell effects in the NMEs is discussed.

  16. The influence of pairing on the nuclear matrix elements of the neutrinoless double beta decays

    Caurier, E; Nowacki, F; Poves, A

    2007-01-01

    We study in this letter the behavior of the neutrinoless double beta decay nuclear matrix elements (NME's) in the framework of the Interacting Shell Model. We analize them in terms of the total angular momentum of the decaying neutron pair and as a function of the seniority truncations in the nuclear wave functions. This point of view turns out to be very adequate to gauge the accuracy of the NME's predicted by different nuclear structure models. In addition, it gives back the due protagonism in this process to the pairing interaction, the interaction which is responsible for the very existence of double beta decay emitters. We show that low seniority approximations, such as the quasiparticle RPA in an spherical basis, tend to overestimate the values of the NME's.

  17. Latest results of NEXT-DEMO, the prototype of the NEXT 100 double beta decay experiment

    Serra, L; Martin-Albo, J; Sorel, M; Gomez-Cadenas, J J

    2014-01-01

    NEXT-DEMO is a 1:4.5 scale prototype of the NEXT100 detector, a high-pressure xenon gas TPC that will search for the neutrinoless double beta decay of $^{136}$Xe. X-ray energy depositions produced by the de-excitation of Xenon atoms after the interaction of gamma rays from radioactive sources have been used to characterize the response of the detector obtaining the spatial calibration needed for close-to-optimal energy resolution. Our result, 5.5% FWHM at 30 keV, extrapolates to 0.6% FWHM at the Q value of $^{136}$Xe. Additionally, alpha decays from radon have been used to measure several detection properties and parameters of xenon gas such as electron-ion recombination, electron drift velocity, diffusion and primary scintillation light yield. Alpha spectroscopy is also used to quantify the activity of radon inside the detector, a potential source of background for most double beta decay experiments.

  18. Status of the GERDA experiment aimed to search for neutrinoless double beta decay of 76Ge

    Smolnikov, Anatoly A.; Collaboration, for the GERDA

    2008-01-01

    The progress in the development of the new international Gerda (GErmanium Detector Array) experiment is presented. Main purpose of the experiment is to search for the neutrinoless double beta decay of 76Ge. The experimental set up is under construction in the underground laboratory of LNGS. Gerda will operate with bare germanium semiconductor detectors (enriched in 76Ge) situated in liquid argon. In the Phase I the existing enriched detectors from the previous Heidelberg-Moscow and IGEX exper...

  19. Status and perspective of the GERDA neutrinoless double beta decay experiment

    Knöpfle, K. T.; Gerda Collaboration

    2012-09-01

    Gerda, the GERManium Detector Array [1], is a new double beta decay experiment which is currently under commissioning in the Infn National Gran Sasso Laboratory (Lngs), Italy. It is implementing a new shielding concept by operating bare Ge diodes - enriched in 76Ge - in high purity liquid argon supplemented by a water shield. The paper presents the status of the experiment, results from the commissioning, and a summary of planned future activities.

  20. The 76Ge Double-Beta Decay Experiment GERDA at LNGS

    In the second generation 76Ge double-beta decay experiment GERDA bare detectors made out of enriched 76Ge will be operated in an cryogenic fluid shield. The goal of the approved GERDA project is to reduce the background around Q = 2039 keV below 10-3 counts/(kg keVy) and reach a sensitivity for neutrinoless ββ decay of T1/2 > 2 x 1026 years after an exposure of 100 kg years. (author)

  1. Sensitivity of experiment on double beta decay of 150Nd search

    The possibility of using big area scintillation plates on the basis of polystyrene for creation of the detector of neutrinoless 150Nd double beta decay with sensitivity to half-life period of 1025 years is investigated. The estimations of necessary isotope mass depending on the energy resolution are demonstrated. It is shown that the given sensitivity can be realized by means of such a detector at an isotope mass about 85 kg

  2. Left-Right Symmetry: From the LHC to Neutrinoless Double Beta Decay

    The Large Hadron Collider has the potential to probe the scale of left-right symmetry restoration and the associated lepton number violation. Moreover, it offers the hope of measuring the right-handed leptonic mixing matrix. We show how this, together with constraints from lepton flavor violating processes, can be used to make predictions for neutrinoless double beta decay. We illustrate this connection in the case of the type-II seesaw.

  3. The low background spectrometer TGV II for double beta decay measurements

    Beneš, P.; Čermák, P.; Gusev, K. N.; Klimenko, A. A.; Kovalenko, V. E.; Kovalík, A.; Rukhadze, N. I.; Salamatin, A. V.; Šimkovic, F.; Štekl, I.; Timkin, V. V.; Vylov, Ts.

    2006-12-01

    The low-background multi-HPGe spectrometer TGV II installed in the Modane Underground Laboratory (France) is described in detail and the results of the background measurements are reported. The spectrometer is focused on the double beta decay measurements with two isotopes— 106Cd ( 2νEC/EC mode) and 48Ca ( ββ mode). A basic summary of the physics of ββ decay (especially EC/EC mode) is also given.

  4. The low background spectrometer TGV II for double beta decay measurements

    The low-background multi-HPGe spectrometer TGVII installed in the Modane Underground Laboratory (France) is described in detail and the results of the background measurements are reported. The spectrometer is focused on the double beta decay measurements with two isotopes-106Cd (2νEC/EC mode) and 48Ca (ββ mode). A basic summary of the physics of ββ decay (especially EC/EC mode) is also given

  5. Uncertainties in nuclear matrix elements for neutrinoless double-beta decay

    I briefly review calculations of the matrix elements governing neutrinoless double-beta decay, focusing on attempts to assign uncertainties. At present, systematic error dominates statistical error and assigning uncertainty is difficult. For some purposes, however, statistical assessment of uncertainty is profitable and, after describing the nuclear models in which matrix elements are commonly calculated, I highlight some statistical uncertainty analysis within the quasiparticle random-phase approximation. I also propose, in broad terms, strategies for reducing both systematic and statistical error. (paper)

  6. Simulation of double beta decay in the ''SeXe'' TPC

    Mauger, F.

    2007-04-01

    In 2004, the NEMO collaboration has started some preliminary studies for a next-generation double beta decay experiment: SuperNEMO. The possibility to use a large gaseous TPC has been investigated using simulation and extrapolation of former experiments. In this talk, I report on the reasons why such techniques have not been selected in 2004 and led the NEMO collaboration to reuse the techniques implemented within the NEMO3 detector.

  7. Simulation of double beta decay in the 'SeXe' TPC

    Mauger, F [LPC Caen and University of Caen, ENSICAEN, 6 Bd Marechal Juin, 14050 CAEN CEDEX 4 (France)

    2007-04-15

    In 2004, the NEMO collaboration has started some preliminary studies for a next-generation double beta decay experiment: SuperNEMO. The possibility to use a large gaseous TPC has been investigated using simulation and extrapolation of former experiments. In this talk, I report on the reasons why such techniques have not been selected in 2004 and led the NEMO collaboration to reuse the techniques implemented within the NEMO3 detector.

  8. Characterization of a ZnSe scintillating bolometer prototype for neutrinoless double beta decay search

    Tenconi M.; Giuliani A.; Nones C.; Pessina G.; Plantevin O.; Rusconi C.

    2014-01-01

    As proposed in the LUCIFER project, ZnSe crystals are attractive materials to realize scintillating bolometers aiming at the search for neutrinoless double beta decay of the promising isotope 82Se. However, the optimization of the ZnSe-based detectors is rather complex and requires a wide-range investigation of the crystal features: optical properties, crystalline quality, scintillation yields and bolometric behaviour. Samples tested up to now show problems in the reproducibility of crucial a...

  9. Test of special relativity and equivalence principle from neutrinoless double beta decay

    We generalize the formalism for testing Lorentz invariance and the weak equivalence principle in the neutrino sector. While neutrino oscillation bounds constrain the region of large mixing of the the weak and gravitational eigenstates, we obtain new constraints on violations of Lorentz invariance and the equivalence principle from neutrinoless double beta decay. These bounds apply even in the case of no mixing and thus probe a totally unconstrained region in the parameter space. (orig.)

  10. A Segmented, Enriched N-type Germanium Detector for Neutrinoless Double Beta-Decay Experiments

    Leviner, L. E.; Aalseth, C. E.; Ahmed, M. W.; Avignone III, F. T.; Back, H. O.; Barabash, A. S.; Boswell, M.(Los Alamos National Laboratory, Los Alamos, NM 87545, USA); L. De Braeckeleer(Washington U., Seattle); Brudanin, V. B.; Chan, Y-D.; Egorov, V. G.; Elliott, S. R.; Gehman, V. M.; Hossbach, T. W.; Kephart, J. D.

    2013-01-01

    We present data characterizing the performance of the first segmented, N-type Ge detector, isotopically enriched to 85% $^{76}$Ge. This detector, based on the Ortec PT6x2 design and referred to as SEGA (Segmented, Enriched Germanium Assembly), was developed as a possible prototype for neutrinoless double beta-decay measurements by the {\\sc Majorana} collaboration. We present some of the general characteristics (including bias potential, efficiency, leakage current, and integral cross-talk) fo...

  11. Radiopurity assessment of the tracking readout for the NEXT double beta decay experiment

    Cebrián, S.; J. PÉREZ; Bandac, I.; Labarga, L.; V. Álvarez; Barrado, A. I.; Bettini, A.; Borges, F. I. G. M.; Camargo, M.; Cárcel, S; A. Cervera(IFIC); Conde, C. A. N.; Conde, E.; Dafni, T.; Díaz, J.

    2014-01-01

    The Neutrino Experiment with a Xenon Time-Projection Chamber (NEXT) is intended to investigate the neutrinoless double beta decay of 136Xe, which requires a severe suppression of potential backgrounds; therefore, an extensive screening and selection process is underway to control the radiopurity levels of the materials to be used in the experimental set-up of NEXT. The detector design combines the measurement of the topological signature of the event for background discrimination with the ene...

  12. Solar neutrino interactions with liquid scintillators used for double beta decay experiments

    Ejiri, Hiroyasu

    2016-01-01

    Solar neutrinos interact with double beta decay detectors (DBD) and hence will contribute to backgrounds (BG) for DBD experiments. Background contributions due to solar neutrinos are evaluated for their interactions with atomic electrons and nuclei in liquid scintillation detectors used for DBD experiments. They are shown to be serious backgrounds for high sensitivity DBD experiments to search for the Majorana neutrino masses in the inverted and normal hierarchy regions.

  13. Probing the quenching of gA by single and double beta decays

    Ground-state-to-ground-state two-neutrino double beta (2νββ) decays and single beta (EC and β−) decays are studied for the A=100 (100Mo-100Tc-100Ru), A=116 (116Cd-116In-116Sn) and A=128 (128Te-128I-128Xe) nuclear systems by using the proton–neutron quasiparticle random-phase approximation exploiting realistic effective interactions in very large single-particle bases. The aim of this exercise is to see if both the single-beta and double-beta decay observables related to the ground states of the initial, intermediate and final nuclei participant in the decays can be described simultaneously by changing the value of the axial-vector coupling constant gA. In spite of the very different responses to single and 2νββ decays of the considered nuclear systems, the obtained results point consistently to a quenched effective value of gA that is (slightly) different for the single and 2νββ decays

  14. Double-loaded liposomes encapsulating Quercetin and Quercetin beta-cyclodextrin complexes: Preparation, characterization and evaluation

    Jessy Shaji

    2012-01-01

    Full Text Available Beta-cyclodextrin (CD inclusion complexes of Quercetin were formed and characterized by Differential scanning calorimetry (DSC and Fourier transform infra-red spectroscopy (FTIR spectroscopy. Plain Quercetin liposomes using phosphatidylcholine and cholesterol were prepared and optimized. Factors such as ratio of lipids employed, drug:lipid ratio, etc. were fine tuned and optimized to achieve maximum entrapment of the Quercetin into the bilayer. Entrapment was further enhanced by double loading the liposomes. These were prepared by incorporating Quercetin as a plain drug as well as the inclusion complexes within the lipid bilayer and the aqueous compartment, respectively, of the liposomes using the thin film hydration technique. The highest entrapment was achieved with a lipid ratio of 9:1, and the amount of plain drug entering the bilayer was 1/10 th the amount of lipid employed. Double loading increased this value to one part of drug per five parts of lipid when Quercetin-beta-CD (1:1 mol/mol was entrapped. The release of Quercetin from liposomes was highest when the drug was entrapped in the form of a complex with beta cylodextrin. The high entrapment ability of Quercetin in the form of plain drug as well as beta cylodextrin-Quercetin complexes in comparison with plain drug is an indubitable advantage of this approach.

  15. On neutrinoless double beta decay in the minimal left-right symmetric model

    We analyze the general phenomenology of neutrinoless double beta decay in theminimal left-right symmetric model. We study under which conditions a New Physics dominated neutrinoless double beta decay signal can be expected in the future experiments. We show that the correlation among the different contributions to the process, which arises from the neutrino mass generation mechanism, can play a crucial role. We have found that, if no fine tuned cancelation is involved in the light-active neutrino contribution, a New Physics signal can be expected mainly from the WR-WR channel. An interesting exception is the WL-WR channel which can give a dominant contribution to the process if the right-handed neutrino spectrum is hierarchical with M1 2, M3 >or similar GeV. We also discuss if a New Physics signal in neutrinoless double beta decay experiments is compatible with the existence of a successful Dark Matter candidate in the left-right symmetric models. It turns out that, although it is not a generic feature of the theory, it is still possible to accommodate such a signal with a KeV sterile neutrino as dark matter. (orig.)

  16. Results on neutrinoless double beta decay of 76Ge from GERDA Phase I

    Agostini, M; Andreotti, E; Bakalyarov, A M; Balata, M; Barabanov, I; Heider, M Barnabé; Barros, N; Baudis, L; Bauer, C; Becerici-Schmidt, N; Bellotti, E; Belogurov, S; Belyaev, S T; Benato, G; Bettini, A; Bezrukov, L; Bode, T; Brudanin, V; Brugnera, R; Budjáš, D; Caldwell, A; Cattadori, C; Chernogorov, A; Cossavella, F; Demidova, E V; Domula, A; Egorov, V; Falkenstein, R; Ferella, A; Freund, K; Frodyma, N; Gangapshev, A; Garfagnini, A; Gotti, C; Grabmayr, P; Gurentsov, V; Gusev, K; Guthikonda, K K; Hampel, W; Hegai, A; Heisel, M; Hemmer, S; Heusser, G; Hofmann, W; Hult, M; Inzhechik, L V; Ioannucci, L; Csáthy, J Janicskó; Jochum, J; Junker, M; Kihm, T; Kirpichnikov, I V; Kirsch, A; Klimenko, A; Knöpfle, K T; Kochetov, O; Kornoukhov, V N; Kuzminov, V V; Laubenstein, M; Lazzaro, A; Lebedev, V I; Lehnert, B; Liao, H Y; Lindner, M; Lippi, I; Liu, X; Lubashevskiy, A; Lubsandorzhiev, B; Lutter, G; Macolino, C; Machado, A A; Majorovits, B; Maneschg, W; Misiaszek, M; Nemchenok, I; Nisi, S; O'Shaughnessy, C; Pandola, L; Pelczar, K; Pessina, G; Potenza, %F; Pullia, A; Riboldi, S; Rumyantseva, N; Sada, C; Salathe, M; Schmitt, C; Schreiner, J; Schulz, O; Schwingenheuer, B; Schönert, S; Shevchik, E; Shirchenko, M; Simgen, H; Smolnikov, A; Stanco, L; Strecker, H; Tarka, M; Ur, C A; Vasenko, A A; Volynets, O; von Sturm, K; Wagner, V; Walter, M; Wegmann, A; Wester, T; Wojcik, M; Yanovich, E; Zavarise, P; Zhitnikov, I; Zhukov, S V; Zinatulina, D; Zuber, K; Zuzel, G

    2013-01-01

    Neutrinoless double beta decay is a process that violates lepton number conservation. It is predicted to occur in extensions of the Standard Model of particle physics. This Letter reports the results from Phase I of the GERmanium Detector Array (GERDA) experiment at the Gran Sasso Laboratory (Italy) searching for neutrinoless double beta decay of the isotope 76Ge. Data considered in the present analysis have been collected between November 2011 and May 2013 with a total exposure of 21.6 kgyr. A blind analysis is performed. The background index is about 1.10^{-2} cts/(keV kg yr) after pulse shape discrimination. No signal is observed and a lower limit is derived for the half-life of neutrinoless double beta decay of 76Ge, T_1/2 > 2.1 10^{25} yr (90% C.L.). The combination with the results from the previous experiments with 76Ge yields T_1/2 > 3.0 10^{25} yr (90% C.L.).

  17. Double-beta decay investigation with highly pure enriched {sup 82}Se for the LUCIFER experiment

    Beeman, J.W. [Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Bellini, F.; Casali, N.; Ferroni, F.; Piperno, G. [Sapienza Universita di Roma, Dipartimento di Fisica, Rome (Italy); INFN, Sezione di Roma, Rome (Italy); Benetti, P. [Universita di Pavia, Dipartimento di Chimica, Pavia (Italy); INFN, Sezione di Pavia, Pavia (Italy); Cardani, L. [Sapienza Universita di Roma, Dipartimento di Fisica, Rome (Italy); Princeton University, Physics Department, Princeton, NJ (United States); Chiesa, D.; Clemenza, M.; Gironi, L.; Maino, M. [Universita di Milano-Bicocca, Dipartimento di Fisica, Milan (Italy); INFN, Sezione di Milano Bicocca, Milan (Italy); Dafinei, I.; Orio, F.; Tomei, C.; Vignati, M. [INFN, Sezione di Roma, Rome (Italy); Di Domizio, S. [INFN, Sezione di Genova, Genoa (Italy); Universita di Genova, Dipartimento di Fisica, Genoa (Italy); Giuliani, A. [Centre de Spectrometrie de Masse, Orsay (France); Gotti, C.; Pessina, G.; Previtali, E.; Rusconi, C. [INFN, Sezione di Milano Bicocca, Milan (Italy); Laubenstein, M.; Nisi, S.; Pattavina, L.; Pirro, S.; Schaeffner, K. [INFN, Laboratori Nazionali del Gran Sasso, Assergi (L' Aquila) (Italy); Nagorny, S.; Pagnanini, L. [Gran Sasso Science Institute, L' Aquila (Italy); Nones, C. [SPP Centre de Saclay, CEA, Irfu, Gif-sur-Yvette (France)

    2015-12-15

    The LUCIFER project aims at deploying the first array of enriched scintillating bolometers for the investigation of neutrinoless double-beta decay of {sup 82}Se. The matrix which embeds the source is an array of ZnSe crystals, where enriched {sup 82}Se is used as decay isotope. The radiopurity of the initial components employed for manufacturing crystals, that can be operated as bolometers, is crucial for achieving a null background level in the region of interest for double-beta decay investigations. In this work, we evaluated the radioactive content in 2.5 kg of 96.3 % enriched {sup 82}Se metal, measured with a high-purity germanium detector at the Gran Sasso deep underground laboratory. The limits on internal contaminations of primordial decay chain elements of {sup 232}Th, {sup 238}U and {sup 235}U are respectively: <61, <110 and <74 μBq/kg at 90 % C.L. The extremely low-background conditions in which the measurement was carried out and the high radiopurity of the {sup 82}Se allowed us to establish the most stringent lower limits on the half-lives of the double-beta decay of {sup 82}Se to 0{sub 1}{sup +}, 2{sub 2}{sup +} and 2{sub 1}{sup +} excited states of {sup 82}Kr of 3.4.10{sup 22}, 1.3.10{sup 22} and 1.0.10{sup 22} y, respectively, with a 90 % C.L. (orig.)

  18. Double-beta decay investigation with highly pure enriched ^{82}Se for the LUCIFER experiment

    Beeman, J. W.; Bellini, F.; Benetti, P.; Cardani, L.; Casali, N.; Chiesa, D.; Clemenza, M.; Dafinei, I.; Domizio, S. Di; Ferroni, F.; Gironi, L.; Giuliani, A.; Gotti, C.; Laubenstein, M.; Maino, M.; Nagorny, S.; Nisi, S.; Nones, C.; Orio, F.; Pagnanini, L.; Pattavina, L.; Pessina, G.; Piperno, G.; Pirro, S.; Previtali, E.; Rusconi, C.; Schäffner, K.; Tomei, C.; Vignati, M.

    2015-12-01

    The LUCIFER project aims at deploying the first array of enriched scintillating bolometers for the investigation of neutrinoless double-beta decay of ^{82}Se. The matrix which embeds the source is an array of ZnSe crystals, where enriched ^{82}Se is used as decay isotope. The radiopurity of the initial components employed for manufacturing crystals, that can be operated as bolometers, is crucial for achieving a null background level in the region of interest for double-beta decay investigations. In this work, we evaluated the radioactive content in 2.5 kg of 96.3 % enriched ^{82}Se metal, measured with a high-purity germanium detector at the Gran Sasso deep underground laboratory. The limits on internal contaminations of primordial decay chain elements of ^{232}Th, ^{238}U and ^{235}U are respectively: <61, <110 and <74 μ Bq/kg at 90 % C.L. The extremely low-background conditions in which the measurement was carried out and the high radiopurity of the ^{82}Se allowed us to establish the most stringent lower limits on the half-lives of the double-beta decay of ^{82}Se to 0^+_1, 2^+_2 and 2^+_1 excited states of ^{82}Kr of 3.4\\cdot 10^{22}, 1.3\\cdot 10^{22} and 1.0\\cdot 10^{22} y, respectively, with a 90 % C.L.

  19. Double-beta decay investigation with highly pure enriched 82Se for the LUCIFER experiment

    The LUCIFER project aims at deploying the first array of enriched scintillating bolometers for the investigation of neutrinoless double-beta decay of 82Se. The matrix which embeds the source is an array of ZnSe crystals, where enriched 82Se is used as decay isotope. The radiopurity of the initial components employed for manufacturing crystals, that can be operated as bolometers, is crucial for achieving a null background level in the region of interest for double-beta decay investigations. In this work, we evaluated the radioactive content in 2.5 kg of 96.3 % enriched 82Se metal, measured with a high-purity germanium detector at the Gran Sasso deep underground laboratory. The limits on internal contaminations of primordial decay chain elements of 232Th, 238U and 235U are respectively: <61, <110 and <74 μBq/kg at 90 % C.L. The extremely low-background conditions in which the measurement was carried out and the high radiopurity of the 82Se allowed us to establish the most stringent lower limits on the half-lives of the double-beta decay of 82Se to 01+, 22+ and 21+ excited states of 82Kr of 3.4.1022, 1.3.1022 and 1.0.1022 y, respectively, with a 90 % C.L. (orig.)

  20. Double-beta decay investigation with highly pure enriched {sup 82}Se for the LUCIFER experiment

    Beeman, J. W. [Lawrence Berkeley National Laboratory, 94720, Berkeley, CA (United States); Bellini, F. [Dipartimento di Fisica, Sapienza Università di Roma, 00185, Rome (Italy); INFN, Sezione di Roma, 00185, Rome (Italy); Benetti, P. [Dipartimento di Chimica, Università di Pavia, 27100, Pavia (Italy); INFN, Sezione di Pavia, 27100, Pavia (Italy); Cardani, L. [Dipartimento di Fisica, Sapienza Università di Roma, 00185, Rome (Italy); Physics Department, Princeton University, 08544, Princeton, NJ (United States); Casali, N. [Dipartimento di Fisica, Sapienza Università di Roma, 00185, Rome (Italy); INFN, Sezione di Roma, 00185, Rome (Italy)

    2015-12-13

    The LUCIFER project aims at deploying the first array of enriched scintillating bolometers for the investigation of neutrinoless double-beta decay of {sup 82}Se. The matrix which embeds the source is an array of ZnSe crystals, where enriched {sup 82}Se is used as decay isotope. The radiopurity of the initial components employed for manufacturing crystals, that can be operated as bolometers, is crucial for achieving a null background level in the region of interest for double-beta decay investigations. In this work, we evaluated the radioactive content in 2.5 kg of 96.3 % enriched {sup 82}Se metal, measured with a high-purity germanium detector at the Gran Sasso deep underground laboratory. The limits on internal contaminations of primordial decay chain elements of {sup 232}Th, {sup 238}U and {sup 235}U are respectively: <61, <110 and <74 μBq/kg at 90 % C.L. The extremely low-background conditions in which the measurement was carried out and the high radiopurity of the {sup 82}Se allowed us to establish the most stringent lower limits on the half-lives of the double-beta decay of {sup 82}Se to 0{sub 1}{sup +}, 2{sub 2}{sup +} and 2{sub 1}{sup +} excited states of {sup 82}Kr of 3.4·10{sup 22}, 1.3·10{sup 22} and 1.0·10{sup 22} y, respectively, with a 90 % C.L.

  1. A search for various double beta decay modes of Cd, Te, and Zn isotopes

    Various double beta decay modes of Cd, Zn, and Te isotopes are explored with the help of CdTe and CdZnTe semiconductor detectors. The data set is splitted in an energy range below 1 MeV having a statistics of 134.5 g d and one above 1 MeV resulting in 532 g d. No signals were observed in all channels under investigation. New improved limits for the neutrinoless double beta decay of 70Zn of T1/2>1.3x1016 yrs (90% CL), the longest standing limit of all double beta isotopes, and 0νβ+EC of 120Te of T1/2>2.2x1016 yrs (90% CL) are given. For the first time a limit on the half-life of the 2νECEC of 120Te of T1/2>9.4x1015 yrs (90% CL) is obtained. In addition, limits on 2νECEC for ground state transitions of 106Cd, 108Cd, and 64Zn are improved. The obtained results even under rough background conditions show the reliability of CdTe semiconductor detectors for rare nuclear decay searches

  2. Double-beta decay investigation with highly pure enriched 82Se for the LUCIFER experiment

    The LUCIFER project aims at deploying the first array of enriched scintillating bolometers for the investigation of neutrinoless double-beta decay of 82Se. The matrix which embeds the source is an array of ZnSe crystals, where enriched 82Se is used as decay isotope. The radiopurity of the initial components employed for manufacturing crystals, that can be operated as bolometers, is crucial for achieving a null background level in the region of interest for double-beta decay investigations. In this work, we evaluated the radioactive content in 2.5 kg of 96.3 % enriched 82Se metal, measured with a high-purity germanium detector at the Gran Sasso deep underground laboratory. The limits on internal contaminations of primordial decay chain elements of 232Th, 238U and 235U are respectively: <61, <110 and <74 μBq/kg at 90 % C.L. The extremely low-background conditions in which the measurement was carried out and the high radiopurity of the 82Se allowed us to establish the most stringent lower limits on the half-lives of the double-beta decay of 82Se to 01+, 22+ and 21+ excited states of 82Kr of 3.4·1022, 1.3·1022 and 1.0·1022 y, respectively, with a 90 % C.L

  3. Exploring the Neutrinoless Double Beta Decay in the Inverted Neutrino Hierarchy with Bolometric Detectors

    Artusa, D. R.; Azzolini, O.; Balata, M.; Banks, T. I.; Bari, G.; Beeman, J.; Bellini, F.; Bersani, A.; Biassoni, M.; Brofferio, C.; Bucci, C.; Cai, X. Z.; Camacho, A.; Canonica, L.; Cao, X. G.; Capelli, S.; Carbone, L.; Cardani, L.; Carrettoni, M.; Casali, N.; Chiesa, D.; Chott, N.; Clemenza, M.; Cosmelli, C.; Cremonesi, O.; Creswick, R. J.; Dafinei, I.; Dally, A.; Datskov, V.; Biasi, A. De; Deninno, M. M.; Domizio, S. Di; Vacri, M. L. di; Ejzak, L.; Fang, D. Q.; Farach, H. A.; Faverzani, M.; Fernandes, G.; Ferri, E.; Ferroni, F.; Fiorini, E.; Franceschi, M. A.; Freedman, S. J.; Fujikawa, B. K.; Giachero, A.; Gironi, L.; Giuliani, A.; Goett, J.; Gorla, P.; Gotti, C.; Gutierrez, T. D.; Haller, E. E.; Han, K.; Heeger, K. M.; Hennings-Yeomans, R.; Huang, H. Z.; Kadel, R.; Kazkaz, K.; Keppel, G.; Kolomensky, Yu. G.; Li, Y. L.; Ligi, C.; Liu, X.; Ma, Y. G.; Maiano, C.; Maino, M.; Martinez, M.; Maruyama, R. H.; Mei, Y.; Moggi, N.; Morganti, S.; Napolitano, T.; Nisi, S.; Norman, E. B.; Nucciotti, A.; O' Donnell, T.; Orio, F.; Orlandi, D.; Ouellet, J. L.; Pallavicini, M.; Palmieri, V.; Pattavina, L.; Pavan, M.; Pedretti, M.; Pessina, G.; Pettinacci, V.; Piperno, G.; Pira, C.; Pirro, S.; Previtali, E.; Rampazzo, V.; Rosenfeld, C.; Rusconi, C.; Sala, E.; Sangiorgio, S.; Scielzo, N. D.; Sisti, M.; Smith, A. R.; Taffarello, L.; Tenconi, M.; Terranova, F.; Tian, W. D.; Tomei, C.; Trentalange, S.; Ventura, G.; Vignati, M.; Wang, B. S.; Wang, H. W.; Wielgus, L.; Wilson, J.; Winslow, L. A.; Wise, T.; Woodcraft, A.; Zanotti, L.; Zarra, C.; Zhu, B. X.

    2014-10-15

    Neutrinoless double beta decay (0nubb) is one of the most sensitive probes for physics beyond the Standard Model, providing unique information on the nature of neutrinos. In this paper we review the status and outlook for bolometric 0{nu}{beta}{beta} decay searches. We summarize recent advances in background suppression demonstrated using bolometers with simultaneous readout of heat and light signals. We simulate several configurations of a future CUORE-like bolometer array which would utilize these improvements and present the sensitivity reach of a hypothetical next-generation bolometric 0{nu}{beta}{beta} experiment. We demonstrate that a bolometric experiment with the isotope mass of about 1 ton is capable of reaching the sensitivity to the effective Majorana neutrino mass (|m{sub ee}|) of order 10-20 meV, thus completely exploring the so-called inverted neutrino mass hierarchy region. We highlight the main challenges and identify priorities for an R&D program addressing them.

  4. A first search of excited states double beta and double electron capture decays of {sup 110}Pd and {sup 102}Pd

    Lehnert, B., E-mail: Bjoern.Lehnert@mailbox.tu-dresden.de [Inst. fuer Kern- und Teilchenphysik, Technische Universitaet Dresden, 01069 Dresden (Germany); Zuber, K., E-mail: Zuber@physik.tu-dresden.de [Inst. fuer Kern- und Teilchenphysik, Technische Universitaet Dresden, 01069 Dresden (Germany)

    2011-11-03

    A search for double beta decays of the palladium isotopes {sup 110}Pd and {sup 102}Pd into excited states of their daughters was performed and first half-life limits for the 2{nu}{beta}{beta} and 0{nu}{beta}{beta} decays into first excited 0{sup +} and 2{sup +} states of 5.89x10{sup 19} yr and 4.40x10{sup 19} yr (95% CL) for the {sup 110}Pd decay were obtained. The half-life limits for the corresponding double electron capture transition of {sup 102}Pd are 7.64x10{sup 18} yr and 2.68x10{sup 18} yr (95% CL) respectively. These are the first measurements for {sup 102}Pd.

  5. Search for double beta decay processes in 106Cd with the help of 106CdWO4 crystal scintillator

    Belli, P; Boiko, R S; Brudanin, V B; Cappella, F; Caracciolo, V; Cerulli, R; Chernyak, D M; Danevich, F A; d'Angelo, S; Galashov, E N; Incicchitti, A; Kobychev, V V; Laubenstein, M; Mokina, V M; Poda, D V; Podviyanuk, R B; Polischuk, O G; Shlegel, V N; Stenin, Yu G; Suhonen, J; Tretyak, V I; Vasiliev, Ya V

    2011-01-01

    A search for the double beta processes in 106Cd was realized at the Gran Sasso National Laboratories of the INFN (Italy) with the help of a 106CdWO4 crystal scintillator (215 g) enriched in 106Cd up to 66%. After 6590 h of data taking, new improved half-life limits on the double beta processes in 106Cd were established at the level of 10^{19}-10^{21} yr; in particular, T_{1/2}(2\

  6. Chiral two-body currents in nuclei: Gamow-Teller transitions and neutrinoless double-beta decay

    Menéndez, J.; Gazit, D.; Schwenk, A.

    2011-01-01

    We show that chiral effective field theory (EFT) two-body currents provide important contributions to the quenching of low-momentum-transfer Gamow-Teller transitions, and use chiral EFT to predict the momentum-transfer dependence that is probed in neutrinoless double-beta decay. We then calculate for the first time the neutrinoless double-beta decay operator based on chiral EFT currents and study the nuclear matrix elements at successive orders. The contributions from chiral two-body currents...

  7. Double beta decay searches of Xe-134, Xe-126 and Xe-124 with large scale Xe detectors

    Barros, N; Zuber, K

    2014-01-01

    The sensitivity for double beta decay studies of Xe-134 and Xe-124 is investigated assuming a potential large scale Xe experiment developed for dark matter searches depleted in Xe-136. The opportunity for an observation of the 2nu double beta decay of Xe-134 is explored for various scenarios. A positive observation should be possible for all calculated nuclear matrix elements. The detection of 2$\

  8. Development of CaMoO4 crystal scintillators for double beta decay experiment with 100-Mo

    Annenkov, A.N.; Buzanov, O. A.; Danevich, F. A.; Georgadze, A. Sh.; Kim, S K; Kim, H. J.; Kim, Y.D.(Center for Underground Physics, Institute for Basic Science (IBS), Daejon, 305-811, Korea); Kobychev, V. V.; Kornoukhov, V.N.; Korzhik, M.; Lee, J. I.; Missevitch, O; Mokina, V. M.; S. S. Nagorny(INR Kiev); Nikolaiko, A. S.

    2007-01-01

    Energy resolution, alpha/beta ratio, pulse-shape discrimination for gamma rays and alpha particles, temperature dependence of scintillation properties, and radioactive contamination were studied with CaMoO4 crystal scintillators. A high sensitivity experiment to search for neutrinoless double beta decay of 100-Mo by using CaMoO4 scintillators is discussed.

  9. New Technique for Barium Daughter Ion Identification in a Liquid Xe-136 Double Beta Decay Experiment

    Fairbank, William [Colorado State Univ., Fort Collins, CO (United States)

    2016-06-08

    This work addresses long-standing issues of fundamental interest in elementary particle physics. The most important outcome of this work is a new limit on neutrinoless double beta decay. This is an extremely rare and long sought after type of radioactive decay. If discovered, it would require changes in the standard model of the elementary constituents of matter, and would prove that neutrinos and antineutrinos are the same, a revolutionary concept in particle physics. Neutrinos are major components of the matter in the universe that are so small and so weakly interacting with other matter that their masses have not yet been discovered. A discovery of neutrinoless double beta decay could help determine the neutrino masses. An important outcome of the work on this project was the Colorado State University role in operating the EXO-200 neutrinoless double beta decay experiment and in analysis of the data from this experiment. One type of double beta decay of the isotope 136Xe, the two-neutrino variety, was discovered in this work. Although the other type of double beta decay, the neutrinoless variety, was not yet discovered in this work, a world’s best sensitivity of 1.9x1025 year half-life was obtained. This result rules out a previous claim of a positive result in a different isotope. This work also establishes that the masses of the neutrinos, are less than one millionth of that of electrons. A unique EXO-200 analysis, in which the CSU group had a leading role, has established for the first time ever in a liquid noble gas the fraction of daughter atoms from alpha and beta decay that are ionized. This result has important impact on other pending studies, including nucleon decay and barium tagging. Novel additional discoveries include multiphoton ionization of liquid xenon with UV pulsed lasers, which may find application in calibration of future noble liquid detectors, and studies of association and dissociation reactions of Ba

  10. Signal and background studies for the search of neutrinoless double beta decay in GERDA

    Agostini, Matteo

    2013-04-24

    The GERDA experiment searches for the neutrinoless double beta decay in Ge-76, by operating bare HPGe detectors in ultra-pure liquid Ar. This dissertation presents a first decomposition of the background measured in the current data-taking phase. The background at the energy of interest was found to be dominated by {sup 214}Bi, {sup 208}Tl and {sup 42}K gamma-rays, with secondary contributions from {sup 42}K and {sup 214}Bi beta-rays, and {sup 210}Po alpha-rays. For the forthcoming upgrade of the apparatus, a new HPGe detector design (BEGe) has been studied, with focus on its capability of suppressing the identified backgrounds through pulse shape analysis. This included the development of a comprehensive modeling of the detectors and the experimental characterization of their response to surface interactions. The achieved results show that GERDA can improve the present limit on the neutrinoless double beta decay half-life by an order of magnitude.

  11. (d,p) reactions on 124Sn, 130Te, 138Ba, 140Ce, 142Nd, and 208Pb below and near the Coulomb barrier

    The reactions 124Sn(d,p)125Sn, 130Te(d,p)131Te, 138Ba(d,p)139Ba, 140Ce(d,p)141Ce, 142Nd(d,p)143Nd, and 208Pb(d,p)209Pb have been investigated by measuring the differential cross sections of the (d,p) reactions and of the elastic scattering of deuterons at various incident energies below and near the Coulomb barrier. Using scattering potentials which describe the elastic scattering of the particles in the entrance and exit channels, reduced normalizations of 40 final states have been determined which are nearly independent of the uncertainties due to the ambiguities of optical potentials. The experimental errors are 8% on the average. In the energy region studied the expected constancy of derived spectroscopic factors is demonstrated

  12. A separation method of 0ν- and 2ν-events in double beta decay experiments with DCBA

    A detector called Drift Chamber Beta-ray Analyzer (DCBA) will provide momentum information of each β-ray in double beta decay. The DCBA is expected to have good capabilities for particle identification, detection efficiency, background elimination and decay-source integration. Under the assumption of mass mechanism dominance in neutrinoless double beta decay, a simulation study shows that a combination method using both sum and single-energy distributions of double beta decay events can separate 0ν- and 2ν-events down to 0.05 eV of the effective neutrino mass with the help of a calculated nuclear matrix element, even though the DCBA has relatively poor energy resolution

  13. A scintillating bolometer array for double beta decay studies: The LUCIFER experiment

    Gironi, L.

    2016-07-01

    The main goal of the LUCIFER experiment is to study the neutrinoless double beta decay, a rare process allowed if neutrinos are Majorana particles. Although aiming at a discovery, in the case of insufficient sensitivity the LUCIFER technique will be the demonstrator for a higher mass experiment able to probe the entire inverted hierarchy region of the neutrino mass. In order to achieve this challenging result, high resolution detectors with active background discrimination capability are required. This very interesting possibility can be largely fulfilled by scintillating bolometers thanks to the simultaneous read-out of heat and light emitted by the interactions in the detector or by pulse shape analysis.

  14. Recent results of the IGEX 76Ge double-beta decay experiment

    The International Germanium Experiment (IGEX) has been analyzed 117 mol yr of data from its isotopical enriched (86% 76Ge) germanium detectors. Applying pulse-shape discrimination to the more recent data, the lower bound on the half-life for neutrinoless double-beta decay of 76Ge is deduced: T1/2(0ν) > 1.57 x 1025 ye (90% C.L.). This corresponds to an upper bound on the Majorana neutrino mass parameter, (mν), between 0.33 eV and 1.35 eV depending on the choice of theoretical nuclear matrix elements used in the analysis

  15. Neutrinoless double-beta decay search with CUORE and CUORE-0 experiments

    The Cryogenic Underground Observatory for Rare Events (CUORE) is an upcoming experiment designed to search for the neutrinoless double-beta decays. Observation of the process would unambiguously establish that neutrinos are Majorana particles and provide information on their absolute mass scale hierarchy. CUORE is now under construction and will consist of an array of 988 TeO2 crystal bolometers operated at 10 mK, but the first tower (CUORE-0) is already taking data. The experimental techniques used will be presented as well as the preliminary CUORE-0 results. The current status of the full-mass experiment and its expected sensitivity will then be discussed

  16. Beyond the SM ΔL=2 operators and neutrinoless double beta decay

    Neutrinoless double beta decay is a lepton number violating process (ΔL=2) whose observation would prove that neutrinos are Majorana particles, i.e. their own antiparticles. The simplest realisation of this process (mediation by light massive Majorana neutrinos) may however interfere with other lepton number violating operators. Therefore, the possibility to reliably extract neutrino parameters from the experimental results may be affected by this interplay. We discuss the effects of various beyond the SM ΔL=2 processes at higher scales on the measurement of the effective Majorana mass and their implications on different parameters in the neutrino sector.

  17. Search for neutrinoless double-beta decay of Ge-76 with GERDA

    Knoepfle, Karl-Tasso

    2008-01-01

    GERDA, the GERmanium Detector Array experiment, is a new double beta-decay experiment which is currently under construction in the INFN National Gran Sasso Laboratory (LNGS), Italy. It is implementing a new shielding concept by operating bare Ge diodes - enriched in Ge-76 - in high purity liquid argon supplemented by a water shield. The aim of GERDA is to verify or refute the recent claim of discovery, and, in a second phase, to achieve a two orders of magnitude lower background index than re...

  18. Results on neutrinoless double beta decay of 76Ge from GERDA Phase I

    Palioselitis, Dimitrios; GERDA Collaboration

    2015-05-01

    The Germanium Detector Array (GERDA) experiment is searching for the neutrinoless double beta (0νββ) decay of 76Ge by operating bare germanium diodes in liquid argon. GERDA is located at the Gran Sasso National Laboratory (LNGS) in Italy. During Phase I, a total exposure of 21.6 kg yrand a background index of 0.01 cts/(keVkg yr) were reached. No signal was observed and a lower limit of T0ν1/2 > 2.1 · 1025 yr(90% C.L.) is derived for the half life of the 0νββ decay of 76Ge.

  19. Search for neutrinoless double-beta decay of Ge-76 with GERDA

    Knoepfle, Karl-Tasso

    2008-01-01

    GERDA, the GERmanium Detector Array experiment, is a new double beta-decay experiment which is currently under construction in the INFN National Gran Sasso Laboratory (LNGS), Italy. It is implementing a new shielding concept by operating bare Ge diodes - enriched in Ge-76 - in high purity liquid argon supplemented by a water shield. The aim of GERDA is to verify or refute the recent claim of discovery, and, in a second phase, to achieve a two orders of magnitude lower background index than recent experiments. The paper discusses motivation, physics reach, design and status of construction of GERDA, and presents some R&D results.

  20. Limit on Neutrinoless Double Beta Decay of 76Ge by GERDA

    Agostini, M.; Allardt, M.; Andreotti, E.; Bakalyarov, A. M.; Balata, M.; Barabanov, I.; Heider, M. Barabè; Barros, N.; Baudis, L.; Bauer, C.; Becerici-Schmidt, N.; Bellotti, E.; Belogurov, S.; Belyaev, S. T.; Benato, G.; Bettini, A.; Bezrukov, L.; Bode, T.; Brudanin, V.; Brugnera, R.; Budjáš, D.; Caldwell, A.; Cattadori, C.; Chernogorov, A.; Cossavella, F.; Demidova, E. V.; Domula, A.; Egorov, V.; Falkenstein, R.; Ferella, A.; Freund, K.; Frodyma, N.; Gangapshev, A.; Garfagnini, A.; Gotti, C.; Grabmayr, P.; Gurentsov, V.; Gusev, K.; Guthikonda, K. K.; Hampel, W.; Hegai, A.; Heisel, M.; Hemmer, S.; Heusser, G.; Hofmann, W.; Hult, M.; Inzhechik, L. V.; Csáthy, J. Janicskó; Jochum, J.; Junker, M.; Kihm, T.; Kirpichnikov, I. V.; Kirsch, A.; Klimenko, A.; Knöpfle, K. T.; Kochetov, O.; Kornoukhov, V. N.; Kuzminov, V. V.; Laubenstein, M.; Lazzaro, A.; Lebedev, V. I.; Lehnert, B.; Liao, H. Y.; Lindner, M.; Lippi, I.; Lubashevskiy, A.; Lubsandorzhiev, B.; Lutter, G.; Machado, A. A.; Macolino, C.; Majorovits, B.; Maneschg, W.; Misiaszek, M.; Nemchenok, I.; Nisi, S.; Shaughnessy, C. O.'.; Pandola, L.; Pelczar, K.; Pessina, G.; Pullia, A.; Riboldi, S.; Rumyantseva, N.; Sada, C.; Salathe, M.; Schmitt, C.; Schreiner, J.; Schulz, O.; Schwingenheuer, B.; Schönert, S.; Shevchik, E.; Shirchenko, M.; Simgen, H.; Smolnikov, A.; Stanco, L.; Strecker, H.; Tarka, M.; Ur, C. A.; Vasenko, A. A.; Volynets, O.; von Sturm, K.; Wagner, V.; Walter, M.; Wegmann, A.; Wester, T.; Wojcik, M.; Yanovich, E.; Zavarise, P.; Zhitnikov, I.; Zhukov, S. V.; Zinatulina, D.; Zuber, K.; Zuzel, G.

    The Gerda experiment at the Laboratori Nazionali del Gran Sasso in Italy uses germanium detectors made from material with an enriched 76Ge isotope fraction to search for neutrinoless double beta decay of this nucleus. Applying a blind analysis we find no signal after an exposure of 21.6 kg·yr and a background of about 0.01 cts/(keV·kg·yr). A half-life limit of Tov1/2> 2.1 · 1025 yr (90% C.L.) is extracted. The previous claim of a signal for 76Ge is excluded with 99% probability in a model independent way.

  1. Double Beta Decay and Dark Matter Search - Window to New Physics now, and in future (GENIUS)

    Klapdor-Kleingrothaus, H. V.

    1998-01-01

    Nuclear double beta decay provides an extraordinarily broad potential to search for beyond Standard Model physics, probing already now the TeV scale, on which new physics should manifest itself. These possibilities are reviewed here. First, the results of present generation experiments are presented. The most sensitive one of them -- the Heidelberg-Moscow experiment in the Gran Sasso -- probes the electron mass now in the sub eV region and will reach a limit of $\\sim$ 0.1 eV in a few years. B...

  2. The double beta decay spectrum of 100Mo as measured with a TPC [time projection chamber

    A time projection chamber with 8.3 grams of enriched 100MoO3 as the central electrode has been operating approximately five months in an underground laboratory. A preliminary analysis of the two-electron sum energy spectrum, the spectrum of those same electrons taken singly, and the opening angle distribution yields a half life of 1.16-0.08+0.34 x 1019 y at the 68% confidence level for two-neutrino double beta decay of 100Mo. 9 refs., 8 figs

  3. AXEL: High pressure xenon gas Time Projection Chamber for neutrinoless double beta decay search

    Pan, Sheng

    2016-05-01

    AXEL is a high pressure xenon gas TPC detector being developed for neutrinoless double-beta decay search. We use proportional scintillation mode with a new electroluminescence light detection scheme to achieve very high energy resolution with a large detector. The detector has a capability of tracking which can be used reduce background. The project is in a R&D phase, and we report current status of our prototype chamber with 10 L and 8 bar Xe gas. We also present the results of the photon detection efficiency measurement and the linearity test of silicon photomultiplier(SiPM).

  4. Neutrinoless double-beta decay search with CUORE and CUORE-0 experiments

    Moggi, N.; Artusa, D. R.; Avignone, F. T.; Azzolini, O.; Balata, M.; Banks, T. I.; Bari, G.; Beeman, J.; Bellini, F.; Bersani, A.; Biassoni, M.; Brofferio, C.; Bucci, C.; Cai, X. Z.; Camacho, A.; Caminata, A.; Canonica, L.; Cao, X. G.; Capelli, S.; Cappelli, L.; Carbone, L.; Cardani, L.; Casali, N.; Cassina, L.; Chiesa, D.; Chott, N.; Clemenza, M.; Copello, S.; Cosmelli, C.; Cremonesi, O.; Creswick, R. J.; Cushman, J. S.; Dafinei, I.; Dally, A.; Datskov, V.; Dell'oro, S.; Deninno, M. M.; Di Domizio, S.; Di Vacri, M. L.; Drobizhev, A.; Ejzak, L.; Fang, D. Q.; Farach, H. A.; Faverzani, M.; Fernandes, G.; Ferri, E.; Ferroni, F.; Fiorini, E.; Franceschi, M. A.; Freedman, S. J.; Fujikawa, B. K.; Giachero, A.; Gironi, L.; Giuliani, A.; Gorla, P.; Gotti, C.; Gutierrez, T. D.; Haller, E. E.; Han, K.; Heeger, K. M.; Hennings-Yeomans, R.; Hickerson, K. P.; Huang, H. Z.; Kadel, R.; Keppel, G.; Kolomensky, Yu. G.; Li, Y. L.; Ligi, C.; Lim, K. E.; Liu, X.; Ma, Y. G.; Maiano, C.; Maino, M.; Martinez, M.; Maruyama, R. H.; Mei, Y.; Morganti, S.; Napolitano, T.; Nisi, S.; Nones, C.; Norman, E. B.; Nucciotti, A.; O'Donnell, T.; Orio, F.; Orlandi, D.; Ouellet, J. L.; Pagliarone, C. E.; Pallavicini, M.; Palmieri, V.; Pattavina, L.; Pavan, M.; Pessina, G.; Pettinacci, V.; Piperno, G.; Pira, C.; Pirro, S.; Pozzi, S.; Previtali, E.; Rosenfeld, C.; Rusconi, C.; Sala, E.; Sangiorgio, S.; Santone, D.; Scielzo, N. D.; Sisti, M.; Smith, A. R.; Taffarello, L.; Tenconi, M.; Terranova, F.; Tian, W. D.; Tomei, C.; Trentalange, S.; Ventura, G.; Vignati, M.; Wang, B. S.; Wang, H. W.; Wielgus, L.; Wilson, J.; Winslow, L. A.; Wise, T.; Woodcraft, A.; Zanotti, L.; Zarra, C.; Zhang, G. Q.; Zhu, B. X.; Zucchelli, S.

    2015-03-01

    The Cryogenic Underground Observatory for Rare Events (CUORE) is an upcoming experiment designed to search for the neutrinoless double-beta decays. Observation of the process would unambiguously establish that neutrinos are Majorana particles and provide information on their absolute mass scale hierarchy. CUORE is now under construction and will consist of an array of 988 TeO2 crystal bolometers operated at 10 mK, but the first tower (CUORE-0) is already taking data. The experimental techniques used will be presented as well as the preliminary CUORE-0 results. The current status of the full-mass experiment and its expected sensitivity will then be discussed.

  5. Neutrinoless double-beta decay search with CUORE and CUORE-0 experiments

    Moggi N.

    2015-01-01

    Full Text Available The Cryogenic Underground Observatory for Rare Events (CUORE is an upcoming experiment designed to search for the neutrinoless double-beta decays. Observation of the process would unambiguously establish that neutrinos are Majorana particles and provide information on their absolute mass scale hierarchy. CUORE is now under construction and will consist of an array of 988 TeO2 crystal bolometers operated at 10 mK, but the first tower (CUORE-0 is already taking data. The experimental techniques used will be presented as well as the preliminary CUORE-0 results. The current status of the full-mass experiment and its expected sensitivity will then be discussed.

  6. Progress in the use of pixel detectors in double beta decay experiment TGV

    The TGV collaboration has been investigating two neutrino double electron capture (2νEC/EC) in 106Cd since 2000. The double beta experiments would answer some of the puzzling problems about neutrinos (e.g. nature and mass) but one of the main challenges is the background events. The collaboration is investigating the use of pixel detectors in such rare decay experiments. Pixel detector gives spatial information along with energy of the particle, thus provides useful information to reduce the background. The collaboration has proposed a Silicon Pixel Telescope (SPT) for the next generation experiment; where a pair of Si pixel detectors with enriched Cd foil in the middle forms the detection unit. A prototype unit of SPT has been constructed and results of preliminary background measurements performed on the surface and in the underground laboratories are presented

  7. Progress in the use of pixel detectors in double beta decay experiment TGV

    Jose, J. M.; TGV Collaboration

    2013-12-01

    The TGV collaboration has been investigating two neutrino double electron capture (2νEC/EC) in 106Cd since 2000. The double beta experiments would answer some of the puzzling problems about neutrinos (e.g. nature and mass) but one of the main challenges is the background events. The collaboration is investigating the use of pixel detectors in such rare decay experiments. Pixel detector gives spatial information along with energy of the particle, thus provides useful information to reduce the background. The collaboration has proposed a Silicon Pixel Telescope (SPT) for the next generation experiment; where a pair of Si pixel detectors with enriched Cd foil in the middle forms the detection unit. A prototype unit of SPT has been constructed and results of preliminary background measurements performed on the surface and in the underground laboratories are presented.

  8. Progress in the use of pixel detectors in double beta decay experiment TGV

    Jose, J. M. [Institute of Experimental and Applied Physics, Czech Technical University in Prague, Horska 3a/22, 12800 Prague 2 (Czech Republic); Collaboration: TGV Collaboration

    2013-12-30

    The TGV collaboration has been investigating two neutrino double electron capture (2νEC/EC) in {sup 106}Cd since 2000. The double beta experiments would answer some of the puzzling problems about neutrinos (e.g. nature and mass) but one of the main challenges is the background events. The collaboration is investigating the use of pixel detectors in such rare decay experiments. Pixel detector gives spatial information along with energy of the particle, thus provides useful information to reduce the background. The collaboration has proposed a Silicon Pixel Telescope (SPT) for the next generation experiment; where a pair of Si pixel detectors with enriched Cd foil in the middle forms the detection unit. A prototype unit of SPT has been constructed and results of preliminary background measurements performed on the surface and in the underground laboratories are presented.

  9. Measurement and analysis of excitation functions of radioactive nuclide produced in the interaction of 16O + 130Te system over the energy range 3.8 - 5.6 MeV/A

    In this work as part of a program to study complete fusion (CF), incomplete fusion (ICF) and pre-equilibrium (PE) emission in heavy ion induced reactions, activation technique has been used to measure the EFs for radionuclide populated in the interaction of 16O + 130Te system in the energy range ≅ 61 to 90 MeV

  10. Sensitivity of future liquid xenon experiments to the detection of double-beta decays of xenon

    Dark searches are one of the most active fields of physics in the recent years. A new generation of experiments using liquid xenon as active medium are currently under investigation to further increase the sensitivity. These will exceed the present limit of 1 t active mass. This development will allow to reach unprecedented sensitivities not only for dark matter searches, but also for half-life measurements of long living isotopes of xenon. Xenon itself has three candidates for double-beta decay, but only the 2nbb decay of 136Xe has been measured with a half-life of T1/2 = (2.38±0.11±0.05) x 1021 yr. In this talk studies of sensitivities for the detection of the yet unobserved remaining double beta decay modes of xenon by this new generation of experiments will be presented. A particular emphasis on the sensitivity for a measurement of the half-life of 134Xe will be performed, assuming different background models.

  11. GERDA and the search for neutrinoless double beta decay: first results and perspectives

    Neutrinoless double beta decay is a lepton-number-violating nuclear transition predicted by several extensions of the Standard Model. The Gerda experiment searches for this transition in 76Ge by operating bare Ge detectors in liquid Ar. The talk focuses on the results of data acquired during Phase I of the experiment, in which 21.6 kg.yr of exposure were accumulated with a background index of about 0.01 cts/(keV.kg.yr). No signal was observed and a lower limit was derived for the half-life of neutrinoless double beta decay of 76Ge, T1/2 > 2.1 . 1025 yr (90% C.L.). The experiment is currently undergoing a major upgrade in preparation for the next phase of data taking. Thanks to an increased target mass, an improved energy resolution and the introduction of novel background reduction techniques, the sensitivity of Gerda will increase of about one order of magnitude in a few years of operation.

  12. GERDA and the search for neutrinoless double beta decay: first results and perspectives

    Agostini, Matteo [Physik Department and Excellence Cluster Universe, Technische Universitaet Muenchen (Germany); Collaboration: GERDA-Collaboration

    2014-07-01

    Neutrinoless double beta decay is a lepton-number-violating nuclear transition predicted by several extensions of the Standard Model. The Gerda experiment searches for this transition in {sup 76}Ge by operating bare Ge detectors in liquid Ar. The talk focuses on the results of data acquired during Phase I of the experiment, in which 21.6 kg.yr of exposure were accumulated with a background index of about 0.01 cts/(keV.kg.yr). No signal was observed and a lower limit was derived for the half-life of neutrinoless double beta decay of {sup 76}Ge, T{sub 1/2} > 2.1 . 10{sup 25} yr (90% C.L.). The experiment is currently undergoing a major upgrade in preparation for the next phase of data taking. Thanks to an increased target mass, an improved energy resolution and the introduction of novel background reduction techniques, the sensitivity of Gerda will increase of about one order of magnitude in a few years of operation.

  13. Search for double beta decay with HPGe detectors at the Gran Sasso underground laboratory

    Chkvorets, Oleg

    2008-01-01

    Neutrinoless double-beta decay is practically the only way to establish the Majorana nature of the neutrino mass and its decay rate provides a probe of an effective neutrino mass. Double beta experiments are long-running underground experiments with specific challenges concerning the background reduction and the long term stability. These problems are addressed in this work for the Heidelberg-Moscow (HdM), GENIUS Test Facility (TF) and GERDA experiments. The HdM experiment collected data with enriched 76Ge high purity (HPGe) detectors from 1990 to 2003. An improved analysis of HdM data is presented, exploiting new calibration and spectral shape measurements with the HdM detectors. GENIUS-TF was a test-facility that verified the feasibility of using bare germanium detectors in liquid nitrogen. The first year results of this experiment are discussed. The GERDA experiment has been designed to further increase the sensitivity by operating bare germanium detectors in a high purity cryogenic liquid, which simultane...

  14. Search for neutrinoless double beta decay of Ge-76 with the GERmanium Detector Array '' GERDA ''

    The study of neutrinoless double beta decay (DBD) is the most powerful approach to the fundamental question if the neutrino is a Majorana particle, i.e. its own anti-particle. The observation of neutrinoless DBD would not only establish the Majorana nature of the neutrino but also represent a determination of its effective mass if the nuclear matrix element is given. So far, the most sensitive results have been obtained with Ge-76, and the group of Klapdor-Kleingrothaus has made a claim of discovery. Future experiments have to reduce radioactive backgrounds to increase the sensitivity. '' GERDA '' is a new double beta-decay experiment which is currently under construction in the INFN Gran Sasso National Laboratory, Italy. It is implementing a new shielding concept by operating bare Ge diodes - enriched in Ge-76 - in high purity liquid argon supplemented by a water shield. The aim of '' GERDA '' is to verify or refute the recent claim of discovery, and, in a second phase, to achieve a two orders of magnitude lower background index than recent experiments, increasing the sensitive mass and reaching exposure of 100 kg yr. It be will discuss design, physics reach, and status of construction of '' GERDA '', and present results from various R efforts including long term stability of bare Ge diodes in cryogenic liquids, material screening, cryostat performance, detector segmentation, cryogenic precision electronics, safety aspects, and Monte Carlo simulations. (author)

  15. Status and future prospect of 48Ca double beta decay search in CANDLES

    Iida, T.; Nakajima, K.; Ajimura, S.; Batpurev, T.; Chan, W. M.; Fushimi, K.; Hazama, R.; Kakubata, H.; Khai, B. T.; Kishimoto, T.; Li, X.; Maeda, T.; Masuda, A.; Matsuoka, K.; Morishita, K.; Nakatani, N.; Nomachi, M.; Noshiro, S.; Ogawa, I.; Ohata, T.; Osumi, H.; Suzuki, K.; Tamagawa, Y.; Tesuno, K.; Trang, V. T. T.; Uehara, T.; Umehara, S.; Yoshida, S.

    2016-05-01

    The observation of neutrino-less double beta decay (0vßß) would be the most practical way to prove the Majorana nature of the neutrino and lepton number violation. CANDLES studies 48Ca double beta decay using CaF2 scintillator. The main advantage of 48Ca is that it has the highest Q-value (4.27 MeV) among all the isotope candidates for 0vßß. The CANDLES III detector is currently operating with 300kg CaF2 crystals in the Kamioka underground observatory, Japan. In 2014, a detector cooling system and a magnetic cancellation coil was installed with the aim to increase light emission of CaF2 scintillator and photo-electron collection efficiency of the photo-multipliers. After this upgrade, light yield was increased to 1000 p.e./MeV which is 1.6 times larger than before. According to data analysis and simulation, main background source in CANDLES is turned out to be high energy external gamma-ray originating neutron capture on the surrounding materials, so called (n,γ). Upgrading the detector by installing neutron and gamma-ray shield can reduce the remaining main backgrounds by two order magnitude. In this report, we discuss the detail of (n,γ) and background reduction by additional shielding.

  16. Nuclear Double Beta Decay, Fundamental Particle Physics, Hot Dark Matter, And Dark Energy

    Klapdor-Kleingrothaus, Hans Volker

    2010-01-01

    Nuclear double beta decay, an extremely rare radioactive decay process, is - in one of its variants - one of the most exciting means of research into particle physics beyond the standard model. The large progress in sensitivity of experiments searching for neutrinoless double beta decay in the last two decades - based largely on the use of large amounts of enriched source material in "active source experiments" - has lead to the observation of the occurrence of this process in nature (on a 6.4 sigma level), with the largest half-life ever observed for a nuclear decay process (2.2 x 10^{25} y). This has fundamental consequences for particle physics - violation of lepton number, Majorana nature of the neutrino. These results are independent of any information on nuclear matrix elements (NME)*. It further leads to sharp restrictions for SUSY theories, sneutrino mass, right-handed W-boson mass, superheavy neutrino masses, compositeness, leptoquarks, violation of Lorentz invariance and equivalence principle in the...

  17. Double beta decay - physics beyond the standard model now, and in future (Genius)

    Nuclear double beta decay provides an extraordinarily broad potential to search for beyond standard model physics, probing already now the TeV scale, on which new physics should manifest itself. These possibilities are reviewed here. First, the results of present generation experiments are presented. The most sensitive one of them - the Heidelberg-Moscow experiment in the Gran Sasso - probes the electron mass now in the sub eV region and will reach a limit of ∝0.1 eV in a few years. Basing to a large extent on the theoretical work of the Heidelberg double beta group in the last two years, results are obtained also for SUSY models (R-parity breaking, sneutrino mass), leptoquarks (leptoquark-Higgs coupling), compositeness, right-handed W boson mass and others. These results are comfortably competitive to corresponding results from high-energy accelerators like TEVATRON, HERA, etc. Second, future perspectives of ββ research are discussed. A new Heidelberg experimental proposal (GENIUS) is presented which would allow to increase the sensitivity for Majorana neutrino masses from the present level of at best 0.1 eV down to 0.01 or even 0.001 eV. Its physical potential would be a breakthrough into the multi-TeV range for many beyond standard models. Its sensitivity for neutrino oscillation parameters would be larger than of all present terrestrial neutrino oscillation experiments and of those planned for the future. (orig.)

  18. Status Update of the MAJORANA DEMONSTRATOR Neutrinoless Double Beta Decay Experiment

    Gruszko, Julieta; Arnquist, Isaac; Avignone, Frank; Barabash, Alexander; Bertrand, Fred; Bradley, Adam; Brudanin, Viktor; Busch, Matthew; Buuck, Micah; Byram, Dana; Caldwell, Adam; Chan, Yuen-Dat; Christofferson, Cabot-Ann; Chu, Pinghan; Cuesta, Clara; Detwiler, Jason; Dunagan, Colter; Efremenko, Yuri; Ejiri, Hiroyasu; Elliott, Steven; Galindo-Uribarri, Alfredo; Gilliss, Tom; Giovanetti, Graham K; Goett, Johnny; Green, Matthew P; Guinn, Ian; Guiseppe, Vince; Henning, Reyco; Hoppe, Eric; Howard, Stanley; Howe, Mark; Jasinski, Ben; Keeter, Kara; Kidd, Mary; Konovalov, Sergey; Kouzes, Richard T; LaFerriere, Brian; Leon, Jonathan; MacMullin, Jacqueline; Martin, Ryan; Massarczyk, Ralph; Meijer, Sam; Mertens, Susanne; OShaughnessy, Christopher; Orrell, John; Poon, Alan; Radford, David; Rager, Jamin; Rielage, Keith; Robertson, R G Hamish; Romero-Romero, Elisa; Shanks, Benjamin; Shirchenko, Mark; Snyder, Nathan; Suriano, Anne-Marie; Tedeschi, David; Trimble, Jim; Varner, Robert; Vasilyev, Sergey; Vetter, Kai; Vorren, Kris; White, Brandon; Wilkerson, John F; Wiseman, Clint; Xu, Wenqin; Yakushev, E; Yu, Chang-Hong; Yumatov, Vladimir; Zhitnikov, Igor

    2015-01-01

    Neutrinoless double beta decay searches play a major role in determining neutrino properties, in particular the Majorana or Dirac nature of the neutrino and the absolute scale of the neutrino mass. The consequences of these searches go beyond neutrino physics, with implications for Grand Unification and leptogenesis. The \\textsc{Majorana} Collaboration is assembling a low-background array of high purity Germanium (HPGe) detectors to search for neutrinoless double-beta decay in $^{76}$Ge. The \\textsc{Majorana Demonstrator}, which is currently being constructed and commissioned at the Sanford Underground Research Facility in Lead, South Dakota, will contain 44 kg (30 kg enriched in $^{76}$Ge) of HPGe detectors. Its primary goal is to demonstrate the scalability and background required for a tonne-scale Ge experiment. This is accomplished via a modular design and projected background of less than 3 cnts/tonne-yr in the region of interest. The experiment is currently taking data with the first of its enriched det...

  19. New physics effects on neutrinoless double beta decay from right-handed current

    Ge, Shao-Feng; Patra, Sudhanwa

    2015-01-01

    We study the impact of new physics contributions to neutrinoless double beta decay arising from right-handed current in comparison with the standard mechanism. If the light neutrinos obtain their masses from Type-II seesaw within left-right symmetric model, where the Type-I contribution is suppressed to negligible extent, the right-handed PMNS matrix is the same as its left-handed counterpart, making it highly predictable and can be tested at next-generation experiments. It is very attractive, especially with recent cosmological constraint favoring the normal hierarchy under which the neutrinoless double beta decay is too small to be observed unless new physics appears as indicated by the recent diboson excess observed at ATLAS. The relative contributions from left- and right-handed currents can be reconstructed with the ratio between lifetimes of two different isotopes as well as the ratio of nuclear matrix elements. In this way, the theoretical uncertainties in the calculation of nuclear matrix elements can...

  20. Status Update of the Majorana Demonstrator Neutrinoless Double Beta Decay Experiment

    Gruzko, Julieta [Univ. of Washington, Seattle, WA (United States); Rielage, Keith Robert [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Xu, Wenqin [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Elliott, Steven Ray [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Massarczyk, Ralph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Goett, John Jerome III [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Chu, Pinghan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-11-10

    Neutrinoless double beta decay searches play a major role in determining neutrino properties, in particular the Majorana or Dirac nature of the neutrino and the absolute scale of the neutrino mass. The consequences of these searches go beyond neutrino physics, with implications for Grand Unification and leptogenesis. The Majorana Collaboration is assembling a low-background array of high purity Germanium (HPGe) detectors to search for neutrinoless double-beta decay in 76Ge. The Majorana Demonstrator, which is currently being constructed and commissioned at the Sanford Underground Research Facility in Lead, South Dakota, will contain 44 kg (30 kg enriched in 76Ge) of HPGe detectors. Its primary goal is to demonstrate the scalability and background required for a tonne-scale Ge experiment. This is accomplished via a modular design and projected background of less than 3 cnts/tonne-yr in the region of interest. The experiment is currently taking data with the first of its enriched detectors.

  1. Neutrinoless double $\\beta$ decay in Supersymmetry with bilinear R-parity breaking

    Hirsch, M

    1999-01-01

    We reanalyze the contributions to neutrinoless double beta ($\\znbb$) decay from supersymmetry with explicit breaking of R-parity. Although we keep both bilinear and trilinear terms, our emphasis is put on bilinear R-parity breaking terms, because these mimic more closely the models where the breaking of R-parity is spontaneous. Comparing the relevant Feynman diagrams we conclude that the usual mass mechanism of double beta decay is the dominant one. From the non-observation of $\\znbb$ decay we set limits on the bilinear R-parity breaking parameters of typically a (few) 100 $keV$. Despite such stringent bounds, we stress that the magnitude of R-parity violating phenomena that can be expected at accelerator experiments can be very large, since they involve mainly the third generation, while $\\znbb$ decay constrains only the first generation couplings. We find that even in the limit when neutrinos are massless at tree-level, $\\znbb$ decay gives useful constraints on bilinear parameters through the finite neutral...

  2. Searching for the Dirac Nature of Neutrinos: Combining Neutrinoless Double Beta Decay and Neutrino Mass Measurements

    We studied the neutrinoless double beta decay process to tackle the issue about the nature of neutrino. Establishing the nature of neutrinos, whether they are Dirac or Majorana particles is one of the fundamental questions we need to answer in particle physics, and is related to the conservation of lepton number. Neutrinoless double beta decay ((ββ)0ν) is the tool of choice for testing the Majorana nature of neutrinos. However, up to now, this process has not been observed, but a wide experimental effort is taking place worldwide and soon new results will become available. Different mechanisms can induce (ββ)0ν-decay and might interfere with each other, potentially leading to suppressed contributions to the decay rate. This possibility would become of great interest if upcoming neutrino mass measurements from KATRIN and cosmological observations found that mν>0.2eV but no positive signal was observed in (ββ)0ν-decay experiments. We focus on the possible interference between light Majorana neutrino exchange with other mechanisms, such as heavy sterile neutrinos and R-parity violating supersymmetric models. We show that in some cases the use of different nuclei would allow to disentangle the different contributions and allow to test the hypothesis of destructive interference. Finally, we present a model in which such interference can emerge and we discuss the range of parameters which would lead to a significant suppression of the decay rate

  3. The AMoRE: Search for neutrinoless double beta decay of {sup 100}Mo

    Park, HyangKyu, E-mail: hkpark@ibs.re.kr [Center for Underground Physics, Institute for Basic Science (IBS), Daejeon 305-811 (Korea, Republic of)

    2015-10-28

    The AMoRE (Advanced Mo-based Rare process Experiment) collaboration is using calcium molybdate ({sup dep48}Ca {sup 100}MoO{sub 4}) crystals enriched in {sup 100}Mo and depleted in {sup 48}Ca to search for neutrinoless double-beta decay (DBD) of {sup 100}Mo using at the underground laboratory in Korea. Metallic magnetic calorimeters operating a milliKelvin temperatures are used as temperature sensors to measure heat and light signals from the crystals. The simultaneous and fast detection capabilities for both phonons and photons, and their excellent energy resolution provide powerful methods for identifying DBD signals and rejecting background events, which are mainly due to random coincidences between two uncorrelated two-neutrino-double-beta decays of {sup 100}Mo. The AMoRE-Pilot experiment that is currently underway uses a 1.5 kg, five-element array of {sup dep48}Ca {sup 100}MoO{sub 4} crystals. The ultimate goal is a ∼200 kg array of crystals and a half-life sensitivity of order 10{sup 26} years, which will access the inverted hierarchy region for effective Majorana neutrino masses, i.e., 0.02 to 0.05 eV. In this talk, we present recent progress on the development of low-background calcium molybdate detectors and results from room- and milli-Kelvin temperatures. Sensitivities based on GEANT4 simulations that incorporate measured background are reported.

  4. Single Molecule Fluorescence Imaging as a Technique for Barium Tagging in Neutrinoless Double Beta Decay

    Jones, B J P; Nygren, D R

    2016-01-01

    Background rejection is key to success for future neutrinoless double beta decay experiments. To achieve sensitivity to effective Majorana lifetimes of $\\sim10^{28}$ years, backgrounds must be controlled to better than 0.1 count per ton per year, beyond the reach of any present technology. In this paper we propose a new method to identify the birth of the barium daughter ion in the neutrinoless double beta decay of $^{136}$Xe. The method adapts Single Molecule Fluorescent Imaging, a technique from biochemistry research with demonstrated single ion sensitivity. We explore possible SMFI dyes suitable for the problem of barium ion detection in high pressure xenon gas, and develop a fiber-coupled sensing system with which we can detect the presence of bulk Ba$^{++}$ ions remotely. We show that our sensor produces signal-to-background ratios as high as 85 in response to Ba$^{++}$ ions when operated in aqueous solution. We then describe the next stage of this R\\&D program, which will be to demonstrate chelation...

  5. First Direct Double-Beta Decay Q-value Measurement of 82Se in Support of Understanding the Nature of the Neutrino

    Lincoln, David L; Bollen, Georg; Brodeur, Maxime; Bustabad, Scott; Engel, Jonathan; Novario, Samuel J; Redshaw, Matthew; Ringle, Ryan; Schwarz, Stefan

    2012-01-01

    In anticipation of results from current and future double-beta decay studies, we report a measurement resulting in a 82Se double-beta decay Q-value of 2997.9(3) keV, an order of magnitude more precise than the currently accepted value. We also present preliminary results of a calculation of the 82Se neutrinoless double-beta decay nuclear matrix element that corrects in part for the small size of the shell model single-particle space. The results of this work are important for designing next generation double-beta decay experiments and for the theoretical interpretations of their observations.

  6. Search for double beta decay of $^{116}$Cd with enriched $^{116}$CdWO$_4$ crystal scintillators (Aurora experiment)

    Danevich, F A; Belli, P; Bernabei, R; Cappella, F; Caracciolo, V; Cerulli, R; Chernyak, D M; d'Angelo, S; Incicchitti, A; Kobychev, V V; Konovalov, S I; Laubenstein, M; Mokina, V M; Poda, D V; Polischuk, O G; Shlegel, V N; Tretyak, V I; Umatov, V I

    2016-01-01

    The Aurora experiment to investigate double beta decay of $^{116}$Cd with the help of 1.162 kg cadmium tungstate crystal scintillators enriched in $^{116}$Cd to 82\\% is in progress at the Gran Sasso Underground Laboratory. The half-life of $^{116}$Cd relatively to the two neutrino double beta decay is measured with the highest up-to-date accuracy $T_{1/2}=(2.62\\pm0.14)\\times10^{19}$ yr. The sensitivity of the experiment to the neutrinoless double beta decay of $^{116}$Cd to the ground state of $^{116}$Sn is estimated as $T_{1/2} \\geq 1.9\\times10^{23}$ yr at 90\\% CL, which corresponds to the effective Majorana neutrino mass limit $\\langle m_{\

  7. A high-resolution CMOS imaging detector for the search of neutrinoless double beta decay in $^{82}$Se

    Chavarria, A E; Li, X; Rowlands, J A

    2016-01-01

    We introduce a new technology of detectors for the search of the neutrinoless double beta decay of $^{82}$Se. Based on the present literature, imaging devices from amorphous $^{82}$Se evaporated on a complementary metal-oxide-semiconductor (CMOS) active pixel array are expected to have the energy and spatial resolution to produce two-dimensional images of ionizing tracks of utmost quality, effectively akin to an electronic bubble chamber in the double beta decay energy regime. Still to be experimentally demonstrated, a detector consisting of a large array of these devices could have very low backgrounds, possibly reaching $10^{-7}$/(kg y) in the neutrinoless decay region of interest (ROI), as it may be required for the full exploration of the neutrinoless double beta decay parameter space in the most unfavorable condition of a strongly quenched nucleon axial coupling constant.

  8. Measurement of the Double-Beta Decay Half-life of {sup 136}Xe in KamLAND-Zen

    KamLAND-Zen Collaboration; Gando, A.; Gando, Y.; Hanakago, H.; Ikeda, H.; Inoue, K.; Kato, R.; Koga, M.; Matsuda, S.; Mitsui, T.; Nakada, T.; Nakamura, K.; Obata, A.; Oki, A.; Ono, Y.; Shimizu, I.; Shirai, J.; Suzuki, A.; Takemoto, Y.; Tamae, K.; Ueshima, K.; Watanabe, H.; Xu, B. D.; Yamada, S.; Yoshida, H.; Kozlov, A.; Yoshida, S.; Banks, T. I.; Detwiler, J. A.; Freedman, S. J.; Fujikawa, B. K.; Han, K.; O& #x27; Donnell, T.; Berger, B. E.; Efremenko, Y.; Karwowski, H. J.; Markoff, D. M.; Tornow, W.; Enomoto, S.; Decowski, M. P.

    2012-01-23

    We present results from the KamLAND-Zen double-beta decay experiment based on an exposure of 77.6 days with 129 kg of {sup 136}Xe. The measured two-neutrino double-beta decay half-life of {sup 136}Xe is T{sup 2{nu}}{sub 1/2} = 2:38 {+-} 0:02(stat) {+-}0.14(syst) x10{sup 21} yr, consistent with a recent measurement by EXO-200. We also obtain a lower limit for the neutrinoless double-beta decay half-life, T{sup 0{nu}}{sub 1/2} > 5.7 x 10{sup 24} yr at 90% C.L.

  9. Ba-ion extraction from a high pressure Xe gas for double-beta decay studies with EXO

    Brunner, T; Sabourov, A; Varentsov, V L; Gratta, G; Sinclair, D

    2013-01-01

    An experimental setup is being developed to extract Ba ions from a high-pressure Xe gas environment. It aims to transport Ba ions from 10 bar Xe to vacuum conditions. The setup utilizes a converging-diverging nozzle in combination with a radio-frequency (RF) funnel to move Ba ions into vacuum through the pressure drop of several orders of magnitude. This technique is intended to be used in a future multi-ton detector investigating double-beta decay in $^{136}$Xe. Efficient extraction and detection of Ba ions, the decay product of Xe, would allow for a background-free measurement of the $^{136}$Xe double-beta decay.

  10. The Potential of Hybrid Pixel Detectors in the Search for the Neutrinoless Double-Beta Decay of Cd-116

    Michel, Thilo; Gleixner, Thomas; Durst, Jürgen; Filipenko, Mykhaylo; Geisselsoeder, Stefan

    2013-01-01

    We investigated the potential of the energy resolving hybrid pixel detector Timepix contacted to a CdTe sensor layer for the search for the neutrinoless double-beta decay of Cd-116. We found that a CdTe sensor layer with 3 mm thickness and 165 mu m pixel pitch is optimal with respect to the effective Majorana neutrino mass (m(beta beta)) sensitivity. In simulations, we were able to demonstrate a possible reduction of the background level caused by single electrons by approximately 75% at a sp...

  11. Majorana Neutrinos, Neutrino Mass Spectrum and the || ~ 0.001 eV Frontier in Neutrinoless Double Beta Decay

    Pascoli, S.; Petcov, S.T.

    2007-01-01

    If future neutrino oscillation experiments show that the neutrino mass spectrum is with normal ordering, m1 0.01 eV give negative results, the next frontier in the quest for neutrinoless double beta-decay will correspond to || ~ 0.001 eV. Assuming that massive neutrinos are Majorana particles and their exchange is the dominant mechanism generating neutrinoless double b...

  12. Double beta radioactivity and physics of the neutrino. Study of the background noise at 3 MeV in the search of 100Mo beta beta decay

    Double beta decay without neutrino emission provides a test of the mass and nature of neutrinos (Majorana or Dirac). Experimental proof would be the observation of a peak at the transition energy in the spectrum of the two emitted electrons. The expected half-life of the process is extremely long (about 1025 years for 100Mo). So, being thus, it is very important to get a good knowledge of the origins and contributions of background noise in the region where the signal could occur. The main origins of the background noise in the region where the signal could occur. The main origins of the background noise are found to be e+ - e- pairs induced by heavy energy gamma rays. These gamma rays follow the thermal neutron capture by the components of the detector. Another factor in the production of background noise is natural radio-activity. For example, the presence of Radon in the laboratory has been observed to produce deposits of 214Bi on the sides of the detector. Data taken with the NEMO 2 prototype and an enriched molybdenum source foil indicates that the background limit reached is of the order of 1 event per year in the 3 MeV region. Results of this work have proven the necessity to have a magnetic field in NEMO 3 in order to reject e+ - e-pairs. (author)

  13. Current IGEX Results for Neutrinoless Double-Beta Decay of 76Ge

    The International Germanium Experiment (IGEX) is currently operating three 2-kg enriched germanium detectors in the Canfranc Underground Laboratory (Spain) at 2450 mwe, in a search for the neutrinoless double-beta decay of 76Ge. The detectors are equipped with Pulse Shape Analysis electronics. This implementation of Pulse Shape Discrimination results in a rejection of 60%-80% of the background in the 2.0-2.5 MeV energy interval. Analysis of 116.75 mole-years of data yields a lower bound ≥ 1.57 x 1025y (or T0ν1/2 ≥ 1.13 x 1025y without PSD) (90% C.L.) corresponding to (mν) < (0.33 - 1.31) eV, depending on the theoretical nuclear matrix elements used to extract the neutrino mass parameter

  14. Exploration of Pixelated detectors for double beta decay searches within the COBRA experiment

    The aim of the COBRA experiment is the search for neutrinoless double beta decay events in Cadmium Zinc Telluride (CdZnTe) room temperature semiconductor detectors. The development of pixelated detectors provides the potential for clear event identification and thus major background reduction. The tracking option of a semiconductor is a unique approach in this field. For initial studies, several possible detector systems are considered with a special regard for low background applications: the large volume system Polaris with a pixelated CdZnTe sensor, Timepix detectors with Si and enriched CdTe sensor material and a CdZnTe pixel system developed at the Washington University in St. Louis, USA. For all detector systems first experimental background measurements taken at underground laboratories (Gran Sasso Underground Laboratory in Italy, LNGS and the Niederniveau Messlabor Felsenkeller in Dresden, Germany) and additionally for the Timepix detectors simulation results are presented.

  15. Depth Requirements for a Tonne-scale 76Ge Neutrinoless Double-beta Decay Experiment

    Aguayo, E; Back, H O; Barabash, A S; Bergevin, M; Bertrand, F E; Boswell, M; Brudanin, V; Busch, M; Chan, Y-D; Christofferson, C D; Collar, J I; Combs, D C; Cooper, R J; Detwiler, J A; Doe, P J; Efremenko, Yu; Egorov, V; Ejiri, H; Elliott, S R; Esterline, J; Fast, J E; Fields, N; Finnerty, P; Fraenkle, F M; Gehman, V M; Giovanetti, G K; Green, M P; Guiseppe, V E; Gusey, K; Hallin, A L; Hazama, R; Henning, R; Hime, A; Hoppe, E W; Horton, M; Howard, S; Howe, M A; Johnson, R A; Keeter, K J; Keillor, M E; Keller, C; Kephart, J D; Kidd, M F; Knecht, A; Kochetov, O; Konovalov, S I; Kouzes, R T; LaFerriere, B D; LaRoque, B H; Leon, J; Leviner, L E; Loach, J C; MacMullin, S; Marino, M G; Martin, R D; Mei, D -M; Merriman, J H; Miller, M L; Mizouni, L; Nomachi, M; Orrell, J L; Overman, N R; Phillips, D G; Poon, A W P; Perumpilly, G; Prior, G; Radford, D C; Rielage, K; Robertson, R G H; Ronquest, M C; Schubert, A G; Shima, T; Shirchenko, M; Snavely, K J; Sobolev, V; Steele, D; Strain, J; Thomas, K; Timkin, V; Tornow, W; Vanyushin, I; Varner, R L; Vetter, K; Vorren, K; Wilkerson, J F; Wolfe, B A; Yakushev, E; Young, A R; Yu, C -H; Yumatov, V; Zhang, C

    2011-01-01

    Neutrinoless double-beta decay experiments can potentially determine the Majorana or Dirac nature of the neutrino, and aid in understanding the neutrino absolute mass scale and hierarchy. Future 76Ge-based searches target a half-life sensitivity of >10^27 y to explore the inverted neutrino mass hierarchy. Reaching this sensitivity will require a background rate of ~5200 meters water equivalent is required for a tonne-scale experiment with a compact shield similar to the planned 40-kg MAJORANA DEMONSTRATOR. The required overburden is highly dependent on the chosen shielding configuration and could be relaxed significantly if, for example, a liquid cryogen and water shield, or an active neutron shield were employed. Operation of the MAJORANA DEMONSTRATOR and GERDA detectors will serve to reduce the uncertainties on cosmic-ray background rates and will impact the choice of shielding style and location for a future tonne-scale experiment.

  16. Monte Carlo evaluation of the muon-induced background in the GERDA double beta decay experiment

    The new generation of experiments searching for neutrinoless double beta decay is aiming at a background level of 10-3counts/(kgkeVy) or better at the respective Q-values. Cosmic ray muons can be a significant contribution due to a number of physics processes. The GERmanium Detector Array, GERDA, located at the Gran Sasso underground laboratory in Italy, uses germanium enriched in 76Ge as source and detector material. Germanium is submerged into liquid nitrogen or argon that acts as cooling medium and radiation shield simultaneously. A detailed Geant4-based Monte Carlo simulation was performed to calculate the photon and neutron fluxes induced by cosmic ray muons. The prompt background contributions from γ-ray and neutron interactions as well as the delayed contributions due to the production of radioactive isotopes within the setup are given. The background can be reduced to the desired level with the muon veto system incorporated in the GERDA design

  17. Status of the GERDA experiment aimed to search for neutrinoless double beta decay of 76Ge

    Smolnikov, Anatoly A

    2008-01-01

    The progress in the development of the new international Gerda (GErmanium Detector Array) experiment is presented. Main purpose of the experiment is to search for the neutrinoless double beta decay of 76Ge. The experimental set up is under construction in the underground laboratory of LNGS. Gerda will operate with bare germanium semiconductor detectors (enriched in 76Ge) situated in liquid argon. In the Phase I the existing enriched detectors from the previous Heidelberg-Moscow and IGEX experiments are employed, in the Phase II the new segmented detectors made from recently produced enriched material will be added. Novel concepts for background suppression including detector segmentation and anti-coincidence with LAr scintillation are developed.

  18. Phase II Upgrade of the GERDA Experiment for the Search of Neutrinoless Double Beta Decay

    Majorovits, B.

    Observation of neutrinoless double beta decay could answer the question regarding the Majorana or Dirac nature of neutrinos. The GERDA experiment utilizes HPGe detectors enriched with the isotope 76Ge to search for this process. Recently the GERDA collaboration has unblinded data of Phase I of the experiment. In order to further improve the sensitivity of the experiment, additionally to the coaxial detectors used, 30 BEGe detectors made from germanium enriched in 76Ge will be deployed in GERDA Phase II. BEGe detectors have superior PSD capability, thus the background can be further reduced. The liquid argon surrounding the detector array will be instrumented in order to reject background by detecting scintillation light induced in the liquid argon by radiation. After a short introduction the hardware preparations for GERDA Phase II as well as the processing and characterization of the 30 BEGe detectors are discussed.

  19. The MGDO software library for data analysis in Ge neutrinoless double-beta decay experiments

    Agostini, M; Finnerty, P; Kröninger, K; Lenz, D; Liu, J; Marino, M G; Martin, R; Nguyen, K D; Pandola, L; Schubert, A G; Volynets, O; Zavarise, P

    2011-01-01

    The GERDA and Majorana experiments will search for neutrinoless double-beta decay of germanium-76 using isotopically enriched high-purity germanium detectors. Although the experiments differ in conceptual design, they share many aspects in common, and in particular will employ similar data analysis techniques. The collaborations are jointly developing a C++ software library, MGDO, which contains a set of data objects and interfaces to encapsulate, store and manage physical quantities of interest, such as waveforms and high-purity germanium detector geometries. These data objects define a common format for persistent data, whether it is generated by Monte Carlo simulations or an experimental apparatus, to reduce code duplication and to ease the exchange of information between detector systems. MGDO also includes general-purpose analysis tools that can be used for the processing of measured or simulated digital signals. The MGDO design is based on the Object-Oriented programming paradigm and is very flexible, a...

  20. Research and Development Supporting a Next Generation Germanium Double Beta Decay Experiment

    Rielage, Keith; Elliott, Steve; Chu, Pinghan; Goett, Johnny; Massarczyk, Ralph; Xu, Wenqin

    2015-10-01

    To improve the search for neutrinoless double beta decay, the next-generation experiments will increase in source mass and continue to reduce backgrounds in the region of interest. A promising technology for the next generation experiment is large arrays of Germanium p-type point contact detectors enriched in 76-Ge. The experience, expertise and lessons learned from the MAJORANA DEMONSTRATOR and GERDA experiments naturally lead to a number of research and development activities that will be useful in guiding a future experiment utilizing Germanium. We will discuss some R&D activities including a hybrid cryostat design, background reduction in cabling, connectors and electronics, and modifications to reduce assembly time. We acknowledge the support of the U.S. Department of Energy through the LANL/LDRD Program.

  1. Results on neutrinoless double beta decay of 76Ge from the GERDA experiment

    Palioselitis, Dimitrios

    2015-05-01

    The Germanium Detector Array (GERDA) experiment is searching for neutrinoless double beta (0νββ) decay of 76Ge, a lepton number violating nuclear process predicted by extensions of the Standard Model. GERDA is an array of bare germanium diodes immersed in liquid argon located at the Gran Sasso National Laboratory (LNGS) in Italy. The results of the GERDA Phase I data taking with a total exposure of 21.6 kg yr and a background index of 0.01 cts/(keV kg yr) are presented in this paper. No signal was observed and a lower limit of T1/20ν > 2.1×1025 yr (90% C.L.) was derived for the half-life of the 0νββ decay of 76Ge. Phase II of the experiment aims to reduce the background around the region of interest by a factor of ten.

  2. Probing flavor models with Ge-76-based experiments on neutrinoless double-beta decay

    Agostini, Matteo; Zuber, Kai

    2015-01-01

    The physics impact of a staged approach for double-beta decay experiments based on Ge-76 is studied. The scenario considered relies on realistic time schedules envisioned by the GERDA and the MAJORANA collaborations, which are jointly working towards the realization of a future larger scale Ge-76 experiment. Intermediate stages of the experiments are conceived to perform quasi background-free measurements, and different data sets can be reliably combined to maximize the physics outcome. The sensitivity for such a global analysis is presented, with focus on how neutrino flavor models can be probed already with preliminary phases of the experiments. The synergy between theory and experiment yields strong benefits for both sides: the model predictions can be used to sensibly plan the experimental stages, and results from intermediate stages can be used to constrain whole groups of theoretical scenarios. This strategy clearly generates added value to the experimental efforts, while at the same time it allows to a...

  3. First Search for Lorentz and CPT Violation in Double Beta Decay with EXO-200

    Kaufman, L J

    2016-01-01

    This proceedings contribution reports the first experimental search for Lorentz- and CPT-violating signals specifically studying the effect of the Standard-Model Extension (SME) oscillation-free momentum-independent neutrino coupling operator in the double beta decay process. The search has been performed using an exposure of 100 kg yr of $^{136}$Xe with the EXO-200 detector. No significant evidence of the spectral modification due to isotropic Lorentz violation was found. A two-sided limit of $-2.65 \\times 10^{-5}$ GeV $<$ $\\mathring{a}_{\\mathrm{of}}^{(3)}$ $< 7.60 \\times 10^{-6}$ GeV (90% C.L.) is placed on the relevant coefficient within the SME.

  4. Neutrinoless double-beta decay in left-right symmetric models

    Neutrinoless double-beta decay is calculated via doubly charged Higgs, which occur naturally in left-right symmetric models. We find that the comparison with known half-lives yields values of phenomenological parameters which are compatible with earlier analyses of neutral current data. In particular, we obtain a right-handed gauge-boson mass lower bound of the order of 240 GeV. Using this result and expressions for neutrino masses derived in a parity non-conserving left-right symmetric model, we obtain msub(νsub(e)) < 1.5 eV, msub(νsub(μ)) < 0.05 MeV and msub(νsub(tau)) < 18 MeV

  5. Bounds for Neutrinoless Double Beta Decay in SO(10) Inspired Seesaw Models

    Buccella, F.; Falcone, D.

    By requiring the lower limit for the lightest right-handed neutrino mass, obtained in the baryogenesis from leptogenesis scenario, and a Dirac neutrino mass matrix similar to the up-quark mass matrix, we predict small values for the νe mass and for the matrix element mee responsible of the neutrinoless double beta decay, mνe around 5×10-3 eV and mee smaller than 10-3 eV, respectively. The allowed range for the mass of the heaviest right-handed neutrino is centered around the value of the scale of B-L breaking in the SO(10) gauge theory with Pati-Salam intermediate symmetry.

  6. Pions in nuclei and manifestations of supersymmetry in neutrinoless double beta decay

    We examine the pion realization of the short ranged supersymmetric (SUSY) mechanism of neutrinoless double beta decay (0νββ-decay). It originates from the R-parity violating quark-lepton interactions of the SUSY extensions of the standard model of the electroweak interactions. We argue that pions are dominant SUSY mediators in 0νββ-decay. The corresponding nuclear matrix elements for potentially 0νββ-decaying isotopes are calculated within the proton-neutron renormalized quasiparticle random phase approximation (pn-RQRPA). We define those isotopes which are most sensitive to the SUSY signal and outlook the present experimental situation with the 0νββ-decay searches for the SUSY. Upper limits on the R-parity violating 1st generation Yukawa coupling λ'111 are derived from various 0νββ - experiments

  7. Experiment TGV-2. Search for double beta decay of 106Cd

    Rukhadze, N. I.; Bakalyarov, A. M.; Briançon, Ch; Brudanin, V. B.; Čermák, P.; Egorov, V. G.; Klimenko, A. A.; Kovalik, A.; Lebedev, V. I.; Rukhadze, E. N.; Mamedov, F.; Shitov, Yu A.; Šimkovic, F.; Štekl, I.; Timkin, V. V.; Zhukov, S. V.

    2012-07-01

    The search for double beta decay of 106Cd was performed at the Modane underground laboratory (France, 4800 m.w.e.) using the multi-detector spectrometer TGV-2. 16 samples (~13.6 g) of 106Cd with an enrichment of 75% were installed between neighbouring HPGe detectors and measured during 12900 h. New half-life limits (at 90% CL) were obtained for 2νEC/EC decay of 106Cd to the ground state of 106Pd - T1/2 > 4.2 × 1020 y, and for OνEC/EC resonant decay of 106Cd to 2741 keV and 2718 keV excited states of 106Pd - T1/2 > 1.8 × 1020y and T1/2 > 1.6 × 1020y respectively.

  8. Experiment TGV-2. Search for double beta decay of 106Cd

    The search for double beta decay of 106Cd was performed at the Modane underground laboratory (France, 4800 m.w.e.) using the multi-detector spectrometer TGV-2. 16 samples (∼13.6 g) of 106Cd with an enrichment of 75% were installed between neighbouring HPGe detectors and measured during 12900 h. New half-life limits (at 90% CL) were obtained for 2νEC/EC decay of 106Cd to the ground state of 106Pd - T1/2 > 4.2 × 1020 y, and for OνEC/EC resonant decay of 106Cd to 2741 keV and 2718 keV excited states of 106Pd - T1/2 > 1.8 × 1020y and T1/2 > 1.6 × 1020y respectively.

  9. Radiopurity assessment of the tracking readout for the NEXT double beta decay experiment

    Álvarez, V; Barrado, A I; Bettini, A; Borges, F I G M; Camargo, M; Cárcel, S; Cebrián, S; Cervera, A; Conde, C A N; Conde, E; Dafni, T; Díaz, J; Esteve, R; Fernandes, L M P; Fernández, M; Ferrario, P; Ferreira, A L; Freitas, E D C; Gehman, V M; Goldschmidt, A; Gómez, H; Gómez-Cadenas, J J; González-Díaz, D; Gutiérrez, R M; Hauptman, J; Morata, J A Hernando; Herrera, D C; Iguaz, F J; Irastorza, I G; Labarga, L; Laing, A; Liubarsky, I; Lorca, D; Losada, M; Luzón, G; Marí, A; Martín-Albo, J; Martínez, A; Martínez-Lema, G; Miller, T; Monrabal, F; Monserrate, M; Monteiro, C M B; Mora, F J; Moutinho, L M; Vidal, J Muñoz; Nebot-Guinot, M; Nygren, D; Oliveira, C A B; de Solórzano, A Ortiz; Pérez, J; Aparicio, J L Pérez; Renner, J; Ripoll, L; Rodríguez, A; Rodríguez, J; Santos, F P; Santos, J M F dos; Segui, L; Serra, L; Shuman, D; Simón, A; Sofka, C; Sorel, M; Toledo, J F; Torrent, J; Tsamalaidze, Z; Veloso, J F C A; Villar, J A; Webb, R C; White, J T; Yahlali, N

    2014-01-01

    The 'Neutrino Experiment with a Xenon Time-Projection Chamber' (NEXT) is intended to investigate the neutrinoless double beta decay of 136Xe, which requires a severe suppression of potential backgrounds; therefore, an extensive screening and selection process is underway to control the radiopurity levels of the materials to be used in the experimental set-up of NEXT. The detector design combines the measurement of the topological signature of the event for background discrimination with the energy resolution optimization. Separate energy and tracking readout planes are based on different sensors: photomultiplier tubes for calorimetry and silicon multi-pixel photon counters for tracking. The design of a radiopure tracking plane, in direct contact with the gas detector medium, was a challenge since the needed components have typically activities too large for experiments requiring ultra-low background conditions. Here, the radiopurity assessment of tracking readout components based on gamma-ray spectroscopy usi...

  10. Radiopurity control in the NEXT-100 double beta decay experiment: procedures and initial measurements

    Alvarez, V; Bettini, A; Borges, F I G M; Carcel, S; Castel, J; Catala, J M; Cebrian, S; Cervera, A; Conde, C A N; Dafni, T; Dias, T H V T; Diaz, J; Egorov, M; Esteve, R; Evtoukhovitch, P; Fernandes, L M P; Ferrario, P; Ferreira, A L; Ferrer-Ribas, E; Freitas, E D C; Gehman, V M; Gil, A; Giomataris, I; Goldschmidt, A; Gomez, H; Gomez-Cadenas, J J; Gonzalez, K; Gonzalez-Diaz, D; Gutierrez, R M; Hauptman, J; Morata, J A Hernando; Herrera, D C; Herrero, V; Iguaz, F J; Irastorza, I G; Kalinnikov, V; Labarga, L; Liubarsky, I; Lopes, J A M; Lorca, D; Losada, M; Luzon, G; Mari, A; Martin-Albo, J; Martinez, A; Miller, T; Moiseenko, A; Monrabal, F; Monteiro, C M B; Monzo, J M; Mora, F J; Moutinho, L M; Vidal, J Munoz; da Luz, H Natal; Navarro, G; Nebot, M; Nygren, D; Oliveira, C A B; de Solorzano, A Ortiz; Palma, R; Perez, J; Aparicio, J L Perez; Renner, J; Ripoll, L; Rodriguez, A; Rodriguez, J; Santos, F P; Santos, J M F dos; Segui, L; Serra, L; Shuman, D; Simon, A; Sofka, C; Sorel, M; Toledo, J F; Tomas, A; Torrent, J; Tsamalaidze, Z; Vazquez, D; Velicheva, E; Veloso, J F C A; Villar, J A; Webb, R C; Weber, T; White, J; Yahlali, N

    2012-01-01

    The Neutrino Experiment with a Xenon TPC (NEXT) is intended to investigate the neutrinoless double beta decay of 136Xe, which requires a severe suppression of potential backgrounds. An extensive screening and material selection process is underway for NEXT since the control of the radiopurity levels of the materials to be used in the experimental set-up is a must for rare event searches. First measurements based on Glow Discharge Mass Spectrometry and gamma-ray spectroscopy using ultra-low background germanium detectors at the Laboratorio Subterr\\'aneo de Canfranc (Spain) are described here. Activity results for natural radioactive chains and other common radionuclides are summarized, being the values obtained for some materials like copper and stainless steel very competitive. The implications of these results for the NEXT experiment are also discussed.

  11. Neutrinoless double beta decay. Electron angular correlation as a probe of new physics

    The angular distribution of the final electrons in the so-called long range mechanism of the neutrinoless double beta decay (0ν2β) is derived for the general Lorentz invariant effective Lagrangian. Possible theories beyond the SM are classified from their effects on the angular distribution, which could be used to discriminate among various particle physics models inducing 0ν2β decays. However, additional input on the effective couplings will be required to single out the light Majorana-neutrino mechanism. Alternatively, measurements of the effective neutrino mass and angular distribution in 0ν2β decays can be used to put independent bounds on the parameters of the underlying physics models. This is illustrated for the mass of the right-handed WR boson of the left-right symmetric model for assumed values of the angular correlation coefficient and either the effective Majorana neutrino mass or the half-life of the decay. (Orig.)

  12. Lucifer:. AN Experimental Breakthrough in the Search for Neutrinoless Double Beta Decay

    Dafinei, I.; Ferroni, F.; Giuliani, A.; Pirro, S.; Previtali, E.

    2011-03-01

    LUCIFER (Low-background Underground Cryogenic Installation For Elusive Rates) is a new project for the study of neutrinoless Double Beta Decay, based on the technology of the scintillating bolometers. These devices promise a very efficient rejection of the a background, opening the way to a virtually background-free experiment if candidates with a transition energy higher than 2615 keV are investigated. The baseline candidate for LUCIFER is 82Se. This isotope will be embedded in ZnSe crystals grown with enriched selenium and operated as scintillating bolometers in a low-radioactivity underground dilution refrigerator. In this paper, the LUCIFER concept will be introduced and the sensitivity and the prospects related to this project will be discussed.

  13. The search for Majorana neutrinos with neutrinoless double beta decays: From CUORICINO to LUCIFER experiment

    Bellini, F.

    2012-11-01

    The study of neutrino properties is one of the fundamental challenges in particle physics nowadays. Fifty years of investigations established that neutrinos are massive but the absolute mass scale has not yet been measured. Moreover its true nature is still unknown. Is the neutrino its own antiparticle (thus violating the lepton number) as proposed by Majorana in 1937? The only way to probe the neutrino nature is through the observation of Neutrinoless Double Beta Decay (0νββ), a very rare spontaneous nuclear transition which emits two electrons and no neutrinos. In this paper, after a brief introduction to the theoretical framework of Majorana's neutrino, a presentation of experimental challenges posed by 0νββ search will be given as well as an overview of present status and future perpectives of experiments.

  14. LUCIFER, a potentially background-free approach to the search for neutrinoless double beta decay

    Nones, C. [Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse, Bat. 108 Orsay Campus - Orsay (France)

    2011-08-15

    LUCIFER (Low-background Underground Cryogenic Installation For Elusive Rates) is a new project for the study of neutrinoless Double Beta Decay, based on the technology of scintillating bolometers. These devices promise a very efficient rejection of the alpha background, opening the way to a virtual background-free experiment if candidates with a transition energy higher than 2615 keV are investigated. The baseline candidate for LUCIFER is {sup 82}Se. This isotope will be embedded in ZnSe crystals grown with enriched selenium and operated as scintillating bolometers in a low-radioactivity underground dilution refrigerator. In this paper, the LUCIFER concept will be introduced. The sensitivity and the very promising prospects related to this project will be discussed.

  15. LUCIFER, a potentially background-free approach to the search for neutrinoless double beta decay

    Nones, C.; Lucifer Group

    2011-08-01

    LUCIFER (Low-background Underground Cryogenic Installation For Elusive Rates) is a new project for the study of neutrinoless Double Beta Decay, based on the technology of scintillating bolometers. These devices promise a very efficient rejection of the alpha background, opening the way to a virtual background-free experiment if candidates with a transition energy higher than 2615 keV are investigated. The baseline candidate for LUCIFER is 82Se. This isotope will be embedded in ZnSe crystals grown with enriched selenium and operated as scintillating bolometers in a low-radioactivity underground dilution refrigerator. In this paper, the LUCIFER concept will be introduced. The sensitivity and the very promising prospects related to this project will be discussed.

  16. LUCIFER, a potentially background-free approach to the search for neutrinoless double beta decay

    LUCIFER (Low-background Underground Cryogenic Installation For Elusive Rates) is a new project for the study of neutrinoless Double Beta Decay, based on the technology of scintillating bolometers. These devices promise a very efficient rejection of the alpha background, opening the way to a virtual background-free experiment if candidates with a transition energy higher than 2615 keV are investigated. The baseline candidate for LUCIFER is 82Se. This isotope will be embedded in ZnSe crystals grown with enriched selenium and operated as scintillating bolometers in a low-radioactivity underground dilution refrigerator. In this paper, the LUCIFER concept will be introduced. The sensitivity and the very promising prospects related to this project will be discussed.

  17. The search for Majorana neutrinos with neutrinoless double beta decays: From CUORICINO to LUCIFER experiment

    The study of neutrino properties is one of the fundamental challenges in particle physics nowadays. Fifty years of investigations established that neutrinos are massive but the absolute mass scale has not yet been measured. Moreover its true nature is still unknown. Is the neutrino its own antiparticle (thus violating the lepton number) as proposed by Majorana in 1937? The only way to probe the neutrino nature is through the observation of Neutrinoless Double Beta Decay (0νββ), a very rare spontaneous nuclear transition which emits two electrons and no neutrinos. In this paper, after a brief introduction to the theoretical framework of Majorana's neutrino, a presentation of experimental challenges posed by 0νββ search will be given as well as an overview of present status and future perpectives of experiments.

  18. Neutrino nuclear responses for double beta decays and astro neutrinos by charge exchange reactions

    Ejiri, Hiroyasu

    2014-09-01

    Neutrino nuclear responses are crucial for neutrino studies in nuclei. Charge exchange reactions (CER) are shown to be used to study charged current neutrino nuclear responses associated with double beta decays(DBD)and astro neutrino interactions. CERs to be used are high energy-resolution (He3 ,t) reactions at RCNP, photonuclear reactions via IAR at NewSUBARU and muon capture reactions at MUSIC RCNP and MLF J-PARC. The Gamow Teller (GT) strengths studied by CERs reproduce the observed 2 neutrino DBD matrix elements. The GT and spin dipole (SD) matrix elements are found to be reduced much due to the nucleon spin isospin correlations and the non-nucleonic (delta isobar) nuclear medium effects. Impacts of the reductions on the DBD matrix elements and astro neutrino interactions are discussed.

  19. Upgrading KamLAND-Zen for improved sensitivity to neutrinoless double-beta decay

    Krupczak, Emmett; KamLAND-Zen Collaboration

    2015-10-01

    KamLAND is a 1 kton liquid scintillator antineutrino detector located underground in Kamioka, Japan. The KamLAND-Zen experiment began in 2011, using KamLAND to search for neutrinoless double-beta decay (0 νββ). This process, if observed, would indicate that neutrinos are their own antiparticle and thus are Majorana fermions, a discovery that could help explain the matter-antimatter discrepancy in our universe. Currently, KamLAND-Zen is one of the most sensitive experiments to 0 νββ . In order to improve upon the present limits for 0 νββ , KamLAND is undergoing a series of upgrades to reduce background. This includes the construction of a new inner nylon chamber (``mini-balloon''). The current results and design considerations for the mini-balloon will be discussed.

  20. ZICOS - New project for neutrinoless double beta decay experiment using zirconium complex in liquid scintillator

    Fukuda, Yoshiyuki

    2016-05-01

    A liquid scintillator containing a tetrakis (isopropyl acetoacetato) zirconium has been developed for new project of neutrinoless double beta decay experiment (ZICOS experiment). We have synthesized a tetrakis (isopropyl acetoacetato) zirconium, which have high solubility (over 31.2 wt.%) in anisole. We measured the performance of liquid scintillator containing 10 wt.% concentration of a tetrakis (isopropyl acetoacetato) zirconium, and obtained 48.7 ± 7.1% of the light yield of BC505 and the energy resolution of 4.1 ± 0.6% at 3.35 MeV assuming 40% photo coverage of the photomultiplier, respectively. We also estimated that ZICOS experiment should be sensitive to (mν) Zen using Cherenkov lights.

  1. Neutrinoless Double Beta Decay in LRSM with Natural Type-II seesaw Dominance

    Pritimita, Prativa; Patra, Sudhanwa

    2016-01-01

    We present a detailed discussion on neutrinoless double beta decay within a class of left-right symmetric models where neutrino mass originates by natural type II seesaw dominance. The spontaneous symmetry breaking is implemented with doublets, triplets and bidoublet scalars. The fermion sector is extended with an extra sterile neutrino per generation that helps in implementing the seesaw mechanism. The presence of extra particles in the model exactly cancels type-I seesaw and allows large value for Dirac neutrino mass matrix $M_D$. The key feature of this work is that all the physical masses and mixing are expressed in terms of neutrino oscillation parameters and lightest neutrino mass thereby facilitating to constrain light neutrino masses from $0\

  2. Exploring the Neutrinoless Double Beta Decay in the Inverted Neutrino Hierarchy with Bolometric Detectors

    Artusa, D R; Azzolini, O; Balata, M; Banks, T I; Bari, G; Beeman, J; Bellini, F; Bersani, A; Biassoni, M; Brofferio, C; Bucci, C; Cai, X Z; Camacho, A; Canonica, L; Cao, X G; Capelli, S; Carbone, L; Cardani, L; Carrettoni, M; Casali, N; Chiesa, D; Chott, N; Clemenza, M; Cosmelli, C; Cremonesi, O; Creswick, R J; Dafinei, I; Dally, A; Datskov, V; De Biasi, A; Deninno, M M; Di Domizio, S; di Vacri, M L; Ejzak, L; Fang, D Q; Farach, H A; Faverzani, M; Fernandes, G; Ferri, E; Ferroni, F; Fiorini, E; Franceschi, M A; Freedman, S J; Fujikawa, B K; Giachero, A; Gironi, L; Giuliani, A; Goett, J; Gorla, P; Gotti, C; Gutierrez, T D; Haller, E E; Han, K; Heeger, K M; Hennings-Yeomans, R; Huang, H Z; Kadel, R; Kazkaz, K; Keppel, G; Kolomensky, Yu G; Li, Y L; Ligi, C; Liu, X; Ma, Y G; Maiano, C; Maino, M; Martinez, M; Maruyama, R H; Mei, Y; Moggi, N; Morganti, S; Napolitano, T; Nisi, S; Nones, C; Norman, E B; Nucciotti, A; O'Donnell, T; Orio, F; Orlandi, D; Ouellet, J L; Pallavicini, M; Palmieri, V; Pattavina, L; Pavan, M; Pedretti, M; Pessina, G; Pettinacci, V; Piperno, G; Pira, C; Pirro, S; Previtali, E; Rampazzo, V; Rosenfeld, C; Rusconi, C; Sala, E; Sangiorgio, S; Scielzo, N D; Sisti, M; Smith, A R; Taffarello, L; Tenconi, M; Terranova, F; Tian, W D; Tomei, C; Trentalange, S; Ventura, G; Vignati, M; Wang, B S; Wang, H W; Wielgus, L; Wilson, J; Winslow, L A; Wise, T; Woodcraft, A; Zanotti, L; Zarra, C; Zhu, B X; Zucchelli, S

    2014-01-01

    Neutrinoless double beta decay (0nubb) is one of the most sensitive probes for physics beyond the Standard Model, providing unique information on the nature of neutrinos. In this paper we review the status and outlook for bolometric 0nubb decay searches. We summarize recent advances in background suppression demonstrated using bolometers with simultaneous readout of heat and light signals. We simulate several configurations of a future CUORE-like bolometer array which would utilize these improvements and present the sensitivity reach of a hypothetical next-generation bolometric 0nubb experiment. We demonstrate that a bolometric experiment with the isotope mass of about 1 ton is capable of reaching the sensitivity to the effective Majorana neutrino mass (|mee|) of order 10-20 meV, thus completely exploring the so-called inverted neutrino mass hierarchy region. We highlight the main challenges and identify priorities for an R&D program addressing them.

  3. Shell-model calculation of neutrinoless double-$\\beta$ decay of $^{76}$Ge

    Sen'kov, R A

    2015-01-01

    In this article we present a more detailed version of our recent Rapid Communication [Phys. Rev. C 90, 051301(R) (2014)] where we calculate the nuclear matrix elements for neutrinoless double-$\\beta$ decay of $^{76}$Ge. For the calculations we use a novel method that has perfect convergence properties and allows one to obtain the nonclosure nuclear matrix elements for $^{76}$Ge with a 1% accuracy. We present a new way of calculation of the optimal closure energy, using this energy with the closure approximation provides the most accurate closure nuclear matrix elements. In addition, we present a new analysis of the heavy-neutrino-exchange nuclear matrix elements, and we compare occupation probabilities and Gamow-Teller strength with experimental data.

  4. Nuclear matrix elements in neutrinoless double beta decay: beyond mean-field covariant density functional theory

    Yao, J M; Hagino, K; Ring, P; Meng, J

    2014-01-01

    We report a systematic study of nuclear matrix elements (NMEs) in neutrinoless double-beta decays with state-of-the-art beyond mean-field covariant density functional theory. The dynamic effects of particle-number and angular-momentum conservations as well as quadrupole shape fluctuations are taken into account with projections and generator coordinate method for both initial and final nuclei. The full relativistic transition operator is adopted to calculate the NMEs which are found to be consistent with the results of previous beyond non-relativistic mean-field calculation based on a Gogny force with the exception of $^{150}$Nd. Our study shows that the total NMEs can be well approximated by the pure axial-vector coupling term, the calculation of which is computationally much cheaper than that of full terms.

  5. First array of enriched Zn$^{82}$Se bolometers to search for double beta decay

    Artusa, D R; Beeman, J W; Bellini, F; Biassoni, M; Brofferio, C; Camacho, A; Capelli, S; Cardani, L; Carniti, P; Casali, N; Cassina, L; Clemenza, M; Cremonesi, O; Cruciani, A; D'Addabbo, A; Dafinei, I; Di Domizio, S; di Vacri, M L; Ferroni, F; Gironi, L; Giuliani, A; Gotti, C; Keppel, G; Maino, M; Mancuso, M; Martinez, M; Morganti, S; Nagorny, S; Nastasi, M; Nisi, S; Nones, C; Orio, F; Orlandi, D; Pagnanini, L; Pallavicini, M; Palmieri, V; Pattavina, L; Pavan, M; Pessina, G; Pettinacci, V; Pirro, S; Pozzi, S; Previtali, E; Puiu, A; Rusconi, C; Schaeffner, K; Tomei, C; Vignati, M; Zolotarova, A

    2016-01-01

    The R&D activity performed during the last years proved the potential of ZnSe scintillating bolometers to the search for neutrino-less double beta decay, motivating the realization of the first large-mass experiment based on this technology: CUPID-0. The isotopic enrichment in $^{82}$Se, the Zn$^{82}$Se crystals growth, as well as the light detectors production have been accomplished, and the experiment is now in construction at Laboratori Nazionali del Gran Sasso (Italy). In this paper we present the results obtained testing the first three Zn$^{82}$Se crystals operated as scintillating bolometers, and we prove that their performance in terms of energy resolution, background rejection capability and intrinsic radio-purity complies with the requirements of CUPID-0.

  6. Radon and material radiopurity assessment for the NEXT double beta decay experiment

    Cebrián, S; Bandac, I; Labarga, L; Álvarez, V; Barrado, A I; Bettini, A; Borges, F I G M; Camargo, M; Cárcel, S; Cervera, A; Conde, C A N; Conde, E; Dafni, T; Díaz, J; Esteve, R; Fernandes, L M P; Fernández, M; Ferrario, P; Freitas, E D C; Gehman, V M; Goldschmidt, A; Gómez-Cadenas, J J; González-Díaz, D; Gutiérrez, R M; Hauptman, J; Morata, J A Hernando; Herrera, D C; Irastorza, I G; Laing, A; Liubarsky, I; López-March, N; Lorca, D; Losada, M; Luzón, G; Marí, A; Martín-Albo, J; Martínez, A; Martínez-Lema, G; Miller, T; Monrabal, F; Monserrate, M; Monteiro, C M B; Mora, F J; Moutinho, L M; Vidal, J Muñoz; Nebot-Guinot, M; Nygren, D; Oliveira, C A B; de Solórzano, A Ortiz; Aparicio, J L Pérez; Querol, M; Renner, J; Ripoll, L; Rodríguez, J; Santos, F P; Santos, J M F dos; Serra, L; Shuman, D; Simón, A; Sofka, C; Sorel, M; Toledo, J F; Torrent, J; Tsamalaidze, Z; Veloso, J F C A; Villar, J A; Webb, R C; White, J T; Yahlali, N

    2015-01-01

    The Neutrino Experiment with a Xenon TPC (NEXT), intended to investigate the neutrinoless double beta decay using a high-pressure xenon gas TPC filled with Xe enriched in 136Xe at the Canfranc Underground Laboratory in Spain, requires ultra-low background conditions demanding an exhaustive control of material radiopurity and environmental radon levels. An extensive material screening process is underway for several years based mainly on gamma-ray spectroscopy using ultra-low background germanium detectors in Canfranc but also on mass spectrometry techniques like GDMS and ICPMS. Components from shielding, pressure vessel, electroluminescence and high voltage elements and energy and tracking readout planes have been analyzed, helping in the final design of the experiment and in the construction of the background model. The latest measurements carried out will be presented and the implication on NEXT of their results will be discussed. The commissioning of the NEW detector, as a first step towards NEXT, has star...

  7. First array of enriched Zn^{82}Se bolometers to search for double beta decay

    Artusa, D. R.; Balzoni, A.; Beeman, J. W.; Bellini, F.; Biassoni, M.; Brofferio, C.; Camacho, A.; Capelli, S.; Cardani, L.; Carniti, P.; Casali, N.; Cassina, L.; Clemenza, M.; Cremonesi, O.; Cruciani, A.; D'Addabbo, A.; Dafinei, I.; Di Domizio, S.; di Vacri, M. L.; Ferroni, F.; Gironi, L.; Giuliani, A.; Gotti, C.; Keppel, G.; Maino, M.; Mancuso, M.; Martinez, M.; Morganti, S.; Nagorny, S.; Nastasi, M.; Nisi, S.; Nones, C.; Orio, F.; Orlandi, D.; Pagnanini, L.; Pallavicini, M.; Palmieri, V.; Pattavina, L.; Pavan, M.; Pessina, G.; Pettinacci, V.; Pirro, S.; Pozzi, S.; Previtali, E.; Puiu, A.; Rusconi, C.; Schäffner, K.; Tomei, C.; Vignati, M.; Zolotarova, A.

    2016-07-01

    The R&D activity performed during the last years proved the potential of ZnSe scintillating bolometers to the search for neutrino-less double beta decay, motivating the realization of the first large-mass experiment based on this technology: CUPID-0. The isotopic enrichment in ^{82}Se, the Zn^{82}Se crystals growth, as well as the light detectors production have been accomplished, and the experiment is now in construction at Laboratori Nazionali del Gran Sasso (Italy). In this paper we present the results obtained testing the first three Zn^{82}Se crystals operated as scintillating bolometers, and we prove that their performance in terms of energy resolution, background rejection capability and intrinsic radio-purity complies with the requirements of CUPID-0.

  8. Exploration of Pixelated detectors for double beta decay searches within the COBRA experiment

    Schwenke, M., E-mail: schwenke@asp.tu-dresden.de [Institut fuer Kern- und Teilchenphysik, Technische Universitaet Dresden, Zellescher Weg 19, 01069 Dresden (Germany); Zuber, K.; Janutta, B. [Institut fuer Kern- und Teilchenphysik, Technische Universitaet Dresden, Zellescher Weg 19, 01069 Dresden (Germany); He, Z.; Zeng, F. [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, Michigan 48109-2104 (United States); Anton, G.; Michel, T.; Durst, J.; Lueck, F.; Gleixner, T. [Erlangen Centre for Astroparticle Physics, Friedrich-Alexander-Universitaet Erlangen-Nuernberg, Erwin-Rommel-Str. 1, 91058 Erlangen (Germany); Goessling, C.; Schulz, O.; Koettig, T. [Technische Universitaet Dortmund, Physik E IV, 44221 Dortmund (Germany); Krawczynski, H.; Martin, J. [Department of Physics, Washington University in St. Louis, Campus Box 1105, One Brookings Drive, St. Louis, MO 63130-4899 (United States); Stekl, I.; Cermak, P. [Institute of Experimental and Applied Physics, Czech Technical University in Prague, Horska 3a/22, 128 00 Prague (Czech Republic)

    2011-09-11

    The aim of the COBRA experiment is the search for neutrinoless double beta decay events in Cadmium Zinc Telluride (CdZnTe) room temperature semiconductor detectors. The development of pixelated detectors provides the potential for clear event identification and thus major background reduction. The tracking option of a semiconductor is a unique approach in this field. For initial studies, several possible detector systems are considered with a special regard for low background applications: the large volume system Polaris with a pixelated CdZnTe sensor, Timepix detectors with Si and enriched CdTe sensor material and a CdZnTe pixel system developed at the Washington University in St. Louis, USA. For all detector systems first experimental background measurements taken at underground laboratories (Gran Sasso Underground Laboratory in Italy, LNGS and the Niederniveau Messlabor Felsenkeller in Dresden, Germany) and additionally for the Timepix detectors simulation results are presented.

  9. Future perspectives of double beta decay and dark matter search - GENIUS

    The recent results from the HEIDELBERG-MOSCOW experiment have demonstrated the large potential of double beta decay to search for new physics beyond the standard model. To increase by a major step the present sensitivity for double beta decay and dark matter search, much bigger source strengths and much lower backgrounds are needed than used in experiments under operation at present or under construction. We describe here a project which would operate one tonne of 'naked' enriched germanium-detectors in liquid nitrogen as shielding in an underground set-up (GENIUS). It improves the sensitivity of neutrino masses to 0.01 eV. A 10 tonne version would probe neutrino masses even down to 10-3 eV. The first version would allow us to test the atmospheric neutrino problem, the second at least part of the solar neutrino problem. Both versions would allow, in addition, significant contributions to testing several classes of GUT models. These are especially tests of R-parity breaking and conserving supersymmetry models - including sneutrino masses - leptoquark masses and mechanism and right-handed W-boson masses comparable with LHC. The second issue of the experiment is the search for dark matter in the universe. The full MSSM parameter space for the prediction of neutralinos as dark matter particles could be covered already in a first step of the full experiment using only 100 kg of 76Ge or even of natural Ge making the experiment competitive with LHC in the search for supersymmetry. (author)

  10. Radiopure ZnMoO{sub 4} scintillating bolometers for the LUMINEU double-beta experiment

    Poda, D. V.; Chernyak, D. M. [CSNSM, Centre de Sciences Nucléaires et de Sciences de la Matière, CNRS/IN2P3, Université Paris-Sud, 91405 Orsay (France); Institute for Nuclear Research, MSP 03680 Kyiv (Ukraine); Armengaud, E.; Boissière, T. de; Fourches, N.; Gerbier, G.; Gros, M.; Hervé, S.; Magnier, P.; Navick, X-F.; Nones, C.; Paul, B.; Penichot, Y. [CEA, Centre d’Etudes Saclay, IRFU, 91191 Gif-Sur-Yvette Cedex (France); Arnaud, Q.; Augier, C.; Benoît, A.; Cazes, A.; Censier, B.; Charlieux, F.; De Jesus, M. [IPNL, Université de Lyon, Université Lyon 1, CNRS/IN2P3, 69622 Villeurbanne Cedex (France); and others

    2015-08-17

    The results of R&D of radiopure zinc molybdate (ZnMoO{sub 4}) based scintillating bolometers for the LUMINEU (Luminescent Underground Molybdenum Investigation for NEUtrino mass and nature) double-beta decay experiment are presented. A dedicated two-stage molybdenum purification technique (sublimation in vacuum and recrystallization from aqueous solutions) and an advanced directional solidification method (the low-thermal-gradient Czochralski technique) were utilized to produce high optical quality large mass (∼1 kg) ZnMoO{sub 4} crystal boules and first {sup 100}Mo (99.5%) enriched Zn{sup 100}MoO{sub 4} crystal scintillator (mass of ∼0.2 kg). Scintillating bolometers based on ZnMoO{sub 4} (≈ 0.33 kg) and Zn{sup 100}MoO{sub 4} (≈ 0.06 kg) scintillation elements and high purity Ge wafers were tested in the EDELWEISS set-up at the Modane Underground Laboratory (France). Long term low temperature tests demonstrate excellent detectors’ performance and effectiveness of the purification and solidification procedures for the achievement of high radiopurity of the material, in particular with a bulk activity of {sup 228}Th and {sup 226}Ra below 4 µBq/kg. The adopted protocol was used to produce for the first time a large volume Zn{sup 100}MoO{sub 4} crystal scintillator (mass of ∼1.4 kg, {sup 100}Mo enrichment is 99.5%) to search for neutrinoless double-beta decay of {sup 100}Mo in the framework of the LUMINEU project.

  11. Double beta decay - physics beyond the Standard Model now, and in future (GENIUS)

    Nuclear double beta decay provides an extraordinarily broad potential to search for beyond Standard Model physics, probing already now the TeV scale, on which new physics should manifest itself. These possibilities are reviewed here. First, the results of present generation experiments are presented. The most sensitive one of them-Heidelberg-Moscow experiment in the Gran Sasso - probes the electron mass now in the sub eV region and will reach a limit of ∼0.1 eV in a few years. Basing to a large extent on the theoretical work of the Heidelberg Double Beta Group in the last two years, results are obtained also for SUSY models (R-parity breaking, sneutrino mass), leptoquarks (leptoquark-Higgs coupling), compositeness, right-handed W boson mass and others. These results are comfortably competitive to corresponding results from high-energy accelerators like TEVATRON, HERA, etc. Second, future perspectives of ββ research are discussed. A new Heidelberg experimental proposal (GENIUS) is presented which would allow to increase the sensitivity for Majorana neutrino masses from the present level of at best 0.1 eV down to 0.01 or even 0.001 eV. Its physical potential would be a breakthrough into the multi-TeV range for many beyond standard models. Its sensitivity for neutrino oscillation parameters would be larger than of all present terrestrial neutrino oscillation experiments and of those planned for the future. It would further, already in a first step, cover almost the full MSSM parameter space for prediction of neutralinos as cold dark matter, making the experiment competitive to LHC in the search for supersymmetry. (author)

  12. Characterization of a ZnSe scintillating bolometer prototype for neutrinoless double beta decay search

    Tenconi, M.; Giuliani, A.; Nones, C.; Pessina, G.; Plantevin, O.; Rusconi, C.

    2014-01-01

    As proposed in the LUCIFER project, ZnSe crystals are attractive materials to realize scintillating bolometers aiming at the search for neutrinoless double beta decay of the promising isotope 82Se. However, the optimization of the ZnSe-based detectors is rather complex and requires a wide-range investigation of the crystal features: optical properties, crystalline quality, scintillation yields and bolometric behaviour. Samples tested up to now show problems in the reproducibility of crucial aspects of the detector performance. In this work, we present the results obtained with a scintillating bolometer operated aboveground at about 25 mK. The detector energy absorber was a single 1 cm3 ZnSe crystal. The good energy resolution of the heat channel (about 14 keV at 1460 keV) and the excellent alpha/beta discrimination capability are very encouraging for a successful realization of the LUCIFER program. The bolometric measurements were completed by optical tests on the crystal (optical transmission and luminescence measurements down to 10 K) and investigation of the crystalline structure. The work here described provides a set of parameters and procedures useful for a complete pre-characterization of ZnSe crystals in view of the realization of highly performing scintillating bolometers.

  13. LUCIFER: Scintillating bolometers for the search of Neutrinoless Double Beta Decay

    Vignati, M. [Sapienza Universita di Roma and INFN Sezione di Roma, Roma, I-00185 (Italy)

    2012-08-15

    The nature of neutrino mass is one of the frontier problems of particle physics. Neutrinoless Double Beta Decay (0{nu}DBD) is a powerful tool to measure the neutrino mass and to test possible extensions of the Standard Model. Bolometers are excellent detectors to search for this rare decay, thanks to their good energy resolution and to the low background conditions in which they can operate. The current challenge consists in the reduction of the background, represented by environmental {gamma}'s and {alpha}'s, in view of a zero background experiment. We present the LUCIFER R and D, funded by an European grant, in which the background can be reduced by an order of magnitude with respect to the present generation experiments. The technique is based on the simultaneous bolometric measurement of the heat and of the scintillation light produced by a particle, that allows to discriminate between {beta} and {alpha} particles. The {gamma} background is reduced by choosing 0{nu}DBD candidate isotopes with transition energy above the environmental {gamma}'s spectrum. The prospect of this R and D are discussed.

  14. Neutrino mass bounds from neutrinoless double beta-decays and cosmological probes

    Yong-Yeon Keum

    2016-02-01

    We investigate the way the total mass sum of neutrinos can be constrained from the neutrinoless double beta-decay and cosmological probes with cosmic microwave background (CMBR), large-scale structures including 2dFGRS and SDSS datasets. First we discuss, in brief, the current status of neutrino mass bounds from neutrino beta decays and cosmic constraint within the flat CMD model. In addition, we explore the interacting neutrino dark-energy model, where the evolution of neutrino masses is determined by quintessence scalar field, which is responsible for cosmic acceleration. Assuming the flatness of the Universe, the constraint we can derive from the current observation is < 0.87 eV at 95% confidence level, which is consistent with < 0.68 eV in the flat CDM model without Lyman alpha forest data. In the presence of Lyman- forest data, interacting dark-energy models prefer a weaker bound < 0.43 eV to < 0.17 eV (Seljark et al). Finally, we discuss the future prospect of the neutrino mass bound with weak-lensing effects.

  15. Constraining Majorana CP phase in the precision era of cosmology and the double beta decay experiment

    We show that precision measurement of (1) the sum of neutrino masses by cosmological observation and (2) the lifetime of neutrinoless double beta decay in ton-scale experiments, with supplementary use of (3) effective mass measured in a single beta decay experiment, would allow us to obtain information on the Majorana phase of neutrinos. To quantify the sensitivity to the phase, we use the CP exclusion fraction, a fraction of the CP phase parameter space that can be excluded for a given set of assumed input parameters, a global measure for CP violation. We illustrate the sensitivity under varying assumptions, from modest to optimistic ones, on experimental errors and theoretical uncertainty of nuclear matrix elements. Assuming that the latter can be reduced to a factor of ≃1.5, we find that one of the two Majorana phases (denoted as α21) can be constrained by excluding ≃10–40% of the phase space at the 2σ confidence level even with a modest choice of experimental error for the lowest neutrino mass of 0.1 eV. The characteristic features of the sensitivity to α21, such as dependences on the true values of α21, are addressed

  16. Characterization of a ZnSe scintillating bolometer prototype for neutrinoless double beta decay search

    Tenconi M.

    2014-01-01

    Full Text Available As proposed in the LUCIFER project, ZnSe crystals are attractive materials to realize scintillating bolometers aiming at the search for neutrinoless double beta decay of the promising isotope 82Se. However, the optimization of the ZnSe-based detectors is rather complex and requires a wide-range investigation of the crystal features: optical properties, crystalline quality, scintillation yields and bolometric behaviour. Samples tested up to now show problems in the reproducibility of crucial aspects of the detector performance. In this work, we present the results obtained with a scintillating bolometer operated aboveground at about 25 mK. The detector energy absorber was a single 1 cm3 ZnSe crystal. The good energy resolution of the heat channel (about 14 keV at 1460 keV and the excellent alpha/beta discrimination capability are very encouraging for a successful realization of the LUCIFER program. The bolometric measurements were completed by optical tests on the crystal (optical transmission and luminescence measurements down to 10 K and investigation of the crystalline structure. The work here described provides a set of parameters and procedures useful for a complete pre-characterization of ZnSe crystals in view of the realization of highly performing scintillating bolometers.

  17. delta beta-Thalassaemia in Sicily: report of a case of double heterozygosity for A gamma delta beta-thalassaemia and A gamma G gamma delta beta-thalassaemia.

    Musumeci,S; Romeo, M A; Pizzarelli, G.; Schilirò, G; Russo, G.

    1983-01-01

    A case of double heterozygosity for A gamma delta beta-thalassaemia and A gamma G gamma delta beta-thalassaemia was found during a screening programme in Sicily. The proband, a 4-year-old girl, showed a clinical picture of thalassaemia intermedia. Hb F (85.12% by the Singer method) was G gamma A gamma type. The parents and the brother were delta beta-thalassaemia carriers. Structural analysis of Hb F showed both G gamma and A gamma chains in the father, but only A gamma chains in the mother.

  18. Pattern recognition techniques to reduce backgrounds in the search for the 136Xe double beta decay with gaseous TPCs

    Iguaz, F J; Dafni, T; Gomez, H; Herrera, D C; Irastorza, I G; Luzon, G; Segui, L; Tomas, A

    2013-01-01

    The observation of the neutrinoless double beta decay may provide essential information on the nature of neutrinos. Among the current experimental approaches, a high pressure gaseous TPC is an attractive option for the search of double beta decay due to its good energy resolution and the detailed topological information of each event. We present in this talk a detailed study of the ionization topology of the 136Xe double beta decay events in a High Pressure Xenon TPC, as well as that of the typical competing backgrounds. We define some observables based on graph theory concepts to develop automated discrimination algorithms. Our criteria are able to reduce the background level by about three orders of magnitude in the region of interest of the 136Xe Qbb for a signal acceptance of 40%. This result provides a quantitative assessment of the benefit of topological information offered by gaseous TPCs for double beta decay search, and proves that it is a promising feature in view of future experiments in the field....

  19. Nuclear transparency and double beta decay of molybdenum 100. Annual report, February 1, 1995 - January 31, 1996

    This report describes progress in data analysis for a search for neutrinoless double-beta decay of molybdenum 100 and related work, Brookhaven National Laboratory's Experiment 850 on color transparency, and work on Brookhaven's EVA detector and the Stanford Linear Accelerator Center's B factory experiment. 6 refs

  20. Determination of neutrino mass ordering in future $^{76}$Ge-based neutrinoless double-beta decay experiments

    Zhang, Jue

    2016-01-01

    Motivated by recent intensive experimental efforts on searching for neutrinoless double-beta decays, we perform a detailed analysis of the physics potential of the experiments based on $^{76}{\\rm Ge}$. Assuming no signals, current and future experiments could place a $90\\%$ lower limit on the half life $T^{0\

  1. Double Beta Decay in Xenon-136. Measuring the Neutrino-Emitting Mode and Searching for Majoron-Emitting Modes

    Herrin, Steven [Stanford Univ., CA (United States)

    2013-06-01

    Observations of neutrino flavor oscillations have demonstrated that neutrinos have mass. Since the discovery of these oscillations, much progress has been made at mea- suring the neutrino mass-squared differences and lepton mixing angles that character- ize them. However, the origin and absolute scale of neutrino masses remain unknown. Unique among fermions, neutrinos can be Majorana particles, which could provide an explanation for neutrino masses. Discovery of a hypothetical process known as neutrinoless double beta decay would show that neutrinos are Majorana particles and determine the mass scale for neutrinos. The Enriched Xenon Observatory (EXO) is a series of experiments searching for the neutrinoless double beta decay of 136Xe. The first experiment, EXO-200, began operation in 2011 and makes use of 200 kg of xenon enriched to 80.6% in 136Xe. The analysis presented here makes use of data from EXO-200 to obtain a more precise measurement of the half-life for the two-neutrino-emitting mode of double beta decay than previously reported. The analysis also sets limits on the half-lives for exotic, Majoron-emitting modes of neutrinoless double beta decay. Data from EXO-200 is also used to produce a measurement of the cosmic muon flux at the WIPP under- ground site where EXO-200 is located.

  2. Direct mass measurements of cadmium and palladium isotopes and their double-beta transition Q-values

    Smorra, C.; Beyer, T.; Blaum, K.; Block, M.; Düllmann, Ch.E.(Institute of Nuclear Chemistry, Johannes Gutenberg University Mainz, Mainz, 55128, Germany); Eberhardt, K.; Eibach, M.; Eliseev, S.; Nagy, Sz.; Nörtershäuser, W; Renisch, D.

    2012-01-01

    The Q-value of the double-electron capture in Cd-108 has been determined to be (272.04 +/- 0.55) keV in a direct measurement with the double-Penning trap mass spectrometer TRIGA-TRAP. Based on this result a resonant enhancement of the decay rate of Cd-108 is excluded. We have confirmed the double-beta transition Q-values of Cd-106 and Pd-110 recently measured with the Penning-trap mass spectrometers SHIPTRAP and ISOLTRAP, respectively. Furthermore, the atomic masses of the involved nuclides C...

  3. Double beta decay searches of 134Xe, 126Xe and 124Xe with large scale Xe detectors

    The sensitivity for double beta decay studies of 134Xe and 124Xe is investigated assuming a potential large scale Xe experiment developed for dark matter searches depleted in 136Xe. The opportunity for an observation of the 2νββ - decay of 134Xe is explored for various scenarios. A positive observation should be possible for all calculated nuclear matrix elements. The detection of 2ν ECEC of 124Xe can be probed in all scenarios covering the theoretical predicted half-life uncertainties and a potential search for 126Xe is discussed. The sensitivity to β+EC decay of 124Xe is discussed and a positive observation might be possible, while β+β+ decay still remains unobservable. The performed studies take into account solar pp–neutrino interactions, 85Kr beta decay and remaining 136Xe double beta decay as background components in the depleted detector. (paper)

  4. Double beta decay of molybdenum 100: Annual progress report for period January 1, 1987-December 31, 1987

    Work is continuing on a collaborative experiment with experimenters from the Lawrence Berkeley Laboratory to search for neutrinoless and two neutrino double beta decays in 100Mo. Backgrounds in a detector stack consisting of 40 lithium-drifted, surface-barrier silicon detectors within a titanium cryostat shielded by 10 inches of lead, 2-4 inches of borated polyethylene, and 2 feet of wax 4000 feet underground have been studied with no 100Mo foils inserted, and, under these conditions, no background events simulating double beta decay candidates have survived cuts in an energy region extending from 2.55 to 3.5 MeV in approximately 1600 hours of running. In addition, using 20 100Mo foils from a second batch of 100Mo obtained from Oak Ridge comprising a total of approximately 1/6 mole (1.04 x 1023 atoms) of 100Mo, we have very recently obtained in only 400 hours of running a very preliminary one sigma lower limit on the lifetime estimate for zero neutrino double beta decay, based on one count, of greater than 2 x 1021 years (approximately 2 x 1022 years Ge equivalent) and an equally preliminary one sigma lower limit on the lifetime estimate for two neutrino double beta decay, based on excess counts in the 100Mo spectrum over the empty detector spectrum, of greater than 2 x 1019 years (approximately 1.5 x 1021 years Ge equivalent). In 400 hours, we have no candidates for majoron double beta decay. 2 figs

  5. Double beta decay experiments analyzed by the Faculty of Nuclear Science and Physical Engineering, Czech Technical University

    TGV and NEMO, two international collaboration projects are described. The TGV project deals with the double beta decay of 48Ca. In 1998, this project was augmented with the examination of the double beta decay of 106Cd - the β+β+, β+/EC, and EC/EC modes. The main objective of this experiment consists in recording the 2νEC/EC mode (0+ → 0+, ground state), giving rise to the emission of 2 gamma quanta of roughly 21 keV. The NEMO project deals with 100Mo. The main objective of the NEMO-3 experiment consists in the measurement of the half-life of the neutrinoless double decay of this nuclide (about 1025 years)

  6. Development of segmented germanium detectors for neutrinoless double beta decay experiments

    The results from neutrino oscillation experiments indicate that at least two neutrinos have mass. However, the value of the masses and whether neutrinos and anti-neutrinos are identical, i.e., Majorana particles, remain unknown. Neutrinoless double beta decay experiments can help to improve our understanding in both cases and are the only method currently possible to tackle the second question. The GERmanium Detector Array (GERDA) experiment, which will search for the neutrinoless double beta decay of 76Ge, is currently under construction in Hall A of the INFN Gran Sasso National Laboratory (LNGS), Italy. In order to achieve an extremely low background level, segmented germanium detectors are considered to be operated directly in liquid argon which serves simultaneously as cooling and shielding medium. Several test cryostats were built at the Max-Planck-Institut fuer Physik in Muenchen to operate segmented germanium detectors both in vacuum and submerged in cryogenic liquid. The performance and the background discrimination power of segmented germanium detectors were studied in detail. It was proven for the first time that segmented germanium detectors can be operated stably over long periods submerged in a cryogenic liquid. It was confirmed that the segmentation scheme employed does well in the identification of photon induced background and demonstrated for the first time that also neutron interactions can be identified. The C++ Monte Carlo framework, MaGe (Majorana-GERDA), is a joint development of the Majorana and GERDA collaborations. It is based on GEANT4, but tailored especially to simulate the response of ultra-low background detectors to ionizing radiation. The predictions of the simulation were veri ed to be accurate for a wide range of conditions. Some shortcomings were found and corrected. Pulse shape analysis is complementary to segmentation in identifying background events. Its efficiency can only be correctly determined using reliable pulse shape

  7. Development of segmented germanium detectors for neutrinoless double beta decay experiments

    Liu, Jing

    2009-06-09

    The results from neutrino oscillation experiments indicate that at least two neutrinos have mass. However, the value of the masses and whether neutrinos and anti-neutrinos are identical, i.e., Majorana particles, remain unknown. Neutrinoless double beta decay experiments can help to improve our understanding in both cases and are the only method currently possible to tackle the second question. The GERmanium Detector Array (GERDA) experiment, which will search for the neutrinoless double beta decay of {sup 76}Ge, is currently under construction in Hall A of the INFN Gran Sasso National Laboratory (LNGS), Italy. In order to achieve an extremely low background level, segmented germanium detectors are considered to be operated directly in liquid argon which serves simultaneously as cooling and shielding medium. Several test cryostats were built at the Max-Planck-Institut fuer Physik in Muenchen to operate segmented germanium detectors both in vacuum and submerged in cryogenic liquid. The performance and the background discrimination power of segmented germanium detectors were studied in detail. It was proven for the first time that segmented germanium detectors can be operated stably over long periods submerged in a cryogenic liquid. It was confirmed that the segmentation scheme employed does well in the identification of photon induced background and demonstrated for the first time that also neutron interactions can be identified. The C++ Monte Carlo framework, MaGe (Majorana-GERDA), is a joint development of the Majorana and GERDA collaborations. It is based on GEANT4, but tailored especially to simulate the response of ultra-low background detectors to ionizing radiation. The predictions of the simulation were veri ed to be accurate for a wide range of conditions. Some shortcomings were found and corrected. Pulse shape analysis is complementary to segmentation in identifying background events. Its efficiency can only be correctly determined using reliable pulse

  8. Randomized double-blind trial of beta-carotene and vitamin C in women with minor cervical abnormalities

    Mackerras, D; Irwig, L.; Simpson, J M; Weisberg, E; Cardona, M.; Webster, F.; Walton, L.; Ghersi, D

    1999-01-01

    A double-blind, placebo-controlled, randomized, factorial study using a daily oral administration of 30 mg beta-carotene and/or 500 mg vitamin C was conducted in 141 women with colposcopically and histologically confirmed minor squamous atypia or cervical intra-epithelial neoplasia (CIN) I. Over approximately 2 years of follow-up, 43 lesions regressed to normal and 13 progressed to CIN II. The regression rate was slightly higher, but not significantly so, in those randomized to beta-carotene ...

  9. Radon and material radiopurity assessment for the NEXT double beta decay experiment

    The ”Neutrino Experiment with a Xenon TPC” (NEXT), intended to investigate the neutrinoless double beta decay using a high-pressure xenon gas TPC filled with Xe enriched in 136Xe at the Canfranc Underground Laboratory in Spain, requires ultra-low background conditions demanding an exhaustive control of material radiopurity and environmental radon levels. An extensive material screening process is underway for several years based mainly on gamma-ray spectroscopy using ultra-low background germanium detectors in Canfranc but also on mass spectrometry techniques like GDMS and ICPMS. Components from shielding, pressure vessel, electroluminescence and high voltage elements and energy and tracking readout planes have been analyzed, helping in the final design of the experiment and in the construction of the background model. The latest measurements carried out will be presented and the implication on NEXT of their results will be discussed. The commissioning of the NEW detector, as a first step towards NEXT, has started in Canfranc; in-situ measurements of airborne radon levels were taken there to optimize the system for radon mitigation and will be shown too

  10. Deformed shell model results for neutrinoless double beta decay of nuclei in A = 60 - 90 region

    Nuclear transition matrix elements (NTME) for the neutrinoless double beta decay (Oνββ or OνDBD) of 70Zn, 80Se and 82Se nuclei are calculated within the framework of the deformed shell model (DSM) based on Hartree–Fock (HF) states. For 70Zn, jj44b interaction in 2p3/2, 1f5/2, 2p1/2 and 1g9/2 space with 56Ni as the core is employed. However, for 80Se and 82Se nuclei, a modified Kuo interaction with the above core and model space are employed. Most of our calculations in this region were performed with this effective interaction. However, jj44b interaction has been found to be better for 70Zn. The above model space was used in many recent shell model (SM) and interacting boson model (IBM) calculations for nuclei in this region. After ensuring that DSM gives good description of the spectroscopic properties of low-lying levels in these three nuclei considered, the NTME are calculated. The deduced half-lives with these NTME, assuming neutrino mass is 1 eV, are 1.1 × 1026, 2.3 × 1027 and 2.2 × 1024 yr for 70Zn, 80Se and 82Se, respectively. (author)

  11. Weak decays and double beta decay. Annual progress report, January 1, 1982-December 31, 1982

    Work has continued in collaboration with experimenters from Yale, Brookhaven and Pittsburgh (Brookhaven experiment 702) to measure asymmetries in the decays of polarized Σ+'s into protons and neutral pions and of polarized Σ-'s into neutrons and negative pions. A short experiment was carried out in the Brookhaven AGS A2 test beam to measure the efficiency of a cylindrical shower counter essential for measuring the asymmetry parameter in the rare decay of polarized Σ+'s into protons and gammas. An electronic controller to stabilize the magnetic field of the superconducting, polarized target magnet was also designed and built at Mount Holyoke, and it functioned extremely well during a six week May to June run. Also, the design of an experiment to search for double beta decay in Molybdenum 100 is briefly described. A group consisting of five experimenters from LBL and two from Mount Holyoke hope to make a formal proposal in September to the LBL administration to begin work on this experiment late this year and during the next calendar year

  12. Consistency check of pulse shape discrimination for broad energy germanium detectors using double beta decay data

    The Gerda (GERmanium Detector Array) experiment was built to study fundamental neutrino properties via neutrinoless double beta decay (0νββ). 0νββ events are single-site events (SSE) confined to a scale about millimeter. However, most of backgrounds are multi-site events (MSE). Broad Energy Germanium detectors (BEGes) offer the potential merits of improved pulse shape recognition efficiencies of SSE/MSE. They allow us to reach the goal of Phase II with a background index of 10-3 cts/(keV.kg.yr) in the ROI. BEGe detectors with a total target mass of 3.63 kg have been installed to the Gerda setup in the Laboratori Nazionali del Gran Sasso (LNGS) in July 2012 and are collecting data since. A consistency check of the pulse shape discrimination (PSD) efficiencies by comparison of calibration data and 2νββ data will be presented. The PSD power of these detectors is demonstrated.

  13. Consistency check of pulse shape discrimination for broad energy germanium detectors using double beta decay data

    Liao, Heng-Ye [Max-Planck-Institut fuer Physik, Muenchen (Germany); Collaboration: GERDA-Collaboration

    2013-07-01

    The Gerda (GERmanium Detector Array) experiment was built to study fundamental neutrino properties via neutrinoless double beta decay (0νββ). 0νββ events are single-site events (SSE) confined to a scale about millimeter. However, most of backgrounds are multi-site events (MSE). Broad Energy Germanium detectors (BEGes) offer the potential merits of improved pulse shape recognition efficiencies of SSE/MSE. They allow us to reach the goal of Phase II with a background index of 10{sup -3} cts/(keV.kg.yr) in the ROI. BEGe detectors with a total target mass of 3.63 kg have been installed to the Gerda setup in the Laboratori Nazionali del Gran Sasso (LNGS) in July 2012 and are collecting data since. A consistency check of the pulse shape discrimination (PSD) efficiencies by comparison of calibration data and 2νββ data will be presented. The PSD power of these detectors is demonstrated.

  14. Results on Neutrinoless Double-Beta Decay from Gerda Phase I

    Macolino, Carla

    2014-12-01

    The GERmanium Detector Array, GERDA, is designed to search for neutrinoless double-beta (0νββ) decay of 76Ge and it is installed in the Laboratori Nazionali del Gran Sasso (LNGS) of INFN, Italy. In this review, the detection principle and detector setup of GERDA are described. Also, the main physics results by GERDA Phase I, are discussed. They include the measurement of the half-life of 2νββ decay, the background decomposition of the energy spectrum and the techniques for the discrimination of the background, based on the pulse shape of the signal. In the last part of this review, the estimation of a limit on the half-life of 0νββ (T0ν 1/2>2.1ḑot 1025 yr at 90% C.L.) and the comparison with previous results are discussed. GERDA data from Phase I strongly disfavor the recent claim of 0νββ discovery, based on data from the Heidelberg-Moscow experiment.

  15. GERDA, searching for the neutrinoless double beta decay in 76Ge

    The observation of the neutrinoless double beta decay (0ν2β) would verify the commonly assumed Majorana nature of the neutrino. For a Majorana neutrino this process is possible as the neutrino oscillations proof their non-vanishing mass. Consequently, one needs to extended the Standard Model as the lepton number conservation is violated. Discovery of the 0ν2β decay could possibly resolve the hierarchy problem and set the mass scale for neutrinos. 0ν2β decay is a very rare process (T1/2> 1025 y) which therefore requires extremely low background experimental conditions. 76Ge is well suited for the calorimetric approach where source and detector are identical. The GERDA collaboration has available ∝18 kg of enriched detectors from the previous 0ν2β experiments HdM and IGEX. In contrast to these the GERDA setup relies on a different concept of background suppression: operating the bare diodes in lAr with a large water buffer around, all located at the underground laboratory LNGS. Only screened high purity material after screening is used. The setup will be completed and the measurements start in 2009.

  16. GERDA, searching for the neutrinoless double beta decay in 76Ge

    Full text: The GERDA (GERmanium Detector Array) experiment is designed to search for the neutrino-less double beta decay of 76Ge, which could establish the nature of the neutrino (Dirac or Majorana) and provide information on the absolute neutrino mass. The experiment is currently under construction in the Gran Sasso National Laboratory, the commissioning phase is expected to start in fall 2009. In GERDA phase-I, about 18 kg of enriched-76Ge detectors, previously operated by the Heidelberg-Moscow and IGEX experiments, will be immersed directly in pure liquid Ar, which will act as the cooling medium and as shield against external backgrounds. In phase-II about 20 kg of new enriched detectors will be added. The aim is to collect an exposure of about 100 kg · y with a background of 10-3 counts/(kg · y · keV) at the Q-value of 2039 keV. The status and science prospects of the project will be presented. (author)

  17. Double-beta decay with majoron emission in GERDA Phase I

    Hemmer, Sabine

    2015-07-01

    Neutrinoless double-beta decay with emission of one or two majorons (0 νββχ( χ)) is predicted by several beyond-Standard-Model theories. This article reviews the results of a search for 0 νββχ( χ) of 76Ge using data from the Germanium Detector Array (GERDA) experiment, located underground at the INFN Laboratori Nazionali del Gran Sasso (LNGS) in Italy. The analysis comprised data with an exposure of 20.3 kg·yr from the first phase of the experiment. No indication of contributions to the observed energy spectra was detected for any of the majoron models. The lower limit on the half-life for the ordinary majoron model (spectral index n = 1 was determined to be T {1/2/0 νβ } > 4.2 · 1023 yr (90% quantile). This limit and the limits derived for the other majoron modes constitute the most stringent limits on 0 νββχ( χ) decay of 76Ge measured to date.

  18. Search for Neutrinoless Double Beta Decay of 76Ge with the GERmanium Detector Array "gerda"

    Garfagnini, Alberto

    2011-10-01

    The study of neutrinoless double beta decay (DBD) is the only presently known approach to the fundamental question if the neutrino is a Majorana particle, i.e. its own anti-particle. The observation of neutrinoless DBD would not only establish the Majorana nature of the neutrino but also represent a determination of its effective mass if the nuclear matrix element is given. So far, the most sensitive results have been obtained with 76Ge, and the group of Klapdor-Kleingrothaus has made a claim of discovery. Future experiments have to reduce radioactive backgrounds to increase the sensitivity. GERDA is a new DBD experiment which is currently under construction in the INFN Gran Sasso National Laboratory, Italy. It is implementing a new shielding concept by operating bare Ge diodes - enriched in 76Ge - in high purity liquid argon supplemented by a water shield. The aim of GERDA is to scrutinize the recent claim of discovery, and, in a second phase, to achieve a two orders of magnitude lower background index than recent experiments, increasing the sensitive mass and reaching an exposure of 100 kg yr. The paper will discuss design, physics reach, and status of construction of GERDA.

  19. The MGDO software library for data analysis in Ge neutrinoless double-beta decay experiments

    The Gerda and Majorana experiments will search for neutrinoless double-beta decay of 76Ge using isotopically enriched high-purity germanium detectors. Although the experiments differ in conceptual design, they share many aspects in common, and in particular will employ similar data analysis techniques. The collaborations are jointly developing a C++ software library, MGDO, which contains a set of data objects and interfaces to encapsulate, store and manage physical quantities of interest, such as waveforms and high-purity germanium detector geometries. These data objects define a common format for persistent data, whether it is generated by Monte Carlo simulations or an experimental apparatus, to reduce code duplication and to ease the exchange of information between detector systems. MGDO also includes general-purpose analysis tools that can be used for the processing of measured or simulated digital signals. The MGDO design is based on the Object-Oriented programming paradigm and is very flexible, allowing for easy extension and customization of the components. The tools provided by the MGDO libraries are used by both Gerda and Majorana.

  20. Radon-induced surface contaminations in neutrinoless double beta decay and dark matter experiments

    In experiments looking for rare events, like neutrinoless double beta decay (DBD0ν) and dark matter search (DM), one of the main issues is to increase the experimental sensitivity through the material selection and production. The background contribution coming from the materials used for the detector realization has to be minimized. Moreover the net reduction of the background produced by the bulk part of the apparatus has raised concerns about the background contribution coming from the surfaces. Many procedures and techniques were developed during the last years in order to remove and to minimize the presence of possible contaminants on detector surfaces. To succeed in this strategy a big effort was put in defining all possible mechanisms that lead to surface contaminations, as well as specific cleaning procedures, which are able to reduce and control the surface radioactivity. The presence in air and gases of possible radioactive elements that can stick on the detector surfaces can lead to a recontamination process that will vanish all the applied cleaning procedures. Here is presented and analyzed the contribution to the background of rare events experiments like CUORE experiment (DBD0ν) and EDELWEISS experiment (DM) produced by an exposure of their detector components to a big activity of 222Rn, radioactive daughter isotope from the 238U chain. (author)

  1. A Novel Point Contact HPGe Detector for Searching for Neutrinoless Double-Beta Decay

    Gehman, Victor M.

    2008-10-01

    The Majo-ra-na collaboration is investigating a new design for high-purity germanium (HPGe) detectors that could increase the physics reach and decrease the cost of our next generation neutrinoless double-beta decay (0νββ) search. The p-type, point-contact (PPC) HPGe detector (that is, a detector with a very compact central contact geometry), has a number of very attractive characteristics which could do much to help the field of 0νββ, as well as the search for many other types of rare events. This new detector design allows for very low energy thresholds (potentially as low as 0.1 keV), and powerful background rejection through comparatively simple pulse shape analysis algorithms using only the digitized signal from the central contact. As with any new technology however, the PPC detectors must be characterized for reliability, robustness and reproducible fabrication. We present the current status of our efforts, with emphasis on one such detector, ``MJ70'' procured for the Majo-ra-na collaboration from PHDs Co. This detector is currently undergoing careful evaluation. This presentation will focus on the characterization program for PPCs, as well as how these detectors fit into the broader Majo-ra-na R&D program.

  2. Search for double beta decay of 106Cd in the TGV-2 experiment

    Rukhadze, N. I.; Brudanin, V. B.; Egorov, V. G.; Klimenko, A. A.; Kovalik, A.; Kouba, P.; Piquemal, F.; Rozov, S. V.; Rukhadze, E.; Salamatin, A. V.; Šimkovic, F.; Shitov, Yu A.; Štekl, I.; Timkin, V. V.; Yakushev, E. A.

    2016-05-01

    A new experimental run of searching for double beta decay of 106Cd was performed at the Modane underground laboratory (LSM, France, 4800 m w.e.) using the TGV-2 spectrometer, consisting of 32 planar type HPGe detectors with a total sensitive volume of ~400 cm3. 16 foils of 106Cd with an enrichment of 99.57% and a total mass of ~ 23.2 g were inserted between the entrance windows of face-to-face detectors. The limit on 2vEC/EC decay of 106Cd - T1/2 > 3.7 × 1020 y at 90% C.F was obtained from the preliminary calculation of experimental data accumulated for 8198 h of measurement. The limits on the resonance OvEC/EC decay of 106Cd were obtained from the measurement of ~23.2 g of 106Cd with the low-background HPGe spectrometer Obelix lasted 395 h -T1/2 (KF, 2741 keV) > 0.9 × 1020 y and T1/2 (KK, 2718 keV) > 1.4 × 1020 y at 90% C.L.

  3. Search for double beta decay of 106Cd in TGV-2 experiment

    Search for double beta decay (β+β+, β+/EC, EC/EC) of 106Cd was performed at the Modane underground laboratory (4800 m w.e.) using a spectrometer TGV-2 with 32 HPGe detectors. New limits on the half-lives of 0vEC/EC resonant decay - T1/2 ≥ 1.6 x 1020 y, and on 2vEC/EC decay of 106Cd - T1/2 ≥ 4.1 x 1020 y (at 90% CL) were obtained from preliminary calculations of experimental data accumulated for 12900 h of measurement of ∼13.6 g of 106Cd with enrichment of 75%. The limits on 2vEC/EC decay of 106Cd to the 2+,512 keV and 0+1,1334 keV excited states of 106Pd and on 2vβ+β+ and 2vβ+/EC decay of 106Cd were improved

  4. Search for double beta decay of 106Cd in TGV-2 experiment

    Rukhadze, N. I.; Briançon, Ch; Brudanin, V. B.; Čermák, P.; Egorov, V. G.; Klimenko, A. A.; Kovalik, A.; Shitov, Yu A.; Štekl, I.; Timkin, V. V.; Vylov, Ts

    2010-01-01

    Search for double beta decay (β+β+, β+/EC, EC/EC) of 106Cd was performed at the Modane underground laboratory (4800 m w.e.) using a spectrometer TGV-2 with 32 HPGe detectors. New limits on the half-lives of 0vEC/EC resonant decay - T1/2 >= 1.6 × 1020 y, and on 2vEC/EC decay of 106Cd - T1/2 >= 4.1 × 1020 y (at 90% CL) were obtained from preliminary calculations of experimental data accumulated for 12900 h of measurement of ~13.6 g of 106Cd with enrichment of 75%. The limits on 2vEC/EC decay of 106Cd to the 2+,512 keV and 0+1,1334 keV excited states of 106Pd and on 2vβ+β+ and 2vβ+/EC decay of 106Cd were improved

  5. The NEXT-100 experiment for neutrinoless double beta decay searches (Conceptual Design Report)

    Álvarez, V; Batallé, M; Bayarri, J; Borges, F I G; Cárcel, S; Carmona, J M; Castel, J; Catalá, J M; Cebrián, S; Cervera-Villanueva, A; Chan, D; Conde, C A N; Dafni, T; Dias, T H V T; Díaz, J; Esteve, R; Evtoukhovitch, P; Fernandes, L M P; Ferrario, P; Ferrer-Ribas, E; Ferreira, A L; Freitas, E D C; Gil, A; Giomataris, I; Goldschmidt, A; Gómez, E; Gómez, H; Gómez-Cadenas, J J; Gónzález, K; Gutiérrez, R M; Hernando-Morata, J A; Herrera, D C; Herrero, V; Iguaz, F; Irastorza, I G; Kalinnikov, V; Kustov, A; Liubarsky, I; Lopes, J A M; Lorca, D; Losada, M; Luzón, G; Martín-Albo, J; Méndez, A; Miller, T; Moisenko, A; Mols, J P; Monrabal, F; Monteiro, C M B; Monzó, J M; Mora, F J; Muñoz-Vidal, J; da Luz, H Natal; Navarro, G; Nebot, M; Nygren, D; Oliveira, C A B; Palma, R; Pérez-Aparicio, J L; Renner, J; Ripoll, L; Rodríguez, A; Rodríguez, J; Santos, F P; Santos, J M F dos; Seguí, L; Serra, L; Sofka, C; Sorel, M; Spieler, H; Toledo, J F; Tomás, A; Tsamalaidze, Z; Vázquez, D; Velicheva, E; Veloso, J F C A; Villar, J A; Webb, R; Weber, T; White, J; Yahlali, N

    2011-01-01

    We propose an EASY (Electroluminescent ApparatuS of high Yield) and SOFT (Separated Optimized FuncTion) time-projection chamber for the NEXT experiment, that will search for neutrinoless double beta decay (bb0nu) in Xe-136. Our experiment must be competitive with the new generation of bb0nu searches already in operation or in construction. This requires a detector with very good energy resolution (<1%), very low background con- tamination (1E-4 counts/(keV \\bullet kg \\bullet y)) and large target mass. In addition, it needs to be operational as soon as possible. The design described here optimizes energy resolution thanks to the use of proportional electroluminescent amplification (EL); it is compact, as the Xe gas is under high pressure; and it allows the measurement of the topological signature of the event to further reduce the background contamination. The SOFT design uses different sensors for tracking and calorimetry. We propose the use of SiPMs (MPPCs) coated with a suitable wavelength shifter for th...

  6. The contribution of light Majorana neutrinos to neutrinoless double beta decay and cosmology

    Dell’Oro, S.; Marcocci, S. [INFN, Gran Sasso Science Institute,Viale F. Crispi 7, 67100 L’Aquila (Italy); Viel, M. [INAF, Osservatorio Astronomico di Trieste,Via G.B. Tiepolo 11, 34131 Trieste (Italy); INFN, Sezione di Trieste,Via Valerio 2, 34127 Trieste (Italy); Vissani, F. [INFN, Laboratori Nazionali del Gran Sasso,Via G. Acitelli 22, 67100 Assergi (AQ) (Italy); INFN, Gran Sasso Science Institute,Viale F. Crispi 7, 67100 L’Aquila (Italy)

    2015-12-11

    Cosmology is making impressive progress and it is producing stringent bounds on the sum of the neutrino masses Σ, a parameter of great importance for the current laboratory experiments. In this letter, we exploit the potential relevance of the analysis of Palanque-Delabrouille et al. to the neutrinoless double beta decay (0νββ) search. This analysis indicates small values for the lightest neutrino mass, since the authors find Σ<84 meV at 1σ C.L., and provides a 1σ preference for the normal hierarchy. The allowed values for the Majorana effective mass, probed by 0νββ, turn out to be <75 meV at 3σ C.L. and lower down to less than 20 meV at 1σ C.L. . If this indication is confirmed, the impact on the 0νββ experiments will be tremendous since the possibility of detecting a signal will be out of the reach of the next generation of experiments.

  7. Extracting Majorana Properties in the Throat of Neutrinoless Double Beta Decay

    Ge, Shao-Feng

    2016-01-01

    Assuming that neutrinos are Majorana particles, we explore what information can be inferred from future strong limits (i.e. non-observation) for neutrinoless double beta decay. Specifically we consider the case where the mass hierarchy is normal and the different contributions to the effective mass $\\langle m \\rangle_{ee}$ partly cancel. We discuss how this fixes the two Majorana CP phases simultaneously from the Majorana Triangle and how it limits the lightest neutrino mass $m_1$ within a narrow window. The two Majorana CP phases are in this case even better determined than in the usual case for larger $\\langle m \\rangle_{ee}$. We show that the uncertainty in these predictions can be significantly reduced by the complementary measurement of reactor neutrino experiments, especially the medium baseline version JUNO/RENO-50. We also estimate the necessary precision on $\\langle m \\rangle_{ee}$ to infer non-trivial Majorana CP phases and the upper limit $\\langle m \\rangle_{ee} \\lesssim 1\\,\\mbox{meV}$ sets a targe...

  8. LUCIFER: a scintillating bolometer array for the search of neutrinoless double beta decay

    In spite of the high precision achieved in the field of neutrino oscillations, there are some fundamental questions that can not be addressed by a study of ths phenomenon. We do not know in fact the absolute mass of neutrino and weather it is a Dirac or a Majorana particle. The LUCIFER experiment, financed by the ERC-AdG, will play an important role in this field. This project aims to push beyond the actual technological limits the possibility of observation of the Neutrinoless Double Beta Decay (0νDBD). The detection of this extremely rare decay would indeed demonstrate that neutrino is a Majorana particle and, at the same time, would allow to set its absolute mass scale. LUCIFER will study the 0νDBD do 82Se through ZnSe scintillating bolometers. Thanks to the simultaneous red-out of the heat and light produced by an interaction in the crystal, the background rate in the region of interest will be lower than 10-3 counts/kg/keV/years. In the following, the expected performance of LUCIFER are discussed.

  9. LUCIFER: Scintillating bolometers for the search of Neutrinoless Double Beta Decay

    The nature of neutrino mass is one of the frontier problems of particle physics. Neutrinoless Double Beta Decay (0νDBD) is a powerful tool to measure the neutrino mass and to test possible extensions of the Standard Model. Bolometers are excellent detectors to search for this rare decay, thanks to their good energy resolution and to the low background conditions in which they can operate. The current challenge consists in the reduction of the background, represented by environmental γ's and α's, in view of a zero background experiment. We present the LUCIFER R and D, funded by an European grant, in which the background can be reduced by an order of magnitude with respect to the present generation experiments. The technique is based on the simultaneous bolometric measurement of the heat and of the scintillation light produced by a particle, that allows to discriminate between β and α particles. The γ background is reduced by choosing 0νDBD candidate isotopes with transition energy above the environmental γ's spectrum. The prospect of this R and D are discussed.

  10. LUCIFER: Scintillating bolometers for the search of Neutrinoless Double Beta Decay

    Vignati, M.

    2012-08-01

    The nature of neutrino mass is one of the frontier problems of particle physics. Neutrinoless Double Beta Decay (0νDBD) is a powerful tool to measure the neutrino mass and to test possible extensions of the Standard Model. Bolometers are excellent detectors to search for this rare decay, thanks to their good energy resolution and to the low background conditions in which they can operate. The current challenge consists in the reduction of the background, represented by environmental γ's and α's, in view of a zero background experiment. We present the LUCIFER R&D, funded by an European grant, in which the background can be reduced by an order of magnitude with respect to the present generation experiments. The technique is based on the simultaneous bolometric measurement of the heat and of the scintillation light produced by a particle, that allows to discriminate between β and α particles. The γ background is reduced by choosing 0νDBD candidate isotopes with transition energy above the environmental γ's spectrum. The prospect of this R&D are discussed.

  11. Ultra-low gamma-ray measurement system for neutrinoless double beta decay

    An experiment for the detection of 0νβ+/EC and 0νEC/EC in 92Mo nuclei has been carried out with a scintillating crystal, CaMoO4, in coincidence with the HPGe detector. We study the background events inside the event selection window for 0ν β+/EC decays of CaMoO4 detector. For 51.2 days of data taking period, we didn't observe any event in the neutrinoless EC/EC decay event window. The 92Mo 0νβ+/EC decay half-life limit was set to 0.61×1020 years with a 90% confidence by method of Feldman and Cousins. This ultra-low gamma ray measurement utilizing coincidence technique can be used for the resonant EC/EC decay process of some nuclei which is potentially important for neutrinoless double beta decay process. - Highlights: • 0νββ experiment is the only practical way to study the nature of neutrino mass. • We performed a 0νββ experiment with a HPGe detector and a CaMoO4 crystal. • The limit of the half-life of the 0νβ+/EC is 0.61×1020 years at 90% CL

  12. Sterile Neutrinos, Dominant Seesaw Mechanisms, Double Beta Decay, and Other Predictions

    Parida, M K

    2016-01-01

    In a recent review Mohapatra has discussed how type-I seesaw mechanism suppressed by fine tuning of Yukawa cpuplings, or specific textures of associated fermion mass matrices, can form the basis of neutrino masses in TeV scale $W_R$ boson models. In this paper we review recent works in another class of theories where the added presence of fermion singlets manifesting as sterile neutrinos render the type-I seesaw contribution vanishing but extended seesaw dominant where the light neutrino mass formula is same as the inverse seesaw but all massive neutrinos are Majorana fermions. We discuss how this cancellation criteria has led to a new mechanism of type-II seesaw dominance which also permits $U(1)_{B-L}$ breaking scale much smaller than the left-handed triplet mass and accessible to direct experimental tests. Out of a number of new observable predictions, the most visible one in both cases is the dominant contribution to double beta decay mediated by light sterile neutrinos in the $W_L-W_L$ channel. This sees...

  13. The contribution of light Majorana neutrinos to neutrinoless double beta decay and cosmology

    Cosmology is making impressive progress and it is producing stringent bounds on the sum of the neutrino masses Σ, a parameter of great importance for the current laboratory experiments. In this letter, we exploit the potential relevance of the analysis of Palanque-Delabrouille et al. to the neutrinoless double beta decay (0νββ) search. This analysis indicates small values for the lightest neutrino mass, since the authors find Σ<84 meV at 1σ C.L., and provides a 1σ preference for the normal hierarchy. The allowed values for the Majorana effective mass, probed by 0νββ, turn out to be <75 meV at 3σ C.L. and lower down to less than 20 meV at 1σ C.L. . If this indication is confirmed, the impact on the 0νββ experiments will be tremendous since the possibility of detecting a signal will be out of the reach of the next generation of experiments

  14. Exploring the neutrinoless double beta decay in the inverted neutrino hierarchy with bolometric detectors

    Artusa, D.R. [University of South Carolina, Department of Physics and Astronomy, Columbia, SC (United States); INFN-Laboratori Nazionali del Gran Sasso, Assergi, L' Aquila (Italy); Avignone, F.T.; Chott, N.; Creswick, R.J.; Farach, H.A.; Rosenfeld, C.; Wilson, J. [University of South Carolina, Department of Physics and Astronomy, Columbia, SC (United States); Azzolini, O.; Camacho, A.; De Biasi, A.; Keppel, G.; Palmieri, V.; Pira, C.; Rampazzo, V. [INFN-Laboratori Nazionali di Legnaro, Legnaro, Padua (Italy); Balata, M.; Bucci, C.; Canonica, L.; Casali, N.; Di Vacri, M.L.; Goett, J.; Gorla, P.; Nisi, S.; Orlandi, D.; Pattavina, L.; Pirro, S.; Zarra, C. [INFN-Laboratori Nazionali del Gran Sasso, Assergi, L' Aquila (Italy); Banks, T.I. [INFN-Laboratori Nazionali del Gran Sasso, Assergi, L' Aquila (Italy); University of California, Department of Physics, Berkeley, CA (United States); Lawrence Berkeley National Laboratory, Nuclear Science Division, Berkeley, CA (United States); Bari, G.; Deninno, M.M.; Moggi, N. [INFN-Sezione di Bologna, Bologna (Italy); Beeman, J. [Lawrence Berkeley National Laboratory, Materials Science Division, Berkeley, CA (United States); Bellini, F.; Cardani, L.; Cosmelli, C.; Ferroni, F.; Piperno, G. [Sapienza Universita di Roma, Dipartimento di Fisica, Rome (Italy); INFN-Sezione di Roma, Rome (Italy); Bersani, A. [INFN-Sezione di Genova, Genoa (Italy); Biassoni, M.; Brofferio, C.; Capelli, S.; Carrettoni, M.; Chiesa, D.; Clemenza, M.; Faverzani, M.; Ferri, E.; Fiorini, E.; Giachero, A.; Gironi, L.; Gotti, C.; Maiano, C.; Maino, M.; Nucciotti, A.; Pavan, M.; Sala, E.; Sisti, M.; Terranova, F.; Zanotti, L. [Universita di Milano-Bicocca, Dipartimento di Fisica, Milan (Italy); INFN-Sezione di Milano Bicocca, Milan (Italy); Cai, X.Z.; Cao, X.G.; Fang, D.Q.; Li, Y.L.; Ma, Y.G.; Tian, W.D.; Wang, H.W. [Chinese Academy of Sciences, Shanghai Institute of Applied Physics, Shanghai (China); Carbone, L.; Cremonesi, O.; Datskov, V.; Pessina, G.; Previtali, E.; Rusconi, C. [INFN-Sezione di Milano Bicocca, Milan (Italy); Dafinei, I.; Morganti, S.; Orio, F.; Pettinacci, V.; Tomei, C.; Vignati, M. [INFN-Sezione di Roma, Rome (Italy); Dally, A.; Ejzak, L.; Wielgus, L. [University of Wisconsin, Department of Physics, Madison, WI (United States); Di Domizio, S.; Fernandes, G.; Pallavicini, M. [INFN-Sezione di Genova, Genoa (Italy); Universita di Genova, Dipartimento di Fisica, Genoa (Italy); Franceschi, M.A.; Ligi, C.; Napolitano, T. [INFN-Laboratori Nazionali di Frascati, Frascati, Rome (Italy); Freedman, S.J. [University of California, Department of Physics, Berkeley, CA (United States); Lawrence Berkeley National Laboratory, Nuclear Science Division, Berkeley, CA (United States); Fujikawa, B.K.; Han, K.; Mei, Y.; Smith, A.R. [Lawrence Berkeley National Laboratory, Nuclear Science Division, Berkeley, CA (United States); Giuliani, A.; Tenconi, M. [Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse, Orsay (France); Gutierrez, T.D. [California Polytechnic State University, Physics Department, San Luis Obispo, CA (United States); Haller, E.E. [Lawrence Berkeley National Laboratory, Materials Science Division, Berkeley, CA (United States); University of California, Department of Materials Science and Engineering, Berkeley, CA (United States); Heeger, K.M.; Maruyama, R.H. [Yale University, Department of Physics, New Haven, CT (United States); Hennings-Yeomans, R.; O' Donnell, T. [University of California, Department of Physics, Berkeley, CA (United States); Huang, H.Z.; Liu, X.; Trentalange, S.; Winslow, L.A.; Zhu, B.X. [University of California, Department of Physics and Astronomy, Los Angeles, CA (United States); Kadel, R. [Lawrence Berkeley National Laboratory, Physics Division, Berkeley, CA (United States); Kazkaz, K.; Pedretti, M.; Sangiorgio, S.; Scielzo, N.D. [Lawrence Livermore National Laboratory, Livermore, CA (United States); Kolomensky, Yu.G. [University of California, Department of Physics, Berkeley, CA (United States); Lawrence Berkeley National Laboratory, Physics Division, Berkeley, CA (United States); Martinez, M. [Universidad de Zaragoza, Laboratorio de Fisica Nuclear y Astroparticulas, Saragossa (Spain); Nones, C. [CEA/Saclay, Service de Physique des Particules, Gif-sur-Yvette (France); Norman, E.B.; Wang, B.S. [Lawrence Livermore National Laboratory, Livermore, CA (United States); University of California, Department of Nuclear Engineering, Berkeley, CA (United States); Ouellet, J.L. [University of California, Department of Physics, Berkeley, CA (United States); Lawrence Berkeley National Laboratory, Nuclear Science Division, Berkeley, CA (United States); Taffarello, L. [INFN-Sezione di Padova, Padua (Italy); Ventura, G. [Universita di Firenze, Dipartimento di Fisica, Florence (Italy); INFN-Sezione di Firenze, Florence (Italy); Wise, T. [University of Wisconsin, Department of Physics, Madison, WI (United States); Yale University, Department of Physics, New Haven, CT (United States); Woodcraft, A. [University of Edinburgh, SUPA, Institute for Astronomy, Edinburgh (United Kingdom); Zucchelli, S. [INFN-Sezione di Bologna, Bologna (Italy); Universita di Bologna, Dipartimento di Fisica, Bologna (Italy)

    2014-10-15

    Neutrinoless double beta decay (0νββ) is one of the most sensitive probes for physics beyond the Standard Model, providing unique information on the nature of neutrinos. In this paper we review the status and outlook for bolometric 0νββ decay searches. We summarize recent advances in background suppression demonstrated using bolometers with simultaneous readout of heat and light signals. We simulate several configurations of a future CUORE-like bolometer array which would utilize these improvements and present the sensitivity reach of a hypothetical next-generation bolometric 0νββ experiment. We demonstrate that a bolometric experiment with the isotope mass of about 1 ton is capable of reaching the sensitivity to the effective Majorana neutrino mass (vertical stroke m{sub ee} vertical stroke) of order 10-20 meV, thus completely exploring the so-called inverted neutrino mass hierarchy region. We highlight the main challenges and identify priorities for an R and D program addressing them. (orig.)

  15. Double beta decay of molybdenum 100. Annual progress report, January 1, 1985-December 31, 1985

    Work is continuing on a collaborative experiment with experimenters from the Lawrence Berkeley Laboratory to search for neutrinoless double beta decay in molybdenum 100. Currently testing a stack of 16 silicon hybrid lithium drift-surface barrier and 6 high purity silicon detectors in a second generation titanium cryostat at the Lawrence Berkeley Laboratory Low Level Counting Facility. Preliminary data indicates that the system background rate in the vicinity of 3.033 MeV energy release molybdenum 100 is about 3 events/(year)(kg of Si)(keV), a factor of 10 improvement over our earlier run in August 1984 with 5 detectors, and about a factor of 10 lower than the reported background rate of 33 events/(year)(kg of Ge)(keV) taken with a germanium detector above ground by Avignone et al. in their clean cryostat under similar conditions. Approximately 50 additional lithium drift silicon detectors are under construction and silicon for another 50 detectors is on order. Development work is also continuing on high purity silicon detectors. It now looks like .5 mm thick large area (about 45 cm2) detectors are within our fabrication capabilities. Cost reduced on readout electronics significantly by combining commercial and homemade circuits, and had no significant technical problems increasing the number of detectors in the array from 5 to 22

  16. GraXe, graphene and xenon for neutrinoless double beta decay searches

    Gomez-Cadenas, J J; Fogler, M M; Katsnelson, M I; Martin-Albo, J; Monrabal, F; Muñoz-Vidal, J

    2011-01-01

    We propose a new detector concept, GraXe (to be pronounced as grace), to search for neutrinoless double beta decay in Xe-136. GraXe combines a popular detection medium in rare-event searches, liquid xenon, with a new, background-free material, graphene. Our baseline design of GraXe is a balloon made of graphene (possibly held together with a very thin structure made of radiopure fiber) and filled with xenon enriched in the Xe-136 isotope. The balloon is immersed in a large tank containing 20 tons of natural liquid xenon and instrumented with large photomultipliers. Liquid xenon is an excellent scintillator, reasonably transparent to its own light. Graphene is transparent over a large frequency range, an impermeable to the xenon. External backgrounds would be shielded by the buffer liquid xenon, and the inner volume has virtually zero background. Industrial graphene can be manufactured at a competitive cost to produce the inner balloon, and there is already near one ton of enriched Xenon available in the world...

  17. Radiopurity assessment of the tracking readout for the NEXT double beta decay experiment

    Cebrián, S.; Pérez, J.; Bandac, I.; Labarga, L.; Álvarez, V.; Barrado, A. I.; Bettini, A.; Borges, F. I. G. M.; Camargo, M.; Cárcel, S.; Cervera, A.; Conde, C. A. N.; Conde, E.; Dafni, T.; Díaz, J.; Esteve, R.; Fernandes, L. M. P.; Fernández, M.; Ferrario, P.; Ferreira, A. L.; Freitas, E. D. C.; Gehman, V. M.; Goldschmidt, A.; Gómez-Cadenas, J. J.; González-Díaz, D.; Gutiérrez, R. M.; Hauptman, J.; Hernando Morata, J. A.; Herrera, D. C.; Irastorza, I. G.; Laing, A.; Liubarsky, I.; López-March, N.; Lorca, D.; Losada, M.; Luzón, G.; Marí, A.; Martín-Albo, J.; Martínez, A.; Martínez-Lema, G.; Miller, T.; Monrabal, F.; Monserrate, M.; Monteiro, C. M. B.; Mora, F. J.; Moutinho, L. M.; Muñoz Vidal, J.; Nebot-Guinot, M.; Nygren, D.; Oliveira, C. A. B.; Ortiz de Solórzano, A.; Pérez Aparicio, J. L.; Querol, M.; Renner, J.; Ripoll, L.; Rodríguez, J.; Santos, F. P.; dos Santos, J. M. F.; Serra, L.; Shuman, D.; Simón, A.; Sofka, C.; Sorel, M.; Toledo, J. F.; Torrent, J.; Tsamalaidze, Z.; Veloso, J. F. C. A.; Villar, J. A.; Webb, R. C.; White, J. T.; Yahlali, N.

    2015-05-01

    The ``Neutrino Experiment with a Xenon Time-Projection Chamber'' (NEXT) is intended to investigate the neutrinoless double beta decay of 136Xe, which requires a severe suppression of potential backgrounds; therefore, an extensive screening and selection process is underway to control the radiopurity levels of the materials to be used in the experimental set-up of NEXT. The detector design combines the measurement of the topological signature of the event for background discrimination with the energy resolution optimization. Separate energy and tracking readout planes are based on different sensors: photomultiplier tubes for calorimetry and silicon multi-pixel photon counters for tracking. The design of a radiopure tracking plane, in direct contact with the gas detector medium, was specially challenging since the needed components like printed circuit boards, connectors, sensors or capacitors have typically, according to available information in databases and in the literature, activities too large for experiments requiring ultra-low background conditions. Here, the radiopurity assessment of tracking readout components based on gamma-ray spectroscopy using ultra-low background germanium detectors at the Laboratorio Subterr&aposaneo de Canfranc (Spain) is described. According to the obtained results, radiopure enough printed circuit boards made of kapton and copper, silicon photomultipliers and other required components, fulfilling the requirement of an overall background level in the region of interest of at most 8×10-4 counts keV-1 kg-1 y-1, have been identified.

  18. Radiopurity assessment of the tracking readout for the NEXT double beta decay experiment

    The ''Neutrino Experiment with a Xenon Time-Projection Chamber'' (NEXT) is intended to investigate the neutrinoless double beta decay of 136Xe, which requires a severe suppression of potential backgrounds; therefore, an extensive screening and selection process is underway to control the radiopurity levels of the materials to be used in the experimental set-up of NEXT. The detector design combines the measurement of the topological signature of the event for background discrimination with the energy resolution optimization. Separate energy and tracking readout planes are based on different sensors: photomultiplier tubes for calorimetry and silicon multi-pixel photon counters for tracking. The design of a radiopure tracking plane, in direct contact with the gas detector medium, was specially challenging since the needed components like printed circuit boards, connectors, sensors or capacitors have typically, according to available information in databases and in the literature, activities too large for experiments requiring ultra-low background conditions. Here, the radiopurity assessment of tracking readout components based on gamma-ray spectroscopy using ultra-low background germanium detectors at the Laboratorio Subterr and apos;aneo de Canfranc (Spain) is described. According to the obtained results, radiopure enough printed circuit boards made of kapton and copper, silicon photomultipliers and other required components, fulfilling the requirement of an overall background level in the region of interest of at most 8×10−4 counts keV−1 kg−1 y−1, have been identified

  19. Octupole correlations in low-lying states of 150Nd and 150Sm and their impact on neutrinoless double-beta decay

    Yao, J M

    2016-01-01

    We present a generator-coordinate calculation, based on a relativistic energy-density functional, of the low-lying spectra in the isotopes $^{150}$Nd and $^{150}$Sm and of the nuclear matrix element that governs the neutrinoless double-beta decay of the first isotope to the second. We carefully examine the impact of octupole correlations on both nuclear structure and the double-beta decay matrix element. Octupole correlations turn out to reduce quadrupole collectivity in both nuclei. Shape fluctuations, however, dilute the effects of octupole deformation on the double-beta decay matrix element, so that the overall octupole-induced quenching is only about 7\\%.

  20. A setup for Ba-ion extraction from high pressure Xe gas for double-beta decay studies with EXO

    Brunner, T., E-mail: tbrunner@stanford.edu [Dept. of Physics, Stanford University, Stanford, CA (United States); Fudenberg, D.; Sabourov, A. [Dept. of Physics, Stanford University, Stanford, CA (United States); Varentsov, V.L. [Institute for Theoretical and Experimental Physics, Moscow (Russian Federation); Facility for Antiproton and Ion Research in Europe (FAIR), Darmstadt (Germany); Gratta, G. [Dept. of Physics, Stanford University, Stanford, CA (United States); Sinclair, D. [Dept. of Physics, Carleton University, Ottawa, ON (Canada); TRIUMF, Vancouver, BC (Canada)

    2013-12-15

    An experimental setup is being developed to extract Ba ions from a high-pressure Xe gas environment. It aims to transport Ba ions from 10 bar Xe to vacuum conditions. The setup utilizes a converging–diverging nozzle in combination with a radio-frequency (RF) funnel to move Ba ions into vacuum through the pressure drop of several orders of magnitude. This technique is intended for use in a future multi-ton detector investigating double-beta decay in {sup 136}Xe. Efficient extraction and detection of Ba ions, the decay product of {sup 136}Xe, would allow for a background-free measurement of the {sup 136}Xe double-beta decay.

  1. A CaMoO4 Crystal Low Temperature Detector for the AMoRE Neutrinoless Double Beta Decay Search

    We report the development of a CaMoO4 crystal low temperature detector for the AMoRE neutrinoless double beta decay (0νββ) search experiment. The prototype detector cell was composed of a 216 g CaMoO4 crystal and a metallic magnetic calorimeter. An overground measurement demonstrated FWHM resolution of 6–11 keV for full absorption gamma peaks. Pulse shape discrimination was clearly demonstrated in the phonon signals, and 7.6 σ of discrimination power was found for the α and β/γ separation. The phonon signals showed rise-times of about 1 ms. It is expected that the relatively fast rise-time will increase the rejection efficiency of two-neutrino double beta decay pile-up events which can be one of the major background sources in 0νββ searches

  2. Background reduction in neutrinoless double beta decay experiments using segmented detectors-A Monte Carlo study for the GERDA setup

    The identification of gamma radiation is essential for a new generation of double beta decay experiments. The GERmanium Detector Array, GERDA, located at the INFN Gran Sasso National Laboratory (LNGS) in Italy, uses germanium, enriched in Ge76, as source and detector, and aims at a background level of less than 10-3counts/(kgkeVy) in the region of the Qββ-value. For the first time highly segmented detectors will be installed in a double beta decay experiment. A detailed GEANT4 Monte Carlo study was performed to evaluate the background reduction achievable by anti-coincidence cuts between crystals and segments. Within the overall geometry of GERDA, the segmentation scheme considered here provides around an order of magnitude of extra background reduction

  3. Pattern recognition of $^{136}$Xe double beta decay events and background discrimination in a high pressure Xenon TPC

    Cebrian, S; Gomez, H; Herrera, D C; Iguaz, F J; Irastorza, I G; Luzon, G; Segui, L; Tomas, A

    2013-01-01

    High pressure gas detectors offer advantages for the detection of rare events, where background reduction is crucial. For the neutrinoless double beta decay of 136Xe a high pressure xenon gas Time Projection Chamber (TPC) combines a good energy resolution and a detailed topological information of each event. The ionization topology of the double beta decay event of 136Xe in gaseous xenon has a characteristic shape defined by the two straggling electron tracks ending up in two higher ionization charge density blobs. With a properly pixelized readout, this topological information is invaluable to perform powerful background discrimination. In this study we carry out detailed simulations of the signal topology, as well as the competing topologies from gamma events that typically compose the background at these energies. We define observables based on graph theory concepts and develop automated discrimination algorithms which reduce the background level in around three orders of magnitude while keeping signal eff...

  4. Testing Left-Right extensions of the standard model of electroweak interactions with double-beta decay and LHC measurements

    Civitarese, O.; Suhonen, J.; Zuber, K.

    2015-07-01

    The minimal extension of the standard model of electroweak interactions allows for massive neutrinos, a massive right-handed boson WR, and a left-right mixing angle ζ. While an estimate of the light (electron) neutrino can be extracted from the non-observation of the neutrinoless double beta decay, the limits on the mixing angle and the mass of the righthanded (RH) boson may be extracted from a combined analysis of the double beta decay measurements (GERDA, EXO-200 and KamLAND-Zen collaborations) and ATLAS data on the two-jets two-leptons signals following the excitation of a virtual RH boson mediated by a heavy-mass neutrino. In this work we shall compare results of both types of experiments, and show that the estimates are not in tension.

  5. Purifications of calcium carbonate and molybdenum oxide powders for neutrinoless double beta decay experiment, AMoRE

    The AMoRE (Advanced Mo based Rare process Experiment) collaboration is going to use calcium molybdate crystals to search for neutrinoless double beta decay of 100Mo isotope. In order to make the crystal, we use calcium carbonate and molybdenum oxide powders as raw materials. Therefore it is highly necessary to reduce potential sources for radioactive backgrounds such as U and Th in the powders. In this talk, we will present our studies for purification of calcium carbonate and molybdenum oxide powders

  6. CdWO4 scintillating bolometer for Double Beta Decay: Light and Heat anticorrelation, light yield and quenching factors

    Arnaboldi, C.; Beeman, J.W.; Cremonesi, O.; Gironi, L.; M. Pavan; Pessina, G.(Sezione INFN di Milano Bicocca, Milan, Italy); Pirro, S.(INFN-Laboratori Nazionali del Gran Sasso, Assergi, 67010 , L’Aquila, Italy); Previtali, E.

    2010-01-01

    Abstract We report the performances of a 0.51 kg CdWO4 scintillating bolometer to be used for future Double Beta Decay Experiments. The simultaneous read-out of the heat and the scintillation light allows to discriminate between different interacting particles aiming at the disentanglement and the reduction of background contribution, key issue for next generation experiments. We will describe the observed anticorrelation between the heat and the light signal and we will show how t...

  7. The nuclear matrix elements of double beta decay in Pseudo-SU(4) model

    Due to the importance in determining the neutrino mass, the study of the neutrinoless double beta decay (ουββ) has gained much attention in recent years. In the perspective of nuclear structure the focus is the calculation of the nuclear matrix elements (NME) of the relevant nuclei. One way to tackle the problem is to study the NME of the corresponding 2υββ. To this end, various models are explored, i.e. the Interacting Shell Model, the Interacting Boson Model, etc. This work intends to calculate the NME of the 2υββ decay 76Ge→76 Se in the framework of the pseudo-SU(4) x pseudo-SU(6) model, since the concept of pseudo-orbit and pseudo-spin describes well the strong mixing among the p 1/2 -p 3/2 -f 5/2 (or the fds) orbits. The shell model space of the two nuclei is decomposed into fds- and g-subshell. While for the g-subshell the seniority zero restriction applies [4], in the ~ ds subshell the gSU(3) symmetry dominates, which reflects the strong interaction between proton- and neutron-sector. For the nuclei 76Ge and 76Se, the experimental occupation numbers of different orbits provide constraints to the configurations (N N and [M M ] in the g- and the fds-subshell, respectively. In the g-subshell it is reasonable to restrict the configuration to (n1, n2) with n1 = 0, 2 and n2 = 4, 6, 8, respectively for both nuclei. The corresponding configurations in the fds-subshell are [(4-n1), (16-n2)] for 76Ge and [(6-n1), (14-n2)] for 76Se, respectively. Through an algebraic analysis of the gSU(4) x gSU(6) model, taking into account the seniority-zero restriction for g-subshell, the two beta decays happen only either within the g-subshell or in the fds-subshell. Therefore there exist only two types of transition, i.e. (n1, n2) ! ((n1 + 2), (n2 - 2)), or [m1,m2] ! [(m1 + 2), (m2 - 2)]. This feature greatly simplifies the calculation of NME of the 2υββ. The amplitudes of the configurations are determined by fitting the nuclear properties of the two nuclei and then

  8. First results on double beta decay modes of Cd, Te and Zn isotopes with the COBRA experiment

    Bloxham, T; Dawson, J; Dobos, D; Fox, S P; Freer, M; Fulton, B R; Gößling, C; Harrison, P F; Junker, M; Kiel, H; McGrath, J; Morgan, B; Münstermann, D; Nolan, P; Oehl, S; Ramachers, Y; Reeve, C; Stewart, D; Wadsworth, R; Wilson, J R; Zuber, K

    2007-01-01

    Four 1cm^3 CdZnTe semiconductor detectors were operated in the Gran Sasso National Laboratory to explore the feasibility of such devices for double beta decay searches as proposed for the COBRA experiment. The research involved background studies accompanied by measurements of energy resolution performed at the surface. Energy resolutions sufficient to reduce the contribution of two-neutrino double beta decay events to a negligible level for a large scale experiment have already been achieved and further improvements are expected. Using activity measurements of contaminants in all construction materials a background model was developed with the help of Monte Carlo simulations and major background sources were identified. A total exposure of 4.34 kg.days of underground data has been accumulated allowing a search for neutrinoless double beta decay modes of seven isotopes found in CdZnTe. Half-life limits (90% C.L.) are presented for decays to ground and excited states. Four improved lower limits have been obtai...

  9. Results on neutrinoless double beta decay search in GERDA. Background modeling and limit setting

    Becerici Schmidt, Neslihan

    2014-07-22

    The search for the neutrinoless double beta decay (0νββ) process is primarily motivated by its potential of revealing the possible Majorana nature of the neutrino, in which the neutrino is identical to its antiparticle. It has also the potential to yield information on the intrinsic properties of neutrinos, if the underlying mechanism is the exchange of a light Majorana neutrino. The Gerda experiment is searching for 0νββ decay of {sup 76}Ge by operating high purity germanium (HPGe) detectors enriched in the isotope {sup 76}Ge (∝ 87%), directly in ultra-pure liquid argon (LAr). The first phase of physics data taking (Phase I) was completed in 2013 and has yielded 21.6 kg.yr of data. A background index of B∼10{sup -2} cts/(keV.kg.yr) at Q{sub ββ}=2039 keV has been achieved. A comprehensive background model of the Phase I energy spectrum is presented as the major topic of this dissertation. Decomposition of the background energy spectrum into the individual contributions from different processes provides many interesting physics results. The specific activity of {sup 39}Ar has been determined. The obtained result, A=(1.15±0.11) Bq/kg, is in good agreement with the values reported in literature. The contribution from {sup 42}K decays in LAr to the background spectrum has yielded a {sup 42}K({sup 42}Ar) specific activity of A=(106.2{sub -19.2}{sup +12.7}) μBq/kg, for which only upper limits exist in literature. The analysis of high energy events induced by α decays in the {sup 226}Ra chain indicated a total {sup 226}Ra activity of (3.0±0.9) μBq and a total initial {sup 210}Po activity of (0.18±0.01) mBq on the p{sup +} surfaces of the enriched semi-coaxial HPGe detectors. The half life of the two-neutrino double beta (2νββ) decay of {sup 76}Ge has been determined as T{sub 1/2}{sup 2ν}=(1.926±0.094).10{sup 21} yr, which is in good agreement with the result that was obtained with lower exposure and has been published by the Gerda collaboration

  10. Results on neutrinoless double beta decay search in GERDA. Background modeling and limit setting

    The search for the neutrinoless double beta decay (0νββ) process is primarily motivated by its potential of revealing the possible Majorana nature of the neutrino, in which the neutrino is identical to its antiparticle. It has also the potential to yield information on the intrinsic properties of neutrinos, if the underlying mechanism is the exchange of a light Majorana neutrino. The Gerda experiment is searching for 0νββ decay of 76Ge by operating high purity germanium (HPGe) detectors enriched in the isotope 76Ge (∝ 87%), directly in ultra-pure liquid argon (LAr). The first phase of physics data taking (Phase I) was completed in 2013 and has yielded 21.6 kg.yr of data. A background index of B∼10-2 cts/(keV.kg.yr) at Qββ=2039 keV has been achieved. A comprehensive background model of the Phase I energy spectrum is presented as the major topic of this dissertation. Decomposition of the background energy spectrum into the individual contributions from different processes provides many interesting physics results. The specific activity of 39Ar has been determined. The obtained result, A=(1.15±0.11) Bq/kg, is in good agreement with the values reported in literature. The contribution from 42K decays in LAr to the background spectrum has yielded a 42K(42Ar) specific activity of A=(106.2-19.2+12.7) μBq/kg, for which only upper limits exist in literature. The analysis of high energy events induced by α decays in the 226Ra chain indicated a total 226Ra activity of (3.0±0.9) μBq and a total initial 210Po activity of (0.18±0.01) mBq on the p+ surfaces of the enriched semi-coaxial HPGe detectors. The half life of the two-neutrino double beta (2νββ) decay of 76Ge has been determined as T1/22ν=(1.926±0.094).1021 yr, which is in good agreement with the result that was obtained with lower exposure and has been published by the Gerda collaboration. According to the model, the background in Qββ±5 keV window is resulting from close-by decays of 214Bi, 228Th

  11. A search for various double beta decay modes of tin isotopes

    For the first time an extensive search for various double beta decay modes of 124Sn and 112Sn has been performed. A total exposure of 43.29 kg days has been accumulated. New half-life limits of 124Sn into excited states of 124Te have been obtained; the lower half-life limit for the first excited 2+ state at 602.7 keV is T1/2>3.1x1018 yr (90% CL) and for the first excited 0+ state T1/2>7.7x1018 yr (90% CL). For the very first time, ground state and excited state transitions of 112Sn have been experimentally explored. The obtained half-life limits for EC/EC and β+/EC into the first excited 2+ state of 112Cd are both T1/2>1.4x1018 yr (90% CL). A resonance enhancement in the decay rate for 0νEC/EC might be expected for the 0+-state at 1870.9 keV due to degeneracy with the 112Sn ground state. No signal was found resulting in a lower half-life limit of T1/2>1.6x1018 yr (90% CL) for this decay. As all the excited state searches are based on gamma-lines, all half-life limits apply for both neutrino and neutrino-less modes. Neutrinoless ground state transitions were searched for in the EC/EC and β+/EC mode and a limit of T1/2>1.5x1018 yr (90% CL) was obtained for EC/EC decays of 112Sn, whilst the β+/EC mode results are inconclusive

  12. Radon emanation based material measurement and selection for the SuperNEMO double beta experiment

    The SuperNEMO Demonstrator experiment aims to study the neutrinoless double beta decay of 7 kg of 82Se in order to reach a limit on the light Majorana neutrino mass mechanism T1/2 (ββ0ν) > 6.5 1024 years (90%CL) equivalent to a mass sensitivity mββ < 0.20 - 0.40 eV (90%CL) in two years of data taking. The detector construction started in 2014 and its installation in the Laboratoire Souterrain de Modane (LSM) is expected during the course of 2015. The remaining level of 226Ra (238U chain) in the detector components can lead to the emanation of 222Rn gas. This isotope should be controlled and reduced down to the level of a 150 µBq/m3 in the tracker chamber of the detector to achieve the physics goals. Besides the HPGe selection of the detector materials for their radiopurity, the most critical materials have been tested and selected in a dedicated setup facility able to measure their 222Rn emanation level. The operating principle relies on a large emanation tank (0.7m3) that allows measuring large material surfaces or large number of construction pieces. The emanation tank is coupled to an electrostatic detector equipped with a silicon diode to perform the alpha spectroscopy of the gas it contains and extract the 222Rn daughters. The transfer efficiency and the detector efficiency have been carefully calibrated through different methods. The intrinsic background of the system allows one to measure 222Rn activities down to 3 mBq, leading to a typical emanation sensitivity of 20 µBq/m2/day for a 30 m2 surface sample. Several construction materials have been measured and selected, such as nylon and aluminized Mylar films, photomultipliers and tracking of the SuperNEMO Demonstrator

  13. New determination of double-beta-decay properties in 48Ca: high-precision Q-value measurement and improved nuclear matrix element calculations

    Kwiatkowski, A A; Holt, J D; Chaudhuri, A; Chowdhury, U; Eibach, M; Engel, J; Gallant, A T; Grossheim, A; Horoi, M; Lennarz, A; Macdonald, T D; Pearson, M R; Schultz, B E; Simon, M C; Senkov, R A; Simon, V V; Zuber, K; Dilling, J

    2013-01-01

    We report a direct measurement of the Q-value of the neutrinoless double-beta-decay candidate 48Ca at the TITAN Penning-trap mass spectrometer, with the result that Q = 4267.98(32) keV. We measured the masses of both the mother and daughter nuclides, and in the latter case found a 1 keV deviation from the literature value. In addition to the Q-value, we also present results of a new calculation of the neutrinoless double-beta-decay nuclear matrix element of 48Ca. Using diagrammatic many-body perturbation theory to second order to account for physics outside the valence space, we constructed an effective shell-model double-beta-decay operator, which increased the nuclear matrix element by about 75% compared with that produced by the bare operator. The new Q-value and matrix element strengthen the case for a 48Ca double-beta-decay experiment.

  14. Direct mass measurements of cadmium and palladium isotopes and their double-beta transition $Q$-values

    Smorra, C; Blaum, K; Block, M; Düllmann, Ch E; Eberhardt, K; Eibach, M; Eliseev, S; Nagy, Sz; Nörtershäuser, W; Renisch, D

    2012-01-01

    The $Q$-value of the double-electron capture in $^{108}$Cd has been determined to be (272.04 $\\pm$ 0.55) keV in a direct measurement with the double-Penning trap mass spectrometer TRIGA-TRAP. Based on this result a resonant enhancement of the decay rate of $^{108}$Cd is excluded. We have confirmed the double-beta transition $Q$-values of $^{106}$Cd and $^{110}$Pd recently measured with the Penning-trap mass spectrometers SHIPTRAP and ISOLTRAP, respectively. Furthermore, the atomic masses of the involved nuclides ($^{106, 108, 110}$Cd, $^{106, 108, 110}$Pd) have been directly linked to the atomic mass standard.

  15. Efficacy of Carvedilol in Patients with Dilated Cardiomyopathy due to Beta-Thalassemia Major; a Double-Blind Randomized Controlled Trial

    Gholam-Hossein Ajami; Hamid Amoozgar; Mohammad Borzouee; Mehran Karimi; Farah Piravian; Afsaneh Ashrafi; Zahra Kheirandish

    2010-01-01

    Objective: Dilated cardiomyopathy is the end result of chronic iron overload in patients with beta thalassemia major. The objective of the present study was to evaluate the safety and efficacy of Carvedilol in patients with beta thalassemia major and dilated cardiomyopathy.Methods: During a six-month period, fourteen patients with beta-thalassemia major and heart failure without diabetes mellitus referred to pediatric cardiology clinic enrolled in this double blind, randomly assigned study. A...

  16. Spatial Double Generalized Beta Regression Models: Extensions and Application to Study Quality of Education in Colombia

    Cepeda-Cuervo, Edilberto; Núñez-Antón, Vicente

    2013-01-01

    In this article, a proposed Bayesian extension of the generalized beta spatial regression models is applied to the analysis of the quality of education in Colombia. We briefly revise the beta distribution and describe the joint modeling approach for the mean and dispersion parameters in the spatial regression models' setting. Finally, we…

  17. CALDER - Neutrinoless double-beta decay identification in TeO$_2$ bolometers with kinetic inductance detectors

    Battistelli, E S; Calvo, M; Cardani, L; Casali, N; Castellano, M G; Colantoni, I; Coppolecchia, A; Cosmelli, C; Cruciani, A; de Bernardis, P; Di Domizio, S; D'Addabbo, A; Martinez, M; Masi, S; Pagnanini, L; Tomei, C; Vignati, M

    2015-01-01

    Next-generation experiments searching for neutrinoless double-beta decay must be sensitive to a Majorana neutrino mass as low as 10 meV. CUORE, an array of 988 TeO$_2$ bolometers being commissioned at Laboratori Nazionali del Gran Sasso in Italy, features an expected sensitivity of 50-130 meV at 90% C.L, that can be improved by removing the background from $\\alpha$ radioactivity. This is possible if, in coincidence with the heat release in a bolometer, the Cherenkov light emitted by the $\\beta$ signal is detected. The amount of light detected is so far limited to only 100 eV, requiring low-noise cryogenic light detectors. The CALDER project (Cryogenic wide-Area Light Detectors with Excellent Resolution) aims at developing a small prototype experiment consisting of TeO$_2$ bolometers coupled to new light detectors based on kinetic inductance detectors. The R&D is focused on the light detectors that could be implemented in a next-generation neutrinoless double-beta decay experiment.

  18. Background discrimination in neutrinoless double beta decay search with $\\textrm{TeO}_{2}$ bolometers using Neganov-Luke amplified cryogenic light detectors

    Willers, M; Giuliani, A; Gütlein, A; Münster, A; Lanfranchi, J -C; Oberauer, L; Potzel, W; Roth, S; Schönert, S; Sivers, M v; Wawoczny, S; Zöller, A

    2014-01-01

    We demonstrate that Neganov-Luke amplified cryogenic light detectors with Transition Edge Sensor read-out can be applied for the background suppression in cryogenic experiments searching for the neutrinoless double beta decay of $^{130}\\text{Te}$ with $\\text{TeO}_{2}$ based bolometers. Electron and gamma induced events can be discriminated from $\\alpha$ events by detecting the Cherenkov light produced by the $\\beta$ particles emitted in the decay. We use the Cherenkov light produced by events in the full energy peak of $^{208}\\text{Tl}$ and by events from a $^{147}\\text{Sm}$ source to show that at the Q-value of the neutrinoless double beta decay of $^{130}\\text{Te}$ ($Q_{\\beta \\beta} = 2.53 \\,\\text{MeV}$), a separation of $e^{-}/\\gamma$ events from $\\alpha$ events can be achieved on an event-by-event basis with practically no reduction in signal acceptance.

  19. The Heidelberg-Moscow double beta decay experiment with enriched sup 76 Ge. First result

    Balysh, A.; Belyaev, S.T.; Demehin, A.; Gurov, A.; Kondratenko, I.; Lebedev, V.I. (Max-Planck-Inst. fuer Kernphysik, Heidelberg (Germany)); Beck, M.; Bockholt, J.; Echternach, J.; Heusser, G.; Hirsch, M.; Klapdor-Kleingrothaus, H.V.; Maier, B.; Petry, F.; Piepke, A.; Schmidt-Rohr, U.; Strecker, H.; Zuber, K. (Kurchatov Inst., Moscow (USSR)); Mueller, A. (Ist. Nazionale di Fisica Nucleare, Assergi (Italy))

    1992-06-04

    The status of the Heidelberg-Moscow {beta}{beta}-experiment using isotopically enriched {sup 76}Ge is reported. The results of 14.8 mol yr (or 1.29 kg yr) of operation are presented. From these data a new half life time for the {beta}{beta}0{nu}-decay of {sup 76}Ge to the ground state of {sup 76}Se of T{sub 1/2}>1.4(2.5)x10{sup 24} yr with 90% (68%) CL can be deduced. For a possible neutrinoless decay to the first excited state a half life of 4.3(8.2)x10{sup 23} yr can be excluded with 90% (68%) CL. (orig.).

  20. Search for Majoron-emitting modes of double-beta decay of $^{136}$Xe with EXO-200

    :,; Auty, D J; Barbeau, P S; Beauchamp, E; Beck, D; Belov, V; Benitez-Medina, C; Breidenbach, M; Brunner, T; Burenkov, A; Cao, G F; Chambers, C; Chaves, J; Cleveland, B; Coon, M; Craycraft, A; Daniels, T; Danilov, M; Daugherty, S J; Davis, C G; Davis, J; DeVoe, R; Delaquis, S; Didberidze, T; Dolgolenko, A; Dolinski, M J; Dunford, M; Fairbank, W; Farine, J; Feldmeier, W; Fierlinger, P; Fudenberg, D; Giroux, G; Gornea, R; Graham, K; Gratta, G; Hall, C; Herrin, S; Hughes, M; Jewell, M J; Jiang, X S; Johnson, A; Johnson, T N; Johnston, S; Karelin, A; Kaufman, L J; Killick, R; Koffas, T; Kravitz, S; Kuchenkov, A; Kumar, K S; Leonard, D S; Leonard, F; Licciardi, C; Lin, Y H; Ling, J; MacLellan, R; Marino, M G; Mong, B; Moore, D; Nelson, R; Odian, A; Ostrovskiy, I; Ouellet, C; Piepke, A; Pocar, A; Prescott, C Y; Rivas, A; Rowson, P C; Rozo, M P; Russell, J J; Schubert, A; Sinclair, D; Smith, E; Stekhanov, V; Tarka, M; Tolba, T; Tosi, D; Tsang, R; Twelker, K; Vogel, P; Vuilleumier, J -L; Waite, A; Walton, J; Walton, T; Weber, M; Wen, L J; Wichoski, U; Yang, L; Yen, Y -R; Zeldovich, O Ya

    2014-01-01

    EXO-200 is a single phase liquid xenon detector designed to search for neutrinoless double-beta decay of $^{136}$Xe. Here we report on a search for various Majoron-emitting modes based on 100 kg$\\cdot$yr exposure of $^{136}$Xe. A lower limit of $T^{^{136}Xe}_{1/2} >1.2...10^{24}$ yr at 90% C.L. on the half-life of the spectral index = 1 Majoron decay was obtained, corresponding to a constraint on the Majoron-neutrino coupling constant of $||<$ (0.8-1.7)...10$^{-5}$.

  1. Explaining the CMS $eejj$ Excess With $\\mathcal{R}-$parity Violating Supersymmetry and Implications for Neutrinoless Double Beta Decay

    Allanach, Ben; Mondal, Subhadeep; Mitra, Manimala

    2014-01-01

    The recent CMS searches for the right handed gauge boson $W_R$ reports an interesting deviation from the Standard Model. The search has been conducted in the $eejj$ channel and has shown an excess around $m_{eejj} \\sim 2$ TeV. In this work, we explain the reported CMS excess with R-parity violating supersymmetry (SUSY). We consider the resonant slepton and sneutrino production, followed by the three body decays of neutralino and chargino via R-parity violating coupling. These fit the excess for slepton and sneutrino masses around 2 TeV. This scenario can further be tested in neutrinoless double beta decay experiment ($0\

  2. The Potential of Hybrid Pixel Detectors in the Search for the Neutrinoless Double-Beta Decay of 116Cd

    Mykhaylo Filipenko; Stefan Geißelsöder; Jürgen Durst; Thomas Gleixner; Thilo Michel

    2013-01-01

    We investigated the potential of the energy resolving hybrid pixel detector Timepix contacted to a CdTe sensor layer for the search for the neutrinoless double-beta decay of Cd. We found that a CdTe sensor layer with 3 mm thickness and 165 μm pixel pitch is optimal with respect to the effective Majorana neutrino mass (mββ) sensitivity. In simulations, we were able to demonstrate a possible reduction of the background level caused by single electrons by approximately 75% at a specific backgrou...

  3. Cryogen-free dilution refrigerator for bolometric search of neutrinoless double beta decay (0 ) in 124Sn

    V Singh; S Mathimalar; N Dokania; V Nanal; R G Pillay; S Ramakrishnan

    2013-10-01

    The feasibility study for searching neutrinoless double beta decay in 124Sn using cryogenic bolometer has been initiated. For this purpose, a custom-built cryogen-free dilution refrigerator, having a large cooling power of 1.4 mW at 120 mK, has been installed at TIFR, India. This paper describes the design, installation and performance of a cryogen-free dilution refrigerator (CFDR-1200). The performance of CFDR-1200 has been analysed using Takano’s model developed for conventional (wet) dilution refrigerators.

  4. Technique for 136Xe double beta decay search by means of wall-less high pressure proportional counters

    The methodology of the experiment for search of the double beta-decay of the 136Xe isotope through the multiple thread wall-less proportional high-pressure counters is described. The characteristics of the counters and low-background facility are presented. The methodology for decreasing the counters background in the 0.5-3.5 MeV energies area through discrimination events by a coordinate along the anode thread and by the pulses growth-time is considered. The results of the background components analysis by the events type and source position are presented

  5. SDSS J083253.18+064316.7: one strange object with double-peaked narrow H\\alpha but single-peaked narrow H\\beta

    Zhang, XueGuang

    2015-01-01

    In this letter, we firstly report one unique object SDSS J0832+0643 with particular features of narrow balmer emission lines: double-peaked narrow H\\alpha but single-peaked narrow H\\beta. The particular features can not be expected by currently proposed kinematic models for double-peaked narrow emission lines, because the proposed kinematic models lead to similar line profiles of narrow balmer emission lines. However, due to radiative transfer effects, the non-kinematic model can be naturally applied to well explain the particular features of narrow balmer emission lines: larger optical depth in H\\alpha than 10 leads to observed double-peaked narrow H\\alpha, but smaller optical depth in H\\beta around 2 leads to observed single-peaked narrow H\\beta. Therefore, SDSS J0832+0643 can be used as strong evidence to support the non-kinematic model for double-peaked narrow emission lines.

  6. New Half-life Limits on Double Beta Decays of Pd110 and Pd102 into Excited States

    Lehnert, Bjoern; Andreotti, Erica; Hult, Mikael

    2012-01-01

    A search for excited state transitions of double beta decay in Pd110 and double electron capture in Pd102 has been performed in the HADES underground laboratory with two low background HPGe detectors in sandwich configuration. After an exposure of 35.92 kg*d, no signal was found. The frequentist spectral analysis resulted in lower half-life limits of 1.98e20 yr and 1.72e20 yr (95% CL) for the first 0+ and 2+ excited state in Pd110 respectively. This is an improvement by more than a factor of 3 with respect to previous measurements. In Pd102, the lower half-life limit could be improved to 5.95e18 yr (95% CL) for the first 0+ excited state. Furthermore, first experimental lower half-live limits are found for all possible excited states in the Pd110 and Pd102 systems.

  7. Dilepton bounds on left-right symmetry at the LHC run II and neutrinoless double beta decay

    Lindner, Manfred; Rodejohann, Werner

    2016-01-01

    In the light of the new 13 TeV dilepton data set with $ 3.2\\, {\\rm fb^{-1}}$ integrated luminosity from the ATLAS collaboration, we derive limits on the $Z^{\\prime}$ mass in the context of left-right symmetric models and exploit the complementarity with dijet and $lljj$ data, as well as neutrinoless double beta decay. We keep the ratio of the left- and right-handed gauge coupling free in order to take into account different patterns of left-right symmetry breaking. By combining the dielectron and dimuon data we can exclude $Z^{\\prime}$ masses below $3$~TeV for $g_R=g_L$, and for $g_R \\sim 1$ we rule out masses up to $\\sim 4$~TeV. Those comprise the strongest direct bounds on the $Z^{\\prime}$ mass from left-right models up to date. We show that in the usual plane of right-handed neutrino and charged gauge boson mass, dilepton data can probe a region of parameter space inaccessible to neutrinoless double beta decay and $lljj$ studies. Lastly, we present a stringent indirect indirect bound on the lifetime of neu...

  8. Two-neutrino double-beta decay of $^{150}$Nd to excited final states in $^{150}$Sm

    Kidd, Mary F; Finch, Sean W; Tornow, Werner

    2014-01-01

    Double-beta decay is a rare nuclear process in which two neutrons in the nucleus are converted to two protons with the emission of two electrons and two electron anti-neutrinos. We measured the half life of the two-neutrino double-beta decay of $^{150}$Nd to excited final states of $^{150}$Sm by detecting the de-excitation gamma rays of the daughter nucleus. This study yields the first detection of the coincidence gamma rays from the 0$^+_1$ excited state of $^{150}$Sm. These gamma rays have energies of 333.97 keV and 406.52 keV, and are emitted in coincidence through a 0$^+_1\\rightarrow$2$^+_1\\rightarrow$0$^+_{gs}$ transition. The enriched Nd$_2$O$_3$ sample consisted of 40.13 g $^{150}$Nd and was observed for 642.8 days at the Kimballton Underground Research Facility, producing 21.6 net events in the region of interest. This count rate gives a half life of $T_{1/2}=(1.07^{+0.45}_{-0.25}(stat)\\pm0.07(syst.))\\times 10^{20}$ years. The effective nuclear matrix element was found to be 0.0465$^{+0.0098}_{-0.0054...

  9. Pattern recognition of 136Xe double beta decay events and background discrimination in a high pressure xenon TPC

    High pressure xenon gas time projection chambers (TPC) for the detection of the neutrinoless double beta decay of 136Xe provide good energy resolution and detailed topological information of events. The ionization topology of the double beta decay event of 136Xe in gaseous xenon has a characteristic shape defined by the two straggling electron tracks ending in two larger energy depositions. With a properly pixelized readout, this topological information is invaluable for performing powerful background discrimination. In this study, we carry out detailed simulations of the signal topology, as well as of the competing topologies from gamma events that typically compose the background at these energies. We define observables based on graph theory concepts and develop automated discrimination algorithms which reduce the background level in the region of interest by around three orders of magnitude, while keeping signal efficiency of 40%. This result supports the competitiveness of current or future ββ experiments based on gas TPCs, such as the Neutrino Xenon TPC (NEXT) currently under construction at the Laboratorio Subterráneo de Canfranc. (paper)

  10. The Majorana Demonstrator: Progress towards showing the feasibility of a 76Ge neutrinoless double-beta decay experiment

    Finnerty, P.; Aguayo, Estanislao; Amman, M.; Avignone, Frank T.; Barabash, Alexander S.; Barton, P. J.; Beene, Jim; Bertrand, F.; Boswell, M.; Brudanin, V.; Busch, Matthew; Chan, Yuen-Dat; Christofferson, Cabot-Ann; Collar, J. I.; Combs, Dustin C.; Cooper, R. J.; Detwiler, Jason A.; Doe, P. J.; Efremenko, Yuri; Egorov, Viatcheslav; Ejiri, H.; Elliott, S. R.; Esterline, James H.; Fast, James E.; Fields, N.; Fraenkle, Florian; Galindo-Uribarri, A.; Gehman, Victor M.; Giovanetti, G. K.; Green, M.; Guiseppe, Vincente; Gusey, K.; Hallin, A. L.; Hazama, R.; Henning, Reyco; Hoppe, Eric W.; Horton, Mark; Howard, Stanley; Howe, M. A.; Johnson, R. A.; Keeter, K.; Kidd, M. F.; Knecht, A.; Kochetov, Oleg; Konovalov, S.; Kouzes, Richard T.; LaFerriere, Brian D.; Leon, Jonathan D.; Leviner, L.; Loach, J. C.; Looker, Q.; Luke, P.; MacMullin, S.; Marino, Michael G.; Martin, R. D.; Merriman, Jason H.; Miller, M. L.; Mizouni, Leila; Nomachi, Masaharu; Orrell, John L.; Overman, Nicole R.; Perumpilly, Gopakumar; Phillips, David; Poon, Alan; Radford, D. C.; Rielage, Keith; Robertson, R. G. H.; Ronquest, M. C.; Schubert, Alexis G.; Shima, T.; Shirchenko, M.; Snavely, Kyle J.; Steele, David; Strain, J.; Timkin, V.; Tornow, Werner; Varner, R. L.; Vetter, Kai; Vorren, Kris R.; Wilkerson, J. F.; Yakushev, E.; Yaver, Harold; Young, A.; Yu, Chang-Hong; Yumatov, Vladimir

    2014-03-24

    The Majorana Demonstrator will search for the neutrinoless double-beta decay (0*) of the 76Ge isotope with a mixed array of enriched and natural germanium detectors. The observation of this rare decay would indicate the neutrino is its own anti-particle, demonstrate that lepton number is not conserved, and provide information on the absolute mass-scale of the neutrino. The Demonstrator is being assembled at the 4850 foot level of the Sanford Underground Research Facility in Lead, South Dakota. The array will be contained in a lowbackground environment and surrounded by passive and active shielding. The goals for the Demonstrator are: demonstrating a background rate less than 3 counts tonne -1 year-1 in the 4 keV region of interest (ROI) surrounding the 2039 keV 76Ge endpoint energy; establishing the technology required to build a tonne-scale germanium based double-beta decay experiment; testing the recent claim of observation of 0; and performing a direct search for lightWIMPs (3-10 GeV/c2).

  11. Measurement of the half-life of the two-neutrino double beta decay of Ge-76 with the Gerda experiment

    Agostini, M; Andreotti, E; Bakalyarov, A M; Balata, M; Barabanov, I; Heider, M Barnabe; Barros, N; Baudis, L; Bauer, C; Becerici-Schmidt, N; Bellotti, E; Belogurov, S; Belyaev, S T; Benato, G; Bettini, A; Bezrukov, L; Bode, T; Brudanin, V; Brugnera, R; Budjas, D; Caldwell, A; Cattadori, C; Chernogorov, A; Cossavella, F; Demidova, E V; Denisov, A; Domula, A; Egorov, V; Falkenstein, R; Ferella, A D; Freund, K; Froborg, F; Frodyma, N; Gangapshev, A; Garfagnini, A; Gazzana, S; Grambayr, P; Gurentsov, V; Gusev, K; Guthikonda, K K; Hampel, W; Hegai, A; Heisel, M; Hemmer, S; Heusser, G; Hofmann, W; Hult, M; Inzhechik, L V; Ioannucci, L; Csathy, J Janicsko; Jochum, J; Junker, M; Kianovsky, S; Kirpichnikov, I V; Kirsch, A; Klimenko, A; Knoepfle, K T; Kochetov, O; Kornoukhov, V N; Kusminov, V; Laubenstein, M; Lazzaro, A; Lebedev, V I; Lehnert, B; Liao, H Y; Lindner, M; Lippi, I; Liu, X; Lubashevskiy, A; Lubsandorzhiev, B; Lutter, G; Machado, A A; Majorovits, B; Maneschg, W; Nemchenok, I; Nisi, S; O'Shaughnessy, C; Pandola, L; Pelczar, K; Peraro, L; Pullia, A; Riboldi, S; Ritter, F; Sada, C; Salathe, M; Schmitt, C; Schoenert, S; Schreiner, J; Schulz, O; Schwingenheuer, B; Shevchik, E; Shirchenko, M; Simgen, H; Smolnikov, A; Stanco, L; Strecker, H; Tarka, M; Ur, C A; Vasenko, A A; Volynets, O; von Sturm, K; Walter, M; Wegmann, A; Wojcik, M; Yanovich, E; Zavarise, P; Zhitnikov, I; Zhukov, S V; Zinatulina, D; Zuber, K; Zuzel, G

    2012-01-01

    The primary goal of the GERmanium Detector Array (Gerda) experiment at the Laboratori Nazionali del Gran Sasso of INFN is the search for the neutrinoless double beta decay of Ge-76. High-purity germanium detectors made from material enriched in Ge-76 are operated directly immersed in liquid argon, allowing for a substantial reduction of the background with respect to predecessor experiments. The first 5.04 kg yr of data collected in Phase I of the experiment have been analyzed to measure the half-life of the neutrino-accompanied double beta decay of Ge-76. The observed spectrum in the energy range between 600 and 1800 keV is dominated by the double beta decay of Ge-76. The half-life extracted from Gerda data is T(1/2) = (1.84 +0.14 -0.10) 10^{21} yr.

  12. Measurement of the half-life of the two-neutrino double beta decay of 76Ge with the GERDA experiment

    The GERDA Collaboration; Agostini, M.; Allardt, M.; Andreotti, E.; Bakalyarov, A. M.; Balata, M.; Barabanov, I.; Barnabé Heider, M.; Barros, N.; Baudis, L.; Bauer, C.; Becerici-Schmidt, N.; Bellotti, E.; Belogurov, S.; Belyaev, S. T.; Benato, G.; Bettini, A.; Bezrukov, L.; Bode, T.; Brudanin, V.; Brugnera, R.; Budjáš, D.; Caldwell, A.; Cattadori, C.; Chernogorov, A.; Cossavella, F.; Demidova, E. V.; Denisov, A.; Domula, A.; Egorov, V.; Falkenstein, R.; Ferella, A. D.; Freund, K.; Froborg, F.; Frodyma, N.; Gangapshev, A.; Garfagnini, A.; Gazzana, S.; Grabmayr, P.; Gurentsov, V.; Gusev, K.; Guthikonda, K. K.; Hampel, W.; Hegai, A.; Heisel, M.; Hemmer, S.; Heusser, G.; Hofmann, W.; Hult, M.; Inzhechik, L. V.; Ioannucci, L.; Janicskó Csáthy, J.; Jochum, J.; Junker, M.; Kianovsky, S.; Kirpichnikov, I. V.; Kirsch, A.; Klimenko, A.; Knöpfle, K. T.; Kochetov, O.; Kornoukhov, V. N.; Kuzminov, V.; Laubenstein, M.; Lazzaro, A.; Lebedev, V. I.; Lehnert, B.; Liao, H. Y.; Lindner, M.; Lippi, I.; Liu, X.; Lubashevskiy, A.; Lubsandorzhiev, B.; Lutter, G.; Machado, A. A.; Majorovits, B.; Maneschg, W.; Nemchenok, I.; Nisi, S.; O'Shaughnessy, C.; Pandola, L.; Pelczar, K.; Peraro, L.; Pullia, A.; Riboldi, S.; Ritter, F.; Sada, C.; Salathe, M.; Schmitt, C.; Schönert, S.; Schreiner, J.; Schulz, O.; Schwingenheuer, B.; Shevchik, E.; Shirchenko, M.; Simgen, H.; Smolnikov, A.; Stanco, L.; Strecker, H.; Tarka, M.; Ur, C. A.; Vasenko, A. A.; Volynets, O.; von Sturm, K.; Walter, M.; Wegmann, A.; Wojcik, M.; Yanovich, E.; Zavarise, P.; Zhitnikov, I.; Zhukov, S. V.; Zinatulina, D.; Zuber, K.; Zuzel, G.

    2013-03-01

    The primary goal of the GERmanium Detector Array (GERDA) experiment at the Laboratori Nazionali del Gran Sasso of INFN is the search for the neutrinoless double beta decay of 76Ge. High-purity germanium detectors made from material enriched in 76Ge are operated directly immersed in liquid argon, allowing for a substantial reduction of the background with respect to predecessor experiments. The first 5.04 kg yr of data collected in Phase I of the experiment have been analyzed to measure the half-life of the neutrino-accompanied double beta decay of 76Ge. The observed spectrum in the energy range between 600 and 1800 keV is dominated by the double beta decay of 76Ge. The half-life extracted from GERDA data is T2ν1/2 = (1.84+0.14-0.10) × 1021 yr.

  13. Measurement of scintillation and ionization yield with high-pressure gaseous mixtures of Xe and TMA for improved neutrinoless double beta decay and dark matter searches

    Nakajima, Y; Matis, H S; Nygren, D; Oliveira, C; Renner, J

    2015-01-01

    Liquid Xe TPCs are among the most popular choices for double beta decay and WIMP dark matter searches. Gaseous Xe has intrinsic advantages when compared to Liquid Xe, specifically, tracking capability and better energy resolution for double beta decay searches. The performance of gaseous Xe can be further improved by molecular additives such as trimethylamine(TMA), which are expected to (1) cool down the ionization electrons, (2) convert Xe excitation energy to TMA ionizations through Penning transfer, and (3) produce scintillation and electroluminescence light in a more easily detectable wavelength (300 nm). These features may provide better tracking and energy resolution for double-beta decay searches. They are also expected to enhance columnar recombination for nuclear recoils, which can be used for searches for WIMP dark matter with directional sensitivity. We constructed a test ionization chamber and successfully measured scintillation and ionization yields at high precision with various Xe and TMA mixtu...

  14. Study of the double beta decay of 70≤A≤100 nuclei within the RQRPA and the self-consistent BCS + RQRPA formalisms

    We have used a newly presented self-consistent version of the BCS+RQRPA method for a nucleus-by-nucleus study of the double beta decay in the medium-heavy region. The results have been compared to the previously used approaches, namely the QRPA and the RQRPA approximations. We have shown that inclusion of the quasiparticle correlations at the BCS level reduces ground state correlations in the particle-particle channel of the proton-neutron interaction, resulting in the systematic reduction of the double beta decay matrix elements

  15. Low-background multidetector spectrometer TGV-2 for investigation of double beta decay

    The low-background highly sensitive multidetector spectrometer TGV-2 (germanium vertical telescope) is created for studying very rare nuclear processes such as the double β-decay and double electron capture. The spectrometer consists basically of 32 planar HPGe-detectors with the sensitive volume of approximately 2040 mm2 x 6 mm each, assembled vertically one over another in the ultralow-background U-shape cryostat. The description of the spectrometer design, its basic characteristics and preliminary results of the phase measurements are presented

  16. Development of low background CdZnTe detectors for detection of double beta decays of sup 6 sup 4 Zn

    Watanabe, T; Takahisa, K; Tanikawa, M; Ito, Y

    1999-01-01

    Development of low background CdZnTe detectors is in progress to study neutrino-less double beta decay. The mu tau product (mobility times lifetime) for holes was measured in a set of CdZnTe detectors at various temperatures between +22 deg. C and -40 deg. C in order to investigate charge collection efficiencies for holes. The sensitivity of CdZnTe detectors to neutrino-less beta sup + EC decays of sup 6 sup 4 Zn ( sup 6 sup 4 Zn+EC-> sup 6 sup 4 Ni+beta sup +) is estimated from these data.

  17. Signal modeling of high-purity Ge detectors with a small read-out electrode and application to neutrinoless double beta decay search in Ge-76

    The GERDA experiment searches for the neutrinoless double beta decay of 76Ge using high-purity germanium detectors enriched in 76Ge. The analysis of the signal time structure provides a powerful tool to identify neutrinoless double beta decay events and to discriminate them from gamma-ray induced backgrounds. Enhanced pulse shape discrimination capabilities of Broad Energy Germanium detectors with a small read-out electrode have been recently reported. This paper describes the full simulation of the response of such a detector, including the Monte Carlo modeling of radiation interaction and subsequent signal shape calculation. A pulse shape discrimination method based on the ratio between the maximum current signal amplitude and the event energy applied to the simulated data shows quantitative agreement with the experimental data acquired with calibration sources. The simulation has been used to study the survival probabilities of the decays which occur inside the detector volume and are difficult to assess experimentally. Such internal decay events are produced by the cosmogenic radio-isotopes 68Ge and 60Co and the neutrinoless double beta decay of 76Ge. Fixing the experimental acceptance of the double escape peak of the 2.614 MeV photon to 90%, the estimated survival probabilities at Qββ = 2.039 MeV are (86±3)% for 76Ge neutrinoless double beta decays, (4.5±0.3)% for the 68Ge daughter 68Ga, and (0.9+0.4-0.2)% for 60Co decays.

  18. First test of an enriched $^{116}$CdWO$_4$ scintillating bolometer for neutrinoless double-beta-decay searches

    Danevich, F A; Giuliani, A; Konovalov, S I; Mancuso, M; de Marcillac, P; Marnieros, S; Novati, V; Pessina, G; Poda, D V; Polischuk, O G; Shlegel, V N; Tretyak, V I; Umatov, V I; Zolotarova, A S

    2016-01-01

    For the first time, a cadmium tungstate crystal scintillator enriched in $^{116}$Cd has been succesfully tested as a scintillating bolometer. The measurement was performed above ground at a temperature of 18 mK. The crystal mass was 34.5 g and the enrichment level ~82 %. Despite a substantial pile-up effect due to above-ground operation, the detector demonstrated a high energy resolution (2-7 keV FWHM in 0.2-2.6 MeV $\\gamma$ energy range), a powerful particle identification capability and a high level of internal radiopurity. These results prove that cadmium tungstate is an extremely promising detector material for a next-generation neutrinoless double-beta decay bolometric experiment, like that proposed in the CUPID project (CUORE Upgrade with Particle IDentification).

  19. Radiative Corrections to Light Neutrino Masses in Low Scale Type I Seesaw Scenarios and Neutrinoless Double Beta Decay

    Lopez-Pavon, J; Petcov, S T

    2015-01-01

    We perform a detailed analysis of the one-loop corrections to the light neutrino mass matrix within low scale type I seesaw extensions of the Standard Model and their implications in experimental searches for neutrinoless double beta decay. We show that a sizable contribution to the effective Majorana neutrino mass from the exchange of heavy Majorana neutrinos is always possible, provided one requires a fine-tuned cancellation between the tree-level and one-loop contribution to the light neutrino masses. We quantify the level of fine-tuning as a function of the seesaw parameters and introduce a generalisation of the Casas-Ibarra parametrization of the neutrino Yukawa matrix, which easily allows to include the one-loop corrections to the light neutrino masses.

  20. Two neutrino double $\\beta$ decay of 94v$\\leq A\\leq $110 nuclei for $0^+ \\to 0^+$ transition

    Chandra, R; Rath, P K; Raina, P K; Hirsch, J G

    2005-01-01

    The two neutrino double beta decay of $ ^{94,96}$Zr$,^{98,100}$Mo$,^{104}$% Ru and $ ^{110}$Pd nuclei for $0^{+}\\to 0^{+}$ transition is studied in the PHFB model in conjunction with the summation method. In the first step, the reliability of the intrinsic wave functions has been established by obtaining an overall agreement between a number of theoretically calculated spectroscopic properties and the available experimental data for $ ^{94,96}$% Zr$,^{94,96,98,100}$Mo, $^{98,100,104}$Ru, $^{104,110}$Pd and $^{110}$Cd isotopes. Subsequently, the PHFB wave functions of the above mentioned nuclei are employed to calculate the nuclear transition matrix elements $M_{2\