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Sample records for beta decay half-lives

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

    International Nuclear Information System (INIS)

    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.)

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

    CERN Document Server

    Ren, Yuejiao

    2014-01-01

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

  3. Calculation of beta-decay half-lives of proton-rich nuclei of intermediate mass

    OpenAIRE

    Biehle, G. T.; Vogel, P.

    1992-01-01

    We present the results of a calculation of the beta-decay half-lives of several proton-rich even-even nuclei of intermediate mass: 74Sr, 76Sr, 78Zr, 80Zr, 84Mo, 86Mo, 88Ru, 90Ru, 92Pd, and 96Cd. The calculation is based upon the random phase approximation with the quasiparticle formalism and takes into account the residual particle-particle interaction.

  4. Measurements of beta-decay half-lives of short-lived nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Hirose, T.; Tsurita, Y.; Yamamoto, H.; Kawade, K. [Nagoya Univ. (Japan); Iida, T.; Takahashi, A.; Kasugai, Y.; Ikeda, Y.

    1997-03-01

    The {beta}-decay half-lives of short-lived nuclei produced by 14 MeV neutron bombardments were measured with Ge detectors, a High-rate spectroscopy amplifier (EG and G ORTEC model 973) and a Spectrum multi-scaler (Laboratory equipment corporation SMS-48) in the multi-scaling mode. The adequate corrections for pile-up and dead-time losses were made by applying source and pulser methods. The half-lives of {sup 53}V, {sup 53g}Fe, {sup 89m}Y and {sup 162}Tb were determined with uncertainties of 0.13-0.65%. It has been shown that previous values shorter than 10 min were systematically longer than the present ones. (author)

  5. Nuclear $\\beta^-$-decay half-lives for $fp$ and $f_{5/2}pg_{9/2}$ shell nuclei

    CERN Document Server

    Kumar, Vikas; Li, Hantao

    2016-01-01

    In the present work we calculate the allowed $\\beta^-$-decay half-lives of nuclei with $Z = 20 -30$ and N $\\leq$ 50 systematically under the framework of the nuclear shell model. A recent study shows that some nuclei in this region belonging to the island of inversion. We perform calculation for $fp$ shell nuclei using KB3G effective interaction. In the case of Ni, Cu, and Zn, we used JUN45 effective interaction. Theoretical results of $Q$ values, half-lives, excitation energies, log$ft$ values, and branching fractions are discussed and compared with experimental data. In Ni region, we also compared our calculated results with recent experimental data [Z. Y. Xu {\\it et al.}, \\emph{Phys. Rev. Lett.} \\textbf{113}, 032505, 2014]. Present results showing good agreement with experimental value of half-lives in comparison to QRPA.

  6. HALF-LIVES OF LONG-LIVED ALPHA DECAY, BETA DECAY, ELECTRON CAPTURE DECAY, BETA BETA-DECAY, PROTON DECAY AND SPONTANEOUS FISSION DECAY NUCLIDES.

    Energy Technology Data Exchange (ETDEWEB)

    HOLDEN, H.E.

    2003-08-08

    In his review of radionuclides for dating purposes, Roth noted that there were a large number of nuclides, normally considered ''stable'' but which are radioactive with a very long half-life. Roth suggested that I review the data on the half-life values of these long-lived nuclides for the 2001 Atomic Weights Commission meeting in Brisbane. I provided a report, BNL-NCS-68377, to fulfill Roth's request. Peiser has now made a similar suggestion that I review these data for our next Commission meeting in Ottawa for their possible inclusion in our Tables. These half-life values for long-lived nuclides include those due to various decay modes, {alpha}-decay, {beta}-decay, electron capture decay, {beta}{beta}-decay, proton decay and spontaneous fission decay. This data review (post Brisbane) provides an update to the recommendation of the 2001 review.

  7. Systematic measurement of beta-decay half-lives of short-lived isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Hirose, T.; Yamamoto, H.; Kawade, K. [Nagoya Univ. (Japan); Iida, T.; Takahashi, A.; Kasugai, Y.; Ikeda, Y.

    1997-03-01

    We have measured the half-lives of short-lived isotopes for past decade and deduced the half-lives of 6 isotopes further. These results demonstrated that most of the literature values shorter than 10 min systematically deviated from our measurement ones. The cause seems to be that a large number of the previous half-life studies were performed with scintillation counters before 1970 and they had a difficulty in distinguishing the interest {gamma}-ray from the contamination and correcting for pile-up and dead-time losses. Moreover, the deviated data found to be quoted for evaluation. (author)

  8. Beta-decay half-lives and beta-delayed neutron emission probabilities of nuclei in the region below A=110, relevant for the r-process

    CERN Document Server

    Pereira, J; Aprahamian, A; Arndt, O; Becerril, A; Elliot, T; Estrade, A; Galaviz, D; Kessler, R; Kratz, K -L; Lorusso, G; Mantica, P F; Matos, M; Møller, P; Montes, F; Pfeiffer, B; Schatz, H; Schertz, F; Schnorrenberger, L; Smith, E; Stolz, A; Quinn, M; Walters, W B; Wöhr, A

    2009-01-01

    Measurements of the beta-decay properties of r-process nuclei below A=110 have been completed at the National Superconducting Cyclotron Laboratory, at Michigan State University. Beta-decay half-lives for Y-105, Zr-106,107 and Mo-111, along with beta-delayed neutron emission probabilities of Y-104, Mo-109,110 and upper limits for Y-105, Zr-103,104,105,106,107 and Mo-108,111 have been measured for the first time. Studies on the basis of the quasi-random phase approximation are used to analyze the ground-state deformation of these nuclei.

  9. New phase space calculations for beta-decay half-lives

    CERN Document Server

    Stoica, Sabin; Nitescu, Ovidiu; Nabi, Jameel-Un; Ishfaq, Mavra

    2016-01-01

    We revisit the computation of the phase space factors (PSF) involved in the positron decay and electron capture (EC) processes for a large number of nuclei of experimental interest. To obtain the electron/positron wave functions needed in computation, we develop a code for solving accurately the Dirac equation with a nuclear potential derived from a realistic proton density distribution in the nucleus. The finite nuclear size (FNS) and screening effects are included through recipes which differ from those used in previous calculations. Comparing our results with former calculations employing approximate methods but computed with the same Q-values, we find a close agreement for positron decays, while for the EC process there are relevant differences. For the EC process we also find that the screening effect has a notable influence on the computed PSF values specially for light nuclei. Further, we re-computed the same PSF values but using the most recent Q-values reported in literature. In several cases these n...

  10. Calculation of two-neutrino double beta decay half-lives of 76Ge, 82Se, 96Zr and 100Mo nuclei for the 0+ → 0+ transition

    Science.gov (United States)

    Aytekin, Hüseyin; Yılmaz, Alaaddin

    2015-06-01

    We calculated the half-lives of two-neutrino double beta decay (2ν β β ) of 76Ge, 82Se, 96Zr and 100Mo nuclei for the 0+ ↦ 0+ transition. Quasiparticle random phase approximation (QRPA) was used by considering the charge-exchange spin-spin interactions among the nucleons by considering both particle-hole (p-h) and particle-particle (p-p) channels in the separable form. Calculations were performed for the spherical form of the nuclei.

  11. Self-consistent relativistic quasiparticle random-phase approximation and its applications to charge-exchange excitations and $\\beta$-decay half-lives

    CERN Document Server

    Niu, Z M; Liang, H Z; Long, W H; Meng, J

    2016-01-01

    The self-consistent quasiparticle random-phase approximation (QRPA) approach is formulated in the canonical single-nucleon basis of the relativistic Hatree-Fock-Bogoliubov (RHFB) theory. This approach is applied to study the isobaric analog states (IAS) and Gamov-Teller resonances (GTR) by taking Sn isotopes as examples. It is found that self-consistent treatment of the particle-particle residual interaction is essential to concentrate the IAS in a single peak for open-shell nuclei and the Coulomb exchange term is very important to predict the IAS energies. For the GTR, the isovector pairing can increase the calculated GTR energy, while the isoscalar pairing has an important influence on the low-lying tail of the GT transition. Furthermore, the QRPA approach is employed to predict nuclear $\\beta$-decay half-lives. With an isospin-dependent pairing interaction in the isoscalar channel, the RHFB+QRPA approach almost completely reproduces the experimental $\\beta$-decay half-lives for nuclei up to the Sn isotopes...

  12. Experimental setup and commissioning baseline study in search of time-variations in beta-decay half-lives

    Science.gov (United States)

    Goddard, Braden; Hitt, George W.; Solodov, Alexander A.; Bridi, Dorian; Isakovic, A. F.; El-Khazali, Reyad; Abulail, Ayman

    2016-03-01

    Recently there have been a number of investigations into whether the decay constant of a radioactive isotope can be influenced by external factors, such as the Earth-Sun distance or Solar flare activity. Positive claims suggest that annual oscillations of ~0.1% and accelerations of ~0.4% in the relative activity of beta-emitters coincide with the Earth-Sun distance and solar flare activity, respectively. Results from replication experiments have so far been conflicting. The main criticism of the measurements used to trace and quantify these effects is that the data is of poor quality or limited in scope. Data have often been collected as part of short duration weekly calibration measurements, measured with a single type of low precision detector, only using one isotope, and having no environmental conditions information (temperature, pressure, humidity) accompanying the radiation measurements. This paper describes the setup of a series of counting experiments commissioned for addressing these criticisms. Six dedicated detector systems (four different types) measuring six different isotopes (14C, 54Mn, 60Co, 90Sr, 204Tl, and 226Ra) have been continuously collecting source activity synchronously with environmental data for a period of one month (April 2014). The results of this baseline commissioning study show that there are correlations between activity and environmental conditions for some detector types which are then quantified. The results also show that the one sigma counting uncertainties in all the detectors are less than 0.024% for a given 24 h period. After accounting for propagated uncertainties from corrections against correlations with environmental data, the ability to resolve 0.1% activity changes varies, from 8 min to 1.6 days, depending on the specific detector. All six experiments therefore, will have sufficient precision over the upcoming year to scrutinize claims of both annual activity oscillations and solar flare activity changes.

  13. Calculation of Beta Decay Half-Lives and Delayed Neutron Branching Ratio of Fission Fragments with Skyrme-QRPA

    Directory of Open Access Journals (Sweden)

    Minato Futoshi

    2016-01-01

    Full Text Available Nuclear β-decay and delayed neutron (DN emission is important for the r-process nucleosynthesis after the freeze-out, and stable and safe operation of nuclear reactors. Even though radioactive beam facilities have enabled us to measure β-decay and branching ratio of neutron-rich nuclei apart from the stability line in the nuclear chart, there are still a lot of nuclei which one cannot investigate experimentally. In particular, information on DN is rather scarce than that of T1/2. To predict T1/2 and the branching ratios of DN for next JENDL decay data, we have developed a method which comprises the quasiparticle-random-phase-approximation (QRPA and the Hauser-Feshbach statistical model (HFSM. In this work, we calculate fission fragments with T1/2 ≤ 50 sec. We obtain the rms deviation from experimental half-life of 3:71. Although the result is still worse than GT2 which has been adopted in JENDL decay data, DN spectra are newly calculated. We also discuss further subjects to be done in future for improving the present approach and making next generation of JENDL decay data.

  14. Calculation of Beta Decay Half-Lives and Delayed Neutron Branching Ratio of Fission Fragments with Skyrme-QRPA

    Science.gov (United States)

    Minato, Futoshi

    2016-06-01

    Nuclear β-decay and delayed neutron (DN) emission is important for the r-process nucleosynthesis after the freeze-out, and stable and safe operation of nuclear reactors. Even though radioactive beam facilities have enabled us to measure β-decay and branching ratio of neutron-rich nuclei apart from the stability line in the nuclear chart, there are still a lot of nuclei which one cannot investigate experimentally. In particular, information on DN is rather scarce than that of T1/2. To predict T1/2 and the branching ratios of DN for next JENDL decay data, we have developed a method which comprises the quasiparticle-random-phase-approximation (QRPA) and the Hauser-Feshbach statistical model (HFSM). In this work, we calculate fission fragments with T1/2 ≤ 50 sec. We obtain the rms deviation from experimental half-life of 3:71. Although the result is still worse than GT2 which has been adopted in JENDL decay data, DN spectra are newly calculated. We also discuss further subjects to be done in future for improving the present approach and making next generation of JENDL decay data.

  15. $\\beta$-decay half-lives and nuclear structure of exotic proton-rich waiting point nuclei under $rp$-process conditions

    CERN Document Server

    Nabi, Jameel-Un

    2016-01-01

    We investigate even-even nuclei in the $A\\sim70$ mass region within the framework of the proton-neutron quasi-particle random phase approximation (\\mbox{pn-QRPA}) and the interacting boson model-1 (\\mbox{IBM-1}). Our work includes calculation of the energy spectra and the potential energy surfaces $V(\\beta,\\gamma)$ of Zn, Ge, Se, Kr and Sr nuclei with the same proton and neutron number, $N = Z$. The parametrization of the \\mbox{IBM-1} Hamiltonian was performed for the calculation of the energy levels in the ground state bands. Geometric shape of the nuclei was predicted by plotting the potential energy surfaces $V(\\beta,\\gamma)$ obtained from the \\mbox{IBM-1} Hamiltonian in the classical limit. The \\mbox{pn-QRPA} model was later used to compute half-lives of the neutron-deficient nuclei which were found to be in very good agreement with the measured ones. The \\mbox{pn-QRPA} model was also used to calculate the Gamow-Teller strength distributions and was found to be in decent agreement with the measured data. ...

  16. Comparison of semiempirical formulae for alpha decay half-lives

    International Nuclear Information System (INIS)

    The semiempirical relationships given by Froeman, Wapstra et al., Viola and Seaborg, Hornshoj et al., Taagepera and Nurmia, Keller and Munzel for alpha decay half-lives are compared with experimental results and with a new formula derived by the authors form the fission theory of alpha decay in even-even, odd-even, even-odd and odd-odd nuclei. By taking into consideration the shell effects, the new formula allows one to obtain a better agreement with experimental data, even in the neighbourhood of the magic numbers

  17. α-decay half-lives study of superheavy nuclei

    International Nuclear Information System (INIS)

    Now a days, the synthesis of superheavy nuclei (SHN) has become an outstanding research topic in nuclear physics. Since the predictions of the existence of superheavy island in 1960s. In recent years, much experimental progress has been made in synthesizing SHN with atomic number Z=114-118 by hot fusion reactions. α-decay is the most powerful tool in studying exotic nuclei in the superheavy region as it can provide some reliable knowledge on the nuclear structure and is used to identify new isotopes when an unknown parent nucleus decays to a known daughter nucleus. In this paper, we calculate the α-decay half-lives of some SHN by considering the unstable parent nucleus as a quantum two-body system of the ejected α particle and the daughter nucleus exhibiting resonance scattering phenomena under the combined effect of nuclear, coulomb and centrifugal forces. Finally, predictions within the same frame work are given for the α-decay half-lives of nuclei having Z=120-126 are made for future experiments

  18. Beta Decay Study of the Tz=−256Zn Nucleus and the Determination of the Half-Lives of a Few fp-shell Nuclei

    International Nuclear Information System (INIS)

    This paper concerns the experimental study of the β decay properties of few proton-rich fp-shell nuclei. The nuclei were produced at GANIL in fragmentation reactions, separated with the LISE spectrometer and stopped in an implantation detector surrounded by Ge detectors. The β-delayed gammas, β-delayed protons and the exotic β-delayed gamma-proton emission have been studied. Preliminary results are presented. The decay of the Tz=−2 nucleus 56Zn has been studied in detail. Information from the β-delayed protons and β-delayed gammas has been used to deduce the decay scheme. The exotic beta-delayed gamma-proton decay has been observed for the first time in the fp-shell. The interpretation of the data was made possible thanks to the detailed knowledge of the mirror Charge Exchange (CE) process and the gamma de-excitation of the states in 56Co, the mirror nucleus of 56Cu

  19. Phenomenological formula for alpha-decay half-lives

    International Nuclear Information System (INIS)

    A phenomenological formula is presented for the partial half-life from the Q value for α decay. It is constructed in a conventional way by considering the penetrability of a charged particle in a spherical Coulomb potential. Parameters in the formula are fixed because they are determined by physical constants except for the following three adjustable parameters: the product of the collision frequency of an α particle and the formation probability, N; the distance between the charge radius and the radius of an inner point of the Coulomb barrier, r 0; and the odd-mass hindrance, h 0. The values obtained for the three adjustable parameters are reasonable, in contrast with those of conventional models such as the Viola-Seaborg formula. The root-mean-square deviations from experimental partial half-lives for even-even, odd-A, and odd-odd nuclei are 0.344, 0.740, and 0.940 (in log10), respectively. The obtained formula gives half-lives that are two or three times longer than those obtained using the Viola-Seaborg formula in the superheavy nuclear mass region. (author)

  20. Beta-decay half-lives of neutron rich Cu and Ni isotopes produced by thermal fission of 235U and 239Pu

    International Nuclear Information System (INIS)

    The half-lives of very neutron rich isotopes of Ni and Cu have been measured. The isotopes are produced in very asymmetric thermal fission of 235U and 239Pu at the I.L.L. high flux reactor. They are separated by means of the Lohengrin spectrometer. They are identified with a ΔE-E ionization chamber and implanted in one of the 8 Si planar detectors where the β- particles are also detected. The time correlations between the implantation and the detection of β- particles provide the half-life. The values obtained are compared to current theoretical predictions

  1. Empirical description of beta-delayed fission partial half-lives

    CERN Document Server

    Ghys, L; Antalic, S; Huyse, M; Van Duppen, P

    2015-01-01

    Background: The process of beta-delayed fission (bDF) provides a versatile tool to study low-energy fission in nuclei far away from the beta-stability line, especially for nuclei which do not fission spontaneously. Purpose: The aim of this paper is to investigate systematic trends in bDF partial half-lives. Method: A semi-phenomenological framework was developed to systematically account for the behavior of bDF partial half-lives. Results: The bDF partial half-life appears to exponentially depend on the difference between the Q value for beta decay of the parent nucleus and the fission-barrier energy of the daughter (after beta decay) product. Such dependence was found to arise naturally from some simple theoretical considerations. Conclusions: This systematic trend was confirmed for experimental bDF partial half-lives spanning over 7 orders of magnitudes when using fission barriers calculated from either the Thomas-Fermi or the liquid-drop fission model. The same dependence was also observed, although less p...

  2. alpha-nucleus potentials, alpha-decay half-lives, and shell closures for superheavy nuclei

    OpenAIRE

    Mohr, Peter

    2006-01-01

    Systematic alpha-nucleus folding potentials are used to analyze alpha-decay half-lives of superheavy nuclei. Preformation factors of about several per cent are found for all nuclei under study. The systematic behavior of the preformation factors and the volume integrals of the potentials allows to predict alpha-decay energies and half-lives for unknown nuclei. Shell closures can be determined from measured alpha-decay energies using the discontinuity of the volume integral at shell closures. ...

  3. Nuclear β-decay half-lives in the relativistic point-coupling model

    Science.gov (United States)

    Wang, Z. Y.; Niu, Y. F.; Niu, Z. M.; Guo, J. Y.

    2016-08-01

    The self-consistent proton-neutron quasiparticle random phase approximation approach is employed to calculate β-decay half-lives of neutron-rich even-even nuclei with 8≤slant Z≤slant 30. A newly proposed nonlinear point-coupling effective interaction PC-PK1 is used in the calculations. It is found that the isoscalar proton-neutron pairing interaction can significantly reduce β-decay half-lives. With an isospin-dependent isoscalar proton-neutron pairing strength, our results well reproduce the experimental β-decay half-lives, although the pairing strength is not adjusted using the half-lives calculated in this study.

  4. α decay energies and half-lives from a macroscopic-microscopic model

    Institute of Scientific and Technical Information of China (English)

    PENG Jin-Song; LI Lu-Lu; ZHOU Shan-Gui; ZHAO En-Guang

    2008-01-01

    α decay energies of 323 heavy nuclei with Z≥82 are evaluated with a macroscopic-microscopic model.In this model,the macroscopic part is treated by the continuous medium model and the microscopic part consists of shell and pairing corrections based on the Nilsson potential.α decay half-lives are calculated by Viola-Seaborg formula.The results of α decay energies and half-lives are compared with experimental values and satisfactory agreement is found.The recoiling effect of the daughter nucleus on α decay half-life is also discussed.

  5. Study of alpha-decay half-lives with deformed, oriented daughter nuclei

    International Nuclear Information System (INIS)

    In this paper, Coulomb and proximity potential model has been applied to calculate the half-lives of alpha-decay for isotopes around N = Z = 50. Using this model, we investigated the influence of deformation and orientation of daughter nucleus on alpha-decay half-lives. Two orientations (90° and 180°) with quadrupole deformation are applied to study the role of daughter orientation in alpha-decay process. It is found that the deformation and orientation of daughter nucleus affects the alpha-decay half-life and changes the slope and intercept of linear relation between log10(T1/2) and Q-1/2. (author)

  6. β+ decay and cosmic-ray half-lives of 143Pm and 144Pm

    International Nuclear Information System (INIS)

    The positron decay partial half-lives of 143Pm and 144Pm are needed to assess the viability of elemental Pm as a cosmic-ray clock. We have conducted experiments to measure the β+ branches of these isotopes; we find β+ branches of -6% for 143Pm and -5% for 144Pm. Although these branches are a factor of 20 lower than the previous experimental limits, the resulting partial half-lives are still too uncertain to permit any firm conclusions

  7. Systematic study of α -decay energies and half-lives of superheavy nuclei

    Science.gov (United States)

    Wang, Y. Z.; Wang, S. J.; Hou, Z. Y.; Gu, J. Z.

    2015-12-01

    Systematic calculations on the α -decay energies (Qα) and α -decay half-lives of the superheavy nuclei (SHN) with Z ≥100 are performed by using 20 models and 18 empirical formulas, respectively. According to the comparisons between the calculated results and experimental data, it is shown that the WS4 mass model is the most accurate one to reproduce the experimental Qα values of the SHN. Meanwhile it is found that the SemFIS2 formula is the best one to predict the α -decay half-lives of the SHN because the parameters in this formula are from the experimental α emitter data of transuranium nuclei including SHN (Z =92 -118 ). In addition, the UNIV2 formula with fewest parameters and the VSS, SP and NRDX formulas with fewer parameters work well in prediction on the SHN α -decay half-lives. Finally, the α -decay half-lives of Z =110 -120 isotopes are predicted within the above mentioned five formulas by inputting the WS 4 Qα values. By analyzing the Qα values and the α -decay half-lives of this region, it is found that for Z =110 -114 isotopes N =162 and N =184 are the submagic number and magic number, respectively. However, for the isotopes of Z =116 -120 the submagic number is N =178 .

  8. Alpha decay potential barriers and half-lives and analytical formula predictions for superheavy nuclei

    International Nuclear Information System (INIS)

    The α decay potential barriers are determined in the cluster-like shape path within a generalized liquid drop model including the proximity effects between the α particle and the daughter nucleus and adjusted to reproduce the experimental Qα. The α emission half-lives are determined within the WKB penetration probability. Calculations using previously proposed formulae depending only on the mass and charge of the alpha emitter and Qα are also compared with new experimental alpha-decay half-lives. The agreement allows to provide predictions for the α decay half-lives of other still unknown superheavy nuclei using the Qα determined from the 2003 atomic mass evaluation of Audi, Wapstra and Thibault. (author)

  9. Empirical description of beta-delayed fission partial half-lives

    OpenAIRE

    Ghys, Lars; Andreyev, A.N.; Antalic, S; Huyse, Mark; Van Duppen, Piet

    2015-01-01

    Background: The process of beta-delayed fission (bDF) provides a versatile tool to study low-energy fission in nuclei far away from the beta-stability line, especially for nuclei which do not fission spontaneously. Purpose: The aim of this paper is to investigate systematic trends in bDF partial half-lives. Method: A semi-phenomenological framework was developed to systematically account for the behavior of bDF partial half-lives. Results: The bDF partial half-life appears to exponentially de...

  10. Half-lives with Yukawa proximity potential for alpha-decay process

    International Nuclear Information System (INIS)

    We intend to study the alpha-decay half-lives of some nuclei from ground state to ground state. We consider a potential model with Yukawa proximity potential. We see that the results are in good agreement with the experimental data. (author)

  11. Systematic calculation of α-decay half-lives within generalized density-dependent cluster model

    International Nuclear Information System (INIS)

    An improved version of the generalized density-dependent cluster model is presented to describe an α particle tunneling through a microscopic potential barrier. The microscopic potential is numerically constructed in the double folding model for both the Coulomb potential and the nuclear potential. The decay width is computed using the integral of the quasibound state wave function, the scattering state wave function, and the difference of potentials. We perform a systematic calculation of α-decay half-lives for even-even, odd-A, and odd-odd nuclei ranging from N = 84 to N = 126. The calculated α-decay half-lives are found to be in good agreement with the experimental values. (author)

  12. Extended systematics of alpha decay half lives for exotic superheavy nuclei

    CERN Document Server

    Budaca, A I; Silisteanu, I

    2016-01-01

    The experimentally available data on the alpha decay half lives and Q? values for 96 superheavy nuclei are used to fix the parameters for a modified version of the Brown empirical formula through two fitting procedures which enables its comparison with similar fits using Viola-Seaborg and Royer formulas. The new expressions provide very good agreement with experimental data having fewer or the same number of parameters. All formulas with the obtained parameters are then extrapolated to generate half lives predictions for 125 unknown superheavy alpha emitters. The nuclei where the employed empirical formulas maximally or minimally diverge are pointed out and a selection of 36 nuclei with exceptional superposition of predictions was made for experimental reference.

  13. Evaluation of half-lives and average decay energies for short-lived fission product nuclides

    International Nuclear Information System (INIS)

    β-decay half-lives T1/2, average β-energies E-barβ, and average γ-energies E-barγ, which are essential for the decay heat, are calculated with use of an improved gross theory of β-decay. First, the improvement of the gross theory is explained, and then T1/2, E-barβ, and E-barγ are tabulated for β--decay nuclides with 26 < Z(proton number) < 65 and N(neutron number) < (147/92)Z + 6 except for those with small Q-value. The β-decay Q-values used in this calculation are obtained from the Wapstra-Audi mass evaluation and a mass formula newly constructed by Tachibana et al. Figures are given to indicate how the results depend on the parameters in the model. (author)

  14. Cluster decay half lives of trans-lead nuclei within the Coulomb and proximity potential model

    CERN Document Server

    Santhosh, K P; Unnikrishnan, M S

    2012-01-01

    Within the Coulomb and proximity potential model (CPPM) the cluster decay process in {199-226}^Fr, {206-232}^Ac, {209-237}^Th, {212-238}^Pa, {217-241}^U, {225-242}^Np, {225-244}^Pu, {231-246}^Am, {202-230}^Ra and {233-249}^Cm isotopes leading to the doubly magic 208^Pb and neighbouring nuclei are studied. The computed half lives are compared with available experimental data and are in good agreement with each other. The half lives are also computed using the Universal formula for cluster decay (UNIV) of Poenaru et al, Universal decay law (UDL) and the scaling law of Horoi et al, and their comparisons with CPPM values are found to be in agreement. The calculations for the emission of 22^O, 20^O, 20^O from the parents {209-237}^Th, {202-230}^Ra and {217-240}^U respectively were the experimental values are not available are also done. It is found that most of the decay modes are favourable for measurement, and this observation will serve as a guide to the future experiments. The odd-even staggering (OES) are fou...

  15. Cluster Decay Half-Lives of 5d Transition Metal Nuclei Using the Coulomb and Proximity Potential Model

    CERN Document Server

    Mageed, K E Abd El; Gado, K A; Shalaby, Asmaa G

    2016-01-01

    We have applied the Coulomb and proximity potential model,CPPM to calculate the half lives for various clusters decay of the selected even-even isotopes of the chosen nuclei. These nuclei are Hf, W, Os, Pt, and Hg in the 5d transition metal region in the periodic table with atomic number 72 greater or equal Z less than or equal 80. Furthermore, the half-lives are calculated using the universal formula for cluster decay. The calculated half-lives of alpha decay for the chosen isotopes are in good agreement with the experimental data, especially with the CPPM results. The alpha and cluster decays are more probable from the parents in the heavier mass number A equal 168,180 than from the parents in the lighter mass number A equal 156, 166.

  16. Systematic study of α decay half-lives for even-even nuclei within a two-potential approach

    Science.gov (United States)

    Sun, Xiao-Dong; Guo, Ping; Li, Xiao-Hua

    2016-03-01

    α decay is a common and important process of natural radioactivity of heavy and superheavy nuclei. The α decay half-lives for even-even nuclei from Z =62 to Z =118 are systematically studied based on the two-potential approach with a quasistationary state approximation. As for the nuclear potential, the isospin effect is considered, which slightly improves the results by 6.8%. To reduce the deviations between experimental half-lives and calculated results due to the nuclear shell structure, the analytic expression of hindrance factors is employed. Our results can reproduce the experimental half-lives as good as using the density-dependent cluster model and the generalized liquid drop model.

  17. Double beta decay experiments

    International Nuclear Information System (INIS)

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

  18. Systematic study of $\\alpha$ decay half-lives for even-even nuclei within a two-potential approach

    CERN Document Server

    Sun, Xiao-Dong; Li, Xiao-Hua

    2015-01-01

    $\\alpha$ decay is a common and important process for natural radioactivity of heavy and superheavy nuclei. The $\\alpha$ decay half-lives for even-even nuclei from Z=62 to Z=118 are systematically researched based on the two-potential approach with a quasi-stationary state approximation. To describe the deviations between experimental half-lives and calculated results due to the nuclear shell structure, a hindrance factor related with $\\alpha$ particle preformation probability is introduced. Our results can well reproduce the experimental data equally to the density-dependent cluster model and the generalized liquid drop model. We also study the isospin effect of nuclear potential in this work. Considering the isospin effect the calculated results improved about 7.3$\\%$.

  19. Structure effects in the calculation of beta strength functions and half lives of Rb and Br isotopes

    International Nuclear Information System (INIS)

    The properties of beda delayed neutron emission of the precursors around mass 95 are investigated using spherical Shell Model plus pairing. The objective of this work is to find out the important parameters that effect these properties. The strength functions and half lives of both even and odd Rb and Br precursors are calculated in BCS quasi-particle theory as well as in Seniority Truncated Exact Diagonalization (STED) scheme. The calculated half lives from the two schemes are in close agreement with each other. STED gave much smoother overall trend which is in better agreement with experimental values. The calculations reveal that the so called 'odd decays' which depend in an essential way on the parent ground state configuration are of crucial importance in determining both half life, t/sub 1/2/ and delayed neutron emission probability, P/sub n/. Furthermore, it is shown that it is not possible to choose apriori global set for the single particle Shell model basis to predict the correct ground state configurations for both the odd and even nuclei. Instead, it is necessary to examine available experimental evidence in order to construct a more valid global set for single particle basis. The significant variations of the predicted half lives according to the different parent ground-state configuration choices, reveal the importance of nuclear structure effects in these isotopes. The calculated t/sub 1/2/ and P/sub n/ of Rb and Br precursors are presented, discussed and compared with experimental values

  20. Half-lives for proton emission, alpha decay, cluster radioactivity, and cold fission processes calculated in a unified theoretical framework

    International Nuclear Information System (INIS)

    Half-life values of spontaneous nuclear decay processes are presented in the framework of the Effective Liquid Drop Model (ELDM) using the combination of varying mass asymmetry shape description for the mass transfer with Werner-Wheeler's inertia coefficient VMAS/WW. The calculated half-lives of ground-state to ground-state transitions for the proton emission, alpha decay, cluster radioactivity, and cold fission processes are compared with experimental data. Results have shown that the ELDM is a very efficient model to describe these different decay processes in a same, unified theoretical framework. A Table listing the predicted half-life values, τc is presented for all possible cases of spontaneous nuclear break-up such that -7.30 10 τc [S] 10(τ/τc) > -17.0, where τ is the total half-life of the parent nucleus. (author)

  1. Cluster decay half-lives of trans-lead nuclei within the Coulomb and proximity potential model

    International Nuclear Information System (INIS)

    Within the Coulomb and proximity potential model (CPPM) the cluster decay process in 199-226Fr, 206-232Ac, 209-237Th, 212-238Pa, 217-241U, 225-242Np, 225-244Pu, 231-246Am, 202-230Ra and 233-249Cm isotopes leading to the doubly magic 208Pb and neighboring nuclei are studied. The computed half-lives are compared with available experimental data and are in good agreement with each other. The half-lives are also computed using the Universal formula for cluster decay (UNIV) of Poenaru et al., Universal Decay Law (UDL) and the Scaling Law of Horoi et al., and their comparisons with CPPM values are found to be in agreement. The calculations for the emission of 22O from the parent 209-237Th, 20O from the parents 202-230Ra and 217-240U, were the experimental values are not available are also done. It is found that most of the decay modes are favorable for measurement (T1/230 s), and this observation will serve as a guide to the future experiments. The odd-even staggering (OES) are found to be more prominent in the emission of odd mass clusters. The Geiger-Nuttall plots of log10(T1/2) versus Q-1/2 for various clusters ranging from 14C to 34Si from different isotopes of heavy parent nuclei with atomic numbers within the range 87⩽Z⩽96 have been studied and are found to be linear. Our study reveals the role of doubly magic 208Pb daughter nuclei in cluster decay process and also reveal the fact that the role of neutron shell closure is crucial than proton shell closure.

  2. Half-lives for proton emission, alpha decay, cluster radioactivity, and cold fission processes calculated in a unified theoretical framework

    Energy Technology Data Exchange (ETDEWEB)

    Duarte, S.B.; Tavares, O.A.P.; Guzman, F.; Dimarco, A. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil); Garcia, F. [Sao Paulo Univ., SP (Brazil). Inst. de Fisica; Universidade Estadual de Santa Cruz, Ilheus, BA (Brazil). Dept. de Ciencias Exatas e Tecnologicas; Rodriguez, O. [Sao Paulo Univ., SP (Brazil). Inst. de Fisica; Instituto Superior de Ciencias e Tecnologia Nucleares, La Habana (Cuba); Goncalves, M. [Instituto de Radioprotecao e Dosimetria (IRD), Rio de Janeiro, RJ (Brazil)

    2002-01-01

    Half-life values of spontaneous nuclear decay processes are presented in the framework of the Effective Liquid Drop Model (ELDM) using the combination of varying mass asymmetry shape description for the mass transfer with Werner-Wheeler's inertia coefficient V{sub MAS}/WW. The calculated half-lives of ground-state to ground-state transitions for the proton emission, alpha decay, cluster radioactivity, and cold fission processes are compared with experimental data. Results have shown that the ELDM is a very efficient model to describe these different decay processes in a same, unified theoretical framework. A Table listing the predicted half-life values, {tau}{sub c} is presented for all possible cases of spontaneous nuclear break-up such that -7.30 <{approx_equal} log{sub 10} {tau}{sub c} [S] <{approx_equal} 27.50 and log {sub 10}({tau}/{tau}{sub c}) > -17.0, where {tau} is the total half-life of the parent nucleus. (author)

  3. Imperfect World of beta beta-decay Nuclear Data Sets

    Energy Technology Data Exchange (ETDEWEB)

    Pritychenko, B. [Brookhaven National Lab. (BNL), Upton, NY (United States). NNDC

    2015-01-03

    The precision of double-beta ββ-decay experimental half lives and their uncertainties is reanalyzed. The method of Benford's distributions has been applied to nuclear reaction, structure and decay data sets. First-digit distribution trend for ββ-decay T2v1/2 is consistent with large nuclear reaction and structure data sets and provides validation of experimental half-lives. A complementary analysis of the decay uncertainties indicates deficiencies due to small size of statistical samples, and incomplete collection of experimental information. Further experimental and theoretical efforts would lead toward more precise values of-decay half-lives and nuclear matrix elements.

  4. Status and perspectives of double beta decay searches

    International Nuclear Information System (INIS)

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

  5. Half-lives and branchings for {\\beta}-delayed neutron emission for neutron-rich Co-Cu isotopes in the r-process

    CERN Document Server

    Hosmer, P; Aprahamian, A; Arndt, O; Clement, R R C; Estrade, A; Farouqi, K; Kratz, K -L; Liddick, S N; Lisetskiy, A F; Mantica, P F; Möller, P; Mueller, W F; Montes, F; Morton, A C; Ouellette, M; Pellegrini, E; Pereira, J; Pfeiffer, B; Reeder, P; Santi, P; Steiner, M; Stolz, A; Tomlin, B E; Walters, W B; Wöhr, A; 10.1103/PhysRevC.82.025806

    2010-01-01

    The {\\beta} decays of very neutron-rich nuclides in the Co-Zn region were studied experimentally at the National Superconducting Cyclotron Laboratory using the NSCL {\\beta}-counting station in conjunction with the neutron detector NERO. We measured the branchings for {\\beta}-delayed neutron emission (Pn values) for 74Co (18 +/- 15%) and 75-77Ni (10 +/- 2.8%, 14 +/- 3.6%, and 30 +/- 24%, respectively) for the first time, and remeasured the Pn values of 77-79Cu, 79,81Zn, and 82Ga. For 77-79Cu and for 81Zn we obtain significantly larger Pn values compared to previous work. While the new half-lives for the Ni isotopes from this experiment had been reported before, we present here in addition the first half-life measurements of 75Co (30 +/- 11 ms) and 80Cu (170+110 -50 ms). Our results are compared with theoretical predictions, and their impact on various types of models for the astrophysical rapid neutron-capture process (r-process) is explored. We find that with our new data, the classical r-process model is bet...

  6. $\\beta$-decay study of $^{77}$Cu

    CERN Document Server

    Patronis, N; Górska, M; Huyse, M; Kruglov, K; Pauwels, D; Van de Vel, K; Van Duppen, P; Van Roosbroeck, J; Thomas, J-C; Franchoo, S; Cederkäll, J; Fedosseev, V; Fynbo, H; Georg, U; Jonsson, O; Köster, U; Materna, T; Mathieu, L; Serot, O; Weissman, L; Müller, W F; Mishin, V I; Fedorov, D

    2009-01-01

    A beta-decay study of Cu-77 has been performed at the ISOLDE mass separator with the aim to deduce its beta-decay properties and to obtain spectroscopic information on Zn-77. Neutron-rich copper isotopes were produced by means of proton- or neutron-induced fission reactions on U-238. After the production, Cu-77 was selectively laser ionized, mass separated and sent to different detection systems where beta-gamma and beta-n coincidence data were collected. We report on the deduced half-live, decay scheme, and possible spin assignment of 77Cu.

  7. Recent activities for β-decay half-lives and β-delayed neutron emission of very neutron-rich isotopes

    International Nuclear Information System (INIS)

    Beta-delayed neutron (βn) emitters play an important, two-fold role in the stellar nucleosynthesis of heavy elements in the 'rapid neutron-capture process' (r process). On one hand they lead to a detour of the material β-decaying back to stability. On the other hand, the released neutrons increase the neutron-to-seed ratio, and are re-captured during the freeze-out phase and thus influence the final solar r-abundance curve. A large fraction of the isotopes inside the r-process reaction path are not yet experimentally accessible and are located in the (experimental) 'Terra Incognita'. With the next generation of fragmentation and ISOL facilities presently being built or already in operation, one of the main motivation of all projects is the investigation of these very neutron-rich isotopes. A short overview of one of the planned programs to measure βn-emitters at the limits of the presently know isotopes, the BRIKEN campaign (Beta delayed neutron emission measurements at RIKEN) will be given. Presently, about 600 β-delayed one-neutron emitters are accessible, but only for a third of them experimental data are available. Reaching more neutron-rich isotopes means also that multiple neutron-emission becomes the dominant decay mechanism. About 460 β-delayed two-, three-or four-neutron emitters are identified up to now but for only 30 of them experimental data about the neutron branching ratios are available, most of them in the light mass region below A=30. The International Atomic and Energy Agency (IAEA) has identified the urgency and picked up this topic recently in a 'Coordinated Research Project' on a 'Reference Database for Beta-Delayed Neutron Emission Data'. This project will review, compile, and evaluate the existing data for neutron-branching ratios and half-lives of β-delayed neutron emitters and help to ensure a reliable database for the future discoveries of new isotopes and help to constrain astrophysical and theoretical models

  8. Nuclear Decay Data for the International Reactor Dosimetry Library for Fission and Fusion (IRDFF): Updated Evaluations of the Half-Lives and Gamma Ray Intensities

    Science.gov (United States)

    Chechev, Valery P.; Kuzmenko, Nikolay K.

    2016-02-01

    Updated evaluations of the half-lives and prominent gamma ray intensities have been presented for 20 radionuclides - dosimetry reaction residuals. The new values of these decay characteristics recommended for the IRDFF library were obtained using the approaches and methodology adopted by the working group of the Decay Data Evaluation Project (DDEP) cooperation. The experimental data published up to 2014 were taken into account in updated evaluations. The list of radionuclides includes 3H, 18F, 22Na, 24Na, 46Sc, 51Cr, 54Mn, 59Fe, 57Co, 60Co, 57Ni, 64Cu, 88Y, 132Te, 131I, 140Ba, 140La, 141Ce, 182Ta, 198Au.

  9. Evaluation of Beta-Delayed Neutron Emission Probabilities and Half-Lives for Z = 2–28

    Energy Technology Data Exchange (ETDEWEB)

    Birch, M. [Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1 (Canada); Singh, B., E-mail: ndgroup@mcmaster.ca [Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1 (Canada); Dillmann, I. [TRIUMF, Vancouver, British Columbia V6T 2A3 (Canada); Abriola, D. [Department of Physics, TANDAR Laboratory, C.N.E.A., Buenos Aires (Argentina); Johnson, T.D.; McCutchan, E.A.; Sonzogni, A.A. [National Nuclear Data Center, Brookhaven National Laboratory, Upton, NY 11973-5000 (United States)

    2015-09-15

    We present an evaluation and compilation of β-delayed neutron probabilities and half-lives for nuclei in the region Z = 2–28 ({sup 8}He–{sup 80}Ni). This article includes the recommended values of these quantities as well as a compiled list of experimental measurements for each nucleus in the region for which β-delayed neutron emission is possible. The literature cut-off for this work is August 15{sup th}, 2015. Some notable cases as well as new standards for β-delayed neutron measurements in this mass region are also discussed.

  10. Evaluation of Beta-Delayed Neutron Emission Probabilities and Half-Lives for Z = 2–28

    International Nuclear Information System (INIS)

    We present an evaluation and compilation of β-delayed neutron probabilities and half-lives for nuclei in the region Z = 2–28 (8He–80Ni). This article includes the recommended values of these quantities as well as a compiled list of experimental measurements for each nucleus in the region for which β-delayed neutron emission is possible. The literature cut-off for this work is August 15th, 2015. Some notable cases as well as new standards for β-delayed neutron measurements in this mass region are also discussed

  11. Predictions on the alpha decay half lives of Superheavy nuclei with Z = 113 in the range 255 l.e. A l.e. 314

    CERN Document Server

    Santhosh, K P; Nithya, C; Priyanka, B

    2016-01-01

    An intense study of the alpha decay properties of the isotopes of superheavy element Z=113 have been performed within the Coulomb and proximity potential model for deformed nuclei (CPPMDN) within the wide range 255 l.e. A l.e. 314. The predicted alpha decay half lives of $^{278}$113 and $^{282}$113 and the alpha half lives of their decay products are in good agreement with the experimental data. 6{\\alpha) chains and 4{\\alpha} chains predicted respectively for $^{278}$113 and $^{282}$113 are in agreement with the experimental observation. Our study shows that the isotopes in the mass range 278 l.e. A l.e. 286 will survive fission and can be synthesized and detected in the laboratory via alpha decay. In our study, we have predicted 6{\\alpha} chains from $^{279}$113, 4{\\alpha} chains from $^{286}$113, 3{\\alpha} chains from $^{280,281,283}$113, 2{\\alpha} chains from $^{284}$113 and 1{\\alpha} chain from $^{285}$113. We hope that these predictions will be a guideline for future experimental investigations.

  12. Microscopic calculations for rare beta decays

    OpenAIRE

    Mustonen, Mika

    2010-01-01

    In this thesis consisting of six publications and an overview part, three cases of rare beta decays are studied using microscopic nuclear models. Firstly, the half-lives and electron spectra of 113Cd and 115In fourth-forbidden nonunique ground-state-to-ground-state beta decays are studied using two closely related nuclear models: The microscopic quasiparticle-phonon model (MQPM) and the proton-neutron MQPM (pnMQPM), which has been developed as a part of this thesis work. Our...

  13. Nuclear Decay Data for the International Reactor Dosimetry Library for Fission and Fusion (IRDFF: Updated Evaluations of the Half-Lives and Gamma Ray Intensities

    Directory of Open Access Journals (Sweden)

    Chechev Valery P.

    2016-01-01

    Full Text Available Updated evaluations of the half-lives and prominent gamma ray intensities have been presented for 20 radionuclides – dosimetry reaction residuals. The new values of these decay characteristics recommended for the IRDFF library were obtained using the approaches and methodology adopted by the working group of the Decay Data Evaluation Project (DDEP cooperation. The experimental data published up to 2014 were taken into account in updated evaluations. The list of radionuclides includes 3H, 18F, 22Na, 24Na, 46Sc, 51Cr, 54Mn, 59Fe, 57Co, 60Co, 57Ni, 64Cu, 88Y, 132Te, 131I, 140Ba, 140La, 141Ce, 182Ta, 198Au.

  14. Systematic study of favored \\alpha-decay half-lives of closed shell odd-A and doubly-odd nuclei related to ground and isomeric states

    CERN Document Server

    Sun, Xiao-Dong; Li, Xiao-Hua

    2016-01-01

    In this work, we systematically investigate the favored $\\alpha$-decay half-lives and $\\alpha$ preformation probabilities of both odd-$A$ and doubly-odd nuclei related to ground and isomeric states around the doubly magic cores at $Z=82$, $N=82$ and at $Z=82$, $N=126$, respectively, within a two-potential approach from the view of the valence nucleon (or hole). The results show that the $\\alpha$ preformation probability is linear related to $N_\\text{p}N_\\text{n}$ or $N_\\text{p}N_\\text{n}I$, where $N_\\text{p}$, $N_\\text{n}$, and $I$ are the number of valence protons (or holes), the number of valence neutrons (or holes), and the isospin of the parent nucleus, respectively. Fitting the $\\alpha$ preformation probabilities data extracted from the differences between experimental data and calculated half-lives without a shell correction, we give two analytic formulas of the $\\alpha$ preformation probabilities and the values of corresponding parameters. Using those formulas and the parameters, we calculate the $\\alp...

  15. Nuclear $\\beta^+$/EC decays in covariant density functional theory and the impact of isoscalar proton-neutron pairing

    CERN Document Server

    Niu, Z M; Liu, Q; Liang, H Z; Guo, J Y

    2013-01-01

    Self-consistent proton-neutron quasiparticle random phase approximation based on the spherical nonlinear point-coupling relativistic Hartree-Bogoliubov theory is established and used to investigate the $\\beta^+$/EC-decay half-lives of neutron-deficient Ar, Ca, Ti, Fe, Ni, Zn, Cd, and Sn isotopes. The isoscalar proton-neutron pairing is found to play an important role in reducing the decay half-lives, which is consistent with the same mechanism in the $\\beta$ decays of neutron-rich nuclei. The experimental $\\beta^+$/EC-decay half-lives can be well reproduced by a universal isoscalar proton-neutron pairing strength.

  16. Double beta decay experiments

    OpenAIRE

    Barabash, A. S.

    2011-01-01

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

  17. Beta-decay properties of Zr and Mo neutron-rich isotopes

    OpenAIRE

    Sarriguren, P.; Pereira, J

    2010-01-01

    Gamow-Teller strength distributions, beta-decay half-lives, and beta-delayed neutron emission are investigated in neutron-rich Zr and Mo isotopes within a deformed quasiparticle random-phase approximation. The approach is based on a self-consistent Skyrme Hartree-Fock mean field with pairing correlations and residual separable particle-hole and particle-particle forces. Comparison with recent measurements of half-lives stresses the important role that nuclear deformation plays in the descript...

  18. Empirical formula for two neutrino double beta decay

    International Nuclear Information System (INIS)

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

  19. Neutrinoless double beta decay

    International Nuclear Information System (INIS)

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

  20. Neutrinoless double beta decay

    Indian Academy of Sciences (India)

    Kai Zuber

    2012-10-01

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

  1. LHC dijet constraints on double beta decay

    CERN Document Server

    Helo, J C

    2015-01-01

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

  2. Beta-decay properties of Zr and Mo neutron-rich isotopes

    CERN Document Server

    Sarriguren, P

    2010-01-01

    Gamow-Teller strength distributions, beta-decay half-lives, and beta-delayed neutron emission are investigated in neutron-rich Zr and Mo isotopes within a deformed quasiparticle random-phase approximation. The approach is based on a self-consistent Skyrme Hartree-Fock mean field with pairing correlations and residual separable particle-hole and particle-particle forces. Comparison with recent measurements of half-lives stresses the important role that nuclear deformation plays in the description of beta-decay properties in this mass region.

  3. Neutrinoless Double Beta Decay

    CERN Document Server

    Päs, Heinrich

    2015-01-01

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

  4. Beta and muon decays

    International Nuclear Information System (INIS)

    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)

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

    CERN Document Server

    Barabash, A S

    2013-01-01

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

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

    CERN Document Server

    Barabash, A S

    2009-01-01

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

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

    CERN Document Server

    Barabash, A S

    2002-01-01

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

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

    CERN Document Server

    Barabash, A S

    2006-01-01

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

  9. Beta decay of 187Re and cosmochronology

    Science.gov (United States)

    Ashktorab, K.; Jänecke, J. W.; Becchetti, F. D.

    1993-06-01

    Uncertainties which limit the use of the 187-187Os isobaric pair as a cosmochronometer for the age of the galaxy and the universe include those of the partial half-lives of the continuum and bound-state decays of 187Re. While the total half-life of the decay is well established, the partial half-life for the continuum decay is uncertain, and several previous measurements are not compatible with each other. A high-temperature quartz proportional counter has been used in this work to remeasure the continuum decay of 187Re by introducing a metallo-organic rhenium compound into the counting gas. The measured beta end-point energy for the continuum decay of neutral 187Re to singly ionized 187Os of 2.70+/-0.09 keV agrees with earlier results. However, the present half-life measurement of (45+/-3) Gyr agrees within the quoted uncertainties only with the earlier measurement of Payne [Ph.D. thesis, University of Glasgow, 1965 (unpublished)] and Drever (private communication). The new half-life for the continuum decay and the total half-life of (43.5+/-1.3) Gyr, as reported by Linder et al. [Nature (London) 320, 246 (1986)] yield a branching ratio for the bound-state decay into discrete atomic states of (3+/-6)%. This is in agreement with the most recent calculated theoretical branching ratio of approximately 1%.

  10. Beta decay for pedestrians

    CERN Document Server

    Lipkin, Harry Jeannot

    1962-01-01

    The ""pedestrian approach"" was developed to describe some essentially simple experimental results and their theoretical implications in plain language. In this graduate-level text, Harry J. Lipkin presents simply, but without oversimplification, the aspects of beta decay that can be understood without reference to the formal theory; that is, the reactions that follow directly from conservation laws and elementary quantum mechanics.The pedestrian treatment is neither a substitute for a complete treatment nor a watered-down version.

  11. EXO the Enriched Xenon Observatory for Double Beta Decay

    CERN Document Server

    Wamba, K

    2002-01-01

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

  12. Nuclear Data Compilation for Beta Decay Isotope

    Science.gov (United States)

    Olmsted, Susan; Kelley, John; Sheu, Grace

    2015-10-01

    The Triangle Universities Nuclear Laboratory nuclear data group works with the Nuclear Structure and Decay Data network to compile and evaluate data for use in nuclear physics research and applied technologies. Teams of data evaluators search through the literature and examine the experimental values for various nuclear structure parameters. The present activity focused on reviewing all available literature to determine the most accurate half-life values for beta unstable isotopes in the A = 3-20 range. This analysis will eventually be folded into the ENSDF (Evaluated Nuclear Structure Data File). By surveying an accumulated compilation of reference articles, we gathered all of the experimental half-life values for the beta decay nuclides. We then used the Visual Averaging Library, a data evaluation software package, to find half-life values using several different averaging techniques. Ultimately, we found recommended half-life values for most of the mentioned beta decay isotopes, and updated web pages on the TUNL webpage to reflect these evaluations. To summarize, we compiled and evaluated literature reports on experimentally determined half-lives. Our findings have been used to update information given on the TUNL Nuclear Data Evaluation group website. This was an REU project with Triangle Universities Nuclear Laboratory.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-01-01

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

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

    CERN Document Server

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

    2013-01-01

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

  15. Spontaneous fission half-lives and their systematics

    International Nuclear Information System (INIS)

    Spontaneous fission is a phenomenon exhibited by heavy nuclei, which can be a major mode of decay of nuclei of elements heavier than thorium and can be a determining factor in their stability. For purposes of this paper, spontaneous fission will be considered a process in which a nucleus breaks up into two approximately equal parts. The emission of light nuclei or heavy ions such as 12C, 16O, or 32S will not be considered. This radioactive decay mode is often much smaller than the spontaneous fission decay mode, although this is not true in all cases. Barwick noted that this might indicate that the assumed half-life for spontaneous fission of some older experiments might be partially due to heavy fragment radioactivity. Other than taking note of this potential correction to spontaneous fission half-lives, this decay mode of heavy fragment radioactivity will be ignored. Excited states of some heavy nuclei may decay via spontaneous fission. These so-called fission isomers will not be discussed here. Electron capture (EC) or beta-delayed fission is a process in which prompt fission of a sufficiently excited daughter state occurs following population by EC or beta decay. The fission activity will appear to decay with the half-life of the parent and was earlier confused in some cases with SF. This process has been discussed in detail in a review and will not be considered in this paper

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

    International Nuclear Information System (INIS)

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

  17. Neutrino masses from double-beta decay calculations

    CERN Document Server

    Stoica, S

    2002-01-01

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

  18. Estimated α-decay half-lives of even-even Z=120 SHEs in the range of neutron number 172 ≤ N ≤ 186

    International Nuclear Information System (INIS)

    The super heavy elements formed by either way of cold fusion or hot fusion process, are primarily decay through alpha-particle emission and after successive emission of alpha-particles it undergoes to spontaneous fission. Alpha particle emission from super heavy elements is an important and unique part of all the decay process. Different theoretical approaches are using alpha-decay characteristics as a tool to investigate the nuclear structure information of the unstable nuclei such as the ground state energy, the ground state and isomeric state half-life, the nuclear spin and parity, the nuclear deformation, the clustering, the shell effects and the interaction between nuclei

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

    International Nuclear Information System (INIS)

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

  20. Beta decay studies of r-process nuclei at the National Superconducting Cyclotron Laboratory

    CERN Document Server

    Pereira, J; Arndt, O; Becerril, A; Elliot, T; Estrade, A; Galaviz, D; Hennrich, S; Hosmer, P; Kessler, R; Kratz, K L; Lorusso, G; Mantica, P F; Matos, M; Montes, F; Santi, P; Pfeiffer, B; Quinn, M; Schatz, H; Schertz, F; Schnorrenberger, L; Smith, E; Tomlin, B E; Walters, W; Wöhr, A

    2009-01-01

    The impact of nuclear physics on astrophysical r-process models is discussed, emphasizing the importance of beta-decay properties of neutron-rich nuclei. Several r-process motivated beta-decay experiments performed at the National Superconducting Cyclotron Laboratory are presented. The experiments include the measurement of beta-decay half-lives and neutron emission probabilities of nuclei in regions around Ni-78; Se-90; Zr-106 and Rh-120, as well as spectroscopic studies of Pd-120. A summary on the different experimental techniques employed, data analysis, results and impact on model calculations is presented.

  1. Double beta decay: present status

    OpenAIRE

    Barabash, A. S.

    2008-01-01

    The present status of double beta decay experiments (including the search for $2\\beta^{+}$, EC$\\beta^{+}$ and ECEC processes) are reviewed. The results of the most sensitive experiments are discussed. Average and recommended half-life values for two-neutrino double beta decay are presented. Conservative upper limits on effective Majorana neutrino mass and the coupling constant of the Majoron to the neutrino are established as $ < 0.75$ eV and $ < 1.9 \\cdot 10^{-4}$, respectively. Proposals fo...

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

    CERN Document Server

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

    2005-01-01

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

  3. Half-lives of neutron-rich Cd-130128

    Science.gov (United States)

    Dunlop, R.; Bildstein, V.; Dillmann, I.; Jungclaus, A.; Svensson, C. E.; Andreoiu, C.; Ball, G. C.; Bernier, N.; Bidaman, H.; Boubel, P.; Burbadge, C.; Caballero-Folch, R.; Dunlop, M. R.; Evitts, L. J.; Garcia, F.; Garnsworthy, A. B.; Garrett, P. E.; Hackman, G.; Hallam, S.; Henderson, J.; Ilyushkin, S.; Kisliuk, D.; Krücken, R.; Lassen, J.; Li, R.; MacConnachie, E.; MacLean, A. D.; McGee, E.; Moukaddam, M.; Olaizola, B.; Padilla-Rodal, E.; Park, J.; Paetkau, O.; Petrache, C. M.; Pore, J. L.; Radich, A. J.; Ruotsalainen, P.; Smallcombe, J.; Smith, J. K.; Tabor, S. L.; Teigelhöfer, A.; Turko, J.; Zidar, T.

    2016-06-01

    The β -decay half-lives of Cd-130128 have been measured with the newly commissioned GRIFFIN γ -ray spectrometer at the TRIUMF-ISAC facility. The time structures of the most intense γ rays emitted following the β decay were used to determine the half-lives of 128Cd and 130Cd to be T1 /2=246.2 (21 ) ms and T1 /2=126 (4 ) ms, respectively. The half-lives of the 3 /2+ and 11 /2- states of 129Cd were measured to be T1 /2(3 /2+) =157 (8 ) ms and T1 /2(11 /2-) =147 (3 ) ms. The half-lives of the Cd isotopes around the N =82 shell closure are an important ingredient in astrophysical simulations to derive the magnitude of the second r -process abundance peak in the A ˜130 region. Our new results are compared with recent literature values and theoretical calculations.

  4. Neutrinoless Double Beta Decay in Heavy Deformed Nuclei

    OpenAIRE

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

    1994-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-01-01

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

  6. β--decay half-lives for waiting p oint nuclei around N =82%等待点N =82附近核素β-衰变寿命的研究

    Institute of Scientific and Technical Information of China (English)

    陈泽; 张小平; 杨洪应; 郑强; 陈娜娜; 支启军

    2014-01-01

    Based on the exponential formula of β--decay half-lives for nuclei far from stable line, the half-lives of nuclei around N = 82 (R-process waiting point nuclei) are calculated. The results are compared with recent theoretical and experimental data. It is shown that compared with the complicated and time-consuming microscopic calculation, the exponential formula including the shell effect can give the results ofβ--decay half-lives for R-process waiting point nuclei quicker and better. The results can be used as reliable inputs for the network calculation for nuclei synthesis in cosmos.%利用提出的远离稳定线附近的原子核β-衰变寿命的指数规律理论计算公式,对N =82附近快中子过程中等待点核素的β-衰变寿命进行了理论计算,比较了所获得的计算结果与最新的理论结果和实验结果并加以讨论。研究表明,相对于理论复杂和计算时间长的微观理论计算而言,利用考虑壳效应的远离稳定线的原子核β-衰变寿命指数规律理论计算公式能较快且准确地得出快中子俘获过程(R过程)等待点核素的β-衰变寿命。这能为R过程核素合成网络计算研究提供有效可靠的重要物理输入,并对今后天体中核素的合成研究具有重要意义。

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

    Energy Technology Data Exchange (ETDEWEB)

    Brunner, Thomas

    2011-01-18

    The presented work describes the implementation of a new technique to measure electron-capture (EC) branching ratios (BRs) of intermediate nuclei in {beta}{beta} decays. This technique has been developed at TRIUMF in Vancouver, Canada. It facilitates one of TRIUMF's Ion Traps for Atomic and Nuclear science (TITAN), the Electron Beam Ion Trap (EBIT) that is used as a spectroscopy Penning trap. Radioactive ions, produced at the radioactive isotope facility ISAC, are injected and stored in the spectroscopy Penning trap while their decays are observed. A key feature of this technique is the use of a strong magnetic field, required for trapping. It radially confines electrons from {beta} decays along the trap axis while X-rays, following an EC, are emitted isotropically. This provides spatial separation of X-ray and {beta} detection with almost no {beta}-induced background at the X-ray detector, allowing weak EC branches to be measured. Furthermore, the combination of several traps allows one to isobarically clean the sample prior to the in-trap decay spectroscopy measurement. This technique has been developed to measure ECBRs of transition nuclei in {beta}{beta} decays. Detailed knowledge of these electron capture branches is crucial for a better understanding of the underlying nuclear physics in {beta}{beta} decays. These branches are typically of the order of 10{sup -5} and therefore difficult to measure. Conventional measurements suffer from isobaric contamination and a dominating {beta} background at theX-ray detector. Additionally, X-rays are attenuated by the material where the radioactive sample is implanted. To overcome these limitations, the technique of in-trap decay spectroscopy has been developed. In this work, the EBIT was connected to the TITAN beam line and has been commissioned. Using the developed beam diagnostics, ions were injected into the Penning trap and systematic studies on injection and storage optimization were performed. Furthermore, Ge

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

    International Nuclear Information System (INIS)

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

  9. Predicting Neutrinoless Double Beta Decay

    CERN Document Server

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

    2005-01-01

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

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

    CERN Document Server

    Barabash, A S

    2010-01-01

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

  11. Neutrinoless Double Beta Decay Experiments

    OpenAIRE

    Zuber, K.

    2014-01-01

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

  12. Beta decay of 31Ar

    International Nuclear Information System (INIS)

    A complete study of 31Ar beta decay has been made by high-resolution charged-particle and gamma-ray spectroscopy. Beta-delayed radiation was detected by an array of three charged-particle detectors and a large-volume germanium detector. Fifteen new energy levels were discovered in 31Cl. The beta-strength distribution, measured to 14.5 MeV, is compared with a shell-model calculation in the full sd space. The quenching of the Gamow-Teller strength and the isospin impurity of the IAS in 31Cl are discussed. (orig.)

  13. Experiments on double beta decay

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-11-01

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

  14. Determination of the ratio of axial-vector-to-vector weak coupling constants for beta decay of triton

    International Nuclear Information System (INIS)

    Data on the chemical shifts of half-lives for atomic and molecular tritium were used to determine the ratio of axial-vector-to-vector weak coupling constants for beta decay of triton (GA/GV)t = -1.2646 ± 0.0035

  15. Constraining neutrinoless double beta decay

    International Nuclear Information System (INIS)

    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.

  16. Weak decays and double beta decay

    International Nuclear Information System (INIS)

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

  17. Impact of tensor force on \\beta-decay of magic and semi-magic nuclei

    OpenAIRE

    Minato, F.; Bai, C.L.

    2013-01-01

    Effect of the tensor force on $\\beta$?-decay is studied in the framework of the proton-neutron random-phase-approximation (RPA) with the Skyrme force. The investigation is performed for even-even semi-magic and magic nuclei, $^{34}$Si, $^{68}$, $^{78}$Ni and $^{132}$Sn. The tensor correlation induces strong impact on low-lying Gamow-Teller state. In particular, it improves the ?$\\beta$-decay half-lives. $Q$ and $ft$ values are also investigated and compared with experimental data.

  18. Evolution of the nuclear structure approaching $^{78}$Ni: $\\beta$ decay of $^{74-78}$Cu

    CERN Document Server

    Van Roosbroeck, J; De Maesschalck, A; De Witte, H; Fedorov, D; Fedosseev, V; Franchoo, S; Fynbo, H O U; Georg, U; Górska, M; Heyde, Kris L G; Huyse, M; Jonsson, O; Köster, U; Kruglov, K; Mishin, V I; Müller, W F; Pauwels, D; Smirnova, N A; Thomas, J C; Van Duppen, P; Van de Vel, K; Weissman, L

    2005-01-01

    A beta -decay study of the even mass /sup 74,76,78/Cu isotopes toward levels in /sup 74,76,78/Zn was performed at the ISOLDE mass separator. The copper isotopes were produced in proton- or neutron- induced fission reactions on /sup 238/U, laser ionized, mass separated, and sent to a beta - gamma detection system. Half-lives, decay schemes, and possible spin configurations were obtained for the copper isotopes. The results are compared with calculations using schematic forces as well as large-scale shell-model calculations with realistic forces.

  19. 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

  20. Beta decay of the exotic $T_z$ = -2 nuclei $^{48}$Fe, $^{52}$Ni and $^{56}$Zn

    OpenAIRE

    Orrigo, S. E. A.; Rubio, B.; Fujita, Y; Gelletly, W.; Agramunt, J.; Algora, A.; Ascher, P; Bilgier, B.; Blank, B.; Cáceres, L.; Cakirli, R. B.; Ganioğlu, E.; Gerbaux, M.; Giovinazzo, J.; Grévy, S.

    2016-01-01

    The results of a study of the beta decays of three proton-rich nuclei with $T_z=\\text{-}2$, namely $^{48}$Fe, $^{52}$Ni and $^{56}$Zn, produced in an experiment carried out at GANIL, are reported. In all three cases we have extracted the half-lives and the total $\\beta$-delayed proton emission branching ratios. We have measured the individual $\\beta$-delayed protons and $\\beta$-delayed $\\gamma$ rays and the branching ratios of the corresponding levels. Decay schemes have been determined for t...

  1. Half-lives of heavy nuclei within simple phenomenological models

    International Nuclear Information System (INIS)

    We have studied the competition between alpha decay and the spontaneous fission processes in heavy isotopes. The half-lives of nuclei were calculated using phenomenological formulae, based on Świ atecki's, idea (1955 Phys. Rev. 100 937) for spontaneous fission and a Gamow-like model (2013 Phys. Rev. C 87 024308) for alpha decay. Elements with the atomic number 90⩽Z⩽103 were considered

  2. The Effect of Cancellation in Neutrinoless Double Beta Decay

    CERN Document Server

    Pascoli, Silvia; Wong, Steven

    2013-01-01

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

  3. Bound beta-decay: BOB

    International Nuclear Information System (INIS)

    For many years exotic decay modes of the neutron have been investigated as possible doorways to the exploration of new physics. The bound beta-decay (BOB) of the neutron into a hydrogen atom and an anti-neutrino offers a very elegant method to study neutrino helicities. However, this rare decay has not yet been observed for the free neutron, owing to the challenge of measuring a decay involving only electrically neutral particles and with an estimated branching ratio of only a few 106 of the three-body decay mode. During the past few years scientists from the TUM E18 Group have developed a novel experimental scheme which addresses all necessary problems associated with the observation of this two-body neutron decay in a very coherent way. The BOB experiment shall be installed at a tangential beam tube of a powerful research reactor such as the SR6 at the FRMII in Garching or H6-H7 beam tube at ILL. This talk will provide insights and ideas on how such an experiment is to be performed.

  4. Pion beta decay at PILAC

    International Nuclear Information System (INIS)

    The proposal to build PILAC presents the possibility of making an improved measurement of the pion beta decay rate. The rate for the decay π+ → π0e+νe is predicted by the Standard Model (SM) to be R(π+ → π0e+νe) = 0.3999 ± 0.0005 s-1. The best experimental number, from LAMPF Experiment 32, using in-flight decays, is R(π+ → π0e+νe) = 0.394 ± 0.0015 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. Thus 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. 23 refs., 2 figs., 2 tabs

  5. Local and global effects of beta decays on r-process

    CERN Document Server

    Caballero, O L; Borzov, I N; Langanke, K; Martinez-Pinedo, G

    2014-01-01

    Nuclear beta decay rates are an essential ingredient in simulations of the astrophysical r-process. Most of these rates still rely on theoretical modeling. However, modern radioactive ion-beam facilities have allowed to measure beta half lives of some nuclei on or close to the r-process path. These data indicate that r-process half lives are in general shorter than anticipated in the standard theoretical predictions based on the Finite Range Droplet Model (FRDM). The data have also served as important constraints for improved predictions of half lives based on continuum QRPA calculations on top of the energy-density functional theory. Although these calculations are yet limited to spherical nuclei, they include the important r-process waiting point nuclei close to and at the neutron magic numbers $N=50, 82$ and 126. We have studied the impact of these new experimental and theoretical half lives on r-process nucleosynthesis within the two astrophysical sites currently favored for the r process: the neutrino-dr...

  6. Results on $\\beta\\beta$ decay with emission of two neutrinos or Majorons in $^{76}$Ge from GERDA Phase I

    CERN Document Server

    Agostini, M; Bakalyarov, A M; Balata, M; Barabanov, I; Barros, N; 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; di Vacri, A; Domula, A; Doroshkevich, E; Egorov, V; Falkenstein, R; Fedorova, O; Freund, K; Frodyma, N; Gangapshev, A; Garfagnini, A; Grabmayr, P; Gurentsov, V; Gusev, K; Hegai, A; Heisel, M; Hemmer, S; Heusser, G; Hofmann, W; Hult, M; Inzhechik, L V; Csáthy, J Janicskó; 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; Medinaceli, E; Misiaszek, M; Moseev, P; Nemchenok, I; Palioselitis, D; Panas, K; Pandola, L; Pelczar, K; Pullia, A; Riboldi, S; Rumyantseva, N; Sada, C; Salathe, M; Schmitt, C; Schreiner, J; Schulz, O; Schwingenheuer, B; Schönert, S; Selivanenko, O; Shirchenko, M; Simgen, H; Smolnikov, A; Stanco, L; Stepaniuk, M; Ur, C A; Vanhoefer, L; Vasenko, A A; Veresnikova, A; von Sturm, K; Wagner, V; Walter, M; Wegmann, A; Wester, T; Wilsenach, H; Wojcik, M; Yanovich, E; Zavarise, P; Zhitnikov, I; Zhukov, S V; Zinatulina, D; Zuber, K; Zuzel, G

    2015-01-01

    A search for neutrinoless $\\beta\\beta$ decay processes accompanied with Majoron emission has been performed using data collected during Phase I of the GERmanium Detector Array (GERDA) experiment at the Laboratori Nazionali del Gran Sasso of INFN (Italy). Processes with spectral indices n = 1, 2, 3, 7 were searched for. No signals were found and lower limits of the order of 10$^{23}$ yr on their half-lives were derived, yielding substantially improved results compared to previous experiments with $^{76}$Ge. A new result for the half-life of the neutrino-accompanied $\\beta\\beta$ decay of $^{76}$Ge with significantly reduced uncertainties is also given, resulting in $T^{2\

  7. 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.

  8. Experiments on double beta decay

    International Nuclear Information System (INIS)

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

  9. Statistical analysis of beta decays and the effective value of g_A in the pnQRPA framework

    CERN Document Server

    Deppisch, Frank F

    2016-01-01

    We perform a Markov Chain Monte Carlo (MCMC) statistical analysis of a number of measured ground-state-to-ground-state single $\\beta^+$/electron-capture and $\\beta^-$ decays in the nuclear mass range A = 62 - 142. The corresponding experimental comparative half-lives (log ft values) are compared with the theoretical ones obtained by the use of the proton-neutron quasiparticle random-phase approximation (pnQRPA) with G-matrix based effective interactions. The MCMC analysis is performed separately for 47 isobaric triplets and 28 more extended isobaric chains of nuclei to extract values and uncertainties for the effective axial-vector coupling constant g_A in nuclear-structure calculations performed in the pnQRPA framework. As far as available, measured half-lives for two-neutrino double beta-minus decays occurring in the studied isobaric chains are analyzed as well.

  10. Theoretical aspects of double beta decay

    International Nuclear Information System (INIS)

    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

  11. 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.

  12. Double beta decay of 100Mo

    International Nuclear Information System (INIS)

    Using a liquid argon ionization chamber, the 2νββ decay of 100 Mo was detected with its half-life of (7.5 ± 1.1(stat.) ± 1.5(syst.)) · 1018 y. The limits on half-lives for the 0ν and 0νχ0 decays of 100Mo were estimated as 9.3(5.0) · 1021 and 4.3(2.7) · 1020 y respectively at 68 % (90%) C.L. Available world data for the 2νββ decay of 100Mo lead to the average 'world' value of the half-life, T1/2 = (8.0 ± 0.7) · 1018 y, which corresponds to the nuclear matrix element, MGT = 0.118 ± 0.005

  13. Broad resonances and beta-decay

    DEFF Research Database (Denmark)

    Riisager, K.; Fynbo, H. O. U.; Hyldegaard, S.;

    2015-01-01

    Beta-decay into broad resonances gives a distorted lineshape in the observed energy spectrum. Part of the distortion arises from the phase space factor, but we show that the beta-decay matrix element may also contribute. Based on a schematic model for p-wave continuum neutron states it is argued...

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

    CERN Document Server

    Barabash, A S

    2015-01-01

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

  15. {beta}-decay rates of r-process nuclei in the relativistic quasiparticle random phase approximation

    Energy Technology Data Exchange (ETDEWEB)

    Niksic, T.; Marketin, T.; Vretenar, D. [Zagreb Univ. (Croatia). Faculty of Science, Physics Dept.; Paar, N. [Technische Univ. Darmstadt (Germany). Inst. fuer Kernphysik; Ring, P. [Technische Univ. Muenchen, Garching (Germany). Physik-Department

    2004-12-08

    The fully consistent relativistic proton-neutron quasiparticle random phase approximation (PN-RQRPA) is employed in the calculation of {beta}-decay half-lives of neutron-rich nuclei in the N{approx}50 and N{approx}82 regions. A new density-dependent effective interaction, with an enhanced value of the nucleon effective mass, is used in relativistic Hartree-Bogolyubov calculation of nuclear ground states and in the particle-hole channel of the PN-RQRPA. The finite range Gogny D1S interaction is employed in the T=1 pairing channel, and the model also includes a proton-neutron particle-particle interaction. The theoretical half-lives reproduce the experimental data for the Fe, Zn, Cd, and Te isotopic chains, but overestimate the lifetimes of Ni isotopes and predict a stable {sup 132}Sn. (orig.)

  16. Failure of the gross theory of beta decay in neutron deficient nuclei

    International Nuclear Information System (INIS)

    The neutron deficient isotopes 117-121Xe, 117-124Cs, and 122-124Ba were produced by a beam of 28Si from the LBNL SuperHILAC on a target of natMo. The isotopes were mass separated and their beta decay schemes were measured with a Total Absorption Spectrometer (TAS). The beta strengths derived from these data decreased dramatically to levels above ≈1 MeV for the even-even decays; 3–4 MeV for even-Z, odd-N decays; 4–5 MeV for the odd-Z, even-N decays; and 7–8 MeV for the odd-Z, odd-N decays. The decreasing strength to higher excitation energies in the daughters contradicts the predictions of the Gross Theory of Beta Decay. The integrated beta strengths are instead found to be consistent with shell model predictions where the single-particle beta strengths are divided amoung many low-lying levels. The experimental beta strengths determined here have been used calculate the half-lives of 143 neutron deficient nuclei with Z=51–64 to a precision of 20% with respect to the measured values

  17. Beta decay of highly charged ions

    International Nuclear Information System (INIS)

    Ion storage rings and ion traps provide the very first opportunity to address nuclear beta decay under conditions prevailing in hot stellar plasmas during nucleosynthesis, i.e. at high atomic charge states. Experiments are summarized that were performed in this field during the last decade at the ion storage-cooler ring ESR in Darmstadt. Special emphasis is given to the first observation of bound-state beta decay, where the created electron remains bound in an inner orbital of the daughter atom. The impact of this specific 'stellar' decay mode for s-process nucleosynthesis as well as for nuclear 'eon clocks' is outlined. Finally, a new technique, single-ion decay spectroscopy, is presented, where one observes two-body beta decay characteristics (i.e. orbital electron capture or bound-state beta decay) of highly charged, single ions for well-defined nuclear and atomic quantum states of both the mother - and the daughter - ion.

  18. First forbidden beta decay in light nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Millener, D.J.; Warburton, E.K.

    1984-01-01

    Beta decay matrix elements for the operators sigma dot del and sigma dot r are calculated for eight J/sup +/ ..-->.. J/sup -/ or J/sup -/ ..-->.. J/sup +/ beta transitions. Results using harmonic oscillator wave functions differ markedly from those using more realistic Woods-Saxon wave functions. A substantial contribution to the sigma dot del matrix elements from pion exchange currents is required to reproduce the experimental beta decay rates. 15 references.

  19. First forbidden beta decay in light nuclei

    International Nuclear Information System (INIS)

    Beta decay matrix elements for the operators sigma dot del and sigma dot r are calculated for eight J+ → J- or J- → J+ beta transitions. Results using harmonic oscillator wave functions differ markedly from those using more realistic Woods-Saxon wave functions. A substantial contribution to the sigma dot del matrix elements from pion exchange currents is required to reproduce the experimental beta decay rates. 15 references

  20. Evaluation method of nuclear data: half-lives, gamma-ray intensities etc

    Energy Technology Data Exchange (ETDEWEB)

    Yoshizawa, Yasukazu; Miyatake, Osamu; Toyama, Masao

    1998-03-01

    The evaluation method has been studied. The basic problem is how to estimate and treat the systematic error. Nuclear decay data were evaluated. Eight practical examples of half-lives are shown in this report. (author)

  1. Double beta decay: A theoretical overview

    Energy Technology Data Exchange (ETDEWEB)

    Rosen, S.P.

    1988-01-01

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

  2. Theoretical half-life for beta decay of {sup 96}Zr

    Energy Technology Data Exchange (ETDEWEB)

    Heiskanen, H; Mustonen, M T; Suhonen, J [Department of Physics, University of Jyvaeskylae, PO Box 35, FIN-40351, Jyvaeskylae (Finland)

    2007-05-15

    Highly forbidden {beta}{sup -} decay of the 0{sup +} ground state of {sup 96}Zr is studied. Partial half-lives to the lowest 6{sup +}, 5{sup +} and 4{sup +} states of {sup 96}Nb have been computed using the proton-neutron quasiparticle random-phase approximation (pnQRPA) with realistic two-body interactions in a large single-particle space. We find that the decay is dominated by the unique fourth-forbidden transition to the 5{sup +} state with the half-life 2.4 x 10{sup 20} y. This half-life is an order of magnitude longer than the one measured for the double beta decay of {sup 96}Zr.

  3. Particle-vibration coupling effect on the $\\beta$-decay of magic nuclei

    CERN Document Server

    Niu, Yifei; Colo, Gianluca; Vigezzi, Enrico

    2015-01-01

    Nuclear $\\beta$-decay in magic nuclei is investigated, taking into account the coupling between particle and collective vibrations,on top of self-consistent random phase approximation calculations based on Skyrme density functionals. The low-lying Gamow-Teller strength is shifted downwards and at times becomes fragmented; as a consequence, the $\\beta$-decay half-lives are reduced due to the increase of the phase space available for the decay. In some cases, this leads to a very good agreement between theoretical and experimental lifetimes: this happens, in particular, in the case of the Skyrme force SkM*, that can also reproduce the line shape of the high energy Gamow-Teller resonance as it was previously shown.

  4. The search for neutrinoless double beta decay

    CERN Document Server

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

    2011-01-01

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

  5. Neutron bound {beta}- decay- BOB

    Energy Technology Data Exchange (ETDEWEB)

    Gabriel, M.; Berger, M.; Emmerich, R.; Faestermann, T.; Gutsmiedl, E.; Hartmann, F.J.; Paul, S.; Ruschel, S.; Schoen, J.; Schott, W.; Schubert, U.; Trautner, A. [Physik-Department, TUM, 85748 Garching (Germany); Engels, R. [Institut fuer Kernphysik, Forschungszentrum Juelich, 52425 Juelich (Germany); Fierlinger, P. [Excellence Cluster Universe, TUM, 85748 Garching (Germany); Hertenberger, R. [Sektion Physik, LMU, 85748 Garching (Germany); Roehrmoser, R. [FRM2, TUM, 85748 Garching (Germany); Udem, T. [Max-Planck-Institut fuer Quantenphysik, 85748 Garching (Germany)

    2011-07-01

    The bound neutron {beta}-decay(BOB) into a hydrogen atom and an electron antineutrino is investigated.The hyper-fine-state population of the monoenergetic hydrogen atoms (326.3 eV) yields the neutrino left-handed-ness or a possible right-handed admixture and possible small scalar and tensor contributions to the weak force. Preexperiments to measure the BOB H(2s) atoms have been done or are being set up using ionizer and RF discharge proton sources, a Wien filter, Cs and Ar cells, a spin filter, electric counter and accelerating fields, a double focusing magnet and a solar blind PM for the Lyman-{alpha} photons. In a first experiment, the charge exchange of the H(2s) atoms into H{sup -}, offering a selective method to discriminate these states against background, is investigated. In a second step the number of background H(2s) resulting from protons interacting with the walls of the experimental setup are determined. For this a quenching E field and a solar blind PM are used.

  6. Falsifying Baryogenesis with Neutrinoless Double Beta Decay

    CERN Document Server

    Graf, Lukas

    2016-01-01

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

  7. Review of modern double beta decay experiments

    Science.gov (United States)

    Barabash, A. S.

    2015-10-01

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

  8. Fission barriers and half-lives

    International Nuclear Information System (INIS)

    The authors briefly review the development of theoretical models for the calculation of fission barriers and half-lives. They focus on how results of actual calculations in a unified macroscopic-microscopic approach provide an interpretation of the mechanisms behind some of the large number of phenomena observed in fission. As instructive examples they choose studies of the rapidly varying fission properties of elements at the end of the periodic system

  9. Systematic study of α half-lives of superheavy nuclei

    International Nuclear Information System (INIS)

    Two different descriptions of the α-decay process, namely, the shell model rate theory and phenomenological description are emphasized to investigate the α-decay properties of superheavy nuclei (SHN). These descriptions are shortly presented and illustrated by their results. Special attention is given to the shell structure and resonance scattering effects due to which they exist and decay. A first systematics of α-decay properties of SHN was per- formed by studying the half-life vs. energy correlations in terms of atomic number and mass number. Such a systematics shows that the transitions between even-even nuclei are favored, while all other transitions with odd nucleons are prohibited. The accuracy of experimental and calculated α-half-lives is illustrated by the systematics of these results. (authors)

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

    CERN Document Server

    Lehnert, Bjoern

    2011-01-01

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

  11. Review of modern double beta decay experiments

    International Nuclear Information System (INIS)

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

  12. Neutrino potential for neutrinoless double beta decay

    CERN Document Server

    Iwata, Yoritaka

    2016-01-01

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

  13. Review of modern double beta decay experiments

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-10-28

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

  14. Searches for neutrinoless double beta decay

    Science.gov (United States)

    Schwingenheuer, Bernhard

    2012-07-01

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

  15. Searches for neutrinoless double beta decay

    CERN Document Server

    Schwingenheuer, B

    2012-01-01

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

  16. Nuclear physics issues in double beta decay

    International Nuclear Information System (INIS)

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

  17. Total half-lives for selected nuclides

    International Nuclear Information System (INIS)

    Measurements of the half-lives of 3H, 10Be, 14C, 26Al, 40K, 39Ar, 53Mn, 87Rb, 92Nb, 129I, 138La, 147Sm, 176Lu, 174Hf, 180Ta, 187Re, 186Os, 190Pt, 204Pb, 210Pb, 210Po, 222Rn, 224Th, 226Ra, 227Ac, 228Ra, 228Th, 230Th, 232Th, 231Pa have been compiled and evaluated. The effect of the 14C half-life value on carbon dating ages is discussed as well as the stability of 204Pb. 237 refs., 30 tabs

  18. Effects of deformation on the beta-decay patterns of light even-even and odd-mass Hg and Pt isotopes

    CERN Document Server

    Boillos, J M

    2015-01-01

    Bulk and decay properties, including deformation energy curves, charge mean square radii, Gamow-Teller (GT) strength distributions, and beta-decay half-lives, are studied in neutron-deficient even-even and odd-A Hg and Pt isotopes. The nuclear structure is described microscopically from deformed quasiparticle random-phase approximation calculations with residual interactions in both particle-hole and particle-particle channels, performed on top of a self-consistent deformed quasiparticle Skyrme Hartree-Fock basis. The observed sensitivity of the, not yet measured, GT strength distributions to deformation is proposed as an additional complementary signature of the nuclear shape. The $\\beta$-decay half-lives resulting from these distributions are compared to experiment to demonstrate the ability of the method.

  19. Recent double beta decay results

    Energy Technology Data Exchange (ETDEWEB)

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

    1992-02-01

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

  20. Charge exchange nuclear excitations and beta decay within the self consistent deformed QRPA

    International Nuclear Information System (INIS)

    Spin-isospin nuclear excitations play a crucial role in astrophysics where they govern beta-decay, electron and neutrino capture processes, hence stellar evolution and nucleosynthesis. These excitations are studied here within the fully self-consistent proton-neutron quasiparticle random-phase approximation using the finite-range Gogny interaction. Axially symmetric deformations are consistently taken into account, both in the description of the ground states and spin-isospin excitations. We focus in particular on the Gamow-Teller excitations. A comparison of the predicted strength distributions to the existing experimental data is presented and the role of nuclear deformation analyzed. The Gamow-Teller strength is used to estimate the beta-decay half-life of nuclei for which experimental data exist. A satisfactory agreement with experimental half-lives is found and justifies the additional study of the exotic neutron-rich N=82, 126 and 184 isotonic chains of relevance for the r-process nucleosynthesis. We also show the comparison between our theoretical predictions and the experimental half-lives for the much studied isotopic chains of Kr, Sr, Zr and Mo which are strongly deformed. (author)

  1. Half-lives and kinetic energies for the spontaneously emitted heavy clusters from nuclei

    International Nuclear Information System (INIS)

    The partial half-lives, branching ratios relative to the alpha decay, kinetic energies and Q-values for the most probable spontaneously emitted heavy ions from 766 nuclides with z=47-106 and total half-lives longer than 1 μs, are estimated by using the analytical supersymmetric fission model, a semiempirical formula for α-decay life-times which are not measured, and the Wapstra-Audi new mass tables. Even the so-called 'stable' nuclides with Z>40 are meta-stable relative to the new decay modes. The experimental evidences are briefly reviewed. (orig.)

  2. Neutrinoless double beta decay from lattice QCD

    CERN Document Server

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

    2016-01-01

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

  3. Double-Beta Decay at TUNL

    Science.gov (United States)

    Kidd, Mary

    2007-10-01

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

  4. Nuclear beta decay after Les Houches

    International Nuclear Information System (INIS)

    Wilkinson's 1977 Les Houches lectures summarized in detail how nuclear beta decay can be used to investigate fundamental nuclear phenomena and the achievements of this utilization up to that time. In this short talk the subsequent activity is briefly summarized and one area of high activity, namely first-forbidden beta decay, is singled out for more lengthy discussion. Specifically, the subject of interest is the very large meson exchange contribution to the time-like component of the axial current and the efforts to isolate this enhancement by means of careful shell-model calculations. 19 refs., 4 figs., 2 tabs

  5. Why search for double beta decay?

    International Nuclear Information System (INIS)

    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

  6. Helicity and nuclear $\\beta$ decay correlations

    CERN Document Server

    Hong, Ran; García, Alejandro

    2016-01-01

    We present simple derivations of nuclear $\\beta$-decay correlations with an emphasis on the special role of helicity. This provides a good opportunity to teach students about helicity and chirality in particle physics through exercises using simple aspects of quantum mechanics. In addition, this paper serves as an introduction to nuclear $\\beta$-decay correlations from both a theoretical and experimental vantage. This article can be used to introduce students to ongoing experiments searching for hints of new physics in the low-energy precision frontier.

  7. Tables of double beta decay data

    International Nuclear Information System (INIS)

    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

  8. 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.)

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

    Science.gov (United States)

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

    2015-12-01

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

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

    International Nuclear Information System (INIS)

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

  11. 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.

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

    International Nuclear Information System (INIS)

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

  13. Symmetry violations in nuclear and neutron $\\beta$ decay

    CERN Document Server

    Vos, K K; Timmermans, R G E

    2015-01-01

    The role of $\\beta$ decay as a low-energy probe of physics beyond the Standard Model is reviewed. Traditional searches for deviations from the Standard Model structure of the weak interaction in $\\beta$ decay are discussed in the light of constraints from the LHC and the neutrino mass. Limits on the violation of time-reversal symmetry in $\\beta$ decay are compared to the strong constraints from electric dipole moments. Novel searches for Lorentz symmetry breaking in the weak interaction in $\\beta$ decay are also included, where we discuss the unique sensitivity of $\\beta$ decay to test Lorentz invariance. We end with a roadmap for future $\\beta$-decay experiments.

  14. Double-beta decay in gauge theories

    International Nuclear Information System (INIS)

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

  15. Semiconductor detectors and double beta decay

    International Nuclear Information System (INIS)

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

  16. Lepton nonconservation and double beta decay

    International Nuclear Information System (INIS)

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

  17. Long term prospects for double beta decay

    OpenAIRE

    Zuber, K.

    2010-01-01

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

  18. Beyond low beta-decay Q values

    Science.gov (United States)

    Mustonen, M. T.; Suhonen, J.

    2010-11-01

    Beta decays with low Q values can be utilized in the quest to determine the neutrino mass scale. This is being realized in two experiments, KATRIN and MARE, using tritium and 187Re, respectively. The beta-decay of 187Re had the lowest known Q value until 2005, when the beta decay of 115In to the first excited state of 115Sn was discovered in Gran Sasso underground laboratory. Last year two independent ion trap measurements confirmed that this decay breaks the former record by an order of magnitude. Our theoretical study on this tiny decay channel complemented the experimental effort by the JYFLTRAP group in Finland and HADES underground laboratory in Belgium. A significant discrepancy between the experimental and theoretical results was found. This might be explained by various atomic contributions known to grow larger as the Q value decreases. However, the traditional recipes for taking these effects into account break down on this new ultra-low Q value regime, providing new challenges for theorists on the borderline between nuclear and atomic physics.

  19. Half-lives of heavy nuclei through α tagging

    International Nuclear Information System (INIS)

    In this paper we describe a recent analysis of an experiment in which nuclei with N>126 were populated by the relativistic fragmentation of a 238U beam at 1 GeV/u on a 2.5 g/cm2 Be target. The fragmentation products were transported and analyzed by the Fragment Separator of the GSI laboratory, and then brought to rest in a Si stopper consisting of 9 Double Sided Silicon Strip Detectors, surrounded by the RISING γ-detector array. α and β correlations have been exploited to extract half-lives and delayed spectra in the region of heavy Pb-Bi-Po isotopes. Despite the presence of many contributing decay chains, we could extract and confirm the lifetimes of many nuclei

  20. Beta decay rates for nuclei with 115 < < 140 for r-process nucleosynthesis

    Indian Academy of Sciences (India)

    Kamales Kar; Soumya Chakravarti; V R Manfredi

    2006-08-01

    For r-process nucleosynthesis the -decay rates for a number of neutron-rich intermediate heavy nuclei are calculated. The model for the -strength function is able to reproduce the observed half-lives quite well.

  1. Measurement of the beta asymmetry in neutron beta decay

    International Nuclear Information System (INIS)

    Neutron beta decay is the simplest semi-leptonic weak decay and described accurately by the standard model using the first CKM-matrix element and the ratio of vector and axial vector couplings, λ. With more than a dozen observables it is a sensitive probe for investigating the nature of weak interaction and to search for physics beyond the standard model. In the past, measuring the beta asymmetry A in polarized neutron decay has been the most precise way of determining λ and nowadays it allows - together with other observables - to derive limits on non-standard model interactions, such as scalar and tensor couplings. The neutron decay spectrometer Perkeo III was installed at the PF1B cold neutron beam site at the Institut Laue-Langevin to measure the beta asymmetry. By using a pulsed beam combined with an improved detector design a significant reduction of several systematic uncertainties has been achieved compared to the predecessor, Perkeo II. In this talk recent results of the measurements with Perkeo III will be presented. In particular, we show the energy distribution of the electrons together with the calibration tools for the detectors.

  2. Double beta decay and neutrino mass models

    CERN Document Server

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

    2015-01-01

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

  3. Isospin mixing and beta decay

    International Nuclear Information System (INIS)

    In this work, we are interested in the breaking of the isospin symmetry in the N ≅ Z nuclei and in its effect on the matrix element of super-allowed 0+ → 0+ Fermi β transitions in the case of the β+ decay of the 50Mn. Within the framework of the Highly Truncated Diagonalization microscopic Approach (HTDA), dedicated to the description of correlations beyond the mean field and conserving explicitly the particle number, we have studied (in particular) the role played by pairing correlations in the breaking mechanisms of this symmetry in the ground state of N ≅ Z nuclei. A sensitivity study of the isospin mixing, as a function of the strength of the residual interaction describing the pairing correlations in HTDA, has been carried out and an interpretation of the mechanisms at work has been proposed in terms of an approximation developed in this work. This study has pointed out the complexity of a good treatment of the isospin symmetry, in the description of the breaking sources as well as in the reduction of model biases. We have also paid attention to the necessity of a very fine description of the correlated wave functions in such a problem. More precisely, we have obtained a value for the isospin mixing correction δC to the Fermi transition matrix element of (0.2 ± 0.1)%. This value has been compared to those obtained in other approaches. Taking account of the neglected effects in our work, our value of δC is expected to be a lower bound. (author)

  4. Exchange effects in double beta decay

    International Nuclear Information System (INIS)

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

  5. Double-beta decay in deformed nuclei

    International Nuclear Information System (INIS)

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

  6. JUNO and neutrinoless double beta decay

    Science.gov (United States)

    Ge, Shao-Feng; Rodejohann, Werner

    2015-11-01

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

  7. JUNO and Neutrinoless Double Beta Decay

    CERN Document Server

    Ge, Shao-Feng

    2015-01-01

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

  8. Importance of neutrinoless double beta decay

    CERN Document Server

    Sarkar, Utpal

    2007-01-01

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

  9. Search for Neutrinoless Double-Beta Decay

    CERN Document Server

    Tornow, Werner

    2014-01-01

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

  10. Applications of TAGS data in beta decay energies and decay heat calculations

    OpenAIRE

    Pham, N. S.; 片倉 純一

    2007-01-01

    The recent data of beta-decay intensity measured by using the total absorption gamma-ray spectrometer (TAGS), for several fission products (FP), has been applied for calculations of the average energies and spectra, and decay heat summations. The calculations were performed based on the Gross theory of beta decay, in which the beta strength functions were experimentally derived from TAGS data. The deviations of decay heat power predictions from the original decay data of JENDL Decay Data File...

  11. JUNO and Neutrinoless Double Beta Decay

    OpenAIRE

    Ge, Shao-Feng; Rodejohann, Werner

    2015-01-01

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

  12. NEUTRINOLESS DOUBLE BETA DECAY: AN EXTREME CHALLENGE

    OpenAIRE

    Fernando Ferroni

    2013-01-01

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

  13. Simulation in double-beta decay experiments

    International Nuclear Information System (INIS)

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

  14. Weak interaction studies from nuclear beta decay

    International Nuclear Information System (INIS)

    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 Os189 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 B12 and N12 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.)

  15. First-forbidden transitions and stellar $\\beta$-decay rates of Zn and Ge isotopes

    CERN Document Server

    Nabi, Jameel-Un; Stoica, Sabin; Iftikhar, Zafar

    2016-01-01

    First-forbidden (FF) charge-changing transitions become relatively important for nuclei as their proton number increases. This is because the strength of allowed Gamow-Teller (GT) transitions decreases with increasing Z. The FF transitions play an important role in reducing the half-lives as against those calculated from taking the GT transitions alone into account. In this paper we calculate allowed GT as well as $0^{+} \\rightarrow 0^{-}$ and $0^{+} \\rightarrow 2^{-}$ transitions for neutron-rich Zn and Ge isotopes. Two different pn-QRPA models were used with a schematic separable interaction to calculate GT and FF transitions. Half-lives calculated after inclusion of FF transitions were in excellent agreement with the experimental data. Our calculations were also compared to previous QRPA calculations and were found to be in better agreement with measured data. Stellar $\\beta$-decay rates were calculated for these nuclei including allowed GT and unique FF transitions for astrophysical applications. $^{86,88...

  16. Beta-decay in odd-A and even-even proton-rich Kr isotopes

    CERN Document Server

    Sarriguren, P; Escuderos, A

    2001-01-01

    Beta-decay properties of proton-rich odd-A and even-even Krypton isotopes are studied in the framework of a deformed selfconsistent Hartree-Fock calculation with density-dependent Skyrme forces, including pairing correlations between like nucleons in BCS approximation. Residual spin-isospin interactions are consistently included in the particle-hole and particle-particle channels and treated in Quasiparticle Random Phase Approximation. The similarities and differences in the treatment of even-even and odd-A nuclei are stressed. Comparison to available experimental information is done for Gamow-Teller strength distributions, summed strengths, and half-lives. The dependence of these observables on deformation is particularly emphasized in a search for signatures of the shape of the parent nucleus.

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

    International Nuclear Information System (INIS)

    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

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

    Indian Academy of Sciences (India)

    H Ejiri

    2001-08-01

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

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

    OpenAIRE

    Zuber, K.

    2000-01-01

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

  20. A background free double beta decay experiment

    CERN Document Server

    Giomataris, Ioannis

    2010-01-01

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

  1. Search for double beta decay of 106Cd in TGV-2 experiment

    International Nuclear Information System (INIS)

    Search for double beta decay (β+β+, β+/EC, EC/EC) of 106Cd was performed at the Modane underground laboratory (4800 m w.e.) using a spectrometer TGV-2 with 32 HPGe detectors. New limits on the half-lives of 0vEC/EC resonant decay - T1/2 ≥ 1.6 x 1020 y, and on 2vEC/EC decay of 106Cd - T1/2 ≥ 4.1 x 1020 y (at 90% CL) were obtained from preliminary calculations of experimental data accumulated for 12900 h of measurement of ∼13.6 g of 106Cd with enrichment of 75%. The limits on 2vEC/EC decay of 106Cd to the 2+,512 keV and 0+1,1334 keV excited states of 106Pd and on 2vβ+β+ and 2vβ+/EC decay of 106Cd were improved

  2. Search for double beta decay of 106Cd in TGV-2 experiment

    Science.gov (United States)

    Rukhadze, N. I.; Briançon, Ch; Brudanin, V. B.; Čermák, P.; Egorov, V. G.; Klimenko, A. A.; Kovalik, A.; Shitov, Yu A.; Štekl, I.; Timkin, V. V.; Vylov, Ts

    2010-01-01

    Search for double beta decay (β+β+, β+/EC, EC/EC) of 106Cd was performed at the Modane underground laboratory (4800 m w.e.) using a spectrometer TGV-2 with 32 HPGe detectors. New limits on the half-lives of 0vEC/EC resonant decay - T1/2 >= 1.6 × 1020 y, and on 2vEC/EC decay of 106Cd - T1/2 >= 4.1 × 1020 y (at 90% CL) were obtained from preliminary calculations of experimental data accumulated for 12900 h of measurement of ~13.6 g of 106Cd with enrichment of 75%. The limits on 2vEC/EC decay of 106Cd to the 2+,512 keV and 0+1,1334 keV excited states of 106Pd and on 2vβ+β+ and 2vβ+/EC decay of 106Cd were improved

  3. Neutrinoless double beta decay search with SNO+

    OpenAIRE

    Lozza V.

    2014-01-01

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

  4. 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.

  5. Beta decay of the exotic $T_z$ = -2 nuclei $^{48}$Fe, $^{52}$Ni and $^{56}$Zn

    CERN Document Server

    Orrigo, S E A; Fujita, Y; Gelletly, W; Agramunt, J; Algora, A; Ascher, P; Bilgier, B; Blank, B; Cáceres, L; Cakirli, R B; Ganioğlu, E; Gerbaux, M; Giovinazzo, J; Grévy, S; Kamalou, O; Kozer, H C; Kucuk, L; Kurtukian-Nieto, T; Molina, F; Popescu, L; Rogers, A M; Susoy, G; Stodel, C; Suzuki, T; Tamii, A; Thomas, J C

    2016-01-01

    The results of a study of the beta decays of three proton-rich nuclei having $T_z$ = -2, namely $^{48}$Fe, $^{52}$Ni and $^{56}$Zn, produced in an experiment carried out at GANIL, are reported. In all the cases we have extracted the half-lives and the total $\\beta$-delayed proton emission branching ratios. We have measured the individual $\\beta$-delayed protons and $\\beta$-delayed $\\gamma$ rays with their branching ratios. Decay schemes have been determined for the three nuclei, and new energy levels are identified in the corresponding daughter nuclei. Competition between $\\beta$-delayed protons and gammas is observed in the de-excitation of the $T$ = 2 Isobaric Analogue States in all three cases. Absolute Fermi and Gamow-Teller transition strengths have been determined. The mass excesses of the nuclei under study have been deduced. In addition, we discuss in detail the data analysis taking as a test case $^{56}$Zn, where the exotic $\\beta$-delayed $\\gamma$-proton decay has been observed.

  6. Beta decay of deformed r-process nuclei near A = 80 and A= 160, including odd-A and odd-odd nuclei, with the Skyrme finite-amplitude method

    CERN Document Server

    Shafer, T; Fröhlich, C; McLaughlin, G C; Mumpower, M; Surman, R

    2016-01-01

    After identifying the nuclei in the regions near A =80 and A = 160 for which beta-decay rates have the greatest effect on weak and main r-process abundance patterns, we apply the finite-amplitude method (FAM) with Skyrme energy-density functionals (EDFs) to calculate beta-decay half-lives of those nuclei in the quasiparticle random-phase approximation (QRPA). We use the equal filling approximation to extend our implementation of the charge-changing FAM, which incorporates pairing correlations and allows axially symmetric deformation, to odd-A and odd-odd nuclei. Within this framework we find differences of up to a factor of seven between our calculated beta-decay half-lives and those of previous efforts. Repeated calculations with nuclei near A = 160 and multiple EDFs show a spread of two to four in beta-decay half-lives, with differences in calculated Q values playing an important role. We investigate the implications of these results for r-process simulations.

  7. Isospin and quarks in nuclear beta-decay

    International Nuclear Information System (INIS)

    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 WR. (Author) 52 refs., 4 figs., 2 tabs

  8. Neutrinoless double beta decay search with SNO+

    Science.gov (United States)

    Lozza, V.

    2014-01-01

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

  9. Semiconductor detectors and double beta decay

    International Nuclear Information System (INIS)

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

  10. The NEXT double beta decay experiment

    Science.gov (United States)

    Laing, A.; NEXT Collaboration

    2016-05-01

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

  11. 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.

  12. Calculation of α half-lives for Z ≥ 94 nuclei by proximity potential with a new universal function

    International Nuclear Information System (INIS)

    The half-lives of even–even nuclei with proton number Z ≥ 94 are calculated by proximity potential with a new universal function, especially for superheavy nuclei. The calculation results are compared to the experimental data. It is shown that from the presently obtained universal function, the calculated half-lives of α decay can basically keep agreement with the experimental data for most of even–even nuclei. Those of superheavy nuclei are also calculated and discussed. (author)

  13. Beta decay properties from a statistical model

    International Nuclear Information System (INIS)

    The present work assumes that any intrinsic structure in the nuclei involved is not important. Only spin, parity, and energy are considered. Quantities such as half-life, average beta energy, or average gamma energy can be obtained by integrals over the beta strength function weighted by kinematic and other factors. The beta strength function is proportional to the level density multiplied by a reduced transition probability. Delayed neutron emission is calculated by assuming that the daughter is a compound nucleus which then statistically decays as in the Hauser-Feshbach approach. Using the ENDF/B-V fission product file which contains 877 nuclei, energy-dependent reduced transition probabilities were found for allowed 0+ → 1+ transitions (50 cases) and for other allowed transitions (over 600 cases), corresponding to log ft values of 4.3 and 5.6 respectively. No dependence on either transition energy or on mass was found. A reduced transition probability corresponding to log ft of 7.1 was used for first forbidden transitions. Some results are presented and discussed

  14. 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.

  15. 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.

  16. COBRA - Double beta decay searches using CdTe detectors

    OpenAIRE

    Zuber, K.

    2001-01-01

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

  17. Study of 193Os beta- decay

    International Nuclear Information System (INIS)

    In this work, the excited levels of 193Ir populated by the beta- decay of 193Os (T1/2 ∼ 30h) were investigated. For that purpose, ∼ 5 mg samples of 99%-enriched 192Os were irradiated under a thermal neutron flux of ∼ 1012 s-1 and then analysed both using single gamma spectroscopy and a 4-detector multi parametric acquisition facility, which provided data for both a gamma gamma coincidence analysis and a directional angular correlation gamma gamma (θ ) study. From these data, 28 transitions were added to this decay scheme, 11 of which were previously known from nuclear reactions and 17 observed for the first time. Eight excited levels were also added to the decay scheme, 3 of which were known from nuclear reaction studies - the remaining 5 are suggested for the first time. Moreover, it was possible to confirm suspicions found in reference that the levels at 848.93 keV and 849.093 keV are indeed the same; it was also possible to confirm the existence of an excited level at 806.9 keV, which had been inferred, but not experimentally confirmed in beta decay studies to date. The angular correlation analysis allowed for the definition of the spin of the excited level at 874 keV as 5/2+; moreover, the results showed a 79% probability that the spin of the 1078 keV level is 5/2/'-, and also restricted the spin possibilities for the new excited level at 960 keV to two values (1/2 or 3/2). It was also possible to measure the multipolarity mixing ratio (δLn+1/Ln) for 43 transitions - 19 of them for the first time and most of the others with a better precision than previously known. Finally, an attempt was made to understand the low-lying levels structure for this nucleus using a theoretical model, which reproduced the ground state and the two lowest-lying excited levels in 193Ir. (author)

  18. Neutrinoless Double Beta Decay: 2015 Review

    Directory of Open Access Journals (Sweden)

    Stefano Dell’Oro

    2016-01-01

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

  19. A massive neutrino in nuclear beta decay?

    International Nuclear Information System (INIS)

    We have continued our studies of the p-spectrum of 14C using a germanium detector doped with 14C. There is a feature in the β-spectrum 17 keV below the endpoint which could be explained by the hypothesis that there is a heavy neutrino emitted in the β-decay of 14C with a mass of 17±1 keV and an emission probability of 1.26±0.25%. However, we also have performed a high statistics measurement of the inner bremsstrahlung spectrum of 55Fe and find no indication of the emission of a 17-keV neutrino. We conclude that the origin of the ''kink'' that has been observed in some recent beta spectral measurements is not a neutrino

  20. Neutrinoless Double Beta Decay with SNO+

    CERN Document Server

    Hartnell, J

    2012-01-01

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

  1. A massive neutrino in nuclear beta decay?

    International Nuclear Information System (INIS)

    We have continued our studies of the β-spectrum of 14C using a germanium detector doped with l4C. There is a feature in the β-spectrum 17 keV below the endpoint which could be explained by the hypothesis that there is a heavy neutrino emitted in the β-decay of 14C with a mass of 17±1 keV and an emission probability of 1.26±0.25%. However, we also have performed a high statistics measurement of the inner bremsstrahlung spectrum of 55Fe and find no indication of the emission of a 17-keV neutrino. We conclude that the origin of the ''kink'' that has been observed in some recent beta spectral measurements is not a neutrino

  2. A massive neutrino in nuclear beta decay?

    International Nuclear Information System (INIS)

    We have continued our studies of the β-spectrum of 14C using a germanium detector doped with 14C. There is a feature in the β-spectrum 17 keV below the endpoint which could be explained by the hypothesis that there is a heavy neutrino emitted in the β-decay of 14C with a mass of 17±1 keV and an emission probability of 1.26±0.25%. However, we also have performed a high statistics measurement of the inner bremsstrahlung spectrum of 55Fe and find no indication of the emission of a 17-keV neutrino. We conclude that the origin of the ''kink'' that has been observed in some recent beta spectral measurements is not a neutrino

  3. Influence of 2p-2h configurations on beta-decay rates

    CERN Document Server

    Severyukhin, A P; Borzov, I N; Arsenyev, N N; Van Giai, Nguyen

    2014-01-01

    The effects of the phonon-phonon coupling on the beta-decay rates of neutron-rich nuclei are studied in a microscopic model based on Skyrme-type interactions. The approach uses a finite-rank separable approximation of the Skyrme-type particle-hole (p-h) residual interaction. Very large two-quasiparticle spaces can thus be treated. A redistribution of the Gamow-Teller (G-T) strength is found due to the tensor correlations and the 2p-2h fragmentation of G-T states. As a result, the beta-decay half-lives are decreased significantly. Using the Skyrme interaction SGII together with a volume-type pairing interaction we illustrate this reduction effect by comparing with available experimental data for the Ni isotopes and neutron-rich N=50 isotones. We give predictions for 76Fe and 80Ni in comparison with the case of the doubly-magic nucleus 78Ni which is an important waiting point in the r-process.

  4. Measurement of beta decay periods for Fe-Ni neutrons rich isotopes

    International Nuclear Information System (INIS)

    Thermal fission of 239 Pu was used to produce 68,69 Co and 68 Fe isotopes, the lightest ones ever observed in thermal fission, at the ILL high-flux reactor, in Grenoble. Separated with the Lohengrin recoil spectrometer, then identified by means of a Δ E-E ionization chamber, fragments were implanted in a set of Si-detectors, where β-particles were detected too. The fission yields were determined, and the beta-decay half-lives were extracted from delayed coincidence analysis between ion implantation and the subsequent beta detection: They were found to be 0.27±0.05s, 0.18±0.10s, and 0.10±0.06s respectively for 69 Co, 68 Co, and 68 Fe. This method was adapted to a new experimental configuration: 65 Fe isotopes were produced from 86 Kr projectile fragmentation at 500 MeV/u on a Be target. Selected ions were separated with the fragment separator FRS at GSI (Darmstadt), tuned in the monoenergetic mode. Fragments were identified by ΔE-ToF, slowed down, and then implanted in two rows of PIN-diodes that provided an additional range selection. The half-life were determined from the analysis of the decay chain Fe-Co-Ni: it was found 0.4±0.2s. Production rates obtained with the two methods are compared at the end of this work

  5. First-forbidden $\\mathbf{\\beta}$-decay rates, energy rates of $\\beta$-delayed neutrons and probability of $\\beta$-delayed neutron emissions for neutron-rich nickel isotopes

    CERN Document Server

    Nabi, Jameel-Un; Iftikhar, Zafar

    2016-01-01

    First-forbidden (FF) transitions can play an important role in decreasing the calculated half-lives specially in environments where allowed Gamow-Teller (GT) transitions are unfavored. Of special mention is the case of neutron-rich nuclei where, due to phase-space amplification, FF transitions are much favored. We calculate the allowed GT transitions in various pn-QRPA models for even-even neutron-rich isotopes of nickel. Here we also study the effect of deformation on the calculated GT strengths. The FF transitions for even-even neutron-rich isotopes of nickel are calculated assuming the nuclei to be spherical. Later we take into account deformation of nuclei and calculate GT + unique FF transitions, stellar $\\beta$-decay rates, energy rate of $\\beta$-delayed neutrons and probability of $\\beta$-delayed neutron emissions. The calculated half-lives are in excellent agreement with measured ones and might contribute in speeding-up of the $r$-matter flow.

  6. Neutron bound beta-decay: BOB

    International Nuclear Information System (INIS)

    An experiment to observe the bound beta-decay (BOB) of the free neutron into a hydrogen atom and an electron anti-neutrino is described. The hyperfine spin state population of the monoenergetic hydrogen atom yields the neutrino left-handedness or possible right-handed admixture as well as possible small scalar and tensor contributions to the weak force. The BOB H(2s) hyperfine states can be separated with a Lamb-Shift Spin Filter. These monoenergetic H(2s) atoms are ionised into H− by charge exchanging within an argon cell. These ions are then separated using an adaptation of a MAC-E Filter. A first experiment is proposed at the FRMII high thermal-neutron flux beam reactor SR6 through-going beam tube, where we will seek to observe this rare neutron decay-mode for the first time and determine the branching ratio. After successful completion, the hyperfine spin state population will be determined, possibly at the ILL high-flux beam reactor through-going beam tube H6–H7, where the thermal neutron flux is a factor of four larger.

  7. Double beta decay of 128Te and RIS

    International Nuclear Information System (INIS)

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

  8. Scalar-mediated double beta decay and LHC

    CERN Document Server

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

    2016-01-01

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

  9. Tests of Lorentz Symmetry in Single Beta Decay

    International Nuclear Information System (INIS)

    Low-energy experiments studying single beta decay can serve as sensitive probes of Lorentz invariance that can complement interferometric searches for deviations from this spacetime symmetry. Experimental signatures of a dimension-three operator for Lorentz violation which are unobservable in neutrino oscillations are described for the decay of polarized and unpolarized neutrons as well as for measurements of the spectral endpoint in beta decay

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

    International Nuclear Information System (INIS)

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

  11. NEMO 3 double beta decay experiment: latest results

    CERN Document Server

    Barabash, A S

    2008-01-01

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

  12. Beta decay rates of nuclei with 65 < < 75 for pre-supernova and supernova evolution

    Indian Academy of Sciences (India)

    Debasish Majumdar; Kamales Kar

    2007-03-01

    The half-lives are calculated for the - decay process for nuclei in the mass range ∼ 65-75 relevant for the core of a massive star at the late burning stage of stellar evolution and the collapse that leads to supernova explosion. These half-lives and rates are calculated by expressing the - Gamow-Teller decay strengths in terms of smoothed bivariate strength densities. These strength densities are constructed in the framework of spectral averaging theory for two-body nuclear Hamiltonian in a large nuclear shell model space. The method has a natural extension to electron captures as well as weak interaction rates for and -processes.

  13. Half-Lives of 101Rh and 108m Ag

    Science.gov (United States)

    Norman, Eric; Browne, Edgardo; Shugart, Howard

    2014-09-01

    Half-lives of short-lived nuclei can easily be measured by direct counting techniques, whereas those of long-lived naturally-occurring nuclei are usually determined by specific activity measurements. However, half-lives in the range of 1 - 1,000,000 years are notoriously difficult to determine. For example, published values for the half-life of 101Rh range from 3.0 +/- 0.4 years to 10 +/- 1 years, and for 108m Ag published values range from 127 +/- 21 years to 438 +/- 9 years. In order to resolve the issues of what the half-lives of these isotopes actually are, we set up two separate long-term gamma-ray counting experiments. Gamma-ray data were collected in time bins using high-purity Ge detectors and ORTEC PC-based data acquisition systems. We counted in this manner for a period of approximately 5 years for 101Rh and 3 years for 108mAg. In this talk we will describe the details of these experiments and will present the final results for the half-lives of 101Rh and 108mAg determined from these measurements. Half-lives of short-lived nuclei can easily be measured by direct counting techniques, whereas those of long-lived naturally-occurring nuclei are usually determined by specific activity measurements. However, half-lives in the range of 1 - 1,000,000 years are notoriously difficult to determine. For example, published values for the half-life of 101Rh range from 3.0 +/- 0.4 years to 10 +/- 1 years, and for 108m Ag published values range from 127 +/- 21 years to 438 +/- 9 years. In order to resolve the issues of what the half-lives of these isotopes actually are, we set up two separate long-term gamma-ray counting experiments. Gamma-ray data were collected in time bins using high-purity Ge detectors and ORTEC PC-based data acquisition systems. We counted in this manner for a period of approximately 5 years for 101Rh and 3 years for 108mAg. In this talk we will describe the details of these experiments and will present the final results for the half-lives of 101Rh

  14. Estimating Half-Lives for Pesticide Dissipation from Plants

    DEFF Research Database (Denmark)

    Fantke, Peter; Gillespie, Brenda W.; Juraske, Ronnie;

    2014-01-01

    Pesticide risk and impact assessment models critically rely on and are sensitive to information describing dissipation from plants. Despite recent progress, experimental data are not available for all relevant pesticide−plant combinations, and currently no model predicting plant dissipation...... dissipation data to estimate half-lives based on substance properties at the level of chemical substance class. Estimated half-lives from our study are designed to be applied in risk and impact assessment models to either directly describe dissipation or as first proxy for describing degradation....

  15. Tests of the standard electroweak model in beta decay

    International Nuclear Information System (INIS)

    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 CA,/CV = -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)

  16. 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)

  17. New particle searches by double beta decay

    International Nuclear Information System (INIS)

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

  18. T violation in radiative $\\beta$ decay and electric dipole moments

    CERN Document Server

    Dekens, W G

    2015-01-01

    In radiative $\\beta$ decay, $T$ violation can be studied through a spin-independent $T$-odd correlation. We consider contributions to this correlation by beyond the standard model (BSM) sources of $T$-violation, arising above the electroweak scale. At the same time such sources, parametrized by dimension-6 operators, can induce electric dipole moments (EDMs). As a consequence, the manifestations of the $T$-odd BSM physics in radiative $\\beta$ decay and EDMs are not independent. Here we exploit this connection to show that current EDM bounds already strongly constrain the spin-independent $T$-odd correlation in radiative $\\beta$ decay.

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

    CERN Document Server

    Zhang, Jue

    2016-01-01

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

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

    OpenAIRE

    Osland, Per; Vigdel, Geir

    2001-01-01

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

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

    CERN Document Server

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

    2009-01-01

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

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

    CERN Document Server

    Barabash, A S

    2012-01-01

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

  3. Complementarity of Neutrinoless Double Beta Decay and Cosmology

    Energy Technology Data Exchange (ETDEWEB)

    Dodelson, Scott; Lykken, Joseph

    2014-03-20

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

  4. Status and Perspectives of Double Beta Decay Searches

    Science.gov (United States)

    Zuber, K.

    2015-11-01

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

  5. New exotics in the double beta decay contributions zoo

    OpenAIRE

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

    2000-01-01

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

  6. 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.

  7. Status of the COBRA double beta decay experiment

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-01-01

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

  8. Status of the COBRA double beta decay experiment

    International Nuclear Information System (INIS)

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

  9. Search for neutrinoless double beta decay with DCBA

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-05-15

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

  11. New Half-life Limits on Double Beta Decays of Pd110 and Pd102 into Excited States

    CERN Document Server

    Lehnert, Bjoern; Andreotti, Erica; Hult, Mikael

    2012-01-01

    A search for excited state transitions of double beta decay in Pd110 and double electron capture in Pd102 has been performed in the HADES underground laboratory with two low background HPGe detectors in sandwich configuration. After an exposure of 35.92 kg*d, no signal was found. The frequentist spectral analysis resulted in lower half-life limits of 1.98e20 yr and 1.72e20 yr (95% CL) for the first 0+ and 2+ excited state in Pd110 respectively. This is an improvement by more than a factor of 3 with respect to previous measurements. In Pd102, the lower half-life limit could be improved to 5.95e18 yr (95% CL) for the first 0+ excited state. Furthermore, first experimental lower half-live limits are found for all possible excited states in the Pd110 and Pd102 systems.

  12. Microscopic quasiparticle-phonon description of beta decays of {sup 113}Cd and {sup 115}In using proton-neutron phonons

    Energy Technology Data Exchange (ETDEWEB)

    Mustonen, M.T. [Department of Physics, University of Jyvaeskylae, PO Box 35, FIN-40351 Jyvaeskylae (Finland)], E-mail: mika.t.mustonen@jyu.fi; Suhonen, J. [Department of Physics, University of Jyvaeskylae, PO Box 35, FIN-40351 Jyvaeskylae (Finland)], E-mail: jouni.suhonen@phys.jyu.fi

    2007-11-29

    The fourth-forbidden non-unique ground-state-to-ground-state beta decays of {sup 113}Cd and {sup 115}In are calculated using a realistic microscopic two-body interaction and a realistic single-particle model space. To describe the involved initial and final nuclear states we introduce a proton-neutron variant of the microscopic quasiparticle-phonon model (MQPM), the proton-neutron MQPM (pnMQPM). The states of the pnMQPM are created by coupling quasiparticles with phonons of the proton-neutron quasiparticle random-phase approximation (pnQRPA). The computed half-lives and logft values are found to be in excellent agreement with experimental data. Computed beta spectra of the decays are also given.

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

    International Nuclear Information System (INIS)

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

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

    CERN Document Server

    Schwingenheuer, Bernhard

    2012-01-01

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

  15. Beta-decay of nuclei around Se-90. Search for signatures of a N=56 sub-shell closure relevant the r-process

    CERN Document Server

    Quinn, M; Pereira, J; Surman, R; Arndt, O; Baumann, T; Becerril, A; Elliot, T; Estrade, A; Galaviz, D; Ginter, T; Hausmann, M; Hennrich, S; Kessler, R; Kratz, K -L; Lorusso, G; Mantica, P F; Matos, M; Moller, P; Montes, F; Pfeiffer, B; Portillo, M; Hennrich, S; Schatz, H; Schertz, F; Schnorrenberger, L; Smith, E; Stolz, A; Walters, W B; Wohr, A

    2011-01-01

    Nuclear structure plays a significant role on the rapid neutron capture process (r-process) since shapes evolve with the emergence of shells and sub-shells. There was some indication in neighboring nuclei that we might find examples of a new N=56 sub-shell, which may give rise to a doubly magic Se-90 nucleus. Beta-decay half lives of nuclei around Se-90 have been measured to determine if this nucleus has in fact a doubly-magic character. The fragmentation of Xe-136 beam at the National Superconducting Cyclotron Laboratory at Michigan State University was used to create a cocktail of nuclei in the A=90 region. We have measured the half lives of twenty-two nuclei near the r-process path in the A=90 region. The half lives of As-88 and Se-90 have been measured for the first time. The values were compared with theoretical predictions in the search for nuclear-deformation signatures of a N=56 sub-shell, and its possible role in the emergence of a potential doubly-magic Se-90. The impact of such hypothesis on the sy...

  16. Unique forbidden beta decays and neutrino mass

    Energy Technology Data Exchange (ETDEWEB)

    Dvornický, Rastislav, E-mail: dvornicky@dnp.fmph.uniba.sk [Dzhelepov Laboratory of Nuclear Problems, JINR 141980 Dubna (Russian Federation); Comenius University, Mlynská dolina F1, SK-842 48 Bratislava (Slovakia); Šimkovic, Fedor [Comenius University, Mlynská dolina F1, SK-842 48 Bratislava (Slovakia); Boboliubov Laboratory of Theoretical Physics, JINR 141980 Dubna (Russian Federation); Czech Technical University in Prague, 128-00 Prague (Czech Republic)

    2015-10-28

    The measurement of the electron energy spectrum in single β decays close to the endpoint provides a direct determination of the neutrino masses. The most sensitive experiments use β decays with low Q value, e.g. KATRIN (tritium) and MARE (rhenium). We present the theoretical spectral shape of electrons emitted in the first, second, and fourth unique forbidden β decays. Our findings show that the Kurie functions for these unique forbidden β transitions are linear in the limit of massless neutrinos like the Kurie function of the allowed β decay of tritium.

  17. Status and perspectives of double beta decay searches

    International Nuclear Information System (INIS)

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

  18. Neutrinoless Double Beta Decay and High-Scale Baryogenesis

    CERN Document Server

    Graf, Lukas; Huang, Wei-Chih

    2015-01-01

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

  19. Beta-decay properties of $^{25}$Si and $^{26}$P

    CERN Document Server

    Thomas, J C; Äystö, J; Béraud, R; Blank, B; Canchel, G; Czajkowski, S; Dendooven, P; Ensallem, A; Giovinazzo, J; Guillet, N; Honkanen, J; Jokinen, A; Laird, A M; Lewitowicz, M; Longour, C; De Santos, F O; Peräjärvi, K; democrite-00023307, ccsd

    2004-01-01

    The $\\beta$-decay properties of the neutron-deficient nuclei $^{25}$Si and $^{26}$P have been investigated at the GANIL/LISE3 facility by means of charged-particle and $\\gamma$-ray spectroscopy. The decay schemes obtained and the Gamow-Teller strength distributions are compared to shell-model calculations based on the USD interaction. B(GT) values derived from the absolute measurement of the $\\beta$-decay branching ratios give rise to a quenching factor of the Gamow-Teller strength of 0.6. A precise half-life of 43.7 (6) ms was determined for $^{26}$P, the $\\beta$- (2)p decay mode of which is described.

  20. Status and perspectives of double beta decay searches

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-07-01

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

  1. 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...... 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....

  2. Deformed shell model results for neutrinoless double beta decay of nuclei in A = 60 - 90 region

    International Nuclear Information System (INIS)

    Nuclear transition matrix elements (NTME) for the neutrinoless double beta decay (Oνββ or OνDBD) of 70Zn, 80Se and 82Se nuclei are calculated within the framework of the deformed shell model (DSM) based on Hartree–Fock (HF) states. For 70Zn, jj44b interaction in 2p3/2, 1f5/2, 2p1/2 and 1g9/2 space with 56Ni as the core is employed. However, for 80Se and 82Se nuclei, a modified Kuo interaction with the above core and model space are employed. Most of our calculations in this region were performed with this effective interaction. However, jj44b interaction has been found to be better for 70Zn. The above model space was used in many recent shell model (SM) and interacting boson model (IBM) calculations for nuclei in this region. After ensuring that DSM gives good description of the spectroscopic properties of low-lying levels in these three nuclei considered, the NTME are calculated. The deduced half-lives with these NTME, assuming neutrino mass is 1 eV, are 1.1 × 1026, 2.3 × 1027 and 2.2 × 1024 yr for 70Zn, 80Se and 82Se, respectively. (author)

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

    International Nuclear Information System (INIS)

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

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

    CERN Document Server

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

    2016-01-01

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

  5. Short-range correlations and neutrinoless double beta decay

    CERN Document Server

    Kortelainen, M; Suhonen, J; Toivanen, J

    2007-01-01

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

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

    CERN Document Server

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

    2007-01-01

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

  7. A search for double beta decay of 136Xe

    International Nuclear Information System (INIS)

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

  8. Sensitivity of CUORE to Neutrinoless Double-Beta Decay

    CERN Document Server

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

    2011-01-01

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

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

    OpenAIRE

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

    2005-01-01

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

  10. Search for beta sup - and beta sup -beta sup - decays of sup 4 sup 8 Ca

    CERN Document Server

    Bakalyarov, A; Barabash, A; Briançon, C; Brudanin, V; Egorov, V; Hubert, F; Hubert, P; Kovalik, A; Lebedev, V I; Rukhadze, N I; Stekl, I; Umatov, V; Vylov, T D

    2002-01-01

    A sup 4 sup 8 CaCO sub 3 powder sample containing 20.18 g of sup 4 sup 8 Ca was measured for 797 h with a 400 cm sup 3 low-background HPGe detector. New limits on decays of sup 4 sup 8 Ca were obtained. For single beta transitions to sup 4 sup 8 Sc the limits are equal to 0.71x10 sup 2 sup 0 y, 1.1x10 sup 2 sup 0 y, and 0.82x10 sup 2 sup 0 y for transitions to the ground state, excited 5 sup + and 4 sup + states, respectively. The new limits on double beta decay to excited states of sup 4 sup 8 Ti are equal to 0.47x10 sup 2 sup 0 y, 1.1x10 sup 2 sup 0 y, and 0.90x10 sup 2 sup 0 y for transitions to the first 2 sup + , second 2 sup + and first 0 sup + excited states, respectively. All limits are given at the 90% CL.

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

    CERN Document Server

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

    2010-01-01

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

  12. 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.

  13. Possible background reductions in double beta decay experiments

    CERN Document Server

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

    2003-01-01

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

  14. Momentum analyzers DCBA for neutrinoless double beta decay experiments

    International Nuclear Information System (INIS)

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

  15. Momentum analyzers DCBA for neutrinoless double beta decay experiments

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-11-01

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

  16. Neutron beta decay and the right-handed current problem

    Energy Technology Data Exchange (ETDEWEB)

    Gaponov, Yu.V.; Shul' gina, N.B.; Spivak, P.E. (Gosudarstvennyj Komitet po Ispol' zovaniyu Atomnoj Ehnergii SSSR, Moscow (USSR). Inst. Atomnoj Ehnergii)

    1991-01-10

    The renormalization of the axial-vector coupling constant, {lambda}=g{sub A}/g{sub V}, extracted from the neutron lifeime ({lambda}{sub tau}) and from the neutron beta decay asymmetry ({lambda}{sub c}) is considered carefully in the standard model of the electroweak interaction {lambda}{sub tau} should be equal to {lambda}{sub c}. According to recent experimental data on neutron beta decay, {lambda}{sub tau} and {lambda}{sub c} seem to differ from each other. This fact is explained in the framework of the manifestly left-right symmetric model SU(2){sub L}xSU(2){sub R}xU(1). The possibility of the existence of the right-handed current in the neutron beta decay is pointed out. A joint analysis of neutron beta decay and muon decay is performed, the right-handed current parameters are estimated. The axial-vector constant renormalization ({lambda}{sub N}) by right-handed currents is evaluated. (orig.)D.

  17. Perturbative description of nuclear double beta decay transitions

    OpenAIRE

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

    1998-01-01

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

  18. Nuclear Structure Aspects of Neutrinoless Double Beta Decay

    CERN Document Server

    Brown, B A; Sen'kov, R A

    2014-01-01

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

  19. 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.

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

    International Nuclear Information System (INIS)

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

  1. Beta-decay of 20Mg

    International Nuclear Information System (INIS)

    The β-decay of 20Mg was investigated. A secondary beam of 20Mg ions, produced in reactions between a 95 A x MeV 24Mg-beam and a nat.Ni-target, was isotopically separated by means of the LISE3 spectrometer at GANIL. This secondary beam was implanted into a silicon detector array surrounded by germanium γ-detectors. The β-delayed proton and γ-ray data, measured for this short-lived nucleus (T1/2=95±3 ms), were incorporated into an improved 20Mg→20Na decay scheme. The 2645 keV level in 20Na is of importance for the breakout from the astrophysical hot CNO-cycle and the onset of the rapid proton capture process via the reaction 19Ne(p,γ)20Na. An upper limit of 0.1% for the β-decay feeding of the 2645 keV level and a lower limit for the corresponding log ft value of 6.24 were determined. The implications of this result for the spin and parity assignment of the 2645 keV state are discussed. Concerning the isobaric multiplet mass equation no significant deviation from its quadratic form was found. By comparing the 20Mg β-decay into the proton-unbound 3001 keV state in 20Na and the isospin-mirrored decay into the particle-bound 3488 keV level in 20F, an asymmetry ft+/ft--1=1.69-0.65+0.86 was observed. (orig.)

  2. Measuring pion beta decay with high-energy pion beams

    International Nuclear Information System (INIS)

    Improved measurements of the pion beta decay rate are possible with an intense high-energy pion beam. The rate for the decay π+ → π0e+vε is predicted by the Standard Model (SM) to be R(π+ → π0e+vε) = 0.3999±0.0005 s-1. The best experimental number, obtained using in-flight decays, is R(π+ → π0e+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

  3. Ordinary muon capture as a probe of virtual transitions of $\\beta\\beta$ decay

    CERN Document Server

    Kortelainen, M

    2002-01-01

    A reliable theoretical description of double-beta-decay processes needs a possibility to test the involved virtual transitions against experimental data. Unfortunately, only the lowest virtual transition can be probed by the traditional electron-capture or $\\beta^-$-decay experiments. In this article we propose that calculated amplitudes for many virtual transitions can be probed by experiments measuring rates of ordinary muon capture (OMC) to the relevant intermediate states. The first results from such experiments are expected to appear soon. As an example we discuss the $\\beta\\beta$ decays of $^{76}$Ge and $^{106}$Cd and the corresponding OMC for the $^{76}$Se and $^{106}$Cd nuclei in the framework of the proton-neutron QRPA with realistic interactions. It is found that the OMC observables, just like the $2\

  4. The beta strength function structure in \\beta + decay of lutecium, thulium and cesium isotopes

    CERN Document Server

    Alkhazov, G D; Naumov, Yu V; Orlov, S Yu; Vitman, V D

    1981-01-01

    The spectra of total gamma -absorption in the decays of some lutetium, thulium and cesium isotopes have been measured. The probabilities for level population in the decay of the isotopes have been determined. The deduced beta strength functions reveal pronounced structure. Calculations of the strength functions using the Saxon-Woods potential and the residual Gamow-Teller interaction are presented. It is shown that in beta /sup +/ decay of light thulium and cesium isotopes the strength function comprises more than 70% of the Gamow-Teller excitations with mu /sub tau /=+1. This result is the first direct observation of the Gamov-Teller resonance in beta /sup +/ decay of nuclei with T/sub z/>0. (21 refs).

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

    CERN Document Server

    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.

  6. Computer code for double beta decay QRPA based calculations

    International Nuclear Information System (INIS)

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

  7. Evaluation of beta-decay III. The complex gamma function

    International Nuclear Information System (INIS)

    Two real, analytical, approximations for the square of the modulus of the complex gamma function as it appears in F(Z, W), the Fermi function for beta-decay, are evaluated; an accuracy bettering 10-4% can easily be achieved for all electron energies throughout the periodic table. (author). 3 refs., 1 tab., 7 figs

  8. A cryogenic microcalorimeter for tritium beta decay experiments

    International Nuclear Information System (INIS)

    Recent tritium beta decay spectrometer experiments have produced puzzling results, making it desirable to perform a similar experiment with a completely different type of detector. Cryogenic microcalorimeters offer a possible detector technology for this type of experiment. Presented here is a design for, and results of experiments with, a cryogenic microcalorimeter designed for use in tritium beta decay experiments. The biggest challenge in designing a microcalorimeter for beta decay experiments is the speed at which the detector operates. A fast detector is essential to obtain the necessary statistics near the beta spectrum endpoint. .The detector was designed with a normal metal absorber and a bilayer super-conducting transition-edge sensor. These design elements are meant to minimize the pulse rise time and decay time, respectively. Two different detector designs were built and tested in order to determine their operating parameters. These operating parameters were compared to a model describing the operation of these devices and were shown to be in reasonable agreement with it. The model predicts that the detector properties can be improved to the point where a tritium neutrino mass experiment can be performed. Suggestions are given for design modifications that will allow this level of performance. (author)

  9. Forbidden unique beta-decays and neutrino mass

    Energy Technology Data Exchange (ETDEWEB)

    Dvornický, Rastislav [Bogoliubov Laboratory of Theoretical Physics, JINR Dubna, 141980 Dubna, Moscow region, Russian Federation and Department of Nuclear Physics and Biophysics, Comenius University, Mlynská dolina F1, SK-84215 Bratislava (Slovakia); Šimkovic, Fedor [Department of Nuclear Physics and Biophysics, Comenius University, Mlynská dolina F1, SK-84215 Bratislava, Slovakia and IEAP, Czech Technical University, CZ-128 00 Prague (Czech Republic)

    2013-12-30

    The measurement of the electron spectrum in beta-decays provides a robust direct determination of the values of neutrino masses. The planned rhenium beta-decay experiment, called the “Microcalorimeter Arrays for a Rhenium Experiment” (MARE), might probe the absolute mass scale of neutrinos with the same sensitivity as the Karlsruhe tritium neutrino mass (KATRIN) experiment, which is expected to collect data in a near future. In this contribution we discuss the spectrum of emitted electrons close to the end point in the case of the first unique forbidden beta-decay of {sup 79}Se, {sup 107}Pd and {sup 187}Re. It is found that the p{sub 3/2}-wave emission dominates over the s{sub 1/2}-wave. It is shown that the Kurie plot near the end point is within a good accuracy linear in the limit of massless neutrinos like the Kurie plot of the superallowed beta-decay of {sup 3}H.

  10. MeV neutrinos in double beta decay

    OpenAIRE

    Zuber, K.

    1996-01-01

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

  11. Mass Measurement of Very Short Half-Lived Nuclei

    CERN Multimedia

    Duma, M; Iacob, V E; Thibault, C

    2002-01-01

    The MISTRAL (Mass measurements at ISolde with a Transmission RAdiofrequency spectrometer on-Line) experiment exploits a rapid measurement technique to make accurate mass determinations of very short-lived nuclei. The physics goals are to elucidate new nuclear structure effects and constrain nuclear mass models in regions of interest to nuclear astrophysics.\\\\ \\\\The spectrometer, installed in May 97, performed as promised in the proposal with mass resolution exceeding 100,000. In its first experiment in July 1998, neutron-rich Na isotopes having half-lives as short as 31 ms were measured. A second experiment in November 1998 enabled us to improve the measurement precision of the isotopes $^{26-30}$Na to about 20 keV. The measurement program continues as experiment IS 373.

  12. Inner shell ionization in beta decay

    International Nuclear Information System (INIS)

    The purpose of this paper is to examine various ways to resolve the discrepancy that exists between the theoretical calculations on K-shell autoionization probabilities in #betta# decay and the measured values. The chequered history of the subject may be traced through the reviews and papers of Freedman and co workers. Suffice it to say that Isozumi et al (ISM) found that the Law and Campbell (LC) model over counted the shake-off contribution by a factor of two; this correction thus destroys the remarkable agreement between theory and experiment

  13. Searches for massive neutrinos in nuclear beta decay

    International Nuclear Information System (INIS)

    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 mbarνe < 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

  14. 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).

  15. 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.

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

    International Nuclear Information System (INIS)

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

  17. (Beta)-decay experiments and the unitarity of the CKM matrix

    Energy Technology Data Exchange (ETDEWEB)

    Garrett, P E

    2005-12-01

    The goal of this project was to perform very precise measurements of super-allowed Fermi {beta} decay in order to investigate a possible non-unitarity in the CKM matrix of the Standard Model of particle physics. Current data from 9 precisely measured {beta} decays indicated that the sum-of-squares of the first row of the CKM matrix differs from 1.0 at the 2.2{sigma} (or 98% confidence) level. If true, it would be the first firm indication of physics beyond the Standard Model--the model that has been the backbone of the worldwide physics community for more than 30 years. The physics goal of the project was to test and constrain the calculated correction factors that must be applied to the experimental data by performing measurements at the TRIUMF radioactive ion beam facility ISAC. Accurate and precise (precision goal >99.9%) half lives and decay branching ratios were measured for nuclei where different sets of calculated corrections give divergent results thereby allowing us to determine which theory, if any, gives the correct result. The LLNL contribution was to design and build the data acquisition system that will enable the experiments, and to provide theoretical calculations necessary for the interpretation of the results. The first planned measurement was {sup 34}Ar, to be followed by {sup 62}Ga and {sup 74}Rb. However, there were major problems in creating a suitable, intense beam of radioactive {sup 34}Ar. The collaboration decided to proceed with measurements on {sup 62}Ga and {sup 18}Ne. These experiments were performed in a series of measurements in the summer and fall of 2004. The LLNL team also is leading the effort to perform measurements on {sup 66}As and {sup 70}Br that are expected during 2006-2008. While the definitive experiments to meet the goals of the LDRD were not conducted during the funding period, the involvement in the radioactive program at TRIUMF has lead to a number of new initiatives, and has attracted new staff to LLNL. This LDRD has

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-02-01

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

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

    International Nuclear Information System (INIS)

    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 8Li

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

    International Nuclear Information System (INIS)

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

  1. Recording of ecological half-lives of 90Sr and 137Cs in terrestrial and aquatic ecosystems

    International Nuclear Information System (INIS)

    Within this project, the long-term behaviour of 90Sr and 137Cs in foods, feeds and a variety of environmental was analysed. The long-term behaviour is quantified by means of the ecological half-life which integrates all processes that cause a decrease of activity in a given medium as leaching, fixation and erosion. The following results were achieved: - For plant and animal food products, the ecological half-lives are in the range of 4 to 6 and 10 to 20 years for cesium and strontium respectively. The ecological half-lives for the period 1965 to 1985 are slightly shorter than those derived from monitoring measurements performed after 1987, due to the ongoing deposition in the post weapons' fallout period. - According to the German radioecological model that is applied during licensing of nuclear installations to assess radiation exposures to the general due to planned releases, the ecological half-lives for plant food products are 26 and 13 a for cesium and strontium respectively. In radioecological model that is used within the decision support system RODOS, the ecological half-lives are 8 years for Cesium and 14 years for strontium, which agrees well with the finding of this study. - For roe deer, deer, wild boar and forest plants (including mushrooms), under Middle European conditions, the ecological half-lives are about 12 years for cesium. However, in Ukraine, the cesium levels in forest products are much more persistent; in some cases the decrease of activity is only caused by the radioactive decay. - The variability of the long-term behaviour of 137Cs and 90Sr in freshwater ecosystems is much more pronounced than for terrestrial systems. It depends strongly on the sitespecific characteristics. The observed ecological half-lives for 137Cs and 90Sr cover a wide range from several days to several years. - The data to derive ecological half-lives of cesium in soil is relatively poor. For the upper soil layer of 0-10 cm, ecological half-lives were derived ranging

  2. Study of the ${\\beta}$-decay of $^{12}$B

    CERN Multimedia

    2002-01-01

    We propose to study the ${\\beta}$-decay of $^{12}$B with a modern segmented Si-detector array to get new and much improved information on states in $^{12}$C above the ${\\alpha}$-threshold. These states mainly decay into final states of three ${\\alpha}$-particles and their study therefore is a challenge for nuclear spectroscopy. The properties of these states is of high current interest for nuclear astrophysics and for the nuclear many-body problem in general. We ask for a total of 15 shifts.

  3. The GERDA Neutrinoless Double Beta-Decay Experiment

    International Nuclear Information System (INIS)

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

  4. $\\beta$-decay and $\\beta$-delayed Neutron Emission Measurements at GSI-FRS Beyond N=126, for r-process Nucleosynthesis

    CERN Document Server

    Caballero-Folch, R; Cortès, G; Taín, J L; Agramunt, J; Algora, A; Ameil, F; Ayyad, Y; Benlliure, J; Bowry, M; Calviño, F; Cano-Ott, D; Davinson, T; Dillmann, I; Estrade, A; Evdokimov, A; Faestermann, T; Farinon, F; Galaviz, D; García-Ríos, A; Geissel, H; Gelletly, W; Gernhäuser, R; Gómez-Hornillos, M B; Guerrero, C; Heil, M; Hinke, C; Knöbel, R; Kojouharov, I; Kurcewicz, J; Kurz, N; Litvinov, Y; Maier, L; Marganiec, J; Marta, M; Martínez, T; Montes, F; Mukha, I; Napoli, D R; Nociforo, C; Paradela, C; Pietri, S; Podolyák, Zs; Prochazka, A; Rice, S; Riego, A; Rubio, B; Schaffner, H; Scheidenberger, C; Smith, K; Sokol, E; Steiger, K; Sun, B; Takechi, M; Testov, D; Weick, H; Wilson, E; Winfield, J S; Wood, R; Woods, P J; Yeremin, A

    2014-01-01

    New measurements of very exotic nuclei in the neutron-rich region beyond N=126 have been performed at the GSI facility with the fragment separator (FRS). The aim of the experiment is to determine half-lives and beta-delayed neutron emission branching ratios of isotopes of Hg, Tl and Pb in this region. This contribution summarizes final counting statistics for identification and for implantation, as well as the present status of the data analysis of the half-lives. In summary, isotopes of Pt, Au, Hg, Ti, Pb, Bi, Po, At, Rn and Fr were clearly identified and several of them (Hg208-211, Tl211-215, Pb214-218) were implanted with enough statistics to determine their half-lives. About half of them are expected to be neutron emitters, in such cases it will become possible to obtain the neutron emission probabilities, P-n.

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

    CERN Document Server

    Drewes, Marco

    2016-01-01

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

  6. The Majorana Demonstrator search for neutrinoless double beta decay

    CERN Document Server

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

    2016-01-01

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

  7. Collective Effect Studies of a Beta Beam Decay Ring

    CERN Document Server

    Hansen, Christian

    2011-01-01

    The Beta Beam, the concept of generating a pure and intense (anti) neutrino beam by letting accelerated radioactive ions beta decay in a storage ring called the Decay Ring (DR), is the basis of one of the proposed next generation neutrino oscillation facilities, necessary for a complete study of the neutrino oscillation parameter space. Sensitivities of the unknown neutrino oscillation parameters depend on the DR's ion intensity and of its duty factor (the filled ratio of the ring). Different methods, including analytical calculations and multiparticle tracking simulations, were used to estimate the DR's potential to contain enough ions in as small a part of the ring as needed for the sensitivities. Studies of transverse blow up of the beams due to resonance wake fields show that a very challenging upper limit of the transverse broadband impedance is required to avoid instabilities and beam loss.

  8. Collective Effect Studies of a Beta Beam Decay Ring

    International Nuclear Information System (INIS)

    The Beta Beam, the concept of generating a pure and intense (anti) neutrino beam by letting accelerated radioactive ions beta decay in a storage ring called the Decay Ring (DR), is the basis of one of the proposed next generation neutrino oscillation facilities, necessary for a complete study of the neutrino oscillation parameter space. Sensitivities of the unknown neutrino oscillation parameters depend on the DR's ion intensity and of its duty factor (the filled ratio of the ring). Different methods, including analytical calculations and multiparticle tracking simulations, were used to estimate the DR's potential to contain enough ions in as small a part of the ring as needed for the sensitivities. Studies of transverse blow up of the beams due to resonance wake fields show that a very challenging upper limit of the transverse broadband impedance is required to avoid instabilities and beam loss.

  9. A combined limit for neutrinoless double-beta decay

    CERN Document Server

    Guzowski, Pawel

    2015-01-01

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

  10. 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...

  11. BETA DECAY OPENS THE WAY TO WEAK INTERACTIONS

    OpenAIRE

    Amaldi, E.

    1982-01-01

    After a short introduction with some personal recollection, the author summarizes, in Sect 2, the main points of Fermi's theory of beta decay and of the neutrino hypothesis first proposed by Pauli. The successive Sections refer to : a few extensions and modifications of this theory (Sect 3), various experimental investigations carried out in the 30s for testing Pauli's hypothesis and Fermi's approach (Sect 4), further attempts, refinements and proposals (Sect 5) and a few fundamental step for...

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

    International Nuclear Information System (INIS)

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

  13. Beta Decay: A Physics Garden of Earthly Delights

    Science.gov (United States)

    Robertson, R. G. Hamish

    2014-03-01

    From the beginning, beta decay has tormented and delighted us with puzzles and enlightenment. A significant part of our present understanding of subatomic physics has emerged from the experimental and theoretical struggle with its mysteries. We reflect on several of the epic victories in this struggle, and look ahead to where ongoing research might lead us in the understanding of fundamental symmetries and neutrinos. Research supported under DOE grant DE-FG02-97ER41020.

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

    CERN Document Server

    Cremonesi, Oliviero

    2010-01-01

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

  15. Sensitivity of CUORE to Neutrinoless Double-Beta Decay

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-11-23

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

  16. CdWO4 bolometers for Double Beta Decay search

    CERN Document Server

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

    2008-01-01

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

  17. The MAJORANA Neutrinoless Double-Beta Decay Experiment

    International Nuclear Information System (INIS)

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

  18. Total absorption study of beta decays relevant for nuclear applications

    International Nuclear Information System (INIS)

    In this contribution we will present an overview of recent studies of the beta decay of nuclei relevant for the calculation of the decay heat in nuclear reactors as a continuation of the work presented in (1). The measurements are performed using the best available technique to detect the beta feeding probability, the total absorption technique (TAS). In our studies we have combined the TAS technique with the use of a Penning Trap (JYFLTRAP, Univ. of Jyvaeskylae) as a high-resolution isobaric separator in order to guarantee high purity of the sources. A brief summary of the latest results of the measurements using a new segmented total absorption spectrometer, the faced challenges depending of the particular nuclei as well as new developments of the techniques of analysis will be discussed. The impact of the measurements on summation calculations of the decay heat in reactors, and in possible non-proliferation applications will be addressed. Future plans and the development of a new modular TAS detector (DTAS) for the DEcay SPECtroscopy (DESPCE) experiment at FAIR will also presented. (author)

  19. Search for neutrinoless double beta decay in 124Sn

    Directory of Open Access Journals (Sweden)

    Nanal Vandana

    2014-03-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1998-08-01

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

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

    CERN Document Server

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

    2010-01-01

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

  2. Identification of neutron-rich new isotopes and their half-lives

    Energy Technology Data Exchange (ETDEWEB)

    Okano, Kotoyuki; Taniguchi, Akihiro [Kyoto Univ., Kumatori, Osaka (Japan). Research Reactor Inst.

    1996-03-01

    Recently, some new isotopes such as {sup 156}Pm, {sup 155}Nd, {sup 154}Pr, {sup 152}Ce were identified using on-line isotope separation apparatus (KUR-ISOL). The half-lives of these isotopes were several seconds and those of other unknown nuclides are assumed to be around one second or extremely shorter. Detections of {sup 150}La, {sup 153}Ce, {sup 157}Nd etc. have not been succeeded by previous studies. In order to raise the efficiency for identification of short-lived nuclides, it seems essential to remarkably increase the beam strength of KUR-ISOL and to secure its safety operating. A mixed-gas jet method has been developed using a mixed gas of N{sub 2} and He and the beam strength increased by more than one digit. In addition, the exchange over time for gas was shortened by increasing the gas flow volume. Next, various aerosols were tested to select a stable and high efficient ion source and PbI{sub 2} aerosol was chosen as the most suitable one. A 4{pi}{beta}-{gamma}-coinsidence spectrometer with plastic scintillator of 1 mm in depth was constructed and simultaneous measurement for {beta}-ray and {gamma}-ray as well as measurement for a single spectre became possible. Thus identification of {sup 150}La was succeeded by those improvements of KUR-ISOL and the use of 4{pi}{beta}-{gamma}-coinsidence spectrometer. (M.N.)

  3. Neutrinoless double beta decay and heavy sterile neutrinos

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-12-21

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

  5. Systematic study of the single-state dominance in 2 nu beta beta decay transitions

    CERN Document Server

    Civitarese, O

    1999-01-01

    The single-state-dominance hypothesis (SSDH) states that the decay rates of the two-neutrino double-beta decay are governed by a virtual two-step transition connecting the initial and final ground states through the first 1 sup + state, 1 sup + sub 1 , of the intermediate odd-odd nucleus, for those odd-odd nuclei where the 1 sup + sub 1 state is the ground state. To investigate the validity of the SSDH we have performed a systematical theoretical analysis of all known double-beta-decay transitions where the SSDH conditions are fulfilled. The calculations are based on the quasiparticle randon-phase approximation (QRPA) and the results have been obtained by using realistic single-particle bases and realistic interactions. We have studied the double beta sup - decays of sup 1 sup 0 sup 0 Mo, sup 1 sup 1 sup 0 Pd, sup 1 sup 1 sup 4 Cd, sup 1 sup 1 sup 6 Cd and sup 1 sup 2 sup 8 Te and the double electron-capture transitions in sup 1 sup 0 sup 6 Cd and sup 1 sup 3 sup 6 Ce. The analysis shows that the SSDH is real...

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

    CERN Document Server

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

    2014-01-01

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

  7. $\\beta$ - 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...

  8. Competition of $\\beta$-delayed protons and $\\beta$-delayed $\\gamma$ rays in $^{56}$Zn and the exotic $\\beta$-delayed $\\gamma$-proton decay

    CERN Document Server

    Orrigo, S E A; Fujita, Y; Blank, B; Gelletly, W; Agramunt, J; Algora, A; Ascher, P; Bilgier, B; Cáceres, L; Cakirli, R B; Fujita, H; Ganioglu, E; Gerbaux, M; Giovinazzo, J; Grévy, S; Kamalou, O; Kozer, H C; Kucuk, L; Kurtukian-Nieto, T; Molina, F; Popescu, L; Rogers, A M; Susoy, G; Stodel, C; Suzuki, T; Tamii, A; Thomas, J C

    2016-01-01

    Remarkable results have been published recently on the $\\beta$ decay of $^{56}$Zn. In particular, the rare and exotic $\\beta$-delayed $\\gamma$-proton emission has been detected for the first time in the $fp$ shell. Here we focus the discussion on this exotic decay mode and on the observed competition between $\\beta$-delayed protons and $\\beta$-delayed $\\gamma$ rays from the Isobaric Analogue State.

  9. Trapped-ion decay spectroscopy towards the determination of ground-state components of double-beta decay matrix elements

    CERN Document Server

    Brunner, T; Andreoiu, C; Brodeur, M; Delheji, P; Ettenauer, S; Frekers, D; Gallant, A T; Gernhäuser, R; Grossheim, A; Krücken, R; Lennarz, A; Lunney, D; Mücher, D; Ringle, R; Simon, M C; Simon, V V; Sjue, S K L; Zuber, K; Dilling, J

    2013-01-01

    A new technique has been developed at TRIUMF's TITAN facility to perform in-trap decay spectroscopy. The aim of this technique is to eventually measure weak electron capture branching ratios (ECBRs) and by this to consequently determine GT matrix elements of $\\beta\\beta$ decaying nuclei. These branching ratios provide important input to the theoretical description of these decays. The feasibility and power of the technique is demonstrated by measuring the ECBR of $^{124}$Cs.

  10. Trapped-ion decay spectroscopy towards the determination of ground-state components of double-beta decay matrix elements

    Energy Technology Data Exchange (ETDEWEB)

    Brunner, T. [TRIUMF, Vancouver (Canada); Technische Universitaet Muenchen, Physik Department E12, Garching (Germany); Lapierre, A.; Delheji, P.; Grossheim, A.; Ringle, R.; Simon, M.C.; Sjue, S.K.L. [TRIUMF, Vancouver (Canada); Andreoiu, C. [Simon Fraser University, Department of Chemistry, Burnaby (Canada); Brodeur, M. [University of Notre Dame, Department of Physics, Notre Dame, IN (United States); Ettenauer, S.; Gallant, A.T.; Dilling, J. [TRIUMF, Vancouver (Canada); University of British Columbia, Department of Physics and Astronomy, Vancouver (Canada); Frekers, D. [Westfaelische Wilhelms-Universitaet Muenster, Muenster (Germany); Gernhaeuser, R.; Kruecken, R.; Muecher, D. [Technische Universitaet Muenchen, Physik Department E12, Garching (Germany); Lennarz, A. [TRIUMF, Vancouver (Canada); Westfaelische Wilhelms-Universitaet Muenster, Muenster (Germany); Lunney, D. [Universite de Paris Sud, CSNSM-IN2P3-CNRS, Orsay (France); Simon, V.V. [TRIUMF, Vancouver (Canada); Ruprecht-Karls-Universitaet Heidelberg, Fakulaet fuer Physik und Astronomie, Heidelberg (Germany); Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Zuber, K. [Technische Universitaet Dresden, Institut fuer Kern- und Teilchenphysik, Dresden (Germany)

    2013-11-15

    A new technique has been developed at the TRIUMF's TITAN facility to perform in-trap decay spectroscopy. The aim of this technique is to eventually measure weak electron capture branching ratios (ECBRs) and by this to consequently determine GT matrix elements of {beta} {beta} decaying nuclei. These branching ratios provide important input to the theoretical description of these decays. The feasibility and power of the technique is demonstrated by measuring the ECBR of {sup 124}Cs. (orig.)

  11. The MAJORANA DEMONSTRATOR Neutrinoless Double-Beta Decay Experiment

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-06-01

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

  12. The MAJORANA DEMONSTRATOR Neutrinoless Double-Beta Decay Experiment

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-01-01

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

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

    Science.gov (United States)

    Kotila, Jenni; Barea, Jose

    2015-10-01

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

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

    CERN Document Server

    Benato, Giovanni

    2015-01-01

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

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

    International Nuclear Information System (INIS)

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

  16. Neutrinoless Double Beta Decay and Lepton Flavor Violation

    OpenAIRE

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

    2004-01-01

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

  17. LUCIFER: A new technique for Double Beta Decay

    OpenAIRE

    Ferroni, Fernando

    2011-01-01

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

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

    CERN Document Server

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

    2002-01-01

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

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

    CERN Document Server

    Deppisch, Frank F; Huang, Wei-Chih

    2015-01-01

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

  20. Neutron beta decay studies at the Institut Laue-Langevin

    International Nuclear Information System (INIS)

    In the frame of the electroweak Standard Model of particle physics, neutron beta decay is described by only two parameters: the element Vud of the weak quark mixing matrix (CKM matrix) and the ratio λ=gA/gV of the weak coupling constants of the neutron. Experimentally, a larger number of neutron decay parameters are accessible. These are the lifetime and various correlation coefficients between the spins and momenta of the particles involved in neutron decay. Hence, the problem is strongly overdetermined, and many tests going beyond the Standard Model are possible. These comprise tests of the unitarity of the CKM matrix, tests for tensor and scalar admixtures, searches for right-handed currents within the frame of left-right symmetric models, as well as tests of time reversal symmetry. During the past years various groups working in this field have made considerable progress in neutron decay experimentation. In our presentation we shall give a survey on new experiments performed at the Institut Laue-Langevin, Grenoble, France, and on the results concerning the Standard Model

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

  3. Testing the importance of collective correlations in neutrinoless $\\beta\\beta$ decay

    CERN Document Server

    Menéndez, J; Engel, J; Martínez-Pinedo, G; Rodríguez, T R

    2016-01-01

    We investigate the extent to which theories of collective motion can capture the physics that determines the nuclear matrix elements governing neutrinoless double-beta decay. To that end we calculate the matrix elements for a series of isotopes in the full $pf$ shell, omitting no spin-orbit partners. With the inclusion of isoscalar pairing, a separable collective Hamiltonian that is derived from the shell model effective interaction reproduces the full shell-model matrix elements with good accuracy. A version of the generator coordinate method that includes the isoscalar pairing amplitude as a coordinate also reproduces the shell model results well, an encouraging result for theories of collective motion, which can include more single-particle orbitals than the shell model. We briefly examine heavier nuclei relevant for experimental double-beta decay searches, in which shell-model calculations with all spin-orbit partners are not feasible; our estimates suggest that isoscalar pairing also plays a significant ...

  4. Shell Model description of the {beta}{beta} decay of {sup 136}Xe

    Energy Technology Data Exchange (ETDEWEB)

    Caurier, E.; Nowacki, F. [IPHC, IN2P3-CNRS/Universite Louis Pasteur BP 28, F-67037 Strasbourg Cedex 2 (France); Poves, A., E-mail: alfredo.poves@uam.es [Departamento de Fisica Teorica, Universidad Autonoma de Madrid and Instituto de Fisica Teorica, UAM/CSIC, E-28049, Madrid (Spain)

    2012-05-01

    We study in this Letter the double beta decay of {sup 136}Xe with emission of two neutrinos which has been recently measured by the EXO-200 Collaboration. We use the same shell model framework, valence space, and effective interaction that we have already employed in our calculation of the nuclear matrix element (NME) of its neutrinoless double beta decay. Using the quenching factor of the Gamow-Teller operator which is needed to reproduce the very recent high resolution {sup 136}Xe ({sup 3}He, t) {sup 136}Cs data, we obtain a nuclear matrix element M{sup 2{nu}}=0.025 MeV{sup -1} compared with the experimental value M{sup 2{nu}}=0.019(2) MeV{sup -1}.

  5. Calculated masses and half-lives for nuclei in the region 100 less than or equal to Z less than or equal to 110

    International Nuclear Information System (INIS)

    We have calculated nuclear masses and the corresponding α-decay energies O/sub α/ and α half-lives T/sub α/ by use of the folded-Yukawa macroscopic-microscopic model, for nuclei at the end of the peninsula of known elements. We have also calculated, by use of the modified oscillator model, fission half-lives for even-even nuclei with Z between 100 and 110. The results agree well with data in this region, but an interpretation of the experimental data required further and extensive theoretical studies of odd particle effects. 13 references

  6. Deformed shell model results for neutrinoless double beta decay of nuclei in A=60-90 region

    CERN Document Server

    Sahu, R

    2014-01-01

    Nuclear transition matrix elements (NTME) for the neutrinoless double beta decay of $^{70}$Zn, $^{80}$Se and $^{82}$Se nuclei are calculated within the framework of the deformed shell model based on Hartree-Fock states. For $^{70}$Zn, jj44b interaction in $^{2}p_{3/2}$, $^{1}f_{5/2}$, $^{2}p_{1/2}$ and $^{1}g_{9/2}$ space with $^{56}$Ni as the core is employed. However, for $^{80}$Se and $^{82}$Se nuclei, a modified Kuo interaction with the above core and model space are employed. Most of our calculations in this region were performed with this effective interaction. However, jj44b interaction has been found to be better for $^{70}$Zn. After ensuring that DSM gives good description of the spectroscopic properties of low-lying levels in these three nuclei considered, the NTME are calculated. The deduced half-lives with these NTME, assuming neutrino mass is 1 eV, are $9.6 \\times 10^{25}$yr, $1.9 \\times 10^{27}$yr and $1.95 \\times 10^{24}$yr for $^{70}$Zn, $^{80}$Se and $^{82}$Se, respectively.

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

    CERN Document Server

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

    2004-01-01

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

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

    Science.gov (United States)

    Moe, Michael

    2013-04-01

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

  9. 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...

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

    Indian Academy of Sciences (India)

    C Brofferio

    2010-08-01

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

  11. Large-scale shell-model analysis of the neutrinoless $\\beta\\beta$ decay of $^{48}$Ca

    CERN Document Server

    Iwata, Y; Otsuka, T; Utsuno, Y; Menendez, J; Honma, M; Abe, T

    2016-01-01

    We present the nuclear matrix element for the neutrinoless double-beta decay of $^{48}$Ca based on large-scale shell-model calculations including two harmonic oscillator shells ($sd$ and $pf$ shells). The excitation spectra of $^{48}$Ca and $^{48}$Ti, and the two-neutrino double-beta decay of $^{48}$Ca are reproduced in good agreement to experiment. We find that the neutrinoless double-beta decay nuclear matrix element is enhanced by about 30\\% compared to $pf$-shell calculations. This reduces the decay lifetime by almost a factor of two. The matrix-element increase is mostly due to pairing correlations associated with cross-shell $sd$-$pf$ excitations. We also investigate possible implications for heavier neutrinoless double-beta decay candidates.

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

    CERN Document Server

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

    2016-01-01

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

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

    OpenAIRE

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

    2016-01-01

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

  14. Limits on sterile neutrino contributions to neutrinoless double beta decay

    CERN Document Server

    Barea, J; Iachello, F

    2015-01-01

    Nuclear matrix elements (NME) for exchange of arbitrary mass neutrinos are calculated in the interacting boson model (IBM-2). By combining the NME with the phase space factors (PSF), expected half-lives for neutrinos of mass $m_N$ and coupling $U_{eN}$ are estimated. Limits on sterile neutrinos with masses in the eV, keV, MeV-GeV, and TeV range are given.

  15. Recent progress in measuring β half-lives of nuclei approaching the r-process waiting point A = 195

    International Nuclear Information System (INIS)

    Heavy neutron-rich nuclei close to N=126 were produced by fragmentation of a 1A GeV208Pb beam at the FRS at GSI. The β-decay half-lives of 8 nuclides have been determined using a novel numerical analysis method. The comparison of the data with model calculations provides indications on the importance of first-forbidden transitions around A=195. The measured data indicate that the matter flow in the r-process to heavier fissioning nuclei may be faster than previously expected.

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

    Science.gov (United States)

    Barnabé Heider, Marik; Gerda Collaboration

    2012-08-01

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

  17. Data Evaluation for 56Co epsilon + beta+ Decay

    Energy Technology Data Exchange (ETDEWEB)

    Baglin, Coral M.; MacMahon, T. Desmond

    2005-02-28

    Recommended values for nuclear and atomic data pertaining to the {var_epsilon} + {beta}{sup +} decay of {sup 56}Co are provided here, followed by comments on evaluation procedures and a summary of all available experimental data. {sup 56}Co is a radionuclide which is potentially very useful for Ge detector efficiency calibration because it is readily produced via the {sup 56}Fe(p,n) reaction, its half-life of 77.24 days is conveniently long, and it provides a number of relatively strong {gamma} rays with energies up to {approx}3500 keV. The transition intensities recommended here for the strongest lines will be included in the forthcoming International Atomic Energy Agency Coordinated Research Programme document ''Update of X- and Gamma-ray Decay Data Standards for Detector Calibration and Other Applications'', and the analysis for all transitions along with relevant atomic data have been provided to the Decay Data Evaluation Project.

  18. Nab: a precise study of unpolarized neutron beta decay

    Science.gov (United States)

    Pocanic, Dinko; Nab Collaboration

    2015-10-01

    Nab is a program of measurements of unpolarized neutron decays at the Spallation Neutron Source, Oak Ridge, TN. Nab aims to determine a, the e- ν correlation with precision of δa / a =10-3 , and b, the Fierz interference term, with uncertainty δb ~= 3 ×10-3 . The set of available observables overconstrains neutron beta decay in the Standard Model (SM), opening the door to searches for evidence of possible SM extensions. Projected Nab results will lead to a new precise determination of the ratio λ =GA /GV , and to significant reductions in the allowed limits for both right- and left-handed scalar and tensor currents. Alternatively, Nab may detect a discrepancy from SM predictions consistent with certain realizations of supersymmetry. A long asymmetric spectrometer, optimized to achieve the required narrow proton momentum response function, is currently under construction. The apparatus is to be used in follow-up measurements (ABba experiment) of asymmetry observables A and B in polarized neutron decay. Nab is planned for beam readiness in 2016. We discuss the experiment's motivation, expected reach, design and method, and update its status. Work supported by NSF Grants PHY-1126683, 1205833, 1307328, 1506320, and others.

  19. Nuclear-structure aspects of double beta decay

    International Nuclear Information System (INIS)

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

  20. Systematics of half-lives for proton radioactivity

    International Nuclear Information System (INIS)

    Half-life measurements for both ground-state and isomeric transitions in proton radioactivity are systematized by using a semiempirical, one-parameter model based on tunneling through a potential barrier, where the centrifugal and overlapping effects are taken into account within the spherical nucleus approximation. This approach, which has been successfully applied to alpha decay cases covering ∼ 30 orders of magnitude in half-life, has shown, in addition, very adequate at fitting all existing data on partial half-life, T1/2p, of proton emission from nuclei. Nearly 70 measured half-life values have been analysed, and the data could be described by two straight lines relating the pure Coulomb contribution to half life with the quantity Zd(μ0/Qp)1/2 (Zd is the atomic number of the daughter nucleus, μ0 is the reduced mass, and Qp is the total nuclear energy available for decay). These straight lines are shown to correspond to different degrees of deformation, namely, very prolate (δ> approx. 0.1), and other shaped (delta < approx. 0.1) parent nuclei. The goodness in reproducing the data attained in the present systematics allows for half-life predictions for a few possible cases of proton radioactivity not yet experimentally accessed. (author)

  1. Estimations of beta-decay energies through the nuclidic chart by using neural network

    International Nuclear Information System (INIS)

    One of the main characteristics of unstable nuclei is beta-decay energy (Qβ). It is determined by different methods such as beta endpoint measurements, counting in coincidence with annihilation radiation, electron capture (EC)/β+ ratio method, method of gamma absorption with X-ray coincidence. Beta-decay energy is a roughly linear function of atomic and mass numbers. Due to the fact that artificial neural network (ANN) is sufficient for nonlinear function approximation, in this study by using the nuclear masses from Hartree–Fock–BCS method, Qβ values have been obtained by ANN. It is seen that the estimations of the ANN are consistent with the calculated data within some deviation. - Highlights: • Beta decay energy is characteristic of unstable nuclei. • Atomic masses of nuclei can be calculated by using beta decay energy. • Artificial neural network is capable for the estimation of beta decay energy

  2. Beta decays of /sup 126/Cd and /sup 126/In to levels in /sup 126/In and /sup 126/Sn. [J,. pi.

    Energy Technology Data Exchange (ETDEWEB)

    Gartner, M.L.

    1979-01-01

    A study of the beta decays of /sup 126/Cd and /sup 126/In using the TRISTAN on-line isotope separator facility is reported. Gamma-ray singles measurements were made for both decays usng Ge(Li) and LEPS (low energy photon spectrometer) detectors. In addition, gamma--gamma coincidence measurements and gamma multiscale measurements were made for both decays using Ge(Li) detectors. The half-life for /sup 126/Cd was determined to be 0.506 +- 0.015 sec., and the half-lives for the low- and high-spin /sup 126/In isomers were determined to be 1.83 +- 0.11 sec. and 1.96 +- 0.10 sec., respectively. A total of 11 gamma rays were observed in the decay of /sup 126/Cd, and all but one were placed in a level scheme for /sup 126/In. A total of 48 gamma rays were observed in the decay of the low- and high-spin /sup 126/In isomers and all were placed in a level scheme for /sup 126/Sn. Spin and parity assignments were deduced, whenever possible, on the basis of logft values and gamma decay selection rules. The /sup 126/In decay schemes (one has been proposed for each isomer) are compared with earlier decay studies and with results from /sup 124/Sn(t,p)/sup 126/Sn reaction experiments. The systematics associated with the level schemes are discussed and a comparison is made with the nuclear shell model. 49 references.

  3. The Newcomb-Benford law and nuclear half-lives

    International Nuclear Information System (INIS)

    Compete text of publication follows. The satisfaction of the Newcomb-Benford law (a.k.a. Benford's first digit law) is a long standing issue in science, and has interesting mathematical and philosophical consequences. It was identified by Newcomb in 1881 and reinvented later by Benford in 1938. The law states that the distribution of the first digit of numbers taken from various sources like magazines, scientific publications, wealth statistics, etc. . . follows the law Pd = lg (1 + 1/d) (d = 1, 2, ..., 9), where d is the given digit. It was reported recently that the satisfaction of the law was observed in nuclear decay half-life datasets. Based on this fact, it was implied that the law is helpful as a test for nuclear decay models, as well as it can be used to search for new physical phenomena (like self organized criticality) which can be responsible for the satisfaction of the law. The mathematical conundrum of the Newcomb-Benford law has been solved in 2008 for numbers coming from a data set with a given distribution. The 'Benford compliance theorem' uses the Fourier transform of the probability distribution function of the numbers to identify the characteristics of the distribution responsible for the satisfaction of the law. In our work we confirmed that the halflives of radioactive nuclei satisfy the law by using two standard techniques: direct plotting and the 'ones scaling test' method. We also showed that the distribution of the half-life values closely resembles a log-normal distribution stretching through about 54 orders of magnitude. By using the Fourier transform of the distribution function we showed that the numbers with such a distribution automatically satisfy the Newcomb-Benford law, due to the compliance theorem. Thus we concluded that the satisfaction of the law provides no additional clue on whether a nuclear model is valid or not, given it produces a similar distribution of halflives as observed.

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

  6. Progress report on the Los Alamos tritium beta decay experiment

    International Nuclear Information System (INIS)

    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

  7. Improved estimate of the cross section for inverse beta decay

    CERN Document Server

    Ankowski, Artur M

    2016-01-01

    The hypothesis of the conserved vector current, relating the vector weak and isovector electromagnetic currents, plays a fundamental role in quantitative description of neutrino interactions. Despite being experimentally confirmed with great precision, it is not fully implemented in existing calculations of the cross section for inverse beta decay, the dominant mechanism of antineutrino scattering at energies below a few tens of MeV. In this article, I estimate the corresponding cross section and its uncertainty, ensuring conservation of the vector current. While converging to previous calculations at energies of several MeV, the obtained result is appreciably lower and predicts more directional positron production near the reaction threshold. These findings suggest that in the current estimate of the flux of geologically produced antineutrinos the 232Th and 238U components may be underestimated by 6.1 and 3.7%, respectively. The proposed search for light sterile neutrinos using a 144Ce--144Pr source is predi...

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

    CERN Document Server

    Graesser, Michael L

    2016-01-01

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

  9. Cryogenic Double Beta Decay Experiments: CUORE and CUORICINO

    CERN Document Server

    Maruyama, Reina

    2008-01-01

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

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

    Science.gov (United States)

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

    2015-10-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-10-15

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

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

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

    2015-10-01

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

  14. Transition-edge microcalorimeter for tritium beta decay

    International Nuclear Information System (INIS)

    We are conducting a new tritium beta-decay experiment using a cryogenic microcalorimeter. The microcalorimeter consists of a copper foil with an implanted tritium source. The foil is soldered to a thin film gold pad on a silicon wafer that is in thermal contact with an aluminum/silver bilayer transition-edge sensor. The device is voltage biased with current pulses read out using a SQUID magnetometer. The device has been tested with external sources as well as an implanted tritium source. The device is currently too slow to set a meaningful limit on the square of the neutrino mass, but can be made fast enough to set a limit on the order of 10 eV

  15. Beta-Decay Correlations in the LHC Era

    CERN Document Server

    Bodek, Kazimierz

    2016-01-01

    Neutron and nuclear beta decay correlation coefficients are linearly sensitive to the exotic scalar and tensor interactions that are not included in the Standard Model. The proposed experiment will measure simultaneously 11 neutron correlation coefficients ($a$, $A$, $B$, $D$, $H$, $L$, $N$, $R$, $S$, $U$, $V$) where 5 of them ($H$, $L$, $S$, $U$, $V$) were never addressed before. Silicon pixel detectors are considered as promising alternative to multi-wire gas chambers devoted for electron tracking in the original setup. The expected sensitivity limits for $\\epsilon_S$ and $\\epsilon_T$ -- EFT parameters describing the scalar and tensor contributions to be extracted from the transverse electron polarization related coefficients $H$, $L$, $N$, $R$, $S$, $U$, $V$ are discussed.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-10-28

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

  17. Recent results from cosmology and neutrinoless double beta decay

    Science.gov (United States)

    Dell’Oro, Stefano; Marcocci, Simone

    2016-05-01

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

  18. Fission barriers and half-lives of actinides in the quasimolecular shape valley

    Science.gov (United States)

    Royer, G.; Jaffré, M.; Moreau, D.

    2012-10-01

    The energy of actinide nuclei in the fusionlike deformation valley has been determined from a liquid-drop model, taking into account the proximity energy, the mass and charge asymmetries, and the shell and pairing energies. Double-humped potential barriers appear. The saddle point corresponds to the second maximum and to the transition from compact one-body shapes with a deep neck to two touching ellipsoids. The scission point, where the effects of the nuclear attractive forces between the fragments vanish, lies at the end of an energy plateau below the saddle point and corresponds to two well-separated fragments. The kinetic and excitation energies of the fragments come from the energy on this plateau. The shell and pairing effects play a main role to decide the most probable decay path. The heights of the potential barriers roughly agree with the experimental data and the calculated half-lives follow the trend of the experimental values. A shallow third minimum and a third peak appear in specific asymmetric exit channels where one fragment is close to a double magic quasispherical nucleus, while the other one evolves from oblate to prolate shapes.

  19. Radiobiological half-lives for carbon-14 and hydrogen-3 leucine in man

    International Nuclear Information System (INIS)

    In vivo estimates of protein metabolism in many are often made by oral or intravenous administration of leucine or its ∼-ketoacid, ∼-ketoisocaproate, labeled with 14C or 3H. Previous estimates of radiation dose from such tracers have been based on the measurement of 14CO2 in breath. Using measurements of the decay of 3H or 14C leucine from plasma proteins, longer biological half-lives for these compounds were obtained. The estimated total-body radiation absorbed dose is 0.97 mrad/uCi for [1-14C]KIC (or [1-14C]leucine) and 0.11 mrad/+Ci for ]4,5-3H]leucine (or [3H]KIC). Assuming administered doses of 100 μCi each, the total-body radiation absorbed dose is still well within the limits set by the FDA for Radioactive Drug Research Committees. 12 references, 3 figures, 3 tables

  20. Nuclear transparency and double beta decay of molybdenum 100

    International Nuclear Information System (INIS)

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

  1. The half-lives of biological activity of some pesticides in water

    OpenAIRE

    Kyaw Myint Oo,

    2001-01-01

    In the absence of analytical methods, the half-lives of biological activity of pesticides can be estimated by bioassays. To determine the half-lives of biological acivity of pesticides to fish, static bioassays were conducted in the laboratory with ten different formulations of pesticides using Labeo rohita as a bio-indicator. The half-lives of biological activity for ten different pesticides in soft water at pH 7.5 and 27░C, ranged from 4.6 days to 11.8 days. The half-life of biological acti...

  2. Project 8: Determining neutrino mass from tritium beta decay using a frequency-based method

    Energy Technology Data Exchange (ETDEWEB)

    Doe, Peter J.; Kofron, Jared N.; MCBride, Lisa; Robertson, R. G. H.; Rosenberg, Leslie; Rybka, Gray; Doelman, S.; Rogers, Alan E.; Formaggio, Joseph; Furse, Daniel; Oblath, Noah S.; LaRoque, Benjamin; Leber, Michelle; Monreal, Ben; Bahr, Matthew; Asner, David M.; Jones, Anthony M.; Fernandes, Justin L.; VanDevender, Brent A.; Patterson, Ryan B.; Bradley, Rich; Thummler, Thomas

    2013-10-04

    A general description is given of Project 8, a new approach to measuring the neutrino mass scale via the beta decay of tritium. In Project 8, the energy of electrons emitted in beta decay is determined from the frequency of cyclotron radiation emitted as the electrons spiral in a uniform magnetic field

  3. Project 8: Determining neutrino mass from tritium beta decay using a frequency-based method

    CERN Document Server

    Doe, P J; McBride, E L; Robertson, R G H; Rosenberg, L J; Rybka, G; Doelman, S; Rogers, A; Formaggio, J A; Furse, D; Oblath, N S; LaRoque, B H; Leber, M; Monreal, B; Bahr, M; Asner, D M; Jones, A M; Fernandes, J; VanDevender, B A; Patterson, R; Bradley, R; Thuemmler, T

    2013-01-01

    A general description is given of Project 8, a new approach to measuring the neutrino mass scale via the beta decay of tritium. In Project 8, the energy of electrons emitted in beta decay is determined from the frequency of cyclotron radiation emitted as the electrons spiral in a uniform magnetic field.

  4. $\\beta$3p- spectroscopy and P-$\\gamma$ width determination in the decay of $^{31}$Ar

    CERN Multimedia

    We propose to perform a detailed study of the $\\beta$-decay of the dripline nucleus $^{31}$Ar. This will allow a detailed study of the $\\beta$-delayed 3p-decay as well as provide important information on the resonances of $^{30}$S and $^{29}$P, in particular the ratio between the P- and $\\gamma$- partial widths relevant for astrophysics.

  5. The GT resonance revealed in beta sup + -decay using new experimental techniques

    CERN Document Server

    Algora, A; Rubio, B; Taín, J L; Agramunt, J; Blomqvist, J M; Batist, L; Borcea, R; Collatz, R; Gadea, A; Gerl, J; Gierlik, M; aGórska, M; Guilbaud, O; Grawe, H; Hellström, M; Hu, Z; Janas, Z; Karny, M; Kirchner, R; Kleinheinz, P; Liu, W; Martínez, T; Moroz, F; Plochocki, A; Rejmund, M; Roeckl, E; Rykaczewski, K; Shibata, M; Szerypo, J; Wittmann, V

    1999-01-01

    The GT beta decay of sup 1 sup 5 sup 0 Ho has been studied with a Total Absorption Spectrometer (TAS), with an array of 6 Euroball CLUSTER Ge detectors (the CLUSTER CUBE), and with an alpha detector. The three techniques complement each other. The results provide the first observation of an extremely sharp resonance in GT beta decay.

  6. $\\beta$-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.

  7. Novel nuclear structure aspects of the O{nu}{beta}{beta}-decay

    Energy Technology Data Exchange (ETDEWEB)

    Menendez, J; Poves, A [Departamento de Fisica Teorica, and IFT, UAM-CSIC, Universidad Autonoma de Madrid, 28049-Madrid (Spain); Caurier, E; Nowacki, F, E-mail: alfredo.poves@uam.es [IPHC, IN2P3-CNRS/Universite Louis Pasteur, 67037-Strasbourg (France)

    2011-01-01

    We explore the influence of the deformation on the nuclear matrix elements of the neutrinoless double beta decay (NME), concluding that the difference in deformation -or more generally in the amount of quadrupole correlations- between parent and grand daughter nuclei quenches strongly the decay. We correlate these differences with the seniority structure of the nuclear wave functions. In this context, we examine the present discrepancies between the NME's obtained in the framework of the Interacting Shell Model and the Quasiparticle RPA. In our view, part of the discrepancy can be due to the limitations of the spherical QRPA in treating nuclei which have strong quadrupole correlations. We surmise that the NME's in a basis of generalized seniority are approximately model independent, i. e. they are 'universal'.

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

    CERN Document Server

    Rodríguez, Tomás R

    2010-01-01

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

  9. New nuclear decay modes by spontaneous and beta-enhanced emission of heavy ions

    International Nuclear Information System (INIS)

    The analytical variant of the superasymmetric fussion model (ASAFM) is improved to include shell effects in the zero point vibration energy. In this way better agreement with experimental half-lives for 380 β emitters, 14C radioactivity of 222Ra and the spontaneous fission of uranium isotopes is obtained. The lifetimes of trans-lead nuclides in the range 1010-1030s are estimated for more than 150 emitted heavy ions with atomic numbers smaller than 25. The shell structure and the oddeven effects are cleary manifested in these new decay modes. One way to enhance the emission rates for these processes is to use α-decaying precursors populating excited levels from which quantum mechanical tunneling goes faster. (authors)

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

    International Nuclear Information System (INIS)

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

  11. 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 mββ down to 10 meV. To achieve the last goal, collaboration must demonstrate that a background level of 1 count per year per 4 keV per ton of detector is achievable. The University of Tennessee (UT) neutrino group has made a major commitment to the MJD. P.I. accepted the responsibility for one of the major tasks of the experiment, “Materials and Assay Task” which is crucial to the achievement of low background levels required for the experiment. In addition, the UT group is committed to construct, commission, and operate the MJD active veto system. Those activities were supported by NP-DOE via program funding for “Search for the Neutrino Less Double Beta Decay” at the University

  12. 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.)

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

    CERN Document Server

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

    2010-01-01

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

  14. Stellar $\\beta^{\\pm}$ decay rates of iron isotopes and its implications in astrophysics

    OpenAIRE

    Nabi, Jameel-Un

    2014-01-01

    $\\beta$-decay and positron decay are believed to play a consequential role during the late phases of stellar evolution of a massive star culminating in a supernova explosion. Recently the microscopic calculation of weak-interaction mediated rates on key isotopes of iron was introduced using the proton-neutron quasiparticle random phase approximation (pn-QRPA) theory with improved model parameters. Here I discuss in detail the improved calculation of $\\beta^{\\pm}$ decay rates for iron isotopes...

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

    International Nuclear Information System (INIS)

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

  16. Review of Russian language studies on radionuclide behaviour in agricultural animals: biological half-lives

    International Nuclear Information System (INIS)

    Extensive studies on transfer of radionuclides to animals were carried out in the USSR from the 1950s. Few of these studies were published in the international refereed literature or taken into account in international reviews. This paper continues a series of reviews of Russian language literature on radionuclide transfer to animals, providing information on biological half-lives of radionuclides in various animal tissues. The data are compared, where possible, with those reported in other countries. The data are normally quantified using a single or double exponential accounting for different proportions of the loss. For some products, such as milk, biological half-lives tend to be rapid at 1–3 d for most radionuclides and largely described by a single exponential. However, for other animal products biological half-lives can vary widely as they are influenced by many factors such as the age and size of the animal. Experimental protocols, such as the duration of the study, radionuclide administration and/or sample collection protocol also influence the value of biological half-lives estimated. - Highlights: • The data on biological half-lives from Russian language literature were reviewed. • Radionuclides with the shortest half-lives in animals are those which accumulate in soft tissues. • Short term behaviour is affected by the form in which radionuclides are administered. • There is a tendency for more rapid radionuclide turnover in younger animals

  17. Beta decay far from stability and the decay heat of nuclear reactors

    International Nuclear Information System (INIS)

    First results of a second generation microscopic calculation which we denote by KGM, in contrast to the older KMO calculations (which were actually done in 1981), are shown. It is seen that the new calculations which use an RPA approach treating the odd particle by perturbation theory, can give an improved description of the half-lives, particularly also in the chromium to cobalt region, where some systematic deviation seemed to be present. (orig./BBOE)

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

    International Nuclear Information System (INIS)

    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

  19. Neutrinoless double positron decay and positron emitting electron capture in the interacting boson model

    CERN Document Server

    Barea, J; Iachello, F

    2015-01-01

    Neutrinoless double-$\\beta$ decay is of fundamental importance for determining the neutrino mass. Although double electron ($\\beta^-\\beta^-$) decay is the most promising mode, in very recent years interest in double positron ($\\beta^+\\beta^+$) decay, positron emitting electron capture ($EC\\beta^+$), and double electron capture ($ECEC$) has been renewed. We present here results of a calculation of nuclear matrix elements for neutrinoless double-$\\beta^+$ decay and positron emitting electron capture within the framework of the microscopic interacting boson model (IBM-2) for $^{58}$Ni, $^{64}$Zn, $^{78}$Kr, $^{96}$Ru, $^{106}$Cd, $^{124}$Xe, $^{130}$Ba, and $^{136}$Ce decay. By combining these with a calculation of phase space factors we calculate expected half-lives.

  20. On the spectrum of secondary electrons emitted during nuclear $\\beta^{-}$-decay in few-electron atoms

    CERN Document Server

    Frolov, Alexei M

    2015-01-01

    Ionization of light atoms and ions during nuclear $\\beta^{-}$-decay is considered. We determine the velocity/momentum spectrum of secondary electrons emitted during nuclear $\\beta^{-}$-decay in one-electron tritium atom. The same method can be applied to describe velocity/momentum distributions of secondary electrons emitted from $\\beta^{-}$-decaying few-electron atoms and molecules.

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

    CERN Document Server

    Kortelainen, M

    2003-01-01

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

  2. Quadrupolar correlations and deformation effect on two neutrino $\\varepsilon \\beta ^{+}$ and $\\varepsilon \\varepsilon $ modes of $^{156}$Dy isotope

    OpenAIRE

    Rath, P. K.; R. Chandra; Singh, S; Raina, P. K.; Hirsch, J. G.

    2009-01-01

    The two-neutrino positron double-$\\beta $ decay modes of $^{156}$Dy isotope are studied in the Projected Hartree-Fock-Bogoliubov framework for the $0^{+}\\to 0^{+}$ transition. Theoretically calculated half-lives of electron-positron conversion and double-electron capture modes are presented. The effect of the quadrupolar deformation on nuclear transition matrix element $M_{2\

  3. 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.

  4. Theoretical and Experimental Considerations for Neutrinoless Double Beta Decay

    CERN Document Server

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

    2008-01-01

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

  5. Tritium $\\beta$-decay in chiral effective field theory

    CERN Document Server

    Baroni, A; Kievsky, A; Marcucci, L E; Schiavilla, R; Viviani, M

    2016-01-01

    We evaluate the Fermi and Gamow-Teller (GT) matrix elements in tritium \\beta-decay by including in the charge-changing weak current the corrections up to one loop recently derived in nuclear chiral effective field theory (\\chi EFT). The trinucleon wave functions are obtained from hyperspherical-harmonics solutions of the Schrodinger equation with two- and three-nucleon potentials corresponding to either \\chi EFT (the N3LO/N2LO combination) or meson-exchange phenomenology (the AV18/UIX combination). We find that contributions due to loop corrections in the axial current are, in relative terms, as large as (and in some cases, dominate) those from one-pion exchange, which nominally occur at lower order in the power counting. We also provide values for the low-energy constants multiplying the contact axial current and three-nucleon potential, required to reproduce the experimental GT matrix element and trinucleon binding energies in the N3LO/N2LO and AV18/UIX calculations.

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

    Science.gov (United States)

    Pattavina, Luca

    2014-09-01

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

  7. The half-lives of sup(26m)Al, 34Cl, sup(38m)K

    International Nuclear Information System (INIS)

    The half-lives of sup(26m)Al, 34Cl and sup(38m)K have been measured with isotopically pure samples prepared with an on-line isotope separator. Emitted #betta#+ particles were observed with a large-solid-angle, high-efficiency, low-background gas proportional counter, from which signals were multiscaled. The counting electronics had a well-defined non-extendable dead time. Each sample decay curve was individually corrected for dead time before being summed with other accumulated data, no pile-up corrections being necessary. The analysis procedure was tested on hypothetical data. The effect of contaminant isobars on the resultant half-lives has been investigated. Our half-life results are sup(26m)Al: 6346.2 +- 2.6 ms, 34Cl: 1527.7 +- 2.2 ms and sup(38m)K: 924.2 +- 0.3 ms. The quoted uncertainties include - for the first time - explicit provision for all possible contaminants. (orig.)

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

    Directory of Open Access Journals (Sweden)

    Alexander Merle

    2007-01-01

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

  9. Beta-delayed gamma decay of 26P: Possible evidence of a proton halo

    CERN Document Server

    Pérez-Loureiro, D; Bennett, M B; Liddick, S N; Bowe, A; Brown, B A; Chen, A A; Chipps, K A; Cooper, N; Irvine, D; McNeice, E; Montes, F; Naqvi, F; Ortez, R; Pain, S D; Pereira, J; Prokop, C J; Quaglia, J; Quinn, S J; Sakstrup, J; Santia, M; Schwartz, S B; Shanab, S; Simon, A; Spyrou, A; Thiagalingam, E

    2016-01-01

    Background: Measurements of $\\beta$ decay provide important nuclear structure information that can be used to probe isospin asymmetries and inform nuclear astrophysics studies. Purpose: To measure the $\\beta$-delayed $\\gamma$ decay of $^{26}$P and compare the results with previous experimental results and shell-model calculations. Method: A $^{26}$P fast beam produced using nuclear fragmentation was implanted into a planar germanium detector. Its $\\beta$-delayed $\\gamma$-ray emission was measured with an array of 16 high-purity germanium detectors. Positrons emitted in the decay were detected in coincidence to reduce the background. Results: The absolute intensities of $^{26}$P $\\beta$-delayed $\\gamma$-rays were determined. A total of six new $\\beta$-decay branches and 15 new $\\gamma$-ray lines have been observed for the first time in $^{26}$P $\\beta$-decay. A complete $\\beta$-decay scheme was built for the allowed transitions to bound excited states of $^{26}$Si. $ft$ values and Gamow-Teller strengths were a...

  10. Beta decay of fission products for the non-proliferation and decay heat of nuclear reactors

    International Nuclear Information System (INIS)

    issue of nuclear safety. In this thesis, we present an experimental work which aims to measure the properties of beta decay of fission products important to the non-proliferation and reactor decay heat. First steps using the technique of Total Absorption Gamma-ray Spectroscopy (TAGS) were carried on at the radioactive beam facility of the University of Jyvaskyla. We will present the technique used, the experimental setup and part of the analysis of this experiment. (author)

  11. Search for $\\beta^+$EC and ECEC processes in $^{112}$Sn and $\\beta^-\\beta^-$ decay of $^{124}$Sn to the excited states of $^{124}$Te

    CERN Document Server

    Barabash, A S; Nachab, A; Konovalov, S I; Vanyushin, I A; Umatov, V I

    2008-01-01

    Limits on $\\beta^+$EC and ECEC processes in $^{112}$Sn and on $\\beta^-\\beta^-$ decay of $^{124}$Sn to the excited states of $^{124}$Te have been obtained using a 380 cm$^3$ HPGe detector and an external source consisting of natural tin. A limit with 90% C.L. on the $^{112}$Sn half-life of $0.92\\times 10^{20}$ y for the ECEC(0$\

  12. Analysis of super-allowed Fermi beta-decay

    International Nuclear Information System (INIS)

    Analysis of tile Jπ = 0+ → 0+ super-allowed Fermi transitions within isospin triplets is limited in the precision of its outcome not by the accuracy of the experimental input data nor by the confidence with which the radiative corrections can be applied but by knowledge of the nuclear mismatch: the subversion of the isospin symmetry along the multiplets by the charge-dependence of the forces, both Coulomb and specifically nuclear. Theoretical estimates of the mismatch differ considerably from author to author, their direct application results in clear violation of tile hypothesis of conservation of the vector current and clear inconsistency with unitarity of the Cabibbo-Kobayashi-Maskawa matrix. This paper pursues and elaborates the previous suggestion that, in these unsatisfactory circumstances, the best procedure is to look to the experimental data themselves to determine and eliminate the mismatch by appropriate extrapolation to Z=O. This is done: (i) without any prior correction for mismatch; (ii) after correction for the full theoretical mismatch; (iii) after correction for case-to-case fluctuations in the theoretical mismatch. These three procedures are individually statistically satisfactory and mutually consistent in their extrapolation to Z = 0 despite the variety of the theoretical mismatches on which, in varying degrees, they are based. The resultant unitarity test for the CKM matrix is IVudI2 + IVusI2 + IVubI2 = 1.0003 ± 0.0014. The associated value for the operational vector coupling constant is: Gv* / (hc)3 = (1.15155±0.00064) x 10-5 GeV-2. If unitarity of the CKM matrix is alternatively assumed one may conclude, from a similar analysis, that the mean charge of the fermionic fields between which beta-decay takes place is Q-bar = 0.172±0.060 and that, at the 90% confidence level, bF -3 were bF is the relative effective scalar coupling constant. Neutron decay is also discussed, with the provisional recommendations: GA*/(hc)3 (1.4557±0.0051) x 10

  13. a Measurement of the Asymmetry Parameter for Argon -35 Beta-Decay as a Test of the Conserved Vector Current Hypothesis

    Science.gov (United States)

    Converse, Alexander Milovan

    The spatial asymmetry of positrons emitted parallel and antiparallel to the spin axis of a polarized sample of ^{35}Ar has been measured. The measured asymmetry parameter for the mixed Fermi--Gamow - Teller decay ^{35}Ar( beta^+)^{35}Cl is A_0 = 0.427(23). This agrees with the value predicted by the Standard Model, A _0^{rm theory} = 0.4302(86). The Standard Model prediction assumes vector-axial vector couplings and the validity of the conserved vector current hypothesis; the vector coupling strength is derived from comparative half-lives of pure Fermi 0^+to0^+ transitions, and the ratio of axial vector to vector coupling strengths is calculated using the ^ {35}Ar comparative half-life. In the measurement, polarized ^{35}Ar was created by bombarding a Cl_2 target with 68% polarized 9.2 MeV protons. Positrons emitted at 0^circ and 180 ^circ with respect to the ^{35}Ar polarization axis were observed with DeltaE-E plastic scintillator detectors. The ^{35}Ar polarization was determined from the asymmetry of positrons emitted in the decays ^{35}Ar( beta^+)^{35}Cl ^*, which were identified by the observation of coincident gamma - rays in pure Ge detectors. The decay to the first excited state of ^{35}Cl is pure Gamow - Teller, so its asymmetry parameter may be derived from angular momentum coupling arguments without reference to the Standard Model. The relative uncertainty in this measurement, DeltaA_0 /A_0 = 5.4%, is the quadratic sum of the statistical error, 5.4%, and systematic errors, 0.5%. In light of published measurements of the neutron asymmetry parameter, which are accurate to 1.5% and disagree with the Standard Model prediction by more than 2 sigma, it might be worthwhile to repeat the measurement of the ^{35}Ar ground state asymmetry parameter to obtain statistical precision of <2%.

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

    International Nuclear Information System (INIS)

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

  15. 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.

  16. Beta decay of 252Cf on the way to scission from the exit point

    CERN Document Server

    Pomorski, K; Quentin, P

    2015-01-01

    Upon increasing significantly the nuclear elongation, the beta-decay energy grows. This paper investigates within a simple yet partly microscopic approach, the transition rate of the beta decay of the 252Cf nucleus on the way to scission from the exit point for a spontaneous fission process. A rather crude classical approximation is made for the corresponding damped collective motion assumed to be one dimensional. Given these assumptions, we only aim in this paper at providing the order of magnitudes of such a phenomenon. At each deformation the energy available for beta decay, is determined from such a dynamical treatment. Then, for a given elongation, transition rates for the allowed (Fermi) beta decay are calculated from pair correlated wave functions obtained within a macroscopic-microscopic approach and then integrated over the time corresponding to the whole descent from exit to scission. The results are presented as a function of the damping factor (inverse of the characteristic damping time) in use in...

  17. Detection System for Neutron $\\beta$ Decay Correlations in the UCNB and Nab experiments

    CERN Document Server

    Broussard, L J; Adamek, E R; Baeßler, S; Birge, N; Blatnik, M; Bowman, J D; Brandt, A E; Brown, M; Burkhart, J; Callahan, N B; Clayton, S M; Crawford, C; Cude-Woods, C; Currie, S; Dees, E B; Ding, X; Fomin, N; Frlez, E; Fry, J; Gray, F E; Hasan, S; Hickerson, K P; Hoagland, J; Holley, A T; Ito, T M; Klein, A; Li, H; Liu, C -Y; Makela, M F; McGaughey, P L; Mirabal-Martinez, J; Morris, C L; Ortiz, J D; Pattie, R W; Penttilä, S I; Plaster, B; Počanić, D; Ramsey, J C; Salas-Bacci, A; Salvat, D J; Saunders, A; Seestrom, S J; Sjue, S K L; Sprow, A P; Tang, Z; Vogelaar, R B; Vorndick, B; Wang, Z; Wei, W; Wexler, J; Wilburn, W S; Womack, T L; Young, A R

    2016-01-01

    We describe a detection system designed for precise measurements of angular correlations in neutron $\\beta$ decay. The system is based on thick, large area, highly segmented silicon detectors developed in collaboration with Micron Semiconductor, Ltd. The prototype system meets specifications for $\\beta$ electron detection with energy thresholds below 10 keV, energy resolution of $\\sim$3 keV FWHM, and rise time of $\\sim$50 ns with 19 of the 127 detector pixels instrumented. Using ultracold neutrons at the Los Alamos Neutron Science Center, we have demonstrated the coincident detection of $\\beta$ particles and recoil protons from neutron $\\beta$ decay. The fully instrumented detection system will be implemented in the UCNB and Nab experiments, to determine the neutron $\\beta$ decay parameters $B$, $a$, and $b$.

  18. Bond Rupture following C14 and T3 Beta Decay

    International Nuclear Information System (INIS)

    As a result of nuclear transformations an atom acquires a recoil energy, and a portion of this energy becomes associated with the chemical bond or bonds joining the activated atom to the molecule. Usually sufficient energy is deposited in these bonds to permit the activated atom to dissociate from the remainder of the molecule. Bond-rupture, however, usually does not occur with 100% efficiency. Momentum transfer to an atom in a molecule (internal excitation and bond-rupture) have been discussed recently with reference to activation of atoms joined to a molecule by only one bond. Additional molecules are considered in the present paper, and data presented on the net recoil energy required for bond- rupture, the rotational and vibrational excitation energies received by the rupturing bond, the internal energy of the radical originally bonded to the activated atom, and the kinetic energy of the radicals. It is shown that, on the average, the recoil energy that must be acquired by the activated atom in order to rupture from the molecule is about 25% greater than that calculated assuming a pseudo-diatomic molecule. Data are also presented for certain C14 and T3 beta-decay recoil processes. For C14O2 it is calculated that a net N14 recoil energy s 1.92 times the ON-O+ bond dissociation energy is required for bond-rupture. Since the NO+2 product may possess about 0.6 to 1.0 eV of electronic excitation energy, the ON-O+ bond dissociation energy is not uniquely defined. The calculated value of non-bond-rupture is 73 - 87% in good agreement with the reported experimental value of 81%. Similar data are also presented for such molecules as CH3T, C2H5T, C3H7T, and C142H6. (author)

  19. Sense and sensitivity of double beta decay experiments

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

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

    CERN Document Server

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

    2012-01-01

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

  2. Molecular effects in the neutrino mass determination from beta-decay of the tritium molecule

    International Nuclear Information System (INIS)

    Molecular final state energies and transition probabilities have been computed for beta-decay of the tritium molecule. The results are of sufficient accuracy to make a determination of the electron neutrino rest mass with an error not exceeding a few tenths of an electron volt. Effects of approximate models of tritium beta-decay on the neutrino mass determination are discussed. 14 refs., 3 figs., 1 tab

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

    CERN Document Server

    Civitarese, O

    2003-01-01

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

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

    CERN Document Server

    Menéndez, J

    2016-01-01

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

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

    CERN Document Server

    Klapdor-Kleingrothaus, Hans Volker; Smirnov, Yu A

    2001-01-01

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

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

    CERN Document Server

    Mahajan, Namit

    2015-01-01

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

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

    OpenAIRE

    Zuber, K.

    2005-01-01

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

  8. Measurement of the beta beta Decay Half-Life of Te-130 with the NEMO-3 Detector

    OpenAIRE

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

    2011-01-01

    We report results from the NEMO-3 experiment based on an exposure of 1275 days with 661 g of Te-130 in the form of enriched and natural tellurium foils. The beta beta decay rate of Te-130 is found to be greater than zero with a significance of 7.7 standard deviations and the half-life is measured to be T-1/2(2v)=[7.0 +/- 0.9(stat) +/- 1: 1(syst)] x 10(20) yr. This represents the most precise measurement of this half- life yet published and the first real-time observation of this decay.

  9. Heavy element and actinide decay data: UKHEDD-2 data files

    International Nuclear Information System (INIS)

    A re-evaluation has been made of the decay data for 126 heavy elements and actinides of direct application in nuclear fuel cycle calculations. Computer-based data files have been produced in ENDF/B-VI format, including lists of the references used to produce the proposed decay schemes and comments that identify their inadequacies. These evaluated data include half-lives, average decay energies, branching ratios, alpha, beta and gamma-ray energies and emission probabilities, internal conversion coefficients, spontaneous fission decay data and all associated uncertainties. (author)

  10. Influence of pairing in double beta decay of48Ca

    Indian Academy of Sciences (India)

    Prianka Roy; Shashi K Dhiman

    2010-03-01

    Two-neutrino decay matrix elements and half-life of 48Ca are calculated after including neutron–proton pairing correlations in projected Hartree–Fock–Bogoliubov (PHFB) formalism. The GT matrix elements in 2 decay are reduced due to broader smearing of Fermi surfaces. Half-life results for 2 decay of 48Ca with np pairing are better than without pairing.

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

    OpenAIRE

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

    2007-01-01

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

  12. Generalized solutions of the Dirac equation, W bosons, and beta decay

    CERN Document Server

    Okninski, Andrzej

    2016-01-01

    We study the 7x7 Hagen-Hurley equations describing spin 1 particles. We split these equations, in the interacting case, into two Dirac equations with non-standard solutions. It is argued that these solutions describe decay of a virtual W boson in beta decay.

  13. Spectrum of secondary electrons emitted during the nuclear $\\beta^{-}$-decay of the tritium atom

    CERN Document Server

    Frolov, Alexei M

    2015-01-01

    We discuss ionization of the final ${}^{3}$He$^{+}$ ion during the nuclear $\\beta^{-}$-decay of the tritium atom. The velocity spectrum of secondary electrons emitted during such a decay is derived in the explicit form. Our method allows one to determine both the relative and absolute probabilities of formation of the final states with certain velocities of secondary electrons.

  14. CP-Violation in Neutrino Oscillations from EC/{beta}{sup +} decaying ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Espinoza, Catalina [Centre for Theoretical Particle Physics, IST, Technical University of Lisbon, Av. Rovisco Pais 1, 1049-001 Lisboa (Portugal)

    2012-08-15

    We discuss the separation of unknown neutrino properties by means of the energy dependence of the oscillation probability and we consider an hybrid setup which combines the electron capture and the {beta}{sup +} decay from the same radioactive proton-rich ion with the same boost. We conclude that the combination of the two decay channels, with different neutrino energies, achieves remarkable results.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1993-05-10

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

  16. Searches for heavy neutrinos from 35S, 14C, and 63Ni beta decay

    International Nuclear Information System (INIS)

    We have searched for the effect of a neutrino of mass 17 keV/c2 in the beta decay of 35S with an apparatus incorporating a high resolution solid state detector and a super conducting solenoid. The experimental mixing probability of the 17keV neutrino is consistent with zero. The experimental sensitivity is verified by measurements with a mixed source of 35S and 14C, which artificially produces a distortion in the beta spectrum similar to that expected from the massive neutrino. Recently, we have performed similar searches in the beta decay of 14C and 63Ni. Results of these new measurements will be presented

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

    Energy Technology Data Exchange (ETDEWEB)

    Dolinski, M J

    2008-09-24

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

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

  20. 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.

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

    Science.gov (United States)

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

    2000-04-01

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

  2. 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.)

  3. 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.

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

    CERN Document Server

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

    2015-01-01

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

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

    CERN Document Server

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

    2004-01-01

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

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

    CERN Document Server

    Kovalenko, S; Simkovic, F

    2013-01-01

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

  7. Particle-Vibration Coupling Effect on the β Decay of Magic Nuclei

    OpenAIRE

    Niu, Y.; Niu, Z; Colo, G.; E. Vigezzi(Dipartimento di Fisica and INFN, Milano, Italy)

    2015-01-01

    Nuclear $\\beta$-decay in magic nuclei is investigated, taking into account the coupling between particle and collective vibrations,on top of self-consistent random phase approximation calculations based on Skyrme density functionals. The low-lying Gamow-Teller strength is shifted downwards and at times becomes fragmented; as a consequence, the $\\beta$-decay half-lives are reduced due to the increase of the phase space available for the decay. In some cases, this leads to a very good agreement...

  8. Observation of Doppler broadening in $\\beta$-delayed proton-$\\gamma$ decay

    CERN Document Server

    Schwartz, S B; Bennett, M B; Liddick, S N; Perez-Loureiro, D; Bowe, A; Chen, A A; Chipps, K A; Cooper, N; Irvine, D; McNeice, E; Montes, F; Naqvi, F; Ortez, R; Pain, S D; Pereira, J; Prokop, C; Quaglia, J; Quinn, S J; Sakstrup, J; Santia, M; Shanab, S; Simon, A; Spyrou, A; Thiagalingam, E

    2015-01-01

    Background: The Doppler broadening of $\\gamma$-ray peaks due to nuclear recoil from $\\beta$-delayed nucleon emission can be used to measure the energies of the nucleons. This method has never been tested using $\\beta$-delayed proton emission or applied to a recoil heavier than $A=10$. Purpose: To test and apply this Doppler broadening method using $\\gamma$-ray peaks from the $^{26}$P($\\beta p\\gamma$)$^{25}$Al decay sequence. Methods: A fast beam of $^{26}$P was implanted into a planar Ge detector, which was used as a $^{26}$P $\\beta$-decay trigger. The SeGA array of high-purity Ge detectors was used to detect $\\gamma$ rays from the $^{26}$P($\\beta p\\gamma$)$^{25}$Al decay sequence. Results: Radiative Doppler broadening in $\\beta$-delayed proton-$\\gamma$ decay was observed for the first time. The Doppler broadening analysis method was verified using the 1613 keV $\\gamma$-ray line for which the proton energies were previously known. The 1776 keV $\\gamma$ ray de-exciting the 2720 keV $^{25}$Al level was observed...

  9. First measurement of several $\\beta$-delayed neutron emitting isotopes beyond N=126

    CERN Document Server

    Caballero-Folch, R; Agramunt, J; Algora, A; Ameil, F; Arcones, A; Ayyad, Y; Benlliure, J; Borzov, I N; Bowry, M; Calvino, F; Cano-Ott, D; Cortés, G; Davinson, T; Dillmann, I; Estrade, A; Evdokimov, A; Faestermann, T; Farinon, F; Galaviz, D; García, A R; Geissel, H; Gelletly, W; Gernhäuser, R; Gómez-Hornillos, M B; Guerrero, C; Heil, M; Hinke, C; Knöbel, R; Kojouharov, I; Kurcewicz, J; Kurz, N; Litvinov, Y; Maier, L; Marganiec, J; Marketin, T; Marta, M; Martínez, T; Martínez-Pinedo, G; Montes, F; Mukha, I; Napoli, D R; Nociforo, C; Paradela, C; Pietri, S; Podolyák, Zs; Prochazka, A; Rice, S; Riego, A; Rubio, B; Schaffner, H; Scheidenberger, Ch; Smith, K; Sokol, E; Steiger, K; Sun, B; Taín, J L; Takechi, M; Testov, D; Weick, H; Wilson, E; Winfield, J S; Wood, R; Woods, P; Yeremin, A

    2015-01-01

    The $\\beta$-delayed neutron emission probabilities of neutron rich Hg and Tl nuclei have been measured together with $\\beta$-decay half-lives for 20 isotopes of Au, Hg, Tl, Pb and Bi in the mass region N$\\gtrsim$126. These are the heaviest species where neutron emission has been observed so far. These measurements provide key information to evaluate the performance of nuclear microscopic and phenomenological models in reproducing the high-energy part of the $\\beta$-decay strength distribution. In doing so, it provides important constraints to global theoretical models currently used in $r$-process nucleosynthesis.

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

    International Nuclear Information System (INIS)

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

  11. Sum rules for the gross theory of beta-decay

    International Nuclear Information System (INIS)

    This paper presents a method for relating the β-decay strength function with the nuclear force. This relation is obtained as sum rules for the one-particle strength function which appears in the gross theory of β-decay. They sum rules were calculated for the Gamow-Teller transition with some central potentials and the Hamada-Johnston potential. The sum-rule values were found to depend strongly on the assumed nuclear force

  12. Time reversal tests in nuclear and neutron beta decay

    International Nuclear Information System (INIS)

    Motivation for time reversal violation studies in nuclear and neutron weak decay is discussed with an emphasis on searches for the exotic tensor and scalar weak interaction. The results of the experiment with polarized 8Li are updated. A new experiment with the aim to determine the transverse polarization of electrons emitted by free, polarized neutrons, is proposed. A facility for neutron decay studies with polarized cold neutrons is under construction at the spallation source SINQ-PSI

  13. Limit on Neutrinoless {\\beta}{\\beta} Decay of Xe-136 from the First Phase of KamLAND-Zen and Comparison with the Positive Claim in Ge-76

    CERN Document Server

    ,

    2012-01-01

    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 Xe-136. We obtain a lower limit for the neutrinoless double-beta decay half-life of T_{1/2}^{0{\

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-02-24

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

  15. Long ecological half-lives in seminatural systems. Annual report 1996. Project plan 1997

    International Nuclear Information System (INIS)

    The EKO-2 project, 'Long ecological half-lives in semi-natural systems', consists of three subprojects; sheep grazing on uncultivated pasture, mushrooms and freshwater fish. The main aim is to identify the contribution from semi-natural systems, by determining ecological half-lives for specific foodstuffs from these areas, and thus determine dose to man. In the three ongoing projects we have produced or used data for 8-10 years after the Chernobyl accident. The time series have been very necessary for predicting ecological half-lives for radiocesium and radiostrontium. Unfortunately, the data for radiostrontium have been very scarce. The recovery of Nordic ecosystems from contamination by 137Cs originating from the Chernobyl accidents is gradually slowing down, at the same time as areas vary widely in susceptibility and recovery rates. The projects have given us useful understanding of the mechanisms governing the transfer of radionuclides, and more knowledge about typical Nordic ecosystems. The soil - vegetation - sheep - system is being studied in five countries; Iceland, the Faeroe Islands, Denmark, Sweden and Norway. Co-ordinated collection of soil, vegetation and meet samples have been performed every year since 1990. After a slow start in 1994, many results from the project 'Transfer of radiocesium via mushrooms to roe deer and man (the forest project)' have been published during 1996. Questionnaires have been implemented in Sweden, Denmark and Finland, in Sweden and Denmark with focus on mushrooms, and a more thorough investigation in Finland on natural products for consumption. The main aim in the project 'Ecological half-lives in limnic ecosystems' has been to investigate the processes and mechanisms leading to radiocesium being easily available for uptake in e.g. fish. Systematic collection of data has enabled the construction of a GIS system to show fallout levels of 137Cs, influence from catchment areas, and prediction of 137Cs in fish. (EG)

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

    Science.gov (United States)

    Barabash, A. S.

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

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

    CERN Document Server

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

    2011-01-01

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

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

    CERN Document Server

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

    2009-01-01

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

  19. Two-neutrino double decay of 96Zr to excited

    Indian Academy of Sciences (India)

    J Singh; R Chandra; P K Raina; P K Rath

    2005-09-01

    The two-neutrino double beta decay of 96Zr isotope for 0+ → 2+ transition has been studied in the PHFB model. In our earlier work, the reliability of the intrinsic wave functions of 96Zr and 96Mo isotopes has been established by obtaining an overall agreement between a number of theoretically calculated spectroscopic properties as well as half-lives of 2 decay for 0+ → 0+ transition and the available experimental data. In the present work, the half-life of 2 decay for 0+ → 2+ transition $T_{1/2}^{2} (0+ → 2+) has been calculated using the same set of intrinsic wave functions.

  20. Half-lives of ground and isomeric states in 97Cd and the astrophysical origin of 96Ru

    International Nuclear Information System (INIS)

    First experimental evidence for a high-spin isomer (25/2+) in 97Cd, a waiting point in the astrophysical rapid proton capture process, is presented. The data were obtained in β-decay studies at NSCL using the new RF Fragment Separator system and detecting β-delayed protons and β-delayed γ rays. Decays from ground and isomeric states were disentangled, and proton emission branches were determined for the first time. We find half-lives of 1.10(8) s and 3.8(2) s, and β-delayed proton emission branches of 12(2)% and 25(4)% were deduced for the ground and isomeric states, respectively. With these results, the nuclear data needed to determine an rp-process contribution to the unknown origin of solar 96Ru are in place. When the new data are included in astrophysical rp-process calculations, one finds that an rp-process origin of 96Ru is unlikely.

  1. The Heidelberg-Moscow double beta decay experiment with enriched sup 76 Ge. First result

    Energy Technology Data Exchange (ETDEWEB)

    Balysh, A.; Belyaev, S.T.; Demehin, A.; Gurov, A.; Kondratenko, I.; Lebedev, V.I. (Max-Planck-Inst. fuer Kernphysik, Heidelberg (Germany)); Beck, M.; Bockholt, J.; Echternach, J.; Heusser, G.; Hirsch, M.; Klapdor-Kleingrothaus, H.V.; Maier, B.; Petry, F.; Piepke, A.; Schmidt-Rohr, U.; Strecker, H.; Zuber, K. (Kurchatov Inst., Moscow (USSR)); Mueller, A. (Ist. Nazionale di Fisica Nucleare, Assergi (Italy))

    1992-06-04

    The status of the Heidelberg-Moscow {beta}{beta}-experiment using isotopically enriched {sup 76}Ge is reported. The results of 14.8 mol yr (or 1.29 kg yr) of operation are presented. From these data a new half life time for the {beta}{beta}0{nu}-decay of {sup 76}Ge to the ground state of {sup 76}Se of T{sub 1/2}>1.4(2.5)x10{sup 24} yr with 90% (68%) CL can be deduced. For a possible neutrinoless decay to the first excited state a half life of 4.3(8.2)x10{sup 23} yr can be excluded with 90% (68%) CL. (orig.).

  2. Experimental study on neutrinoless double beta decay of 92Mo

    International Nuclear Information System (INIS)

    An experiment for the detection of 0νβ+/EC in 92Mo nuclei has been carried out with a newly developed scintillating crystal, CaMoO4, surrounded by CsI(Tl) crystals. We study the background events inside the event selection window for 0νβ+/EC decays of CaMoO4 detector. The 92Mo 0νβ+/EC decay half-life limit was set to 2.3x1020 years with a 90% confidence level. A perspective on the current experiment is discussed.

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

    International Nuclear Information System (INIS)

    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

  4. A novel radioguided surgery technique exploiting $\\beta^{-}$ decays

    CERN Document Server

    Camillocci, E Solfaroli; Bellini, F; Bocci, V; Collamati, F; Cremonesi, M; De Lucia, E; Ferroli, P; Fiore, S; Grana, C M; Marafini, M; Mattei, I; Morganti, S; Paganelli, G; Patera, V; Piersanti, L; Recchia, L; Russomando, A; Schiariti, M; Sarti, A; Sciubba, A; Voena, C; Faccini, R

    2014-01-01

    The background induced by the high penetration power of the gamma radiation is the main limiting factor of the current Radio-guided surgery (RGS). To partially mitigate it, a RGS with beta+ emitting radio-tracers has been suggested in literature. Here we propose the use of beta- emitting radio-tracers and beta- probes and discuss the advantage of this method with respect to the previously explored ones: the electron low penetration power allows for simple and versatile probes and could extend RGS to tumours for which background originating from nearby healthy tissue makes gamma probes less effective. We developed a beta- probe prototype and studied its performances on phantoms. By means of a detailed simulation we have also extrapolated the results to estimate the performances in a realistic case of meningioma, pathology which is going to be our first in-vivo test case. A good sensitivity to residuals down to 0.1ml can be reached within 1s with an administered activity smaller than those for PET-scans thus ma...

  5. ${\\beta}$-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.

  6. Recent status of the studies of nuclear masses and {beta}-decay

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, Masami [Waseda Univ., Tokyo (Japan). Advanced Research Center for Science and Engineering

    1996-05-01

    The recent status of the above studies was explained, especially, nuclear masses were described from the aspect of probability theory and that of {beta}-decay suggested that the first forbidden transition was hindered between the ground states. We have to study various systematics in order to know the mass surface, Way-Yamada-Matumoto type systematics is better to check the experimental nuclear masses. The gross theory is very useful to understand the general aspect of {beta}-decay. The understanding method of mass surface, systematic check of mass and hindrance of the first forbidden transition at rank 1 were explained. (S.Y.)

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

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

    2000-12-01

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

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

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

    CERN Document Server

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

    2014-01-01

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

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

    International Nuclear Information System (INIS)

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

  13. Effects of Beta-Decays of Excited-State Nuclei on the Astrophysical r-Process

    CERN Document Server

    Famiano, M A; Kajino, T; Otsuki, K; Terasawa, M; Mathews, G J

    2008-01-01

    A rudimentary calculation is employed to evaluate the possible effects of beta- decays of excited-state nuclei on the astrophysical r-process. Single-particle levels calculated with the FRDM are adapted to the calculation of beta-decay rates of these excited-state nuclei. Quantum numbers are determined based on proximity to Nilson model levels. The resulting rates are used in an r-process network calculation in which a supernova hot-bubble model is coupled to an extensive network calculation including all nuclei between the valley of stability and the neutron drip line and with masses A<284. Beta-decay rates are included as functional forms of the environmental temperature. While the decay rate model used is simple and phenomenological, it is consistent across all 3700 nuclei involved in the r-process network calculation. This represents an approximate first estimate to gauge the possible effects of excited-state beta-decays on r-process freeze-out abundances.

  14. 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+ ions in gaseous xenon. Through

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

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

    2006-12-01

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

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

    International Nuclear Information System (INIS)

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

  18. Recoil ion charge state distribution following the beta(sup +) decay of {sup 21}Na

    Energy Technology Data Exchange (ETDEWEB)

    Scielzo, Nicholas D.; Freedman, Stuart J.; Fujikawa, Brian K.; Vetter, Paul A.

    2003-01-03

    The charge state distribution following the positron decay of 21Na has been measured, with a larger than expected fraction of the daughter 21Ne in positive charge states. No dependence on either the positron or recoil nucleus energy is observed. The data is compared to a simple model based on the sudden approximation. Calculations suggest a small but important contribution from recoil ionization has important consequences for precision beta decay correlation experiments detecting recoil ions.

  19. Recoil ion charge state distribution following the beta(sup +) decay of 21Na

    International Nuclear Information System (INIS)

    The charge state distribution following the positron decay of 21Na has been measured, with a larger than expected fraction of the daughter 21Ne in positive charge states. No dependence on either the positron or recoil nucleus energy is observed. The data is compared to a simple model based on the sudden approximation. Calculations suggest a small but important contribution from recoil ionization has important consequences for precision beta decay correlation experiments detecting recoil ions

  20. The K-Forbidden Beta Decay of Tb160

    DEFF Research Database (Denmark)

    Hansen, P. Gregers; Johnson, N. R.; Nielsen, H. L.

    1964-01-01

    The β decay of the odd nucleus Tb160(Iπ = 3−) is shown to populate the 2+ and 4+ states of the ground-state band of Dy160 in intensities of 0.34% and 0.12%, respectively. The ratio of the reduced transition probabilities and the absolute transition strength are both compared with theoretical...

  1. Free-Neutron Beta-Decay Half-Life

    DEFF Research Database (Denmark)

    Christensen, Carl Jørgen; Nielsen, A.; Bahnsen, A.;

    1972-01-01

    The β-decay half-life of the free neutron was measured. Greater accuracy was obtained through the development of a special 4πβ spectrometer with a well-defined source volume and through the use of a new density calibration method with a 3He proportional counter. A clean thermal-neutron beam was...

  2. Effective ecological half-lives of Cs-137 for fishes controlled by their surrounding sea-waters

    International Nuclear Information System (INIS)

    National Research Institute of Fisheries Science (NRIFS) has carried out the long term monitoring program for radioactive pollution in marine organisms caught around Japan in order to confirm the safety of marine organisms as food source. Main radionuclide in our monitoring program is Cs-137 because it has the relatively high radiotoxicity and the long term physical half-life (about 30.1 y), and tends to accumulate in the muscle. Recently, the effective ecological half-lives have been introduced to estimate the recovery time from radioactive pollution, and been applicable to various ecosystems. In this study, effective ecological half-lives of Cs-137 for some fishes were calculated from our long term monitoring data. It is known that fish species have each effective ecological half-lives. However, it has been unclear what change the effective ecological half-lives of Cs-137 for fishes. Fishes intake Cs-137 through food chain and directly from their surrounding sea-waters. Accordingly, the effective ecological half-lives of Cs-137 for some fishes would be controlled by the effective environment half-lives of Cs-137 for their surrounding sea-waters. There is difference in effective environment half-lives of Cs-137 between the open ocean and the coastal sea-waters because they have the different input sources of Cs-137. Some fishes move between the open ocean and the coastal areas, and therefore their effective ecological half-lives of Cs-137 are influenced by the effective environment half-lives of Cs-137 for sea-waters of both areas. Consequently, the differences in effective ecological half-lives of Cs-137 among fish species would depend the rate of coastal area in their lives. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-12-15

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

  4. 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.

  5. New limits on double beta decay of 106Cd

    Science.gov (United States)

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

    2011-02-01

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

  6. Beta-alpha correlation in the decay of 20Na

    International Nuclear Information System (INIS)

    The β-α angular correlation has been measured in the allowed positron decay of 20Na to the 7.42 MeV state of 20Ne. The correlation is of the form 1+a(mean)cos(theta) + p(mean)cos2(theta). p(mean)=-0.003+-0.005 is found in reasonable agreement with expectations based on the conserved vector current theory. (Auth.)

  7. The isospin mixing and the superallowed Fermi beta decay

    Indian Academy of Sciences (India)

    A E Çalik; M Gerçekliğlu; D I Salamov

    2012-09-01

    In the present work, the isospin admixtures in the nuclear ground states of the parent nuclei and isospin structure of the isobar analog resonance (IAR) states have been investigated by studying the 0+ → 0+ superallowed Fermi decays using Pyatov’s restoration method. Within the random phase approximation (RPA), in this method, the effect of isospin breaking due to the Coulomb forces has been evaluated, taking into account the effect of pairing correlations between nucleons.

  8. Beta decay measurements with ultracold neutrons: a review of recent measurements and the research program at Los Alamos National Laboratory

    International Nuclear Information System (INIS)

    We present a review of the motivation and results of recent experiments which utilize ultracold neutrons for measurements of neutron beta decay. Because these experiments hinge critically on the available ultracold neutron source technology, we also review the status of ultracold neutron source development, emphasizing the Los Alamos ultracold neutron facility and the ongoing beta decay research program sited there. (paper)

  9. Stellar $\\beta^{\\pm}$ decay rates of iron isotopes and its implications in astrophysics

    CERN Document Server

    Nabi, Jameel-Un

    2014-01-01

    $\\beta$-decay and positron decay are believed to play a consequential role during the late phases of stellar evolution of a massive star culminating in a supernova explosion. Recently the microscopic calculation of weak-interaction mediated rates on key isotopes of iron was introduced using the proton-neutron quasiparticle random phase approximation (pn-QRPA) theory with improved model parameters. Here I discuss in detail the improved calculation of $\\beta^{\\pm}$ decay rates for iron isotopes ($^{54,55,56}$Fe) in stellar environment. The pn-QRPA theory allows a microscopic "state-by-state" calculation of stellar rates as explained later in text. Excited state Gamow-Teller distributions are much different from ground state and a microscopic calculation of decay rates from these excited states greatly increases the reliability of the total decay rate calculation specially during the late stages of stellar evolution. The reported decay rates are also compared with earlier calculations. The positron decay rates a...

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

    International Nuclear Information System (INIS)

    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

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

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

    CERN Document Server

    Pandola, Luciano

    2014-01-01

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

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

    CERN Document Server

    Borah, Debasish

    2015-01-01

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

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

    CERN Document Server

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

    2007-01-01

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

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

    International Nuclear Information System (INIS)

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

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

    CERN Document Server

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

    2016-01-01

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

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

    Science.gov (United States)

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

    2015-10-01

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

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

    CERN Document Server

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

    2009-01-01

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

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

    CERN Document Server

    London, D

    1999-01-01

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

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

    Science.gov (United States)

    Sinclair, D.; Exo Collaboration

    2010-01-01

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

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

    Science.gov (United States)

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

    2012-08-01

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

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

    Science.gov (United States)

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

    1998-02-01

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

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

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

    CERN Document Server

    Kota, V K B

    2016-01-01

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

  8. Statistical criteria for possible indications of new physics in tritium $\\beta$-decay spectrum

    CERN Document Server

    Lokhov, Aleksei

    2014-01-01

    The method of quasi-optimal weights is applied to constructing (quasi-)optimal criteria for various anomalous contributions in experimental spectra. Anomalies in the spectra could indicate physics beyond the Standard Model (additional interactions and neutrino flavours, Lorenz violation etc.). In particular the cumulative tritium $\\beta$-decay spectrum (for instance, in Troitsk-$\

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

    Science.gov (United States)

    Borah, Debasish; Dasgupta, Arnab

    2015-11-01

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

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

    CERN Document Server

    Barea, J; Iachello, F

    2015-01-01

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

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

  13. Uranium and plutonium total half-lives and for the spontaneous fission branch

    Energy Technology Data Exchange (ETDEWEB)

    Holden, N.E.

    1985-01-01

    The long-lived nuclides of the uranium and plutonium elements are of interest for their use in nuclear reactors, as well as in certain safeguard applications, e.g., alpha counting is often used to determine the amount of material present. The total half-life and the half-life for spontaneous fission are evaluated for these various long-lived nuclides of interest. The various experiments have been reanalyzed and recommended values are presented for /sup 232,233,234/U, /sup 235,236,238/U, and for /sup 236,238,239,240,241,242,244/Pu. These values improve upon preliminary estimates previously presented, in particular with respect to the uncertainties reported. The /sup 234/U half-life of 2.456 +- 0.005 x 10/sup 5/ years impacts directly on the 2200 meters/second fission cross section of /sup 235/U, since earlier measurements used values of 2.47 to 2.5 x 10/sup 5/ years and obtained correspondingly lower cross sections. In a similar manner, the /sup 239/Pu half-life is 1.25% lower than earlier estimates, which results in a 1.25% increase in the 2200 m/s fission cross section for /sup 239/Pu in some earlier cross section measurements. The total half-lives for the uranium nuclides were reviewed some time ago. At that time, the only spontaneous fission value which was evaluated was /sup 238/U. Recently, the uranium and plutonium nuclides were reviewed for both total and fission half-lives. The general procedure followed in this paper has been to review each of the experiments and revise the published values for the latest estimates of the various parameters used by the original authors. For the case of the total half-lives of uranium, only differences from the original work have been discussed. 120 refs., 23 tabs.

  14. Uranium and plutonium total half-lives and for the spontaneous fission branch

    International Nuclear Information System (INIS)

    The long-lived nuclides of the uranium and plutonium elements are of interest for their use in nuclear reactors, as well as in certain safeguard applications, e.g., alpha counting is often used to determine the amount of material present. The total half-life and the half-life for spontaneous fission are evaluated for these various long-lived nuclides of interest. The various experiments have been reanalyzed and recommended values are presented for /sup 232,233,234/U, /sup 235,236,238/U, and for /sup 236,238,239,240,241,242,244/Pu. These values improve upon preliminary estimates previously presented, in particular with respect to the uncertainties reported. The 234U half-life of 2.456 +- 0.005 x 105 years impacts directly on the 2200 meters/second fission cross section of 235U, since earlier measurements used values of 2.47 to 2.5 x 105 years and obtained correspondingly lower cross sections. In a similar manner, the 239Pu half-life is 1.25% lower than earlier estimates, which results in a 1.25% increase in the 2200 m/s fission cross section for 239Pu in some earlier cross section measurements. The total half-lives for the uranium nuclides were reviewed some time ago. At that time, the only spontaneous fission value which was evaluated was 238U. Recently, the uranium and plutonium nuclides were reviewed for both total and fission half-lives. The general procedure followed in this paper has been to review each of the experiments and revise the published values for the latest estimates of the various parameters used by the original authors. For the case of the total half-lives of uranium, only differences from the original work have been discussed. 120 refs., 23 tabs

  15. First observation of $\\beta$-delayed $\\gamma$-proton decay in the $T_z$ = -2, $^{56}$Zn nucleus

    CERN Document Server

    Orrigo, S E A; Fujita, Y; Blank, B; Gelletly, W; Agramunt, J; Algora, A; Ascher, P; Bilgier, B; Cáceres, L; Cakirli, R B; Fujita, H; Ganioğlu, E; Gerbaux, M; Giovinazzo, J; Grévy, S; Kamalou, O; Kozer, H C; Kucuk, L; Kurtukian-Nieto, T; Molina, F; Popescu, L; Rogers, A M; Susoy, G; Stodel, C; Suzuki, T; Tamii, A; Thomas, J C

    2014-01-01

    We report on the first experimental observation of a very exotic decay mode at the proton drip-line, the $\\beta$-delayed $\\gamma$-proton decay, clearly seen in the $\\beta$ decay of the $T_z$ = -2, $^{56}$Zn nucleus. The $^{56}$Zn half-life and decay scheme have been determined. The decay proceeds by $\\beta$-delayed proton emission and $\\beta$-delayed $\\gamma$ de-excitation. The exotic $\\beta$-delayed $\\gamma$-proton emission was also detected in three cases. It affects the usual determination of the Gamow-Teller (GT) strength. Absolute Fermi and GT strengths have been deduced. Evidence for fragmentation of the Fermi strength due to isospin mixing is found.

  16. Half-lives of radionuclides used in nuclear geochronology and cosmochronology (evaluated data)

    International Nuclear Information System (INIS)

    Evaluated half-life values are given for the radionuclides 26Al, 40K, 53Mn, 60Fe, 87Rb, 93Zr, 98Tc, 107Pd, 129I, 135Cs, 146Sm, 176Lu, 182Hf, 187Re, 205Pb, 232Th, 235U, 238U, 244Pu and 247Cm. These were obtained from an analysis of published information up to 2001. These half-lives are used in geochronology and cosmochronology to determine different radiometric ages in the history of the earth, solar system and galaxy. (author)

  17. Whole-body effective half-lives for radiolabeled antibodies and related issues

    Energy Technology Data Exchange (ETDEWEB)

    Kaurin, D.G.L.; Carsten, A.L.; Baum, J.W.; Barber, D.E.

    1996-08-01

    Radiolabeled antibodies (RABs) are being developed and used in medical imaging and therapy in rapidly increasing numbers. Data on the whole body half effective half-lives were calculated from external dose rates obtained from attending physicians and radiation safety officers at participating institutions. Calculations were made using exponential regression analysis of data from patients receiving single and multiple administrations. Theses data were analyzed on the basis of age, sex, isotope label, radiation energy, antibody type, disease treated, administration method, and number of administrations.

  18. Whole-body effective half-lives for radiolabeled antibodies and related issues

    International Nuclear Information System (INIS)

    Radiolabeled antibodies (RABs) are being developed and used in medical imaging and therapy in rapidly increasing numbers. Data on the whole body half effective half-lives were calculated from external dose rates obtained from attending physicians and radiation safety officers at participating institutions. Calculations were made using exponential regression analysis of data from patients receiving single and multiple administrations. Theses data were analyzed on the basis of age, sex, isotope label, radiation energy, antibody type, disease treated, administration method, and number of administrations

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

    International Nuclear Information System (INIS)

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

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

    CERN Document Server

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

    2015-01-01

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