Combining and comparing neutrinoless double beta decay experiments using different nuclei

Science.gov (United States)

Bergström, Johannes

2013-02-01

We perform a global fit of the most relevant neutrinoless double beta decay experiments within the standard model with massive Majorana neutrinos. Using Bayesian inference makes it possible to take into account the theoretical uncertainties on the nuclear matrix elements in a fully consistent way. First, we analyze the data used to claim the observation of neutrinoless double beta decay in 76Ge, and find strong evidence (according to Jeffrey's scale) for a peak in the spectrum and moderate evidence for that the peak is actually close to the energy expected for the neutrinoless decay. We also find a significantly larger statistical error than the original analysis, which we include in the comparison with other data. Then, we statistically test the consistency between this claim with that of recent measurements using 136Xe. We find that the two data sets are about 40 to 80 times more probable under the assumption that they are inconsistent, depending on the nuclear matrix element uncertainties and the prior on the smallest neutrino mass. Hence, there is moderate to strong evidence of incompatibility, and for equal prior probabilities the posterior probability of compatibility is between 1.3% and 2.5%. If one, despite such evidence for incompatibility, combines the two data sets, we find that the total evidence of neutrinoless double beta decay is negligible. If one ignores the claim, there is weak evidence against the existence of the decay. We also perform approximate frequentist tests of compatibility for fixed ratios of the nuclear matrix elements, as well as of the no signal hypothesis. Generalization to other sets of experiments as well as other mechanisms mediating the decay is possible.

Relativistic pn-QRPA to the double beta decay

International Nuclear Information System (INIS)

Conti, Claudio de; Krmpotic, Francisco; Carlson, Brett Vern

2011-01-01

Full text: In nature there are about 50 nuclear systems where the single beta-decay is energetically forbidden, and double-beta decay turns out to be only possible mode of disintegration. It is the nuclear pairing force which causes such an 'anomaly', by making the mass of the odd-odd isobar, (N - 1;Z + 1), to be greater than the masses of its even-even neighbors, (N;Z) and (N - 2;Z +2). The modes by which the double-beta decay can take place are connected with the neutrino and antineutrino distinction. In case the lepton number is strictly conserved the neutrino is a Dirac fermion and the two-neutrino mode is the only possible mode of disintegration. On the other hand, if this conservation is violated, the neutrino is a Majorana particle and neutrinoless double-beta decay also can occur. Both two-neutrino and neutrinoless double-beta decay processes have attracted much attention, because a comparison between experiment and theory for the first, provides a measure of confidence one may have in the nuclear wave function employed for extracting the unknown parameters from neutrinoless lifetime measurements. The proton-neutron (pn) quasiparticle random phase approximation (QRPA) has turned out be the most simple model for calculating the nuclear wave function involved in the double-beta decay transitions. In this work the transition matrix elements for 0 + → 0 + double-beta decay are calculated for 48 Ca, 76 Ge, 82 Se, 100 Mo, 128 Te and 130 Te nuclei, using a relativistic pn-QRPA based on Hartree-Bogoliubov approximation to the single-particle motion. (author)

The MAJORANA experiment: an ultra-low background search for neutrinoless double-beta decay

Energy Technology Data Exchange (ETDEWEB)

Phillips, D.; Aguayo Navarrete, Estanislao; Avignone, Frank T.; Back, Henning O.; Barabash, Alexander S.; Bergevin, M.; 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, Peter J.; Efremenko, Yuri; Egorov, Viatcheslav; Ejiri, H.; Elliott, Steven R.; Esterline, James H.; Fast, James E.; Fields, N.; Finnerty, P.; Fraenkle, Florian; Gehman, Victor; Giovanetti, G. K.; Green, Matthew P.; Guiseppe, Vincente; Gusey, K.; Hallin, A. L.; Hazama, R.; Henning, Reyco; Hime, Andrew; Hoppe, Eric W.; Horton, Mark; Howard, Stanley; Howe, M. A.; Johnson, R. A.; Keeter, K.; Keller, C.; Kidd, Mary; Knecht, A.; Kochetov, Oleg; Konovalov, S.; Kouzes, Richard T.; LaFerriere, Brian D.; LaRoque, B. H.; Leon, Jonathan D.; Leviner, L.; Loach, J. C.; MacMullin, S.; Marino, Michael G.; Martin, R. D.; Mei, Dong-Ming; Merriman, Jason H.; Miller, M. L.; Mizouni, Leila; Nomachi, Masaharu; Orrell, John L.; Overman, Nicole R.; Poon, Alan; Perumpilly, Gopakumar; Prior, Gersende; 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.; Thomas, K.; Timkin, V.; Tornow, W.; Vanyushin, I.; Varner, R. L.; Vetter, Kai; Vorren, Kris R.; Wilkerson, J. F.; Wolfe, B. A.; Yakushev, E.; Young, A.; Yu, Chang-Hong; Yumatov, Vladimir; Zhang, C.

2012-12-01

The observation of neutrinoless double-beta decay would resolve the Majorana nature of the neutrino and could provide information on the absolute scale of the neutrino mass. The initial phase of the Majorana Experiment, known as the Demonstrator, will house 40 kg of Ge in an ultra-low background shielded environment at the 4850' level of the Sanford Underground Laboratory in Lead, SD. The objective of the Demonstrator is to validate whether a future 1-tonne experiment can achieve a background goal of one count per tonne-year in a narrow region of interest around the 76Ge neutrinoless double-beta decay peak.

The SNO+ experiment for neutrinoless double-beta decay

Energy Technology Data Exchange (ETDEWEB)

Lozza, Valentina; Krosigk, Belina von; Soerensen, Arnd; Zuber, Kai [Institut fuer Kern- und Teilchenphysik, Dresden (Germany)

2015-07-01

SNO+ is a large liquid scintillator based experiment that re-uses the Sudbury Neutrino Observatory detector. The detector, located 2 km underground in a mine near Sudbury, Canada, consists of a 12 m diameter acrylic vessel which will be filled with 780 tonnes of liquid scintillator. The main physics goal of SNO+ is to search for the neutrinoless double-beta (0n2b) decay of {sup 130}Te. During the double-beta phase, the liquid scintillator will be initially loaded with 0.3% natural tellurium (nearly 800 kg of {sup 130}Te). During this demonstration phase we anticipate that we will achieve a sensitivity in the region just above the inverted neutrino mass hierarchy. Recently the possibility to deploy up to 10 times more natural tellurium is being developed, by which SNO+ could explore, in the near future, deep into the parameter space for the inverted hierarchy. Designed as a general purpose neutrino experiment, SNO+ can additionally measure the reactor neutrino oscillations, geo-neutrinos in a geologically-interesting location, watch supernova neutrinos and measure low energy solar neutrinos. A first commissioning phase with the detector filled with water has started in autumn 2014, while full running with water will take place in 2015. Transition to the scintillator phase will start towards the end of 2015. The 0n2b decay phase is foreseen for the 2016.

Theoretical aspects of double beta decay

International Nuclear Information System (INIS)

Haxton, W.C.

1984-01-01

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

Nuclear structure and double beta decay

International Nuclear Information System (INIS)

Vogel, P.

1988-01-01

Double beta decay is a rare transition between two nuclei of the same mass number A involving a change of the nuclear charge Z by two units. It has long been recognized that the Oν mode of double beta decay, where two electrons and no neutrinos are emitted, is a powerful tool for the study of neutrino properties. Its observation would constitute a convincing proof that there exists a massive Majorana neutrino which couples to electrons. Double beta decay is a process involving an intricate mixture of particle physics and physics of the nucleus. The principal nuclear physics issues have to do with the evaluation of the nuclear matrix elements responsible for the decay. If the authors wish to arrive at quantitative answers for the neutrino properties the authors have no choice but to learn first how to understand the nuclear mechanisms. The authors describe first the calculation of the decay rate of the 2ν mode of double beta decay, in which two electrons and two antineutrinos are emitted

Search for new physics with neutrinoless double beta decay

International Nuclear Information System (INIS)

Klapdor-Kleingrothaus, H.V.; Baudis, L.; Hellmig, J.; Hirsch, M.; Kolb, S.; Paes, H.; Ramachers, Y.

1999-01-01

Neutrinoless double beta decay (0νββ) is one of the most sensitive approaches to test particle physics beyond the standard model. During the last years, besides the most restrictive limit on the effective Majorana neutrino mass, the analysis of new contributions by the Heidelberg group led to bounds on left-right-symmetric models, leptoquarks and R-parity violating models competitive to recent accelerator limits, which are of special interest in view of the HERA anomaly at large Q 2 and x. These new results deduced from the Heidelberg-Moscow double beta decay experiment are reviewed. Also an outlook on the future of double beta decay, the GENIUS proposal, is given

The majorana {sup 76}Ge double-beta decay project

Energy Technology Data Exchange (ETDEWEB)

Aalseth, C.E.; Adles, E.; Anderson, D.; Avignone, F.T.; Barabash, A.; Bowyer, T.W.; Brodzinski, R.L.; Brudanin, V.; Champangne, A.; Collar, J.I.; Doe, P.J.; Egorov, S.; Elliott, S.R.; Farach, H.A.; Gaitskell, R.; Jordan, D.; Jain, R.K.; Kazkaz, K.; King, G.; Kochetov, O.; Konovalov, S.; Kouzes, R.; Miley, H.S.; Palms, J.M.; Pitts, W.K.; Reeves, J.H.; Robertson, R.G.H.; Rohm, R.; Sandukovsky, S.; Smith, L.E.; Stekhanov, V.; Thompson, R.C.; Tornow, W.; Umatov' , V.; Warner, R.; Webb, J.; Wilkerson, J.F.; Young, A

2003-07-01

The interest and relevance of next-generation 0{sub v} {beta}{beta}-decay experiments is increasing. Even with nonzero neutrino mass strongly suggested by solar and atmospheric neutrino experiments sensitive to {delta}m{sup 2}, 0{sub v} {beta}{beta}-decay experiments are still the only way to establish the Dirac or Majorana nature of neutrinos by measuring the effective electron neutrino mass, . In addition, the atmospheric neutrino oscillation experiments imply that at least one neutrino has a mass greater than about 50 meV. The Majorana Experiment expects to probe an effective neutrino mass near this critical value. Majorana is a next-generation {sup 76}Ge double-beta decay search. It will employ 500 kg of Ge, isotopically enriched to 86% in {sup 76}Ge, in the form of {approx} 200 detectors in a close-packed array. Each crystal will be electronically segmented and each segment fitted with pulse-shape analysis electronics. This combination of segmentation and pulse-shape analysis significantly improves our ability to discriminate neutrinoless double beta-decay from internal cosmogenic {sup 68}Ge and {sup 60}Co. The half-life sensitivity is estimated to be 4.2 x 10{sup 27} y corresponding to a range of {<=} 20 - 70 meV, depending on the nuclear matrix elements used to interpret the data.

Challenges in Double Beta Decay

Directory of Open Access Journals (Sweden)

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.

Nuclear transparency and double beta decay of molybdenum 100

International Nuclear Information System (INIS)

Nicholson, H.W.

1992-08-01

Data taking is now complete on a double beta decay experiment which has been carried out with collaborators from the Lawrence Berkeley Laboratory, the University of New Mexico, and the Idaho National Engineering Laboratory, and work is continuing on a second collaborative experiment, AGS experiment 850 at the Brookhaven National Laboratory to study nuclear color transparency. In March, the experimental apparatus used to search for double beta decay in molybdenum 100 in the Consil silver mine in Osburn, Idaho was dismantled, and the data analysis is in its final stages. No evidence has been seen for the O + → O + mode of zero neutrino double beta decay collaborators with a 1σ lifetime limit of 3 x 10 22 years. This limit is 7.5 times greater than the limit we published previously in Physical Review Letters in 1989. Backgrounds have been simulated and fits are currently underway to a simulated O + → 2 + mode of zero neutrino double beta decay to improve on a very preliminary 1σ lifetime limit of 2.3 x 10 21 years presented at the April, 1992 meeting of the APS in Washington. A scintillating fiber detector with three Hamamatsu, H4140, 256 channel multianode phototubes has been built, instrumented, and tested in the May--July 1992 run in the EVA detector at Brookhaven Laboratory's AGS. Preliminary results from this detector have been disappointing. it is likely that the detector will have to be substantially redesigned before the 1993 AGS run

Double-beta decay processes from lattice quantum chromodynamics

Science.gov (United States)

Davoudi, Zohreh; Tiburzi, Brian; Wagman, Michael; Winter, Frank; Chang, Emmanuel; Detmold, William; Orginos, Kostas; Savage, Martin; Shanahan, Phiala; Nplqcd Collaboration

2017-09-01

While an observation of neutrinoless double-beta decay in upcoming experiments will establish that the neutrinos are Majorana particles, the underlying new physics responsible for this decay can only be constrained if the theoretical predictions of the rate are substantially refined. This talk demonstrates the roadmap in connecting the underlying high-scale theory to the corresponding nuclear matrix elements, focusing mainly on the nucleonic matrix elements in the simplest extension of Standard Model in which a light Majorana neutrino is mediating the process. The role of lattice QCD and effective field theory in this program, in particular, the prospect of a direct matching of the nn to pp amplitude to lattice QCD will be discussed. As a first step towards this goal, the results of the first lattice QCD calculation of the relevant matrix element for neutrinofull double-beta decay will be presented, albeit with unphysical quark masses, along with important lessons that could impact the calculations of nuclear matrix elements involved in double-beta decays of realistic nuclei.

The CUORE neutrinoless double-beta decay experiment

International Nuclear Information System (INIS)

Banks, T.I.

2014-01-01

CUORE is an upcoming experiment designed to search for neutrinoless double-beta decay (0νββ) decay in 130 Te. Observation of the process would be a major finding because it would unambiguously establish that neutrinos are Majorana particles (i.e., their own antiparticles) as well as provide information about the absolute neutrino mass scale. The CUORE detector will consist of 988 identical TeO 2 crystal bolometers (containing 206 kg of 130 Te in total) arranged into 19 towers and cooled to about 10 mK at the underground Gran Sasso National Laboratory (LNGS), Italy, which provides the low-background environment necessary for rare event searches of this kind. A predecessor experiment, Cuoricino, ran from 2003-2008 at LNGS and served as a learning ground for CUORE, which will be 20 times larger and exhibit much lower backgrounds. The CUORE detector assembly line has produced its first tower, designated CUORE-0, which is expected to come online in the former Cuoricino cryostat in October 2012 and take data for about 2 years while 19 CUORE towers are assembled. CUORE data taking is expected for 2015-2019. (author)

The 76Ge Program to Search for Neutrinoless Double-Beta Decay

Science.gov (United States)

Guiseppe, Vincente

2017-09-01

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 and Gerda Collaborations are operating arrays of high purity Ge detectors to search for neutrinoless double-beta decay in 76Ge. The Majorana Demonstrator is operating at the Sanford Underground Research Facility in South Dakota while the Gerda experiment is operating at LNGS in Italy. The Gerda and Majorana Demonstrator experiments have achieved the lowest backgrounds in the neutrinoless double-beta decay region of interest. These results, coupled with the superior energy resolution (0.1%) of Ge detectors demonstrate that 76Ge is an ideal isotope for a large next generation experiment. The LEGEND collaboration, with 220 members from 47 institutions around the world, has been formed to pursue a ton scale 76Ge experiment. Building on the successes of Gerda and Majorana, the LEGEND collaboration aims to develop a phased neutrinoless double-beta decay experimental program with discovery potential at a half-life significantly longer than 1027 years. This talk will present the initial results from the Majorana Demonstrator and Gerda experiments and the plan for the LEGEND program.

Tables of double beta decay data

Energy Technology Data Exchange (ETDEWEB)

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.

Double beta decay of 82Se

International Nuclear Information System (INIS)

Elliott, S.R.; Hahn, A.A.; Moe, M.K.; Nelson, M.A.; Vient, M.A.

1992-01-01

The two-neutrino double beta decay of 82 Se has been measured during a 20 244 h run resulting in a half-life of 1.08 -0.06 +0.26 x10 20 years (68% C.L.). No candidate events for the zero-neutrino double beta decay during 21 924 h results in a half-life limit of 2.7x10 22 years at the 68% confidence level

Main features of detectors and isotopes to investigate double beta decay with increased sensitivity

Science.gov (United States)

Barabash, A. S.

2018-03-01

The current situation in double beta decay experiments, the characteristics of modern detectors and the possibility of increasing the sensitivity to neutrino mass in future experiments are discussed. The issue of the production and use of enriched isotopes in double beta decay experiments is discussed in addition.

Search of Neutrinoless Double Beta Decay with the GERDA Experiment

Science.gov (United States)

Agostini, M.; Allardt, M.; Bakalyarov, A. M.; Balata, M.; Barabanov, I.; Baudis, L.; Bauer, C.; Becerici-Schmidt, N.; Bellotti, E.; Belogurov, S.; Belyaev, S. T.; Benato, G.; Bettini, A.; Bezrukov, L.; Bode, T.; Borowicz, D.; Brudanin, V.; Brugnera, R.; Budjáš, D.; Caldwell, A.; Cattadori, C.; Chernogorov, A.; D'Andrea, V.; Demidova, E. V.; Domula, A.; Doroshkevich, E.; Egorov, V.; Falkenstein, R.; Fedorova, O.; Freund, K.; Frodyma, N.; Gangapshev, A.; Garfagnini, A.; Gooch, C.; Gotti, C.; Grabmayr, P.; Gurentsov, V.; Gusev, K.; Hampel, W.; Hegai, A.; Heisel, M.; Hemmer, S.; Heusser, G.; Hoffmann, W.; Hult, M.; Inzhechik, L. V.; Ioannucci, L.; Janicksó Csáthy, J.; Jochum, J.; Junker, M.; Kazalov, V.; 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.; Macolino, C.; Majorovits, B.; Maneschg, W.; Marissens, G.; Medinaceli, E.; Misiaszek, M.; Moseev, P.; Nemchenok, I.; Nisi, S.; Palioselitis, D.; Panas, K.; Pandola, L.; Pelczar, K.; Pessina, G.; Pullia, A.; Reissfelder, M.; Riboldi, S.; Rumyantseva, N.; Sada, C.; Salathe, M.; Schmitt, C.; Schneider, B.; Schreiner, J.; Schulz, O.; Schwingenheuer, B.; Schönert, S.; Seitz, H.; Selivalenko, O.; Shevchik, E.; Shirchenko, M.; Simgen, H.; Smolnikov, A.; Stanco, L.; Stepaniuk, M.; Strecker, H.; Ur, C. A.; Vanhoefer, L.; Vasenko, A. A.; Veresnikova, A.; von Sturm, K.; Wagner, V.; Walter, M.; Wegmann, A.; Wester, T.; Wiesinger, C.; Wilsenach, H.; Wojcik, M.; Yanovich, E.; Zavarise, P.; Zhitnikov, I.; Zhukov, S. V.; Zinatulina, D.; Zuber, K.; Zuzel, G.

2016-04-01

The GERDA (GERmanium Detector Array) is an experiment for the search of neutrinoless double beta decay (0 νββ) in 76Ge, located at Laboratori Nazionali del Gran Sasso of INFN (Italy). In the first phase of the experiment, a 90% confidence level (C.L.) sensitivity of 2.4 ṡ1025 yr on the 0 νββ decay half-life was achieved with a 21.6 kgṡyr exposure and an unprecedented background index in the region of interest of 10-2 counts/(keVṡkgṡyr). No excess of signal events was found, and an experimental lower limit on the half-life of 2.1 ṡ 1025 yr (90% C.L.) was established. Correspondingly, the limit on the effective Majorana neutrino mass is mee < 0.2- 0.4 eV, depending on the considered nuclear matrix element. The previous claim for evidence of a 0 νββ decay signal is strongly disfavored, and the field of research is open again.

Neutrinoless double beta decay

Indian Academy of Sciences (India)

2012-10-06

Oct 6, 2012 ... Anyhow, the 'multi-isotope' ansatz is needed to compensate for matrix element ... The neccessary half-life requirement to touch this ... site energy depositions (like double beta decay) and multiple site interactions (most of.

Probing new physics models of neutrinoless double beta decay with SuperNEMO

Energy Technology Data Exchange (ETDEWEB)

Arnold, R. [CNRS/IN2P3, IPHC, Universite de Strasbourg, Strasbourg (France); Augier, C.; Bongrand, M.; Garrido, X.; Jullian, S.; Sarazin, X.; Simard, L. [CNRS/IN2P3, LAL, Universite Paris-Sud 11, Orsay (France); Baker, J.; Caffrey, A.J.; Horkley, J.J.; Riddle, C.L. [INL, Idaho Falls, ID (United States); Barabash, A.S.; Konovalov, S.I.; Umatov, V.I.; Vanyushin, I.A. [Institute of Theoretical and Experimental Physics, Moscow (Russian Federation); Basharina-Freshville, A.; Evans, J.J.; Flack, R.; Holin, A.; Kauer, M.; Richards, B.; Saakyan, R.; Thomas, J.; Vasiliev, V.; Waters, D. [University College London, London (United Kingdom); Brudanin, V.; Egorov, V.; Kochetov, O.; Nemchenok, I.; Timkin, V.; Tretyak, V.; Vasiliev, R. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Cebrian, S.; Dafni, T.; Irastorza, I.G.; Gomez, H.; Iguaz, F.J.; Luzon, G.; Rodriguez, A. [University of Zaragoza, Zaragoza (Spain); Chapon, A.; Durand, D.; Guillon, B.; Mauger, F. [Universite de Caen, LPC Caen, ENSICAEN, Caen (France); Chauveau, E.; Hubert, P.; Hugon, C.; Lutter, G.; Marquet, C.; Nachab, A.; Nguyen, C.H.; Perrot, F.; Piquemal, F.; Ricol, J.S. [UMR 5797, Universite de Bordeaux, Centre d' Etudes Nucleaires de Bordeaux Gradignan, Gradignan (France); UMR 5797, CNRS/IN2P3, Centre d' Etudes Nucleaires de Bordeaux Gradignan, Gradignan (France); Deppisch, F.F.; Jackson, C.M.; Nasteva, I.; Soeldner-Rembold, S. [Univ. of Manchester (United Kingdom); Diaz, J.; Monrabal, F.; Serra, L.; Yahlali, N. [CSIC - Univ. de Valencia, IFIC (Spain); Fushima, K.I. [Tokushima Univ., Tokushima (Japan); Holy, K.; Povinec, P.P.; Simkovic, F. [Comenius Univ., FMFI, Bratislava (Slovakia); Ishihara, N. [KEK, Tsukuba, Ibaraki (Japan); Kovalenko, V. [CNRS/IN2P3, IPHC, Univ. de Strasbourg (France); Joint Inst. for Nuclear Research, Dubna (Russian Federation); Lamhamdi, T. [USMBA, Fes (Morocco); Lang, K.; Pahlka, R.B. [Univ. of Texas, Austin, TX (United States)] (and others)

2010-12-15

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. (orig.)

Neutrinoless double beta decay in type I+II seesaw models

Energy Technology Data Exchange (ETDEWEB)

Borah, Debasish [Department of Physics, Tezpur University,Tezpur-784028 (India); Dasgupta, Arnab [Institute of Physics, Sachivalaya Marg,Bhubaneshwar-751005 (India)

2015-11-30

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.

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

International Nuclear Information System (INIS)

Fairbank, William

2016-01-01

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 "1"3"6Xe, 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 1.9x10"2"5 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

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

Energy Technology Data Exchange (ETDEWEB)

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

Why search for double beta decay?

International Nuclear Information System (INIS)

Kayser, B.

1988-01-01

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

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

Science.gov (United States)

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.

Neutrinoless double beta decay search with SNO+

Directory of Open Access Journals (Sweden)

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.

Semiconductor-based experiments for neutrinoless double beta decay search

International Nuclear Information System (INIS)

Barnabé Heider, Marik

2012-01-01

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 116 Cd. Majorana and GERDA will use isotopically enriched high purity Ge detectors to search for 0νββ-decay of 76 Ge. Their aim is to achieve a background ⩽10 −3 counts/(kg⋅y⋅keV) 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 76 Ge. An overview and a comparison of these three experiments will be presented together with the latest results and developments.

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

International Nuclear Information System (INIS)

Morales, A.; Nunez-Lagos, R.; Morales, J.; Puimedon, J.; Villar, J.A.; Dassie, D.; Hubbert, Ph.; Leccia, F.; Mennrath, P.; Villard, M.

1987-01-01

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

Background constrains of the SuperNEMO experiment for neutrinoless double beta-decay searches

Energy Technology Data Exchange (ETDEWEB)

Povinec, Pavel P.

2017-02-11

The SuperNEMO experiment is a new generation of experiments dedicated to the search for neutrinoless double beta-decay, which if observed, would confirm the existence of physics beyond the Standard Model. It is based on the tracking and calorimetry techniques, which allow the reconstruction of the final state topology, including timing and kinematics of the double beta-decay transition events, offering a powerful tool for background rejection. While the basic detection strategy of the SuperNEMO detector remains the same as of the NEMO-3 detector, a number of improvements were accomplished for each of detector main components. Upgrades of the detector technologies and development of low-level counting techniques ensure radiopurity control of construction parts of the SuperNEMO detector. A reference material made of glass pellets has been developed to assure quality management and quality control of radiopurity measurements. The first module of the SuperNEMO detector (Demonstrator) is currently under construction in the Modane underground laboratory. No background event is expected in the neutrinoless double beta-decay region in 2.5 years of its operation using 7 kg of {sup 82}Se. The half-life sensitivity of the Demonstrator is expected to be >6.5·10{sup 24} y, corresponding to an effective Majorana neutrino mass sensitivity of |0.2−0.4| eV (90% C.L.). The full SuperNEMO experiment comprising of 20 modules with 100 kg of {sup 82}Se source should reach an effective Majorana neutrino mass sensitivity of |0.04−0.1| eV, and a half-life limit 1·10{sup 26} y. - Highlights: • SuperNEMO detector for 2β0ν-decay of {sup 82}Se should reach half-life limit of 10{sup 26} y. • Radiopurity of the SuperNEMO internal detector parts was checked down to 0.1 mBq/kg. • Reference material of glass pellets was developed for underground γ-spectrometry.

Nuclear aspects of double-beta decay

International Nuclear Information System (INIS)

Stoica, S.; Paun, V.

2002-01-01

Calculations of the neutrinoless double-beta decay (0νββ) matrix elements are performed with the second quasi random phase approximation (SQRPA) method for several nuclei. The results display a weak dependence on the single particle basis used and the Ikeda sum rule is fulfilled with good accuracy. Comparing our calculations with similar ones performed with other QRPA-based methods we estimate the accuracy of these methods in the prediction of the (0νββ) decay matrix elements and neutrino mass parameter, which is settled to about 50% from their calculated values. Taking the most recent experimental limits for the neutrinoless double beta decay half-lives, we also deduced new limits for the neutrino mass parameter. (authors)

Double beta decay: recent developments and projections

International Nuclear Information System (INIS)

Avignone, F.T. III; Brodzinski, R.L.; Brown, D.P.; Evans, J.C. Jr.; Hensley, W.K.; Reeves, J.H.; Wogman, N.A.

1983-08-01

A report of recent events in both theoretical and experimental aspects of double beta decay is given. General theoretical considerations, recent developments in nuclear structure theory, geochronological determinations of half lives and ratios as well as laboratory experiments are discussed with emphasis on the past three years. Some projections are given. 28 references

Meson exchange currents and two neutrino double beta decay

International Nuclear Information System (INIS)

Simkovic, F.

1995-01-01

By using a field theory approach a detailed analysis of the two neutrino double beta decay amplitude has been performed. We have shown that the summation over the intermediate nuclear states in the present two neutrino double beta decay studies corresponds to a summation over a class of meson exchange diagrams. We offer some arguments showing that the two nucleon mechanism considered at present does not provide the main contribution to the two neutrino double beta decay amplitude. A new electron-gamma exchange mechanism for this process is suggested. 31 refs., 1 fig

Monte Carlo Simulation for the Majorana Neutrinoless Double-beta Decay Experiment

International Nuclear Information System (INIS)

Henning, Reyco; Majorana Collaboration

2005-01-01

The Majorana experiment is a proposed HPGe detector array that will primarily search for neutrinoless double-beta decay and dark matter. It will rely on pulse-shape discrimination and crystal segmentation to suppress backgrounds following careful materials selection. A critical aspect of the design phase of Majorana is a reliable simulation of the detector response, pulse formation, and its radioactive backgrounds. We are developing an adaptable and complete simulation based on GEANT 4 to address these requirements and the requirements of a modern, large collaboration experiment. The salient aspects of the simulation are presented. The Majorana experiment is presented in a parallel poster by Kareem Kazkaz

Future of double beta decay and dark matter searches - GENIUS

International Nuclear Information System (INIS)

Klapdor-Kleingrothaus, H. V.; Baudis, L.; Heusser, G.; Krivosheina, I. V.; Kolb, S.; Majorovits, B.; Nabi, J.-U.; Paes, H.

1999-01-01

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 further by a major step the present sensitivity for double beta decay and dark matter searches, we describe here a project, proposed recently [1], 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 MAJORANA DEMONSTRATOR Neutrinoless Double-Beta Decay Experiment

Directory of Open Access Journals (Sweden)

N. Abgrall

2014-01-01

Full Text Available The Majorana Demonstrator will search for the neutrinoless double-beta (ββ0ν decay of the isotope Ge 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.

The Milano-Gran Sasso double beta decay experiment: toward a 20-crystal array

International Nuclear Information System (INIS)

Alessandrello, A.; Brofferio, C.; Bucci, C.; Cremonesi, O.; Fiorini, E.; Giuliani, A.; Nucciotti, A.; Pavan, M.; Pessina, G.; Previtali, E.; Zanotti, L.

1996-01-01

TeO 2 thermal detectors are being used by the Milano group to search for neutrinoless double beta decay of 130 Te. An upper limit for neutrinoless decay half life of 2.1 x 10 22 yr at 90% CL obtained with a 334 g TeO 2 detector has been previously reported. To improve the sensitivity of the experiment an array of twenty 340 g TeO 2 crystals will be realised in the next future. As a first step toward the realisation of that experiment a 4 crystal detector has been tested in the Gran Sasso refrigerator. Detector performances, data acquisition and analysis are discussed. (orig.)

Double beta decays and neutrino masses

International Nuclear Information System (INIS)

Ejiri, Hiro

2006-01-01

Neutrino-less double beta decays(0νββ) are of great interest for studying the Majorana nature of ν's and the absolute ν-mass scale. The present report is a brief review of the 0νββ studies with emphasis on future experiments with the mass sensitivity of an order of 25∼100 meV and on experimental probes for investigating 0νββ nuclear matrix elements

Double beta decay: A theoretical overview

International Nuclear Information System (INIS)

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

The Majorana Zero-Neutrino Double-Beta Decay Experiment White Paper

International Nuclear Information System (INIS)

Gaitskell, R.; Barabash, A.; Konovalov, S.; Stekhanov, V.; Umatov, V.; Brudanin, V.; Egorov, S.; Webb, J.; Miley, Harry S.; Aalseth, Craig E.; Anderson, Dale N.; Bowyer, Ted W.; Brodzinski, Ronald L.; Jordan, David B.; Kouzes, Richard T.; Smith, Eric E.; Thompson, Robert C.; Warner, Ray A.; Tornow, W.; Young, A.; Collar, J.I.; Avignone, Frank T.; Palms, John M.; Doe, P J.; Elliott, Steven R.; Kazkaz, K.; Robertson, Hamish; Wilkerson, John

2002-01-01

The goal of the Majorana Experiment is to determine the effective Majorana mass of the electron neutrino. Detection of the neutrino mass implied by oscillation results in within our grasp. This exciting physics goal is best pursued using double-beta decay of germanium because of the historical and emerging advances in eliminating competing signals from radioactive backgrounds. The Majorana Experiment will consist of a large mass of 76Ge in the form of high-resolution detectors deep underground, searching for a sharp peak at the BB endpoint. We present here an overview of the entire project in order to help put in perspective the scope, the level and technical risk, and the readiness of the Collaboration to begin the undertaking

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

Directory of Open Access Journals (Sweden)

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.

Grand unification and the double beta-decay

International Nuclear Information System (INIS)

Faessler, A.

1992-01-01

Models of the unification of the electroweak and the strong interaction predict that the neutrino is a Majorana particle and therefore essentially identical with its own antiparticle. In such grand unified models the neutrino has also a finite mass and a slight right-handed weak interaction, since the model is left-right symmetric. These models have also left handed and right-handed vector bosons to mediate the weak interactions. If these models are correct the neutrinoless double beta-decay is feasable. Thus if one finds the neutrinoless double beta-decay one knows that the standard model can not be correct in which the neutrino is a Dirac particle and therefore different from its antiparticle. Although the neutrinoless double beta-decay has not been seen it is possible to extract from the lower limits of the lifetime against the double neutrinoless beta-decay upper limits for the effective electron-neutrino mass and for the effective mixing angle of the right-handed and the left-handed vector bosons mediating the weak interaction. One also can obtain an effective upper limit for the mass ratio of the light and the heavy vector bosons. The extraction of this physical quantities from the data is made difficult due to the fact that the weak interaction must not be diagonal in the representation of the mass matrix of the six neutrinos requested by such left-right symmetric models. (author)

Scalar-mediated double beta decay and LHC

International Nuclear Information System (INIS)

Gonzalez, L.; Helo, J.C.; Hirsch, M.; Kovalenko, S.G.

2016-01-01

The decay rate of neutrinoless double beta (0νββ) decay could be dominated by Lepton Number Violating (LNV) short-range diagrams involving only heavy scalar intermediate particles, known as “topology-II” diagrams. Examples are diagrams with diquarks, leptoquarks or charged scalars. Here, we compare the LNV discovery potentials of the LHC and 0νββ-decay experiments, resorting to three example models, which cover the range of the optimistic-pessimistic cases for 0νββ decay. We use the LHC constraints from dijet as well as leptoquark searches and find that already with 20/fb the LHC will test interesting parts of the parameter space of these models, not excluded by the current limits on 0νββ-decay.

Scalar-mediated double beta decay and LHC

Energy Technology Data Exchange (ETDEWEB)

Gonzalez, L. [Universidad Técnica Federico Santa María, Centro-Científico-Tecnológico de Valparaíso,Casilla 110-V, Valparaíso (Chile); Helo, J.C. [Universidad Técnica Federico Santa María, Centro-Científico-Tecnológico de Valparaíso,Casilla 110-V, Valparaíso (Chile); Departamento de Física, Facultad de Ciencias, Universidad de La Serena,Avenida Cisternas 1200, La Serena (Chile); Hirsch, M. [AHEP Group, Instituto de Física Corpuscular - C.S.I.C./Universitat de València,Edificio de Institutos de Paterna, Apartado 22085, E-46071 València (Spain); Kovalenko, S.G. [Universidad Técnica Federico Santa María, Centro-Científico-Tecnológico de Valparaíso,Casilla 110-V, Valparaíso (Chile)

2016-12-23

The decay rate of neutrinoless double beta (0νββ) decay could be dominated by Lepton Number Violating (LNV) short-range diagrams involving only heavy scalar intermediate particles, known as “topology-II” diagrams. Examples are diagrams with diquarks, leptoquarks or charged scalars. Here, we compare the LNV discovery potentials of the LHC and 0νββ-decay experiments, resorting to three example models, which cover the range of the optimistic-pessimistic cases for 0νββ decay. We use the LHC constraints from dijet as well as leptoquark searches and find that already with 20/fb the LHC will test interesting parts of the parameter space of these models, not excluded by the current limits on 0νββ-decay.

On the nuclear double beta decay: microscopic description

International Nuclear Information System (INIS)

Civitarese, Osvaldo

1989-01-01

This paper is devoted to the discussion of some problems related with microscopic descriptions of the nuclear double beta decay. It has been organized in the following order: 1) Review of the experimental situation; 2) Brief discussion of the theoretical aspects related to the current algebra, weak interaction, neutrino and majoron's status and 3) Elements of the standard nuclear theory involved in the calculation of transition densities for the nuclear double beta decay. (Author) [es

Double Beta Decay

International Nuclear Information System (INIS)

Fiorini, Ettore

2008-01-01

The importance of neutrinoless Double Beta Decay (DBD) is stressed in view of the recent results of experiments on neutrino oscillations which indicate that the difference between the squared masses of two neutrinos of different flavours is finite [For a recent review including neutrino properties and recent results see: Review of Particle Physics, J. of Phys. G: Nuclear and Particle Physics 33, 1]. As a consequence the mass of at least one neutrino has to be different from zero and it becomes imperative to determine its absolute value. The various experimental techniques to search for DBD are discussed together with the difficult problems of the evaluation of the corresponding nuclear matrix elements. The upper limits on neutrino mass coming from the results of the various experiments are reported together with the indication for a non zero value by one of them not confirmed so far. The two presently running experiments on neutrinoless DBD are briefly described together with the already approved or designed second generation searches aiming to reach the values on the absolute neutrino mass indicated by the results on neutrino oscillations

Measurement of Radon-Induced Backgrounds in the NEXT Double Beta Decay Experiment

Energy Technology Data Exchange (ETDEWEB)

Novella, P.; et al.

2018-04-02

The measurement of the internal 222Rn activity in the NEXT-White detector during the so-called Run-II period with 136Xe-depleted xenon is discussed in detail, together with its implications for double beta decay searches in NEXT. The activity is measured through the alpha production rate induced in the fiducial volume by 222Rn and its alpha-emitting progeny. The specific activity is measured to be $(37.5\\pm 2.3~\\mathrm{(stat.)}\\pm 5.9~\\mathrm{(syst.)})$~mBq/m$^3$. Radon-induced electrons have also been characterized from the decay of the 214Bi daughter ions plating out on the cathode of the time projection chamber. From our studies, we conclude that radon-induced backgrounds are sufficiently low to enable a successful NEXT-100 physics program, as the projected rate contribution should not exceed 0.2~counts/yr in the neutrinoless double beta decay sample.

Pulse-shape discrimination techniques for the COBRA double beta-decay experiment at LNGS

Science.gov (United States)

Zatschler, S.; COBRA Collaboration

2017-09-01

In modern elementary particle physics several questions arise from the fact that neutrino oscillation experiments have found neutrinos to be massive. Among them is the so far unknown nature of neutrinos: either they act as so-called Majorana particles, where one cannot distinguish between particle and antiparticle, or they are Dirac particles like all the other fermions in the Standard Model. The study of neutrinoless double beta-decay (0νββ-decay), where the lepton number conservation is violated by two units, could answer the question regarding the underlying nature of neutrinos and might also shed light on the mechanism responsible for the mass generation. So far there is no experimental evidence for the existence of 0νββ-decay, hence, existing experiments have to be improved and novel techniques should be explored. One of the next-generation experiments dedicated to the search for this ultra-rare decay is the COBRA experiment. This article gives an overview of techniques to identify and reject background based on pulse-shape discrimination.

Sensitivity of NEXT-100 to neutrinoless double beta decay

CERN Document Server

Martín-Albo, J.; Ferrario, P.; Nebot-Guinot, M.; Gómez-Cadenas, J.J.; Álvarez, V.; Azevedo, C.D.R.; Borges, F.I.G.; Cárcel, S.; Cebrián, S.; Cervera, A.; Conde, C.A.N.; Díaz, J.; Diesburg, M.; Esteve, R.; Fernandes, L.M.P.; Ferreira, A.L.; Freitas, E.D.C.; Gehman, V.M.; Goldschmidt, A.; González-Díaz, D.; Gutiérrez, R.M.; Henriques, C.A.O.; Hernando Morata, J.A.; Labarga, L.; Laing, A.; Lebrun, P.; Liubarsky, I.; López-March, N.; Lorca, D.; Losada, M.; Martínez-Lema, G.; Martínez, 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.; Rodríguez, J.; Santos, F.P.; dos Santos, J.M.F.; Serra, L.; Shuman, D.; Simón, 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-Ramírez, H.; Hauptman, J.

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.

Double beta decays and related subjects for particle and nuclear physics

International Nuclear Information System (INIS)

Ejiri, Hiroyasu

1991-01-01

Present status and some perspectives in 1990's are briefly given on double beta decays and related subjects. Subjects discussed are as follows I) Double beta decays without neutrinos, which require lepton number non-conservations and finite neutrino mass. II) Double beta decays followed by two neutrinos. III) Double weak processes with strangeness change ΔS = 2, leading to the H particle with 6 quarks of ss uu dd. IV) Charge non-conservation and electron decays. These are very rare nuclear processes studied by Ultra RAre-process NUclear Spectroscopy (URANUS). It is shown that URANUS is an important detector frontier of non-accelerator nuclear physics in 1990's. (orig.)

Search for neutrinoless double beta decay beyond GERDA

Energy Technology Data Exchange (ETDEWEB)

Schwingenheuer, Bernhard [MPI Kernphysik, Heidelberg (Germany)

2016-07-01

The search for neutrinoless double beta decay might be the only window to observe lepton number violation and to determine the nature of neutrinos. Is is therefore considered to be of highest relevance. The isotope Ge-76 has historically been most important for this search and the ongoing experiment GERDA has the lowest background of all experiments in the field. The proposed experimental program beyond GERDA (and Majorana) is presented.

Majorana neutrino masses and the neutrinoless double-beta decay

International Nuclear Information System (INIS)

Faessler, A.

2006-01-01

Neutrinoless double-beta decay is forbidden in the Standard Model of electroweak and strong interaction but allowed in most Grand Unified Theories (GUTs). Only if the neutrino is a Majorana particle (identical with its antiparticle) and if it has a mass is neutrinoless double-beta decay allowed. Apart from one claim that the neutrinoless double-beta decay in 76 Ge is measured, one has only upper limits for this transition probability. But even the upper limits allow one to give upper limits for the electron Majorana neutrino mass and upper limits for parameters of GUTs and the minimal R-parity-violating supersymmetric model. One further can give lower limits for the vector boson mediating mainly the right-handed weak interaction and the heavy mainly right-handed Majorana neutrino in left-right symmetric GUTs. For that, one has to assume that the specific mechanism is the leading one for neutrinoless double-beta decay and one has to be able to calculate reliably the corresponding nuclear matrix elements. In the present work, one discusses the accuracy of the present status of calculating of the nuclear matrix elements and the corresponding limits of GUTs and supersymmetric parameters

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

Energy Technology Data Exchange (ETDEWEB)

Schubert, Alexis G.; Aguayo, Estanislao; Avignone, F. T.; Zhang, C.; Back, Henning O.; Barabash, Alexander S.; Bergevin, M.; 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.; Leon, Jonathan D.; Doe, Peter J.; Efremenko, Yuri; Egorov, Viatcheslav; Ejiri, H.; Elliott, S. R.; Esterline, James H.; Fast, James E.; Fields, N.; Finnerty, P.; Fraenkle, Florian; Gehman, Victor M.; Giovanetti, G. K.; Green, M.; Guiseppe, Vincente; Gusey, K.; Hallin, A. L.; Hazama, R.; Henning, Reyco; Hime, Andrew; Hoppe, Eric W.; Horton, Mark; Howard, Stanley; Howe, Mark; Johnson, R. A.; Keeter, K.; Keillor, Martin E.; Keller, C.; Kephart, Jeremy D.; Kidd, M. F.; Knecht, A.; Kochetov, Oleg; Konovalov, S.; Kouzes, Richard T.; LaFerriere, Brian D.; LaRoque, B. H.; Leviner, L.; Loach, J. C.; MacMullin, S.; Marino, Michael G.; Martin, R. D.; Mei, Dong-Ming; Merriman, Jason H.; Miller, M. L.; Mizouni, Leila; Nomachi, Masaharu; Orrell, John L.; Overman, Nicole R.; Phillips, D.; Poon, Alan; Perumpilly, Gopakumar; Prior, Gersende; Radford, D. C.; Rielage, Keith; Robertson, R. G. H.; Ronquest, M. C.; Shima, T.; Shirchenko, M.; Snavely, Kyle J.; Sobolev, V.; Steele, David; Strain, J.; Thomas, K.; Timkin, V.; Tornow, Werner; Vanyushin, I.; Varner, R. L.; Vetter, Kai; Vorren, Kris R.; Wilkerson, J. F.; Wolfe, B. A.; Yakushev, E.; Young, A.; Yu, Chang-Hong; Yumatov, Vladimir

2012-09-28

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 76Ge. The DEMONSTRATOR will contain 40 kg of germanium; up to 30 kg will be enriched to 86% in 76Ge. 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 76Ge neutrinoless double-beta decay Q-value of 2039 keV.

Simulated progress in double-beta decay

International Nuclear Information System (INIS)

Miley, H.S.; Arthur, R.J.; Avignone, F.T.

1993-09-01

A Monte Carlo code has been developed to accurately simulate double-beta decay measurements. Coincident gamma rays, beta spectra, and angular correlations have been added to adequately simulate a complete 100 Mo nuclear decay and provide corrections to experimentally determined detector efficiencies. This code has been used to strip certain low-background spectra obtained in the Homestake gold mine in Lead, SD, for the purpose of extremely sensitive materials assay for the construction of new, large, enriched germanium detectors. Assays as low as 9 μBq/g of 210 Pb in lead shielding were obtained

Is neutrinoless double beta decay suppressed

International Nuclear Information System (INIS)

Tomoda, T.

1989-01-01

Much effort has been devoted to the study of nuclear double beta decay, since the observation of a neutrinoless double beta (OνΒΒ) decay would be clear evidence that the electron neutrino is a Majorana particle. The OνΒΒ decay is caused by a finite Majorana neutrino mass and/or an admixture of right-handed leptonic currents. In order to relate these quantities to OνΒΒ decay rates, we need nuclear matrix elements, which are model dependent. One of the possibilities of testing nuclear models employed in such analysis is to calculate the experimentally known rates of ΒΒ decay with emission of two neutrinos (2νΒΒ decay) which occurs independently of the nature of the neutrino. There was a long-standing difficulty in such attempts that the calculated 2νΒΒ decay rates turned out to be always too large by one to two orders of magnitude. Trying to overcome such difficulty, Klapdor and Grotz as well as Vogel and Zirnbauer showed in their calculation using schematic effective interactions such that 2νΒΒ decay rates can get reduced considerably due to the nuclear ground state correlations. This paper reports that the suppression is ascribed to that of the virtual Gamow-Teller transitions from the excited 1 + states of the intermediate odd-odd -even nucleus

LBL/UCSB 76Ge double beta decay experiment: first results

International Nuclear Information System (INIS)

Goulding, F.S.; Cork, C.P.; Landis, D.A.

1984-10-01

A paper given at the IEEE Nuclear Science Symposium last year presented the scientific justification for this experiment and discussed the design of the detector system. At the present time two of the dual detector systems (i.e., four out of a final total of eight detectors) are operating in the complete active/passive shield in the low background laboratory at LBL. Early results (1620 h) of an experiment using two detectors yield a limit of 4 x 10 22 years (68% confidence) for the half life of the neutrinoless double beta decay (ββ/sub o nu/) of 76 Ge. Although this experiment was carried out above ground, the result approaches those achieved by other groups in deep underground laboratories. Based on studies of the origins of background in our system, we hope to reach a limit of 3 x 10 23 years (or more) in a two month/four detector experiment to be carried out soon in an underground facility

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

Science.gov (United States)

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.

Neutrinoless double-beta decay and dark matter search with GENIUS

International Nuclear Information System (INIS)

Klapdor-Kleingrothaus, H.V.; Kolb, S.

2000-01-01

The potential of the GENIUS (GErmanium in liquid NItrogen Underground Setup) experiment, proposed the successor of the Heidelberg-Moscow experiment, for the search for neutrinoless double-beta decay, the direct search for neutralino Cold Dark Matter and for other physics beyond the Standard Model are presented. The current status of the Heidelberg-Moscow experiment will be reviewed [ru

Neutrinoless double-beta decay and dark matter search with GENIUS

International Nuclear Information System (INIS)

Klapdor-Kleingrothaus, H.V.; Kolb, St.

2000-01-01

The potential of the GENIUS (GErmanium in liquid NItrogen Underground Setup) experiment, proposed as the successor of the Heidelberg-Moscow experiment, for the search for neutrinoless double-beta decay, the direct search for neutralino Cold Dark Matter, and for other physics beyond the Standard Model will be presented. The current status of the Heidelberg-Moscow experiment will be reviewed

Neutrinoless double beta decay searches with 76Ge

CERN Multimedia

CERN. Geneva

2017-01-01

The search for neutrinoless double beta decay might be the only window to observe lepton number violation. Its observation would favour the leptogenesis mechanism for the explanation of the baryon asymmetry of the universe and is therefore considered to be of highest relevance. The isotope 76Ge has historically been most important for this search and the ongoing experiment GERDA has the lowest background of all experiments in the field. The talk reviews the motivation, the current status of experiments and future programs.

Constraining neutrinoless double beta decay

International Nuclear Information System (INIS)

Dorame, L.; Meloni, D.; Morisi, S.; Peinado, E.; Valle, J.W.F.

2012-01-01

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.

Search for neutrinoless double beta decay in {sup 136}Xe with EXO-200

Energy Technology Data Exchange (ETDEWEB)

Feldmeier, Wolfhart

2015-02-19

Several properties of neutrinos, such as their absolute mass, their possible Majorana nature or the mechanisms that lead to small neutrino masses, are still unknown. The EXO-200 experiment is trying to answer some of these questions by searching for the hypothetical neutrinoless double beta decay of the isotope {sup 136}Xe. This thesis describes an analysis of two years of detector data, which yields a lower limit on the half-life of neutrinoless double beta decay of {sup 136}Xe of 1.1 x 10{sup 25} years.

Sensitivity and Discovery Potential of CUORE to Neutrinoless Double-Beta Decay

Energy Technology Data Exchange (ETDEWEB)

Alessandria, F; Ardito, R; Artusa, DR; III, FTA; Azzolini, O; Balata, M; Banks, TI; Bari, G; Beeman, J; Bellini, F; Bersani, A; Biassoni, M; Bloxham, T; Brofferio, C; Bucci, C; Cai, XZ; Canonica, L; Cao, X; Capelli, S; Carbone, L; Cardani, L; Carrettoni, M; Casali, N; Chiesa, D; Chott, N; Clemenza, M; Cosmelli, C; Cremonesi, O; Creswick, RJ; Dafinei, I; Dally, A; Datskov, V; Biasi, AD; Deninno, MM; Domizio, SD; Vacri, MLD; Ejzak, L; Faccini, R; Fang, DQ; Farach, HA; Faverzani, M; Fernandes, G; Ferri, E; Ferroni, F; Fiorini, E; Franceschi, MA; Freedman, SJ; Fujikawa, BK; Giachero, A; Gironi, L; Giuliani, A; Goett, J; Gorla, P; Gotti, C; Guardincerri, E; Gutierrez, TD; Haller, EE; Han, K; Heeger, KM; Huang, HZ; Kadel, R; Kazkaz, K; Keppel, G; Kogler, L; Kolomensky, YG; Lenz, D; Li, YL; Ligi, C; Liu, X; Ma, YG; Maiano, C; Maino, M; Martinez, M; Maruyama, RH; Mei, Y; Moggi, N; Morganti, S; Napolitano, T; Newman, S; Nisi, S; Nones, C; Norman, EB; Nucciotti, A; O' Donnell, T; Orio, F; Orlandi, D; Ouellet, JL; Pallavicini, M; Palmieri, V; Pattavina, L; Pavan, M; Pedretti, M; Pessina, G; Piperno, G; Pirro, S; Previtali, E; Rampazzo, V; Rimondi, F; Rosenfeld, C; Rusconi, C; Sala, E; Sangiorgio, S; Scielzo, ND; Sisti, M; Smith, AR; Stivanello, F; Taffarello, L; Tenconi, M; Tian, WD; Tomei, C; Trentalange, S; Ventura, G; Vignati, M; Wang, BS; Wang, HW; Wise, T; Woodcraft, A; Zanotti, L; Zarra, C; Zhu, BX; Zucchelli, S

2017-07-06

We present a study of the sensitivity and discovery potential 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 for various background scenarios are presented, and an extension of the sensitivity formulation to the discovery potential case is also discussed. 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$0v\\atop{1/2}$(1θ) = 1.6 \\times 10²⁶ y and thus a potential to probe the effective Majorana neutrino mass down to 40-100 meV; the sensitivity at 1.64 sigma, which corresponds to 90% C.L., will be T$0v\\atop{1/2}$(1.64θ) = 9.5 \\times 10²⁵ y. 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.

Tables of double beta decay data

International Nuclear Information System (INIS)

Tretyak, V.I.

1995-01-01

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

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

Science.gov (United States)

Canonica, L.

2016-08-01

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.

GERDA - a new neutrinoless double beta experiment using 76Ge

International Nuclear Information System (INIS)

Meierhofer, G

2011-01-01

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 76 Ge, an ideal candidate as it is acting as source and detector simultaneously. Germanium detectors, isotopically enriched in 76 Ge 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.

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

Science.gov (United States)

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.

Status of evidence for neutrinoless double beta decay, and the future. Genius and genius-TF

International Nuclear Information System (INIS)

Klapdor-Kleingrothaus, H.V.

2004-01-01

The first evidence for neutrinoless double beta decay has been observed in the HEIDELBERG-MOSCOW experiment, which is the most sensitive double beta decay experiment since ten years. This is the first evidence for lepton number violation and proves that the neutrino is a Majorana particle. It further shows that neutrino masses are degenerate. In addition it puts several stringent constraints on other physics beyond the Standard Model. The result from the HEIDEL-BERG-MOSCOW experiment is consistent with recent results from CMB investigations, with high energy cosmic rays, with the result from the g-2 experiment and with recent theoretical work. It is indirectly supported by the analysis of other Ge double beta experiments. The new project GENIUS will cover a wide range of the parameter space of predictions of SUSY for neutralinos as cold dark matter. Further it has the potential to be a real-time detector for low-energy (pp and 7 Be) solar neutrinos. A GENIUS Test Facility has come into operation on May 5, 2003. This is the first time that this novel technique for extreme background reduction in search for rare decays is applied under the background conditions of an underground laboratory. (author)

Double beta decay searches with thermal detectors

International Nuclear Information System (INIS)

Pirro, Stefano

2006-01-01

Double beta decay searches have become more and more important in the last few years. The 'second generation' experiments will allow to explore the inverse hierarchy region but, due to the uncertainties in the nuclear matrix elements, none of them will be able to cover completely the allowed region. Thus the need to investigate different DBD emitters becomes more important. The bolometric technique is only one able to study different nuclei with the proper energy resolution, key point for the future experiments. The possibility to reject the natural background arising from fast neutrons and alpha particles was recently directly proved with thermal bolometers, using the double read out (heat and scintillation). This new technique offers the possibility to reach background levels two orders of magnitude smaller with respect to the ones of the next planned experiments, aiming the possibility to investigate direct hierarchy region. (author)

NEUTRINOLESS DOUBLE BETA DECAY: AN EXTREME CHALLENGE

Directory of Open Access Journals (Sweden)

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.

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

Energy Technology Data Exchange (ETDEWEB)

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.)

Search for the Neutrino Less Double Beta Decay

Energy Technology Data Exchange (ETDEWEB)

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 m_ββ 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

Neutron-induced Backgrounds in 134Xe for Large-Scale Neutrinoless Double-Beta Decay Experiments

Science.gov (United States)

Moriguchi, Nina; Kidd, Mary; Tornow, Werner

2016-09-01

136Xe is used in large neutrinoless double-beta (0 νββ) decay experiments, such as KamLAND- Zen and EXO 200. Though highly purified, 136Xe still contains a significant amount of 134Xe. Recently, a new nuclear energy level was found in 134Xe. If 134Xe decays from this proposed excited state, it will emit a 2485.7 keV gamma ray. Because this energy lies near the region of interest of 136Xe νββ decay experiments (Q value 2457.8 keV), it could make a significant contribution to the background. A purified gaseous sample of 134Xe will be irradiated with neutrons of an incident energy of 4.0 MeV at Triangle Universities Nuclear Laboratory and monitored with high-purity germanium detectors. The spectra obtained from these detectors will be analyzed for the presence of the 2581 keV gamma ray. We will report on the status of this experiment. Future plans include expanding this measurement to higher initial neutron energies. Tennesse Tech University CISE Grant program.

The large enriched germanium experiment for neutrinoless double beta decay (LEGEND)

Science.gov (United States)

Abgrall, N.; Abramov, A.; Abrosimov, N.; Abt, I.; Agostini, M.; Agartioglu, M.; Ajjaq, A.; Alvis, S. I.; Avignone, F. T.; Bai, X.; Balata, M.; Barabanov, I.; Barabash, A. S.; Barton, P. J.; Baudis, L.; Bezrukov, L.; Bode, T.; Bolozdynya, A.; Borowicz, D.; Boston, A.; Boston, H.; Boyd, S. T. P.; Breier, R.; Brudanin, V.; Brugnera, R.; Busch, M.; Buuck, M.; Caldwell, A.; Caldwell, T. S.; Camellato, T.; Carpenter, M.; Cattadori, C.; Cederkäll, J.; Chan, Y.-D.; Chen, S.; Chernogorov, A.; Christofferson, C. D.; Chu, P.-H.; Cooper, R. J.; Cuesta, C.; Demidova, E. V.; Deng, Z.; Deniz, M.; Detwiler, J. A.; Di Marco, N.; Domula, A.; Du, Q.; Efremenko, Yu.; Egorov, V.; Elliott, S. R.; Fields, D.; Fischer, F.; Galindo-Uribarri, A.; Gangapshev, A.; Garfagnini, A.; Gilliss, T.; Giordano, M.; Giovanetti, G. K.; Gold, M.; Golubev, P.; Gooch, C.; Grabmayr, P.; Green, M. P.; Gruszko, J.; Guinn, I. S.; Guiseppe, V. E.; Gurentsov, V.; Gurov, Y.; Gusev, K.; Hakenmüeller, J.; Harkness-Brennan, L.; Harvey, Z. R.; Haufe, C. R.; Hauertmann, L.; Heglund, D.; Hehn, L.; Heinz, A.; Hiller, R.; Hinton, J.; Hodak, R.; Hofmann, W.; Howard, S.; Howe, M. A.; Hult, M.; Inzhechik, L. V.; Csáthy, J. Janicskó; Janssens, R.; Ješkovský, M.; Jochum, J.; Johansson, H. T.; Judson, D.; Junker, M.; Kaizer, J.; Kang, K.; Kazalov, V.; Kermadic, Y.; Kiessling, F.; Kirsch, A.; Kish, A.; Klimenko, A.; Knöpfle, K. T.; Kochetov, O.; Konovalov, S. I.; Kontul, I.; Kornoukhov, V. N.; Kraetzschmar, T.; Kröninger, K.; Kumar, A.; Kuzminov, V. V.; Lang, K.; Laubenstein, M.; Lazzaro, A.; Li, Y. L.; Li, Y.-Y.; Li, H. B.; Lin, S. T.; Lindner, M.; Lippi, I.; Liu, S. K.; Liu, X.; Liu, J.; Loomba, D.; Lubashevskiy, A.; Lubsandorzhiev, B.; Lutter, G.; Ma, H.; Majorovits, B.; Mamedov, F.; Martin, R. D.; Massarczyk, R.; Matthews, J. A. J.; McFadden, N.; Mei, D.-M.; Mei, H.; Meijer, S. J.; Mengoni, D.; Mertens, S.; Miller, W.; Miloradovic, M.; Mingazheva, R.; Misiaszek, M.; Moseev, P.; Myslik, J.; Nemchenok, I.; Nilsson, T.; Nolan, P.; O'Shaughnessy, C.; Othman, G.; Panas, K.; Pandola, L.; Papp, L.; Pelczar, K.; Peterson, D.; Pettus, W.; Poon, A. W. P.; Povinec, P. P.; Pullia, A.; Quintana, X. C.; Radford, D. C.; Rager, J.; Ransom, C.; Recchia, F.; Reine, A. L.; Riboldi, S.; Rielage, K.; Rozov, S.; Rouf, N. W.; Rukhadze, E.; Rumyantseva, N.; Saakyan, R.; Sala, E.; Salamida, F.; Sandukovsky, V.; Savard, G.; Schönert, S.; Schütz, A.-K.; Schulz, O.; Schuster, M.; Schwingenheuer, B.; Selivanenko, O.; Sevda, B.; Shanks, B.; Shevchik, E.; Shirchenko, M.; Simkovic, F.; Singh, L.; Singh, V.; Skorokhvatov, M.; Smolek, K.; Smolnikov, A.; Sonay, A.; Spavorova, M.; Stekl, I.; Stukov, D.; Tedeschi, D.; Thompson, J.; Van Wechel, T.; Varner, R. L.; Vasenko, A. A.; Vasilyev, S.; Veresnikova, A.; Vetter, K.; von Sturm, K.; Vorren, K.; Wagner, M.; Wang, G.-J.; Waters, D.; Wei, W.-Z.; Wester, T.; White, B. R.; Wiesinger, C.; Wilkerson, J. F.; Willers, M.; Wiseman, C.; Wojcik, M.; Wong, H. T.; Wyenberg, J.; Xu, W.; Yakushev, E.; Yang, G.; Yu, C.-H.; Yue, Q.; Yumatov, V.; Zeman, J.; Zeng, Z.; Zhitnikov, I.; Zhu, B.; Zinatulina, D.; Zschocke, A.; Zsigmond, A. J.; Zuber, K.; Zuzel, G.

2017-10-01

The observation of neutrinoless double-beta decay (0νββ) would show that lepton number is violated, reveal that neu-trinos are Majorana particles, and provide information on neutrino mass. A discovery-capable experiment covering the inverted ordering region, with effective Majorana neutrino masses of 15 - 50 meV, will require a tonne-scale experiment with excellent energy resolution and extremely low backgrounds, at the level of ˜0.1 count /(FWHM.t.yr) in the region of the signal. The current generation 76Ge experiments GERDA and the Majorana Demonstrator, utilizing high purity Germanium detectors with an intrinsic energy resolution of 0.12%, have achieved the lowest backgrounds by over an order of magnitude in the 0νββ signal region of all 0νββ experiments. Building on this success, the LEGEND collaboration has been formed to pursue a tonne-scale 76Ge experiment. The collaboration aims to develop a phased 0νββ experimental program with discovery potential at a half-life approaching or at 1028 years, using existing resources as appropriate to expedite physics results.

Neutrinoless double-beta decay - Status of evidence and future

International Nuclear Information System (INIS)

Klapdor-Kleingrothaus, H.V.

2002-01-01

Double-beta decay is indispensable to solve the question of the neutrino mass matrix together with ν oscillation experiments. Recent analysis of the most sensitive experiment in the last eight years - the Heidelberg-Moscow experiment in Gran Sasso - yields evidence for the neutrinoless decay mode at a 97% C.L. This result is the first indication for lepton number violation and for the neutrino to be a Majorana particle. We give the present status of the analysis in these proceedings. It excludes several of the neutrino mass scenarios allowed from present neutrino oscillation experiments - essentially only degenerate and partially degenerate mass scenarios survive. To improve the present result, considerably enlarged experiments are required, such as GENIUS. A GENIUS Test Facility has just been funded and will come into operation by the end of 2002

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

Science.gov (United States)

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.

Development of segmented germanium detectors for neutrinoless double beta decay experiments

International Nuclear Information System (INIS)

Liu, Jing

2009-01-01

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 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 shape

Development of segmented germanium detectors for neutrinoless double beta decay experiments

Energy Technology Data Exchange (ETDEWEB)

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

Q values of the 76Ge and 100Mo double-beta decays

International Nuclear Information System (INIS)

Rahaman, S.; Elomaa, V.-V.; Eronen, T.; Hakala, J.; Jokinen, A.; Julin, J.; Kankainen, A.; Saastamoinen, A.; Suhonen, J.; Weber, C.; Aystoe, J.

2008-01-01

Penning trap measurements using mixed beams of 76 Ge- 76 Se and 100 Mo- 100 Ru have been utilized to determine the double-beta decay Q-values of 76 Ge and 100 Mo with uncertainties less than 200 eV. The value for 76 Ge, 2039.04(16) keV is in agreement with the published SMILETRAP value, 2039.006(50) keV. The new value for 100 Mo, 3034.40(17) keV is 30 times more precise than the previous literature value, sufficient for the ongoing neutrinoless double-beta decay searches in 100 Mo. Moreover, the precise Q-value is used to calculate the phase-space integrals and the experimental nuclear matrix element of double-beta decay

Experimental search for double beta decay of 100Mo

International Nuclear Information System (INIS)

Alston-Garnjost, M.; Dougherty, B.L.; Kenney, R.W.; Krivicich, J.M.; Tripp, R.D.; Nicholson, H.W.; Dieterle, B.D.; Leavitt, C.P.

1986-01-01

An experiment is proposed to search for double beta decay in 100 Mo using thin silicon solid state detectors. We expect to be sensitive to a half life limit of over 2 x 10 23 years for the neutrinoless mode and 2 x 10 20 years for the two-neutrino mode in one year's running. This is a substantial improvement in the measurement of the limits on electron neutrino mass and/or right-handed current admixtures over present 76 Ge experiments. 16 refs., 12 figs., 9 tabs

Double Beta Decay in Xenon-136. Measuring the Neutrino-Emitting Mode and Searching for Majoron-Emitting Modes

Energy Technology Data Exchange (ETDEWEB)

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.

A measurement of the 2 neutrino double beta decay rate of Te-130 in the CUORICINO experiment

Energy Technology Data Exchange (ETDEWEB)

Kogler, Laura K. [Univ. of California, Berkeley, CA (United States)

2011-11-30

CUORICINO was a cryogenic bolometer experiment designed to search for neutrinoless double beta decay and other rare processes, including double beta decay with two neutrinos (2vββ). The experiment was located at Laboratori Nazionali del Gran Sasso and ran for a period of about 5 years, from 2003 to 2008. The detector consisted of an array of 62 TeO₂ crystals arranged in a tower and operated at a temperature of 10 mK. Events depositing energy in the detectors, such as radioactive decays or impinging particles, produced thermal pulses in the crystals which were read out using sensitive thermistors. The experiment included 4 enriched crystals, 2 enriched with ¹³⁰Te and 2 with ¹²⁸Te, in order to aid in the measurement of the 2vββ rate. The enriched crystals contained a total of 350 g ¹³⁰Te. The 128-enriched (130-depleted) crystals were used as background monitors, so that the shared backgrounds could be subtracted from the energy spectrum of the 130- enriched crystals. Residual backgrounds in the subtracted spectrum were fit using spectra generated by Monte-Carlo simulations of natural radioactive contaminants located in and on the crystals. The 2vββ half-life was measured to be T^2v_1/2 = [9.81± 0.96(stat)± 0.49(syst)] x10²⁰ y.

Possible test of grand unification in the double beta-decay

International Nuclear Information System (INIS)

Faessler, A.

1988-01-01

The more successful grand unified theories predict that the neutrino is identical with its antiparticle and therefore is a Majorana neutrino which violates lepton number conservation. Such a neutrino should have a finite mass and also a small right handed weak interaction. If the double neutrinoless beta decay is observed with the full decay energy in the two electrons, it would establish that the electron neutrino is a Majorana particle. It is shown that the relativistic corrections of the nucleonic wave functions are essential for determining an upper limit of the right handedness from the measured lower limit of the life-time against the neutrinoless double beta decay. The upper limit for the right handedness of the weak interaction derived from the lower limit of the life-times against the neutrinoless beta decay is vertical stroke vertical stroke -8 and the upper limit for the neutrino mass is vertical stroke ν m>vertical stroke + -decay in proton rich nuclei, one can explain the long standing puzzle of the quenching of the Gamow-Teller strength in agreement with the data. (orig.)

Double Beta Decay and Neutrino Masses Accuracy of the Nuclear Matrix Elements

International Nuclear Information System (INIS)

Faessler, Amand

2005-01-01

The neutrinoless double beta decay is forbidden in the standard model of the electroweak and strong interaction but allowed in most Grand Unified Theories (GUT's). Only if the neutrino is a Majorana particle (identical with its antiparticle) and if it has a mass, the neutrinoless double beta decay is allowed. Apart of one claim that the neutrinoless double beta decay in 76 Ge is measured, one has only upper limits for this transition probability. But even the upper limits allow to give upper limits for the electron Majorana neutrino mass and upper limits for parameters of GUT's and the minimal R-parity violating supersymmetric model. One further can give lower limits for the vector boson mediating mainly the right-handed weak interaction and the heavy mainly right-handed Majorana neutrino in left-right symmetric GUT's. For that one has to assume that the specific mechanism is the leading one for the neutrinoless double beta decay and one has to be able to calculate reliably the corresponding nuclear matrix elements. In the present contribution, one discusses the accuracy of the present status of calculating the nuclear matrix elements and the corresponding limits of GUT's and supersymmetric parameters

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

Energy Technology Data Exchange (ETDEWEB)

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.

The Majorana Demonstrator: Progress towards showing the feasibility of a tonne-scale 76Ge neutrinoless double-beta decay experiment

Science.gov (United States)

Finnerty, P.; Aguayo, E.; Amman, M.; Avignone, F. T., Iii; Barabash, A. S.; Barton, P. J.; Beene, J. R.; 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.; Fraenkle, F. M.; Galindo-Uribarri, A.; Gehman, V. M.; Giovanetti, G. K.; Green, M. P.; Guiseppe, V. E.; Gusey, K.; Hallin, A. L.; Hazama, R.; Henning, R.; Hoppe, E. W.; Horton, M.; Howard, S.; Howe, M. A.; Johnson, R. A.; Keeter, K. J.; Kidd, M. F.; Knecht, A.; Kochetov, O.; Konovalov, S. I.; Kouzes, R. T.; LaFerriere, B. D.; Leon, J.; Leviner, L. E.; Loach, J. C.; Luke, P. N.; MacMullin, S.; Marino, M. G.; Martin, R. D.; Merriman, J. H.; Miller, M. L.; Mizouni, L.; Nomachi, M.; Orrell, J. L.; Overman, N. R.; Perumpilly, G.; Phillips, D. G., Ii; Poon, A. W. P.; Radford, D. C.; Rielage, K.; Robertson, R. G. H.; Ronquest, M. C.; Schubert, A. G.; Shima, T.; Shirchenko, M.; Snavely, K. J.; Steele, D.; Strain, J.; Timkin, V.; Tornow, W.; Varner, R. L.; Vetter, K.; Vorren, K.; Wilkerson, J. F.; Yakushev, E.; Yaver, H.; Young, A. R.; Yu, C.-H.; Yumatov, V.; Majorana Collaboration

2014-03-01

The Majorana Demonstrator will search for the neutrinoless double-beta decay (0vββ) 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 low-background environment and surrounded by passive and active shielding. The goals for the Demonstrator are: demonstrating a background rate less than 3 t-1 y-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 0vββ [1]; and performing a direct search for light WIMPs (3-10 GeV/c2).

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

International Nuclear Information System (INIS)

Barros, N; Thurn, J; Zuber, K

2014-01-01

The sensitivity for double beta decay studies of 134 Xe and 124 Xe is investigated assuming a potential large scale Xe experiment developed for dark matter searches depleted in 136 Xe. The opportunity for an observation of the 2νββ - decay of 134 Xe is explored for various scenarios. A positive observation should be possible for all calculated nuclear matrix elements. The detection of 2ν ECEC of 124 Xe can be probed in all scenarios covering the theoretical predicted half-life uncertainties and a potential search for 126 Xe is discussed. The sensitivity to β + EC decay of 124 Xe 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, 85 Kr beta decay and remaining 136 Xe double beta decay as background components in the depleted detector. (paper)

Facilities for studying the double beta decay processes

International Nuclear Information System (INIS)

Zdesenko, Yu.G.

1980-01-01

Modern state, tendencies and perspectiVes of the development of experimental installations to study double β-decay are treated. The main peculiarities of direct recognition and full experiments on the study of double β-decay are considered. A simple ratio is obtained from statistical considerations which connects the life time limits of the nuclei with the facility parameters to conduct direct recognition experiments. Possibilities of different detectors are evaluated on the basis of the ratio. Requirements for the modern technique for complete investigation of double β-decay are formulated and two designs of facilities meeting the requirements are considered. It is shown that the facility with proportional chambers is more perspective. On the basis of the analysis of the facility development to study double β-decay, conclusion is made that the final and unambiguous proof of the existence of double β-decay process can be obtained only directly in the experiments with immediate recording of the decay acts. Possibilities of the existing and developed facilities to conduct recognition (direct) experiments are such, that with their help life time limits as to neutronless double β-decay at the level of 10 21 -10 22 years can be established. Counters on the basis of the condensed noble gases, semiconductor detectors made of TeCd, scintillators of big volume are the most perspective detectors. To conduct complete experiments it is necessary to develop a facility with sensitivity sufficient for the detection of two-neutrino double β-activeness when Tsub(1/2)=10sup(21) years [ru

Purifications of calcium carbonate and molybdenum oxide powders for neutrinoless double beta decay experiment, AMoRE

International Nuclear Information System (INIS)

Park, HyangKyu

2015-01-01

The AMoRE (Advanced Mo based Rare process Experiment) collaboration is going to use calcium molybdate crystals to search for neutrinoless double beta decay of 100 Mo 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

Double beta decay and majorana neutrinos. Right-handed currents or nonzero masses

International Nuclear Information System (INIS)

Rosen, S.P.; Perlmutter, A.

1981-01-01

This chapter describes some new developments concerning the mechanism for lepton number nonconservation in no-neutrino double beta decay. Explains that lepton number nonconservation in no-neutrino double beta decay comes about either because both left- and right-handed components of a Majorano neutrino are coupled to the electron in the weak leptonic current, or because the neutrino has nonzero mass. Shows that while nuclear ground-state to ground-state transitions arise from right-handed currents and from neutrino mass terms, transitions to low-lying excited states with J /SUP P/ =2 + can arise only from right-handed currents. Emphasizes that the possibilities of detecting small admixtures of right-handed currents, and of setting limits on neutrino masses that are either very small or very large, make double beta decay a most rewarding phenomenon to study

Double beta decay in gauge theories

International Nuclear Information System (INIS)

Vergados, J.D.

2002-01-01

Neutrinoless double beta decay is a very important process both from the particle and nuclear physics point of view. From the elementary particle point of view it pops up in almost every model, giving rise among others to the following mechanisms: a) The traditional contributions like the light neutrino mass mechanism as well as the j L - j R leptonic interference (λ and η terms). b) The exotic R-parity violating supersymmetric (SUSY) contributions. From the nuclear physics point of view it is challenging, because: 1) The nuclei, which can undergo double beta decay, have complicated nuclear structure. 2) The energetically allowed transitions are suppressed (exhaust a small part of all the strength). 3) Since in some mechanisms the intermediate particles are very heavy one must cope with the short distance behavior of the transition operators. 4) The intermediate momenta involved are quite high and one has to consider momentum dependent terms of the nucleon current. Taking the above effects into account from the experimental limits on the interesting nuclei A=76, 82, 96, 100, 116, 128, 130, 136 and 150, we have extracted new limits on the various lepton violating parameters. In particular we get a stringent limit on the R-parity violating parameter λ' 111 -4 . (author)

Neutrinoless double beta decay and lepton flavor violation

International Nuclear Information System (INIS)

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

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→eγ and μ→e conversion in nuclei, which will be studied with high sensitivity in forthcoming experiments

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

Energy Technology Data Exchange (ETDEWEB)

Gironi, L., E-mail: luca.gironi@mib.infn.it [Università degli Studi di Milano-Bicocca, Milano (Italy); INFN – Sezione di Milano-Bicocca, Milano (Italy)

2016-07-11

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. - Highlights: • The LUCIFER technique will be the demonstrator for a higher mass experiment. • Scintillating bolometers allow high energy resolution and background discrimination. • The first choice for the LUCIFER tower are ZnSe crystals. • The LUCIFER setup will consist of an array of 30 individual single module detectors. • An array of ZnMoO4 crystals allowed the bolometric observation of the 2vDBD of {sup 100}Mo.

Simulation of double beta decay in the 'SeXe' TPC

Energy Technology Data Exchange (ETDEWEB)

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.

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

International Nuclear Information System (INIS)

Álvarez, V; Cárcel, S; Cervera, A; Díaz, J; Ferrario, P; Bandac, I; Bettini, A; Castel, J; Cebrián, S; Dafni, T; Borges, F I G M; Conde, C A N; Dias, T H V T; Fernandes, L M P; Freitas, E D C; Egorov, M; Gehman, V M; Esteve, R; Evtoukhovitch, P; Ferreira, A L

2013-01-01

The ''Neutrino Experiment with a Xenon Time-Projection Chamber'' (NEXT) is intended to investigate the neutrinoless double beta decay of 136 Xe, 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 and apos;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.

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

Energy Technology Data Exchange (ETDEWEB)

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.

Future perspectives of double beta decay and dark matter search - GENIUS

International Nuclear Information System (INIS)

Klapdor-Kleingrothaus, H.V.; Hellmig, J.; Hirsch, M.

1998-01-01

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 76 Ge or even of natural Ge making the experiment competitive with LHC in the search for supersymmetry. (author)

Neutrinoless double beta decay in Gerda

Science.gov (United States)

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.

Hamiltonian Markov Chain Monte Carlo Methods for the CUORE Neutrinoless Double Beta Decay Sensitivity

Science.gov (United States)

Graham, Eleanor; Cuore Collaboration

2017-09-01

The CUORE experiment is a large-scale bolometric detector seeking to observe the never-before-seen process of neutrinoless double beta decay. Predictions for CUORE's sensitivity to neutrinoless double beta decay allow for an understanding of the half-life ranges that the detector can probe, and also to evaluate the relative importance of different detector parameters. Currently, CUORE uses a Bayesian analysis based in BAT, which uses Metropolis-Hastings Markov Chain Monte Carlo, for its sensitivity studies. My work evaluates the viability and potential improvements of switching the Bayesian analysis to Hamiltonian Monte Carlo, realized through the program Stan and its Morpho interface. I demonstrate that the BAT study can be successfully recreated in Stan, and perform a detailed comparison between the results and computation times of the two methods.

Radon and material radiopurity assessment for the NEXT double beta decay experiment

Energy Technology Data Exchange (ETDEWEB)

Cebrián, S.; Dafni, T.; González-Díaz, D.; Herrera, D. C.; Irastorza, I. G.; Luzón, G.; Ortiz de Solórzano, A.; Villar, J. A. [Laboratorio de Física Nuclear y Astropartículas, Universidad de Zaragoza, C/ Pedro Cerbuna 12, 50009 Zaragoza (Spain); Laboratorio Subterráneo de Canfranc, Paseo de los Ayerbe s/n, 22880 Canfranc Estación, Huesca (Spain); Pérez, J. [Instituto de Física Teórica, UAM/CSIC, Campus de Cantoblanco, 28049 Madrid (Spain); Bandac, I. [Laboratorio Subterráneo de Canfranc, Paseo de los Ayerbe s/n, 22880 Canfranc Estación, Huesca (Spain); Labarga, L. [Dpto. de Física Teórica, Universidad Autónoma de Madrid, Campus de Cantoblanco, 28049 Madrid (Spain); Álvarez, V.; Cárcel, S.; Cervera, A.; Díaz, J.; Ferrario, P.; Gómez-Cadenas, J. J.; Laing, A.; Liubarsky, I.; López-March, N. [Instituto de Física Corpuscular, CSIC & Universitat de València, C/ Catedrático José Beltrán, 2, 46980 Paterna, Valencia (Spain); and others

2015-08-17

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 {sup 136}Xe 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.

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

International Nuclear Information System (INIS)

Agostini, Matteo

2013-01-01

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 214 Bi, 208 Tl and 42 K gamma-rays, with secondary contributions from 42 K and 214 Bi beta-rays, and 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.

New developments in the calculation of double beta decay

International Nuclear Information System (INIS)

Engel, J.

1990-01-01

I review recent work on computing double beta decay rates. After a discussion of shell model and Quasiparticle Random Phase calculations, I argue for a model based on the notion of generalized seniority that combines the advantages of both earlier approaches. (orig.)

Neutrinoless double beta decay in GERDA Phase II

International Nuclear Information System (INIS)

Macolino, C.

2014-01-01

The GERmanium Detector Array, GERDA, is designed to search for neutrinoless double beta (0νββ) decay of 76 Ge and it is installed in the Laboratori Nazionali del Gran Sasso (LNGS) of INFN, Italy. The GERDA experiment has completed the Phase I with a total collected exposure of 21.6 kg yr and a background index (BI) of the order of BI ≃ 10 −2 cts/(keVkg yr). No excess of events from 0νββ decay has been observed and a lower limit on the half-life on the 0νββ decay for 76 Ge has been estimated: T 0ν 1 /2 > 2.1·10 25 yr at 90% CL. The goal of GERDA Phase II is to reach the target sensitivity of T 0ν 1 /2 ≃ 1.4 · 10 26 yr, with an increased total mass of the enriched material and a reduced background level. In this paper the results from GERDA Phase I and the major improvements planned for Phase II are discussed.

Front-end electronics for accurate energy measurement of double beta decays

International Nuclear Information System (INIS)

Gil, A.; Díaz, J.; Gómez-Cadenas, J.J.; Herrero, V.; Rodriguez, J.; Serra, L.; Toledo, J.; Esteve, R.; Monzó, J.M.; Monrabal, F.; Yahlali, N.

2012-01-01

NEXT, a double beta decay experiment that will operate in Canfranc Underground Laboratory (Spain), aims at measuring the neutrinoless double-β decay of the 136Xe isotope using a TPC filled with enriched Xenon gas at high pressure operated in electroluminescence mode. One technological challenge of the experiment is to achieve resolution better than 1% in the energy measurement using a plane of UV sensitive photomultipliers readout with appropriate custom-made front-end electronics. The front-end is designed to be sensitive to the single photo-electron to detect the weak primary scintillation light produced in the chamber, and also to be able to cope with the electroluminescence signal (several hundred times higher and with a duration of microseconds). For efficient primary scintillation detection and precise energy measurement of the electroluminescent signals the front-end electronics features low noise and adequate amplification. The signal shaping provided allows the digitization of the signals at a frequency as low as 40 MHz.

Measurement of the two-neutrino double-beta decay half-life of {sup 130}Te with the CUORE-0 experiment

Energy Technology Data Exchange (ETDEWEB)

Alduino, C.; Avignone, F.T.; Chott, N.; Creswick, R.J.; Rosenfeld, C.; Wilson, J. [University of South Carolina, Department of Physics and Astronomy, Columbia, SC (United States); Alfonso, K.; Hickerson, K.P.; Huang, H.Z.; Liu, X.; Trentalange, S.; Zhu, B.X. [University of California, Department of Physics and Astronomy, Los Angeles, CA (United States); 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); Azzolini, O.; Camacho, A.; Keppel, G.; Palmieri, V.; Pira, C. [INFN-Laboratori Nazionali di Legnaro, Legnaro, Padova (Italy); Banks, T.I.; Drobizhev, A.; Freedman, S.J.; Hennings-Yeomans, R.; O' Donnell, T.; Wagaarachchi, S.L. [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. [INFN-Sezione di Bologna, Bologna (Italy); Beeman, J.W. [Lawrence Berkeley National Laboratory, Materials Science Division, Berkeley, CA (United States); Bellini, F.; Cardani, L.; Casali, N.; Cosmelli, C.; Ferroni, F. [Sapienza Universita di Roma, Dipartimento di Fisica, Rome (Italy); INFN-Sezione di Roma, Rome (Italy); Bersani, A.; Caminata, A. [INFN-Sezione di Genova, Genova (Italy); Biassoni, M.; Carbone, L.; Cremonesi, O.; Ferri, E.; Giachero, A.; Pessina, G.; Previtali, E.; Rusconi, C. [INFN-Sezione di Milano Bicocca, Milan (Italy); Brofferio, C.; Capelli, S.; Carniti, P.; Cassina, L.; Chiesa, D.; Clemenza, M.; Faverzani, M.; Fiorini, E.; Gironi, L.; Gotti, C.; Maino, M.; Nucciotti, A.; Pavan, M.; Pozzi, S.; Sisti, M.; Terranova, F.; Zanotti, L. [Universita di Milano-Bicocca, Dipartimento di Fisica, Milan (Italy); INFN-Sezione di Milano Bicocca, Milan (Italy); Bucci, C.; Cappelli, L.; D' Addabbo, A.; Di Vacri, M.L.; Gorla, P.; Pattavina, L.; Pirro, S. [INFN-Laboratori Nazionali del Gran Sasso, Assergi, L' Aquila (Italy); Canonica, L. [INFN-Laboratori Nazionali del Gran Sasso, Assergi, L' Aquila (Italy); Massachusetts Institute of Technology, Cambridge, MA (United States); Cao, X.G.; Fang, D.Q.; Ma, Y.G.; Wang, H.W.; Zhang, G.Q. [Chinese Academy of Sciences, Shanghai Institute of Applied Physics, Shanghai (China); Copello, S.; Di Domizio, S.; Fernandes, G.; Marini, L.; Pallavicini, M. [INFN-Sezione di Genova, Genova (Italy); Universita di Genova, Dipartimento di Fisica, Genova (Italy); Cushman, J.S.; Davis, C.J.; Heeger, K.M.; Lim, K.E.; Maruyama, R.H. [Yale University, Department of Physics, New Haven, CT (United States); Dafinei, I.; Morganti, S.; Mosteiro, P.J.; Orio, F.; Pettinacci, V.; Tomei, C.; Vignati, M. [INFN-Sezione di Roma, Rome (Italy); Dell' Oro, S. [INFN-Laboratori Nazionali del Gran Sasso, Assergi, L' Aquila (Italy); INFN-Gran Sasso Science Institute, L' Aquila (Italy); Feintzeig, J.; Fujikawa, B.K.; Mei, Y.; Smith, A.R. [Lawrence Berkeley National Laboratory, Nuclear Science Division, Berkeley, CA (United States); Franceschi, M.A.; Ligi, C.; Napolitano, T.; Piperno, G. [INFN-Laboratori Nazionali di Frascati, Frascati, Rome (Italy); Giuliani, A.; Tenconi, M. [Universite Paris-Saclay, CSNSM, Univ. Paris-Sud, CNRS/IN2P3, Orsay (France); Gladstone, L.; Leder, A.; Winslow, L.A. [Massachusetts Institute of Technology, Cambridge, MA (United States); 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); Han, K. [Yale University, Department of Physics, New Haven, CT (United States); Shanghai Jiao Tong University, Department of Physics and Astronomy, Shanghai (China); Hansen, E. [University of California, Department of Physics and Astronomy, Los Angeles, CA (United States); Massachusetts Institute of Technology, Cambridge, MA (United States); Kadel, R. [Lawrence Berkeley National Laboratory, Physics Division, Berkeley, CA (United States); Kolomensky, Yu.G. [University of California, Department of Physics, Berkeley, CA (United States); Lawrence Berkeley National Laboratory, Nuclear Science Division, Berkeley, CA (United States); Lawrence Berkeley National Laboratory, Physics Division, Berkeley, CA (United States); Martinez, M. [Sapienza Universita di Roma, Dipartimento di Fisica, Rome (Italy); INFN-Sezione di Roma, Rome (Italy); Universidad de Zaragoza, Laboratorio de Fisica Nuclear y Astroparticulas, Zaragoza (Spain); Moggi, N. [INFN-Sezione di Bologna, Bologna (Italy); Alma Mater Studiorum-Universita di Bologna, Dipartimento di Scienze per la Qualita della Vita, Bologna (Italy); Nones, C. [Service de Physique des Particules, CEA/Saclay, 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); Massachusetts Institute of Technology, Cambridge, MA (United States); Pagliarone, C.E. [INFN-Laboratori Nazionali del Gran Sasso, Assergi, L' Aquila (Italy); Universita degli Studi di Cassino e del Lazio Meridionale, Dipartimento di Ingegneria Civile e Meccanica, Cassino (Italy); Sangiorgio, S.; Scielzo, N.D. [Lawrence Livermore National Laboratory, Livermore, CA (United States); Santone, D. [INFN-Laboratori Nazionali del Gran Sasso, Assergi, L' Aquila (Italy); Universita dell' Aquila, Dipartimento di Scienze Fisiche e Chimiche, L' Aquila (Italy); Singh, V. [University of California, Department of Physics, Berkeley, CA (US); Taffarello, L. [INFN-Sezione di Padova, Padova (IT); Wise, T. [Yale University, Department of Physics, New Haven, CT (US); University of Wisconsin, Department of Physics, Madison, WI (US); Woodcraft, A. [University of Edinburgh, SUPA, Institute for Astronomy, Edinburgh (GB); Zimmermann, S. [Lawrence Berkeley National Laboratory, Engineering Division, Berkeley, CA (US); Zucchelli, S. [INFN-Sezione di Bologna, Bologna (IT); Alma Mater Studiorum-Universita di Bologna, Dipartimento di Fisica e Astronomia, Bologna (IT)

2017-01-15

We report on the measurement of the two-neutrino double-beta decay half-life of {sup 130}Te with the CUORE-0 detector. From an exposure of 33.4 kg year of TeO{sub 2}, the half-life is determined to be T{sub 1/2}{sup 2ν} = [8.2 ± 0.2 (stat.) ± 0.6 (syst.)] x 10{sup 20} year. This result is obtained after a detailed reconstruction of the sources responsible for the CUORE-0 counting rate, with a specific study of those contributing to the {sup 130}Te neutrinoless double-beta decay region of interest. (orig.)

Simulation of complex detection systems in neutrinoless double beta decay experiments

International Nuclear Information System (INIS)

Larrea, A.; Morales, A.; Morales, J.; Nunez-Lagos, R.; Puimedon, J.; Villar, J.A.

1988-01-01

The estimated efficiency of several detection systems dedicated to the search of the neutrinoless double beta decay of 76 Ge is reported. In order to perform this work, we have developed the GEOM macro library system which can handle highly complex geometries in simulation problems, allowing to include an accurate description of the experimental setup in a very simple way. Also an internal mechanism for checking the correct location of every boundary defining the geometrical regions is included. The present version of GEOM is implemented in the EGS4 code of Monte Carlo simulation of photons and electron/positron showers, but it can be easily extended to other simulation codes. (orig.)

Present status of radiochemical double beta decay study (238U)

International Nuclear Information System (INIS)

Madic, C.; Maillard, C.; Chevallier, A.; Chevallier, J.; Escoubes, B.; Schulz, N.; Sens, J.C.

1989-01-01

A sensitive experiment has been designed that will be able to measure an assumed half-life of 1.9x10 22 yr. This double beta corresponds to the activity of 27000 238 Pu nuclei formed during a year, in a 200 m deep mine, from 300 kg of 238 U, giving 210 alpha decays per year. Plutonium 238 et 239 will be determined by alpha spectroscopy after extraction chromatography. Experimental studies were undertaken to select the best conditions for running the extraction chromatography cycles

Analysis method for the search for neutrinoless double beta decay in the NEMO3 experiment: study of the background and first results

International Nuclear Information System (INIS)

Etienvre, A.I.

2003-04-01

The NEMO3 detector, installed in the Frejus Underground Laboratory, is dedicated to the study of neutrinoless double beta decay: the observation of this process would sign the massive and Majorana nature of neutrino. The experiment consists in very thin central source foils (the total mass is equal to 10 kg), a tracking detector made of drift cells operating in Geiger mode, a calorimeter made of plastic scintillators associated to photomultipliers, a coil producing a 30 gauss magnetic field and two shields, dedicated to the reduction of the γ-ray and neutron fluxes. In the first part, I describe the implications of several mechanisms, related to trilinear R-parity violation, on double beta decay. The second part is dedicated to a detailed study of the tracking detector of the experiment: after a description of the different working tests, I present the determination of the characteristics of the tracking reconstruction (transverse and longitudinal resolution, by Geiger cell and precision on vertex determination, charge recognition). The last part corresponds to the analysis of the data taken by the experiment. On the one hand, an upper limit on the Tl 208 activity of the sources has been determined: it is lower than 68 mBq/kg, at 90% of confidence level. On the other hand, I have developed and tested on these data a method in order to analyse the neutrinoless double beta decay signal; this method is based on a maximum of likelihood using all the available information. Using this method, I could determine a first and very preliminary upper limit on the effective mass of the neutrino. (author)

Ice shielding in the large scale GENIUS experiment for double beta decay and dark matter search

International Nuclear Information System (INIS)

Klapdor-Kleingrothaus, H.V.; Zdesenko, Yu.G.

1998-01-01

We suggest here the use of ice as shielding material in the large scale GENIUS experiment for the ultimate sensitive double beta decay and dark matter search. The idea is to pack a working volume of several tons of liquid nitrogen, which contains the ''naked'' Ge detectors, inside an ice shielding. Very thin plastic foil would be used in order to prevent leakage of the liquid nitrogen. Due to the excellent advantages of ice shielding (high purity and low cost, self-supporting ability, thermo-isolation and optical properties, safety) this could be another possible way of realization of the GENIUS project. (orig.)

Computer code for double beta decay QRPA based calculations

Energy Technology Data Exchange (ETDEWEB)

Barbero, C. A.; Mariano, A. [Departamento de Física, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina and Instituto de Física La Plata, CONICET, La Plata (Argentina); Krmpotić, F. [Instituto de Física La Plata, CONICET, La Plata, Argentina and Instituto de Física Teórica, Universidade Estadual Paulista, São Paulo (Brazil); Samana, A. R.; Ferreira, V. dos Santos [Departamento de Ciências Exatas e Tecnológicas, Universidade Estadual de Santa Cruz, BA (Brazil); Bertulani, C. A. [Department of Physics, Texas A and M University-Commerce, Commerce, TX (United States)

2014-11-11

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{sup ±} processes, is extended to include also the nuclear double beta decay.

Double beta decay in the generalized seniority scheme

International Nuclear Information System (INIS)

Pittel, S.; Engel, J.; Vogel, P.; Ji Xiangdong

1990-01-01

A generalized-seniority truncation scheme is used in shell-model calculations of double beta decay matrix elements. Calculations are carried out for 78 Ge, 82 Se and 128,130 Te. Matrix elements calculated for the two-neutrino decay mode are small compared to weak-coupling shell-model calculations and support the suppression mechanism first observed in the quasi-particle random phase approximation. Matrix elements for the neutrinoless mode are similar to those of the weak-coupling shell model, suggesting that these matrix elements can be pinned down fairly accurately. (orig.)

Results on Neutrinoless Double-β Decay of Ge76 from Phase I of the GERDA Experiment

Science.gov (United States)

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.; 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.; Janicskó Csáthy, J.; 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.; 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.

2013-09-01

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 Ge76. Data considered in the present analysis have been collected between November 2011 and May 2013 with a total exposure of 21.6 kg yr. A blind analysis is performed. The background index is about 1×10-2counts/(keVkgyr) after pulse shape discrimination. No signal is observed and a lower limit is derived for the half-life of neutrinoless double beta decay of Ge76, T1/20ν>2.1×1025yr (90% C.L.). The combination with the results from the previous experiments with Ge76 yields T1/20ν>3.0×1025yr (90% C.L.).

Weak decays and double beta decay. Annual progress report, January 1, 1982-December 31, 1982

International Nuclear Information System (INIS)

Nicholson, H.W.

1982-08-01

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

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

International Nuclear Information System (INIS)

Klapdor-Kleingrothaus, H.V.

2001-01-01

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 > 7 Be) solar neutrinos. A GENIUS Test Facility has just been funded and will come into operation by the end of 2001

Neutrino-Less Double Beta Decay - Experimentum Crucis of Neutrino Physics

International Nuclear Information System (INIS)

Sujkowski, Z.

2003-01-01

The presently most wanted information on neutrino properties concerns their mass values and their transformation properties under charge conjugation. The recent oscillation experiments prove that at least one of the three neutrino species has a non-vanishing rest mass and that the lepton flavour is not conserved. These findings have to be supplemented by data from phenomena of different kind in order to deduce the information needed. The most promising method proposed thus far to determine Majorana neutrino mass and thus to answer the two leading questions is to observe the neutrino-less double beta decay and to measure its rate. The physics of this process is discussed and the on-going and planned experimental search is reviewed. This search concentrates on the 0 + →0 + ground-to-ground state decay of β - β - emitters using calorimetric or β - -β - coincidence tracking techniques. The β + β + or β + EC decays are usually considered as less favourable because of longer half-lives, even though they offer some advantages in combating the background. The recent proposition of measuring the monoenergetic photon spectra accompanying the radiative neutrino-less double electron capture decay is discussed. The experimental advantages of this technique may off-set the generally longer life-times expected. (author)

Internal Energy Loss of the Electrons Ejected in Neutrinoless Double Beta Decay

International Nuclear Information System (INIS)

Drukarev, E. G.; Amusia, M. Ya.; Chernysheva, L. V.

2017-01-01

The excitations of the electron shell in neutrinoless double beta decay shifts the limiting energy available for ejected electrons. We present the general equations for this shift and make computations for the decays of two nuclei—germanium and xenon. (author)

The next enriched xenon observatory. A search for neutrinoless double beta decay

Energy Technology Data Exchange (ETDEWEB)

Bayerlein, Reimund; Hufschmidt, Patrick; Jamil, Ako; Schneider, Judith; Wagenpfeil, Michael; Wrede, Gerrit; Ziegler, Tobias; Hoessl, Juergen; Anton, Gisela; Michel, Thilo [ECAP, Friedrich-Alexander-Universitaet Erlangen-Nuernberg (Germany)

2016-07-01

The question whether the neutrino could be its own antiparticle is still not answered. The most practical way to test this is the search for the neutrinoless double beta decay. The half-life of this decay is related to the value of a linear combination of the masses of the neutrino mass eigenstates and therefore provides information about the absolute mass scale of neutrinos. The nEXO experiment - the successor of EXO200 - is currently under research and development. The baseline concept comprises a single-phase liquid xenon (LXe) time projection chamber (TPC) filled with about 5 tons of liquid xenon enriched to about 80% Xe-136 as the double beta decay nuclide. In order to fully cover the range of the effective Majorana neutrino mass in the inverted hierarchy scheme, excellent energy resolution is required. Therefore, a position-resolving, low-noise charge readout and very efficient light collection and detection are mandatory. For the purpose of very low background levels radiopure Silicon Photomultipliers (SiPMs) have to be used to detect the scintillation light of LXe. Due to the large half-life a huge detector mass and long term measurement are needed. In this talk the baseline-concept of the experimental setup is presented.

Exchange effects in double beta decay

International Nuclear Information System (INIS)

Stephenson, G.J. Jr.; Goldman, T.; Maltman, K.R.; Schmidt, K.E.

1988-01-01

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 130 Te, which has lead 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

Double beta decay and neutrino mass models

Energy Technology Data Exchange (ETDEWEB)

Helo, J.C. [Universidad Técnica Federico Santa María, Centro-Científico-Tecnológico de Valparaíso, Casilla 110-V, Valparaíso (Chile); Hirsch, M. [AHEP Group, Instituto de Física Corpuscular - C.S.I.C./Universitat de València, Edificio de Institutos de Paterna, Apartado 22085, E-46071 València (Spain); Ota, T. [Department of Physics, Saitama University, Shimo-Okubo 255, 338-8570 Saitama-Sakura (Japan); Santos, F.A. Pereira dos [Departamento de Física, Pontifícia Universidade Católica do Rio de Janeiro,Rua Marquês de São Vicente 225, 22451-900 Gávea, Rio de Janeiro (Brazil)

2015-05-19

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. Our discussion is general for models based on the SM group but does not cover models with an extended gauge. 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.

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

Science.gov (United States)

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.

MaGe: a Monte Carlo framework for the Gerda and Majorana double beta decay experiments

International Nuclear Information System (INIS)

Bauer, M; Belogurov, S; Chan, Yd; Descovich, M; Detwiler, J; Di Marco, M; Fujikawa, B; Franco, D; Gehman, V; Henning, R; Hudek, K; Johnson, R; Jordan, D; Kazkaz, K; Klimenko, A; Knapp, M; Kroeninger, K; Lesko, K; Liu, X; Marino, M; Mokhtarani, A; Pandola, L; Perry, M; Poon, A; Radford, D; Tomei, C; Tull, C

2006-01-01

The Gerda and Majorana projects, both searching for the neutrinoless double beta-decay of 76 Ge, are developing a joint Monte-Carlo simulation framework called MaGe. Such an approach has many benefits: the workload for the development of general tools is shared between more experts, the code is tested in more detail, and more experimental data is made available for validation

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

Energy Technology Data Exchange (ETDEWEB)

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.

The slow control system of the GERDA double beta decay experiment at Gran Sasso

International Nuclear Information System (INIS)

Brugnera, R; Garfagnini, A; Gigante, G; Hemmer, S; Zinato, D; Costa, F; Lippi, I; Michelotto, M; Ur, C

2012-01-01

GERDA is an experiment designed and built to study double beta decays of 76 Ge. It is currently in operation at the Gran Sasso underground laboratories (LNGS). A custom slow control system has been designed to monitor and control all the critical parameters for the proper functioning of the experiment. The main sub-components of the experiment (Cryostat, Clean Room, Water Tank, electronic crates and temperatures, High Voltage Systems, Radon Monitor and Source Insertion System) are constantly monitored by several distributed clients which write acquired data to a relational database (PostgreSQL). The latter allows to maintain a history of the whole experiment and, performing correlation between different and independent components, is useful to debug possible system malfunctions. The system is complemented by a Web server, a lightweight and efficient interface to the user on shifts and to the on-call experts, and by a dedicated Alarm dispatcher which distributes the errors generated by the components to the users allowing to react in short time. The whole project has been built around open source and custom software.

Search for 136Xe neutrinoless double beta decay with the Enriched Xenon Observatory (EXO)

International Nuclear Information System (INIS)

Giroux, G.

2014-01-01

The EXO collaboration is searching for the neutrinoless double beta decay of 136 Xe. Such observation would determine an absolute mass scale for the neutrinos, establish their Majorana nature, and uncover physics beyond the Standard Model. The EXO-200 detector is a single phase liquid xenon ultra low background TPC (Time Projection Chamber), with an active mass of 110 kg of 80.6% enriched xenon in the isotope 136. The detector is currently operating at the WIPP site and has been collecting data with enriched xenon since May 2011. The data collected give a lower limit for the neutrinoless double beta decay half-life of 136 Xe: T > 1.6*10 25 years at 90% C.L. The same data give a lower limit for the 2 neutrinos double beta decay of 136 Xe: T > 2.23*10 21 years that agrees with experimental values found in the literature

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

International Nuclear Information System (INIS)

Faessler, A.; Kovalenko, S.; Simkovic, F.

1998-01-01

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

The NEXT-100 experiment for neutrinoless double beta decay searches (Conceptual Design Report)

CERN Document Server

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...

Nuclear transparency and double beta decay of molybdenum 100. Annual report, February 1, 1995 - January 31, 1996

International Nuclear Information System (INIS)

Nicholson, H.W.

1995-07-01

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

Results on neutrinoless double-β decay of 76Ge from phase I of the GERDA experiment.

Science.gov (United States)

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; 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; Janicskó Csáthy, J; 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; 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

2013-09-20

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 (76)Ge. Data considered in the present analysis have been collected between November 2011 and May 2013 with a total exposure of 21.6 kg yr. A blind analysis is performed. The background index is about 1 × 10(-2) counts/(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 (76)Ge, T(1/2)(0ν) >2.1 × 10(25) yr (90% C.L.). The combination with the results from the previous experiments with (76)Ge yields T(1/2)(0ν)>3.0 × 10(25) yr (90% C.L.).

Double-beta decay with majoron emission in GERDA Phase I

Science.gov (United States)

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.

LUCIFER: Scintillating bolometers for the search of Neutrinoless Double Beta Decay

Energy Technology Data Exchange (ETDEWEB)

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.

In-trap decay spectroscopy for {beta}{beta} decays

Energy Technology Data Exchange (ETDEWEB)

Brunner, Thomas

2011-01-18

detectors, for the detection of X-rays, were tested and installed. Several {beta} detectors were tested and mounted on especially designed holders. The feasibility of the in-trap decay spectroscopy technique has been demonstrated by successfully measuring the EC branching ratios of {sup 107}In and {sup 124}Cs. In the latter case, {sup 126}Cs was measured at the same time as {sup 124}Cs and used to calibrate the detection efficiency of the x-ray detector. During this measurement, up to 2.65(32) .10{sup 5} ions/bunch were stored in the trap while their decays were observed. Based on this measurement, the ECBR of {sup 124}Cs was determined to be (17.8{+-}2.5(stat.){+-}15(syst.))%. The large systematic uncertainty arises from an impedance mismatch between preamplifier and x-ray detector that was discovered after the experiment. Nevertheless, the new value agrees with the literature value of 10(9)% [NND10] and the statistical error was reduced by a factor of three. These measurements demonstrated the feasibility of this new method of in-trap decay spectroscopy. It was for the first time that an electron capture decay was observed of ions stored in a Penning trap. In the future, this technique will be applied to perform ECBR measurements of transition nuclei in double beta decays. (orig.)

Search for neutrinoless double beta decay with GERDA phase II

Science.gov (United States)

Agostini, M.; Bakalyarov, A. M.; Balata, M.; Barabanov, I.; Baudis, L.; Bauer, C.; Bellotti, E.; Belogurov, S.; Bettini, A.; Bezrukov, L.; Bode, T.; Borowicz, D.; Brudanin, V.; Brugnera, R.; Caldwell, A.; Cattadori, C.; Chernogorov, A.; D'Andrea, V.; Demidova, E. V.; Di Marco, N.; Domula, A.; Doroshkevich, E.; Egorov, V.; Falkenstein, R.; Gangapshev, A.; Garfagnini, A.; Gooch, C.; Grabmayr, P.; Gurentsov, V.; Gusev, K.; Hakenmüller, J.; Hegai, A.; Heisel, M.; Hemmer, S.; Hofmann, W.; Hult, M.; Inzhechik, L. V.; Csáthy, J. Janicskó; Jochum, J.; Junker, M.; Kazalov, V.; Kihm, T.; Kirpichnikov, I. V.; Kirsch, A.; Kish, A.; Klimenko, A.; Kneißl, R.; Knies, J.; Knöpfle, K. T.; Kochetov, O.; Kornoukhov, V. N.; Kuzminov, V. V.; Laubenstein, M.; Lazzaro, A.; Lebedev, V. I.; Liao, H. Y.; Lindner, M.; Lippi, I.; Lubashevskiy, A.; Lubsandorzhiev, B.; Lutter, G.; Majorovits, B.; Maneschg, W.; Marissens, G.; Miloradovic, M.; Mingazheva, R.; Misiaszek, M.; Moseev, P.; Nemchenok, I.; Panas, K.; Pandola, L.; Pelczar, K.; Pullia, A.; Ransom, C.; Reissfelder, M.; Riboldi, S.; Rumyantseva, N.; Sada, C.; Salamida, F.; Schmitt, C.; Schneider, B.; Schönert, S.; Schreiner, J.; Schulz, O.; Schütz, A.-K.; Schwingenheuer, B.; Seitz, H.; Selivanenko, O.; Shevchik, E.; Shirchenko, M.; Simgen, H.; Smolnikov, A.; Stanco, L.; Vanhoefer, L.; Vasenko, A. A.; Veresnikova, A.; von Sturm, K.; Wagner, V.; Wegmann, A.; Wester, T.; Wiesinger, C.; Wojcik, M.; Yanovich, E.; Zhitnikov, I.; Zhukov, S. V.; Zinatulina, D.; Zuber, K.; Zuzel, G.

2017-10-01

The GERmanium Detector Array (gerda) experiment, located at the Gran Sasso underground laboratory in Italy, is one of the leading experiments for the search of 0νββ decay. In Phase II of the experiment 35.6 kg of enriched germanium detectors are operated. The application of active background rejection methods, such as a liquid argon scintillation light read-out and pulse shape discrimination of germanium detector signals, allowed to reduce the background index to the intended level of 10-3 cts/(keV.kg.yr). In the first five month of data taking 10.8 kg yr of exposure were accumulated. No signal has been found and together with data from Phase I a new limit for the neutrinoless double beta decay half-life of 76Ge of 5.3 . 1025 yr at 90% C.L. was established in June 2016. Phase II data taking is ongoing and will allow the exploration of half-lifes in the 1026 yr regime. The current status of data taking and an update on the background index are presented.

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

Science.gov (United States)

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.

The Gerda experiment for the search of 0{nu}{beta}{beta} decay in {sup 76}Ge

Energy Technology Data Exchange (ETDEWEB)

Ackermann, K.H.; Altmann, M.; Becerici-Schmidt, N.; Caldwell, A.; Cossavella, F.; Lenz, D.; Liao, H.; Majorovits, B.; Mayer, S.; O' Shaughnessy, C.; Schubert, J.; Schulz, O.; Seitz, H.; Stelzer, F.; Vogt, S.; Volynets, O. [Max-Planck-Institut fuer Physik, Muenchen (Germany); Agostini, M.; Bode, T.; Budjas, D.; Janicsko Csathy, J.; Lazzaro, A.; Schoenert, S. [Technische Universitaet Muenchen, Physik Department and Excellence Cluster Universe, Munich (Germany); Allardt, M.; Barros, N.; Domula, A.; Lehnert, B.; Zuber, K. [Technische Universitaet Dresden, Institut fuer Kern- und Teilchenphysik, Dresden (Germany); Andreotti, E. [Institute for Reference Materials and Measurements, Geel (Belgium); Eberhard Karls Universitaet Tuebingen, Physikalisches Institut, Tuebingen (Germany); Bakalyarov, A.M.; Belyaev, S.T.; Lebedev, V.I.; Zhukov, S.V. [National Research Centre ' ' Kurchatov Institute' ' , Moscow (Russian Federation); Balata, M.; Ioannucci, L.; Junker, M.; Laubenstein, M.; Nisi, S.; Pandola, L. [LNGS, INFN Laboratori Nazionali del Gran Sasso, Assergi (Italy); Barabanov, I.; Bezrukov, L.; Denisov, A.; Gurentsov, V.; Kianovsky, S.; Kusminov, V.; Lubsandorzhiev, B.; Yanovich, E. [Institute for Nuclear Research of the Russian Academy of Sciences, Moscow (Russian Federation); Barnabe Heider, M. [Max Planck Institut fuer Kernphysik, Heidelberg (Germany); Technische Universitaet Muenchen, Physik Department and Excellence Cluster Universe, Munich (Germany); CEGEP St-Hyacinthe, Quebec (Canada); Baudis, L.; Benato, G.; Ferella, A.; Froborg, F.; Guthikonda, K.K.; Tarka, M.; Walter, M. [Physik Institut der Universitaet Zuerich, Zuerich (Switzerland); Bauer, C.; Hampel, W.; Heisel, M.; Heusser, G.; Hofmann, W.; Kankanyan, R.; Kihm, T.; Kiko, J.; Kirsch, A.; Knoepfle, K.T.; Lindner, M.; Lubashevskiy, A.; Machado, A.A.; Maneschg, W.; Oehm, J.; Salathe, M.; Schreiner, J.; Schwan, U.; Schwingenheuer, B.; Simgen, H.; Smolnikov, A.; Strecker, H.; Wagner, V.; Wegmann, A. [Max Planck Institut fuer Kernphysik, Heidelberg (Germany); Bellotti, E. [Universita Milano Bicocca, Dipartimento di Fisica, Milano (Italy); INFN Milano Bicocca, Milano (Italy); Belogurov, S.; Kornoukhov, V.N. [Institute for Nuclear Research of the Russian Academy of Sciences, Moscow (Russian Federation); Institute for Theoretical and Experimental Physics, Moscow (Russian Federation); Bettini, A.; Brugnera, R.; Garfagnini, A.; Hemmer, S.; Sada, C. [Dipartimento di Fisica e Astronomia dell' Universita di Padova, Padova (Italy); INFN Padova, Padova (Italy); Brudanin, V.; Egorov, V.; Kochetov, O.; Nemchenok, I.; Shevchik, E.; Zhitnikov, I.; Zinatulina, D. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Cattadori, C. [INFN Milano Bicocca, Milano (Italy); Chernogorov, A.; Demidova, E.V.; Kirpichnikov, I.V.; Vasenko, A.A. [Institute for Theoretical and Experimental Physics, Moscow (Russian Federation); Chkvorets, O. [Max Planck Institut fuer Kernphysik, Heidelberg (Germany); Laurentian University, Sudbury (Canada); D' Andragora, A. [LNGS, INFN Laboratori Nazionali del Gran Sasso, Assergi (Italy); Brookhaven National Laboratory, Upton, NY (United States); Di Vacri, A. [LNGS, INFN Laboratori Nazionali del Gran Sasso, Assergi (Italy); University ' ' G. d' Annunzio' ' di Chieti-Pescara, Department of Neurosciences and Imaging, Chieti (Italy); Falkenstein, R.; Freund, K.; Grabmayr, P.; Hegai, A.; Jochum, J.; Knapp, M.; Niedermeier, L.; Schmitt, C.; Sturm, K. von [Eberhard Karls Universitaet Tuebingen, Physikalisches Institut, Tuebingen (Germany); Frodyma, N.; Pelczar, K.; Wojcik, M.; Zuzel, G. [Jagiellonian University, Institute of Physics, Cracow (Poland); Gangapshev, A. [Max Planck Institut fuer Kernphysik, Heidelberg (Germany); Institute for Nuclear Research of the Russian Academy of Sciences, Moscow (Russian Federation); Gasparro, J. [Institute for Reference Materials and Measurements, Geel (Belgium); National Physical Laboratory, Teddigton (United Kingdom); Gazzana, S. [LNGS, INFN Laboratori Nazionali del Gran Sasso, Assergi (Italy); Max Planck Institut fuer Kernphysik, Heidelberg (Germany); Gonzalez de Orduna, R.; Hult, M.; Marissens, G. [Institute for Reference Materials and Measurements, Geel (Belgium); Gusev, K. [Joint Institute for Nuclear Research, Dubna (Russian Federation); National Research Centre ' ' Kurchatov Institute' ' , Moscow (Russian Federation); Technische Universitaet Muenchen, Physik Department and Excellence Cluster Universe, Munich (Germany); Inzhechik, L.V. [Institute for Nuclear Research of the Russian Academy of Sciences, Moscow (Russian Federation); Moscow Institute of Physics and Technology, Moscow (Russian Federation); Klimenko, A. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Max Planck Institut fuer Kernphysik, Heidelberg (Germany); Institute for Nuclear Research of the Russian Academy of Sciences, Moscow (Russian Federation); Kroeninger, K. [Max-Planck-Institut fuer Physik, Muenchen (Germany); U. Goettingen, II. Physikalisches Institut, Goettingen (Germany); U. Siegen, Department Physik, Siegen (Germany); Lippi, I.; Rossi Alvarez, C.; Stanco, L.; Ur, C.A. [INFN Padova, Padova (Italy); Liu, J. [Max-Planck-Institut fuer Physik, Muenchen (Germany); University of Tokyo, Kavli IPMU, Tokyo (Japan); Liu, X. [Shanghai Jiaotong University, Shanghai (China); Meierhofer, G. [Eberhard Karls Universitaet Tuebingen, Physikalisches Institut, Tuebingen (Germany); TUeV-SUeD, Muenchen (Germany); Peiffer, P. [Max Planck Institut fuer Kernphysik, Heidelberg (Germany); Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany); Pullia, A.; Riboldi, S. [Universita degli Studi di Milano (Italy); INFN Milano, Dipartimento di Fisica, Milano (Italy); Ritter, F. [Eberhard Karls Universitaet Tuebingen, Physikalisches Institut, Tuebingen (Germany); Robert Bosch GmbH, Reutlingen (Germany); Shirchenko, M. [Joint Institute for Nuclear Research, Dubna (Russian Federation); National Research Centre ' ' Kurchatov Institute' ' , Moscow (Russian Federation); Trunk, U. [Max Planck Institut fuer Kernphysik, Heidelberg (Germany); DESY, Photon-Science Detector Group, Hamburg (Germany); Zavarise, P. [LNGS, INFN Laboratori Nazionali del Gran Sasso, Assergi (Italy); University of L' Aquila, Dipartimento di Fisica, L' Aquila (Italy)

2013-03-15

The Gerda collaboration is performing a search for neutrinoless double beta decay of {sup 76}Ge with the eponymous detector. The experiment has been installed and commissioned at the Laboratori Nazionali del Gran Sasso and has started operation in November 2011. The design, construction and first operational results are described, along with detailed information from the R and D phase. (orig.)

Results on neutrinoless double beta decay from GERDA phase I

CERN Multimedia

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.

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

International Nuclear Information System (INIS)

Sangiorgio, S.; Artusa, D.R.; And others

2006-01-01

CUORE is a ∼ I-ton experiment to search for Neutrinoless Double Beta Decay of 130 Te using 988 TeO 2 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

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

Science.gov (United States)

Sisti, M.; 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.; 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.

2016-04-01

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 ṡkg ṡy) will be reached, in five years of data taking CUORE will have a 1σ half life sensitivity of 1026 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.

Double beta decay: a new formalism

International Nuclear Information System (INIS)

Hirsch, J.; Krmpotic, F.

1990-01-01

A study is made of the validity of those methods consisting in an average of solutions from initial and final solutions within the quasi-particle random phase approximation (QRPA) for double beta decay. A new method is developed that works with a single QRPA equation for the intermediate nucleus in which the correlations of the ground state for β - transitions are β + and vice versa. Numerical results agree in the different formulations, which avails the known averaging procedures while showing the greater operative simplicity of the proposed method for the case of the two neutrino mode in which the diagonalization process may be substituted by a matrix inversion. (Author). 13 refs., 1 fig., 1 tab

Radiopurity assessment of the energy readout for the NEXT double beta decay experiment

Science.gov (United States)

Cebrián, S.; Pérez, J.; Bandac, I.; Labarga, L.; Álvarez, V.; Azevedo, C. D. R.; Benlloch-Rodríguez, J. M.; Borges, F. I. G. M.; Botas, A.; Cárcel, S.; Carrión, J. V.; Conde, C. A. N.; Díaz, J.; Diesburg, M.; Escada, J.; Esteve, R.; Felkai, R.; Fernandes, L. M. P.; Ferrario, P.; Ferreira, A. L.; Freitas, E. D. C.; Goldschmidt, A.; Gómez-Cadenas, J. J.; González-Díaz, D.; Gutiérrez, R. M.; Hauptman, J.; Henriques, C. A. O.; Hernandez, A. I.; Hernando Morata, J. A.; Herrero, V.; Jones, B. J. P.; Laing, A.; Lebrun, P.; Liubarsky, I.; López-March, N.; Losada, M.; Martín-Albo, J.; Martínez-Lema, G.; Martínez, A.; McDonald, A. D.; Monrabal, F.; Monteiro, C. M. B.; Mora, F. J.; Moutinho, L. M.; Muñoz Vidal, J.; Musti, M.; Nebot-Guinot, M.; Novella, P.; Nygren, D. R.; Palmeiro, B.; Para, A.; Querol, M.; Renner, J.; Ripoll, L.; Rodríguez, J.; Rogers, L.; Santos, F. P.; dos Santos, J. M. F.; Simón, 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.

2017-08-01

The "Neutrino Experiment with a Xenon Time-Projection Chamber" (NEXT) experiment intends to investigate the neutrinoless double beta decay of 136Xe, and therefore requires a severe suppression of potential backgrounds. An extensive material screening and selection process was undertaken to quantify the radioactivity of the materials used in the experiment. Separate energy and tracking readout planes using different sensors allow us to combine the measurement of the topological signature of the event for background discrimination with the energy resolution optimization. The design of radiopure readout planes, in direct contact with the gas detector medium, was especially challenging since the required components typically have activities too large for experiments demanding ultra-low background conditions. After studying the tracking plane, here the radiopurity control of the energy plane is presented, mainly based on gamma-ray spectroscopy using ultra-low background germanium detectors at the Laboratorio Subterr&aposaneo de Canfranc (Spain). All the available units of the selected model of photomultiplier have been screened together with most of the components for the bases, enclosures and windows. According to these results for the activity of the relevant radioisotopes, the selected components of the energy plane would give a contribution to the overall background level in the region of interest of at most 2.4×10-4 counts keV-1 kg-1 y-1, satisfying the sensitivity requirements of the NEXT experiment.

Development of {sup 100}Mo-containing scintillating bolometers for a high-sensitivity neutrinoless double-beta decay search

Energy Technology Data Exchange (ETDEWEB)

Armengaud, E.; Gros, M.; Herve, S.; Magnier, P.; Navick, X.F.; Nones, C.; Paul, B.; Penichot, Y.; Zolotarova, A.S. [Universite Paris-Saclay, IRFU, CEA, Gif-sur-Yvette (France); Augier, C.; Billard, J.; Cazes, A.; Charlieux, F.; Jesus, M. de; Gascon, J.; Juillard, A.; Queguiner, E.; Sanglard, V.; Vagneron, L. [Univ Lyon, Universite Lyon 1, CNRS/IN2P3, IPN-Lyon, Villeurbanne (France); Barabash, A.S.; Konovalov, S.I.; Umatov, V.I. [National Research Centre Kurchatov Institute, Institute of Theoretical and Experimental Physics, Moscow (Russian Federation); Beeman, J.W. [Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Bekker, T.B. [V.S. Sobolev Institute of Geology and Mineralogy of the Siberian Branch of the RAS, Novosibirsk (Russian Federation); Bellini, F.; Ferroni, F. [Sapienza Universita di Roma, Dipartimento di Fisica, Rome (Italy); INFN, Sezione di Roma, Rome (Italy); Benoit, A.; Camus, P. [CNRS-Neel, Grenoble (France); Berge, L.; Chapellier, M.; Dumoulin, L.; Humbert, V.; Le Sueur, H.; Marcillac, P. de; Marnieros, S.; Marrache-Kikuchi, C.; Novati, V.; Olivieri, E.; Plantevin, O. [CSNSM, Univ. Paris-Sud, CNRS/IN2P3, Universite Paris-Saclay, Orsay (France); Bergmann, T.; Kleifges, M.; Tcherniakhovski, D.; Weber, M. [Karlsruhe Institute of Technology, Institut fuer Prozessdatenverarbeitung und Elektronik, Karlsruhe (Germany); Boiko, R.S.; Danevich, F.A.; Kobychev, V.V.; Nikolaichuk, M.O.; Tretyak, V.I. [Institute for Nuclear Research, Kyiv (Ukraine); Broniatowski, A. [CSNSM, Univ. Paris-Sud, CNRS/IN2P3, Universite Paris-Saclay, Orsay (France); Karlsruhe Institute of Technology, Institut fuer Experimentelle Teilchenphysik, Karlsruhe (Germany); Brudanin, V.; Rozov, S.; Yakushev, E. [JINR, Laboratory of Nuclear Problems, Dubna, Moscow Region (Russian Federation); Capelli, S.; Gironi, L.; Pavan, M.; Pessina, G. [Universita di Milano Bicocca, Dipartimento di Fisica, Milan (Italy); INFN, Sezione di Milano Bicocca, Milan (Italy); Cardani, L.; Casali, N.; Dafinei, I.; Tomei, C.; Vignati, M. [INFN, Sezione di Roma, Rome (Italy); Chernyak, D.M. [Institute for Nuclear Research, Kyiv (Ukraine); The University of Tokyo, Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo Institutes for Advanced Study, Kashiwa, Chiba (Japan); Combarieu, M. de; Pari, P. [Universite Paris-Saclay, IRAMIS, CEA, Gif-sur-Yvette (France); Coron, N.; Redon, T. [Universite Paris-Sud, IAS, CNRS, Orsay (France); Devoyon, L.; Koskas, F.; Strazzer, O. [Universite Paris-Saclay, Orphee, CEA, Gif-sur-Yvette (France); Di Domizio, S. [Universita di Genova, Dipartimento di Fisica, Genoa (Italy); INFN Sezione di Genova, Genoa (Italy); Eitel, K.; Siebenborn, B. [Karlsruhe Institute of Technology, Institut fuer Kernphysik, Karlsruhe (Germany); Enss, C.; Fleischmann, A.; Gastaldo, L. [Heidelberg University, Kirchhoff Institute for Physics, Heidelberg (Germany); Foerster, N.; Kozlov, V. [Karlsruhe Institute of Technology, Institut fuer Experimentelle Teilchenphysik, Karlsruhe (Germany); Giuliani, A. [CSNSM, Univ. Paris-Sud, CNRS/IN2P3, Universite Paris-Saclay, Orsay (France); Universita dell' Insubria, DISAT, Como (Italy); Grigorieva, V.D.; Ivannikova, N.V.; Ivanov, I.M.; Makarov, E.P.; Shlegel, V.N.; Vasiliev, Ya.V. [Nikolaev Institute of Inorganic Chemistry, Novosibirsk (Russian Federation); Hehn, L. [Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Karlsruhe Institute of Technology, Institut fuer Kernphysik, Karlsruhe (Germany); Jin, Y. [Laboratoire de Photonique et de Nanostructures, CNRS, Marcoussis (France); Kraus, H. [University of Oxford, Department of Physics, Oxford (United Kingdom); Kudryavtsev, V.A. [University of Sheffield, Department of Physics and Astronomy, Sheffield (United Kingdom); Laubenstein, M.; Nagorny, S.; Pattavina, L.; Pirro, S. [INFN, Laboratori Nazionali del Gran Sasso, Assergi, AQ (Italy); Loidl, M.; Rodrigues, M. [CEA-Saclay, CEA, LIST, Laboratoire National Henri Becquerel (LNE-LNHB), Gif-sur-Yvette Cedex (France); Mancuso, M. [CSNSM, Univ. Paris-Sud, CNRS/IN2P3, Universite Paris-Saclay, Orsay (France); Universita dell' Insubria, DISAT, Como (Italy); Max-Planck-Institut fuer Physik, Munich (Germany); Pagnanini, L.; Schaeffner, K. [INFN, Laboratori Nazionali del Gran Sasso, Assergi, AQ (Italy); INFN, Gran Sasso Science Institute, L' Aquila (Italy); Piperno, G. [INFN, Laboratori Nazionali di Frascati, Rome (Italy); Poda, D.V. [CSNSM, Univ. Paris-Sud, CNRS/IN2P3, Universite Paris-Saclay, Orsay (France); Institute for Nuclear Research, Kyiv (Ukraine); Rusconi, C. [INFN, Laboratori Nazionali del Gran Sasso, Assergi, AQ (Italy); University of South Carolina, Department of Physics and Astronomy, Columbia, SC (United States); Scorza, S. [Karlsruhe Institute of Technology, Institut fuer Experimentelle Teilchenphysik, Karlsruhe (Germany); SNOLAB, Lively, ON (Canada); Velazquez, M. [Universite de Bordeaux, ICMCB, CNRS, Pessac (France)

2017-11-15

This paper reports on the development of a technology involving {sup 100}Mo-enriched scintillating bolometers, compatible with the goals of CUPID, a proposed next-generation bolometric experiment to search for neutrinoless double-beta decay. Large mass (∝ 1 kg), high optical quality, radiopure {sup 100}Mo-containing zinc and lithium molybdate crystals have been produced and used to develop high performance single detector modules based on 0.2-0.4 kg scintillating bolometers. In particular, the energy resolution of the lithium molybdate detectors near the Q-value of the double-beta transition of {sup 100}Mo (3034 keV) is 4-6 keV FWHM. The rejection of the α-induced dominant background above 2.6 MeV is better than 8σ. Less than 10 μBq/kg activity of {sup 232}Th({sup 228}Th) and {sup 226}Ra in the crystals is ensured by boule recrystallization. The potential of {sup 100}Mo-enriched scintillating bolometers to perform high sensitivity double-beta decay searches has been demonstrated with only 10 kg x d exposure: the two neutrino double-beta decay half-life of {sup 100}Mo has been measured with the up-to-date highest accuracy as T{sub 1/2} = [6.90 ± 0.15(stat.) ± 0.37(syst.)] x 10{sup 18} years. Both crystallization and detector technologies favor lithium molybdate, which has been selected for the ongoing construction of the CUPID-0/Mo demonstrator, containing several kg of {sup 100}Mo. (orig.)

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

International Nuclear Information System (INIS)

Palioselitis, Dimitrios

2015-01-01

The Germanium Detector Array (GERDA) experiment is searching for the neutrinoless double beta (0νββ) decay of 76 Ge 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 T 0ν 1/2 > 2.1 · 10 25 yr(90% C.L.) is derived for the half life of the 0νββ decay of 76 Ge. (paper)

Limit on Neutrinoless Double Beta Decay of 76Ge by GERDA

Science.gov (United States)

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.

Double Beta Decay with Ge-detectors - and the future of Double Beta and Dark Matter Search (GENIUS)

International Nuclear Information System (INIS)

Klapdor-Kleingrothaus, H.V.

1999-01-01

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, using enriched 76 Ge - probes the electron neutrino 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

Schematic model studies of double beta decay processes

International Nuclear Information System (INIS)

Civitarese, O.

1996-01-01

Some features of the nuclear matrix elements, for double beta decay transitions to a final ground state and to a final excited one and two-quadrupole phonon states, are presented and discussed in the framework of a schematic model. The competition between spin-flip and non-spin-flip transitions on the relevant nuclear matrix elements, the effects due to proton-neutron pairing correlations and the effects due to the inclusion of exchange terms in the QRPA matrix are discussed. (Author)

Radon-induced surface contaminations in neutrinoless double beta decay and dark matter experiments

International Nuclear Information System (INIS)

Pattavina, L.

2011-01-01

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 222 Rn, radioactive daughter isotope from the 238 U chain. (author)

Results of a search for neutrinoless double-beta decay using the COBRA demonstrator

Energy Technology Data Exchange (ETDEWEB)

Quante, Thomas; Goessling, Claus; Kroeninger, Kevin [TU Dortmund, Exp. Physik IV, Dortmund (Germany)

2016-07-01

COBRA is an experiment aiming to search for neutrinoless double-beta-decay (0νββ-decay) using CdZnTe semiconductor detectors. The main focus is on {sup 116}Cd, with a Q-value of 2813.5 keV well above the highest dominant naturally occurring gamma lines. By measuring the half-life of the 0νββ-decay, it is possible to clarify the nature of the neutrino as either Dirac or Majorana particle and furthermore to determine its effective Majorana mass. The COBRA collaboration operates a demonstrator to search for these decays at the Laboratori Nazionali del Gran Sasso in Italy. The exposure of 234.7 kg d considered in this analysis was collected between September 2011 and February 2015. The analysis focuses on the decay of the nuclides {sup 114}Cd, {sup 128}Te, {sup 70}Zn, {sup 130}Te and {sup 116}Cd. A Bayesian analysis is performed to estimate the signal strength of 0νββ-decay.

Double beta decay: introduction, motivations and last results

International Nuclear Information System (INIS)

Hubert, P.

1986-01-01

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 [fr

Results on Neutrinoless Double-Beta Decay from Gerda Phase I

Science.gov (United States)

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.

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

Energy Technology Data Exchange (ETDEWEB)

Klapdor-Kleingrothaus, H.V.

1998-08-01

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 {proportional_to}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 {beta}{beta} 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.)

Neutrinoless double beta decay with 82SeF6 and direct ion imaging

Science.gov (United States)

Nygren, D. R.; Jones, B. J. P.; López-March, N.; Mei, Y.; Psihas, F.; Renner, J.

2018-03-01

We present a new neutrinoless double beta decay concept: the high pressure selenium hexafluoride gas time projection chamber. A promising new detection technique is outlined which combines techniques pioneered in high pressure xenon gas, such as topological discrimination, with the high Q-value afforded by the double beta decay isotope 82Se. The lack of free electrons in SeF6 mandates the use of an ion TPC. The microphysics of ion production and drift, which have many nuances, are explored. Background estimates are presented, suggesting that such a detector may achieve background indices of better than 1 count per ton per year in the region of interest at the 100 kg scale, and still better at the ton-scale.

Testing Left-Right extensions of the standard model of electroweak interactions with double-beta decay and LHC measurements

Science.gov (United States)

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.

Double beta decay, neutrino physics, nuclear structure and isospin and spin-isospin symmetries

International Nuclear Information System (INIS)

Krmpotic, F.

1989-12-01

Prominent features of the double beta decay processes are reviewed. Emphasis is placed on the neutrino masses and the quasiparticle random phase approximation (GRPA). The suppression mechanism for the ββ-decay transition rates, proposed by Vogel and Zirnbauer, is found to be closely related to the restoration of SU(4) symmetry. It is suggested that the extreme sensitivity of the ββ-decay amplitude on the proton-neutron coupling is a consequence of the explicit violation of the SU(4) symmetry and therefore an artifact of the model. A prescription is given for fixing this interaction strength within the GRPA itself, which in this way acquires predicting power on both single and double β-decay lifetimes. (author) [pt

New limit for the half-life of double beta decay of {sup 94}Zr to the first excited state of {sup 94}Mo

Energy Technology Data Exchange (ETDEWEB)

Dokania, N.; Nanal, V.; Gupta, G.; Pillay, R.G.; Ghosh, C. [Tata Institute of Fundamental Research, Department of Nuclear and Atomic Physics, Mumbai (India); Pal, S. [Tata Institute of Fundamental Research, Pelletron Linac Facility, Mumbai (India); Rath, P.K. [University of Lucknow, Department of Physics, Lucknow (India); Tretyak, V.I. [Institute for Nuclear Research, Kyiv (Ukraine); Garai, A.; Krishnamoorthy, H. [Tata Institute of Fundamental Research, India-based Neutrino Observatory, Mumbai (India); Homi Bhabha National Institute, Mumbai (India); Raina, P.K. [Indian Institute of Technology, Department of Physics, Rupnagar (India); Bhushan, K.G. [Bhabha Atomic Research Centre, Technical Physics Division, Mumbai (India)

2017-04-15

Neutrinoless double beta decay is a phenomenon of fundamental interest in particle physics. The decay rates of double beta decay transitions to the excited states can provide input for Nuclear Transition Matrix Element calculations for the relevant two neutrino double beta decay process. It can be useful as supplementary information for the calculation of Nuclear Transition Matrix Element for the neutrinoless double beta decay process. In the present work, double beta decay of {sup 94}Zr to the 2{sup +}{sub 1} excited state of {sup 94}Mo at 871.1 keV is studied using a low background ∝ 230 cm{sup 3} HPGe detector. No evidence of this decay was found with a 232 g.y exposure of natural zirconium. The lower half-life limit obtained for the double beta decay of {sup 94}Zr to the 2{sup +}{sub 1} excited state of {sup 94}Mo is T{sub 1/2}(0ν + 2ν) > 3.4 x 10{sup 19} y at 90% C.L., an improvement by a factor of ∝ 4 over the existing experimental limit at 90% C.L. The sensitivity is estimated to be T{sub 1/2} (0ν + 2ν) > 2.0 x 10{sup 19} y at 90% C.L. using the Feldman-Cousins method. (orig.)

Project for detecting the double beta decay of 136Xe

International Nuclear Information System (INIS)

Miyajima, M.; Sasaki, S.; Tawara, H.

1992-01-01

For detecting the nuclear double beta decay of 136 Xe, a liquid-xenon positive-ion collector and a time-of-flight mass spectrometer are under development for detecting the decay product 136 Ba. Two sets of lasers are used with the mass spectrometer. An Nd-YAG laser is used for sampling 136 Ba from the surface of the positive-ion collector electrode, and a dye laser pumped by an Nd-YAG laser is used for the selective ionization of 136 Ba. The principle of measurements as well as the experimental apparatus and procedures are described in detail, together with our future plans. (orig.)

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

Directory of Open Access Journals (Sweden)

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.

Improved limits on beta(-) and beta(-) decays of Ca-48

Czech Academy of Sciences Publication Activity Database

Bakalyarov, A.; Balysh, A.; Barabash, AS.; Beneš, P.; Briancon, C.; Brudanin, V. B.; Čermák, P.; Egorov, V.; Hubert, F.; Hubert, P.; Korolev, NA.; Kosjakov, VN.; Kovalík, Alojz; Lebedev, NA.; Novgorodov, A. F.; Rukhadze, NI.; Štekl, NI.; Timkin, VV.; Veleshko, IE.; Vylov, T.; Umatov, VI.

2002-01-01

Roč. 76, č. 9 (2002), s. 545-547 ISSN 0021-3640 Institutional research plan: CEZ:AV0Z1048901 Keywords : beta decay * double beta decay * Ca-48 Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.483, year: 2002

Analysis method for the search for neutrinoless double beta decay in the NEMO3 experiment: study of the background and first results; Methode d'analyse pour la recherche de la double desintegration {beta} sans emission de neutrinos dans l'experience NEMO3. Etude du bruit de fond et premiers resultats

Energy Technology Data Exchange (ETDEWEB)

Etienvre, A I

2003-04-15

The NEMO3 detector, installed in the Frejus Underground Laboratory, is dedicated to the study of neutrinoless double beta decay: the observation of this process would sign the massive and Majorana nature of neutrino. The experiment consists in very thin central source foils (the total mass is equal to 10 kg), a tracking detector made of drift cells operating in Geiger mode, a calorimeter made of plastic scintillators associated to photomultipliers, a coil producing a 30 gauss magnetic field and two shields, dedicated to the reduction of the {gamma}-ray and neutron fluxes. In the first part, I describe the implications of several mechanisms, related to trilinear R-parity violation, on double beta decay. The second part is dedicated to a detailed study of the tracking detector of the experiment: after a description of the different working tests, I present the determination of the characteristics of the tracking reconstruction (transverse and longitudinal resolution, by Geiger cell and precision on vertex determination, charge recognition). The last part corresponds to the analysis of the data taken by the experiment. On the one hand, an upper limit on the Tl{sup 208} activity of the sources has been determined: it is lower than 68 mBq/kg, at 90% of confidence level. On the other hand, I have developed and tested on these data a method in order to analyse the neutrinoless double beta decay signal; this method is based on a maximum of likelihood using all the available information. Using this method, I could determine a first and very preliminary upper limit on the effective mass of the neutrino. (author)

Preliminary results from a study of the double beta decay of 150Nd

International Nuclear Information System (INIS)

Perillo, I.M.C.; Chan, Y.D.; Hurley, D.; Lesko, K.T.; McDonald, R.J.; Moorhead, M.E.; Norman, E.B.; Smith, A.R.; Stokstad, R.G.

1996-01-01

We report the preliminary results from a study of the double beta decay of 150 Nd to the first 0 + excited state of 150 Sm. Our data consists of 50 days of counting 5 kg of natural Nd 2 O 3 at the LBNL-Oroville low background facility. The deduced lower limit for the half life of this decay mode is 4.9.10 19 years. (orig.)

Demonstration of Single-Barium-Ion Sensitivity for Neutrinoless Double-Beta Decay Using Single-Molecule Fluorescence Imaging

Energy Technology Data Exchange (ETDEWEB)

McDonald, A. D.; Jones, B. J. P.; Nygren, D. R.; Adams, C.; Álvarez, V.; Azevedo, C. D. R.; Benlloch-Rodríguez, J. M.; Borges, F. I. G. M.; Botas, A.; Cárcel, S.; Carrión, J. V.; Cebrián, S.; Conde, C. A. N.; Díaz, J.; Diesburg, M.; Escada, J.; Esteve, R.; Felkai, R.; Fernandes, L. M. P.; Ferrario, P.; Ferreira, A. L.; Freitas, E. D. C.; Goldschmidt, A.; Gómez-Cadenas, J. J.; González-Díaz, D.; Gutiérrez, R. M.; Guenette, R.; Hafidi, K.; Hauptman, J.; Henriques, C. A. O.; Hernandez, A. I.; Hernando Morata, J. A.; Herrero, V.; Johnston, S.; Labarga, L.; Laing, A.; Lebrun, P.; Liubarsky, I.; López-March, N.; Losada, M.; Martín-Albo, J.; Martínez-Lema, G.; Martínez, A.; Monrabal, F.; Monteiro, C. M. B.; Mora, F. J.; Moutinho, L. M.; Muñoz Vidal, J.; Musti, M.; Nebot-Guinot, M.; Novella, P.; Palmeiro, B.; Para, A.; Pérez, J.; Querol, M.; Repond, J.; Renner, J.; Riordan, S.; Ripoll, L.; Rodríguez, J.; Rogers, L.; Santos, F. P.; dos Santos, J. M. F.; Simón, A.; Sofka, C.; Sorel, M.; Stiegler, T.; Toledo, J. F.; Torrent, J.; Tsamalaidze, Z.; Veloso, J. F. C. A.; Webb, R.; White, J. T.; Yahlali, N.

2018-03-01

A new method to tag the barium daughter in the double beta decay of $^{136}$Xe is reported. Using the technique of single molecule fluorescent imaging (SMFI), individual barium dication (Ba$^{++}$) resolution at a transparent scanning surface has been demonstrated. A single-step photo-bleach confirms the single ion interpretation. Individual ions are localized with super-resolution ($\\sim$2~nm), and detected with a statistical significance of 12.9~$\\sigma$ over backgrounds. This lays the foundation for a new and potentially background-free neutrinoless double beta decay technology, based on SMFI coupled to high pressure xenon gas time projection chambers.

Demonstration of Single-Barium-Ion Sensitivity for Neutrinoless Double-Beta Decay Using Single-Molecule Fluorescence Imaging

Science.gov (United States)

McDonald, A. D.; Jones, B. J. P.; Nygren, D. R.; Adams, C.; Álvarez, V.; Azevedo, C. D. R.; Benlloch-Rodríguez, J. M.; Borges, F. I. G. M.; Botas, A.; Cárcel, S.; Carrión, J. V.; Cebrián, S.; Conde, C. A. N.; Díaz, J.; Diesburg, M.; Escada, J.; Esteve, R.; Felkai, R.; Fernandes, L. M. P.; Ferrario, P.; Ferreira, A. L.; Freitas, E. D. C.; Goldschmidt, A.; Gómez-Cadenas, J. J.; González-Díaz, D.; Gutiérrez, R. M.; Guenette, R.; Hafidi, K.; Hauptman, J.; Henriques, C. A. O.; Hernandez, A. I.; Hernando Morata, J. A.; Herrero, V.; Johnston, S.; Labarga, L.; Laing, A.; Lebrun, P.; Liubarsky, I.; López-March, N.; Losada, M.; Martín-Albo, J.; Martínez-Lema, G.; Martínez, A.; Monrabal, F.; Monteiro, C. M. B.; Mora, F. J.; Moutinho, L. M.; Muñoz Vidal, J.; Musti, M.; Nebot-Guinot, M.; Novella, P.; Palmeiro, B.; Para, A.; Pérez, J.; Querol, M.; Repond, J.; Renner, J.; Riordan, S.; Ripoll, L.; Rodríguez, J.; Rogers, L.; Santos, F. P.; dos Santos, J. M. F.; Simón, A.; Sofka, C.; Sorel, M.; Stiegler, T.; Toledo, J. F.; Torrent, J.; Tsamalaidze, Z.; Veloso, J. F. C. A.; Webb, R.; White, J. T.; Yahlali, N.; NEXT Collaboration

2018-03-01

A new method to tag the barium daughter in the double-beta decay of Xe 136 is reported. Using the technique of single molecule fluorescent imaging (SMFI), individual barium dication (Ba++ ) resolution at a transparent scanning surface is demonstrated. A single-step photobleach confirms the single ion interpretation. Individual ions are localized with superresolution (˜2 nm ), and detected with a statistical significance of 12.9 σ over backgrounds. This lays the foundation for a new and potentially background-free neutrinoless double-beta decay technology, based on SMFI coupled to high pressure xenon gas time projection chambers.

Nuclear transparency, B physics, and double beta decay. Annual report, February 1, 1996 - January 31, 1997

International Nuclear Information System (INIS)

Nicholson, H.W.

1996-07-01

This report describes the publication of results of a search for neutrinoless double-beta decay of molybdenum 100 and preparation of a paper on statistical analysis techniques used, developments related to purification techniques for the molybdenum, and other related work; progress in redesign, rebuilding, and installation of the Brookhaven EVA detector's superconducting magnet and cryogenic system; and the testing of detector components for SLAC's BaBar experiment. 3 refs

A segmented, enriched N-type germanium detector for neutrinoless double beta-decay experiments

Science.gov (United States)

Leviner, L. E.; Aalseth, C. E.; Ahmed, M. W.; Avignone, F. T.; Back, H. O.; Barabash, A. S.; Boswell, M.; De Braeckeleer, L.; Brudanin, V. B.; Chan, Y.-D.; Egorov, V. G.; Elliott, S. R.; Gehman, V. M.; Hossbach, T. W.; Kephart, J. D.; Kidd, M. F.; Konovalov, S. I.; Lesko, K. T.; Li, Jingyi; Mei, D.-M.; Mikhailov, S.; Miley, H.; Radford, D. C.; Reeves, J.; Sandukovsky, V. G.; Umatov, V. I.; Underwood, T. A.; Tornow, W.; Wu, Y. K.; Young, A. R.

2014-01-01

We present data characterizing the performance of the first segmented, N-type Ge detector, isotopically enriched to 85% 76Ge. This detector, based on the Ortec PT6×2 design and referred to as SEGA (Segmented, Enriched Germanium Assembly), was developed as a possible prototype for neutrinoless double beta-decay measurements by the MAJORANA collaboration. We present some of the general characteristics (including bias potential, efficiency, leakage current, and integral cross-talk) for this detector in its temporary cryostat. We also present an analysis of the resolution of the detector, and demonstrate that for all but two segments there is at least one channel that reaches the MAJORANA resolution goal below 4 keV FWHM at 2039 keV, and all channels are below 4.5 keV FWHM.

Measurement of the 2{nu}{beta}{beta} decay of {sup 100}Mo to the excited 0{sub 1}{sup +} state in the NEMO3 experiment

Energy Technology Data Exchange (ETDEWEB)

Vala, L

2003-09-01

The NEMO3 detector was designed for the study of double beta decay and in particular to search for the neutrinoless double beta decay process (0{nu}{beta}{beta}). The intended sensitivity in terms of a half-life limit for the 0{nu}{beta}{beta} decay is of the order of 10{sup 25} y which corresponds to an effective neutrino mass m{sub {nu}} on the level of (0.3 - 0.1) eV. The 0{nu}{beta}{beta} process is today the most promising test of the Majorana nature of the neutrino. The detector was constructed in the Modane Underground Laboratory (LSM) in France by an international collaboration including France, Russia, the Czech Republic, the USA, the UK, Finland, and Japan. The experiment has been taking data since May 2002. The quantity of {sup 100}Mo in the detector (7 kg) allows an efficient measurement of the two-neutrino double beta decay (2{nu}{beta}{beta}) of {sup 100}Mo to the excited 0{sub 1}{sup +} state (eeN{gamma} channel). Monte-Carlo simulations of the effect and of all the relative sources of background have been produced in order to define a set of appropriate selection criteria. Both Monte-Carlo simulations and special runs with sources of {sup 208}Tl and {sup 214}Bi showed that the only significant background in the eeN{gamma} channel comes from radon that penetrated inside the wire chamber of NEMO3. The experimental data acquired from May 2002 to May 2003 have been analysed in order to determine the signal from the 2{nu}{beta}{beta} decay of {sup 100}Mo to the excited 0{sub 1}{sup +} state and the corresponding background level. The physical result, which was obtained at the level of four standard deviations, is given in the form of an interval of half-life values at 95% confidence level: [5.84*10{sup 20}, 2.26*10{sup 21}] y for method A and [5.83*10{sup 20}, 1.71*10{sup 21}] y for method B. (author)

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

International Nuclear Information System (INIS)

Brugnera, R.

2009-01-01

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)

A large scale double beta and dark matter experiment: GENIUS

International Nuclear Information System (INIS)

Hellmig, J.; Klapdor-Kleingrothaus, H.V.

1997-01-01

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 present here a study of a project proposed recently, which would operate one ton of 'naked' enriched germanium-detectors in liquid nitrogen as shielding in an underground setup (GENIUS). It improves the sensitivity to neutrino masses to 0.01 eV. A ten ton version would probe neutrino masses even down to 10 -3 eV. The first version would allow 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 supersymmetry models, leptoquark masses and mechanism and right-handed W-boson masses comparable to LHC. The second issue of the experiment is the search for dark matter in the universe. The entire MSSM parameter space for prediction of neutralinos as dark matter particles could be covered already in a first step of the full experiment with the same purity requirements, but using only 100 kg of 76 Ge or even of natural Ge making the experiment competitive to LHC in the search for supersymmetry.The layout of the proposed experiment is discussed and the shielding and purity requirements are studied using GEANT Monte Carlo simulations. As a demonstration of the feasibility of theexperiment first results of operating a 'naked' Ge detector in liquid nitrogen are presented. (orig.)

Analysis method for the search for neutrinoless double beta decay in the NEMO3 experiment: study of the background and first results; Methode d'analyse pour la recherche de la double desintegration {beta} sans emission de neutrinos dans l'experience NEMO3. Etude du bruit de fond et premiers resultats

Energy Technology Data Exchange (ETDEWEB)

Etienvre, A.I

2003-04-15

The NEMO3 detector, installed in the Frejus Underground Laboratory, is dedicated to the study of neutrinoless double beta decay: the observation of this process would sign the massive and Majorana nature of neutrino. The experiment consists in very thin central source foils (the total mass is equal to 10 kg), a tracking detector made of drift cells operating in Geiger mode, a calorimeter made of plastic scintillators associated to photomultipliers, a coil producing a 30 gauss magnetic field and two shields, dedicated to the reduction of the {gamma}-ray and neutron fluxes. In the first part, I describe the implications of several mechanisms, related to trilinear R-parity violation, on double beta decay. The second part is dedicated to a detailed study of the tracking detector of the experiment: after a description of the different working tests, I present the determination of the characteristics of the tracking reconstruction (transverse and longitudinal resolution, by Geiger cell and precision on vertex determination, charge recognition). The last part corresponds to the analysis of the data taken by the experiment. On the one hand, an upper limit on the Tl{sup 208} activity of the sources has been determined: it is lower than 68 mBq/kg, at 90% of confidence level. On the other hand, I have developed and tested on these data a method in order to analyse the neutrinoless double beta decay signal; this method is based on a maximum of likelihood using all the available information. Using this method, I could determine a first and very preliminary upper limit on the effective mass of the neutrino. (author)

Searching Neutrinoless Double Beta Decay with GERDA Phase II

Science.gov (United States)

Agostini, M.; Bakalyarov, A. M.; Balata, M.; Barabanov, I.; Baudis, L.; Bauer, C.; Bellotti, E.; Belogurov, S.; Bettini, A.; Bezrukov, L.; Bode, T.; Brudanin, V.; Brugnera, R.; Caldwell, A.; Cattadori, C.; Chernogorov, A.; Comellato, T.; D’Andrea, V.; Demidova, E. V.; di Marco, N.; Domula, A.; Doroshkevich, E.; Egorov, V.; Falkenstein, R.; Gangapshev, A.; Garfagnini, A.; Giordano, M.; Gooch, C.; Grabmayr, P.; Gurentsov, V.; Gusev, K.; Hahne, C.; Hakenmüller, J.; Hegai, A.; Heisel, M.; Hemmer, S.; Hiller, R.; Hofmann, W.; Holl, P.; Hult, M.; Inzhechik, L. V.; Ioannucci, L.; Csáthy, J. Janicskó; Jochum, J.; Junker, M.; Kazalov, V.; Kermaidic, Y.; Kihm, T.; Kirpichnikov, I. V.; Kirsch, A.; Kish, A.; Klimenko, A.; Kneißl, R.; Knöpfle, K. T.; Kochetov, O.; Kornoukhov, V. N.; Kuzminov, V. V.; Laubenstein, M.; Lazzaro, A.; Lindner, M.; Lippi, I.; Lubashevskiy, A.; Lubsandorzhiev, B.; Lutter, G.; Macolino, C.; Majorovits, B.; Maneschg, W.; Marissens, G.; Miloradovic, M.; Mingazheva, R.; Misiaszek, M.; Moseev, P.; Nemchenok, I.; Nisi, S.; Panas, K.; Pandola, L.; Pelczar, K.; Pullia, A.; Ransom, C.; Reissfelder, M.; Riboldi, S.; Rumyantseva, N.; Sada, C.; Sala, E.; Salamida, F.; Schmitt, C.; Schneider, B.; Schreiner, J.; Schulz, O.; Schweisshelm, B.; Schwingenheuer, B.; Schönert, S.; Schütz, A.-K.; Seitz, H.; Selivanenko, O.; Shevchik, E.; Shirchenko, M.; Simgen, H.; Smolnikov, A.; Stanco, L.; Vanhoefer, L.; Vasenko, A. A.; Veresnikova, A.; von Sturm, K.; Wagner, V.; Wegmann, A.; Wester, T.; Wiesinger, C.; Wojcik, M.; Yanovich, E.; Zhitnikov, I.; Zhukov, S. V.; Zinatulina, D.; Zschocke, A.; Zsigmond, A. J.; Zuber, K.; Zuzel, G.

An observation of neutrinoless double beta (0νββ) decay would allow to shed light onto the nature of neutrinos. GERDA (GERmanium Detector Array) aims to discover this process in a background-free search using 76Ge. The experiment is located at the Laboratori Nazionali del Gran Sasso (LNGS) of the Istituto Nazionale di Fisica Nucleare (INFN) in Italy. Bare, isotopically enriched, high purity germanium detectors are operated in liquid argon. GERDA follows a staged approach. In Phase II 35.6 kg of enriched germanium detectors are operated since December 2015. The application of active background rejection methods, such as a liquid argon scintillation light read-out and pulse shape discrimination of germanium detector signals, allows to reduce the background index to the intended level of 10‑3 cts/(keVṡkgṡyr). No evidence for the 0νββ decay has been found in 23.2 kgṡyr of Phase II data, and together with data from Phase I the up-to-date most stringent half-life limit for this process in 76Ge has been established, at a median sensitivity of 5.8ṡ1025yr the 90% C.L. lower limit is 8.0ṡ1025yr.

Observed double beta decay spectra from 82Se, 100Mo, and 150Nd

International Nuclear Information System (INIS)

Elliott, S.R.; Moe, M.K.; Nelson, M.A.; Vient, M.A.

1993-01-01

Two-electron events resembling double beta decay are being observed at energies beyond the die-off of the spectrum predicted for the two-neutrino mode. The anomaly appears in three isotopes having different half lives and Q-values. Tests are now underway to determine its origin. (orig.)

An experimental investigation of double beta decay of 100Mo

International Nuclear Information System (INIS)

Dougherty, B.L.

1988-01-01

New limits on half-lives for several double beta decay modes of 100 Mo 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 96 Mo were used to assess remaining backgrounds. With 0.1 mole years of 100 Mo data collected, the lower half-life limits at 90% confidence were 2.7 /times/ 10 18 years for decay via the two-neutrino mode, 5.2 /times/10 19 years for decay with the emission of a Majoron, and 1.6 /times/ 10 20 years and 2.2 /times/ 10 21 years for neutrinoless 0 + → 2 + and 0 + → 0 + transitions, respectively. 50 refs., 38 figs., 11 tabs

Theory of neutrinoless double beta decay

CERN Document Server

Vergados, J.D.; Simkovic, F.

2012-01-01

Neutrinoless double beta decay, which is a very old and yet elusive process, is reviewed. Its observation will signal that lepton number is not conserved and the neutrinos are Majorana particles. More importantly it is our best hope for determining the absolute neutrino mass scale at the level of a few tens of meV. To achieve the last goal certain hurdles have to be overcome involving particle, nuclear and experimental physics. Nuclear physics is important for extracting the useful information from the data. One must accurately evaluate the relevant nuclear matrix elements, a formidable task. To this end, we review the sophisticated nuclear structure approaches recently been developed, which give confidence that the needed nuclear matrix elements can be reliably calculated. From an experimental point of view it is challenging, since the life times are long and one has to fight against formidable backgrounds. If a signal is found, it will be a tremendous accomplishment. Then, of course, the real task is going ...

First test of an enriched {sup 116}CdWO{sub 4} scintillating bolometer for neutrinoless double-beta-decay searches

Energy Technology Data Exchange (ETDEWEB)

Barabash, A.S.; Konovalov, S.I.; Umatov, V.I. [ITEP, National Research Centre ' ' Kurchatov Institute' ' , Moscow (Russian Federation); Danevich, F.A. [MSP, Institute for Nuclear Research, Kyiv (Ukraine); Gimbal-Zofka, Y. [Univ. Paris-Sud, CNRS/IN2P3, Universite Paris-Saclay, CSNSM, Orsay (France); Linnaeus University, Department of Physics and Electrical Engineering, Kalmar (Sweden); Giuliani, A.; Mancuso, M. [Univ. Paris-Sud, CNRS/IN2P3, Universite Paris-Saclay, CSNSM, Orsay (France); DISAT, Universita dell' Insubria, Como (Italy); Marcillac, P. de; Marnieros, S.; Novati, V.; Olivieri, E. [Univ. Paris-Sud, CNRS/IN2P3, Universite Paris-Saclay, CSNSM, Orsay (France); Nones, C.; Zolotarova, A.S. [DSM/IRFU, CEA Saclay, Gif-sur-Yvette Cedex (France); Poda, D.V. [MSP, Institute for Nuclear Research, Kyiv (Ukraine); Univ. Paris-Sud, CNRS/IN2P3, Universite Paris-Saclay, CSNSM, Orsay (France); Shlegel, V.N. [Nikolaev Institute of Inorganic Chemistry, Novosibirsk (Russian Federation); Tretyak, V.I. [MSP, Institute for Nuclear Research, Kyiv (Ukraine); INFN, Sezione di Roma, Rome (Italy)

2016-09-15

For the first time, a cadmium tungstate crystal scintillator enriched in {sup 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 high energy resolution (2-7 keV FWHM in 0.2-2.6 MeV γ energy range and 7.5 keV FWHM at the {sup 116}Cd double-beta decay transition energy of 2813 keV), a powerful particle identification capability and a high level of internal radio-purity. These results prove that cadmium tungstate is a 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). (orig.)

The processing of enriched germanium for the MAJORANA DEMONSTRATOR and R&D for a next generation double-beta decay experiment

Science.gov (United States)

Abgrall, N.; Arnquist, I. J.; Avignone, F. T., III; Barabash, A. S.; Bertrand, F. E.; Bradley, A. W.; Brudanin, V.; Busch, M.; Buuck, M.; Caja, J.; Caja, M.; Caldwell, T. S.; Christofferson, C. D.; Chu, P.-H.; Cuesta, C.; Detwiler, J. A.; Dunagan, C.; Dunstan, D. T.; Efremenko, Yu.; Ejiri, H.; Elliott, S. R.; Gilliss, T.; Giovanetti, G. K.; Goett, J.; Green, M. P.; Gruszko, J.; Guinn, I. S.; Guiseppe, V. E.; Haufe, C. R. S.; Henning, R.; Hoppe, E. W.; Jasinski, B. R.; Kidd, M. F.; Konovalov, S. I.; Kouzes, R. T.; Lopez, A. M.; MacMullin, J.; Martin, R. D.; Massarczyk, R.; Meijer, S. J.; Mertens, S.; Meyer, J. H.; Myslik, J.; O'Shaughnessy, C.; Poon, A. W. P.; Radford, D. C.; Rager, J.; Reine, A. L.; Reising, J. A.; Rielage, K.; Robertson, R. G. H.; Shanks, B.; Shirchenko, M.; Suriano, A. M.; Tedeschi, D.; Toth, L. M.; Trimble, J. E.; Varner, R. L.; Vasilyev, S.; Vetter, K.; Vorren, K.; White, B. R.; Wilkerson, J. F.; Wiseman, C.; Xu, W.; Yakushev, E.; Yu, C.-H.; Yumatov, V.; Zhitnikov, I.; Zhu, B. X.

2018-01-01

The MAJORANA DEMONSTRATOR is an array of point-contact Ge detectors fabricated from Ge isotopically enriched to 88% in 76 Ge to search for neutrinoless double beta decay. The processing of Ge for germanium detectors is a well-known technology. However, because of the high cost of Ge enriched in 76 Ge special procedures were required to maximize the yield of detector mass and to minimize exposure to cosmic rays. These procedures include careful accounting for the material; shielding it to reduce cosmogenic generation of radioactive isotopes; and development of special reprocessing techniques for contaminated solid germanium, shavings, grindings, acid etchant and cutting fluids from detector fabrication. Processing procedures were developed that resulted in a total yield in detector mass of 70%. However, none of the acid-etch solution and only 50% of the cutting fluids from detector fabrication were reprocessed. Had they been processed, the projections for the recovery yield would be between 80% and 85%. Maximizing yield is critical to justify a possible future ton-scale experiment. A process for recovery of germanium from the acid-etch solution was developed with yield of about 90%. All material was shielded or stored underground whenever possible to minimize the formation of 68Ge by cosmic rays, which contributes background in the double-beta decay region of interest and cannot be removed by zone refinement and crystal growth. Formation of 68Ge was reduced by a significant factor over that in natural abundance detectors not protected from cosmic rays.

The Gerda search for neutrinoless double beta decay

Science.gov (United States)

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.

Neutron Interactions in the CUORE Neutrinoless Double Beta Decay Experiment

Energy Technology Data Exchange (ETDEWEB)

Dolinski, Michelle Jean [Univ. of California, Berkeley, CA (United States)

2008-10-01

Neutrinoless double beta decay (0vDBD) is a lepton-number violating process that can occur only for a massive Majorana neutrino. The search for 0vDBD 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 0vDBD can provide information about the absolute mass scale of the neutrino. The Cuoricino experiment was a sensitive search for 0vDBD, as well as a proof of principle for the next generation experiment, CUORE. CUORE will search for 0vDBD of ¹³⁰Te with a ton-scale array of unenriched TeO₂ bolometers. By increasing mass and decreasing the background for 0vDBD, 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^-6. Because of the extreme low background requirements for CUORE, it is important that all potential sources of background in the 0vDBD 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 (α,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 the GEANIE

Exploring the neutrinoless double beta decay in the inverted neutrino hierarchy with bolometric detectors

Energy Technology Data Exchange (ETDEWEB)

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.)

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

International Nuclear Information System (INIS)

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 ∝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.)

Neutrinoless double-beta decay in left-right symmetric models

International Nuclear Information System (INIS)

Picciotto, C.E.; Zahir, M.S.

1982-06-01

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

Few active mechanisms of the neutrinoless double beta-decay and effective mass of Majorana neutrinos

CERN Document Server

Simkovic, Fedor; Faessler, Amand

2010-01-01

It is well known that there exist many mechanisms that may contribute to neutrinoless double beta decay (0nbb-decay). By exploiting the fact that the associated nuclear matrix elements are target dependent we show that, given definite experimental results on a sufficient number of targets, one can determine or sufficiently constrain all lepton violating parameters including the mass term. As a specific example we show that, assuming the observation of the 0nbb-decay in three different nuclei, e.g., 76Ge, 100Mo and 130Te, and just three lepton number violating mechanisms (light and heavy neutrino mass mechanisms as well as R-parity breaking SUSY mechanism) being active, there are only four different solutions for the lepton violating parameters, provided that they are relatively real. In particular, assuming evidence of the 0nbb-decay of 76Ge, the effective neutrino Majorana mass |m_bb| can be almost uniquely extracted by utilizing other existing constraints (cosmological observations and tritium beta-decay ex...

Simulation studies of muon-produced background events deep underground and consequences for double beta decay experiments

Science.gov (United States)

Massarczyk, Ralph; Majorana Collaboration

2015-10-01

Cosmic radiation creates a significant background for low count rate experiments. The Majorana demonstrator experiment is located at the Sanford Underground Research Facility at a depth of 4850ft below the surface but it can still be penetrated by cosmic muons with initial energies above the TeV range. The interaction of muons with the rock, the shielding material in the lab and the detector itself can produce showers of secondary particles, like fast neutrons, which are able to travel through shielding material and can produce high-energy γ-rays via capture or inelastic scattering. The energy deposition of these γ rays in the detector can overlap with energy region of interest for the neutrino-less double beta decay. Recent studies for cosmic muons penetrating the Majorana demonstrator are made with the Geant4 code. The results of these simulations will be presented in this talk and an overview of the interaction of the shower particles with the detector, shielding and veto system will be given. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, the Particle Astrophysics Program of the National Science Foundation, and the Sanford Underground Research Facility. Supported by U.S. Department of Energy through the LANL/LDRD Program.

Nuclear Matrix Elements for the $\\beta\\beta$ Decay of the $^{76}$Ge

CERN Document Server

Brown, B A; Horoi, M

2015-01-01

The nuclear matrix elements for two-neutrino double-beta (2 n$\\beta\\beta$ ) and zero-neutrino double-beta (0 n$\\beta\\beta$) decay of 76 Ge are evaluated in terms of the configuration interaction (CI), quasiparticle random phase approximation (QRPA) and interacting boson model (IBM) methods. We show that the decomposition of the matrix elements in terms of interemediate states in 74 Ge is dominated by ground state of this nucleus. We consider corrections to the CI results that arise from configurations admixtures involving orbitals out-side of the CI configuration space by using results from QRPA, many-body-perturbation theory, and the connections to related observables. The CI two-neutrino matrix element is reduced due to the inclusion of spin-orbit partners, and to many-body correlations connected with Gamow-Teller beta decay. The CI zero-neutrino matrix element for the heavy neutrino is enhanced due to particle-particle correlations that are connected with the odd-even oscillations in the nuclear masse...

Beta-gamma spectroscopy for double beta decays and Lepton number conservation

International Nuclear Information System (INIS)

Ejiri, H.; Takahashi, N.; Shibata, T.; Nagai, Y.; Okada, K.; Kamikubota, N.; Watanabe, T.

1984-01-01

In this paper neutrino-less double β decays (Oν ββ) of /sup 76/Ge were studied by means of the newly developed ELEGANTS (Electron gamma-ray neutrino spectrometer). It consists of a 171 cc pure Ge detector surrounded bu a big 4π-NaI detector, and active and inactive filters. Measurement of both the electron signal from the Ge detector and γ-ray signals from the 4π-NaI detector made it possible to select the true double decay events from background events due to the other radio-active isotopes and cosmic rays. The ELEGANTS showed the highest sensitivity for detecting the neutrino-less double β decay. The preliminary data obtained so far give a lower limit of the half life T/sub 1/2/≥2.2 10/sup 22/y for the O/sup +/→O/sup +/ Oν ββ decay and T/sub 1/2/ ≥1.5.10/sup 22/y for the O/sup +/→2/sup +/ Oν ββ decay of /sup 76/Ge

The double beta decay spectra of 82Se, 100Mo, and 150Nd

International Nuclear Information System (INIS)

Nelson, M.A.; Moe, M.K.; Vient, M.A.; Elliott, S.R.

1992-01-01

The double beta decay electron energy spectra of 82 Se, 100 Mo, and 150 Nd have been measured with a time projection chamber, and departures from the expected two-neutrino spectral shapes have been observed. Efforts to reduce possible background contamination have been made, and tests are now being done in an effort to determine whether the anomalous signals are real effects, or simply experimental artifacts

Double Beta Decay - Physics Beyond the Standard Model Now, and in Future (GENIUS)

Science.gov (United States)

Klapdor-Kleingrothaus, H. V.

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), com-positeness, right-handed W boson mass and others. These results are comfortably competitive to corresponding results from high-energy accelerators like TEVA-TRON, HERA, etc. Second, future perspectives of ʲʲ 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.

Neutrino mass from laboratory: contribution of double beta decay to the neutrino mass matrix

International Nuclear Information System (INIS)

Klapdor-Kleingrothaus, H.V.

2001-01-01

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 > < 0.26 eV practically excludes degenerate ν mass scenarios allowing neutrinos as hot dark matter in the universe for the smallangle MSW solution of the solar neutrino problem. It probes cosmological models including hot dark matter already now on the level of future satellite experiments MAP and PLANCK. It further probes many topics of beyond SM physics at the TeV scale. Future experiments should give access to the multi-TeV range and complement on many ways the search for new physics at future colliders like LHC and NLC. For neutrino physics some of them (GENIUS) will allow to test almost all neutrino mass scenarios allowed by the present neutrino oscillation experiments

Study of the background of the neutrinoless double {beta} decay with the detector NEMO 2: contribution arising from the radon diffusion and internal pollution of the source {sup 214}Bi have been estimated; Etude du bruit de fond de la double-desintegration {beta} sans emission de neutrino dans le detecteur NEMO 2: contribution du radon ambiant et mesure de la pollution interne de la source en {sup 214}Bi

Energy Technology Data Exchange (ETDEWEB)

Mauger, F.

1995-02-01

The NEMO experiment is designed to understand the nature of the neutrino by studying the double beta decay of Mo-100 which is related to the Majorana neutrino effective mass. In this kind of experiment a good understanding of the different sources of background is crucial as only few events are expected per year at the required level of sensitivity. In this thesis we present the main theoretical and experimental aspects of the measurement of the neutrinoless double beta decay of Mo-100 with the prototype detector NEMO2. The goal of this study is to obtain a realistic interpretation of the few events detected at high energy in the two-electron channel as a background to neutrinoless double beta decay. In particular, the contribution arising from Bi-214 has been investigated. These events have been selected and analysed by means of the beta-alpha decays of Bi-214 into Pb-210. The events are characterized by a delayed track in the wire chamber and the corresponding signal is rather clean. The study has demonstrated the diffusion of Rn-222 into the detector and its contribution to Bi-214 pollution has been estimated. A measurement of the Bi-214 internal contamination of the source has been made as well as an estimation of the Bi-214 deposit due to Rn-222. As a result of this study it appears that, under the conditions of the NEMO2 experiment, the Bi and Rn contributions are of the same order of magnitude as the background induced at high energy by two-neutrino double beta decay. In conclusion, the backgrounds of the neutrinoless double beta decay of Mo-100 are well understood in the NEMO2 experiment leading to an extrapolation for the NEMO3 experiment. (authors).

The contribution of light Majorana neutrinos to neutrinoless double beta decay and cosmology

Energy Technology Data Exchange (ETDEWEB)

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.

Search for double-beta decay of 136Xe to excited states of 136Ba with the KamLAND-Zen experiment

Science.gov (United States)

Asakura, K.; Gando, A.; Gando, Y.; Hachiya, T.; Hayashida, S.; Ikeda, H.; Inoue, K.; Ishidoshiro, K.; Ishikawa, T.; Ishio, S.; Koga, M.; Matsuda, S.; Mitsui, T.; Motoki, D.; Nakamura, K.; Obara, S.; Otani, M.; Oura, T.; Shimizu, I.; Shirahata, Y.; Shirai, J.; Suzuki, A.; Tachibana, H.; Tamae, K.; Ueshima, K.; Watanabe, H.; Xu, B. D.; Yoshida, H.; Kozlov, A.; Takemoto, Y.; Yoshida, S.; Fushimi, K.; Banks, T. I.; Berger, B. E.; Fujikawa, B. K.; O'Donnell, T.; Winslow, L. A.; Efremenko, Y.; Karwowski, H. J.; Markoff, D. M.; Tornow, W.; Detwiler, J. A.; Enomoto, S.; Decowski, M. P.

2016-02-01

A search for double-beta decays of 136Xe to excited states of 136Ba has been performed with the first phase data set of the KamLAND-Zen experiment. The 01+, 21+ and 22+ transitions of 0 νββ decay were evaluated in an exposure of 89.5 kg ṡyr of 136Xe, while the same transitions of 2 νββ decay were evaluated in an exposure of 61.8 kg ṡyr. No excess over background was found for all decay modes. The lower half-life limits of the 21+ state transitions of 0 νββ and 2 νββ decay were improved to T1/20ν (0+ →21+) > 2.6 ×1025 yr and T1/22ν (0+ →21+) > 4.6 ×1023 yr (90% C.L.), respectively. We report on the first experimental lower half-life limits for the transitions to the 01+ state of 136Xe for 0 νββ and 2 νββ decay. They are T1/20ν (0+ →01+) > 2.4 ×1025 yr and T1/22ν (0+ → 01+) > 8.3 ×1023 yr (90% C.L.). The transitions to the 22+ states are also evaluated for the first time to be T1/20ν (0+ →22+) > 2.6 ×1025 yr and T1/22ν (0+ →22+) > 9.0 ×1023 yr (90% C.L.). These results are compared to recent theoretical predictions.

LUCIFER, a potentially background-free approach to the search for neutrinoless double beta decay

Energy Technology Data Exchange (ETDEWEB)

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.

New results for double-beta decay of {sup 100}Mo to excited final states of {sup 100}Ru using the TUNL-ITEP apparatus

Energy Technology Data Exchange (ETDEWEB)

Kidd, M.F.; Esterline, J.H. [Department of Physics, Duke University and Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States); Tornow, W. [Department of Physics, Duke University and Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States)], E-mail: tornow@tunl.duke.edu; Barabash, A.S.; Umatov, V.I. [Institute for Theoretical and Experimental Physics, 117259 Moscow (Russian Federation)

2009-04-15

The coincidence detection efficiency of the TUNL-ITEP apparatus designed for measuring half-life times of two-neutrino double-beta (2{nu}{beta}{beta}) decay transitions to excited final states in daughter nuclei has been measured with a factor of 2.4 improved accuracy. In addition, the previous measuring time of 455 days for the study of the {sup 100}Mo 2{nu}{beta}{beta} decay to the first excited 0{sub 1}{sup +} state in {sup 100}Ru has been increased by 450 days, and a new result (combined with the previous measurement obtained with the same apparatus) for this transition is presented: T{sub 1/2}=[5.5{sub -0.8}{sup +1.2}(stat){+-}0.3(syst)]x10{sup 20} yr. Measured 2{nu}{beta}{beta} decay half-life times to excited states can be used to test the reliability of nuclear matrix element calculations needed for determining the effective neutrino mass from zero-neutrino double-beta decay data. We also present new limits for transitions to higher excited states in {sup 100}Ru which, if improved, may be of interest for more exotic conjectures, like a bosonic component to neutrino statistics.

The NUMEN project: NUclear Matrix Elements for Neutrinoless double beta decay

Science.gov (United States)

Cappuzzello, F.; Agodi, C.; Cavallaro, M.; Carbone, D.; Tudisco, S.; Lo Presti, D.; Oliveira, J. R. B.; Finocchiaro, P.; Colonna, M.; Rifuggiato, D.; Calabretta, L.; Calvo, D.; Pandola, L.; Acosta, L.; Auerbach, N.; Bellone, J.; Bijker, R.; Bonanno, D.; Bongiovanni, D.; Borello-Lewin, T.; Boztosun, I.; Brunasso, O.; Burrello, S.; Calabrese, S.; Calanna, A.; Chávez Lomelí, E. R.; D'Agostino, G.; De Faria, P. N.; De Geronimo, G.; Delaunay, F.; Deshmukh, N.; Ferreira, J. L.; Fisichella, M.; Foti, A.; Gallo, G.; Garcia-Tecocoatzi, H.; Greco, V.; Hacisalihoglu, A.; Iazzi, F.; Introzzi, R.; Lanzalone, G.; Lay, J. A.; La Via, F.; Lenske, H.; Linares, R.; Litrico, G.; Longhitano, F.; Lubian, J.; Medina, N. H.; Mendes, D. R.; Moralles, M.; Muoio, A.; Pakou, A.; Petrascu, H.; Pinna, F.; Reito, S.; Russo, A. D.; Russo, G.; Santagati, G.; Santopinto, E.; Santos, R. B. B.; Sgouros, O.; da Silveira, M. A. G.; Solakci, S. O.; Souliotis, G.; Soukeras, V.; Spatafora, A.; Torresi, D.; Magana Vsevolodovna, R.; Yildirim, A.; Zagatto, V. A. B.

2018-05-01

The article describes the main achievements of the NUMEN project together with an updated and detailed overview of the related R&D activities and theoretical developments. NUMEN proposes an innovative technique to access the nuclear matrix elements entering the expression of the lifetime of the double beta decay by cross section measurements of heavy-ion induced Double Charge Exchange (DCE) reactions. Despite the fact that the two processes, namely neutrinoless double beta decay and DCE reactions, are triggered by the weak and strong interaction respectively, important analogies are suggested. The basic point is the coincidence of the initial and final state many-body wave functions in the two types of processes and the formal similarity of the transition operators. First experimental results obtained at the INFN-LNS laboratory for the 40Ca(18O,18Ne)40Ar reaction at 270MeV give an encouraging indication on the capability of the proposed technique to access relevant quantitative information. The main experimental tools for this project are the K800 Superconducting Cyclotron and MAGNEX spectrometer. The former is used for the acceleration of the required high resolution and low emittance heavy-ion beams and the latter is the large acceptance magnetic spectrometer for the detection of the ejectiles. The use of the high-order trajectory reconstruction technique, implemented in MAGNEX, allows to reach the experimental resolution and sensitivity required for the accurate measurement of the DCE cross sections at forward angles. However, the tiny values of such cross sections and the resolution requirements demand beam intensities much larger than those manageable with the present facility. The on-going upgrade of the INFN-LNS facilities in this perspective is part of the NUMEN project and will be discussed in the article.

LUCIFER: a scintillating bolometer array for the search of neutrinoless double beta decay

International Nuclear Information System (INIS)

Cardani, Laura

2011-01-01

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 82 Se 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.

Double-beta decay measurement of 100Mo to the excited 01+ state of 100Ru in the NEMO3 experiment - R/D program for SuperNEMO: development of a BiPo detector to measure ultra low contaminations in the source foils

International Nuclear Information System (INIS)

Chapon, A.

2011-10-01

The NEMO3 detector was designed for the study of double beta decay and in particular the search for neutrinoless double beta decay (ββ0ν). The quantity of 100 Mo in the detector (7 kg) allows also a competitive measurement of the two-neutrino double beta decay (ββ2ν) of 100 Mo to the excited 0 1 + state of 100 Ru (eeNγ channel). Monte-Carlo simulations of the effect and of all the possible sources of background have been studied in order to determine their contributions to the full NEMO3 experimental data (2003-2011). These one have then been analysed: the ββ2ν decay half-life has been measured, and a limit on the ββ0ν decay has been obtained. Moreover, the SuperNEMO experiment aims to reach a sensitivity up to 10 26 years on the half-life of neutrinoless double beta decay. The SuperNEMO detector radioactivity has to be as low as possible. Especially radio-purity levels of 2 μBq*kg -1 in 208 Tl and 10 μBq*kg -1 in 214 Bi are required for the source foils. The gamma-spectrometry can not measure such low contamination levels. Hence, a BiPo dedicated detector has been developed to measure 208 Tl and 214 Bi contaminations, identifying the Bi→Po→Pb β-α chains. A proof of principle has been performed and the detector background has been measured. Assuming these values, a full BiPo detector of 3.6 m 2 can achieve the required sensitivities for the SuperNEMO source foils within six months of measurement. (author)

Investigation of double beta decay of {sup 100}Mo to excited states of {sup 100}Ru

Energy Technology Data Exchange (ETDEWEB)

Arnold, R. [IPHC, UPL, CNRS/IN2P3, F-67037 Strasbourg (France); Augier, C. [LAL, Univ Paris-Sud, CNRS/IN2P3, F-91405 Orsay (France); Barabash, A.S. [ITEP, Institute of Theoretical and Experimental Physics, 117218 Moscow (Russian Federation); Basharina-Freshville, A. [University College London, London WC1E 6BT (United Kingdom); Blondel, S. [LAL, Univ Paris-Sud, CNRS/IN2P3, F-91405 Orsay (France); Blot, S. [University of Manchester, Manchester M13 9PL (United Kingdom); Bongrand, M. [LAL, Univ Paris-Sud, CNRS/IN2P3, F-91405 Orsay (France); Brudanin, V. [JINR, Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Busto, J. [CPPM, Université de Marseille, CNRS/IN2P3, F-13288 Marseille (France); Caffrey, A.J. [Idaho National Laboratory, Idaho Falls, ID 83415 (United States); Čermák, P. [IEAP, Czech Technical University in Prague, CZ-12800 Prague (Czech Republic); Cerna, C. [CENBG, Université Bordeaux, CNRS/IN2P3, F-33175 Gradignan (France); Chapon, A. [LPC Caen, ENSICAEN, Université de Caen, CNRS/IN2P3, F-14050 Caen (France); Chauveau, E. [University of Manchester, Manchester M13 9PL (United Kingdom); Dragounová, L. [National Radiation Protection Institute, CZ-14000 Prague (Czech Republic); Duchesneau, D. [LAPP, Université de Savoie, CNRS/IN2P3, F-74941 Annecy-le-Vieux (France); Durand, D. [LPC Caen, ENSICAEN, Université de Caen, CNRS/IN2P3, F-14050 Caen (France); Egorov, V. [JINR, Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Eurin, G. [LAL, Univ Paris-Sud, CNRS/IN2P3, F-91405 Orsay (France); University College London, London WC1E 6BT (United Kingdom); Evans, J.J. [University of Manchester, Manchester M13 9PL (United Kingdom); and others

2014-05-15

Double beta decay of {sup 100}Mo to the excited states of daughter nuclei has been studied using a 600 cm{sup 3} low-background HPGe detector and an external source consisting of 2588 g of 97.5% enriched metallic {sup 100}Mo, which was formerly inside the NEMO-3 detector and used for the NEMO-3 measurements of {sup 100}Mo. The half-life for the two-neutrino double beta decay of {sup 100}Mo to the excited 0{sub 1}{sup +} state in {sup 100}Ru is measured to be T{sub 1/2}=[7.5±0.6(stat)±0.6(syst)]⋅10{sup 20} yr. For other (0ν+2ν) transitions to the 2{sub 1}{sup +}, 2{sub 2}{sup +}, 0{sub 2}{sup +}, 2{sub 3}{sup +} and 0{sub 3}{sup +} levels in {sup 100}Ru, limits are obtained at the level of ∼(0.25–1.1)⋅10{sup 22} yr.

The {beta}-decay Paul trap: A radiofrequency-quadrupole ion trap for precision {beta}-decay studies

Energy Technology Data Exchange (ETDEWEB)

Scielzo, N.D., E-mail: scielzo1@llnl.gov [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Li, G. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Department of Physics, McGill University, Montreal, Quebec, Canada H3A 2T8 (Canada); Sternberg, M.G.; Savard, G. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Department of Physics, University of Chicago, Chicago, Illinois 60637 (United States); Bertone, P.F. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Buchinger, F. [Department of Physics, McGill University, Montreal, Quebec, Canada H3A 2T8 (Canada); Caldwell, S. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Department of Physics, University of Chicago, Chicago, Illinois 60637 (United States); Clark, J.A. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Crawford, J. [Department of Physics, McGill University, Montreal, Quebec, Canada H3A 2T8 (Canada); Deibel, C.M. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824 (United States); Fallis, J. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba, Canada R3T 2N2 (Canada); Greene, J.P. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); and others

2012-07-21

The {beta}-decay Paul trap is a linear radiofrequency-quadrupole ion trap that has been developed for precision {beta}-decay studies. The design of the trap electrodes allows a variety of radiation detectors to surround the cloud of trapped ions. The momentum of the low-energy recoiling daughter nuclei following {beta} decay is negligibly perturbed by scattering and is available for study. This advantageous property of traps allows the kinematics of particles that are difficult or even impossible to directly detect to be precisely reconstructed using conservation of energy and momentum. An ion-trap system offers several advantages over atom traps, such as higher trapping efficiencies and element-independent capabilities. The first precision experiment using this system is a measurement of {beta}-decay angular correlations in the decay of {sup 8}Li performed by inferring the momentum of the neutrino from the kinematic shifts imparted to the breakup {alpha} particles. Many other {beta}-decay studies that would benefit from a determination of the nuclear recoil can be performed with this system.

Double beta decays studied by β-γ spectroscopy with a drift chamber

International Nuclear Information System (INIS)

Okada, K.; Ejiri, H.; Shibata, T.

1986-01-01

A large scale ultra low background β-γ spectrometer ELEGANTS-V for studying double beta decays(ββ) of /sup 100/Mo and/or /sup 150/Nd is designed and is now under construction. It consists of drift chambers for identification of tracks and vertex of two β-rays, thin NaI(T1) or plastic scintillators for β-rays energy and NaI(T1) counters for γ- and cosmic-rays. Specifications of the spectrometer; energy resolution, detection efficiency, possible background counting rate and available ββ sources, have been evaluated. The spectrometer has extremely high sensitivities of the neutrinoless ββ decays (0νββ), two neutrino ββ decays (2νββ) and neutrinoless ββ decays followed one boson (Majoron). It may detect 0νββ decays with half lives up to T/sub 1/2/ = 1.2- 1.7 . 10/sup 23/ year. This limit corresponds to one part of million for the Majoran neutrino mass in units of the electron mass and for the right-handed weak current in units of the left handed one

The Majorana Demonstrator: A search for neutrinoless double-beta decay of germanium-76

Science.gov (United States)

Elliott, S. R.; Abgrall, N.; Aguayo, E.; Avignone, F. T., III; Barabash, A. S.; Bertrand, F. E.; Boswell, M.; Brudanin, V.; Busch, M.; Caldwell, A. S.; Chan, Y.-D.; Christofferson, C. D.; Combs, D. C.; Detwiler, J. A.; Doe, P. J.; Efremenko, Yu.; Egorov, V.; Ejiri, H.; Esterline, J.; Fast, J. E.; Finnerty, P.; Fraenkle, F. M.; Galindo-Uribarri, A.; Giovanetti, G. K.; Goett, J.; Green, M. P.; Gruszko, J.; Guiseppe, V. E.; Gusev, K.; Hallin, A. L.; Hazama, R.; Hegai, A.; Henning, R.; Hoppe, E. W.; Howard, S.; Howe, M. A.; Keeter, K. J.; Kidd, M. F.; Kochetov, O.; Konovalov, S. I.; Kouzes, R. T.; LaFerriere, B. D.; Leon, J.; Leviner, L. E.; Loach, J. C.; MacMullin, S.; Martin, R. D.; Mertens, S.; Mizouni, L.; Nomachi, M.; Orrell, J. L.; O'Shaughnessy, C.; Overman, N. R.; Phillips, D. G., II; Poon, A. W. P.; Pushkin, K.; Radford, D. C.; Rielage, K.; Robertson, R. G. H.; Ronquest, M. C.; Schubert, A. G.; Shanks, B.; Shima, T.; Shirchenko, M.; Snavely, K. J.; Snyder, N.; Soin, A.; Strain, J.; Suriano, A. M.; Timkin, V.; Tornow, W.; Varner, R. L.; Vasilyev, S.; Vetter, K.; Vorren, K.; White, B. R.; Wilkerson, J. F.; Xu, W.; Yakushev, E.; Young, A. R.; Yu, C.-H.; Yumatov, V.

2013-12-01

The Majorana collaboration is searching for neutrinoless double beta decay using 76Ge, which has been shown to have a number of advantages in terms of sensitivities and backgrounds. The observation of neutrinoless double-beta decay would show that lepton number is violated and that neutrinos are Majorana particles and would simultaneously provide information on neutrino mass. Attaining sensitivities for neutrino masses in the inverted hierarchy region, 15 - 50 meV, will require large, tonne-scale detectors with extremely low backgrounds, at the level of ˜1 count/t-y or lower in the region of the signal. The Majorana collaboration, with funding support from DOE Office of Nuclear Physics and NSF Particle Astrophysics, is constructing the Demonstrator, an array consisting of 40 kg of p-type point-contact high-purity germanium (HPGe) detectors, of which ˜30 kg will be enriched to 87% in 76Ge. The Demonstrator is being constructed in a clean room laboratory facility at the 4850' level (4300 m.w.e.) of the Sanford Underground Research Facility (SURF) in Lead, SD. It utilizes a compact graded shield approach with the inner portion consisting of ultra-clean Cu that is being electroformed and machined underground. The primary aim of the Demonstrator is to show the feasibility of a future tonne-scale measurement in terms of backgrounds and scalability.

The double beta decay spectrum of 100Mo as measured with a TPC

International Nuclear Information System (INIS)

Elliott, S.R.; Moe, M.K.; Nelson, M.A.; Vient, M.A.

1991-01-01

A time projection chamber with 8.3 grams of enriched 100 MoO 3 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 x10 19 y at the 68% confidence level for two-neutrino double beta decay of 100 Mo. (author)

The 76Ge(n,p)76Ga reaction and its relevance to searches for the neutrino-less double-beta decay of 76Ge

Science.gov (United States)

Tornow, W.; Bhike, Megha; Fallin, B.; Krishichayan, Fnu

2015-10-01

The 76Ge(n,p)76Ga reaction and the subsequent β decay of 76Ga to 76Ge has been used to excite the 3951.9 keV state of 76Ge, which decays by emission of a 2040.7 keV γ ray. Using HPGe detectors, the associated pulse-height signal may be undistinguishable from the potential signal produced in neutrino-less double-beta decay of 76Ge with its Q-value of 2039.0 keV. In the neutron energy range between 10 and 20 MeV the production cross section of the 2040.7 keV γ ray is approximately 0.1 mb. In the same experiment γ rays of energy 2037.9 keV resulting from the 76Ge(n, γ)77Ge reaction were clearly observed. Adding the 76Ge(n,n' γ)76Ge reaction, which also produces the 2040.7 keV γ ray with a cross section value of the order of 0.1 mb clearly shows that great care has to be taken to eliminate neutron-induced backgrounds in searches for neutrino-less double-beta decay of 76Ge. This work was supported by the U.S. DOE under Grant NO. DE-FG02-97ER41033.

Results on neutrinoless double beta decay search in GERDA. Background modeling and limit setting

International Nuclear Information System (INIS)

Becerici Schmidt, Neslihan

2014-01-01

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 76 Ge by operating high purity germanium (HPGe) detectors enriched in the isotope 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 -2 cts/(keV.kg.yr) at Q 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 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 42 K decays in LAr to the background spectrum has yielded a 42 K( 42 Ar) 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 226 Ra chain indicated a total 226 Ra activity of (3.0±0.9) μBq and a total initial 210 Po 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 76 Ge has been determined as T 1/2 2ν =(1.926±0.094).10 21 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 Q ββ ±5 keV window is resulting from close

Determination of the direction to a source of antineutrinos via inverse beta decay in Double Chooz

Science.gov (United States)

Nikitenko, Ya.

2016-11-01

To determine the direction to a source of neutrinos (and antineutrinos) is an important problem for the physics of supernovae and of the Earth. The direction to a source of antineutrinos can be estimated through the reaction of inverse beta decay. We show that the reactor neutrino experiment Double Chooz has unique capabilities to study antineutrino signal from point-like sources. Contemporary experimental data on antineutrino directionality is given. A rigorous mathematical approach for neutrino direction studies has been developed. Exact expressions for the precision of the simple mean estimator of neutrinos' direction for normal and exponential distributions for a finite sample and for the limiting case of many events have been obtained.

Neutrinoless double beta decay in an SU(3)L x U(1)N model

International Nuclear Information System (INIS)

Pleitez, V.; Tonasse, M.D.

1993-01-01

A model for the electroweak interactions with SU (3) L x U(1) N gauge symmetry is considered. It is shown that, it is the conservation of F = L + B which forbids massive neutrinos and the neutrinoless double beta decay, (β β) On u. Explicit and spontaneous breaking of F imply that the neutrinos have an arbitrary mass and (β β) On u proceeds also with some contributions that do not depend explicitly on the neutrino mass. (author)

Double-beta decay: Physics beyond the standard model now and in the future (GENIUS)

International Nuclear Information System (INIS)

Klapdor-Kleingrothaus, H.V.

1998-01-01

Nuclear double beta decay has an extraordinarily broad potential in searches for physics beyond the Standard Model, probing already now the TeV scale, at which new physics is expected to manifest itself. These possibilities are reviewed here. First, the result of present-generation experiments are discussed. The most sensitive one of these, the Heidelberg-Moscow experiment at the Gran Sasso underground laboratory, probes the electron mass now in the sub-eV region and will reach a limit of some 0.1 eV in a few years. On the basis of a large amount of theoretical work done by the Heidelberg Double Beta Group in the last two years, results are obtained also for SUSY models (R-parity breaking and neutrino mass), for leptoquarks (leptoquark-Higgs boson coupling), for compositeness, for right-handed W-boson mass, and for some other problems. These results are comfortably competitive with corresponding results from high-energy accelerators like Tevatron, HERA, etc. Future prospects for ββ research are discussed. A new Heidelberg experimental proposal (GENIUS) is presented, which would make it possible to increase the sensitivity for the 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 models beyond standard. Its sensitivity for neutrino-oscillation parameters would be higher than that of all present terrestrial neutrino-oscillation experiments and that of those planned for the future. It would further, even at a first step, cover almost the full MSSM parameter space for prediction of neutralinos as cold dark matter, making the experimental competitive with LHC in searches for supersymmetry

Search for double beta decay processes of {sup 124}Xe with XENON100 and XENON1T

Energy Technology Data Exchange (ETDEWEB)

Fieguth, Alexander [IKP, Westfaelische-Wilhelms-Universitaet Muenster (Germany)

2016-07-01

Driven by the search for dark matter particles the XENON dark matter project recently installed its next stage multi-ton experiment XENON1T at the LNGS, which will probe the spin-indpendent-WIMP-Nucleon cross section down to 2.10{sup -47} cm{sup 2}. Besides its main purpose different particle physics topics can be addressed by the taken data. One example are the double beta decay processes of natural isotope {sup 124}Xe. This isotope is expected to decay via two-neutrino double electron capture (2νECEC) and due to its high Q-value of 2864 keV additionally through 2νβ{sup +}β{sup +}. Since these processes have not been detected so far, there is only a lower limit the respective half-life (e.g. > 4.7.10{sup 21} yr for 2νECEC). A detection of the 2νECEC is possible using XENON1T data by looking for its clear signature of secondary X-rays or Auger electrons and at least new lower half-life limits for all other decay channels can be obtained. While these processes are expected from standard model physics, a detection of a decay without neutrinos (e.g 0νECEC) would hint towards beyond the standard model physics and could derive conclusions on the neutrino mass. Until XENON1T is taking data, the search for all processes can be tested in the recorded data of its predecessor XENON100.

Beta decay of highly charged ions

International Nuclear Information System (INIS)

Litvinov, Yuri A; Bosch, Fritz

2011-01-01

Beta decay of highly charged ions has attracted much attention in recent years. An obvious motivation for this research is that stellar nucleosynthesis proceeds at high temperatures where the involved atoms are highly ionized. Another important reason is addressing decays of well-defined quantum-mechanical systems, such as one-electron ions where all interactions with other electrons are excluded. The largest modifications of nuclear half-lives with respect to neutral atoms have been observed in beta decay of highly charged ions. These studies can be performed solely at ion storage rings and ion traps, because there high atomic charge states can be preserved for extended periods of time (up to several hours). Currently, all experimental results available in this field originate from experiments at the heavy-ion complex GSI in Darmstadt. There, the fragment separator facility FRS allows the production and separation of exotic, highly charged nuclides, which can then be stored and investigated in the storage ring facility ESR. In this review, we present and discuss in particular two-body beta decays, namely bound-state beta decay and orbital electron capture. Although we focus on experiments conducted at GSI, we will also attempt to provide general requirements common to any other experiment in this context. Finally, we address challenging but not yet performed experiments and we give prospects for the new radioactive beam facilities, such as FAIR in Darmstadt, IMP in Lanzhou and RIKEN in Wako.

Double beta decay: Comparison of theory to experiment

International Nuclear Information System (INIS)

Haxton, W.C.

1992-01-01

I review ββ decay in the standard model and as a test of Majorana neutrino masses and right-handed couplings. A summary is given of some of the nuclear physics issues involved in evaluating 2 ν and 0ν matrix elements. Dirac and pseudoDirac limits are discussed to illustrate how quantities constrained on 0ν ββ decay depend on the parameters of the mass matrix. Implications of 0ν ββ decay for models with 17 keV neutrinos, for models with massive Majorana neutrinos, and for Majorons are discussed. It is argued that a recent remeasurement of the total ββ decay rate of 126 Te is important in constraining (nonstandard) Majoron models

A review of superheated superconducting granules as a detector for dark matter, solar neutrinos, monopoles and double beta decay

International Nuclear Information System (INIS)

Pretzl, K.P.

1987-11-01

The use of superheated superconducting granules as a particle detector is reviewed. Their application for the detection of dark matter, solar neutrinos, monopoles, and double beta decay is described. A status report on the experimental development of these devices is given. (orig.)

The search for 0νββ decay with the GERDA experiment: Status and prospects

Science.gov (United States)

Majorovits, B.

2015-08-01

The GERDA experiment is designed to search for neutrinoless double beta decay of 76Ge using HPGe detectors directly immersed into liquid argon. In its first phase the GERDA experiment has yielded a half life limit on this decay of T1/2 0 v>2.1 ṡ1025 . A background model has been developed. It explains the measured spectrum well, taking into account only components with distances to the detectors less then 2 cm. Competitive limits on Majoron accompanied double beta decay have been derived. Phase II of the experiment, now with additional liquid argon veto installed, is presently starting its commissioning phase. First commissioning spectra from calibration measurements are shown, proving that the liquid argon veto leads to a significant reduction of background events.

Results on neutrinoless double beta decay search in GERDA. Background modeling and limit setting

Energy Technology Data Exchange (ETDEWEB)

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

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

International Nuclear Information System (INIS)

Hugon, C.

2012-11-01

The NEMO3 experiment was researching the neutrinoless double-β (0ndb) decay by using various sources of double beta decay isotopes (mainly 100 Mo, 82 Se, 116 Cd and 130 Te 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 82 Se (for a sensitivity of 10 26 years). The main goal of the thesis is to measure the 2ndb and 0ndb decay of the 100 Mo to the excited state 0 1 + of the 100 Ru 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 100 Mo are for the half-lives: T(2nbd, gs)=[7.05±0.01(stat)±0.54(syst)]*10 18 years and T(2ndb, 0 1 + )=[6.15±1.1(sta)±0.78]*10 20 years. Those results are compatibles with the last ones published by the collaboration. For the 0ndb(0 1 + ), this work gave a half-life of T(0ndb, 0 1 + ) > 2.6*10 23 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)

Search for the neutrinoless double beta decay (0νββ) of {sup 76}Ge: GERDA Phase II commissioning

Energy Technology Data Exchange (ETDEWEB)

Bode, Tobias [Physik-Department E15, Technische Universitaet Muenchen (Germany); Collaboration: GERDA-Collaboration

2015-07-01

After successful completion of Phase I the Gerda (Germanium Detector Array) experiment underwent a major upgrade of the experimental apparatus. These upgrades include additional 20 kg of custom-made detectors with improved background rejection capabilities, accompanied by improved front-end electronics and an active liquid argon scintillation light veto. A sensitivity on the neutrinoless double beta decay half-life (T{sub 1/2}{sup 0ν}) of 10{sup 26} yr should be reached after a few years of data taking (Phase II). First results of Phase II commissioning and latest results from Phase I analyses are presented in this talk.

Measuring nuclear reaction cross sections to extract information on neutrinoless double beta decay

Science.gov (United States)

Cavallaro, M.; Cappuzzello, F.; Agodi, C.; Acosta, L.; Auerbach, N.; Bellone, J.; Bijker, R.; Bonanno, D.; Bongiovanni, D.; Borello-Lewin, T.; Boztosun, I.; Branchina, V.; Bussa, M. P.; Calabrese, S.; Calabretta, L.; Calanna, A.; Calvo, D.; Carbone, D.; Chávez Lomelí, E. R.; Coban, A.; Colonna, M.; D'Agostino, G.; De Geronimo, G.; Delaunay, F.; Deshmukh, N.; de Faria, P. N.; Ferraresi, C.; Ferreira, J. L.; Finocchiaro, P.; Fisichella, M.; Foti, A.; Gallo, G.; Garcia, U.; Giraudo, G.; Greco, V.; Hacisalihoglu, A.; Kotila, J.; Iazzi, F.; Introzzi, R.; Lanzalone, G.; Lavagno, A.; La Via, F.; Lay, J. A.; Lenske, H.; Linares, R.; Litrico, G.; Longhitano, F.; Lo Presti, D.; Lubian, J.; Medina, N.; Mendes, D. R.; Muoio, A.; Oliveira, J. R. B.; Pakou, A.; Pandola, L.; Petrascu, H.; Pinna, F.; Reito, S.; Rifuggiato, D.; Rodrigues, M. R. D.; Russo, A. D.; Russo, G.; Santagati, G.; Santopinto, E.; Sgouros, O.; Solakci, S. O.; Souliotis, G.; Soukeras, V.; Spatafora, A.; Torresi, D.; Tudisco, S.; Vsevolodovna, R. I. M.; Wheadon, R. J.; Yildirin, A.; Zagatto, V. A. B.

2018-02-01

Neutrinoless double beta decay (0vββ) is considered the best potential resource to access the absolute neutrino mass scale. Moreover, if observed, it will signal that neutrinos are their own anti-particles (Majorana particles). Presently, this physics case is one of the most important research “beyond Standard Model” and might guide the way towards a Grand Unified Theory of fundamental interactions. Since the 0vββ decay process involves nuclei, its analysis necessarily implies nuclear structure issues. In the NURE project, supported by a Starting Grant of the European Research Council (ERC), nuclear reactions of double charge-exchange (DCE) are used as a tool to extract information on the 0vββ Nuclear Matrix Elements. In DCE reactions and ββ decay indeed the initial and final nuclear states are the same and the transition operators have similar structure. Thus the measurement of the DCE absolute cross-sections can give crucial information on ββ matrix elements. In a wider view, the NUMEN international collaboration plans a major upgrade of the INFN-LNS facilities in the next years in order to increase the experimental production of nuclei of at least two orders of magnitude, thus making feasible a systematic study of all the cases of interest as candidates for 0vββ.

Two neutrino double-beta decay of 100Mo to the first excited 0+ state in 100Ru

International Nuclear Information System (INIS)

Barabash, A.S.; Avignone, F.T. III; Guerard, C.K.; Umatov, V.I.

1992-06-01

Double-beta decay from the ground state of 100 Mo to the O + excited state at 1,130.29 keV in 100 Ru has been observed. A sample of 956q of Mo metal powder isotopically enriched to 98.468% of 100 Mo was counted in a Marinelli geometry with a well shielded, ultralow-background germanium detector. The cascade gamma-rays at 539.53 and 590.76 keV were observed. The resulting decay half-life is 1.1 -0.2 +0.3 x 10 21 y at 68% CL

Discovery potential of xenon-based neutrinoless double beta decay experiments in light of small angular scale CMB observations

International Nuclear Information System (INIS)

Gómez-Cadenas, J.J.; Martín-Albo, J.; Vidal, J. Muñoz; Peña-Garay, C.

2013-01-01

The South Pole Telescope (SPT) has probed an expanded angular range of the CMB temperature power spectrum. Their recent analysis of the latest cosmological data prefers nonzero neutrino masses, with Σm ν = (0.32±0.11) eV. This result, if confirmed by the upcoming Planck data, has deep implications on the discovery of the nature of neutrinos. In particular, the values of the effective neutrino mass m ββ involved in neutrinoless double beta decay (ββ0ν) are severely constrained for both the direct and inverse hierarchy, making a discovery much more likely. In this paper, we focus in xenon-based ββ0ν experiments, on the double grounds of their good performance and the suitability of the technology to large-mass scaling. We show that the current generation, with effective masses in the range of 100 kg and conceivable exposures in the range of 500 kg·year, could already have a sizeable opportunity to observe ββ0ν events, and their combined discovery potential is quite large. The next generation, with an exposure in the range of 10 ton·year, would have a much more enhanced sensitivity, in particular due to the very low specific background that all the xenon technologies (liquid xenon, high-pressure xenon and xenon dissolved in liquid scintillator) can achieve. In addition, a high-pressure xenon gas TPC also features superb energy resolution. We show that such detector can fully explore the range of allowed effective Majorana masses, thus making a discovery very likely

MAJORANA Neutrinoless Double-Beta Decay DUSEL R and D. Final report

International Nuclear Information System (INIS)

Wilkerson, John F.

2009-01-01

The Majorana research and development is addressing key issues and risks related to the collaboration's goal of undertaking a search for neutrinoless double-beta decay (0νββ) in 76 Ge using an array of hyper-pure Ge-diodes (HPGe). The observation of this decay would provide critical insight into our understanding of neutrinos, yielding definitive evidence that neutrinos are Majorana particles and providing information on the absolute mass of neutrinos. Achieving sensitivities to 0νββ decay half-lives on the order of 10 26 years requires ultra-low backgrounds in the 2039 keV region where a 0νββ decay peak would be observed. The goal of our R and D program has been to demonstrate the feasibility of all components of Majorana and to provide an integrated evaluation framework, allowing for optimization of these components in terms of background, background suppression, and signal detection efficiency and acceptance. This report covers work carried out by Majorana collaboration members at the University of Washington as part of the overall Majorana collaboration activities. Specifically the Majorana group at the University of Washington was involved in moving forward on demonstrating technology for clean large-scale cryostats and mounting the HPGe crystals in low-mass holders. The UW activities included assistance in the procurement and assembly of an electroforming system for large size cryostats, and design and fabrication of prototype crystal mounting hardware.

The Search for Neutrino-less Double-Beta Decay: A Decade of Discovery or Despair?

CERN Multimedia

CERN. Geneva

2011-01-01

The search for "neutrino-less double-bete decay" decay in candidate nuclear isotopes remains a central focus in contemporary particle physics, with the main goal of establishing whether the neutrino is its own anti-particle. A positive detection would also establish the presence of lepton number violation in this decay, and suggest the existence of processes beyond the Standard Model and reach of terrestrial accelerators. With the discovery and quantitative assessment of neutrino flavor oscillation, guaranteeing the presence of a non-zero neutrino mass – a requirement for "neutrino-less double-bete decay" decay to occur – motivation has surged. In a review of the present diverse and vigorous current experimental situation, I must focus on just a few approaches and candidate isotopes, in particular on 136Xe and a new experimental effort, NEXT, exploiting the unfamiliar phenomenon of electroluminescence. But, even if the neutrino is its own anti-particle, experiments may see no decays! Stil...

The LUCIFER/CUPID-0 demonstrator: searching for the neutrinoless double-beta decay with Zn82Se scintillating bolometers

Science.gov (United States)

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. S.; Nastasi, M.; Nisi, S.; Nones, C.; 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.

2017-09-01

Future experiments on neutrinoless double beta-decay with the aim of exploring the inverted hierarchy region have to employ detectors with excellent energy resolution and zero background in the energy region of interest. Cryogenic scintillating bolometers turn out to be a suitable candidate since they offer particle discrimination: the dual channel detection of the heat and the scintillation light signal allows for particle identification. In particular such detectors permit for a suppression of α-induced backgrounds, a key-issue for next-generation tonne-scale bolometric experiments. We report on the progress and current status of the LUCIFER/CUPID-0 demonstrator, the first array of scintillating bolometers based on enriched Zn82Se crystals which is expected to start data taking in 2016 and the potential of this detection technique for a future tonne-scale bolometric experiment after CUORE.

New results for double-beta decay of 100Mo to excited final states of 100Ru using the TUNL-ITEP apparatus

International Nuclear Information System (INIS)

Kidd, M.F.; Esterline, J.H.; Tornow, W.; Barabash, A.S.; Umatov, V.I.

2009-01-01

The coincidence detection efficiency of the TUNL-ITEP apparatus designed for measuring half-life times of two-neutrino double-beta (2νββ) decay transitions to excited final states in daughter nuclei has been measured with a factor of 2.4 improved accuracy. In addition, the previous measuring time of 455 days for the study of the 100 Mo 2νββ decay to the first excited 0 1 + state in 100 Ru has been increased by 450 days, and a new result (combined with the previous measurement obtained with the same apparatus) for this transition is presented: T 1/2 =[5.5 -0.8 +1.2 (stat)±0.3(syst)]x10 20 yr. Measured 2νββ decay half-life times to excited states can be used to test the reliability of nuclear matrix element calculations needed for determining the effective neutrino mass from zero-neutrino double-beta decay data. We also present new limits for transitions to higher excited states in 100 Ru which, if improved, may be of interest for more exotic conjectures, like a bosonic component to neutrino statistics.

Can $\\beta$-decay probe excited state halos?

CERN Multimedia

2002-01-01

In the first experiment at the newly constructed ISOLDE Facility the first-forbidden $\\beta$-decay of $^{17}$Ne into the first excited state of $^{17}$F has been measured. It is a factor two faster than the corresponding mirror decay and thus gives one of the largest recorded asymmetries for $\\beta$-decays feeding bound final states. Shell-model calculations can only reproduce the asymmetry if the halo structure of the $^{17}$F state is taken into account.

Exploration of the neutrinoless double beta decay of 136Xe nucleus by the 'KamLAND-Zen' experiment. Results of the first phase and future prospect

International Nuclear Information System (INIS)

Yamada, Satoru; Shirai, Junpei

2013-01-01

Exploration of the double beta decay without neutrino production (0 ν ββ decay) has come to be considered as one of the clues to the new physics beyond the standard model in the recent years. Searching for this phenomenon is the only possible method to verify if the neutrino itself be the equal particle of the antineutrino (Majorana particle) or not. If this decay process is found, it is the discovery of the nonconservative process of the total lepton number which goes beyond the standard theory. At the same time, it confirms that the neutrinos are the Majorana particles. In addition, from the decay half-lives, the absolute value of neutrino mass and hierarchy as well as the new knowledge of the CP violation in the lepton sector are expected to be obtained. Further progress is expected toward the development of the research of the particle creation mechanism at the beginning of the universe. Strong competitions are now being developed throughout the world to become the first to discover the phenomenon to go beyond the standard theory. In this text, the underground facility of KamLAND-Zen experiment with remodeled KamLAND detector with large amount of 136 Xe isotope is introduced and the results of the data obtained and analyzed by June 2012 are reported. Future prospect is described finally. (S. Funahashi)

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

Energy Technology Data Exchange (ETDEWEB)

Ali, A. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Borisov, A.V.; Zhuridov, D.V. [Moscow State Univ. (Russian Federation). Faculty of Physics

2007-06-15

The angular correlation of the electrons emitted in the neutrinoless double beta decay (0{nu}2{beta}) 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 d{gamma}/dcos {theta} {proportional_to}(1-K cos {theta}) is essentially independent of the nuclear matrix element models and present its numerical values for the five nuclei of interest ({sup 76}Ge, {sup 82}Se, {sup 100}Mo, {sup 130}Te, and {sup 136}Xe), assuming that the 0{nu}2{beta}-decays in these nuclei are induced solely by a light Majorana neutrino, {nu}{sub M}. This coefficient varies between K=0.82 (for the {sup 76}Ge nucleus) and K=0.88 (for the {sup 82}Se and {sup 100}Mo 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 {nu}{sub M}+NP scenarios for the {sup 76}Ge nucleus. As an illustration of the correlations among the 0{nu}2{beta} observables (half-life T{sub 1/2}, 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 W{sub R}-boson mass and the left-right mixing parameter {zeta}. (orig.)

Novel field cage design for the PandaX III double beta decay experiment

Science.gov (United States)

Chaiyabin, P.; Giboni, K. L.; Han, K.; Ji, X.; Juyal, P.; Kobdaj, C.; Liu, J.; Lomon, J.; Pasaja, N.; Poolcharuansin, P.; Rujirawat, S.; Songsiriritthigul, P.; Yan, Y.; Zhao, L.

2017-10-01

PandaX III is a High Pressure gaseous xenon Time Projection Chamber for Double Beta Decay detection. It will be installed deep underground in the JinPing Laboratory in Szechuan province, China. During its first phase the detector will operate with 200 kg of enriched 136Xe. The detector consists of a mesh cathode in the center of a cylindrical vessel and Micro-Bulk Micro-Megas at both ends to read out the drifting charges. The active volume is surrounded by an array of electrodes to shape the homogeneous drift field, the so called field cage. Gaseous xenon, however, is a poor dielectric. It would require in excess of 10 cm to safely stand off the HV between these electrodes and the grounded detector walls. Nearly a quarter of our available xenon would be wasted in this dead space. In a new design the electric field outside the field shaping is totally contained in a cylinder 1.6 m diameter and 2 m long. For manufacturing two 50 mm thick Acrylic plates are bend into half cylinders and bonded together. The outside surface of the cylinder is covered with a copper mesh as ground plane. The gap between field cage and detector vessel can be now reduced to 1 mm, and this gap is field free. The amount of wasted xenon is reduced by a factor 100. The field shaping electrodes and the resistive divider network are mounted on 5 mm thick Acrylic panels suspended on the inside of the field cage. This design is realized with low radioactivity materials.

New underground neutrino observatory-GENIUS-in the new millenium for solar neutrinos, dark matter and double beta decay

CERN Document Server

Klapdor-Kleingrothaus, H V

2001-01-01

Double beta decay is indispensable to solve the question of the neutrino mass matrix together with nu oscillation experiments. The most sensitive experiment for eight years-the HEIDELBERG-MOSCOW experiment in Gran-Sasso-already now, with the experimental limit of (m/sub nu /)<0.26 eV excludes degenerate nu mass scenarios allowing neutrinos as hot dark matter in the Universe for the small angle MSW solution of the solar neutrino problem. It probes cosmological models including hot dark matter already now on the level of future satellite experiments MAP and PLANCK. It further probes many topics of beyond standard model physics at the TeV scale. Future experiments should give access to the multiTeV range and complement on many ways the search for new physics at future colliders like LHC and NLC. For neutrino physics GENIUS will allow to test almost all neutrino mass scenarios allowed by the present neutrino oscillation experiments. At the same time GENIUS will cover a wide range of the parameter space of pred...

Constraining neutrino mass from neutrinoless double beta decay

Science.gov (United States)

Dev, P. S. Bhupal; Goswami, Srubabati; Mitra, Manimala; Rodejohann, Werner

2013-11-01

We study the implications of the recent results on neutrinoless double beta decay (0νββ) from GERDA-I (Ge76) and KamLAND-Zen+EXO-200 (Xe136) and the upper limit on the sum of light neutrino masses from Planck. We show that the upper limits on the effective neutrino mass from Xe136 are stronger than those from Ge76 for most of the recent calculations of the nuclear matrix elements (NMEs). We also analyze the compatibility of these limits with the claimed observation in Ge76 and show that while the updated claim value is still compatible with the recent GERDA limit as well as the individual Xe136 limits for a few NME calculations, it is inconsistent with the combined Xe136 limit for all but one NME. Imposing the most stringent limit from Planck, we find that the canonical light neutrino contribution cannot saturate the current limit, irrespective of the NME uncertainties. Saturation can be reached by inclusion of the right-handed (RH) neutrino contributions in TeV-scale left-right symmetric models with type-II seesaw. This imposes a lower limit on the lightest neutrino mass. Using the 0νββ bounds, we also derive correlated constraints in the RH sector, complimentary to those from direct searches at the LHC.

$\\beta$-decay studies using total-absorption spectroscopy

CERN Document Server

Algora, A; García-Borge, M J; Cano-Ott, D; Collatz, R; Courtin, S; Dessagne, P; Fraile-Prieto, L M; Gadea, A; Gelletly, W; Hellström, M; Janas, Z; Jungclaus, A; Kirchner, R; Karny, M; Le Scornet, G; Miehé, C; Maréchal, F; Moroz, F; Nacher, E; Poirier, E; Roeckl, E; Rubio, B; Rykaczewski, K; Taín, J L; Tengblad, O; Wittmann, V

2004-01-01

$\\beta$-decay experiments are a primary source of information for nuclear-structure studies and at the same time complementary to in- beam investigations of nuclei far from stability. Although both types of experiment are mainly based on $\\gamma$-ray spectroscopy, they face different experimental problems. The so-called " Pandemonium effect " is a critical problem in $\\beta$-decay if we are to test theoretically calculated transition probabilities. In this contribution we will present a solution to this problem using total absorption spectroscopy methods. We will also present some examples of experiments carried out with the Total Absorption Spectrometer (TAS) at GSI and describe a new device LUCRECIA recently installed at CERN.

New approach to the search for neutrinoless double beta decay

International Nuclear Information System (INIS)

Raghavan, R.S.

1994-01-01

Sub-eV Majorana neutrino masses left-angle m ν right-angle, can be explored by a new approach to neutrinoless double β decay using 136 Xe in a Xe gas-loaded, multiton liquid scintillator installed in a very low background detector such as the Kamiokande facility. With enriched 136 Xe, a readily implementable, 10 ton detector experiment can establish an left-angle m ν right-angle=0.45 eV at 3σ in 1 yr (or exclude an left-angle m ν right-angle ν right-angle ν right-angle <1.3 eV

Results of the BiPo-1 prototype for radiopurity measurements for the SuperNEMO double beta decay source foils

Energy Technology Data Exchange (ETDEWEB)

Argyriades, J. [LAL, Universite Paris-Sud, CNRS/IN2P3, F-91405 Orsay (France); Arnold, R. [IPHC, Universite de Strasbourg, CNRS/IN2P3, F-67037 Strasbourg (France); Augier, C. [LAL, Universite Paris-Sud, CNRS/IN2P3, F-91405 Orsay (France); Baker, J. [INL, Idaho Falls, ID 83415 (United States); Barabash, A.S. [Institute of Theoretical and Experimental Physics, 117259 Moscow (Russian Federation); Basharina-Freshville, A. [University College London, WC1E 6BT London (United Kingdom); Bongrand, M.; Bourgeois, C.; Breton, D.; Briere, M.; Broudin-Bay, G. [LAL, Universite Paris-Sud, CNRS/IN2P3, F-91405 Orsay (France); Brudanin, V.B. [Joint Institute for Neear Research, 141980 Dubna (Russian Federation); Caffrey, A.J. [INL, Idaho Falls, ID 83415 (United States); Carcel, S. [Instituto de Fisica Corpuscular, CSIC, Universidad de Valencia, Valencia (Spain); Cebrian, S. [Instituto de Fisica Nuclear y Altas Energias, Universidad de Zaragoza, Zaragoza (Spain); Chapon, A. [LPC Caen, ENSICAEN, Universite de Caen, CNRS/IN2P3, F-14032 Caen (France); Chauveau, E. [CNRS/IN2P3, Centre d' Etudes Nucleaires de Bordeaux Gradignan, UMR 5797, F-33175 Gradignan (France); Universite de Bordeaux, Centre d' Etudes Nucleaires de Bordeaux Gradignan, UMR 5797, F-33175 Gradignan (France); Dafni, Th. [Instituto de Fisica Nuclear y Altas Energias, Universidad de Zaragoza, Zaragoza (Spain); Diaz, J. [Instituto de Fisica Corpuscular, CSIC, Universidad de Valencia, Valencia (Spain); Durand, D. [LPC Caen, ENSICAEN, Universite de Caen, CNRS/IN2P3, F-14032 Caen (France)

2010-10-01

The development of BiPo detectors is dedicated to the measurement of extremely high radiopurity in {sup 208}Tl and {sup 214}Bi for the SuperNEMO double beta decay source foils. A modular prototype, called BiPo-1, with 0.8 m{sup 2} of sensitive surface area, has been running in the Modane Underground Laboratory since February, 2008. The goal of BiPo-1 is to measure the different components of the background and in particular the surface radiopurity of the plastic scintillators that make up the detector. The first phase of data collection has been dedicated to the measurement of the radiopurity in {sup 208}Tl. After more than one year of background measurement, a surface activity of the scintillators of A({sup 208}Tl)=1.5{mu}Bq/m{sup 2} is reported here. Given this level of background, a larger BiPo detector having 12 m{sup 2} of active surface area, is able to qualify the radiopurity of the SuperNEMO selenium double beta decay foils with the required sensitivity of A({sup 208}Tl)<2{mu}Bq/kg (90% C.L.) with a six month measurement.

PandaX-III: Searching for neutrinoless double beta decay with high pressure 136Xe gas time projection chambers

Science.gov (United States)

Chen, Xun; Fu, ChangBo; Galan, Javier; Giboni, Karl; Giuliani, Franco; Gu, LingHui; Han, Ke; Ji, XiangDong; Lin, Heng; Liu, JiangLai; Ni, KaiXiang; Kusano, Hiroki; Ren, XiangXiang; Wang, ShaoBo; Yang, Yong; Zhang, Dan; Zhang, Tao; Zhao, Li; Sun, XiangMing; Hu, ShouYang; Jian, SiYu; Li, XingLong; Li, XiaoMei; Liang, Hao; Zhang, HuanQiao; Zhao, MingRui; Zhou, Jing; Mao, YaJun; Qiao, Hao; Wang, SiGuang; Yuan, Ying; Wang, Meng; Khan, Amir N.; Raper, Neill; Tang, Jian; Wang, Wei; Dong, JiaNing; Feng, ChangQing; Li, Cheng; Liu, JianBei; Liu, ShuBin; Wang, XiaoLian; Zhu, DanYang; Castel, Juan F.; Cebrián, Susana; Dafni, Theopisti; Garza, Javier G.; Irastorza, Igor G.; Iguaz, Francisco J.; Luzón, Gloria; Mirallas, Hector; Aune, Stephan; Berthoumieux, Eric; Bedfer, Yann; Calvet, Denis; d'Hose, Nicole; Delbart, Alain; Diakaki, Maria; Ferrer-Ribas, Esther; Ferrero, Andrea; Kunne, Fabienne; Neyret, Damien; Papaevangelou, Thomas; Sabatié, Franck; Vanderbroucke, Maxence; Tan, AnDi; Haxton, Wick; Mei, Yuan; Kobdaj, Chinorat; Yan, Yu-Peng

2017-06-01

Searching for the neutrinoless double beta decay (NLDBD) is now regarded as the topmost promising technique to explore the nature of neutrinos after the discovery of neutrino masses in oscillation experiments. PandaX-III (particle and astrophysical xenon experiment III) will search for the NLDBD of 136Xe at the China Jin Ping Underground Laboratory (CJPL). In the first phase of the experiment, a high pressure gas Time Projection Chamber (TPC) will contain 200 kg, 90% 136Xe enriched gas operated at 10 bar. Fine pitch micro-pattern gas detector (Microbulk Micromegas) will be used at both ends of the TPC for the charge readout with a cathode in the middle. Charge signals can be used to reconstruct the electron tracks of the NLDBD events and provide good energy and spatial resolution. The detector will be immersed in a large water tank to ensure 5 m of water shielding in all directions. The second phase, a ton-scale experiment, will consist of five TPCs in the same water tank, with improved energy resolution and better control over backgrounds.

Localizability of tachyonic particles and neutrinoless double beta decay

Energy Technology Data Exchange (ETDEWEB)

Jentschura, U.D. [Missouri University of Science and Technology, Department of Physics, Rolla, MO (United States); Institut fuer Theoretische Physik, Heidelberg (Germany); Wundt, B.J. [Missouri University of Science and Technology, Department of Physics, Rolla, MO (United States)

2012-02-15

The quantum field theory of superluminal (tachyonic) particles is plagued by a number of problems, which include the Lorentz non-invariance of the vacuum state, the ambiguous separation of the field operator into creation and annihilation operators under Lorentz transformations, and the necessity of a complex reinterpretation principle for quantum processes. Another unsolved question concerns the treatment of subluminal components of a tachyonic wave packet in the field-theoretical formalism, and the calculation of the time-ordered propagator. After a brief discussion on related problems, we conclude that rather painful choices have to be made in order to incorporate tachyonic spin- (1)/(2) particles into field theory. We argue that the field theory needs to be formulated such as to allow for localizable tachyonic particles, even if that means that a slight unitarity violation is introduced into the S matrix, and we write down field operators with unrestricted momenta. We find that once these choices have been made, the propagator for the neutrino field can be given in a compact form, and the left-handedness of the neutrino as well as the right-handedness of the antineutrino follow naturally. Consequences for neutrinoless double beta decay and superluminal propagation of neutrinos are briefly discussed. (orig.)

Localizability of tachyonic particles and neutrinoless double beta decay

International Nuclear Information System (INIS)

Jentschura, U.D.; Wundt, B.J.

2012-01-01

The quantum field theory of superluminal (tachyonic) particles is plagued by a number of problems, which include the Lorentz non-invariance of the vacuum state, the ambiguous separation of the field operator into creation and annihilation operators under Lorentz transformations, and the necessity of a complex reinterpretation principle for quantum processes. Another unsolved question concerns the treatment of subluminal components of a tachyonic wave packet in the field-theoretical formalism, and the calculation of the time-ordered propagator. After a brief discussion on related problems, we conclude that rather painful choices have to be made in order to incorporate tachyonic spin- (1)/(2) particles into field theory. We argue that the field theory needs to be formulated such as to allow for localizable tachyonic particles, even if that means that a slight unitarity violation is introduced into the S matrix, and we write down field operators with unrestricted momenta. We find that once these choices have been made, the propagator for the neutrino field can be given in a compact form, and the left-handedness of the neutrino as well as the right-handedness of the antineutrino follow naturally. Consequences for neutrinoless double beta decay and superluminal propagation of neutrinos are briefly discussed. (orig.)

Consistency check of pulse shape discrimination for broad energy germanium detectors using double beta decay data

Energy Technology Data Exchange (ETDEWEB)

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.

Searches for massive neutrinos in nuclear beta decay

International Nuclear Information System (INIS)

Jaros, J.A.

1992-10-01

The status of searches for massive neutrinos in nuclear beta decay is reviewed. The claim by an ITEP group that the electron antineutrino mass > 17eV has been disputed by all the subsequent experiments. Current measurements of the tritium beta spectrum limit m bar νe < 10 eV. The status of the 17 keV neutrino is reviewed. The strong null results from INS Tokyo and Argonne, and deficiencies in the experiments which reported positive effects, make it unreasonable to ascribe the spectral distortions seen by Simpson, Hime, and others to a 17keV neutrino. Several new ideas on how to search for massive neutrinos in nuclear beta decay are discussed

Tests of the standard electroweak model in beta decay

Energy Technology Data Exchange (ETDEWEB)

Severijns, N.; Beck, M. [Universite Catholique de Louvain (UCL), Louvain-la-Neuve (Belgium); Naviliat-Cuncic, O. [Caen Univ., CNRS-ENSI, 14 (France). Lab. de Physique Corpusculaire

2006-05-15

We review the current status of precision measurements in allowed nuclear beta decay, including neutron decay, with emphasis on their potential to look for new physics beyond the standard electroweak model. The experimental results are interpreted in the framework of phenomenological model-independent descriptions of nuclear beta decay as well as in some specific extensions of the standard model. The values of the standard couplings and the constraints on the exotic couplings of the general beta decay Hamiltonian are updated. For the ratio between the axial and the vector couplings we obtain C{sub A},/C{sub V} = -1.26992(69) under the standard model assumptions. Particular attention is devoted to the discussion of the sensitivity and complementarity of different precision experiments in direct beta decay. The prospects and the impact of recent developments of precision tools and of high intensity low energy beams are also addressed. (author)

Tests of the standard electroweak model in beta decay

International Nuclear Information System (INIS)

Severijns, N.; Beck, M.; Naviliat-Cuncic, O.

2006-05-01

We review the current status of precision measurements in allowed nuclear beta decay, including neutron decay, with emphasis on their potential to look for new physics beyond the standard electroweak model. The experimental results are interpreted in the framework of phenomenological model-independent descriptions of nuclear beta decay as well as in some specific extensions of the standard model. The values of the standard couplings and the constraints on the exotic couplings of the general beta decay Hamiltonian are updated. For the ratio between the axial and the vector couplings we obtain C A ,/C V = -1.26992(69) under the standard model assumptions. Particular attention is devoted to the discussion of the sensitivity and complementarity of different precision experiments in direct beta decay. The prospects and the impact of recent developments of precision tools and of high intensity low energy beams are also addressed. (author)

${\\beta}$-decay studies of neutron-rich $^{61-70}$Mn isotopes with the new LISOL ${\\beta}$-decay setup

CERN Multimedia

Diriken, J V J

2008-01-01

The aim of this proposal is to gather new information that will serve as benchmark to test shell model calculations in the region below $^{68}$Ni, where proper residual interactions are still under development. More specifically, the ${\\beta}$-decay experiment of the $^{61-70}$Mn isotopes will highlight the development of collectivity in the Fe isotopes and its daughters. At ISOLDE, neutron-rich Mn isotopes are produced with a UC$_{x}$ target and selective laser ionization. These beams are particularly pure and reasonable yields are obtained for the neutron-rich short lived $^{61-70}$Mn isotopes. We propose to perform ${\\beta}$-decay studies on $^{61-70}$Mn utilizing the newly-developed "LISOL ${\\beta}$-decay setup", consisting of two MINIBALL cluster Ge detectors and a standard tape station. The use of digital electronics in the readout of these detectors enables us to perform a "slow correlation technique" which should indicate the possible existence of isomers in the daughter nuclei.

Limits on neutrino-less double beta decay of 100Mo

International Nuclear Information System (INIS)

Ejiri, H.; Fushimi, K.; Hayashi, K.; Kishimoto, T.; Kudomi, N.; Ohsumi, H.; Okada, K.; Shima, T.; Tanaka, J.

1996-01-01

Exclusive measurements of neutrino-less double beta decays (0νββ) of 100 Mo were made by means of ELEGANT V. Most stringent lower limits on the half-lives for the ground-state transition were obtained for the 0νββ processes as T 1/2 0ν (m ν ) > 5.2 x 10 22 y, T 1/2 0ν (λ) > 3.9 x 10 22 y and T 1/2 0ν (η) > 5.1 x 10 22 y, for the mass term left angle m ν right angle, for the right-handed current terms of left angle λ right angle and left angle η right angle, respectively, and as T 1/2 0νB > 5.4 x 10 21 y for the process (0νββB) followed by a Majoron (B). These limits lead to the upper limits of left angle m ν right angle -6 , left angle η right angle -8 and left angle g B right angle -5 with g B being the coupling of B with the neutrino field. Limits on other possible processes beyond the standard theory are discussed. (orig.)

Time reversal violation in radiative beta decay: experimental plans

Science.gov (United States)

Behr, J. A.; McNeil, J.; Anholm, M.; Gorelov, A.; Melconian, D.; Ashery, D.

2017-01-01

Some explanations for the excess of matter over antimatter in the universe involve sources of time reversal violation (TRV) in addition to the one known in the standard model of particle physics. We plan to search for TRV in a correlation between the momenta of the beta, neutrino, and the radiative gamma sometimes emitted in nuclear beta decay. Correlations involving three (out of four) momenta are sensitive at lowest order to different TRV physics than observables involving spin, such as electric dipole moments and spin-polarized beta decay correlations. Such experiments have been done in radiative kaon decay, but not in systems involving the lightest generation of quarks. An explicit low-energy physics model being tested produces TRV effects in the Fermi beta decay of the neutron, tritium, or some positron-decaying isotopes. We will present plans to measure the TRV asymmetry in radiative beta decay of laser-trapped 38mK at better than 0.01 sensitivity, including suppression of background from positron annihilation. Supported by NSERC, D.O.E., Israel Science Foundation. TRIUMF receives federal funding via a contribution agreement with the National Research Council of Canada.

GERDA results and the future perspectives for the neutrinoless double beta decay search using 76Ge

Science.gov (United States)

Agostini, M.; Bakalyarov, A. M.; Balata, M.; Barabanov, I.; Baudis, L.; Bauer, C.; Bellotti, E.; Belogurov, S.; Bettini, A.; Bezrukov, L.; Biernat, J.; Bode, T.; Borowicz, D.; Brudanin, V.; Brugnera, R.; Caldwell, A.; Cattadori, C.; Chernogorov, A.; Comellato, T.; D’Andrea, V.; Demidova, E. V.; di Marco, N.; Domula, A.; Doroshkevich, E.; Egorov, V.; Gangapshev, A.; Garfagnini, A.; Giordano, M.; Grabmayr, P.; Gurentsov, V.; Gusev, K.; Hakenmüller, J.; Heisel, M.; Hemmer, S.; Hiller, R.; Hofmann, W.; Hult, M.; Inzhechik, L. V.; Janicskó Csáthy, J.; Jochum, J.; Junker, M.; Kazalov, V.; Kermaidic, Y.; Kihm, T.; Kirpichnikov, I. V.; Kirsch, A.; Klimenko, A.; Kneißl, R.; Knöpfle, K. T.; Kochetov, O.; Kornoukhov, V. N.; Kuzminov, V. V.; Laubenstein, M.; Lazzaro, A.; Lindner, M.; Lippi, I.; Lubashevskiy, A.; Lubsandorzhiev, B.; Lutter, G.; Macolino, C.; Majorovits, B.; Maneschg, W.; Miloradovic, M.; Mingazheva, R.; Misiaszek, M.; Moseev, P.; Nemchenok, I.; Panas, K.; Pandola, L.; Pelczar, K.; Pertoldi, L.; Pullia, A.; Ransom, C.; Riboldi, S.; Rumyantseva, N.; Sada, C.; Salamida, F.; Schneider, B.; Schönert, S.; Schreiner, J.; Schütz, A.-K.; Schulz, O.; Schwingenheuer, B.; Selivanenko, O.; Shevchik, E.; Shirchenko, M.; Simgen, H.; Smolnikov, A.; Stanco, L.; Vanhoefer, L.; Vasenko, A. A.; Veresnikova, A.; von Sturm, K.; Wagner, V.; Wegmann, A.; Wester, T.; Wiesinger, C.; Wojcik, M.; Yanovich, E.; Zhitnikov, I.; Zhukov, S. V.; Zinatulina, D.; Zschocke, A.; Zsigmond, A. J.; Zuber, K.; Zuzel, G.

2018-03-01

The GERmanium Detector Array (GERDA) is a low background experiment at the Laboratori Nazionali del Gran Sasso (LNGS) of INFN designed to search for the rare neutrinoless double beta decay (0νββ) of 76Ge. In the first phase (Phase I) of the experiment, high purity germanium diodes were operated in a “bare” mode and immersed in liquid argon. The overall background level of 10‑2cts/(keV ṡkg ṡyr) was a factor of ten better than those of its predecessors. No signal was found and a lower limit was set on the half-life for the 0νββ decay of 76Ge T1/20ν > 2.1 × 1025 yr (90% CL), while the corresponding median sensitivity was 2.4 × 1025 yr (90% CL). A second phase (Phase II) started at the end of 2015 after a major upgrade. Thanks to the increased detector mass and performance of the enriched germanium diodes and due to the introduction of liquid argon instrumentation techniques, it was possible to reduce the background down to 10‑3cts/(keV ṡkg ṡyr). After analyzing 23.2 kgṡyr of these new data no signal was seen. Combining these with the data from Phase I a stronger half-life limit of the 76Ge 0νββ decay was obtained: T1/20ν > 8.0 × 1025 yr (90% CL), reaching a sensitivity of 5.8 × 1025 yr (90% CL). Phase II will continue for the collection of an exposure of 100 kg ṡyr. If no signal is found by then the GERDA sensitivity will have reached 1.4 × 1026 yr for setting a 90% CL. limit. After the end of GERDA Phase II, the flagship experiment for the search of 0νββ decay of 76Ge will be LEGEND. LEGEND experiment is foreseen to deploy up to 1-ton of 76Ge. After ten years of data taking, it will reach a sensitivity beyond 1028 yr, and hence fully cover the inverted hierarchy region.

Induced Double-Beta Processes in Electron Fluxes as Resonance Reactions in Weak Interaction

International Nuclear Information System (INIS)

Gaponov, Yu.V.

2004-01-01

A theory of induced double-beta processes in electron beams is developed. It is shown that a resonance mechanism of the excitation of the ground state of an intermediate nucleus is realized in them, this mechanism being described in the single-state-dominance approximation, where the process in question is broken down into two stages, the excitation of a dominant state and its decay. This approximation is valid irrespective of the features of this state, both for allowed (for a 1 + state of the intermediate nucleus) and for forbidden transitions. An analysis of the resonance mechanism reveals that its inclusion in double-beta-decay processes requires introducing additional diagrams that describe the gamma decay of virtual intermediate states. The inclusion of such corrections may lead to a decrease in the expected half-life and to a change in the beta spectrum. Effects associated with the interference between the two stages of a double-beta process are estimated, and it is shown that their influence can be significant if the time interval between these stages is less than or on the order of the lifetime of the dominant state

Double beta decay of Uranium-238: Proton reactions of 238U in 5--12 MeV range. Final report, April 15, 1987--March 31, 1992

International Nuclear Information System (INIS)

Turkevich, A.; Economou, T.E.

1993-01-01

This report is in two parts. The first part reports on the experimental work determining the half-life for double beta decay of 238 U to 238 PU to be (2.0 ± 0.6) x 10 21 years. This is the first evidence for a third mode of decay of this heaviest naturally occurring nucleus. This rate is about 10 6 times slower than spontaneous fission, which itself is about 10 6 times slower than alpha decay. The implication of this double beta decay to neutrino masses depends on uncertain theoretical calculations of the rate for such a heavy nucleus. The second part reports on yields of principal fission products from 5.6, 7.3, 9.4, and 11.5 MeV proton interactions with 238 U. The yields at 11.5 MeV are similar to those from 14 MeV neutron fission of 238 U. At the same time, the production cross sections of 238 Np at the same energies are determined. This nuclide is produced as often as fission at the lowest energy but only 3.8% as often at the highest energy

Search for evidence of lepton number violation by neutrinoless double beta decay process from 82Se and 150Nd in NEMO-3 experiment: Bi-Po decay study from thoron chain

International Nuclear Information System (INIS)

Lemiere, Y.

2008-09-01

The NEMO-3 experiment searches for a neutrinoless double beta decay signal (ββ0ν) with an expected sensitivity in terms of the half-life limit of the order of 10 24 years. The discovery of this signal, forbidden in the Standard Model, would imply the violation of leptonic number conservation and would allow to determine the nature of this particle (Dirac or Majorana) and measure the neutrino mass scale. The goal of this work is to study high energy events from 82 Se and 150 Nd ββ decay used in NEMO-3 detector. The first part of this work consists in the elaboration of a background model using NEMO-3 data. In the second part, the ββ2ν half-life and a lower limit of the ββ0ν half-life are computed using massive Majorana neutrino exchange hypothesis, we have got: T(0ν) > 1.44*10 22 years for 150 Nd and T(0ν) > 1.82*10 23 years for 82 Se. The upper limits for the effective mass of the Majorana neutrinos are also computed, we obtain: m ββ 150 Nd and m ββ 82 Se. In the last part, the measurement of some specific thallium contamination is performed thanks to the NEMO-3 capability to detect the 212 Bi-Po decay. The measured value of the surface contamination of the calorimeter is about (150 ± 30) μBq/m 3 . So the surface contamination is too low to intervene in the data analysis of NEMO-3 but appears important for next generation scintillators

Future of neutrino experiments

Indian Academy of Sciences (India)

them are under construction. The next generation double beta decay experiments are sensitive to the inverted mass hierarchy. In order to explore the normal mass hierarchy, the sensitivity of the experiments still needs to be improved substantially. For example, see [32] for more details of the double beta decay experiments.

Neutrinoless double beta decay in chiral effective field theory: lepton number violation at dimension seven

Science.gov (United States)

Cirigliano, V.; Dekens, W.; de Vries, J.; Graesser, M. L.; Mereghetti, E.

2017-12-01

We analyze neutrinoless double beta decay (0 νββ) within the framework of the Standard Model Effective Field Theory. Apart from the dimension-five Weinberg operator, the first contributions appear at dimension seven. We classify the operators and evolve them to the electroweak scale, where we match them to effective dimension-six, -seven, and -nine operators. In the next step, after renormalization group evolution to the QCD scale, we construct the chiral Lagrangian arising from these operators. We develop a power-counting scheme and derive the two-nucleon 0 νββ currents up to leading order in the power counting for each lepton-number-violating operator. We argue that the leading-order contribution to the decay rate depends on a relatively small number of nuclear matrix elements. We test our power counting by comparing nuclear matrix elements obtained by various methods and by different groups. We find that the power counting works well for nuclear matrix elements calculated from a specific method, while, as in the case of light Majorana neutrino exchange, the overall magnitude of the matrix elements can differ by factors of two to three between methods. We calculate the constraints that can be set on dimension-seven lepton-number-violating operators from 0 νββ experiments and study the interplay between dimension-five and -seven operators, discussing how dimension-seven contributions affect the interpretation of 0 νββ in terms of the effective Majorana mass m ββ .

Neutrino nuclear responses for double beta decays and astro neutrinos by charge exchange reactions

Science.gov (United States)

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.

Minimally allowed neutrinoless double beta decay rates within an anarchical framework

International Nuclear Information System (INIS)

Jenkins, James

2009-01-01

Neutrinoless double beta decay (ββ0ν) is the only realistic probe of the Majorana nature of the neutrino. In the standard picture, its rate is proportional to m ee , the e-e element of the Majorana neutrino mass matrix in the flavor basis. I explore minimally allowed m ee values within the framework of mass matrix anarchy where neutrino parameters are defined statistically at low energies. Distributions of mixing angles are well defined by the Haar integration measure, but masses are dependent on arbitrary weighting functions and boundary conditions. I survey the integration measure parameter space and find that for sufficiently convergent weightings, m ee is constrained between (0.01-0.4) eV at 90% confidence. Constraints from neutrino mixing data lower these bounds. Singular integration measures allow for arbitrarily small m ee values with the remaining elements ill-defined, but this condition constrains the flavor structure of the model's ultraviolet completion. ββ0ν bounds below m ee ∼5x10 -3 eV should indicate symmetry in the lepton sector, new light degrees of freedom, or the Dirac nature of the neutrino.

The effective neutrino mass of neutrinoless double-beta decays: how possible to fall into a well

Energy Technology Data Exchange (ETDEWEB)

Xing, Zhi-zhong [University of Chinese Academy of Sciences, Institute of High Energy Physics and School of Physical Sciences, Beijing (China); Peking University, Center of High Energy Physics, Beijing (China); Zhao, Zhen-hua [Liaoning Normal University, Department of Physics, Dalian (China)

2017-03-15

The neutrinoless double-beta (0ν2β) decay is currently the only feasible process in particle and nuclear physics to probe whether massive neutrinos are the Majorana fermions. If they are of a Majorana nature and have a normal mass ordering, the effective neutrino mass term left angle m right angle {sub ee} of a 0ν2β decay may suffer significant cancellations among its three components and thus sink into a decline, resulting in a ''well'' in the three-dimensional graph of vertical stroke left angle m right angle {sub ee} vertical stroke against the smallest neutrino mass m{sub 1} and the relevant Majorana phase ρ. We present a new and complete analytical understanding of the fine issues inside such a well, and identify a novel threshold of vertical stroke left angle m right angle {sub ee} vertical stroke in terms of the neutrino masses and flavor mixing angles: vertical stroke left angle m right angle {sub ee} vertical stroke {sub *} = m{sub 3}sin{sup 2}θ{sub 13} in connection with tanθ{sub 12} = √(m{sub 1}/m{sub 2}) and ρ = π. This threshold point, which links the local minimum and maximum of vertical stroke left angle m right angle {sub ee} vertical stroke, can be used to signify observability or sensitivity of the future 0ν2β-decay experiments. Given current neutrino oscillation data, the possibility of vertical stroke left angle m right angle {sub ee} vertical stroke < vertical stroke left angle m right angle {sub ee} vertical stroke {sub *} is found to be very small. (orig.)

The Majorana project: sup 7 sup 6 Ge 0 nu beta beta-decay neutrino mass measurement

CERN Document Server

Aalseth, C E

2002-01-01

Interest in, and the relevance of, next-generation 0 nu beta beta-decay experiments is increasing. Even with nonzero neutrino mass strongly suggested by SNO, Super Kamiokande, and similar experiments sensitive to delta m sup 2 , 0 nu beta beta-decay experiments are still the only way to establish the Dirac or Majorana nature of neutrinos by measuring effective electron neutrino mass, . Various theorists have recently argued in favor of a neutrino mass between 0.01 and 1 eV. The Majorana Project aims to probe this effective neutrino mass range, reaching a sensitivity of 0.02-0.07 eV. The experiment relies entirely on proven technology and has been devised based upon the materials, technology, and data analysis demonstrated to produce the lowest background per kilogram of fiducial germanium. The project plan includes 500 kg of germanium detector material enriched to 85% in sup 7 sup 6 Ge, specialized pulse-acquisition electronics and detector segmentation for background rejection, and underground electroformed ...

$\\beta$-decay studies using total absorption techniques some recent results

CERN Document Server

Algora, A; García-Borge, M J; Cano-Ott, D; Collatz, R; Courtin, S; Dessagne, P; Fraile-Prieto, L M; Gadea, A; Gelletly, W; Hellström, M; Janas, Z; Jungclaus, A; Karny, M; Kirchner, R; Maréchal, F; Miehé, C; Moroz, F; Nacher, E; Poirier, E; Roeckl, E; Rubio, B; Rykaczewski, K; Scornet, G L; Taín, J L; Tengblad, O; Wittmann, V

2004-01-01

$\\beta$-decay experiments, are a primary source of information for nuclear structure studies and at the same time complementary to in-beam investigations far from stability. Although both types of experiment are mainly based on $\\gamma$-ray spectroscopy, they face different experimental problems. The so-called $\\textit{Pandemonium effect}$ is a critical problem in $\\beta$-decay. In this contribution we will present a solution to this problem using total absorption spectroscopy methods. We will also present some examples of experiments carried out with the total absorption spectrometers TAS at GSI and Lucrecia recently installed at CERN. (25 refs).

Beta-decay studies using total absorption techniques: some recent results

Energy Technology Data Exchange (ETDEWEB)

Algora, A.; Rubio, B.; Nacher, E.; Cano O, D.; Tain, J.L.; Gadea, A. [lnstituto de Fisica Corpuscular, Apartado Oficial 22085, 46071 Valencia (Spain); Batist, L.; Moroz, F.; Wittmann, V. [St. Petersburg Nuclear Physics Institute, RU-188-350 Gatchina, (Russian Federation); Borge, M.J.G.; Jungclaus, A.; Tengblad, O. [Instituto Estructura de la Materia, E-28006 Madrid (Spain); Collatz, R.; Hellstrom, M.; Kirchner, R.; Roeckl, E. [Gesellschaft fur Schwerionenforschung, D-64291 Darmstadt (Germany); Courtin, H.; Dessagne, Ph.; Miehe, C.; Marechal, F.; Poirier, E. [lnstitut de Recherches Subatomiques, IN2P3-CNRS, F-67037 Strassbourg Cedex 2 (France); Fraile, L.M. [ISOLDE, Division EP, CERN, CH-1211 Geneva (Switzerland); Gelletly, W. [University of Surrey, Guildford GU2 7XH (United Kingdom); Janas, Z.; Karny, M.; Rykaczewski, K. [University of Warsaw, PL-00-681, Warsaw (Poland); Le Scornet, G. [CSNSM, 91405 Orsay (France)

2004-12-01

Beta-decay experiments are a primary source of information for nuclear structure studies and at the same time complementary to in-beam investigations far from stability. Although both types of experiment are mainly based on {gamma} ray spectroscopy, they face different experimental problems. The so called Pandemonium effect [1] is a critical problem in {beta}-decay. In this contribution we will present a solution to this problem using total absorption spectroscopy methods. We will also present some examples of experiments carried out with the total absorption spectrometers TAS at GSI and Lucrecia recently installed at CERN. (Author) 25 refs., 4 figs.

Beta decay of polarized nuclei and the decay asymmetry of 8Li

International Nuclear Information System (INIS)

Bigelow, R.; Freedman, S.J.; Napolitano, J.; Quin, P.A.

1985-01-01

Under certain conditions, it is possible to produce vector-polarized radioactive nuclei in reactions with a polarized projectile and an unpolarized target. Using the intense polarized beams at the University of Wisconsin, the authors have begun a program to study the weak interaction through the beta decay of polarized nuclei produced in this way. Such experiments bear on tests of CVC in light nuclei, sensitive searches for second-class weak currents, and measurements of the weak vector-coupling constant. One may also deduce the values of certain matrix elements. Our effort is presently centering on a study of the energy dependence of the beta-decay asymmetry of 8 Li

Future prospects of baryon istability search in p-decay and n n(bar) oscillation experiments

Energy Technology Data Exchange (ETDEWEB)

Ball, S.J.; Kamyshkov, Y.A. [ed.

1996-11-01

These proceedings contain thirty-one papers which review both the theoretical and the experimental status and near future of baryon instability research. Baryon instability is investigated from the vantage point of supersymmetric and unified theories. The interplay between baryogenesis and antimatter is examined. Double beta decay experiments are discussed. The huge Icarus experiment is described with its proton decay capabilities. Neutron-antineutron oscillations investigations are presented, especially efforts with ultra-cold neutrons. Individual papers are indexed separately on the Energy Data Base.

Two-neutrino double-beta decay

International Nuclear Information System (INIS)

Guerard, O.

1992-01-01

Two previous independent reports of 2νββ-decay by the ITEP-YPI collaboration, T 2ν 1/2 = (9 ± 1) x 10 20 yr (1σ), were confirmed using a 0.25 Kg Ge(Li) detector isotopically enriched to 86% in 76 Ge. The detector was operated in the PNL-USC ultralow background facility in the Homestake gold mine for 168 days. Following a single correction to the data, a spectrum resembling that of the earlier PNL-USC experiment, with about the same intensity per 76 Ge atom, per year, was observed with a measured half life of T 2ν 1/2 = (9.2 +0.7 -0.2 ) x 10 21 y (90% C.L.), by observing the 590.76 and 539.53 keV gamma rays emitted in the 0 + 1 → 2 + → 0 + de-excitation cascade. A review of the most relevant nuclear structure calculations is given, and their predictions are compared to the measurements from the present two experiments

Determination of $\\gamma$ and $-2\\beta_s$ from charmless two-body decays of beauty mesons

CERN Document Server

Aaij, Roel; Adeva, Bernardo; Adinolfi, Marco; Affolder, Anthony; Ajaltouni, Ziad; Akar, Simon; Albrecht, Johannes; Alessio, Federico; Alexander, Michael; Ali, Suvayu; Alkhazov, Georgy; Alvarez Cartelle, Paula; Alves Jr, Antonio Augusto; Amato, Sandra; Amerio, Silvia; Amhis, Yasmine; An, Liupan; Anderlini, Lucio; Anderson, Jonathan; Andreassen, Rolf; Andreotti, Mirco; Andrews, Jason; Appleby, Robert; Aquines Gutierrez, Osvaldo; Archilli, Flavio; Artamonov, Alexander; Artuso, Marina; Aslanides, Elie; Auriemma, Giulio; Baalouch, Marouen; Bachmann, Sebastian; Back, John; Badalov, Alexey; Baesso, Clarissa; Baldini, Wander; Barlow, Roger; Barschel, Colin; Barsuk, Sergey; Barter, William; Batozskaya, Varvara; Battista, Vincenzo; Bay, Aurelio; Beaucourt, Leo; Beddow, John; Bedeschi, Franco; Bediaga, Ignacio; Belogurov, Sergey; Belous, Konstantin; Belyaev, Ivan; Ben-Haim, Eli; Bencivenni, Giovanni; Benson, Sean; Benton, Jack; Berezhnoy, Alexander; Bernet, Roland; Bettler, Marc-Olivier; van Beuzekom, Martinus; Bien, Alexander; Bifani, Simone; Bird, Thomas; Bizzeti, Andrea; Bjørnstad, Pål Marius; Blake, Thomas; Blanc, Frédéric; Blouw, Johan; Blusk, Steven; Bocci, Valerio; Bondar, Alexander; Bondar, Nikolay; Bonivento, Walter; Borghi, Silvia; Borgia, Alessandra; Borsato, Martino; Bowcock, Themistocles; Bowen, Espen Eie; Bozzi, Concezio; Brambach, Tobias; Bressieux, Joël; Brett, David; Britsch, Markward; Britton, Thomas; Brodzicka, Jolanta; Brook, Nicholas; Brown, Henry; Bursche, Albert; Busetto, Giovanni; Buytaert, Jan; Cadeddu, Sandro; Calabrese, Roberto; Calvi, Marta; Calvo Gomez, Miriam; Campana, Pierluigi; Campora Perez, Daniel; Carbone, Angelo; Carboni, Giovanni; Cardinale, Roberta; Cardini, Alessandro; Carson, Laurence; Carvalho Akiba, Kazuyoshi; Casse, Gianluigi; Cassina, Lorenzo; Castillo Garcia, Lucia; Cattaneo, Marco; Cauet, Christophe; Cenci, Riccardo; Charles, Matthew; Charpentier, Philippe; Chefdeville, Maximilien; Chen, Shanzhen; Cheung, Shu-Faye; Chiapolini, Nicola; Chrzaszcz, Marcin; Ciba, Krzystof; Cid Vidal, Xabier; Ciezarek, Gregory; Clarke, Peter; Clemencic, Marco; Cliff, Harry; Closier, Joel; Coco, Victor; Cogan, Julien; Cogneras, Eric; Cojocariu, Lucian; Collins, Paula; Comerma-Montells, Albert; Contu, Andrea; Cook, Andrew; Coombes, Matthew; Coquereau, Samuel; Corti, Gloria; Corvo, Marco; Counts, Ian; Couturier, Benjamin; Cowan, Greig; Craik, Daniel Charles; Cruz Torres, Melissa Maria; Cunliffe, Samuel; Currie, Robert; D'Ambrosio, Carmelo; Dalseno, Jeremy; David, Pascal; David, Pieter; Davis, Adam; De Bruyn, Kristof; De Capua, Stefano; De Cian, Michel; De Miranda, Jussara; De Paula, Leandro; De Silva, Weeraddana; De Simone, Patrizia; Decamp, Daniel; Deckenhoff, Mirko; Del Buono, Luigi; Déléage, Nicolas; Derkach, Denis; Deschamps, Olivier; Dettori, Francesco; Di Canto, Angelo; Dijkstra, Hans; Donleavy, Stephanie; Dordei, Francesca; Dorigo, Mirco; Dosil Suárez, Alvaro; Dossett, David; Dovbnya, Anatoliy; Dreimanis, Karlis; Dujany, Giulio; Dupertuis, Frederic; Durante, Paolo; Dzhelyadin, Rustem; Dziurda, Agnieszka; Dzyuba, Alexey; Easo, Sajan; Egorychev, Victor; Eidelman, Semen; Eisenhardt, Stephan; Eitschberger, Ulrich; Ekelhof, Robert; Eklund, Lars; El Rifai, Ibrahim; Elsasser, Christian; Ely, Scott; Esen, Sevda; Evans, Hannah Mary; Evans, Timothy; Falabella, Antonio; Färber, Christian; Farinelli, Chiara; Farley, Nathanael; Farry, Stephen; Fay, Robert; Ferguson, Dianne; Fernandez Albor, Victor; Ferreira Rodrigues, Fernando; Ferro-Luzzi, Massimiliano; Filippov, Sergey; Fiore, Marco; Fiorini, Massimiliano; Firlej, Miroslaw; Fitzpatrick, Conor; Fiutowski, Tomasz; Fol, Philip; Fontana, Marianna; Fontanelli, Flavio; Forty, Roger; Francisco, Oscar; Frank, Markus; Frei, Christoph; Frosini, Maddalena; Fu, Jinlin; Furfaro, Emiliano; Gallas Torreira, Abraham; Galli, Domenico; Gallorini, Stefano; Gambetta, Silvia; Gandelman, Miriam; Gandini, Paolo; Gao, Yuanning; García Pardiñas, Julián; Garofoli, Justin; Garra Tico, Jordi; Garrido, Lluis; Gaspar, Clara; Gauld, Rhorry; Gavardi, Laura; Gavrilov, Gennadii; Geraci, Angelo; Gersabeck, Evelina; Gersabeck, Marco; Gershon, Timothy; Ghez, Philippe; Gianelle, Alessio; Gianì, Sebastiana; Gibson, Valerie; Giubega, Lavinia-Helena; Gligorov, Vladimir; Göbel, Carla; Golubkov, Dmitry; Golutvin, Andrey; Gomes, Alvaro; Gotti, Claudio; Grabalosa Gándara, Marc; Graciani Diaz, Ricardo; Granado Cardoso, Luis Alberto; Graugés, Eugeni; Graziani, Giacomo; Grecu, Alexandru; Greening, Edward; Gregson, Sam; Griffith, Peter; Grillo, Lucia; Grünberg, Oliver; Gui, Bin; Gushchin, Evgeny; Guz, Yury; Gys, Thierry; Hadjivasiliou, Christos; Haefeli, Guido; Haen, Christophe; Haines, Susan; Hall, Samuel; Hamilton, Brian; Hampson, Thomas; Han, Xiaoxue; Hansmann-Menzemer, Stephanie; Harnew, Neville; Harnew, Samuel; Harrison, Jonathan; He, Jibo; Head, Timothy; Heijne, Veerle; Hennessy, Karol; Henrard, Pierre; Henry, Louis; Hernando Morata, Jose Angel; van Herwijnen, Eric; Heß, Miriam; Hicheur, Adlène; Hill, Donal; Hoballah, Mostafa; Hombach, Christoph; Hulsbergen, Wouter; Hunt, Philip; Hussain, Nazim; Hutchcroft, David; Hynds, Daniel; Idzik, Marek; Ilten, Philip; Jacobsson, Richard; Jaeger, Andreas; Jalocha, Pawel; Jans, Eddy; Jaton, Pierre; Jawahery, Abolhassan; Jing, Fanfan; John, Malcolm; Johnson, Daniel; Jones, Christopher; Joram, Christian; Jost, Beat; Jurik, Nathan; Kaballo, Michael; Kandybei, Sergii; Kanso, Walaa; Karacson, Matthias; Karbach, Moritz; Karodia, Sarah; Kelsey, Matthew; Kenyon, Ian; Ketel, Tjeerd; Khanji, Basem; Khurewathanakul, Chitsanu; Klaver, Suzanne; Klimaszewski, Konrad; Kochebina, Olga; Kolpin, Michael; Komarov, Ilya; Koopman, Rose; Koppenburg, Patrick; Korolev, Mikhail; Kozlinskiy, Alexandr; Kravchuk, Leonid; Kreplin, Katharina; Kreps, Michal; Krocker, Georg; Krokovny, Pavel; Kruse, Florian; Kucewicz, Wojciech; Kucharczyk, Marcin; Kudryavtsev, Vasily; Kurek, Krzysztof; Kvaratskheliya, Tengiz; La Thi, Viet Nga; Lacarrere, Daniel; Lafferty, George; Lai, Adriano; Lambert, Dean; Lambert, Robert W; Lanfranchi, Gaia; Langenbruch, Christoph; Langhans, Benedikt; Latham, Thomas; Lazzeroni, Cristina; Le Gac, Renaud; van Leerdam, Jeroen; Lees, Jean-Pierre; Lefèvre, Regis; Leflat, Alexander; Lefrançois, Jacques; Leo, Sabato; Leroy, Olivier; Lesiak, Tadeusz; Leverington, Blake; Li, Yiming; Likhomanenko, Tatiana; Liles, Myfanwy; Lindner, Rolf; Linn, Christian; Lionetto, Federica; Liu, Bo; Lohn, Stefan; Longstaff, Iain; Lopes, Jose; Lopez-March, Neus; Lowdon, Peter; Lu, Haiting; Lucchesi, Donatella; Luo, Haofei; Lupato, Anna; Luppi, Eleonora; Lupton, Oliver; Machefert, Frederic; Machikhiliyan, Irina V; Maciuc, Florin; Maev, Oleg; Malde, Sneha; Malinin, Alexander; Manca, Giulia; Mancinelli, Giampiero; Mapelli, Alessandro; Maratas, Jan; Marchand, Jean François; Marconi, Umberto; Marin Benito, Carla; Marino, Pietro; Märki, Raphael; Marks, Jörg; Martellotti, Giuseppe; Martens, Aurelien; Martín Sánchez, Alexandra; Martinelli, Maurizio; Martinez Santos, Diego; Martinez Vidal, Fernando; Martins Tostes, Danielle; Massafferri, André; Matev, Rosen; Mathe, Zoltan; Matteuzzi, Clara; Mazurov, Alexander; McCann, Michael; McCarthy, James; McNab, Andrew; McNulty, Ronan; McSkelly, Ben; Meadows, Brian; Meier, Frank; Meissner, Marco; Merk, Marcel; Milanes, Diego Alejandro; Minard, Marie-Noelle; Moggi, Niccolò; Molina Rodriguez, Josue; Monteil, Stephane; Morandin, Mauro; Morawski, Piotr; Mordà, Alessandro; Morello, Michael Joseph; Moron, Jakub; Morris, Adam Benjamin; Mountain, Raymond; Muheim, Franz; Müller, Katharina; Mussini, Manuel; Muster, Bastien; Naik, Paras; Nakada, Tatsuya; Nandakumar, Raja; Nasteva, Irina; Needham, Matthew; Neri, Nicola; Neubert, Sebastian; Neufeld, Niko; Neuner, Max; Nguyen, Anh Duc; Nguyen, Thi-Dung; Nguyen-Mau, Chung; Nicol, Michelle; Niess, Valentin; Niet, Ramon; Nikitin, Nikolay; Nikodem, Thomas; Novoselov, Alexey; O'Hanlon, Daniel Patrick; Oblakowska-Mucha, Agnieszka; Obraztsov, Vladimir; Oggero, Serena; Ogilvy, Stephen; Okhrimenko, Oleksandr; Oldeman, Rudolf; Onderwater, Gerco; Orlandea, Marius; Otalora Goicochea, Juan Martin; Owen, Patrick; Oyanguren, Maria Arantza; Pal, Bilas Kanti; Palano, Antimo; Palombo, Fernando; Palutan, Matteo; Panman, Jacob; Papanestis, Antonios; Pappagallo, Marco; Pappalardo, Luciano; Parkes, Christopher; Parkinson, Christopher John; Passaleva, Giovanni; Patel, Girish; Patel, Mitesh; Patrignani, Claudia; Pazos Alvarez, Antonio; Pearce, Alex; Pellegrino, Antonio; Pepe Altarelli, Monica; Perazzini, Stefano; Perez Trigo, Eliseo; Perret, Pascal; Perrin-Terrin, Mathieu; Pescatore, Luca; Pesen, Erhan; Petridis, Konstantin; Petrolini, Alessandro; Picatoste Olloqui, Eduardo; Pietrzyk, Boleslaw; Pilař, Tomas; Pinci, Davide; Pistone, Alessandro; Playfer, Stephen; Plo Casasus, Maximo; Polci, Francesco; Poluektov, Anton; Polycarpo, Erica; Popov, Alexander; Popov, Dmitry; Popovici, Bogdan; Potterat, Cédric; Price, Eugenia; Price, Joseph David; Prisciandaro, Jessica; Pritchard, Adrian; Prouve, Claire; Pugatch, Valery; Puig Navarro, Albert; Punzi, Giovanni; Qian, Wenbin; Rachwal, Bartolomiej; Rademacker, Jonas; Rakotomiaramanana, Barinjaka; Rama, Matteo; Rangel, Murilo; Raniuk, Iurii; Rauschmayr, Nathalie; Raven, Gerhard; Redi, Federico; Reichert, Stefanie; Reid, Matthew; dos Reis, Alberto; Ricciardi, Stefania; Richards, Sophie; Rihl, Mariana; Rinnert, Kurt; Rives Molina, Vincente; Robbe, Patrick; Rodrigues, Ana Barbara; Rodrigues, Eduardo; Rodriguez Perez, Pablo; Roiser, Stefan; Romanovsky, Vladimir; Romero Vidal, Antonio; Rotondo, Marcello; Rouvinet, Julien; Ruf, Thomas; Ruiz, Hugo; Ruiz Valls, Pablo; Saborido Silva, Juan Jose; Sagidova, Naylya; Sail, Paul; Saitta, Biagio; Salustino Guimaraes, Valdir; Sanchez Mayordomo, Carlos; Sanmartin Sedes, Brais; Santacesaria, Roberta; Santamarina Rios, Cibran; Santovetti, Emanuele; Sarti, Alessio; Satriano, Celestina; Satta, Alessia; Saunders, Daniel Martin; Savrie, Mauro; Savrina, Darya; Schiller, Manuel; Schindler, Heinrich; Schlupp, Maximilian; Schmelling, Michael; Schmidt, Burkhard; Schneider, Olivier; Schopper, Andreas; Schune, Marie Helene; Schwemmer, Rainer; Sciascia, Barbara; Sciubba, Adalberto; Seco, Marcos; Semennikov, Alexander; Sepp, Indrek; Serra, Nicola; Serrano, Justine; Sestini, Lorenzo; Seyfert, Paul; Shapkin, Mikhail; Shapoval, Illya; Shcheglov, Yury; Shears, Tara; Shekhtman, Lev; Shevchenko, Vladimir; Shires, Alexander; Silva Coutinho, Rafael; Simi, Gabriele; Sirendi, Marek; Skidmore, Nicola; Skwarnicki, Tomasz; Smith, Anthony; Smith, Edmund; Smith, Eluned; Smith, Jackson; Smith, Mark; Snoek, Hella; Sokoloff, Michael; Soler, Paul; Soomro, Fatima; Souza, Daniel; Souza De Paula, Bruno; Spaan, Bernhard; Sparkes, Ailsa; Spradlin, Patrick; Sridharan, Srikanth; Stagni, Federico; Stahl, Marian; Stahl, Sascha; Steinkamp, Olaf; Stenyakin, Oleg; Stevenson, Scott; Stoica, Sabin; Stone, Sheldon; Storaci, Barbara; Stracka, Simone; Straticiuc, Mihai; Straumann, Ulrich; Stroili, Roberto; Subbiah, Vijay Kartik; Sun, Liang; Sutcliffe, William; Swientek, Krzysztof; Swientek, Stefan; Syropoulos, Vasileios; Szczekowski, Marek; Szczypka, Paul; Szilard, Daniela; Szumlak, Tomasz; T'Jampens, Stephane; Teklishyn, Maksym; Tellarini, Giulia; Teubert, Frederic; Thomas, Christopher; Thomas, Eric; van Tilburg, Jeroen; Tisserand, Vincent; Tobin, Mark; Tolk, Siim; Tomassetti, Luca; Topp-Joergensen, Stig; Torr, Nicholas; Tournefier, Edwige; Tourneur, Stephane; Tran, Minh Tâm; Tresch, Marco; Tsaregorodtsev, Andrei; Tsopelas, Panagiotis; Tuning, Niels; Ubeda Garcia, Mario; Ukleja, Artur; Ustyuzhanin, Andrey; Uwer, Ulrich; Vacca, Claudia; Vagnoni, Vincenzo; Valenti, Giovanni; Vallier, Alexis; Vazquez Gomez, Ricardo; Vazquez Regueiro, Pablo; Vázquez Sierra, Carlos; Vecchi, Stefania; Velthuis, Jaap; Veltri, Michele; Veneziano, Giovanni; Vesterinen, Mika; Viaud, Benoit; Vieira, Daniel; Vieites Diaz, Maria; Vilasis-Cardona, Xavier; Vollhardt, Achim; Volyanskyy, Dmytro; Voong, David; Vorobyev, Alexey; Vorobyev, Vitaly; Voß, Christian; Voss, Helge; de Vries, Jacco; Waldi, Roland; Wallace, Charlotte; Wallace, Ronan; Walsh, John; Wandernoth, Sebastian; Wang, Jianchun; Ward, David; Watson, Nigel; Websdale, David; Whitehead, Mark; Wicht, Jean; Wiedner, Dirk; Wilkinson, Guy; Williams, Matthew; Williams, Mike; Wilschut, Hans; Wilson, Fergus; Wimberley, Jack; Wishahi, Julian; Wislicki, Wojciech; Witek, Mariusz; Wormser, Guy; Wotton, Stephen; Wright, Simon; Wyllie, Kenneth; Xie, Yuehong; Xing, Zhou; Xu, Zhirui; Yang, Zhenwei; Yuan, Xuhao; Yushchenko, Oleg; Zangoli, Maria; Zavertyaev, Mikhail; Zhang, Liming; Zhang, Wen Chao; Zhang, Yanxi; Zhelezov, Alexey; Zhokhov, Anatoly; Zhong, Liang; Zvyagin, Alexander

2015-01-01

Using the latest LHCb measurements of time-dependent $C\\!P$ violation in the $B^0_s \\to K^+K^-$ decay, a U-spin relation between the decay amplitudes of $B^0_s \\to K^+K^-$ and $B^0\\to \\pi^+\\pi^-$ decay processes allows constraints to be placed on the angle $\\gamma$ of the unitarity triangle and on the $B^0_s$ mixing phase $-2\\beta_s$. Results from an extended approach, which uses additional inputs on $B^0\\to \\pi^0\\pi^0$ and $B^+\\to \\pi^+\\pi^0$ decays from other experiments and exploits isospin symmetry, are also presented. The dependence of the results on the maximum allowed amount of U-spin breaking is studied. At 68% probability, the value $\\gamma = \\left( 63.5^{\\,+\\, 7.2}_{\\,-\\,6.7} \\right)^\\circ~\\mathrm{modulo}~180^\\circ$ is determined. In an alternative analysis, the value $-2\\beta_s = -0.12 ^{\\,+\\,0.14}_{\\,-\\,0.16}\\,\\,\\mathrm{rad}$ is found. In both measurements, the uncertainties due to U-spin breaking effects up to 50% are included.

Determination of $\\gamma$ and $-2\\beta_s$ from charmless two-body decays of beauty mesons

CERN Document Server

Aaij, Roel; Adeva, Bernardo; Adinolfi, Marco; Affolder, Anthony; Ajaltouni, Ziad; Akar, Simon; Albrecht, Johannes; Alessio, Federico; Alexander, Michael; Ali, Suvayu; Alkhazov, Georgy; Alvarez Cartelle, Paula; Alves Jr, Antonio Augusto; Amato, Sandra; Amerio, Silvia; Amhis, Yasmine; An, Liupan; Anderlini, Lucio; Anderson, Jonathan; Andreassen, Rolf; Andreotti, Mirco; Andrews, Jason; Appleby, Robert; Aquines Gutierrez, Osvaldo; Archilli, Flavio; Artamonov, Alexander; Artuso, Marina; Aslanides, Elie; Auriemma, Giulio; Baalouch, Marouen; Bachmann, Sebastian; Back, John; Badalov, Alexey; Baesso, Clarissa; Baldini, Wander; Barlow, Roger; Barschel, Colin; Barsuk, Sergey; Barter, William; Batozskaya, Varvara; Battista, Vincenzo; Bay, Aurelio; Beaucourt, Leo; Beddow, John; Bedeschi, Franco; Bediaga, Ignacio; Belogurov, Sergey; Belous, Konstantin; Belyaev, Ivan; Ben-Haim, Eli; Bencivenni, Giovanni; Benson, Sean; Benton, Jack; Berezhnoy, Alexander; Bernet, Roland; Bettler, Marc-Olivier; van Beuzekom, Martinus; Bien, Alexander; Bifani, Simone; Bird, Thomas; Bizzeti, Andrea; Bjørnstad, Pål Marius; Blake, Thomas; Blanc, Frédéric; Blouw, Johan; Blusk, Steven; Bocci, Valerio; Bondar, Alexander; Bondar, Nikolay; Bonivento, Walter; Borghi, Silvia; Borgia, Alessandra; Borsato, Martino; Bowcock, Themistocles; Bowen, Espen Eie; Bozzi, Concezio; Brambach, Tobias; Bressieux, Joël; Brett, David; Britsch, Markward; Britton, Thomas; Brodzicka, Jolanta; Brook, Nicholas; Brown, Henry; Bursche, Albert; Busetto, Giovanni; Buytaert, Jan; Cadeddu, Sandro; Calabrese, Roberto; Calvi, Marta; Calvo Gomez, Miriam; Campana, Pierluigi; Campora Perez, Daniel; Carbone, Angelo; Carboni, Giovanni; Cardinale, Roberta; Cardini, Alessandro; Carson, Laurence; Carvalho Akiba, Kazuyoshi; Casse, Gianluigi; Cassina, Lorenzo; Castillo Garcia, Lucia; Cattaneo, Marco; Cauet, Christophe; Cenci, Riccardo; Charles, Matthew; Charpentier, Philippe; Chefdeville, Maximilien; Chen, Shanzhen; Cheung, Shu-Faye; Chiapolini, Nicola; Chrzaszcz, Marcin; Ciba, Krzystof; Cid Vidal, Xabier; Ciezarek, Gregory; Clarke, Peter; Clemencic, Marco; Cliff, Harry; Closier, Joel; Coco, Victor; Cogan, Julien; Cogneras, Eric; Cojocariu, Lucian; Collins, Paula; Comerma-Montells, Albert; Contu, Andrea; Cook, Andrew; Coombes, Matthew; Coquereau, Samuel; Corti, Gloria; Corvo, Marco; Counts, Ian; Couturier, Benjamin; Cowan, Greig; Craik, Daniel Charles; Cruz Torres, Melissa Maria; Cunliffe, Samuel; Currie, Robert; D'Ambrosio, Carmelo; Dalseno, Jeremy; David, Pascal; David, Pieter; Davis, Adam; De Bruyn, Kristof; De Capua, Stefano; De Cian, Michel; De Miranda, Jussara; De Paula, Leandro; De Silva, Weeraddana; De Simone, Patrizia; Decamp, Daniel; Deckenhoff, Mirko; Del Buono, Luigi; Déléage, Nicolas; Derkach, Denis; Deschamps, Olivier; Dettori, Francesco; Di Canto, Angelo; Dijkstra, Hans; Donleavy, Stephanie; Dordei, Francesca; Dorigo, Mirco; Dosil Suárez, Alvaro; Dossett, David; Dovbnya, Anatoliy; Dreimanis, Karlis; Dujany, Giulio; Dupertuis, Frederic; Durante, Paolo; Dzhelyadin, Rustem; Dziurda, Agnieszka; Dzyuba, Alexey; Easo, Sajan; Egorychev, Victor; Eidelman, Semen; Eisenhardt, Stephan; Eitschberger, Ulrich; Ekelhof, Robert; Eklund, Lars; El Rifai, Ibrahim; Elsasser, Christian; Ely, Scott; Esen, Sevda; Evans, Hannah Mary; Evans, Timothy; Falabella, Antonio; Färber, Christian; Farinelli, Chiara; Farley, Nathanael; Farry, Stephen; Fay, Robert; Ferguson, Dianne; Fernandez Albor, Victor; Ferreira Rodrigues, Fernando; Ferro-Luzzi, Massimiliano; Filippov, Sergey; Fiore, Marco; Fiorini, Massimiliano; Firlej, Miroslaw; Fitzpatrick, Conor; Fiutowski, Tomasz; Fol, Philip; Fontana, Marianna; Fontanelli, Flavio; Forty, Roger; Francisco, Oscar; Frank, Markus; Frei, Christoph; Frosini, Maddalena; Fu, Jinlin; Furfaro, Emiliano; Gallas Torreira, Abraham; Galli, Domenico; Gallorini, Stefano; Gambetta, Silvia; Gandelman, Miriam; Gandini, Paolo; Gao, Yuanning; García Pardiñas, Julián; Garofoli, Justin; Garra Tico, Jordi; Garrido, Lluis; Gaspar, Clara; Gauld, Rhorry; Gavardi, Laura; Gavrilov, Gennadii; Geraci, Angelo; Gersabeck, Evelina; Gersabeck, Marco; Gershon, Timothy; Ghez, Philippe; Gianelle, Alessio; Gianì, Sebastiana; Gibson, Valerie; Giubega, Lavinia-Helena; Gligorov, V.V.; Göbel, Carla; Golubkov, Dmitry; Golutvin, Andrey; Gomes, Alvaro; Gotti, Claudio; Grabalosa Gándara, Marc; Graciani Diaz, Ricardo; Granado Cardoso, Luis Alberto; Graugés, Eugeni; Graziani, Giacomo; Grecu, Alexandru; Greening, Edward; Gregson, Sam; Griffith, Peter; Grillo, Lucia; Grünberg, Oliver; Gui, Bin; Gushchin, Evgeny; Guz, Yury; Gys, Thierry; Hadjivasiliou, Christos; Haefeli, Guido; Haen, Christophe; Haines, Susan; Hall, Samuel; Hamilton, Brian; Hampson, Thomas; Han, Xiaoxue; Hansmann-Menzemer, Stephanie; Harnew, Neville; Harnew, Samuel; Harrison, Jonathan; He, Jibo; Head, Timothy; Heijne, Veerle; Hennessy, Karol; Henrard, Pierre; Henry, Louis; Hernando Morata, Jose Angel; van Herwijnen, Eric; Heß, Miriam; Hicheur, Adlène; Hill, Donal; Hoballah, Mostafa; Hombach, Christoph; Hulsbergen, Wouter; Hunt, Philip; Hussain, Nazim; Hutchcroft, David; Hynds, Daniel; Idzik, Marek; Ilten, Philip; Jacobsson, Richard; Jaeger, Andreas; Jalocha, Pawel; Jans, Eddy; Jaton, Pierre; Jawahery, Abolhassan; Jing, Fanfan; John, Malcolm; Johnson, Daniel; Jones, Christopher; Joram, Christian; Jost, Beat; Jurik, Nathan; Kaballo, Michael; Kandybei, Sergii; Kanso, Walaa; Karacson, Matthias; Karbach, Moritz; Karodia, Sarah; Kelsey, Matthew; Kenyon, Ian; Ketel, Tjeerd; Khanji, Basem; Khurewathanakul, Chitsanu; Klaver, Suzanne; Klimaszewski, Konrad; Kochebina, Olga; Kolpin, Michael; Komarov, Ilya; Koopman, Rose; Koppenburg, Patrick; Korolev, Mikhail; Kozlinskiy, Alexandr; Kravchuk, Leonid; Kreplin, Katharina; Kreps, Michal; Krocker, Georg; Krokovny, Pavel; Kruse, Florian; Kucewicz, Wojciech; Kucharczyk, Marcin; Kudryavtsev, Vasily; Kurek, Krzysztof; Kvaratskheliya, Tengiz; La Thi, Viet Nga; Lacarrere, Daniel; Lafferty, George; Lai, Adriano; Lambert, Dean; Lambert, Robert W; Lanfranchi, Gaia; Langenbruch, Christoph; Langhans, Benedikt; Latham, Thomas; Lazzeroni, Cristina; Le Gac, Renaud; van Leerdam, Jeroen; Lees, Jean-Pierre; Lefèvre, Regis; Leflat, Alexander; Lefrançois, Jacques; Leo, Sabato; Leroy, Olivier; Lesiak, Tadeusz; Leverington, Blake; Li, Yiming; Likhomanenko, Tatiana; Liles, Myfanwy; Lindner, Rolf; Linn, Christian; Lionetto, Federica; Liu, Bo; Lohn, Stefan; Longstaff, Iain; Lopes, Jose; Lopez-March, Neus; Lowdon, Peter; Lu, Haiting; Lucchesi, Donatella; Luo, Haofei; Lupato, Anna; Luppi, Eleonora; Lupton, Oliver; Machefert, Frederic; Machikhiliyan, Irina V; Maciuc, Florin; Maev, Oleg; Malde, Sneha; Malinin, Alexander; Manca, Giulia; Mancinelli, Giampiero; Mapelli, Alessandro; Maratas, Jan; Marchand, Jean François; Marconi, Umberto; Marin Benito, Carla; Marino, Pietro; Märki, Raphael; Marks, Jörg; Martellotti, Giuseppe; Martens, Aurelien; Martín Sánchez, Alexandra; Martinelli, Maurizio; Martinez Santos, Diego; Martinez Vidal, Fernando; Martins Tostes, Danielle; Massafferri, André; Matev, Rosen; Mathe, Zoltan; Matteuzzi, Clara; Mazurov, Alexander; McCann, Michael; McCarthy, James; McNab, Andrew; McNulty, Ronan; McSkelly, Ben; Meadows, Brian; Meier, Frank; Meissner, Marco; Merk, Marcel; Milanes, Diego Alejandro; Minard, Marie-Noelle; Moggi, Niccolò; Molina Rodriguez, Josue; Monteil, Stephane; Morandin, Mauro; Morawski, Piotr; Mordà, Alessandro; Morello, Michael Joseph; Moron, Jakub; Morris, Adam Benjamin; Mountain, Raymond; Muheim, Franz; Müller, Katharina; Mussini, Manuel; Muster, Bastien; Naik, Paras; Nakada, Tatsuya; Nandakumar, Raja; Nasteva, Irina; Needham, Matthew; Neri, Nicola; Neubert, Sebastian; Neufeld, Niko; Neuner, Max; Nguyen, Anh Duc; Nguyen, Thi-Dung; Nguyen-Mau, Chung; Nicol, Michelle; Niess, Valentin; Niet, Ramon; Nikitin, Nikolay; Nikodem, Thomas; Novoselov, Alexey; O'Hanlon, Daniel Patrick; Oblakowska-Mucha, Agnieszka; Obraztsov, Vladimir; Oggero, Serena; Ogilvy, Stephen; Okhrimenko, Oleksandr; Oldeman, Rudolf; Onderwater, Gerco; Orlandea, Marius; Otalora Goicochea, Juan Martin; Owen, Patrick; Oyanguren, Maria Arantza; Pal, Bilas Kanti; Palano, Antimo; Palombo, Fernando; Palutan, Matteo; Panman, Jacob; Papanestis, Antonios; Pappagallo, Marco; Pappalardo, Luciano; Parkes, Christopher; Parkinson, Christopher John; Passaleva, Giovanni; Patel, Girish; Patel, Mitesh; Patrignani, Claudia; Pazos Alvarez, Antonio; Pearce, Alex; Pellegrino, Antonio; Pepe Altarelli, Monica; Perazzini, Stefano; Perez Trigo, Eliseo; Perret, Pascal; Perrin-Terrin, Mathieu; Pescatore, Luca; Pesen, Erhan; Petridis, Konstantin; Petrolini, Alessandro; Picatoste Olloqui, Eduardo; Pietrzyk, Boleslaw; Pilař, Tomas; Pinci, Davide; Pistone, Alessandro; Playfer, Stephen; Plo Casasus, Maximo; Polci, Francesco; Poluektov, Anton; Polycarpo, Erica; Popov, Alexander; Popov, Dmitry; Popovici, Bogdan; Potterat, Cédric; Price, Eugenia; Price, Joseph David; Prisciandaro, Jessica; Pritchard, Adrian; Prouve, Claire; Pugatch, Valery; Puig Navarro, Albert; Punzi, Giovanni; Qian, Wenbin; 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Schune, Marie Helene; Schwemmer, Rainer; Sciascia, Barbara; Sciubba, Adalberto; Seco, Marcos; Semennikov, Alexander; Sepp, Indrek; Serra, Nicola; Serrano, Justine; Sestini, Lorenzo; Seyfert, Paul; Shapkin, Mikhail; Shapoval, Illya; Shcheglov, Yury; Shears, Tara; Shekhtman, Lev; Shevchenko, Vladimir; Shires, Alexander; Silva Coutinho, Rafael; Simi, Gabriele; Sirendi, Marek; Skidmore, Nicola; Skwarnicki, Tomasz; Smith, Anthony; Smith, Edmund; Smith, Eluned; Smith, Jackson; Smith, Mark; Snoek, Hella; Sokoloff, Michael; Soler, Paul; Soomro, Fatima; Souza, Daniel; Souza De Paula, Bruno; Spaan, Bernhard; Sparkes, Ailsa; Spradlin, Patrick; Sridharan, Srikanth; Stagni, Federico; Stahl, Marian; Stahl, Sascha; Steinkamp, Olaf; Stenyakin, Oleg; Stevenson, Scott; Stoica, Sabin; Stone, Sheldon; Storaci, Barbara; Stracka, Simone; Straticiuc, Mihai; Straumann, Ulrich; Stroili, Roberto; Subbiah, Vijay Kartik; Sun, Liang; Sutcliffe, William; Swientek, Krzysztof; Swientek, Stefan; Syropoulos, Vasileios; 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Walsh, John; Wandernoth, Sebastian; Wang, Jianchun; Ward, David; Watson, Nigel; Websdale, David; Whitehead, Mark; Wicht, Jean; Wiedner, Dirk; Wilkinson, Guy; Williams, Matthew; Williams, Mike; Wilschut, Hans; Wilson, Fergus; Wimberley, Jack; Wishahi, Julian; Wislicki, Wojciech; Witek, Mariusz; Wormser, Guy; Wotton, Stephen; Wright, Simon; Wyllie, Kenneth; Xie, Yuehong; Xing, Zhou; Xu, Zhirui; Yang, Zhenwei; Yuan, Xuhao; Yushchenko, Oleg; Zangoli, Maria; Zavertyaev, Mikhail; Zhang, Liming; Zhang, Wen Chao; Zhang, Yanxi; Zhelezov, Alexey; Zhokhov, Anatoly; Zhong, Liang; Zvyagin, Alexander

2015-02-04

Using the latest LHCb measurements of time-dependent $C\\!P$ violation in the $B^0_s \\to K^+K^-$ decay, a U-spin relation between the decay amplitudes of $B^0_s \\to K^+K^-$ and $B^0\\to \\pi^+\\pi^-$ decay processes allows constraints to be placed on the angle $\\gamma$ of the unitarity triangle and on the $B^0_s$ mixing phase $-2\\beta_s$. Results from an extended approach, which uses additional inputs on $B^0\\to \\pi^0\\pi^0$ and $B^+\\to \\pi^+\\pi^0$ decays from other experiments and exploits isospin symmetry, are also presented. The dependence of the results on the maximum allowed amount of U-spin breaking is studied. At 68% probability, the value $\\gamma = \\left( 63.5^{\\,+\\, 7.2}_{\\,-\\,6.7} \\right)^\\circ~\\mathrm{modulo}~180^\\circ$ is determined. In an alternative analysis, the value $-2\\beta_s = -0.12 ^{\\,+\\,0.14}_{\\,-\\,0.16}\\,\\,\\mathrm{rad}$ is found. In both measurements, the uncertainties due to U-spin breaking effects up to 50% are included.

Sigma beta decay

International Nuclear Information System (INIS)

Newman, D.E.

1975-01-01

Describes an experiment to measure beta decays of the sigma particle. Sigmas produced by stopping a K - beam in a liquid hydrogen target decayed in the following reactions: Kp → Σπ; Σ → Neν. The electron and pion were detected by wire spark chambers in a magnetic spectrometer and by plastic scintillators, and were differentiated by a threshold gas Cherenkov counter. The neutron was detected by liquid scintillation counters. The data (n = 3) shell electrons or the highly excited electrons decay first. Instead, it is suggested that when there are two to five electrons in highly excited states immediately after a heavy ion--atom collision the first transitions to occur will be among highly excited Rydberg states in a cascade down to the 4s, 4p, and 3d-subshells. If one of the long lived states becomes occupied by electrons promoted during the collision or by electrons falling from higher levels, it will not decay until after the valence shell decays. LMM rates calculated to test the methods used are compared to previous works. The mixing coefficients are given in terms of the states 4s4p, 45sp+-, and 5s5p. The applicability of Cooper, Fano, and Prats' discussion of the energies and transition rates of doubly excited states is considered

Beta decay of 72Co and excited levels in 72Ni

International Nuclear Information System (INIS)

Grzywacz, R.; Rykaczewski, K.; Sawicka, M.; Pfuetzner, M.; Daugas, J.M.; Belier, G.; Sauvestre, J.E.; Meot, V.; Roig, O.; Giovinazzo, J.; Grawe, H.; Mayet, P.; Matea, I.; Georgiev, G.; Lewitowicz, M.; Olivieira, F. de; Stodel, C.; Saint-Laurent, M. G.; Stanoiu, M.; Verney, D.

2003-01-01

An experiment was performed at GANIL to observe isomeric- and beta-delayed gamma rays from very neutron-rich nuclei around 74Ni. Fragmentation products of the 86Kr beam at 58 AMeV were studied using new devices: the LISE 2000 spectrometer and detectors from the EXOGAM germanium array. The primary aim of the experiment was to find the 8+ microsecond isomer in 76Ni and to perform beta decay spectroscopy of Co nuclei. We have successfully measured the beta delayed gammas from the decay of 72Co to 72Ni. The energies for the lowest excited states in 72Ni are proposed, with the first 2+ state at 1096 keV. These findings suggest a solution of the problem of the disappearance of the 8+ isomer in 72Ni. We also measured beta decay of other neutron-rich Co isotopes including 70Co. First evidence was found for a new short lived isomer, most likely the Iπ=8+ state, in 76Ni

Searches for double beta decay of {}^{134}\mathrm{Xe} with EXO-200

Energy Technology Data Exchange (ETDEWEB)

Albert, J. B.; Anton, G.; Badhrees, I.; Barbeau, P. S.; Bayerlein, R.; Beck, D.; Belov, V.; Breidenbach, M.; Brunner, T.; Cao, G. F.; Cen, W. R.; Chambers, C.; Cleveland, B.; Coon, M.; Craycraft, A.; Cree, W.; Daniels, T.; Danilov, M.; Daugherty, S. J.; Daughhetee, J.; Davis, J.; Delaquis, S.; Der Mesrobian-Kabakian, A.; DeVoe, R.; Didberidze, T.; Dilling, J.; Dolgolenko, A.; Dolinski, M. J.; Fairbank, W.; Farine, J.; Feyzbakhsh, S.; Fierlinger, P.; Fudenberg, D.; Gornea, R.; Graham, K.; Gratta, G.; Hall, C.; Hoessl, J.; Hufschmidt, P.; Hughes, M.; Jamil, A.; Jewell, M. J.; Johnson, A.; Johnston, S.; Karelin, A.; Kaufman, L. J.; Koffas, T.; Kravitz, S.; Krücken, R.; Kuchenkov, A.; Kumar, K. S.; Lan, Y.; Leonard, D. S.; Li, S.; Licciardi, C.; Lin, Y. H.; MacLellan, R.; Marino, M. G.; Michel, T.; Mong, B.; Moore, D.; Murray, K.; Nelson, R.; Njoya, O.; Odian, A.; Ostrovskiy, I.; Piepke, A.; Pocar, A.; Retière, F.; Rowson, P. C.; Russell, J. J.; Schubert, A.; Sinclair, D.; Smith, E.; Stekhanov, V.; Tarka, M.; Tolba, T.; Tsang, R.; Vogel, P.; Vuilleumier, J. -L.; Wagenpfeil, M.; Waite, A.; Walton, J.; Walton, T.; Weber, M.; Wen, L. J.; Wichoski, U.; Yang, L.; Yen, Y. -R.; Zeldovich, O. Ya.; Zettlemoyer, J.; Ziegler, T.

2017-11-01

Searches for double beta decay of 134Xe were performed with EXO-200, a single-phase liquid xenon detector designed to search for neutrinoless double beta decay of 136Xe. Using an exposure of 29.6 kg · yr, the lower limits of T2νββ 1=2 > 8.7 × 1020 yr and T0νββ 1=2 > 1.1 × 1023 yr at 90% confidence level were derived, with corresponding half-life sensitivities of 1.2 × 1021 yr and 1.9 × 1023 yr. These limits exceed those in the literature for 134Xe, improving by factors of nearly 105 and 2 for the two antineutrino and neutrinoless modes, respectively.

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

Directory of Open Access Journals (Sweden)

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.

An investigation of proton pair correlations relevant to the neutrinoless double beta decay of 76Ge

Science.gov (United States)

Ticehurst, David R.

The observation of neutrinoless double beta decay (0nubetabeta ) would demonstrate that the neutrino is a Majorana particle and allow determination of its mass by comparing the measured decay rate to the calculated rate. The main uncertainty in the calculation of the 0 nubetabeta rate is due to uncertainties in the nuclear structure models used in the computation of the nuclear matrix elements for the decay process. This project tested the validity of using wavefunctions for the nuclear states involved in the 0nubetabeta process that are based on a first-order application of the Bardeen-Cooper-Schrieffer (BCS) theory of superconductivity. In the BCS approximation, most of the strength for two-nucleon transfer reactions should be for transitions to the 0 + ground state of the final nucleus (i.e., little strength should go to the 0+ excited states). This experiment measured the strength to the first 0+ excited state for the 74Ge( 3He,n)76Se and 76Ge( 3He,n)78Se reactions relative to the strength for transition to the 0+ ground state in selenium. For both nuclei, and at 3He beam energies of 15 and 21 MeV, the observed relative strength for transfer to the first 0+ excited state was less than 13%. This result supports the validity of using the BCS approximation to describe the ground state of both 76Se and 78Se and is consistent with the results of recent ( 3He,n) cross section measurements on 74Ge and 76Ge. In addition, the magnitude and shape of the measured angular distributions suggest that contribution of the sequential two-nucleon transfer process, which is an indicator of long-range nucleon-nucleon correlations, is over-predicted by the DWBA code FRESCO.

Induced nuclear beta decay

International Nuclear Information System (INIS)

Reiss, H.R.

1986-01-01

Certain nuclear beta decay transitions normally inhibited by angular momentum or parity considerations can be induced to occur by the application of an electromagnetic field. Such decays can be useful in the controlled production of power, and in fission waste disposal

GERDA, a GERmanium Detector Array for the search for neutrinoless ββ decay in 76Ge

International Nuclear Information System (INIS)

Pandola, L.; Tomei, C.

2006-01-01

The GERDA project, searching for neutrinoless double beta-decay of 76Ge with enriched germanium detectors submerged in a cryogenic bath, has been approved for installation at the Gran Sasso National Laboratory (LNGS), Italy. The GERDA technique is aiming at a dramatic reduction of the background due to radioactive contaminations of the materials surrounding the detectors. This will lead to a sensitivity of about 1026 years on the half-life of neutrinoless double beta decay. Already in the first phase of the experiment, GERDA will be able to investigate with high statistical significance the claimed evidence for neutrinoless double beta decay of 76Ge based on the data of the Heidelberg-Moscow experiment

Measurement of the two neutrino double beta decay half-life of Zr-96 with the NEMO-3 detector

Energy Technology Data Exchange (ETDEWEB)

Argyriades, J. [LAL, Universite Paris-Sud 11, CNRS/IN2P3, F-91405 Orsay (France); Arnold, R. [IPHC, Universite de Strasbourg, CNRS/IN2P3, F-67037 Strasbourg (France); Augier, C. [LAL, Universite Paris-Sud 11, CNRS/IN2P3, F-91405 Orsay (France); Baker, J. [INL, Idaho National Laboratory, 83415 Idaho Falls (United States); Barabash, A.S. [ITEP, Institute of Theoretical and Experimental Physics, 117259 Moscow (Russian Federation); Basharina-Freshville, A. [University College London, WC1E 6BT London (United Kingdom); Bongrand, M. [LAL, Universite Paris-Sud 11, CNRS/IN2P3, F-91405 Orsay (France); Broudin-Bay, G. [Universite Bordeaux, CENBG, UMR 5797, F-33175 Gradignan (France); CNRS/IN2P3, Centre d' Etudes Nucleaires de Bordeaux Gradignan, UMR5797, F-33175 Gradignan (France); Brudanin, V. [JINR, Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Caffrey, A.J. [INL, Idaho National Laboratory, 83415 Idaho Falls (United States); Chapon, A. [LPC, ENSICAEN, Universite de Caen, CNRS/IN2P3, F-14032 Caen (France); Chauveau, E. [Universite Bordeaux, CENBG, UMR 5797, F-33175 Gradignan (France); CNRS/IN2P3, Centre d' Etudes Nucleaires de Bordeaux Gradignan, UMR5797, F-33175 Gradignan (France); Daraktchieva, Z. [University College London, WC1E 6BT London (United Kingdom); Durand, D. [LPC, ENSICAEN, Universite de Caen, CNRS/IN2P3, F-14032 Caen (France); Egorov, V. [JINR, Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Fatemi-Ghomi, N. [University of Manchester, M13 9PL Manchester (United Kingdom); Flack, R. [University College London, WC1E 6BT London (United Kingdom); Guillon, B. [LPC, ENSICAEN, Universite de Caen, CNRS/IN2P3, F-14032 Caen (France); Hubert, Ph. [Universite Bordeaux, CENBG, UMR 5797, F-33175 Gradignan (France); CNRS/IN2P3, Centre d' Etudes Nucleaires de Bordeaux Gradignan, UMR5797, F-33175 Gradignan (France); Jullian, S. [LAL, Universite Paris-Sud 11, CNRS/IN2P3, F-91405 Orsay (France)

2010-12-08

Using 9.4 g of {sup 96}Zr isotope and 1221 days of data from the NEMO-3 detector corresponding to 0.031 kg y, the obtained 2{nu}{beta}{beta} decay half-life measurement is T{sub 1/2}{sup 2{nu}=}[2.35{+-}0.14(stat){+-}0.16(syst)]x10{sup 19} yr. Different characteristics of the final state electrons have been studied, such as the energy sum, individual electron energy, and angular distribution. The 2{nu} nuclear matrix element is extracted using the measured 2{nu}{beta}{beta} half-life and is M{sup 2{nu}=}0.049{+-}0.002. Constraints on 0{nu}{beta}{beta} decay have also been set.

Beta-decay and decay heat. Summary report of consultants' meeting

International Nuclear Information System (INIS)

Nicols, A.L.

2006-01-01

Experts on decay data and decay heat calculations participated in a Consultants' Meeting organized at IAEA Headquarters on 12-14 December 2005. Debate focused on the validation of decay heat calculations as a function of cooling time for fuel irradiated in power reactors through comparisons with experimental benchmark data. Both the current understanding and quantification of mean beta and gamma decay energies were reviewed with respect to measurements and the Gross Theory of Beta Decay. Particular emphasis was placed on the known development of total absorption gamma-ray spectroscopy (TAGS), and detailed discussions took place to formulate the measurement requirements for mean beta and gamma data of individual radionuclides. This meeting was organized in cooperation with the OECD/NEA Working Party for Evaluation and Cooperation (WPEC). Proposals and recommendations were made to resolve particular difficulties, and an initial list of fission products was produced for TAGS studies. The discussions, conclusions and recommendations of the meeting are briefly described in this report. (author)

Measuring pion beta decay with high-energy pion beams

International Nuclear Information System (INIS)

McFarlane, W.K.; Hoffman, C.M.

1993-01-01

Improved measurements of the pion beta decay rate are possible with an intense high-energy pion beam. The rate for the decay π + → π 0 e + vε is predicted by the Standard Model (SM) to be R(π + → π 0 e + vε) = 0.3999±0.0005 s -1 . The best experimental number, obtained using in-flight decays, is R(π + → π 0 e + vε) = 0.394 ± 0.015 s -1 . A precise measurement would test the SM by testing the unitarity of the Cabibbo-Kobayashi-Maskawa matrix for which one analysis of the nuclear beta decay data has shown a 0.4% discrepancy. Several nuclear correction factors, needed for nuclear decay, are not present for pion beta decay, so that an experiment at the 0.2% level would be a significant one. Detailed study of possible designs will be needed, as well as extensive testing of components. The reduction of systematic errors to the 0.1% level can only be done over a period of years with a highly stable apparatus and beam. At a minimum, three years of occupancy of a beam line, with 800 hours per year, would be required

Gamow-Teller beta decay of proton-rich nuclei

International Nuclear Information System (INIS)

Klepper, O.; Rykaczewski, K.

1990-11-01

The beta decays of 48 Mn and of even-even nuclei near the double shell-closures at 100 Sn and 146 Gd are currently investigated at the GSI on-line mass separator. Their Gamow-Teller strength are surveyed in their present experimental status, together with related results from the ISOLDE (CERN) and ISOCELE (Orsay) separators, and are compared with predictions from different nuclear models. The strength of the 0 + → 1 + Gamow-Teller transitions is compiled in tables and graphs. (orig.)

Isotensor Axial Polarizability and Lattice QCD Input for Nuclear Double- \beta Decay Phenomenology

Energy Technology Data Exchange (ETDEWEB)

Shanahan, Phiala E.; Tiburzi, Brian C.; Wagman, Michael L.; Winter, Frank; Chang, Emmanuel; Davoudi, Zohreh; Detmold, William; Orginos, Kostas; Savage, Martin J.

2017-08-01

The potential importance of short-distance nuclear effects in double-$\\beta$ decay is assessed using a lattice QCD calculation of the $nn\\rightarrow pp$ transition and effective field theory methods. At the unphysical quark masses used in the numerical computation, these effects, encoded in the isotensor axial polarisability, are found to be of similar magnitude to the nuclear modification of the single axial current, which phenomenologically is the quenching of the axial charge used in nuclear many-body calculations. This finding suggests that nuclear models for neutrinoful and neutrinoless double-$\\beta$ decays should incorporate this previously neglected contribution if they are to provide reliable guidance for next-generation neutrinoless double-$\\beta$ decay searches. The prospects of constraining the isotensor axial polarisabilities of nuclei using lattice QCD input into nuclear many-body calculations are discussed.

Method and apparatus for induced nuclear beta decay

International Nuclear Information System (INIS)

Reiss, H.

1986-01-01

This invention relates to a method and apparatus for inducing beta decay transition that are normally inhibited by angular momentum or parity considerations. According to one aspect of this invention a method of inducing nuclear beta decay transition comprises providing a medium which includes atomic nuclei that have forbidden beta decay transition in which the initial and final nuclear states do not have the same intrinsic parity or have total angular momenta which differ by more than one quantum unit of angular momentum, and applying to the medium an electromagnetic field which has an intensity sufficient to provide the angular momentum or intrinsic parity necessary to overcome the forbiddenness of the beta decay transition of the atomic nuclei, thereby to induce the beta decay transitions. According to another aspect of this invention an apparatus for inducing beta decay transition comprises a medium which includes atomic nuclei that have forbidden beta decay transitions in which the initial and final nuclear states do not have the same intrinsic parity or have total angular momenta which differ by more than one quantum unit of angular momentum, field producing means for producing an electromagnetic field in the medium and means for energising the field producing means to establish the field at an intensity sufficient to provide the angular momentum or intrinsic parity necessary to overcome the forbiddenness of the beta decay transitions of the atomic nuclei. The energy released in these induced nuclear transition is useful for the controlled production of power. The induced beta dacay transitions are also useful to reduce the halflives of long-lived fission product wastes from conventional nuclear fission power plants

Isospin and quarks in nuclear beta-decay

International Nuclear Information System (INIS)

Wilkinson, D.H.

1991-04-01

This paper exposes in some detail the technical problems relating to the extraction of the vector coupling constant from the beta decay of complex nuclei. It also considers the extraction of the axial coupling constant from the beta-decay of the neutron. The internal consistency of all data relating to beta-decay, including that of the muon, is also examined, within the standard model, with a view to the possible intervention of W R . (Author) 52 refs., 4 figs., 2 tabs

A large scale double beta and dark matter experiment: On the physics potential of GENIUS

International Nuclear Information System (INIS)

Klapdor-Kleingrothaus, H.V.; Hirsch, M.

1997-01-01

The physics potential of GENIUS, a recently proposed double beta decay anddark matter experiment is discussed. The experiment will allow to probe neutrino masses down to 10 -(2-3) eV. GENIUS will test the structure of the neutrino mass matrix, and therefore implicitly neutrino oscillation parameters comparable or superior in sensitivity to the best proposed dedicated terrestrial neutrino oscillation experiments. If the 10 -3 eV level is reached, GENIUS will even allow to test the large angle MSW solution of the solar neutrino problem. Even in its first stage GENIUS will confirm or rule out degenerate or inverted neutrino mass scenarios, which have been widely discussed in the literature as a possible solution to current hints on finite neutrino masses and also test the ν e ν μ hypothesis of the atmospheric neutrino problem.GENIUS would contribute to the search for R-parity violating SUSY and right-handed W-bosons on a scale similar or superior to LHC. In addition, GENIUS would largely improve the current 0νββ decay searches for R-parity conserving SUSY and leptoquarks. Concerning cold dark matter (CDM) search, the low background anticipated for GENIUS would, for thefirst time ever, allow to cover the complete MSSM neutralino parameter space, making GENIUS competitive to LHC in SUSY discovery. If GENIUS could find SUSY CDM as a by-product it would confirm that R-parity must be conserved exactly. GENIUS will thus be a major tool for future non-accelerator particle physics. (orig.)

A detection system for very low-energy protons from {beta}-delayed proton decay

Energy Technology Data Exchange (ETDEWEB)

Spiridon, A.; Pollacco, E.; Trache, L.; Simmons, E.; McCleskey, M.; Roeder, B. T.; Tribble, R. E.; Pascovici, G.; Riallot, M.; Mols, J. P.; Kebbiri, M. [Cyclotron Institute, Texas A and M University, College Station, TX 77843-3366 (United States); CEA/IRFU Saclay, Gif-sur-Yvette (France); Cyclotron Institute, Texas A and M University, College Station, TX 77843-3366 (United States); Institut fuer Kernphysik der Universitaet zu Koeln, D-50937 Koeln (Germany); CEA/IRFU Saclay, Gif-sur-Yvette (France)

2012-11-20

We have recently developed a gas based detection system called AstroBox, motivated by nuclear astrophysics studies. The goal was to detect very low-energy protons from {beta}-delayed p-decay with reduced beta background and improved energy resolution. The detector was tested using the {beta}-delayed proton-emitter 23Al previously studied with a set-up based on thin double-sided Si strip detectors. The proton spectrum obtained with AstroBox showed no beta background down to {approx}80 keV. The low energy (206 keV, 267 keV) proton peaks were positively identified, well separated, and the resolution was improved.

Excitation functions of proton-induced reactions on natural Nd and production of radionuclides relevant for double beta decay: Completing measurement in 5-35 MeV energy range

Czech Academy of Sciences Publication Activity Database

Lebeda, Ondřej; Lozza, V.; Petzoldt, J.; Štursa, Jan; Zdychová, Vlasta; Zuber, K.

2014-01-01

Roč. 929, SEP (2014), s. 129-142 ISSN 0375-9474 R&D Projects: GA MŠk(XE) LM2011019 Institutional support: RVO:61389005 Keywords : proton activation * double beta decay * cross-section * production rates * natural neodymium Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 2.202, year: 2014

Beta-decay rate and beta-delayed neutron emission probability of improved gross theory

Science.gov (United States)

Koura, Hiroyuki

2014-09-01

A theoretical study has been carried out on beta-decay rate and beta-delayed neutron emission probability. The gross theory of the beta decay is based on an idea of the sum rule of the beta-decay strength function, and has succeeded in describing beta-decay half-lives of nuclei overall nuclear mass region. The gross theory includes not only the allowed transition as the Fermi and the Gamow-Teller, but also the first-forbidden transition. In this work, some improvements are introduced as the nuclear shell correction on nuclear level densities and the nuclear deformation for nuclear strength functions, those effects were not included in the original gross theory. The shell energy and the nuclear deformation for unmeasured nuclei are adopted from the KTUY nuclear mass formula, which is based on the spherical-basis method. Considering the properties of the integrated Fermi function, we can roughly categorized energy region of excited-state of a daughter nucleus into three regions: a highly-excited energy region, which fully affect a delayed neutron probability, a middle energy region, which is estimated to contribute the decay heat, and a region neighboring the ground-state, which determines the beta-decay rate. Some results will be given in the presentation. A theoretical study has been carried out on beta-decay rate and beta-delayed neutron emission probability. The gross theory of the beta decay is based on an idea of the sum rule of the beta-decay strength function, and has succeeded in describing beta-decay half-lives of nuclei overall nuclear mass region. The gross theory includes not only the allowed transition as the Fermi and the Gamow-Teller, but also the first-forbidden transition. In this work, some improvements are introduced as the nuclear shell correction on nuclear level densities and the nuclear deformation for nuclear strength functions, those effects were not included in the original gross theory. The shell energy and the nuclear deformation for

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

International Nuclear Information System (INIS)

Ouellet, Jonathan Loren

2015-01-01

This thesis describes the design, operation and results of an experimental search for neutrinoless double beta decay (0νββ) of 130 Te 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 130 Te 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 130 Te and operates in the Laboratori Nazionali del Gran Sasso lab in Italy from 2013-2015. The results presented here are based on a nat TeO 2 exposure of 35.2 kg·yr, or 9.8 kg·yr exposure of 130 Te collected between 2013-2015. We see no evidence of 0νββ and place an upper limit on the 0νββ decay rate of Γ 0νββ <0.25x10 24 yr 1 (90 % C.L.), corresponding to a lower limit on the half-life of T 1/2 0ν >2.8x10 24 yr (90 % C.L.). We combine the present result with the results of previous searches in 130 Te. Combining it with the 1.2 kg·Te exposure from the Three Towers Test run we place a half-life limit of T 1/2 03 ν>3.3x10 24 yr (90 % C.L.). And combining these results with the 19.75 kg·yr 130 Te exposure from Cuoricino, we place the strongest limit on the 0νββ half-life of 130 Te to date, at T 1/2 0ν >4.5x10 24 yr (90 % C.L.). Using the present nuclear matrix element calculations for 130 Te, this result corresponds to a 90 % upper limit range on the effective Majorana mass of m ββ <250-710 meV.

Beta and muon decays

International Nuclear Information System (INIS)

Galindo, A.; Pascual, P.

1967-01-01

These notes represent a series of lectures delivered by the authors in the Junta de Energia Nuclear, during the Spring term of 1965. They were devoted to graduate students interested in the Theory of Elementary Particles. Special emphasis was focussed into the computational problems. Chapter I is a review of basic principles (Dirac equation, transition probabilities, final state interactions.) which will be needed later. In Chapter II the four-fermion punctual Interaction is discussed, Chapter III is devoted to the study of beta-decay; the main emphasis is given to the deduction of the formulae corresponding to electron-antineutrino correlation, electron energy spectrum, lifetimes, asymmetry of electrons emitted from polarized nuclei, electron and neutrino polarization and time reversal invariance in beta decay. In Chapter IV we deal with the decay of polarized muons with radiative corrections. Chapter V is devoted to an introduction to C.V.C. theory. (Author)

Beta and muon decays

Energy Technology Data Exchange (ETDEWEB)

Galindo, A; Pascual, P

1967-07-01

These notes represent a series of lectures delivered by the authors in the Junta de Energia Nuclear, during the Spring term of 1965. They were devoted to graduate students interested in the Theory of Elementary Particles. Special emphasis was focussed into the computational problems. Chapter I is a review of basic principles (Dirac equation, transition probabilities, final state interactions.) which will be needed later. In Chapter II the four-fermion punctual Interaction is discussed, Chapter III is devoted to the study of beta-decay; the main emphasis is given to the deduction of the formulae corresponding to electron-antineutrino correlation, electron energy spectrum, lifetimes, asymmetry of electrons emitted from polarized nuclei, electron and neutrino polarization and time reversal invariance in beta decay. In Chapter IV we deal with the decay of polarized muons with radiative corrections. Chapter V is devoted to an introduction to C.V.C. theory. (Author)

Pionic Contribution to Neutrinoless Double Beta Decay

CERN Document Server

Vergados, J D; Toki, H

2010-01-01

It is well known that neutrinoless double decay is going to play a crucial role in settling the neutrino properties, which cannot be extracted from the neutrino oscillation data. It is, in particular, expected to settle the absolute scale of neutrino mass and determine whether the neutrinos are Majorana particles, i.e. they coincide with their own antiparticles. In order to extract the average neutrino mass from the data one must be able to estimate the contribution all possible high mass intermediate particles. The latter, which occur in practically all extensions of the standard model, can, in principle, be differentiated from the usual mass term, if data from various targets are available. One, however, must first be able reliably calculate the corresponding nuclear matrix elements. Such calculations are extremely difficult since the effective transition operators are very short ranged. For such operators processes like pionic contributions, which are usually negligible, turn out to be dominant. We study s...

Gaseous time projection chambers for rare event detection: results from the T-REX project. I. Double beta decay

Energy Technology Data Exchange (ETDEWEB)

Irastorza, I.G.; Aznar, F.; Castel, J., E-mail: igor.irastorza@cern.ch, E-mail: faznar@unizar.es, E-mail: jfcastel@unizar.es [Grupo de Física Nuclear y Astropartículas, Departamento de Física Teórica, Universidad de Zaragoza, C/ P. Cerbuna 12, Zaragoza, 50009 (Spain); and others

2016-01-01

As part of the T-REX project, a number of R and D and prototyping activities have been carried out during the last years to explore the applicability of gaseous Time Projection Chambers (TPCs) with Micromesh Gas Structures (Micromegas) in rare event searches like double beta decay, axion research and low-mass WIMP searches. In both this and its companion paper, we compile the main results of the project and give an outlook of application prospects for this detection technique. While in the companion paper we focus on axions and WIMPs, in this paper we focus on the results regarding the measurement of the double beta decay (DBD) of {sup 136}Xe in a high pressure Xe (HPXe) TPC. Micromegas of the microbulk type have been extensively studied in high pressure Xe and Xe mixtures. Particularly relevant are the results obtained in Xe + trimethylamine (TMA) mixtures, showing very promising results in terms of gain, stability of operation, and energy resolution at high pressures up to 10 bar. The addition of TMA at levels of ∼ 1% reduces electron diffusion by up to a factor of 10 with respect to pure Xe, improving the quality of the topological pattern, with a positive impact on the discrimination capability. Operation with a medium size prototype of 30 cm diameter and 38 cm of drift (holding about 1 kg of Xe at 10 bar in the fiducial volume, enough to contain high energy electron tracks in the detector volume) has allowed to test the detection concept in realistic experimental conditions. Microbulk Micromegas are able to image the DBD ionization signature with high quality while, at the same time, measuring its energy deposition with a resolution of at least a ∼ 3% FWHM @ Q{sub ββ}. This value was experimentally demonstrated for high-energy extended tracks at 10 bar, and is probably improvable down to the ∼ 1% FWHM levels as extrapolated from low energy events. In addition, first results on the topological signature information (one straggling track ending in two

Precision study of the $\\beta$-decay of $^{74}$Rb

CERN Multimedia

Van Duppen, P L E; Lunney, D

2002-01-01

We are proposing a high-resolution study of the $\\beta$-decay of $^{74}$Rb in order to extrapolate our precision knowledge of the superallowed $\\beta$-decays from the sd and fp shells towards the medium-heavy Z=N nuclei. The primary goal is to provide new data for testing the CVC hypothesis and the unitarity condition of the CKM matrix of the Standard Model. The presented programme would involve the careful measurements of the decay properties of $^{74}$Rb including the branching ratios to the excited states as well as the precise determination of the decay energy of $^{74}$Rb. The experimental methods readily available at ISOLDE include high-transmission conversion electron spectroscopy, $\\gamma$-ray spectroscopy as well as the measurements of the masses of $^{74}$Rb and $^{74}$Kr using two complementary techniques, ISOLTRAP and MISTRAL. The experiment would rely on a high-quality $^{74}$Rb beam available at ISOLDE with adequate intensity.

First scintillating bolometer tests of a CLYMENE R&D on Li2MoO4 scintillators towards a large-scale double-beta decay experiment

Science.gov (United States)

Buşe, G.; Giuliani, A.; de Marcillac, P.; Marnieros, S.; Nones, C.; Novati, V.; Olivieri, E.; Poda, D. V.; Redon, T.; Sand, J.-B.; Veber, P.; Velázquez, M.; Zolotarova, A. S.

2018-05-01

A new R&D on lithium molybdate scintillators has begun within a project CLYMENE (Czochralski growth of Li2MoO4 crYstals for the scintillating boloMeters used in the rare EveNts sEarches). One of the main goals of the CLYMENE is a realization of a Li2MoO4 crystal growth line to be complementary to the one recently developed by LUMINEU in view of a mass production capacity for CUPID, a next-generation tonne-scale bolometric experiment to search for neutrinoless double-beta decay. In the present paper we report the investigation of performance and radiopurity of 158-g and 13.5-g scintillating bolometers based on a first large-mass (230 g) Li2MoO4 crystal scintillator developed within the CLYMENE project. In particular, a good energy resolution (2-7 keV FWHM in the energy range of 0.2-5 MeV), one of the highest light yield (0.97 keV/MeV) amongst Li2MoO4 scintillating bolometers, an efficient alpha particles discrimination (10 σ) and potentially low internal radioactive contamination (below 0.2-0.3 mBq/kg of U/Th, but 1.4 mBq/kg of 210Po) demonstrate prospects of the CLYMENE in the development of high quality and radiopure Li2MoO4 scintillators for CUPID.

Precision Study of the $\\beta$-decay of $^{62}$Ga

CERN Multimedia

2002-01-01

It is proposed to perform a precision study of the $\\beta$-decay of $\\,^{62}$Ga taking advantage of recent developments of the ISOLDE Laser Ion Source. The goal is to eventually extend the high-precision knowledge of superallowed $\\beta$-decays beyond the nine decays that presently are used for extracting the V$_{ud}$ quark mixing matrix element of the CKM matrix. The scientific motivations are the current deviation of more than 2$\\sigma$ of the unitary condition of this matrix, which could be an indication of non-standard-model physics, and a test of the theoretical corrections applied to the experimental data. The experiment will utilise the Total Absorption $\\gamma$-ray (TAG) spectrometer in order to determine weak branchings to excited states in $^{62}$Zn and the ISOLDE spectroscopy station to perform half-life measurements and detailed spectroscopy of this nucleus.

The MAJORANA Experiment

Energy Technology Data Exchange (ETDEWEB)

Aguayo Navarrete, Estanislao; Avignone, F. T.; Back, Henning O.; Barabash, Alexander S.; Bergevin, M.; 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, Peter J.; Efremenko, Yuri; Egorov, Viatcheslav; Ejiri, H.; Elliott, Steven R.; Esterline, James H.; Fast, James E.; Fields, N.; Finnerty, P.; Fraenkle, Florian; Gehman, Victor M.; Giovanetti, G. K.; Green, Matthew P.; Guiseppe, Vincente; Gusey, K.; Hallin, A. L.; Hazama, R.; Henning, R.; Hime, Andrew; Hoppe, Eric W.; Horton, Mark; Howard, Stanley; Howe, M. A.; Johnson, R. A.; Keeter, K.; Keillor, Martin E.; Keller, C.; Kephart, Jeremy D.; Kidd, Mary; Knecht, A.; Kochetov, Oleg; Konovalov, S.; Kouzes, Richard T.; LaFerriere, Brian D.; LaRoque, B. H.; Leon, Jonathan D.; Leviner, L.; Loach, J. C.; MacMullin, S.; Marino, Michael G.; Martin, R. D.; Mei, Dong-Ming; Merriman, Jason H.; Miller, M. L.; Mizouni, Leila; Nomachi, Masaharu; Orrell, John L.; Overman, Nicole R.; Phillips, D.; Poon, Alan; Perumpilly, Gopakumar; Prior, Gersende; Radford, D. C.; Rielage, Keith; Robertson, R. G. H.; Ronquest, M. C.; Schubert, Alexis G.; Shima, T.; Shirchenko, M.; Snavely, Kyle J.; Sobolev, V.; Steele, David; Strain, J.; Thomas, K.; Timkin, V.; Tornow, W.; Vanyushin, I.; Varner, R. L.; Vetter, Kai; Vorren, Kris R.; Wilkerson, John; Wolfe, B. A.; Yakushev, E.; Young, A.; Yu, Chang-Hong; Yumatov, Vladimir; Zhang, C.

2011-10-01

The Majorana collaboration is actively pursuing research and development aimed at a tonne-scale {sup 76}Ge neutrinoless double-beta decay ({beta}{beta}(0{nu})-decay) experiment. The current, primary focus is the construction of the Majorana Demonstrator experiment, an R and D effort that will field approximately 40 kg of germanium detectors with mixed enrichment levels. This article provides a status update on the construction of the Demonstrator.

Determination of the Electron Neutrino Mass from Experiments on Electron-Capture Beta-Decay (EC)

CERN Multimedia

2002-01-01

The aim of the programme is to measure the electron-neutrino mass, for which at present an upper limit of 500~eV is known. \\\\ \\\\ The experiment studies the shape of the internal bremsstrahlung spectrum in electron-capture near its upper end-point and deduces a mass from small shape changes completely analogous to those in the well-known determination of the electron antineutrino mass in the tritium beta-minus decay. \\\\ \\\\ In a low-energy bremsstrahlung process, the capture takes place from a virtual S state associated with a radiative P~@A~S electromagnetic transition, and the resonant nature of the process leads to important enhancements of the photon intensities at low energy, in particular near the resonance energies co (X-rays). This effect gives this type of experiment a chance to compete with experiments on continuous beta spectra. \\\\ \\\\ The programme concentrates on two long-lived isotopes: \\\\ \\\\ 1)~~|1|6|3Ho. The Q value for this isotope has been found to be 2.6-2.7 keV. A detector specially construct...

Radiative corrections to light neutrino masses in low scale type I seesaw scenarios and neutrinoless double beta decay

Energy Technology Data Exchange (ETDEWEB)

Lopez-Pavon, J. [SISSA and INFN - sezione di Trieste, via Bonomea 265, 34136 Trieste (Italy); Molinaro, E. [CP-Origins and Danish Institute for Advanced Study, University of Southern Denmark,Campusvej 55, DK-5230 Odense M (Denmark); Petcov, S.T. [SISSA and INFN - sezione di Trieste, via Bonomea 265, 34136 Trieste (Italy); Kavli IPMU (WPI), University of Tokyo, 5-1-5 Kashiwanoha, 277-8583 Kashiwa (Japan)

2015-11-05

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.

Geochemical evidence of the double β decay of 100Mo

International Nuclear Information System (INIS)

Hidaka, Hiroshi; Ly, Chi V.; Suzuki, Katsuhiko

2004-01-01

Enrichment of the 100 Ru isotope, resulting from the double beta (ββ) decay of 100 Mo, has been found in old molybdenites from Australia. Using Re-Os ages determined here together with the amount of excess 100 Ru determined via isotope dilution mass spectrometry, consistent half-lives were obtained from two different molybdenite samples of varying ages (2.90 billion and 1.05 billion years old) with an average half-life of (2.1±0.3)x10 18 years. This half-life is highly consistent with the theoretical model for a two-neutrino ββ decay

An assessment of anti-neutrino mass determination via electrostatic measurements of tritium beta-decay

International Nuclear Information System (INIS)

Le Bas, P.A.

1984-01-01

Data on the mass of the anti-neutrino determined via electrostatic measurements of tritium beta-decay are assessed. Relativistic calculations concerning the finite mass of the electron anti-neutrino and the recoil of the nucleus, are given for the theoretical end-point spectrum of tritium beta-decay. The specifications are given for an electrostatic Spherical Retarding Beta-Spectrometer, and an electrostatic Cylindrical Mirror Analyser, both used in the tritium beta-decay experiment. The electrostatic measurements lead to a value of less than 50 ev (90% C.L.) for the electron anti-neutrino mass. These results are discussed in terms of the resolution of the electrostatic equipment and the Monte Carlo simulations of the data collection. (UK)

JENDL FP decay data file 2000 and the beta-decay theory

International Nuclear Information System (INIS)

Yoshida, Tadashi; Katakura, Jun Ichi; Tachibana, Takahiro

2002-01-01

JENDL FP Decay Data File 2000 has been developed as one of the special purpose files of the Japanese Evaluated Nuclear Data Library (JENDL), which constitutes a versatile nuclear data basis for science and technology. In the format of ENDF-6 this file includes the decay data for 1087 unstable fission product (FP) nuclides and 142 stable nuclides as their daughters. The primary purpose of this file is to use in the summation calculation of FP decay heat, which plays a critical role in nuclear safety analysis; the loss-of-coolant accident analysis of reactors, for example. The data for a given nuclide are its decay modes, the Q value, the branching ratios, the average energies released in the form of beta- and gamma-rays per decay, and their spectral data. The primary source of the decay data adopted here is the ENSDF (Evaluated Nuclear Structure Data File). The data in ENSDF, however, cover only the measured values. The data of the short-lived nuclides, which are essential for the decay heat calculations at short cooling times, are often fully lacking or incomplete even if they exist. This is mainly because of their short half-life nature. For such nuclides a theoretical model calculation is applied in order to fill the gaps between the true and the experimentally known decay schemes. In practice we have to predict the average decay energies and the spectral data for a lot of short-lived FPs by use of beta-decay theories. Thus the beta-decay theory plays a very important role in generating the FP decay data file

Beta decay of 22O

International Nuclear Information System (INIS)

Hubert, F.; Dufour, J.P.; Moral, R. del; Fleury, A.; Jean, D.; Pravikoff, M.S.; Delagrange, H.; Geissel, H.; Schmidt, K.H.; Hanelt, E.

1989-01-01

The beta-gamma spectroscopic study of 22 O is presented. This nucleus, produced as a projectile-like fragment from the interaction of a 60 MeV/n 40 Ar beam with a Be target, has been separated by the LISE spectrometer. Several gamma rays from 22 O decay have been observed, from which a half-life of (2.25±0.15) s has been determined. Accurate excitation energies have been deduced for several states in 22 F. A partial beta decay scheme of 22 O has been established. Experimental results have been compared with shell model calculations. (orig.)

Precision measurements in nuclear beta decay

Energy Technology Data Exchange (ETDEWEB)

Naviliat-Cuncic, Oscar, E-mail: naviliat@nscl.msu.edu [Michigan State University, National Superconducting Cyclotron Laboratory and Department of Physics and Astronomy (United States)

2013-03-15

Precision measurements in nuclear beta decay provide sensitive means to determine the fundamental coupling of charged fermions to weak bosons and to test discrete symmetries in the weak interaction. The main motivation of such measurements is to find deviations from Standard Model predictions as possible indications of new physics. I focus here on two topics related to precision measurements in beta decay, namely: (i) the determination of the V{sub ud} element of the Cabibbo-Kobayashi-Maskawa quark mixing matrix from nuclear mirror transitions and (ii) selected measurements of time reversal violating correlations in nuclear and neutron decays. These topics complement those presented in other contributions to this conference.

Background analysis for the beta-spectrum of the isotope 113Cd in the COBRA experiment

Energy Technology Data Exchange (ETDEWEB)

Platzek, Stephan [Technische Universitaet Dresden (Germany); Collaboration: COBRA-Collaboration

2016-07-01

The COBRA experiment uses Cadmium-Zinc-Telluride as detector material. This semiconductor contains several isotopes that are candidates for neutrinoless double beta-decay. Due to the natural abundance of the detector material various other isotopes are present as well. One of them is {sup 113}Cd with an abundance of about 12%. The fourfold forbidden non-unique beta-decay of {sup 113}Cd is a rare process with a half-life of about 8.10{sup 15} years. The shape of the spectrum is still topic of scientific discussions because of various forecasts given by theoretical models. The signal related to this decay is by far the most prominent in the COBRA setup causing more than 98% of the total rate. In this talk potential background components contributing to the {sup 113}Cd beta-spectrum are discussed with the aim to develop a detailed background simulation with the program VENOM (based on Geant4), that includes background sources originating from cosmic activation as well as natural radioactivity and detector specific effects.

Proposed experimental test of Bell's inequality in nuclear beta decay

International Nuclear Information System (INIS)

Skalsey, M.

1986-01-01

A β decay experiment is proposed for testing Bell's inequality, related to hidden-variables alternatives to quantum mechanics. The experiment uses Mott scattering for spin polarization analysis of internal conversion electrons. Beta-decay electrons, in cascade with the conversion electrons, are longitudinally polarized due to parity violation in the weak interaction. So simply detecting the β electron direction effectively measures the spin. A two-particle spin-spin correlation can thus be investigated and related, within certain assumptions, to Bell's inequality. The example of 203 Hg decay is used for a calculation of expected results. Specific problems related to nuclear structure and experimental inconsistencies are also discussed

Study of octupole deformation in n-rich Ba isotopes populated via $\\beta$-decay

CERN Multimedia

We propose to exploit the unique capability of the ISOLDE facility to produce $^{150, 151, 152}$Cs beams to investigate their radioactive $\\beta$-decay to $^{150, 151, 152}$Ba. The interest to study this mass region is twofold: these nuclei are expected to show octupole deformations already in their low-lying state, secondly information on the $\\beta$-decay is needed for the nuclear astrophysical model. The experiment will be performed with the ISOLDE Decay Station (IDS) setup using the fast tape station of K.U.-Leuven, equipped with four Clover Germanium detectors, four LaBr$_{3}$(Ce) detectors and one LEP HPGe detector. Information on the $\\beta$-decay, such as lifetimes and delayed neutron-emission probabilities, will be extracted, together with the detailed spectroscopy of the daughter nuclei, via $\\gamma$-$\\gamma$-coincidences and lifetime measurement of specific states.

Double-β decay Q value of 150Nd

International Nuclear Information System (INIS)

Kolhinen, V. S.; Eronen, T.; Gorelov, D.; Hakala, J.; Jokinen, A.; Kankainen, A.; Moore, I. D.; Rissanen, J.; Saastamoinen, A.; Suhonen, J.; Aeystoe, J.

2010-01-01

The double-β decay Q value of 150 Nd was determined by using the JYFLTRAP Penning trap mass spectrometer. The measured mass difference between 150 Nd and 150 Sm is 3371.38(20) keV. This new value deviates by 3.7 keV from the previously adopted value of 3367.7(22) keV and is a factor of 10 more precise. Accurate knowledge of this Q value is important because 150 Nd is a primary candidate to be used in the search for neutrinoless double-β decay modes in several experiments.

Extending two Higgs doublet models for two-loop neutrino mass generation and one-loop neutrinoless double beta decay

Directory of Open Access Journals (Sweden)

Zhen Liu

2017-02-01

Full Text Available We extend some two Higgs doublet models, where the Yukawa couplings for the charged fermion mass generation only involve one Higgs doublet, by two singlet scalars respectively carrying a singly electric charge and a doubly electric charge. The doublet and singlet scalars together can mediate a two-loop diagram to generate a tiny Majorana mass matrix of the standard model neutrinos. Remarkably, the structure of the neutrino mass matrix is fully determined by the symmetric Yukawa couplings of the doubly charged scalar to the right-handed leptons. Meanwhile, a one-loop induced neutrinoless double beta decay can arrive at a testable level even if the electron neutrino has an extremely small Majorana mass. We also study other experimental constraints and implications including some rare processes and Higgs phenomenology.

Extending two Higgs doublet models for two-loop neutrino mass generation and one-loop neutrinoless double beta decay

Energy Technology Data Exchange (ETDEWEB)

Liu, Zhen, E-mail: liu-zhen@sjtu.edu.cn; Gu, Pei-Hong, E-mail: peihong.gu@sjtu.edu.cn

2017-02-15

We extend some two Higgs doublet models, where the Yukawa couplings for the charged fermion mass generation only involve one Higgs doublet, by two singlet scalars respectively carrying a singly electric charge and a doubly electric charge. The doublet and singlet scalars together can mediate a two-loop diagram to generate a tiny Majorana mass matrix of the standard model neutrinos. Remarkably, the structure of the neutrino mass matrix is fully determined by the symmetric Yukawa couplings of the doubly charged scalar to the right-handed leptons. Meanwhile, a one-loop induced neutrinoless double beta decay can arrive at a testable level even if the electron neutrino has an extremely small Majorana mass. We also study other experimental constraints and implications including some rare processes and Higgs phenomenology.

Sizeable beta-strength in ³¹Ar ^{(beta 3p) decay}

DEFF Research Database (Denmark)

T. Koldste, G.; Blank, B.; J. G. Borge, M.

2014-01-01

We present for the first time precise spectroscopic information on the recently discovered decay mode beta-delayed 3p-emission. The detection of the 3p events gives an increased sensitivity to the high energy part of the Gamow-Teller strength distribution from the decay of 31Ar revealing that as ...... that as much as 30% of the strength resides in the beta-3p decay mode. A simplified description of how the main decay modes evolve as the excitation energy increases in 31Cl is provided....

On the Proton Spectrum in Free Neutron beta-decay

CERN Document Server

Bunatian, G G

2000-01-01

We consider the calculations which are appropriate to acquire with a high precision, of ~1% or better, the general characteristics of weak interactions from the experiments on the free neutron beta-decay; the principle emphasis is placed on the phenomena associated with the recoil of protons. The part played by electromagnetic interactions in beta-decay is visualized, with special attention drawn to the influence of the gamma-radiation on the momentum distribution of the particles in the final state. The effect of electromagnetic interactions on the proton recoil spectrum is studied, in the light of the experiments which are carried out and planned for now. The results of the calculations, which are to be confronted with the experimental data, are presented upright in terms of the effective Lagrangian underlying the inquiry. Owing to electromagnetic interactions, the corrections to the energy distribution of protons prove to amount to the value of a few per cent. Nowadays, this is substantial to obtain with a...

Beta decay of Cu-56

NARCIS (Netherlands)

Borcea, R; Aysto, J; Caurier, E; Dendooven, P; Doring, J; Gierlik, M; Gorska, M; Grawe, H; Hellstrom, M; Janas, Z; Jokinen, A; Karny, M; Kirchner, R; La Commara, M; Langanke, K; Martinez-Pinedo, G; Mayet, P; Nieminen, A; Nowacki, F; Penttila, H; Plochocki, A; Rejmund, M; Roeckl, E; Schlegel, C; Schmidt, K; Schwengner, R; Sawicka, M

2001-01-01

The proton-rich isotope Cu-56 was produced at the GSI On-Line Mass Separator by means of the Si-28(S-32, p3n) fusion-evaporation reaction. Its beta -decay properties were studied by detecting beta -delayed gamma rays and protons. A half-Life of 93 +/- 3 ms was determined for Cu-56. Compared to the

Beta-decay of {sup 56}Cu

Energy Technology Data Exchange (ETDEWEB)

Ramdhane, M.; Baumann, P.; Knipper, A.; Walter, G. [Institute de Recherches Subatomiques, 67 - Strasbourg (France); Janas, Z.; Plochocki, A. [Warsaw Univ. (Poland). Inst. of Experimental Physics; Aeystoe, J.; Dendooven, P.; Jokinen, A.; Oinonen, M.; Pentilae, H. [Jyvaeskylae Univ. (Finland); Liu, W.; Grawe, H.; Hu, Z.; Kirchner, R.; Klepper, O.; Roeckl, E. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany); Gorska, M. [Warsaw Univ. (Poland). Inst. of Experimental Physics]|[Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany); Fujita, Y. [Osaka Univ. (Japan); Brown, B.A. [Michigan State Univ., East Lansing, MI (United States)

1998-02-01

By measuring positrons and {beta}-delayed {gamma}-rays emitted from mass-separated sources, the decay of {sup 56}Cu(4{sup +},T{sub z}=-1,T=1) to states in the doubly-magic nucleus {sup 56}Ni was studied for the first time. The half-life of {sup 56}Cu was measured to be 78(15) ms, and four {beta}-delayed {gamma}-rays were assigned to its decay. The resulting experimental data on Fermi and Gamow-Teller strength are compared with shell-model predictions. (orig.)

The relative importance of relativistic induced interactions in the beta decay of 170Tm

International Nuclear Information System (INIS)

Bogdan, D.; Cristu, M.I.; Holan, S.; Faessler, A.

1982-09-01

The log ft-values, the spectrum shape functions, and the beta-gamma angular correlation coefficients of the 170 Tm beta decay are computed in the framework of relativistic formfactor formalism using asymmetric rotor model wavefunctions. Main vector and axial vector hadron currents being strongly hindered, the relative importance of induced interaction matrix elements is accurately estimated. Good agreement with experiment is obtained for the beta decay observables when the main induced interaction terms were taken into account. The contribution of the pseudoscalar term was found insignificant. (authors)

Nuclear transparency and double beta decay of molybdenum 100. Annual progress report, February 1, 1994--January 31, 1995

International Nuclear Information System (INIS)

Nicholson, H.W.

1994-07-01

During the past year, work has been nearly completed on a Physical Review paper with final results of a search for neutrinoless double-β decay of molybdenum 100 with collaborators from LBL, the University of New Mexico, and the Idaho Engineering Laboratory. Major part of this work was to carry out an extensive statistical analysis of the data. During the spring of 1994, Sean Sutton spent the majority of this time at Orsay, France working on NEMO 3, a next generation double-β decay experiment involving molybdenum 100 and other isotopes. Nicholson and Sutton have designed and built a scintillating fiber hadoscope used in the May--July AGS high energy physics run at BNL in AGS experiment 850 to measure color transparency. Professor Nicholson has had primary responsibility for the design, construction, and installation of this hodoscope and for overseeing the construction and installation of two scintillating counter upstream hodoscopes. To date, the fiber hodoscope had handled total beam rates exceeding 20 MHz with beam rates as high as 10 MHz on a single fiber. Light intensification and readout electronics to be used in the CsI(Tl) calorimeter in the SLAC B factory has just begun this summer

Neutrinoless Double Beta Decay Matrix Elements in Light Nuclei

Energy Technology Data Exchange (ETDEWEB)

Pastore, S.; Carlson, J.; Cirigliano, V.; Dekens, W.; Mereghetti, E.; Wiringa, R. B.

2018-01-17

We present the first ab initio calculations of neutrinoless double-β decay matrix elements in A=6-12 nuclei using variational Monte Carlo wave functions obtained from the Argonne v₁₈ two-nucleon potential and Illinois-7 three-nucleon interaction. We study both light Majorana neutrino exchange and potentials arising from a large class of multi-TeV mechanisms of lepton-number violation. Our results provide benchmarks to be used in testing many-body methods that can be extended to the heavy nuclei of experimental interest. In light nuclei we also study the impact of two-body short-range correlations and the use of different forms for the transition operators, such as those corresponding to different orders in chiral effective theory.

The LPCTrap experiment: measurement of the {beta}-{nu} angular correlation in {sup 6}He{sup +} decay using a transparent Paul trap

Energy Technology Data Exchange (ETDEWEB)

Velten, Ph., E-mail: velten@lpccaen.in2p3.fr; Ban, G.; Durand, D.; Flechard, X.; Lienard, E.; Mauger, F.; Mery, A.; Naviliat-Cuncic, O.; Rodriguez, D.; Thomas, J. C. [Universite de Caen, LPC Caen, ENSICAEN (France)

2011-07-15

The LPCTrap experiment is devoted to the precise measurement of the {beta}-{nu} angular correlation parameter, a{sub {beta}{nu}}, in the pure Gamow-Teller decay of {sup 6}He{sup +}. This experiment is motivated by the search of the presence of tensor type contributions in the weak interaction. The radioactive source is confined in a transparent Paul trap installed at LIRAT, the low energy beam line of the SPIRAL facility. The {beta}-{nu} correlation is studied by measuring the time of flight of the recoil ions detected in coincidence with the {beta} particles. During the last experiment, a total of 4 Multiplication-Sign 10{sup 6} coincidence events have been recorded which would enable to determine the coefficient with a statistical uncertainty of 0.5%. The status of the analysis is presented in this contribution.

Candidate W+Z double leptonic decay event of the ATLAS experiment

CERN Multimedia

ATLAS, Experiment

2014-01-01

Candidate W+Z double leptonic decay event. Candidate for a WZ ->eνμμ decay, collected on 7 October 2010. The invariant mass of the two muons is 96 GeV. The transverse mass of the potential W boson is 57 GeV. Further event properties: PT(μ+) = 65 GeV PT(μ-) = 40 GeV PT(e) = 64 GeV ETmiss = 21 GeV

Beta Decay in the Field of an Electromagnetic Wave and Experiments on Measuring the Neutrino Mass

International Nuclear Information System (INIS)

Dorofeev, O.F.; Lobanov, A.E.

2005-01-01

Investigations of the effect of an electromagnetic wave field on the beta-decay process are used to analyze the tritium-decay experimental data on the neutrino mass. It is shown that the electromagnetic wave can distort the beta spectrum, shifting the end point to the higher energy region. This phenomenon is purely classical and it is associated with the electron acceleration in the radiation field. Since strong magnetic fields exist in setups for precise measurement of the neutrino mass, the indicated field can appear owing to the synchrotron radiation mechanism. The phenomenon under consideration can explain the experimentally observed anomalies in the spectrum of the decay electrons; in particular, the effect of the 'negative square of the neutrino mass'

Study of the $\\beta$-decay of $^{20}$Mg

CERN Multimedia

Cederkall, J A; Riisager, K; Garcia borge, M J; Madurga flores, M; Jonson, B N G; Fynbo, H O U; Koldste, G T; Giles, T J; Nilsson, T; Perea martinez, A

We propose to perform a detailed study of the $\\beta$-decay of the dripline nucleus $^{20}$Mg. This will provide important information on resonances in $^{20}$Na relevant for the astrophysical rp-process as well as improved information for detailed comparison with state-of-the-art Shell-Model calculations and for comparison with the mirror $\\beta$-decay of $^{20}$O.

A neutrino mass-mixing sum rule from SO(10) and neutrinoless double beta decay

Energy Technology Data Exchange (ETDEWEB)

Buccella, F. [INFN, Sezione di Napoli,Complesso University Monte S. Angelo, I-80126 Napoli (Italy); Chianese, M. [INFN, Sezione di Napoli,Complesso University Monte S. Angelo, I-80126 Napoli (Italy); Dipartimento di Fisica Ettore Pancini, Università di Napoli Federico II,Complesso University Monte S. Angelo, I-80126 Napoli (Italy); Mangano, G. [INFN, Sezione di Napoli,Complesso University Monte S. Angelo, I-80126 Napoli (Italy); Miele, G.; Morisi, S.; Santorelli, P. [INFN, Sezione di Napoli,Complesso University Monte S. Angelo, I-80126 Napoli (Italy); Dipartimento di Fisica Ettore Pancini, Università di Napoli Federico II,Complesso University Monte S. Angelo, I-80126 Napoli (Italy)

2017-04-03

Minimal SO(10) grand unified models provide phenomenological predictions for neutrino mass patterns and mixing. These are the outcome of the interplay of several features, namely: i) the seesaw mechanism; ii) the presence of an intermediate scale where B-L gauge symmetry is broken and the right-handed neutrinos acquire a Majorana mass; iii) a symmetric Dirac neutrino mass matrix whose pattern is close to the up-type quark one. In this framework two natural characteristics emerge. Normal neutrino mass hierarchy is the only allowed, and there is an approximate relation involving both light-neutrino masses and mixing parameters. This differs from what occurring when horizontal flavour symmetries are invoked. In this case, in fact, neutrino mixing or mass relations have been separately obtained in literature. In this paper we discuss an example of such comprehensive mixing-mass relation in a specific realization of SO(10) and, in particular, analyse its impact on the expected neutrinoless double beta decay effective mass parameter 〈m{sub ee}〉, and on the neutrino mass scale. Remarkably a lower limit for the lightest neutrino mass is obtained (m{sub lightest}≳7.5×10{sup −4} eV, at 3 σ level).

Simulations of Bunch Merging in a Beta Beam Decay Ring

CERN Document Server

Heinrich, Daniel Christopher; Chance, Antoine

2011-01-01

To further study neutrino oscillation properties a Beta Beam facility has been proposed. Beta decaying ions with high kinetic energy are stored in a storage ring ("Decay Ring") with straight sections to create pure focused (anti) electron neutrino beams. However to reach high sensitivity to neutrino oscillation parameters in the experiment the bunched beam intensity and duty cycle in the DR have to be optimized. The first CERN-based scenario, using 6He and 18Ne as neutrino sources, has been studied using a bunch merging RF scheme. Two RF cavities at different frequencies are used to capture newly injected bunches and then merge them into the stored bunches. It was shown that this scheme could satisfy the requirements on intensity and duty cycle set by the experiment. This merging scheme has now been revised with new simulation software providing new results for 6He and 18Ne. Furthermore bunch merging has been studied for the second CERN-based scenario using 8Li and 8B.

Decay Spectroscopy for Nuclear Astrophysics: {beta}-delayed Proton Decay

Energy Technology Data Exchange (ETDEWEB)

Trache, L.; Simmons, E.; Spiridon, A.; McCleskey, M.; Roeder, B. T.; Tribble, R. E. [Texas A and M University, College Station, TX 77845 (United States); Saastamoinen, A.; Jokinen, A.; Aysto, J. [University of Jyvaskyla, Jyvaskyla (Finland); Davinson, T.; Woods, P. J. [University of Edinburgh, Edinburgh (United Kingdom); Pollacco, E.; Kebbiri, M. [CEA/IRFU Saclay (France); Pascovici, G. [IKP, Universitaet zu Koeln (Germany)

2011-11-30

Decay spectroscopy is one of the oldest indirect methods in nuclear astrophysics. We have developed at TAMU techniques to measure beta- and beta-delayed proton decay of sd-shell, proton-rich nuclei. The short-lived radioactive species are produced in-flight, separated, then slowed down (from about 40 MeV/u) and implanted in the middle of very thin Si detectors. These allowed us to measure protons with energies as low as 200 keV from nuclei with lifetimes of 100 ms or less. At the same time we measure gamma-rays up to 8 MeV with high resolution HPGe detectors. We have studied the decay of {sup 23}Al, {sup 27}P, {sup 31}Cl, all important for understanding explosive H-burning in novae. The technique has shown a remarkable selectivity to beta-delayed charged-particle emission and works even at radioactive beam rates of a few pps. The states populated are resonances for the radiative proton capture reactions {sup 22}Na(p,{gamma}){sup 23}Mg(crucial for the depletion of {sup 22}Na in novae), {sup 26m}Al(p,{gamma}){sup 27}Si and {sup 30}P(p,{gamma}){sup 31}S(bottleneck in novae and XRB burning), respectively. More recently we have radically improved the technique using a gas based detector we call AstroBox.

Double-Exponentially Decayed Photoionization in CREI Effect: Numerical Experiment on 3D H2+

International Nuclear Information System (INIS)

Feng, Li; Ting-Ying, Wang; Gui-Zhong, Zhang; Wang-Hua, Xiang; III, W. T. Hill

2008-01-01

On the platform of the 3D H 2 + system, we perform a numerical simulation of its photoionization rate under excitation of weak to intense laser intensities with varying pulse durations and wavelengths. A novel method is proposed for calculating the photoionization rate: a double exponential decay of ionization probability is best suited for fitting this rate. Confirmation of the well-documented charge-resonance-enhanced ionization (CREI) effect at medium laser intensity and finding of ionization saturation at high light intensity corroborate the robustness of the suggested double-exponential decay process. Surveying the spatial and temporal variations of electron wavefunctions uncovers a mechanism for the double-exponentially decayed photoionization probability as onset of electron ionization along extra degree of freedom. Henceforth, the new method makes clear the origins of peak features in photoionization rate versus internuclear separation. It is believed that this multi-exponentially decayed ionization mechanism is applicable to systems with more degrees of motion

Double γ decay in 90Zr

International Nuclear Information System (INIS)

Mucciolo, E.R.

1988-01-01

The double γ decay between θ + n - θ + i of 90 Zr was observed. The θ + n level was fed through the decay of 90 Sr. The experimental arrangement consisted of a double coincidence system between the two semiconductor detectors. (A.C.A.S.) [pt

Properties of low-lying intruder states in $^{34}$Al and $^{34}$Si sequentially populated in $\\beta$-decay of $^{34}$Mg

CERN Multimedia

A low-lying long-lived (26±1 ms) isomer in $^{34}$Al has been observed recently and assigned as 1$^{+}$ state of intruder character. It was populated in $^{36}$S fragmentation and feeds, in $\\beta$-decay, the 0$_{2}^{+}$ state in $^{34}$Si whose excitation energy and lifetime were determined in an electron-positron pairs spectroscopy experiment. In the present experiment we intend to measure for the first time the $\\gamma$-rays following the $\\beta$-decay of $^{34}$Mg. Despite the interest for $^{34}$Mg, the up-right corner of the “N$\\thicksim$20 island of inversion”, the only information on its $\\beta$-decay is the lifetime of 20±10 ms, determined from $\\beta$-neutron coincidences. As a result of the proposed experiment, we expect to place the first transitions in the level scheme of $^{34}$Al and to strongly populate the newly observed isomer, measuring its excitation energy, if the branching ratio to 4$^{−}$ ground state is significant. Theoretical estimations for the $\\beta$-decay of the new isome...

Study of $\\beta$-delayed neutron decay of $^{8}$He

CERN Multimedia

The goal of the present proposal is to study $\\beta$-delayed neutron decay branch of $^{8}$He. The energy spectra of the emitted neutrons will be measured in the energy range of 0.1 – 6 MeV using the VANDLE spectrometer. Using coincident $\\gamma$-ray measurement, components of the spectrum corresponding to transitions to the ground- and first- excited states of $^{7}$Li will be disentangled. The new data will allow us to get a more complete picture of the $\\beta$-decay of $^{8}$He and to clarify the discrepancy between the B(GT) distributions derived from the $\\beta$-decay and $^{8}$He(p, n)$^{8}$Li reaction studies.

The beta(+) decay and cosmic-ray half-life of Mn-54

Science.gov (United States)

Dacruz, M. T. F.; Norman, E. B.; Chan, Y. D.; Garcia, A.; Larimer, R. M.; Lesko, K. T.; Stokstad, R. G.; Wietfeldt, F. E.

1993-03-01

We performed a search for the beta(+) branch of Mn-54 decay. As a cosmic ray, Mn-54, deprived of its atomic electrons, can decay only via beta(+) and beta(-) decay, with a half-life of the order of 106 yr. This turns Mn-54 into a suitable cosmic chronometer for the study of cosmic-ray confinement times. We searched for coincident back-to-back 511-keV gamma-rays using two germanium detectors inside a Nal(Tl) annulus. An upper limit of 2 x 10-8 was found for the beta(+) decay branch, corresponding to a lower limit of 13.7 for the log ft value.

Status of the double Chooz experiment

Energy Technology Data Exchange (ETDEWEB)

Gonzalez, L.F.G.; Kemp, E. [Universidade Estadual de Campinas (IFGW/UNICAMP), SP (Brazil). Inst. de Fisica Gleb Wataghin. Dept. de Raios Cosmicos e Cronologia; Anjos, J.C. dos; Lima Junior, H.P.; Gama, R.; Abrahao, T.; Pepe, I.M. [Centro Brasileiro de Pesquisas Fisicas (MCT/CBPF), Rio de Janeiro, RJ (Brazil)

2012-07-01

Full text: The neutrino oscillation experiment Double Chooz, located at the nuclear power plant of Chooz (Ardennes, France), has as purpose to measure the mixing angle {theta}{sub 13} with greater precision than the measurement of its predecessor, the Chooz experiment. For this, the Double Chooz experiment will use antineutrinos generated in both Chooz plant reactors and will make high accuracy measurements of the flux in two different baselines with identical gadolinium-doped-scintillator detectors, that uses the inverse-beta-decay positron and neutron detection as an antineutrino signature. This signature is given by a prompt signal from the positron and a delayed neutron signal, which allow to decrease significantly the uncorrelated background. Other forms of background, in particular the cosmic correlated one, are managed using different technic. The use of two equal detectors at different baselines will allow to better control our systematic errors, in particular the ones associated with the reactor and with the reactor anomaly effect. The first detector (known as the 'far detector', 1050m from the reactors) is already in operation since April 2011 and the second one (known as the 'near detector', 400m from the reactor) is under construction. Thus, in this work we present the main aspects of this neutrino oscillation experiment and results update. (author)

T-odd momentum correlation in radiative {beta} decay

Energy Technology Data Exchange (ETDEWEB)

Gardner, Susan, E-mail: gardner@pa.uky.edu; He, Daheng [University of Kentucky, Department of Physics and Astronomy (United States)

2013-03-15

The triple-product correlations observable in ordinary neutron or nuclear beta decay are all naively T violating and can connect, through an assumption of CPT invariance, to constraints on sources of CP violation beyond the Standard Model. They are also spin dependent. In this context the study of radiative beta decay opens a new possibility, in that a triple-product correlation can be constructed from momenta alone. Consequently its measurement would constrain new spin-independent sources of CP violation. We will describe these in light of the size of the triple momentum correlation in the decay rate arising from electromagnetic final-state interactions in the Standard Model. Our expression for the corresponding T-odd asymmetry is exact in O({alpha}) up to terms of recoil order, and we evaluate it numerically under various kinematic conditions. We consider the pattern of the asymmetries in nuclear {beta} decays and show that the asymmetry can be suppressed in particular cases, facilitating searches for new sources of CP violation in such processes.

Beta-delayed neutron decay of $^{33}$Na

CERN Document Server

Radivojevic, Z; Caurier, E; Cederkäll, J; Courtin, S; Dessagne, P; Jokinen, A; Knipper, A; Le Scornet, G; Lyapin, V G; Miehé, C; Nowacki, F; Nummela, S; Oinonen, M; Poirier, E; Ramdhane, M; Trzaska, W H; Walter, G; Äystö, J

2002-01-01

Beta-delayed neutron decay of /sup 33/Na has been studied using the on-line mass separator ISOLDE. The delayed neutron spectra were measured by time-of-flight technique using fast scintillators. Two main neutron groups at 800(60) and 1020(80) keV were assigned to the /sup 33/Na decay, showing evidence for strong feeding of states at about 4 MeV in /sup 33/Mg. By simultaneous beta - gamma -n counting the delayed neutron emission probabilities P/sub 1n/ = 47(6)% and P /sub 2n/ = 13(3)% were determined. The half-life value for /sup 33 /Na, T/sub 1/2/ = 8.0(3) ms, was measured by three different techniques, one employing identifying gamma transitions and two employing beta and neutron counting. (21 refs).

Search for 0νββ-decay with gerda phase II

Science.gov (United States)

Majorovits, B.

2018-01-01

The Gerda experiment is designed to search for neutrinoless double beta decay of 76Ge. From data taken during Phase I of the experiment some knowledge on background contributions important for future experiments could be obtained: limits on the bulk contamination of HPGe with primordial uranium and thorium are presented and first evidence for observation of the decay of the meta-stable state of 77mGe due to neutron capture on 76Ge is discussed. In Phase II of the Gerda experiment 37 HPGe detectors enriched in the isotope 76Ge are deployed into the Gerda cryostat. From non-observation of a peak at 2039 keV a half-life limit on neutrinoless double beta decay of 76Ge of T1/2 > 5.3 . 1025 yr has been obtained. The background rate in the energy region of interest, after pulse shape discrimination and liquid argon veto cuts is in the range of a few Cts//ROI ton yr). This makes Gerda the first 0νββ-experiment that has a background so low that <1 counts are expected in the RoI within the anticipated life time of the experiment.

Search for the neutrinoless ββ decay in 76Ge with the GERDA experiment

International Nuclear Information System (INIS)

Cattadori, C.; Knapp, M.; Kröninger, K.; Liu, X.; Pandola, L.; Pullia, A.; Tomei, C.; Ur, C.; Zocca, F.

2011-01-01

The GERmanium Detector Array, GERDA, [Gerda Collaboration, Abt I et al., Proposal, a (http://www.mpi-hd.mpg.de/ge76/home.html)] is designed to search for neutrinoless double beta (0νββ)-decay of 76 Ge. The importance of such a search is emphasized by the evidence of a non-zero neutrino mass from flavour oscillation experiments and by the recent claim [Klapdor-Kleingrothaus H V et al., Phys. Lett. B 586, 198 (2004)] based on data of the Heidelberg-Moscow experiment. GERDA will be installed in the Hall A of the Gran Sasso underground Laboratory (LNGS), Italy. The construction of GERDA will start in 2006.

Search for two-neutrino double-β decay of 96Zr to excited states of 96Mo

Science.gov (United States)

Finch, S. W.; Tornow, W.

2015-10-01

Background: Double-β decay is a rare second-order nuclear decay. The importance of this decay stems from the possibility of neutrinoless double-β decay and its applications to neutrino physics. Purpose: A search was conducted for the 2 ν β β decay of 96Zr to excited final states of the daughter nucleus, 96Mo. Measurements of this decay are important to test nuclear matrix element calculations, which are necessary to extract the neutrino mass from a measurement of the neutrinoless double-β decay half-life. Method: Two coaxial high-purity germanium detectors were used in coincidence to detect γ rays produced by the daughter nucleus as it de-excited to the ground state. The experiment was carried out at the Kimballton Underground Research Facility and produced 685.7 d of data with a 17.91 g enriched sample. Results: No counts were seen above background. For the decay to the first excited 0+ state, a limit of T1 /2>3.1 ×1020 yr was produced. Limits to higher excited states are also reported. Conclusion: The new limits on double-β decay are an improvement over previous experiments by a factor of 2 to 5 for the various excited states. The nuclear matrix element for the double-β decay to the first excited 0+ state is found to be <0.13 .

Scintillating bolometers: A promising tool for rare decays search

Energy Technology Data Exchange (ETDEWEB)

Pattavina, L., E-mail: luca.pattavina@mib.infn.it

2013-12-21

The idea of using a scintillating bolometer was first suggested for solar neutrino experiments in 1989. After many years of developments, now we are able to exploit this experimental technique, based on the calorimetric approach with cryogenic particle detectors, to investigate rare events such as Neutrinoless Double Beta Decay and interaction of Dark Matter candidates. The possibility to have high resolution detectors in which a very large part of the natural background can be discriminated with respect to the weak expected signal is very appealing. The goal to distinguish the different types of interactions in the detector can be achieved by means of scintillating bolometer. The simultaneous read-out of the heat and scintillation signals made with two independent bolometers enable this precious feature leading to possible background free experiment. In the frame of the LUCIFER project we report on how exploiting this technique to investigate Double Beta Decay for different isotope candidates. Moreover we demonstrate how scintillating bolometers are suited for investigating other rare events such as α decays of long living isotopes of lead and bismuth.

Surface Alpha Interactions in P-Type Point-Contact HPGe Detectors: Maximizing Sensitivity of 76Ge Neutrinoless Double-Beta Decay Searches

Science.gov (United States)

Gruszko, Julieta

Though the existence of neutrino oscillations proves that neutrinos must have non-zero mass, Beyond-the-Standard-Model physics is needed to explain the origins of that mass. One intriguing possibility is that neutrinos are Majorana particles, i.e., they are their own anti-particles. Such a mechanism could naturally explain the observed smallness of the neutrino masses, and would have consequences that go far beyond neutrino physics, with implications for Grand Unification and leptogenesis. If neutrinos are Majorana particles, they could undergo neutrinoless double-beta decay (0nBB), a hypothesized rare decay in which two antineutrinos annihilate one another. This process, if it exists, would be exceedingly rare, with a half-life over 1E25 years. Therefore, searching for it requires experiments with extremely low background rates. One promising technique in the search for 0nBB is the use of P-type point-contact (P-PC) high-purity Germanium (HPGe) detectors enriched in 76Ge, operated in large low-background arrays. This approach is used, with some key differences, by the MAJORANA and GERDA Collaborations. A problematic background in such large granular detector arrays is posed by alpha particles incident on the surfaces of the detectors, often caused by 222Rn contamination of parts or of the detectors themselves. In the MAJORANA DEMONSTRATOR, events have been observed that are consistent with energy-degraded alphas originating near the passivated surface of the detectors, leading to a potential background contribution in the region-of-interest for neutrinoless double-beta decay. However, it is also observed that when energy deposition occurs very close to the passivated surface, high charge trapping occurs along with subsequent slow charge re-release. This leads to both a reduced prompt signal and a measurable change in slope of the tail of a recorded pulse. Here we discuss the characteristics of these events and the development of a filter that can identify the

$\\beta$-asymmetry measurements in nuclear $\\beta$-decay as a probe for non-standard model physics

CERN Multimedia

Roccia, S

2002-01-01

We propose to perform a series of measurements of the $\\beta$-asymmetry parameter in the decay of selected nuclei, in order to investigate the presence of possible time reversal invariant tensor contributions to the weak interaction. The measurements have the potential to improve by a factor of about four on the present limits for such non-standard model contributions in nuclear $\\beta$-decay.

Improving the physics impact of next-generation ⁷⁶Ge neutrinoless double-beta decay experiments

Energy Technology Data Exchange (ETDEWEB)

Hossbach, Todd W. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2009-01-01

It was shown that segmentation and pulse-shape discrimination can improve the discovery sensitivity of a next-gen 0vBB-decay experiment by 90%. - However, when practical aspects are considered (such as instrumenting each segment with front-end electronics), the discovery sensitivity is decreased by 19%. - This has extremely important consequences to proposed next-gen experiments since the two active collaborations have strongly advocated the use of segmented detectors for all or part of the experiment. - New germanium detector technology, currently under development, has demonstrated excellent multi-site background rejection capabilities without the complexity of segmentation or complicated PSD algorithms. - The physically-segmented p-type germanium detector technology has proven to be a useful and practical tool in modern nuclear physics. The PSEG technology deserves further development as it has the potential for use in a variety of applications.

Progress report on the Los Alamos tritium beta decay experiment

International Nuclear Information System (INIS)

Wilkerson, J.F.; Bowles, T.J.; Knapp, D.A.; Robertson, R.G.H.; Wark, D.L.

1988-01-01

Measurements near the endpoint of the tritium beta-decay spectrum using a gaseous molecular tritium source yield an essentially model-independent upper limit of 27 eV on the /ovr ν//sub e/ mass at the 95% confidence level. Since demonstrating from this initial measurement the successful operation of a gaseous source based system, most of our effort has been concentrated towards the upgrade and optimization of the experimental apparatus. The emphasis of this work has been to eliminate or further reduce effects that generate systematic errors. Based on realistic projections from our initial measurement, an ultimate sensitivity to neutrino mass of 10 eV is expected. 12 refs., 1 fig

Limit on neutrinoless ββ decay of 136Xe from the first phase of KamLAND-Zen and comparison with the positive claim in 76Ge

NARCIS (Netherlands)

Gando, A.; Gando, Y.; Hanakago, H.; Ikeda, H.; Inoue, K.; Ishidoshiro, K.; Kato, R.; Koga, M.; Matsuda, S.; Mitsui, T.; Motoki, D.; Nakada, T.; Nakamura, K.; Obata, A.; Oki, A.; Ono, Y.; Otani, M.; 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.; Freedman, S.J.; Fujikawa, B.K.; Han, K.; O’Donnell, T.; Berger, B.E.; Efremenko, Y.; Karwowski, H.J.; Markoff, D.M.; Tornow, W.; Detwiler, J.A.; Enomoto, S.; Decowski, M.P.

2013-01-01

We present results from the first phase of the KamLAND-Zen double-beta decay experiment, corresponding to an exposure of 89.5 kg yr of Xe136. We obtain a lower limit for the neutrinoless double-beta decay half-life of T0ν1/2>1.9×1025  yr at 90% C.L. The combined results from KamLAND-Zen and EXO-200

Microscopic beta and gamma data for decay-heat needs

International Nuclear Information System (INIS)

Dickens, J.K.

1983-01-01

Microscopic beta and gamma data for decay-heat needs are defined as absolute-intensity spectral distributions of beta and gamma rays following radioactive decay of radionuclides created by, or following, the fission process. Four well-known evaluated data files, namely the US ENDF/B-V, the UK UKFPDD-2, the French BDN (for fission products), and the Japanese JNDC Nuclear Data Library, are reviewed. Comments regarding the analyses of experimental data (particularly gamma-ray data) are given; the need for complete beta-ray spectral measurements is emphasized. Suggestions on goals for near-term future experimental measurements are presented. 34 references

Nuclear beta decay far from stability and astrophysics

International Nuclear Information System (INIS)

Klapdor, H.V.

1988-01-01

Beta decay data of nuclei far from stability are one of the most important nuclear physics input for the understanding of the element systhesis in the universe and determination of the age of the universe from cosmochronometers and by the latter have implications also for cosmology. The present status of theoretical predictions of beta decay far from stability will be reviewed and the impact on the above astrophysical questions will be outlined. First results of second generation microscopic calculations of β F half lives, which are at present in progress, will be presented. (orig.)

Beta decay heat following U-235, U-238 and Pu-239 neutron fission

Science.gov (United States)

Li, Shengjie

1997-09-01

This is an experimental study of beta-particle decay heat from 235U, 239Pu and 238U aggregate fission products over delay times 0.4-40,000 seconds. The experimental results below 2s for 235U and 239Pu, and below 20s for 238U, are the first such results reported. The experiments were conducted at the UMASS Lowell 5.5-MV Van de Graaff accelerator and 1-MW swimming-pool research reactor. Thermalized neutrons from the 7Li(p,n)7Be reaction induced fission in 238U and 239Pu, and fast neutrons produced in the reactor initiated fission in 238U. A helium-jet/tape-transport system rapidly transferred fission fragments from a fission chamber to a low background counting area. Delay times after fission were selected by varying the tape speed or the position of the spray point relative to the beta spectrometer that employed a thin-scintillator-disk gating technique to separate beta-particles from accompanying gamma-rays. Beta and gamma sources were both used in energy calibration. Based on low-energy(energies 0-10 MeV. Measured beta spectra were unfolded for their energy distributions by the program FERD, and then compared to other measurements and summation calculations based on ENDF/B-VI fission-product data performed on the LANL Cray computer. Measurements of the beta activity as a function of decay time furnished a relative normalization. Results for the beta decay heat are presented and compared with other experimental data and the summation calculations.

Excited state transitions in 2νββ decays of {sup 76}Ge from phase I of the GERDA experiment

Energy Technology Data Exchange (ETDEWEB)

Wester, Thomas [IKTP, TU Dresden (Germany); Collaboration: GERDA-Collaboration

2015-07-01

The Germanium Detector Array GERDA is an experiment searching for the neutrinoless double beta decay in {sup 76}Ge. The observation of such a decay would prove the Majorana character of the neutrino and could provide a hint about the neutrino mass and possibly identify the mass hierarchy scheme. The half life of the neutrino accompanied double beta decay (2νββ) of {sup 76}Ge has been measured by GERDA Phase I with unprecedented precision. The observed spectrum comes mostly from the transition from the 0{sup +} ground state of {sup 76}Ge to the 0{sup +} ground state of {sup 76}Se. However, phase space suppressed 2νββ transitions to excited states of {sup 76}Se exist as well. At current state, the predicted half lives for such decays vary by several orders of magnitude, due to the large uncertainties in the nuclear matrix elements and the available nuclear models. An observation would therefore help to constrain model parameters and decrease those uncertainties. This study investigates the 2νββ decay of {sup 76}Ge into various excited states of {sup 76}Se using the data from GERDA Phase I. An event counting method is performed based on coincident events between two germanium detectors. Several analysis parameters are optimized with the help of Monte Carlo simulations to maximize the sensitivity. The presentation discusses the procedure and results of this analysis.

Background-free search for neutrinoless double-β decay of 76Ge with GERDA

Science.gov (United States)

Agostini, M.; Allardt, M.; Bakalyarov, A. M.; Balata, M.; Barabanov, I.; Baudis, L.; Bauer, C.; Bellotti, E.; Belogurov, S.; Belyaev, S. T.; Benato, G.; Bettini, A.; Bezrukov, L.; Bode, T.; Borowicz, D.; Brudanin, V.; Brugnera, R.; Caldwell, A.; Cattadori, C.; Chernogorov, A.; D'Andrea, V.; Demidova, E. V.; di Marco, N.; di Vacri, A.; Domula, A.; Doroshkevich, E.; Egorov, V.; Falkenstein, R.; Fedorova, O.; Freund, K.; Frodyma, N.; Gangapshev, A.; Garfagnini, A.; Gooch, C.; Grabmayr, P.; Gurentsov, V.; Gusev, K.; Hakenmüller, J.; Hegai, A.; Heisel, M.; Hemmer, S.; Hofmann, W.; Hult, M.; Inzhechik, L. V.; Janicskó Csáthy, J.; Jochum, J.; Junker, M.; Kazalov, V.; Kihm, T.; Kirpichnikov, I. V.; Kirsch, A.; Kish, A.; Klimenko, A.; Kneißl, R.; 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.; Macolino, C.; Majorovits, B.; Maneschg, W.; Medinaceli, E.; Miloradovic, M.; Mingazheva, R.; Misiaszek, M.; Moseev, P.; Nemchenok, I.; Palioselitis, D.; Panas, K.; Pandola, L.; Pelczar, K.; Pullia, A.; Riboldi, S.; Rumyantseva, N.; Sada, C.; Salamida, F.; Salathe, M.; Schmitt, C.; Schneider, B.; Schönert, S.; Schreiner, J.; Schulz, O.; Schütz, A.-K.; Schwingenheuer, B.; Selivanenko, O.; Shevchik, E.; Shirchenko, M.; Simgen, H.; Smolnikov, A.; Stanco, L.; Vanhoefer, L.; Vasenko, A. A.; Veresnikova, A.; von Sturm, K.; Wagner, V.; Walter, M.; Wegmann, A.; Wester, T.; Wiesinger, C.; Wojcik, M.; Yanovich, E.; Zhitnikov, I.; Zhukov, S. V.; Zinatulina, D.; Zuber, K.; Zuzel, G.; GERDA Collaboration

2017-04-01

Many extensions of the Standard Model of particle physics explain the dominance of matter over antimatter in our Universe by neutrinos being their own antiparticles. This would imply the existence of neutrinoless double-β decay, which is an extremely rare lepton-number-violating radioactive decay process whose detection requires the utmost background suppression. Among the programmes that aim to detect this decay, the GERDA Collaboration is searching for neutrinoless double-β decay of 76Ge by operating bare detectors, made of germanium with an enriched 76Ge fraction, in liquid argon. After having completed Phase I of data taking, we have recently launched Phase II. Here we report that in GERDA Phase II we have achieved a background level of approximately 10-3 counts keV-1 kg-1 yr-1. This implies that the experiment is background-free, even when increasing the exposure up to design level. This is achieved by use of an active veto system, superior germanium detector energy resolution and improved background recognition of our new detectors. No signal of neutrinoless double-β decay was found when Phase I and Phase II data were combined, and we deduce a lower-limit half-life of 5.3 × 1025 years at the 90 per cent confidence level. Our half-life sensitivity of 4.0 × 1025 years is competitive with the best experiments that use a substantially larger isotope mass. The potential of an essentially background-free search for neutrinoless double-β decay will facilitate a larger germanium experiment with sensitivity levels that will bring us closer to clarifying whether neutrinos are their own antiparticles.

Latest results from the Double Chooz experiment

Energy Technology Data Exchange (ETDEWEB)

Goeger-Neff, Marianne [Physik Department E15, Technische Universitaet Muenchen (Germany); Collaboration: Double Chooz-Collaboration

2016-07-01

Double Chooz aims at a precise measurement of the neutrino mixing angle θ{sub 13} through the disappearance of reactor electron antineutrinos. The experiment relies on the measurement of neutrino flux and spectrum with two identical detectors at 400 m and 1000 m from the reactor cores of two nuclear power reactors. anti ν{sub e} are detected by inverse beta decay on free protons in 8.3 tons of Gd-loaded liquid scintillator, providing a unique delayed coincidence signature. Double Chooz has been running since 2011 with the far detector only, providing the first indication for non-zero θ{sub 13} with reactor antineutrinos. With a rate+shape analysis of 467.90 live days from 2011-2013 we obtain a value of sin {sup 2} 2 θ{sub 13}=0.090{sup +0.032}{sub -0.029}. Data taking with the near detector has started beginning of 2015, allowing a significant reduction of both reactor and detector related systematic uncertainties. The talk reviews the most recent results obtained with the far detector only and discuss first data from the near detector.

Neutrinoless double β decay and low scale leptogenesis

Energy Technology Data Exchange (ETDEWEB)

Drewes, Marco, E-mail: marco.drewes@tum.de [Physik Department T70, Technische Universität München, James Franck Straße 1, D-85748 Garching (Germany); Eijima, Shintaro [Institute of Physics, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne (Switzerland)

2016-12-10

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 β 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 β decay experiments have already started to rule out part of the leptogenesis parameter space that is not constrained by any other experiment, and the lepton number violation that is responsible for the origin of baryonic matter in the universe may be observed in the near future.

Status of the Majorana Demonstrator experiment

Science.gov (United States)

Martin, R. D.; Abgrall, N.; Aguayo, E.; Avignone, F. T., III; Barabash, A. S.; Bertrand, F. E.; Boswell, M.; Brudanin, V.; Busch, M.; Caldwell, A. S.; Chan, Y.-D.; Christofferson, C. D.; Combs, D. C.; Detwiler, J. A.; Doe, P. J.; Efremenko, Yu.; Egorov, V.; Ejiri, H.; Elliott, S. R.; Esterline, J.; Fast, J. E.; Finnerty, P.; Fraenkle, F. M.; Galindo-Uribarri, A.; Giovanetti, G. K.; Goett, J.; Green, M. P.; Gruszko, J.; Guiseppe, V. E.; Gusev, K.; Hallin, A. L.; Hazama, R.; Hegai, A.; Henning, R.; Hoppe, E. W.; Howard, S.; Howe, M. A.; Keeter, K. J.; Kidd, M. F.; Kochetov, O.; Konovalov, S. I.; Kouzes, R. T.; LaFerriere, B. D.; Leon, J.; Leviner, L. E.; Loach, J. C.; MacMullin, J.; MacMullin, S.; Mertens, S.; Mizouni, L.; Nomachi, M.; Orrell, J. L.; O'Shaughnessy, C.; Overman, N. R.; Phillips, D. G., II; Poon, A. W. P.; Pushkin, K.; Radford, D. C.; Rielage, K.; Robertson, R. G. H.; Romero-Romero, E.; Ronquest, M. C.; Schubert, A. G.; Shanks, B.; Shima, T.; Shirchenko, M.; Snavely, K. J.; Snyder, N.; Soin, A.; Suriano, A. M.; Thompson, J.; Timkin, V.; Tornow, W.; Varner, R. L.; Vasilyev, S.; Vetter, K.; Vorren, K.; White, B. R.; Wilkerson, J. F.; Xu, W.; Yakushev, E.; Young, A. R.; Yu, C.-H.; Yumatov, V.

2014-06-01

The Majorana Demonstrator neutrinoless double beta-decay experiment is currently under construction at the Sanford Underground Research Facility in South Dakota, USA. An overview and status of the experiment are given.

Results of a search for the neutrinoless double beta decay of 76Ge to the first excited state of 76Se

International Nuclear Information System (INIS)

Morales, A.; Morales, J.; Nunez-Lagos, R.; Puimedon, J.; Villar, J.A.; Larrea, A.

1988-01-01

A search for the neutrinoless double beta decay of 76 Ge to the first excited state E=559.1 KeV of 76 Se has been carried out in the Frejus tunnel using a coincidence technique between Ge and NaI detectors. No peak has been observed in the electron energy spectrum at the value of 1482 KeV. That implies a half-life lower limit of 6 x 10 22 years. However the experimental data display a coincidence, at the level of 2.5 σ, between an energy deposition of 1483.7 ± 0.5 KeV in the Ge detector and 558 ± 15 KeV in the NaI detector. The main features of such a coincidence effect are analysed and, in spite of its small statistical significance, its possible interpretation is discussed

Beta decay to the second 2+ excited state of 122Te

International Nuclear Information System (INIS)

Hayashi, Takeo; Yamada, Shigeru

1976-01-01

The first-forbidden beta transition in Sb-122 was studied by the angular correlation experiment and the beta-spectra. The special precautions were paid for counting the beta particles having energy lower than 750 keV in the beta-gamma angular correlation measurement. The sources of Sb-122 were obtained by irradiating enriched Sb-121 in the Kyoto University reactor. The reduced beta coefficient R(E) was obtained from the angular correlation function. The beta spectrum measurement was performed with a sector type double focusing beta-ray spectrometer. The R(E) values for the beta transitions were analyzed by using the simplex method as used by Manthuruthil and Poirier to compare the angular correlation data with the exact formula given by Morita and Morita. Sets of the nuclear matrix parameters thus obtained show that the condition for the cancellation effect is satisfied in the beta transition. (Kato, T.)

Limits on Tensor Coupling from Neutron $\\beta$-Decay

OpenAIRE

Pattie Jr, Robert W.; Hickerson, Kevin P.; Young, Albert R.

2013-01-01

Limits on the tensor couplings generating a Fierz interference term, b, in mixed Gamow-Teller Fermi decays can be derived by combining data from measurements of angular correlation parameters in neutron decay, the neutron lifetime, and $G_{\\text{V}}=G_{\\text{F}} V_{ud}$ as extracted from measurements of the $\\mathcal{F}t$ values from the $0^{+} \\to 0^{+}$ superallowed decays dataset. These limits are derived by comparing the neutron $\\beta$-decay rate as predicted in the standard model with t...

Measurement of the 2νββ decay of 100Mo to the excited 01+ state in the NEMO3 experiment

International Nuclear Information System (INIS)

Vala, L.

2003-09-01

The NEMO3 detector was designed for the study of double beta decay and in particular to search for the neutrinoless double beta decay process (0νββ). The intended sensitivity in terms of a half-life limit for the 0νββ decay is of the order of 10 25 y which corresponds to an effective neutrino mass m ν on the level of (0.3 - 0.1) eV. The 0νββ process is today the most promising test of the Majorana nature of the neutrino. The detector was constructed in the Modane Underground Laboratory (LSM) in France by an international collaboration including France, Russia, the Czech Republic, the USA, the UK, Finland, and Japan. The experiment has been taking data since May 2002. The quantity of 100 Mo in the detector (7 kg) allows an efficient measurement of the two-neutrino double beta decay (2νββ) of 100 Mo to the excited 0 1 + state (eeNγ channel). Monte-Carlo simulations of the effect and of all the relative sources of background have been produced in order to define a set of appropriate selection criteria. Both Monte-Carlo simulations and special runs with sources of 208 Tl and 214 Bi showed that the only significant background in the eeNγ channel comes from radon that penetrated inside the wire chamber of NEMO3. The experimental data acquired from May 2002 to May 2003 have been analysed in order to determine the signal from the 2νββ decay of 100 Mo to the excited 0 1 + state and the corresponding background level. The physical result, which was obtained at the level of four standard deviations, is given in the form of an interval of half-life values at 95% confidence level: [5.84*10 20 , 2.26*10 21 ] y for method A and [5.83*10 20 , 1.71*10 21 ] y for method B. (author)

Measurement of the form factor ratio g1/f1 in LAMBDA beta decay

International Nuclear Information System (INIS)

Innes, W.R.

1974-01-01

The beta decay of 306 polarized lambdas was observed. The lambdas, which had a mean polarization of 70 percent, were produced by a 1.06 GeV/c π minus beam incident on a CH 2 target. The lambda decay particle trajectories were measured with a solenoidal magnetic spectrometer utilizing spark chambers with magnetostrictive readout. The beta decays were differentiated from other decay modes with an isobutane threshold Cherenkov counter. Using only information which depended upon the polarization, g 1 /f 1 was found to be 0.44- 0 . 13 +0 . 20 . Using only information independent of the polarization, g 1 /f 1 was found to be 0.62- 0 . 13 +0 . 17 . Combining all information yielded a value for g 1 /f 1 of 0.56- 0 . 11 +0 . 13 . Although these results taken by themselves are consistent with the Cabbibo theory prediction of 0.69, when combined with previous experiments there is a possibly significant discrepancy in the polarization dependent results. (U.S.)

Status report on the International Germanium Experiment

International Nuclear Information System (INIS)

Brodzinski, R.L.; Hensley, W.K.; Miley, H.S.; Reeves, J.H.; Avignone, F.T.; Collar, J.I.; Guerard, C.K.; Courant, H.; Ruddick, K.; Kirpichnikov, I.V.; Starostin, A.S.; Osetrov, S.B.; Pomansky, A.A.; Smolnikov, A.A.; Vasiliev, S.I.

1992-06-01

Phase II detector fabrication for the International Germanium Experiment is awaiting resolution of technical details observed during Phase I. Measurements of fiducial volume, configuration of the tansistor-reset preamplifier stage, and sources of background are discussed. Cosmogenic 7 Be is measured in germanium. Radium contamination in electroformed copper reported. The 2ν double- beta decay half-life of 76 Ge measured with a Phase I detector is in reasonable agreement with previously reported values. No events are observed in the vicinity of the Oν double-beta decay energy

Nuclear beta decay and the weak interaction

International Nuclear Information System (INIS)

Kean, D.C.

1975-11-01

Short notes are presented on various aspects of nuclear beta decay and weak interactions including: super-allowed transitions, parity violation, interaction strengths, coupling constants, and the current-current formalism of weak interaction. (R.L.)

Addendum to: ''The SNO solar neutrino data, neutrinoless double beta-decay and neutrino mass spectrum'' [Phys. Lett. B 544 (2002) 239

International Nuclear Information System (INIS)

Pascoli, S.; Petcov, S.T.

2004-01-01

We update our earlier study [Phys. Lett. B 544 (2002) 239], which was inspired by the 2002 SNO data, on the implications of the results of the solar neutrino experiments for the predictions of the effective Majorana mass in neutrinoless double beta-decay, vertical bar vertical bar. We obtain predictions for vertical bar vertical bar using the values of the neutrino oscillation parameters, obtained in the analyzes of the presently available solar neutrino data, including the just published data from the salt phase of the SNO experiment, the atmospheric neutrino and CHOOZ data and the first data from the KamLAND experiment. The main conclusion reached in the previous study [Phys. Lett. B 544 (2002) 239] of the existence of significant lower bounds on vertical bar vertical bar in the cases of neutrino mass spectrum of inverted hierarchical (IH) and quasi-degenerate (QD) type is strongly reinforced by fact that combined solar neutrino data (i) exclude the possibility of cos2θ o =0 at more than 5 s.d., (ii) determine as a best fit value cos2θ o =0.40, and (iii) imply at 95% C.L. that cos2θ o ∼>0.22, θ o being the solar neutrino mixing angle. For the IH and QD spectra we get using, e.g., the 90% C.L. allowed ranges of values of the oscillation parameters, vertical bar vertical bar ∼>0.010 eV and vertical bar vertical bar ∼>0.043 eV, respectively. We also comment on the possibility to get information on the neutrino mass spectrum and on the CP-violation in the lepton sector due to Majorana CP-violating phases

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

Energy Technology Data Exchange (ETDEWEB)

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 des rapports

Gross theory of beta-decay and half-lives of short-lived nuclei

International Nuclear Information System (INIS)

Yamada, Masami; Kondo, Norikatsu.

1976-01-01

The gross theory of beta-decay has been developed, and this theory offers the means of calculating directly the function of beta-decay intensity, then half-lives, complex beta spectra and so on are estimated from it. This paper presents the more refined theory by introducing the shell effect. The shell effect is considered in the intensity function. The half-lives in the electron decay of In with spin of 9/2 + , the positron decay of Bi, Po, At and Rn, and the decay of odd-odd nuclei were estimated. The introduction of the shell effect shows better agreement between the theory and the experimental data. The inequality relations of intensity functions and half-lives of two adjacent nuclei were obtained. When the spins and parities of two nuclei are same, the inequality relations hold especially good. (Kato, T.)

Neutrinoless double β decay and low scale leptogenesis

Directory of Open Access Journals (Sweden)

Marco Drewes

2016-12-01

Full Text Available 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 β 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 β decay experiments have already started to rule out part of the leptogenesis parameter space that is not constrained by any other experiment, and the lepton number violation that is responsible for the origin of baryonic matter in the universe may be observed in the near future.

Absolute measurement of the $\\beta\\alpha$ decay of $^{16}$N

CERN Multimedia

We propose to study the $\\beta$-decay of $^{16}$N at ISOLDE with the aim of determining the branching ratio for $\\beta\\alpha$ decay on an absolute scale. There are indications that the previously measured branching ratio is in error by an amount significantly larger than the quoted uncertainty. This limits the precision with which the S-factor of the astrophysically important $^{12}$C($\\alpha, \\gamma)^{16}$O reaction can be determined.

The use of cosmic-ray muons in the energy calibration of the Beta-decay Paul Trap silicon-detector array

Energy Technology Data Exchange (ETDEWEB)

Hirsh, T. Y.; Perez Galvan, A.; Burkey, M.; Aprahamian, A.; Buchinger, F.; Caldwell, S.; Clark, J. A.; Gallant, A.; Heckmaier, E.; Levand, A. F.; Savard, G.

2018-04-01

This article presents an approach to calibrate the energy response of double-sided silicon strip detectors (DSSDs) for low-energy nuclear-science experiments by utilizing cosmic-ray muons. For the 1-mm-thick detectors used with the Beta-decay Paul Trap, the minimum-ionizing peak from these muons provides a stable and time-independent in situ calibration point at around 300 keV, which supplements the calibration data obtained above 3 MeV from sources. The muon-data calibration is achieved by comparing experimental spectra with detailed Monte Carlo simulations performed using GEANT4 and CRY codes. This additional information constrains the calibration at lower energies, resulting in improvements in quality and accuracy.

Liquid argon as active shielding and coolant for bare germanium detectors. A novel background suppression method for the GERDA 0{nu}{beta}{beta} experiment

Energy Technology Data Exchange (ETDEWEB)

Peiffer, J.P.

2007-07-25

Two of the most important open questions in particle physics are whether neutrinos are their own anti-particles (Majorana particles) as required by most extensions of the StandardModel and the absolute values of the neutrino masses. The neutrinoless double beta (0{nu}{beta}{beta}) decay, which can be investigated using {sup 76}Ge (a double beta isotope), is the most sensitive probe for these properties. There is a claim for an evidence for the 0{nu}{beta}{beta} decay in the Heidelberg-Moscow (HdM) {sup 76}Ge experiment by a part of the HdM collaboration. The new {sup 76}Ge experiment Gerda aims to check this claim within one year with 15 kg.y of statistics in Phase I at a background level of {<=}10{sup -2} events/(kg.keV.y) and to go to higher sensitivity with 100 kg.y of statistics in Phase II at a background level of {<=}10{sup -3} events/(kg.keV.y). In Gerda bare germanium semiconductor detectors (enriched in {sup 76}Ge) will be operated in liquid argon (LAr). LAr serves as cryogenic coolant and as high purity shielding against external background. To reach the background level for Phase II, new methods are required to suppress the cosmogenic background of the diodes. The background from cosmogenically produced {sup 60}Co is expected to be {proportional_to}2.5.10{sup -3} events/(kg.keV.y). LAr scintillates in UV ({lambda}=128 nm) and a novel concept is to use this scintillation light as anti-coincidence signal for background suppression. In this work the efficiency of such a LAr scintillation veto was investigated for the first time. In a setup with 19 kg active LAr mass a suppression of a factor 3 has been achieved for {sup 60}Co and a factor 17 for {sup 232}Th around Q{sub {beta}}{sub {beta}} = 2039 keV. This suppression will further increase for a one ton active volume (factor O(100) for {sup 232}Th and {sup 60}Co). LAr scintillation can also be used as a powerful tool for background diagnostics. For this purpose a new, very stable and robust wavelength

Large-scale calculations of the beta-decay rates and r-process nucleosynthesis

Energy Technology Data Exchange (ETDEWEB)

Borzov, I N; Goriely, S [Inst. d` Astronomie et d` Astrophysique, Univ. Libre de Bruxelles, Campus Plaine, Bruxelles (Belgium); Pearson, J M [Inst. d` Astronomie et d` Astrophysique, Univ. Libre de Bruxelles, Campus Plaine, Bruxelles (Belgium); [Lab. de Physique Nucleaire, Univ. de Montreal, Montreal (Canada)

1998-06-01

An approximation to a self-consistent model of the ground state and {beta}-decay properties of neutron-rich nuclei is outlined. The structure of the {beta}-strength functions in stable and short-lived nuclei is discussed. The results of large-scale calculations of the {beta}-decay rates for spherical and slightly deformed nuclides of relevance to the r-process are analysed and compared with the results of existing global calculations and recent experimental data. (orig.)

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

International Nuclear Information System (INIS)

Piquemal, F.

1994-05-01

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 10 25 years for 100 Mo). 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 214 Bi 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)

Long-range contributions to double beta decay revisited

Energy Technology Data Exchange (ETDEWEB)

Helo, J.C. [Universidad Técnica Federico Santa María, Centro-Científico-Tecnológico de Valparaíso,Casilla 110-V, Valparaíso (Chile); Departamento de Física, Facultad de Ciencias, Universidad de La Serena, Avenida Cisternas 1200, La Serena (Chile); Hirsch, M. [HEP Group, Instituto de Física Corpuscular,C.S.I.C./Universitat de València Edificio Institutos de Investigacion,Parc Cientific de Paterna, Apartado 22085, E-46071 València (Spain); Ota, T. [Department of Physics, Saitama University,Shimo-Okubo 255, 338-8570 Saitama-Sakura (Japan)

2016-06-01

We discuss the systematic decomposition of all dimension-7 (d=7) lepton number violating operators. These d=7 operators produce momentum enhanced contributions to the long-range part of the 0νββ decay amplitude and thus are severely constrained by existing half-live limits. In our list of possible models one can find contributions to the long-range amplitude discussed previously in the literature, such as the left-right symmetric model or scalar leptoquarks, as well as some new models not considered before. The d=7 operators generate Majorana neutrino mass terms either at tree-level, 1-loop or 2-loop level. We systematically compare constraints derived from the mass mechanism to those derived from the long-range 0νββ decay amplitude and classify our list of models accordingly. We also study one particular example decomposition, which produces neutrino masses at 2-loop level, can fit oscillation data and yields a large contribution to the long-range 0νββ decay amplitude, in some detail.

Probing flavor models with {sup 76}Ge-based experiments on neutrinoless double-β decay

Energy Technology Data Exchange (ETDEWEB)

Agostini, Matteo [Technische Universitaet Muenchen, Physik Department and Excellence Cluster Universe, Munich (Germany); Gran Sasso Science Institute (INFN), L' Aquila (Italy); Merle, Alexander [Max-Planck-Institut fuer Physik (Werner-Heisenberg-Institut), Munich (Germany); Zuber, Kai [Technische Universitaet Dresden, Institute for Nuclear and Particle Physics, Dresden (Germany)

2016-04-15

The physics impact of a staged approach for double-β decay experiments based on {sup 76}Ge 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 {sup 76}Ge 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 achieve valuable physics results as early as possible. (orig.)

Time reversal in polarized neutron decay: the emiT experiment

CERN Document Server

Jones, G L; Anaya, J M; Bowles, T J; Chupp, T E; Coulter, K P; Dewey, M S; Freedman, S J; Fujikawa, B K; García, A; Greene, G L; Hwang, S R; Lising, L J; Mumm, H P; Nico, J S; Robertson, R G H; Steiger, T D; Teasdale, W A; Thompson, A K; Wasserman, E G; Wietfeldt, F E; Wilkerson, J F

2000-01-01

The standard electro-weak model predicts negligible violation of time-reversal invariance in light quark processes. We report on an experimental test of time-reversal invariance in the beta decay of polarized neutrons as a search for physics beyond the standard model. The emiT collaboration has measured the time-reversal-violating triple-correlation in neutron beta decay between the neutron spin, electron momentum, and neutrino momentum often referred to as the D coefficient. The first run of the experiment produced 14 million events which are currently being analyzed. However, a second run with improved detectors should provide greater statistical precision and reduced systematic uncertainties.

Neutrino mass, the right-handed interaction and the double beta decay, 1

International Nuclear Information System (INIS)

Doi, Masaru; Kotani, Tsuneyuki; Nishiura, Hiroyuki; Okuda, Kazuko; Takasugi, Eiichi.

1981-01-01

In order to shed light on the important question whether neutrinos are Dirac or Majorana particles, the double β decay is investigated within a general form of weak interaction Hamiltonian. The systematic study is made on the 0 + → J + nuclear transitions for the two-neutrino and neutrinoless modes both in the two-nucleon- and N*-mechanism. It is shown that for the neutrinoless mode, only the 0 + → 0 + transition in the two-nucleon mechanism is allowed if there is no right-handed interaction. When the right-handed interaction gives a sizable contribution, the role of the 0 + → 2 + transition becomes as important as the 0 + → 0 + transition. The comparison of our results with the previous ones is also presented. (author)

Developments for the 6He beta - nu angular correlation experiment

Science.gov (United States)

Zumwalt, David W.

This thesis describes developments toward the measurement of the angular correlation between the beta and the antineutrino in the beta decay of 6He. This decay is a pure Gamow-Teller decay which is described in the Standard Model as a purely axial vector weak interaction. The angular correlation is characterized by the parameter abetanu = -1/3 in the Standard Model. Any deviation from this value would be evidence for tensor components in the weak interaction and would constitute new physics. A new method will be used to measure the parameter a betanu from 6He decays, featuring a magneto-optical trap that will measure the beta particle in coincidence with the recoiling 6Li daughter ion. This neutral atom trapping scheme provides cold, tightly confined atoms which will reduce systematic uncertainties related to the initial position of the decay. By knowing the initial position of the decay and measuring the time of flight of the recoiling 6Li daughter ion in coincidence with the beta, the angular correlation between the beta and the antineutrino can be deduced. We aim to measure a betanu first to the level of 1%, and eventually to the 0.1% level, which would represent an order of magnitude improvement in precision over past experiments. Towards this goal, we have designed, built, and successfully tested a liquid lithium target to provide >2×10. {10} 6He atoms/sto a low-background environment, which is the most intense source of 6He presently available. This allowed for an additional measurement of the 6He half-life (806.89 +/- 0.11stat +0.23-0.19syst ms) to be made with unprecedented precision, resolving discrepancies in past measurements. We have also tested our trapping and detection apparatus and have begun to record preliminary coincidence events.

Study of the deuteron emission in the $\\beta$-decay of $^{6}$He

CERN Multimedia

Karny, M; Tengblad, O; Riisager, K; Perkowski, J; Garcia borge, M J; Raabe, R; Kowalska, M; Fynbo, H O U; Perea martinez, A; Ter-akopian, G; Huyse, M L

The main goal of the present proposal is to measure the continuous spectrum of deuterons emitted in the $\\beta$-decay of $^{6}$He. In particular, we want to focus on the low energy part of the spectrum, below 400 keV, which could not be accessed by all previous experiments. For the decay spectroscopy the Warsaw Optical Time Projection Chamber (OTPC) will be used. The bunches of $^{6}$He ions produced by REX-ISOLDE facility will be implanted into the active volume of the OTPC, where the rare events of deuteron emission will be recorded, practically background free.

The Standard Model and the neutron beta-decay

CERN Document Server

Abele, H

2000-01-01

This article reviews the relationship between the observables in neutron beta-decay and the accepted modern theory of particle physics known as the Standard Model. Recent neutron-decay measurements of various mixed American-British-French-German-Russian collaborations try to shed light on the following topics: the coupling strength of charged weak currents, the universality of the electroweak interaction and the origin of parity violation.

Development of a radiofrequency linear ion trap for {beta} decay study

Energy Technology Data Exchange (ETDEWEB)

Li, G. [McGill Univ., Montreal, Quebec (Canada); Argonne National Laboratory, Argonne, Illinois (United States); Scielzo, N.D. [Lawrence Livermore National Laboratory, Livermore, California (United States); Segel, R.E. [Northwestern Univ., Illinois (United States); and others

2010-07-01

A Beta decay Paul Trap (BPT) has been constructed at Argonne National Laboratory for the precise measurement of beta decay. We have demonstrated the capability of producing and transferring a low-energy, bunched, and isotopically pure ions beam. In BPT the ions are cooled to sub-eV energies, and confined in a volume of less than 1 mm{sup 3}. The trap has an open geometry which allows four sets of radiation detectors covering a substantial potion of solid angle. In combination with versatile detectors, BPT is able to precisely determine the entire decay kinematics of many isotopes. (author)

Limit on neutrinoless ββ decay of 136Xe from the first phase of KamLAND-Zen and comparison with the positive claim in 76Ge.

Science.gov (United States)

Gando, A; Gando, Y; Hanakago, H; Ikeda, H; Inoue, K; Ishidoshiro, K; Kato, R; Koga, M; Matsuda, S; Mitsui, T; Motoki, D; Nakada, T; Nakamura, K; Obata, A; Oki, A; Ono, Y; Otani, M; 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; Freedman, S J; Fujikawa, B K; Han, K; O'Donnell, T; Berger, B E; Efremenko, Y; Karwowski, H J; Markoff, D M; Tornow, W; Detwiler, J A; Enomoto, S; Decowski, M P

2013-02-08

We present results from the first phase of the KamLAND-Zen double-beta decay experiment, corresponding to an exposure of 89.5 kg yr of (136)Xe. We obtain a lower limit for the neutrinoless double-beta decay half-life of T(1/2)(0ν)>1.9×10(25) yr at 90% C.L. The combined results from KamLAND-Zen and EXO-200 give T(1/2)(0ν)>3.4×10(25) yr at 90% C.L., which corresponds to a Majorana neutrino mass limit of <(120-250) meV based on a representative range of available matrix element calculations. Using those calculations, this result excludes the Majorana neutrino mass range expected from the neutrinoless double-beta decay detection claim in (76)Ge, reported by a part of the Heidelberg-Moscow Collaboration, at more than 97.5% C.L.

Weak interaction studies from nuclear beta decay

International Nuclear Information System (INIS)

Morita, M.

1981-01-01

The studies performed at the theoretical nuclear physics division of the Laboratory of Nuclear Studies, Osaka University, are reported. Electron spin density and internal conversion process, nuclear excitation by electron transition, beta decay, weak charged current, and beta-ray angular distributions in oriented nuclei have been studied. The relative intensity of internal conversion electrons for the case in which the radial wave functions of orbital electrons are different for electron spin up and down was calculated. The calculated value was in good agreement with the experimental one. The nuclear excitation following the transition of orbital electrons was studied. The calculated probability of the nuclear excitation of Os 189 was 1.4 x 10 - 7 in conformity with the experimental value 1.7 x 10 - 7 . The second class current and other problems on beta-decay have been extensively studied, and described elsewhere. Concerning weak charged current, the effects of all induced terms, the time component of main axial vector, all partial waves of leptons, Coulomb correction for the electrons in finite size nuclei, and radiative correction were studied. The beta-ray angular distribution for the 1 + -- 0 + transition in oriented B 12 and N 12 was investigated. In this connection, investigation on the weak magnetism to include all higher order corrections for the evaluation of the spectral shape factors was performed. Other works carried out by the author and his collaborators are also explained. (Kato, T.)

Beta decay and rhenium cosmochronology

International Nuclear Information System (INIS)

Ashktorab, K.

1992-01-01

Among the problems which limit the use of the 187 Re/ 187 Os isobaric pair as a cosmochronometer for the age of the galaxy and the universe are the uncertainties in the partial half-lives of the continuum and bound state decays of 187 Re. While the total half-life of the decay is well established, the partial half-life for the continuum decay is uncertain, and several measurements are not compatible. A high temperature quartz proportional counter was used in this work to remeasure the continuum β - decay of 187 Re. The β endpoint energy for the decay of neutral 187 Re to singly ionized 187 Os of 2.75 ± 0.06 keV agrees with the earlier results. The corresponding half-life of (45 ± 3) x 10 9 years improves and agrees with the earlier measurement of Payne and Drever and refutes other measurements. Based on the new half-life for the continuum decay and a total half-life of (43.5 ± 1.3) x 10 9 years reported by Linder et al., the branching ratio for the bound state decay into discrete atomic states is estimated to be (3 ± 6)% in agreement with the most recent calculated theoretical branching ratio of approximately 1%. Anomalies in beta spectra reported by J.J. Simpson and others have been attributed to a 17 keV heavy-neutrino admixture. If confirmed, the implications from the existence of such a neutrino for particle and astrophysics would be significant. A multiwire open-quotes wall-lessclose quotes stainless steel proportional counter has been used in the present work to investigate the spectral shape of the β decay of 63 Ni. No anomalies in the spectral shape were observed which could be attributed to the presence of 17 keV heavy neutrino

The Gotthard experiment on 136Xe ββ decay

International Nuclear Information System (INIS)

Boehm, F.; Busto, J.; Farine, J.; Gabathuler, K.; Gervasio, G.; Henrikson, H.; Joergens, V.; Lou, K.; Luescher, R.; Paic, A.

1995-01-01

The Gotthard experiment measuring the double beta decay of 136 Xe is now running with an improved version of the TPC. The whole charge readout system has been redesigned in order to reduce the radioactive background. Signal-to-noise ratio is further enhanced by the tracking capability that allows to select events with two electron tracks emerging from the same point, and reject with high efficiency those background components such as internal β and α radioactivity, Compton electrons, and cosmic rays. After the first 2200 hours of data taking, a reduction of the count rate has been observed. The most recent 90% C.L. half life limits for the different ββ modes are: 4 x 10 23 yr, corresponding to a Majorana mass of 1.9-2.5 eV, for the neutrinoless channel; 1.1 x 10 22 yr for the majoron, and 4.6 x 10 20 yr for the 2ν channel. (K.A.)

Beta-decay studies at the N=28 shell closure

Czech Academy of Sciences Publication Activity Database

Grévy, S.; Mrázek, Jaromír; Angelique, J. C.; Baumann, P.; Borcea, C.; Buta, A.; Canchel, G.; Cargord, W.; Courtin, S.; Daugas, J. M.; de Oliveira Santos, F.; Dlouhý, Zdeněk; Knipper, A.; Kratz, K. L.; Lecouey, J. L.; Lecolley, F. R.; Lehrsenneau, G.; Lewitowicz, M.; Lienard, E.; Lukianov, S.; Marechal, F.; Miehe, C.; Negoita, F.; Orr, NA.; Pantelica, D.; Penionzhkevich, Y. E.; Peter, J.; Pfeiffer, B.; Pietri, S.; Poirier, E.; Sorlin, O.; Stanoiu, M.; Stodel, C.; Timis, C.

2003-01-01

Roč. 722, - (2003), s. 424C-428C ISSN 0375-9474 R&D Projects: GA AV ČR IAA1048605; GA AV ČR KSK1048102 Institutional research plan: CEZ:AV0Z1048901 Keywords : beta-decay spectroscopy * beta half-lives Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.761, year: 2003

$\\beta$ - decay asymmetry in mirror nuclei: A = 9

CERN Multimedia

Axelsson, L E; Smedberg, M

2002-01-01

Investigations of light nuclei close to the drip lines have revealed new and intriguing features of the nuclear structure. The occurrence of halo structures in loosely bound systems has had a great impact on the nuclear physics research in the last years. As intriguing but not yet solved is the nature of transitions with very large $\\beta$ - strength. \\\\ \\\\We report here on the investigation of this latter feature by an accurate measurement of the $\\beta$ - decay asymmetry between the mirror nuclei in the A=9 mass chain.\\\\ \\\\The possible asymmetry for the decay to the states around 12 MeV is interesting not only due to the fact that the individual B$_{GT}$ values are large (with large overlap in wave-functions, an unambiguous interpretation is much easier made), but also due to the special role played by this transition for the $^{9}$Li decay. It seems to belong to a class of high-B$_{GT}$ transitions observed at the neutron drip line and has been suggested to be due either to a lowering of the giant Gamow-Te...

Beta decay of 31,32Na and 31Mg

International Nuclear Information System (INIS)

Klotz, G.; Baumann, P.; Bounajma, M.; Huck, A.; Knipper, A.; Walter, G.; Poves, A.; Retamosa, J.

1993-01-01

31,32 Na and 31 Mg beta decays were studied at the CERN on-line mass separator ISOLDE by gamma, gamma-gamma and neutron-gamma measurements. In the 31 Na decay, the assignment of previously reported γ transitions and the observation of a new level at 3760 keV lead to a revised decay scheme. In the 31 Mg → 31 Al decay, a new decay scheme involves ten β branches and three states are reported for the first time. New spectroscopic results have been obtained in the 32 Na β - decay. A previously non-interpreted 1436 keV γ ray is now assigned in the 32 Mg scheme. (author) 33 refs., 16 figs., 12 tabs

Program BETA for simulation of particle decays and reactions

International Nuclear Information System (INIS)

Takhtamyshev, G.G.; Merkulova, T.A.

1997-01-01

Program BETA is designed for simulation of particle decays and reactions. The program also produces integration over the phase space and decay rate or the reaction cross section are calculated as a result of such integration. At the simulation process the adaptive random number generator SMART may be used, what is found to be useful for some difficult cases

Beta decay of 22O

International Nuclear Information System (INIS)

Hubert, F.; Dufour, J.P.; Del Moral, R.; Fleury, A.; Jean, D.; Pravikoff, M.S.; Geissel, H.; Schmidt, K.H.; Hanelt, E.

1989-01-01

The study of light nuclei far from stability has been recently renewed by the possibility of production through the projectile fragmentation of intermediate energy heavy ion beams at GANIL. The results presented here have been obtained with the Projectile Fragments Isotopic Separation method developed at the LISE spectrometer. 22 O is a Tz = 3 nucleus and is the first in a series of seven such nuclei in the sd shell extending from 22 O to 24 Mg. Although the half life of 22 O was previously measured by Murphy et al., the present study is the first beta-gamma spectroscopy on this neutron rich nucleus. Five gamma lines have been attributed to the β decay of 22 O with a measured half life of T = (2.25±0.15)s and a partial decay scheme has been established

Beta-delayed gamma and neutron emission near the double shell closure at 78Ni

International Nuclear Information System (INIS)

Rykaczewski, Krzysztof Piotr; Mazzocchi, C.; Grzywacz, R.; Batchelder, J. C.; Bingham, C.R.; Fong, D.; Hamilton, J.H.; Hwang, J.K.; Karny, M.; Krolas, W.; Liddick, S. N.; Morton, A. C.; Mantica, P. F.; Mueller, W. F.; Steiner, M.; Stolz, A.; Winger, J.A.

2005-01-01

An experiment was performed at the National Superconducting Cyclotron Laboratory at Michigan State University to investigate β decay of very neutron-rich cobalt isotopes. Beta-delayed neutron emission from 71-74 Co has been observed for the first time. Preliminary results are reported

First design for the optics of the decay ring for the beta-beams

International Nuclear Information System (INIS)

Chance, A.; Payet, J.

2006-03-01

The aim of the beta-beams is to produce pure electronic neutrino and anti-neutrino highly energetic beams, coming from beta radioactive disintegration decay of the 18 Ne 10+ and 6 He 2+ , directed to experiment situated in the Frejus tunnel. The high ion intensities are stored in a ring, until the ions decay. The losses due to the decay of the radioactive ions are compensated with regular injections. These should be done in presence of the circulating beam. The new ions are injected at a different energy from the stored beam energy, the design of the ring must enable this type of injection and accept the injected and stored beams. In this note, we will focus on the study of the design of such a ring at the first and second orders. We have reached the constraint on the dispersion in the injection section: a horizontal dispersion superior to 10 m with β x = 20 m. We have put sextupoles in the arcs to correct the chromaticity. In the same time, we have compensated the third order resonances to have a large enough dynamic aperture. So the decay ring accepts injected and stored beams. In a top-down approach, the high stored intensities impose to take into account the space charge effects. However, due to the merging, the beam blows up after each injection in the longitudinal space charge, which imposes to include a momentum collimation section in the decay ring

Search for $\\beta$-transitions with the lowest decay energy for a determination of the neutrino mass

CERN Multimedia

From a variety of $\\beta$-transitions only those with decay energies of a few keV and smaller are considered suitable for a determination of the neutrino mass on a sub-eV level. The decay energy of a transition can be very small, if, e.g., in an allowed $\\beta$-decay or electron-capture transition, a nuclear excited state of the daughter nuclide is populated whose energy is very close to the mass difference of the transition nuclides. Investigation of these transitions can also be useful for the assessment of a validity of the current $\\beta$-decay theory in the region of vanishingly small decay energies. The authors of this proposal have found several such $\\beta$-transitions whose decay energies are expected to be extremely small. In order to assess the suitability of these $\\beta$-transitions for the determination of the neutrino mass, measurements of the mass differences of the transition nuclides must be carried out with a sub-keV uncertainty. Presently, only high-precision Penning-trap mass spectrometry...