International Nuclear Information System (INIS)
Boutin, D.
2005-08-01
The first experimental observation of bound-state beta-decay showed, that due solely to the electron stripping, a stable nuclide, e.g. 163 Dy, became unstable. Also a drastic modification of the half-life of bare 187 Re, from 4.12(2) x 10 10 years down to 32.9(20) years, could be observed. It was mainly due to the possibility for the mother nuclide to decay into a previously inaccessible nuclear level of the daughter nuclide. It was proposed to study a nuclide where this decay mode was competing with continuum-state beta-decay, in order to measure their respective branchings. The ratio β b /β c could also be evaluated for the first time. 207 Tl was chosen due to its high atomic number, and Q-value of about 1.4 MeV, small enough to enhance the β b probability and large enough to allow the use of time-resolved Schottky Mass Spectrometry (SMS) to study the evolution of mother and bound-state beta-decay daughter ions. The decay properties of the ground state and isomeric state of 207 Tl 81+ have been investigated at the GSI accelerator facility in two separate experiments. For the first time β-decay where the electron could go either to a bound state (atomic orbitals) and lead to 207 Pb 81+ as a daughter nuclide, or to a continuum state and lead to 207 Pb 82+ , has been observed. The respective branchings of these two processes could be measured as well. The deduced total nuclear half-life of 255(17) s for 207 Tl 81+ , was slightly modified with respect to the half-life of the neutral atom of 286(2) s. It was nevertheless in very good agreement with calculations based on the assumption that the beta-decay was following an allowed type of transition. The branching β b /β c =0.192(20), was also in very good agreement with the same calculations. The application of stochastic precooling allowed to observe in addition the 1348 keV short-lived isomeric state of 207 Tl. The half-life of this isomeric state was measured as 1.47(32) s, which shows a small deviation
Energy Technology Data Exchange (ETDEWEB)
Boutin, D.
2005-08-01
The first experimental observation of bound-state beta-decay showed, that due solely to the electron stripping, a stable nuclide, e.g. {sup 163}Dy, became unstable. Also a drastic modification of the half-life of bare {sup 187}Re, from 4.12(2) x 10{sup 10} years down to 32.9(20) years, could be observed. It was mainly due to the possibility for the mother nuclide to decay into a previously inaccessible nuclear level of the daughter nuclide. It was proposed to study a nuclide where this decay mode was competing with continuum-state beta-decay, in order to measure their respective branchings. The ratio {beta}{sub b}/{beta}{sub c} could also be evaluated for the first time. {sup 207}Tl was chosen due to its high atomic number, and Q-value of about 1.4 MeV, small enough to enhance the {beta}{sub b} probability and large enough to allow the use of time-resolved Schottky Mass Spectrometry (SMS) to study the evolution of mother and bound-state beta-decay daughter ions. The decay properties of the ground state and isomeric state of {sup 207}Tl{sup 81+} have been investigated at the GSI accelerator facility in two separate experiments. For the first time {beta}-decay where the electron could go either to a bound state (atomic orbitals) and lead to {sup 207}Pb{sup 81+} as a daughter nuclide, or to a continuum state and lead to {sup 207}Pb{sup 82+}, has been observed. The respective branchings of these two processes could be measured as well. The deduced total nuclear half-life of 255(17) s for {sup 207}Tl{sup 81+}, was slightly modified with respect to the half-life of the neutral atom of 286(2) s. It was nevertheless in very good agreement with calculations based on the assumption that the beta-decay was following an allowed type of transition. The branching {beta}{sub b}/{beta}{sub c}=0.192(20), was also in very good agreement with the same calculations. The application of stochastic precooling allowed to observe in addition the 1348 keV short-lived isomeric state of {sup
Beta decay rates of nuclei with 65
Indian Academy of Sciences (India)
of spectral averaging theory for two-body nuclear Hamiltonian in a large nuclear shell ... Beta decay rates; supernova evolution; spectral distribution method. ... level density formula, Wigner's treatment of spectral fluctuations using matrix en-.
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.)
Beta decay rates of neutron-rich nuclei
Marketin, Tomislav; Huther, Lutz; Petković, Jelena; Paar, Nils; Martínez-Pinedo, Gabriel
2016-06-01
Heavy element nucleosynthesis models involve various properties of thousands of nuclei in order to simulate the intricate details of the process. By necessity, as most of these nuclei cannot be studied in a controlled environment, these models must rely on the nuclear structure models for input. Of all the properties, the beta-decay half-lives are one of the most important ones due to their direct impact on the resulting abundance distributions. In this study we present the results of a large-scale calculation based on the relativistic nuclear energy density functional, where both the allowed and the first-forbidden transitions are studied in more than 5000 neutron-rich nuclei. Aside from the astrophysical applications, the results of this calculation can also be employed in the modeling of the electron and antineutrino spectra from nuclear reactors.
Beta decay rates of neutron-rich nuclei
International Nuclear Information System (INIS)
Marketin, Tomislav; Petković, Jelena; Paar, Nils; Huther, Lutz; Martínez-Pinedo, Gabriel
2016-01-01
Heavy element nucleosynthesis models involve various properties of thousands of nuclei in order to simulate the intricate details of the process. By necessity, as most of these nuclei cannot be studied in a controlled environment, these models must rely on the nuclear structure models for input. Of all the properties, the beta-decay half-lives are one of the most important ones due to their direct impact on the resulting abundance distributions. In this study we present the results of a large-scale calculation based on the relativistic nuclear energy density functional, where both the allowed and the first-forbidden transitions are studied in more than 5000 neutron-rich nuclei. Aside from the astrophysical applications, the results of this calculation can also be employed in the modeling of the electron and antineutrino spectra from nuclear reactors.
Beta decay rates of neutron-rich nuclei
Energy Technology Data Exchange (ETDEWEB)
Marketin, Tomislav, E-mail: marketin@phy.hr; Petković, Jelena; Paar, Nils [Department of Physics, Faculty of Science, University of Zagreb, 10000 Zagreb (Croatia); Huther, Lutz [Institut für Kernphysik (Theoriezentrum), Technische Universität Darmstadt, 64289 Darmstadt (Germany); Martínez-Pinedo, Gabriel [Institut für Kernphysik (Theoriezentrum), Technische Universität Darmstadt, 64289 Darmstadt (Germany); GSI Helmholtzzentrum für Schwerioneneforschung, Planckstraße 1, 64291 Darmstadt (Germany)
2016-06-21
Heavy element nucleosynthesis models involve various properties of thousands of nuclei in order to simulate the intricate details of the process. By necessity, as most of these nuclei cannot be studied in a controlled environment, these models must rely on the nuclear structure models for input. Of all the properties, the beta-decay half-lives are one of the most important ones due to their direct impact on the resulting abundance distributions. In this study we present the results of a large-scale calculation based on the relativistic nuclear energy density functional, where both the allowed and the first-forbidden transitions are studied in more than 5000 neutron-rich nuclei. Aside from the astrophysical applications, the results of this calculation can also be employed in the modeling of the electron and antineutrino spectra from nuclear reactors.
Beta decay rates of neutron-rich nuclei
International Nuclear Information System (INIS)
Marketin, Tomislav; Huther, Lutz; Martínez-Pinedo, Gabriel
2015-01-01
Heavy element nucleosynthesis models involve various properties of thousands of nuclei in order to simulate the intricate details of the process. By necessity, as most of these nuclei cannot be studied in a controlled environment, these models must rely on the nuclear structure models for input. Of all the properties, the beta-decay half-lives are one of the most important ones due to their direct impact on the resulting abundance distributions. Currently, a single large-scale calculation is available based on a QRPA calculation with a schematic interaction on top of the Finite Range Droplet Model. In this study we present the results of a large-scale calculation based on the relativistic nuclear energy density functional, where both the allowed and the first-forbidden transitions are studied in more than 5000 neutron-rich nuclei
Beta decay rates of neutron-rich nuclei
Energy Technology Data Exchange (ETDEWEB)
Marketin, Tomislav, E-mail: marketin@phy.hr [Department of Physics, Faculty of Science, University of Zagreb, 10000 Zagreb (Croatia); Huther, Lutz [Institut für Kernphysik (Theoriezentrum), Technische Universität Darmstadt, 64289 Darmstadt (Germany); Martínez-Pinedo, Gabriel [Institut für Kernphysik (Theoriezentrum), Technische Universität Darmstadt, 64289 Darmstadt (Germany); GSI Helmholtzzentrum für Schwerioneneforschung, Planckstraße 1, 64291 Darmstadt (Germany)
2015-10-15
Heavy element nucleosynthesis models involve various properties of thousands of nuclei in order to simulate the intricate details of the process. By necessity, as most of these nuclei cannot be studied in a controlled environment, these models must rely on the nuclear structure models for input. Of all the properties, the beta-decay half-lives are one of the most important ones due to their direct impact on the resulting abundance distributions. Currently, a single large-scale calculation is available based on a QRPA calculation with a schematic interaction on top of the Finite Range Droplet Model. In this study we present the results of a large-scale calculation based on the relativistic nuclear energy density functional, where both the allowed and the first-forbidden transitions are studied in more than 5000 neutron-rich nuclei.
Beta-decay rate and beta-delayed neutron emission probability of improved gross theory
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
Beta decay and muon capture rates in a self-consistent relativistic framework
Energy Technology Data Exchange (ETDEWEB)
Marketin, Tomislav; Paar, Nils; Niksic, Tamara; Vretenar, Dario [Physics Department, Faculty of Science, University of Zagreb (Croatia); Ring, Peter [Physik-Department, Technische Universitaet Muenchen, D-85748 Muenchen (Germany)
2009-07-01
A fully consistent calculation of muon capture and beta decay rates is presented, based on a microscopic theoretical framework describing the semileptonic weak interaction processes. Nuclear ground state is determined using the Relativistic Hartree-Bogolyubov (RHB) model with density dependent meson-nucleon coupling constants, and transition rates are calculated via proton-neutron relativistic quasiparticle RPA using the same interaction as in the RHB equations. Muon capture rates are calculated for a wide range of nuclei along the valley of stability, from {sup 12}C to {sup 244}Pu, with accuracy of approximately 30%, using the interaction DD-ME2. Previous studies of beta decay rates have only taken into account Gamow-Teller transitions. We extend this approach by including forbidden transitions and systematically study their contribution to decay rates of exotic nuclei along the r-process path, which are important for constraining the conditions in which nucleosynthesis takes place.
Minimally allowed neutrinoless double beta decay rates within an anarchical framework
International Nuclear Information System (INIS)
Jenkins, James
2009-01-01
Neutrinoless double beta decay (ββ0ν) is the only realistic probe of the Majorana nature of the neutrino. In the standard picture, its rate is proportional to m ee , the e-e element of the Majorana neutrino mass matrix in the flavor basis. I explore minimally allowed m ee values within the framework of mass matrix anarchy where neutrino parameters are defined statistically at low energies. Distributions of mixing angles are well defined by the Haar integration measure, but masses are dependent on arbitrary weighting functions and boundary conditions. I survey the integration measure parameter space and find that for sufficiently convergent weightings, m ee is constrained between (0.01-0.4) eV at 90% confidence. Constraints from neutrino mixing data lower these bounds. Singular integration measures allow for arbitrarily small m ee values with the remaining elements ill-defined, but this condition constrains the flavor structure of the model's ultraviolet completion. ββ0ν bounds below m ee ∼5x10 -3 eV should indicate symmetry in the lepton sector, new light degrees of freedom, or the Dirac nature of the neutrino.
{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.)
Richman, Debra; Spyrou, Artemis; Dombos, Alex; Couture, Aaron; e15034 Collaboration
2017-09-01
Interest in 60Fe, a long lived radioisotope synthesized in massive stars, has recently peaked. The signature of its decay allows us to probe astrophysical processes, events such as the early formation of the solar system and nucleosynthesis. To understand these observations a complete understanding of the creation, destruction and nuclear properties of 60Fe in the astrophysical environment are required. Using the beta decay of 60Mn in conjunction with total absorption spectroscopy (TAS), made possible by the high efficiency gamma ray calorimeter SuN (Summing NaI detector) at the National Superconducting Cyclotron Laboratory (NSCL), to study the distribution of beta-decay intensity over the daughter-nucleus 60Fe, provides information about the structure of the daughter and improves the predictive power of astrophysical models. In addition to the ongoing TAS analysis, The Beta-Oslo method will be used to extract the nuclear level density and gamma-strength function of 60Fe providing much needed constraints on the neutron capture reaction rate responsible for the creation of this nucleus.
A measurement of the 2 neutrino double beta decay rate of Te-130 in the CUORICINO experiment
Energy Technology Data Exchange (ETDEWEB)
Kogler, Laura K. [Univ. of California, Berkeley, CA (United States)
2011-11-30
CUORICINO was a cryogenic bolometer experiment designed to search for neutrinoless double beta decay and other rare processes, including double beta decay with two neutrinos (2vββ). The experiment was located at Laboratori Nazionali del Gran Sasso and ran for a period of about 5 years, from 2003 to 2008. The detector consisted of an array of 62 TeO_{2} crystals arranged in a tower and operated at a temperature of 10 mK. Events depositing energy in the detectors, such as radioactive decays or impinging particles, produced thermal pulses in the crystals which were read out using sensitive thermistors. The experiment included 4 enriched crystals, 2 enriched with ^{130}Te and 2 with ^{128}Te, in order to aid in the measurement of the 2vββ rate. The enriched crystals contained a total of 350 g ^{130}Te. The 128-enriched (130-depleted) crystals were used as background monitors, so that the shared backgrounds could be subtracted from the energy spectrum of the 130- enriched crystals. Residual backgrounds in the subtracted spectrum were fit using spectra generated by Monte-Carlo simulations of natural radioactive contaminants located in and on the crystals. The 2vββ half-life was measured to be T^{2v}_{1/2} = [9.81± 0.96(stat)± 0.49(syst)] x10^{20} y.
Neutrinoless double beta decay
Indian Academy of Sciences (India)
2012-10-06
Oct 6, 2012 ... Anyhow, the 'multi-isotope' ansatz is needed to compensate for matrix element ... The neccessary half-life requirement to touch this ... site energy depositions (like double beta decay) and multiple site interactions (most of.
Double beta decay: experiments
International Nuclear Information System (INIS)
Fiorini, Ettore
2006-01-01
The results obtained so far and those of the running experiments on neutrinoless double beta decay are reviewed. The plans for second generation experiments, the techniques to be adopted and the expected sensitivities are compared and discussed
International Nuclear Information System (INIS)
Newman, D.E.
1975-01-01
Describes an experiment to measure beta decays of the sigma particle. Sigmas produced by stopping a K - beam in a liquid hydrogen target decayed in the following reactions: Kp → Σπ; Σ → Neν. The electron and pion were detected by wire spark chambers in a magnetic spectrometer and by plastic scintillators, and were differentiated by a threshold gas Cherenkov counter. The neutron was detected by liquid scintillation counters. The data (n = 3) shell electrons or the highly excited electrons decay first. Instead, it is suggested that when there are two to five electrons in highly excited states immediately after a heavy ion--atom collision the first transitions to occur will be among highly excited Rydberg states in a cascade down to the 4s, 4p, and 3d-subshells. If one of the long lived states becomes occupied by electrons promoted during the collision or by electrons falling from higher levels, it will not decay until after the valence shell decays. LMM rates calculated to test the methods used are compared to previous works. The mixing coefficients are given in terms of the states 4s4p, 45sp+-, and 5s5p. The applicability of Cooper, Fano, and Prats' discussion of the energies and transition rates of doubly excited states is considered
International Nuclear Information System (INIS)
Reiss, H.R.
1986-01-01
Certain nuclear beta decay transitions normally inhibited by angular momentum or parity considerations can be induced to occur by the application of an electromagnetic field. Such decays can be useful in the controlled production of power, and in fission waste disposal
International Nuclear Information System (INIS)
Piepke, A.
2005-01-01
The experimental observation of neutrino oscillations and thus neutrino mass and mixing gives a first hint at new particle physics. The absolute values of the neutrino mass and the properties of neutrinos under CP-conjugation remain unknown. The experimental investigation of the nuclear double beta decay is one of the key techniques for solving these open problems
Beta decay of highly charged ions
International Nuclear Information System (INIS)
Litvinov, Yuri A; Bosch, Fritz
2011-01-01
Beta decay of highly charged ions has attracted much attention in recent years. An obvious motivation for this research is that stellar nucleosynthesis proceeds at high temperatures where the involved atoms are highly ionized. Another important reason is addressing decays of well-defined quantum-mechanical systems, such as one-electron ions where all interactions with other electrons are excluded. The largest modifications of nuclear half-lives with respect to neutral atoms have been observed in beta decay of highly charged ions. These studies can be performed solely at ion storage rings and ion traps, because there high atomic charge states can be preserved for extended periods of time (up to several hours). Currently, all experimental results available in this field originate from experiments at the heavy-ion complex GSI in Darmstadt. There, the fragment separator facility FRS allows the production and separation of exotic, highly charged nuclides, which can then be stored and investigated in the storage ring facility ESR. In this review, we present and discuss in particular two-body beta decays, namely bound-state beta decay and orbital electron capture. Although we focus on experiments conducted at GSI, we will also attempt to provide general requirements common to any other experiment in this context. Finally, we address challenging but not yet performed experiments and we give prospects for the new radioactive beam facilities, such as FAIR in Darmstadt, IMP in Lanzhou and RIKEN in Wako.
International Nuclear Information System (INIS)
Badibanga, P.
1975-01-01
The Fermi functions F(E,Z) have been obtained in this paper for allowed transitions in the case of negatron emission. The potential used in solving the coupled pair of Dirac equations has been derived from the so-called Fermi-type charge-density distribution, where the parameters rho 0 , c and a are those from high-energy electron scattering experiments of Hofstadter et al. The following nuclei were investigated: 20 40 C, 23 51 V, 27 59 Co, 49 115 In, 51 122 Sb, 79 197 Au and 83 209 Bi. The kinetic energy of the emitted electrons was varied from 10 KeV to 10 MeV at intervals of 10 keV. Tables of the Fermi functions F(E,Z) for these nuclei are given in this paper. Also the corrections to the shape of the beta-decay energy spectra eta/sub F-H/(E,Z) were evaluated for the same values of the kinetic energy of the emitted electrons for the nuclei under investigation. Tables of these corrections are presented in this paper. It appears from the results obtained that both F(E,Z) and eta/sub F-H/(E,Z) are uniform functions of energy E; as for the variable Z, the curves obtained are not smooth, but have several kinks or breaks in them. We have found a large peak occurring at Z = 27 (Co), and for eta/sub F-H/(E,Z) In has larger values than Sb
International Nuclear Information System (INIS)
Fiorini, Ettore
2008-01-01
The importance of neutrinoless Double Beta Decay (DBD) is stressed in view of the recent results of experiments on neutrino oscillations which indicate that the difference between the squared masses of two neutrinos of different flavours is finite [For a recent review including neutrino properties and recent results see: Review of Particle Physics, J. of Phys. G: Nuclear and Particle Physics 33, 1]. As a consequence the mass of at least one neutrino has to be different from zero and it becomes imperative to determine its absolute value. The various experimental techniques to search for DBD are discussed together with the difficult problems of the evaluation of the corresponding nuclear matrix elements. The upper limits on neutrino mass coming from the results of the various experiments are reported together with the indication for a non zero value by one of them not confirmed so far. The two presently running experiments on neutrinoless DBD are briefly described together with the already approved or designed second generation searches aiming to reach the values on the absolute neutrino mass indicated by the results on neutrino oscillations
Nuclear structure and double beta decay
International Nuclear Information System (INIS)
Vogel, P.
1988-01-01
Double beta decay is a rare transition between two nuclei of the same mass number A involving a change of the nuclear charge Z by two units. It has long been recognized that the Oν mode of double beta decay, where two electrons and no neutrinos are emitted, is a powerful tool for the study of neutrino properties. Its observation would constitute a convincing proof that there exists a massive Majorana neutrino which couples to electrons. Double beta decay is a process involving an intricate mixture of particle physics and physics of the nucleus. The principal nuclear physics issues have to do with the evaluation of the nuclear matrix elements responsible for the decay. If the authors wish to arrive at quantitative answers for the neutrino properties the authors have no choice but to learn first how to understand the nuclear mechanisms. The authors describe first the calculation of the decay rate of the 2ν mode of double beta decay, in which two electrons and two antineutrinos are emitted
Borcea, R; Aysto, J; Caurier, E; Dendooven, P; Doring, J; Gierlik, M; Gorska, M; Grawe, H; Hellstrom, M; Janas, Z; Jokinen, A; Karny, M; Kirchner, R; La Commara, M; Langanke, K; Martinez-Pinedo, G; Mayet, P; Nieminen, A; Nowacki, F; Penttila, H; Plochocki, A; Rejmund, M; Roeckl, E; Schlegel, C; Schmidt, K; Schwengner, R; Sawicka, M
2001-01-01
The proton-rich isotope Cu-56 was produced at the GSI On-Line Mass Separator by means of the Si-28(S-32, p3n) fusion-evaporation reaction. Its beta -decay properties were studied by detecting beta -delayed gamma rays and protons. A half-Life of 93 +/- 3 ms was determined for Cu-56. Compared to the
Constraining neutrinoless double beta decay
International Nuclear Information System (INIS)
Dorame, L.; Meloni, D.; Morisi, S.; Peinado, E.; Valle, J.W.F.
2012-01-01
A class of discrete flavor-symmetry-based models predicts constrained neutrino mass matrix schemes that lead to specific neutrino mass sum-rules (MSR). We show how these theories may constrain the absolute scale of neutrino mass, leading in most of the cases to a lower bound on the neutrinoless double beta decay effective amplitude.
International Nuclear Information System (INIS)
Hubert, F.; Dufour, J.P.; Moral, R. del; Fleury, A.; Jean, D.; Pravikoff, M.S.; Delagrange, H.; Geissel, H.; Schmidt, K.H.; Hanelt, E.
1989-01-01
The beta-gamma spectroscopic study of 22 O is presented. This nucleus, produced as a projectile-like fragment from the interaction of a 60 MeV/n 40 Ar beam with a Be target, has been separated by the LISE spectrometer. Several gamma rays from 22 O decay have been observed, from which a half-life of (2.25±0.15) s has been determined. Accurate excitation energies have been deduced for several states in 22 F. A partial beta decay scheme of 22 O has been established. Experimental results have been compared with shell model calculations. (orig.)
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.
Neutrinoless Double Beta Decay Experiments
International Nuclear Information System (INIS)
Garfagnini, A.
2014-08-01
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 per- formed in the past, a new generation of experiments using different isotopes and techniques have recently released their results or are taking data and will provide new limits, should no signal be observed, in the next few years to come. The present contribution reviews the latest public results on double beta decay searches and gives an overview on the expected sensitivities of the experiments in construction which will be able to set stronger limits in the near future. EXO and KamLAND-Zen experiments are based on the decay of Xe 136 , GERDA and MAJORANA experiments are based on the decay of Ge 76 , and the CUORE experiment is based on the decay of Te 130
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.
Theoretical aspects of double beta decay
International Nuclear Information System (INIS)
Haxton, W.C.
1984-01-01
Considerable effort has been expended recently in theoretical studies of double beta decay. Much of this work has focussed on the constraints this process places on gauge theories of the weak interaction, in general, and on the neutrino mass matrix, in particular. In addition, interesting nuclear structure questions have arisen in studies of double beta decay matrix elements. After briefly reviewing the theory of double beta decay, some of the progress that has been made in these areas is summarized. 25 references
Sensitivity of NEXT-100 to neutrinoless double beta decay
Martín-Albo, J.; Ferrario, P.; Nebot-Guinot, M.; Gómez-Cadenas, J.J.; Álvarez, V.; Azevedo, C.D.R.; Borges, F.I.G.; Cárcel, S.; Cebrián, S.; Cervera, A.; Conde, C.A.N.; Díaz, J.; Diesburg, M.; Esteve, R.; Fernandes, L.M.P.; Ferreira, A.L.; Freitas, E.D.C.; Gehman, V.M.; Goldschmidt, A.; González-Díaz, D.; Gutiérrez, R.M.; Henriques, C.A.O.; Hernando Morata, J.A.; Labarga, L.; Laing, A.; Lebrun, P.; Liubarsky, I.; López-March, N.; Lorca, D.; Losada, M.; Martínez-Lema, G.; Martínez, A.; Miller, T.; Monrabal, F.; Monserrate, M.; Monteiro, C.M.B.; Mora, F.J.; Moutinho, L.M.; Novella, P.; Nygren, D.; Para, A.; Perez, J.; Perez Aparicio, J.L.; Querol, M.; Renner, J.; Ripoll, L.; Rodríguez, J.; Santos, F.P.; dos Santos, J.M.F.; Serra, L.; Shuman, D.; Simón, A.; Sofka, C.; Sorel, M.; Stiegler, T.; Toledo, J.F.; Torrent, J.; Tsamalaidze, Z.; Veloso, J.F.C.A.; Villar, J.A.; Webb, R.; White, J.T.; Yahlali, N.; Yepes-Ramírez, H.; Hauptman, J.
2016-01-01
NEXT-100 is an electroluminescent high-pressure xenon gas time projection chamber that will search for the neutrinoless double beta decay of Xe-136. The detector possesses two features of great value in neutrinoless double beta decay searches: very good energy resolution (better than 1% FWHM at the Q value of Xe-136) and track reconstruction for the discrimination of signal and background events. This combination results in excellent sensitivity, as discussed in this paper. Detailed Monte Carlo detector simulations and material-screening measurements predict a background rate for NEXT-100 of at most 0.0004 counts/(keV kg yr). Accordingly, the detector will reach a sensitivity to the neutrinoless double beta decay half-life of 6.E25 years after running for 3 effective years.
Weissman, L; Bergmann, U C; Brown, B A; Catherall, R; Cederkäll, J; Dillmann, I; Hallmann, O; Fraile-Prieto, L M; Franchoo, S; Gaudefroy, L; Köster, U; Kratz, K L; Pfeiffer, B; Sorlin, O; 10.1103/PhysRevC.70.024304
2004-01-01
Information on beta -decay properties of neutron-rich /sup 47/Ar was obtained at the ISOLDE facility at CERN using isobaric selectivity. This was achieved by a combination of a plasma-ion source with a cooled transfer line and subsequent mass separation. A doubly charged beam was used in order to improve the signal-to-background ratio associated with multi-charged noble gas fission products. The identification of the /sup 47/Ar gamma -ray transitions was performed by comparing the spectra obtained from direct proton bombardment of the target and of the neutron converter. New excited levels in the daughter /sup 47/K nucleus corresponding to the negative-parity states were observed. The obtained data are compared to the result of large-scale shell model calculations and quasiparticle random-phase approximation predictions. (29 refs).
Double beta decay and neutrino mass models
Energy Technology Data Exchange (ETDEWEB)
Helo, J.C. [Universidad Técnica Federico Santa María, Centro-Científico-Tecnológico de Valparaíso, Casilla 110-V, Valparaíso (Chile); Hirsch, M. [AHEP Group, Instituto de Física Corpuscular - C.S.I.C./Universitat de València, Edificio de Institutos de Paterna, Apartado 22085, E-46071 València (Spain); Ota, T. [Department of Physics, Saitama University, Shimo-Okubo 255, 338-8570 Saitama-Sakura (Japan); Santos, F.A. Pereira dos [Departamento de Física, Pontifícia Universidade Católica do Rio de Janeiro,Rua Marquês de São Vicente 225, 22451-900 Gávea, Rio de Janeiro (Brazil)
2015-05-19
Neutrinoless double beta decay allows to constrain lepton number violating extensions of the standard model. If neutrinos are Majorana particles, the mass mechanism will always contribute to the decay rate, however, it is not a priori guaranteed to be the dominant contribution in all models. Here, we discuss whether the mass mechanism dominates or not from the theory point of view. We classify all possible (scalar-mediated) short-range contributions to the decay rate according to the loop level, at which the corresponding models will generate Majorana neutrino masses, and discuss the expected relative size of the different contributions to the decay rate in each class. Our discussion is general for models based on the SM group but does not cover models with an extended gauge. We also work out the phenomenology of one concrete 2-loop model in which both, mass mechanism and short-range diagram, might lead to competitive contributions, in some detail.
New developments in the calculation of double beta decay
International Nuclear Information System (INIS)
Engel, J.
1990-01-01
I review recent work on computing double beta decay rates. After a discussion of shell model and Quasiparticle Random Phase calculations, I argue for a model based on the notion of generalized seniority that combines the advantages of both earlier approaches. (orig.)
Review of modern double beta decay experiments
Barabash, A. S.
2015-10-01
The review of modern experiments on search and studying of double beta decay processes is done. Results of the most sensitive current experiments are discussed. The main attention is paid to EXO-200, KamLAND-Zen, GERDA-I and CUORE-0 experiments. Modern values of T1/2(2ν) and best present limits on neutrinoless double beta decay and double beta decay with Majoron emission are presented. Conservative limits on effective mass of a Majorana neutrino ( at the level of ˜ 0.01-0.1 eV are discussed.
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.
Nuclear beta decay and the weak interaction
International Nuclear Information System (INIS)
Kean, D.C.
1975-11-01
Short notes are presented on various aspects of nuclear beta decay and weak interactions including: super-allowed transitions, parity violation, interaction strengths, coupling constants, and the current-current formalism of weak interaction. (R.L.)
International Nuclear Information System (INIS)
Elliott, S.R.; Hahn, A.A.; Moe, M.K.; Nelson, M.A.; Vient, M.A.
1992-01-01
The two-neutrino double beta decay of 82 Se has been measured during a 20 244 h run resulting in a half-life of 1.08 -0.06 +0.26 x10 20 years (68% C.L.). No candidate events for the zero-neutrino double beta decay during 21 924 h results in a half-life limit of 2.7x10 22 years at the 68% confidence level
International Nuclear Information System (INIS)
Inoue, J.; Ohtaka, K.
2004-01-01
We study virtual bound states in photonics, which are a vectorial extension of electron virtual bound states. The condition for these states is derived. It is found that the Mie resonant state which satisfies the condition that the size parameter is less than the angular momentum should be interpreted as a photon virtual bound state. In order to confirm the validity of the concept, we compare the photonic density of states, the width of which represents the lifetime of the photon virtual bound states, with numerical results
Beta decay and rhenium cosmochronology
International Nuclear Information System (INIS)
Ashktorab, K.
1992-01-01
Among the problems which limit the use of the 187 Re/ 187 Os isobaric pair as a cosmochronometer for the age of the galaxy and the universe are the uncertainties in the partial half-lives of the continuum and bound state decays of 187 Re. While the total half-life of the decay is well established, the partial half-life for the continuum decay is uncertain, and several measurements are not compatible. A high temperature quartz proportional counter was used in this work to remeasure the continuum β - decay of 187 Re. The β endpoint energy for the decay of neutral 187 Re to singly ionized 187 Os of 2.75 ± 0.06 keV agrees with the earlier results. The corresponding half-life of (45 ± 3) x 10 9 years improves and agrees with the earlier measurement of Payne and Drever and refutes other measurements. Based on the new half-life for the continuum decay and a total half-life of (43.5 ± 1.3) x 10 9 years reported by Linder et al., the branching ratio for the bound state decay into discrete atomic states is estimated to be (3 ± 6)% in agreement with the most recent calculated theoretical branching ratio of approximately 1%. Anomalies in beta spectra reported by J.J. Simpson and others have been attributed to a 17 keV heavy-neutrino admixture. If confirmed, the implications from the existence of such a neutrino for particle and astrophysics would be significant. A multiwire open-quotes wall-lessclose quotes stainless steel proportional counter has been used in the present work to investigate the spectral shape of the β decay of 63 Ni. No anomalies in the spectral shape were observed which could be attributed to the presence of 17 keV heavy neutrino
Is neutrinoless double beta decay suppressed
International Nuclear Information System (INIS)
Tomoda, T.
1989-01-01
Much effort has been devoted to the study of nuclear double beta decay, since the observation of a neutrinoless double beta (OνΒΒ) decay would be clear evidence that the electron neutrino is a Majorana particle. The OνΒΒ decay is caused by a finite Majorana neutrino mass and/or an admixture of right-handed leptonic currents. In order to relate these quantities to OνΒΒ decay rates, we need nuclear matrix elements, which are model dependent. One of the possibilities of testing nuclear models employed in such analysis is to calculate the experimentally known rates of ΒΒ decay with emission of two neutrinos (2νΒΒ decay) which occurs independently of the nature of the neutrino. There was a long-standing difficulty in such attempts that the calculated 2νΒΒ decay rates turned out to be always too large by one to two orders of magnitude. Trying to overcome such difficulty, Klapdor and Grotz as well as Vogel and Zirnbauer showed in their calculation using schematic effective interactions such that 2νΒΒ decay rates can get reduced considerably due to the nuclear ground state correlations. This paper reports that the suppression is ascribed to that of the virtual Gamow-Teller transitions from the excited 1 + states of the intermediate odd-odd -even nucleus
Why search for double beta decay?
International Nuclear Information System (INIS)
Kayser, B.
1988-01-01
Searching for neutrinoless double beta decay is the only known practical method for trying to determine whether neutrinos are their own antiparticles. The theoretical motivation for supposing that they may indeed be their own antiparticles is described. The reason that it is so difficult to ascertain experimentally whether they are or are not is explained, as is the special sensitivity of neutrinoless double beta decay. The potential implications of the observation of this reaction for neutrino mass and for the physics of neutrinos is discussed
Majorana neutrinos and double beta-decay
International Nuclear Information System (INIS)
Shchepkin, M.G.
1986-01-01
Problem, related to neutrino mass and lepton charge L conservation is briefly discussed. A possibility to experimentally test L conservation in different processes and to produce limitations for neutrino mass in double beta-decay processes is considered. Planned experiments on studying the double neutrinoless (2β) beta-decays and searching 2β(2ν)-decays, permitted by the conservation laws, are discussed. It is stressed, that comparison of the existing theoretical predictions of 2β(2ν)-decay probability with experimental results will make it possible to choose the most adequate approach to the calculation of double β-transition nuclear amplitudes
Search for Neutrinoless Double-Beta Decay
Tornow, Werner
2014-01-01
After the pioneering work of the Heidelberg-Moscow (HDM) and International Germanium Experiment (IGEX) groups, the second round of neutrinoless double-$\\beta$ decay searches currently underway has or will improve the life-time limits of double-$\\beta$ decay candidates by a factor of two to three, reaching in the near future the $T_{1/2} = 3 \\times 10^{25}$ yr level. This talk will focus on the large-scale experiments GERDA, EXO-200, and KamLAND-Zen, which have reported already lower half-life...
Precision measurements in nuclear beta decay
Energy Technology Data Exchange (ETDEWEB)
Naviliat-Cuncic, Oscar, E-mail: naviliat@nscl.msu.edu [Michigan State University, National Superconducting Cyclotron Laboratory and Department of Physics and Astronomy (United States)
2013-03-15
Precision measurements in nuclear beta decay provide sensitive means to determine the fundamental coupling of charged fermions to weak bosons and to test discrete symmetries in the weak interaction. The main motivation of such measurements is to find deviations from Standard Model predictions as possible indications of new physics. I focus here on two topics related to precision measurements in beta decay, namely: (i) the determination of the V{sub ud} element of the Cabibbo-Kobayashi-Maskawa quark mixing matrix from nuclear mirror transitions and (ii) selected measurements of time reversal violating correlations in nuclear and neutron decays. These topics complement those presented in other contributions to this conference.
Measuring pion beta decay with high-energy pion beams
International Nuclear Information System (INIS)
McFarlane, W.K.; Hoffman, C.M.
1993-01-01
Improved measurements of the pion beta decay rate are possible with an intense high-energy pion beam. The rate for the decay π + → π 0 e + vε is predicted by the Standard Model (SM) to be R(π + → π 0 e + vε) = 0.3999±0.0005 s -1 . The best experimental number, obtained using in-flight decays, is R(π + → π 0 e + vε) = 0.394 ± 0.015 s -1 . A precise measurement would test the SM by testing the unitarity of the Cabibbo-Kobayashi-Maskawa matrix for which one analysis of the nuclear beta decay data has shown a 0.4% discrepancy. Several nuclear correction factors, needed for nuclear decay, are not present for pion beta decay, so that an experiment at the 0.2% level would be a significant one. Detailed study of possible designs will be needed, as well as extensive testing of components. The reduction of systematic errors to the 0.1% level can only be done over a period of years with a highly stable apparatus and beam. At a minimum, three years of occupancy of a beam line, with 800 hours per year, would be required
Double-beta decay processes from lattice quantum chromodynamics
Davoudi, Zohreh; Tiburzi, Brian; Wagman, Michael; Winter, Frank; Chang, Emmanuel; Detmold, William; Orginos, Kostas; Savage, Martin; Shanahan, Phiala; Nplqcd Collaboration
2017-09-01
While an observation of neutrinoless double-beta decay in upcoming experiments will establish that the neutrinos are Majorana particles, the underlying new physics responsible for this decay can only be constrained if the theoretical predictions of the rate are substantially refined. This talk demonstrates the roadmap in connecting the underlying high-scale theory to the corresponding nuclear matrix elements, focusing mainly on the nucleonic matrix elements in the simplest extension of Standard Model in which a light Majorana neutrino is mediating the process. The role of lattice QCD and effective field theory in this program, in particular, the prospect of a direct matching of the nn to pp amplitude to lattice QCD will be discussed. As a first step towards this goal, the results of the first lattice QCD calculation of the relevant matrix element for neutrinofull double-beta decay will be presented, albeit with unphysical quark masses, along with important lessons that could impact the calculations of nuclear matrix elements involved in double-beta decays of realistic nuclei.
T-odd momentum correlation in radiative {beta} decay
Energy Technology Data Exchange (ETDEWEB)
Gardner, Susan, E-mail: gardner@pa.uky.edu; He, Daheng [University of Kentucky, Department of Physics and Astronomy (United States)
2013-03-15
The triple-product correlations observable in ordinary neutron or nuclear beta decay are all naively T violating and can connect, through an assumption of CPT invariance, to constraints on sources of CP violation beyond the Standard Model. They are also spin dependent. In this context the study of radiative beta decay opens a new possibility, in that a triple-product correlation can be constructed from momenta alone. Consequently its measurement would constrain new spin-independent sources of CP violation. We will describe these in light of the size of the triple momentum correlation in the decay rate arising from electromagnetic final-state interactions in the Standard Model. Our expression for the corresponding T-odd asymmetry is exact in O({alpha}) up to terms of recoil order, and we evaluate it numerically under various kinematic conditions. We consider the pattern of the asymmetries in nuclear {beta} decays and show that the asymmetry can be suppressed in particular cases, facilitating searches for new sources of CP violation in such processes.
Double beta decay: recent developments and projections
International Nuclear Information System (INIS)
Avignone, F.T. III; Brodzinski, R.L.; Brown, D.P.; Evans, J.C. Jr.; Hensley, W.K.; Reeves, J.H.; Wogman, N.A.
1983-08-01
A report of recent events in both theoretical and experimental aspects of double beta decay is given. General theoretical considerations, recent developments in nuclear structure theory, geochronological determinations of half lives and ratios as well as laboratory experiments are discussed with emphasis on the past three years. Some projections are given. 28 references
Double beta decay: A theoretical overview
International Nuclear Information System (INIS)
Rosen, S.P.
1988-01-01
This paper reviews the theoretical possibility of double beta decay. The titles of the main sections of this paper are: Nuclear physics setting; Particle physics requirements; Kinematical features of the decay modes; Nuclear matrix elements; the Shell model and two-neutrino decay; Quasi-particle random phase approximation; and Future considerations. 18 refs., 7 tabs
Nuclear aspects of double-beta decay
International Nuclear Information System (INIS)
Stoica, S.; Paun, V.
2002-01-01
Calculations of the neutrinoless double-beta decay (0νββ) matrix elements are performed with the second quasi random phase approximation (SQRPA) method for several nuclei. The results display a weak dependence on the single particle basis used and the Ikeda sum rule is fulfilled with good accuracy. Comparing our calculations with similar ones performed with other QRPA-based methods we estimate the accuracy of these methods in the prediction of the (0νββ) decay matrix elements and neutrino mass parameter, which is settled to about 50% from their calculated values. Taking the most recent experimental limits for the neutrinoless double beta decay half-lives, we also deduced new limits for the neutrino mass parameter. (authors)
Double beta decays and neutrino masses
International Nuclear Information System (INIS)
Ejiri, Hiro
2006-01-01
Neutrino-less double beta decays(0νββ) are of great interest for studying the Majorana nature of ν's and the absolute ν-mass scale. The present report is a brief review of the 0νββ studies with emphasis on future experiments with the mass sensitivity of an order of 25∼100 meV and on experimental probes for investigating 0νββ nuclear matrix elements
Tables of double beta decay data
International Nuclear Information System (INIS)
Tretyak, V.I.
1995-01-01
A compilation of experimental data on double beta decay is presented. The tables contain the most stringent known experimental limits or positive results of 2β transitions of 69 natural nuclides to ground and excited states of daughter nuclei for different channels (2β - ; 2β + ; εβ + ; 2ε) and modes (0ν; 2ν; 0νM) of decay. (authors). 189 refs., 9 figs., 3 tabs
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.
Limits on Tensor Coupling from Neutron $\\beta$-Decay
Pattie Jr, Robert W.; Hickerson, Kevin P.; Young, Albert R.
2013-01-01
Limits on the tensor couplings generating a Fierz interference term, b, in mixed Gamow-Teller Fermi decays can be derived by combining data from measurements of angular correlation parameters in neutron decay, the neutron lifetime, and $G_{\\text{V}}=G_{\\text{F}} V_{ud}$ as extracted from measurements of the $\\mathcal{F}t$ values from the $0^{+} \\to 0^{+}$ superallowed decays dataset. These limits are derived by comparing the neutron $\\beta$-decay rate as predicted in the standard model with t...
Neutrinoless double beta decay and lepton flavor violation
International Nuclear Information System (INIS)
Cirigliano, V.; Kurylov, A.; Vogel, P.; Ramsey-Musolf, M.J.
2004-01-01
We point out that extensions of the standard model with low scale (∼TeV) lepton number violation (LNV) generally lead to a pattern of lepton flavor violation (LFV) experimentally distinguishable from the one implied by models with grand unified theory scale LNV. As a consequence, muon LFV processes provide a powerful diagnostic tool to determine whether or not the effective neutrino mass can be deduced from the rate of neutrinoless double beta decay. We discuss the role of μ→eγ and μ→e conversion in nuclei, which will be studied with high sensitivity in forthcoming experiments
Exchange effects in double beta decay
International Nuclear Information System (INIS)
Stephenson, G.J. Jr.; Goldman, T.; Maltman, K.R.; Schmidt, K.E.
1988-01-01
The motivation underlying the resurgence of interest in double beta decay is the hope that the observation of or limits on the 0-neutrino mode will provide information about the nature of the neutrino. This clearly requires confidence in the nuclear matrix elements involved in the transition. The shell model calculations do not agree well with the geochemical values for 130 Te, which has lead to a spate of papers offering specific fixes for the problem. In this contribution we shall not comment on any of the specific nuclear calculations, rather we make some remarks which should be relevant to any model calculation
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.
Simulated progress in double-beta decay
International Nuclear Information System (INIS)
Miley, H.S.; Arthur, R.J.; Avignone, F.T.
1993-09-01
A Monte Carlo code has been developed to accurately simulate double-beta decay measurements. Coincident gamma rays, beta spectra, and angular correlations have been added to adequately simulate a complete 100 Mo nuclear decay and provide corrections to experimentally determined detector efficiencies. This code has been used to strip certain low-background spectra obtained in the Homestake gold mine in Lead, SD, for the purpose of extremely sensitive materials assay for the construction of new, large, enriched germanium detectors. Assays as low as 9 μBq/g of 210 Pb in lead shielding were obtained
Weak interaction studies from nuclear beta decay
International Nuclear Information System (INIS)
Morita, M.
1981-01-01
The studies performed at the theoretical nuclear physics division of the Laboratory of Nuclear Studies, Osaka University, are reported. Electron spin density and internal conversion process, nuclear excitation by electron transition, beta decay, weak charged current, and beta-ray angular distributions in oriented nuclei have been studied. The relative intensity of internal conversion electrons for the case in which the radial wave functions of orbital electrons are different for electron spin up and down was calculated. The calculated value was in good agreement with the experimental one. The nuclear excitation following the transition of orbital electrons was studied. The calculated probability of the nuclear excitation of Os 189 was 1.4 x 10 - 7 in conformity with the experimental value 1.7 x 10 - 7 . The second class current and other problems on beta-decay have been extensively studied, and described elsewhere. Concerning weak charged current, the effects of all induced terms, the time component of main axial vector, all partial waves of leptons, Coulomb correction for the electrons in finite size nuclei, and radiative correction were studied. The beta-ray angular distribution for the 1 + -- 0 + transition in oriented B 12 and N 12 was investigated. In this connection, investigation on the weak magnetism to include all higher order corrections for the evaluation of the spectral shape factors was performed. Other works carried out by the author and his collaborators are also explained. (Kato, T.)
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.
A background free double beta decay experiment
International Nuclear Information System (INIS)
Giomataris, I
2011-01-01
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 the high-pressure 136 Xe emitter where 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 the use of the Spherical Proportional Counter that provides, using a single read-out channel, two delayed signals from ionization and Cherenkov light. In solid-state double beta decay emitters, because of its higher density, the considered process is out of energy range. An escape will be the fabrication of double decay emitters having lower density by using for instance the aerogel technique. It is surprising that a technology used for particle identification in high-energy physics becomes a powerful tool for rejecting backgrounds in such low-energy experiments.
Double beta decay in gauge theories
International Nuclear Information System (INIS)
Vergados, J.D.
2002-01-01
Neutrinoless double beta decay is a very important process both from the particle and nuclear physics point of view. From the elementary particle point of view it pops up in almost every model, giving rise among others to the following mechanisms: a) The traditional contributions like the light neutrino mass mechanism as well as the j L - j R leptonic interference (λ and η terms). b) The exotic R-parity violating supersymmetric (SUSY) contributions. From the nuclear physics point of view it is challenging, because: 1) The nuclei, which can undergo double beta decay, have complicated nuclear structure. 2) The energetically allowed transitions are suppressed (exhaust a small part of all the strength). 3) Since in some mechanisms the intermediate particles are very heavy one must cope with the short distance behavior of the transition operators. 4) The intermediate momenta involved are quite high and one has to consider momentum dependent terms of the nucleon current. Taking the above effects into account from the experimental limits on the interesting nuclei A=76, 82, 96, 100, 116, 128, 130, 136 and 150, we have extracted new limits on the various lepton violating parameters. In particular we get a stringent limit on the R-parity violating parameter λ' 111 -4 . (author)
Isospin and quarks in nuclear beta-decay
International Nuclear Information System (INIS)
Wilkinson, D.H.
1991-04-01
This paper exposes in some detail the technical problems relating to the extraction of the vector coupling constant from the beta decay of complex nuclei. It also considers the extraction of the axial coupling constant from the beta-decay of the neutron. The internal consistency of all data relating to beta-decay, including that of the muon, is also examined, within the standard model, with a view to the possible intervention of W R . (Author) 52 refs., 4 figs., 2 tabs
International Nuclear Information System (INIS)
Ritchie, Burke
2006-01-01
The Hamiltonian for Dirac's second-order equation depends nonlinearly on the potential V and the energy E. For this reason the magnetic contribution to the Hamiltonian for s-waves, which has a short range, is attractive for a repulsive Coulomb potential (V>0) and repulsive for an attractive Coulomb potential (V 2 . Usually solutions are found in the regime E=mc 2 +ε , where except for high Z, ε 2 . Here it is shown that for V>0 the attractive magnetic term and the linear repulsive term combine to support a bound state near E=0.5mc 2 corresponding to a binding energy E b =-ε =0.5mc 2
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.
Double beta decay: a new formalism
International Nuclear Information System (INIS)
Hirsch, J.; Krmpotic, F.
1990-01-01
A study is made of the validity of those methods consisting in an average of solutions from initial and final solutions within the quasi-particle random phase approximation (QRPA) for double beta decay. A new method is developed that works with a single QRPA equation for the intermediate nucleus in which the correlations of the ground state for β - transitions are β + and vice versa. Numerical results agree in the different formulations, which avails the known averaging procedures while showing the greater operative simplicity of the proposed method for the case of the two neutrino mode in which the diagonalization process may be substituted by a matrix inversion. (Author). 13 refs., 1 fig., 1 tab
Double beta decay searches with thermal detectors
International Nuclear Information System (INIS)
Pirro, Stefano
2006-01-01
Double beta decay searches have become more and more important in the last few years. The 'second generation' experiments will allow to explore the inverse hierarchy region but, due to the uncertainties in the nuclear matrix elements, none of them will be able to cover completely the allowed region. Thus the need to investigate different DBD emitters becomes more important. The bolometric technique is only one able to study different nuclei with the proper energy resolution, key point for the future experiments. The possibility to reject the natural background arising from fast neutrons and alpha particles was recently directly proved with thermal bolometers, using the double read out (heat and scintillation). This new technique offers the possibility to reach background levels two orders of magnitude smaller with respect to the ones of the next planned experiments, aiming the possibility to investigate direct hierarchy region. (author)
Improved limits on beta(-) and beta(-) decays of Ca-48
Czech Academy of Sciences Publication Activity Database
Bakalyarov, A.; Balysh, A.; Barabash, AS.; Beneš, P.; Briancon, C.; Brudanin, V. B.; Čermák, P.; Egorov, V.; Hubert, F.; Hubert, P.; Korolev, NA.; Kosjakov, VN.; Kovalík, Alojz; Lebedev, NA.; Novgorodov, A. F.; Rukhadze, NI.; Štekl, NI.; Timkin, VV.; Veleshko, IE.; Vylov, T.; Umatov, VI.
2002-01-01
Roč. 76, č. 9 (2002), s. 545-547 ISSN 0021-3640 Institutional research plan: CEZ:AV0Z1048901 Keywords : beta decay * double beta decay * Ca-48 Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.483, year: 2002
International Nuclear Information System (INIS)
Zahn, Guilherme Soares
2006-01-01
In this work, the excited levels of 193 Ir populated by the beta - decay of 193 Os (T 1/2 ∼ 30h) were investigated. For that purpose, ∼ 5 mg samples of 99%-enriched 192 Os were irradiated under a thermal neutron flux of ∼ 10 12 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 (δ Ln+1 /L n ) 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 193 Ir. (author)
Neutrinoless double beta decay in Gerda
Grabmayr, Peter; Gerda Collaboration
2015-10-01
The Germanium Detector Array (Gerda) experiment searches for the neutrinoless double beta decay in 76Ge. This lepton number violating process is predicted by extensions of the standard model. Gerda follows a staged approach by increasing mass and lowering the background level from phase to phase. Gerda is setup at the Gran Sasso underground laboratory of INFN, Italy. An array of high-purity germanium detectors is lowered directly in liquid argon for shielding and cooling. Further background reduction is achieved by an instrumented water buffer. In Phase I an exposure of 21.6 kg yr was collected at a background level of 10-2 cts/(keV kg yr). The lower limit on the half-life of 76Ge > 2 . 1 .1025 yr (90% C.L.) has been published. Further analyses search for decay into excited states or the accompanied Majoron decay. Presently, Phase II is in preparation which intends to reach a background level of 10-3 cts/(keV kg yr) and to increase the exposure to 100 kg yr. About 20 kg of novel thick-window BEGe (Broad Energy Germanium) detectors will be added and the liquid argon will be instrumented. The status of Phase II preparation and results from the commissioning runs will be presented as well as some further results from Phase I.
Theory of neutrinoless double beta decay
Vergados, J.D.; Simkovic, F.
2012-01-01
Neutrinoless double beta decay, which is a very old and yet elusive process, is reviewed. Its observation will signal that lepton number is not conserved and the neutrinos are Majorana particles. More importantly it is our best hope for determining the absolute neutrino mass scale at the level of a few tens of meV. To achieve the last goal certain hurdles have to be overcome involving particle, nuclear and experimental physics. Nuclear physics is important for extracting the useful information from the data. One must accurately evaluate the relevant nuclear matrix elements, a formidable task. To this end, we review the sophisticated nuclear structure approaches recently been developed, which give confidence that the needed nuclear matrix elements can be reliably calculated. From an experimental point of view it is challenging, since the life times are long and one has to fight against formidable backgrounds. If a signal is found, it will be a tremendous accomplishment. Then, of course, the real task is going ...
International Nuclear Information System (INIS)
Reiss, H.R.
1984-01-01
The negative conclusion in the Comment of Becker, Schlicher, and Scully about electromagnetic enhancement of beta decay is shown to be faulty. They have found an algebraic oversight in my paper, but correction of that oversight yields results strongly resembling the original. Becker, Schlicher, and Scully fail to find this. They then conduct an analysis which is highly implicit and incomplete. In attempting to analyze their very complicated expressions they claim not to find significant electromagnetic effects. Yet they also lose completely the electron retardation term of conventional forbidden beta decay. When they attempt to explain the difference between their results and mine, they misconstrue the momentum-translation technique and end up in a logical contradiction. They attempt also to apply a ''no-go'' theorem applicable only to plane-wave particles to my theory, which is built around the use of bound-state nuclear wave functions. This makes the no-go theorem inapplicable
Meson exchange currents and two neutrino double beta decay
International Nuclear Information System (INIS)
Simkovic, F.
1995-01-01
By using a field theory approach a detailed analysis of the two neutrino double beta decay amplitude has been performed. We have shown that the summation over the intermediate nuclear states in the present two neutrino double beta decay studies corresponds to a summation over a class of meson exchange diagrams. We offer some arguments showing that the two nucleon mechanism considered at present does not provide the main contribution to the two neutrino double beta decay amplitude. A new electron-gamma exchange mechanism for this process is suggested. 31 refs., 1 fig
Introductory remarks on double beta decay and nuclear physics
International Nuclear Information System (INIS)
Rosen, S.P.
1986-01-01
The particle physics aspects of double beta decay and the theory of the phenomenon are briefly reviewed. The distinction between Dirac and Majorana neutrinos is drawn by comparing the neutrino that accompanies a negatively charged lepton in some hadronic decay process with that which accompanies a positively charged lepton in some other decay process. Two modes of double beta decay are examined - one emitting two neutrinos and the other emitting no neutrinos. What can be learned from the existing data on double beta decay is considered, de-emphasizing the question of bounds on neutrino mass and concentrating on the properties of the phenomenon itself. Possible future experiments are anticipated. 16 refs
Tests of the standard electroweak model in beta decay
Energy Technology Data Exchange (ETDEWEB)
Severijns, N.; Beck, M. [Universite Catholique de Louvain (UCL), Louvain-la-Neuve (Belgium); Naviliat-Cuncic, O. [Caen Univ., CNRS-ENSI, 14 (France). Lab. de Physique Corpusculaire
2006-05-15
We review the current status of precision measurements in allowed nuclear beta decay, including neutron decay, with emphasis on their potential to look for new physics beyond the standard electroweak model. The experimental results are interpreted in the framework of phenomenological model-independent descriptions of nuclear beta decay as well as in some specific extensions of the standard model. The values of the standard couplings and the constraints on the exotic couplings of the general beta decay Hamiltonian are updated. For the ratio between the axial and the vector couplings we obtain C{sub A},/C{sub V} = -1.26992(69) under the standard model assumptions. Particular attention is devoted to the discussion of the sensitivity and complementarity of different precision experiments in direct beta decay. The prospects and the impact of recent developments of precision tools and of high intensity low energy beams are also addressed. (author)
Tests of the standard electroweak model in beta decay
International Nuclear Information System (INIS)
Severijns, N.; Beck, M.; Naviliat-Cuncic, O.
2006-05-01
We review the current status of precision measurements in allowed nuclear beta decay, including neutron decay, with emphasis on their potential to look for new physics beyond the standard electroweak model. The experimental results are interpreted in the framework of phenomenological model-independent descriptions of nuclear beta decay as well as in some specific extensions of the standard model. The values of the standard couplings and the constraints on the exotic couplings of the general beta decay Hamiltonian are updated. For the ratio between the axial and the vector couplings we obtain C A ,/C V = -1.26992(69) under the standard model assumptions. Particular attention is devoted to the discussion of the sensitivity and complementarity of different precision experiments in direct beta decay. The prospects and the impact of recent developments of precision tools and of high intensity low energy beams are also addressed. (author)
Method and apparatus for induced nuclear beta decay
International Nuclear Information System (INIS)
Reiss, H.
1986-01-01
This invention relates to a method and apparatus for inducing beta decay transition that are normally inhibited by angular momentum or parity considerations. According to one aspect of this invention a method of inducing nuclear beta decay transition comprises providing a medium which includes atomic nuclei that have forbidden beta decay transition in which the initial and final nuclear states do not have the same intrinsic parity or have total angular momenta which differ by more than one quantum unit of angular momentum, and applying to the medium an electromagnetic field which has an intensity sufficient to provide the angular momentum or intrinsic parity necessary to overcome the forbiddenness of the beta decay transition of the atomic nuclei, thereby to induce the beta decay transitions. According to another aspect of this invention an apparatus for inducing beta decay transition comprises a medium which includes atomic nuclei that have forbidden beta decay transitions in which the initial and final nuclear states do not have the same intrinsic parity or have total angular momenta which differ by more than one quantum unit of angular momentum, field producing means for producing an electromagnetic field in the medium and means for energising the field producing means to establish the field at an intensity sufficient to provide the angular momentum or intrinsic parity necessary to overcome the forbiddenness of the beta decay transitions of the atomic nuclei. The energy released in these induced nuclear transition is useful for the controlled production of power. The induced beta dacay transitions are also useful to reduce the halflives of long-lived fission product wastes from conventional nuclear fission power plants
Study of the $\\beta$-decay of $^{20}$Mg
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.
Can $\\beta$-decay probe excited state halos?
2002-01-01
In the first experiment at the newly constructed ISOLDE Facility the first-forbidden $\\beta$-decay of $^{17}$Ne into the first excited state of $^{17}$F has been measured. It is a factor two faster than the corresponding mirror decay and thus gives one of the largest recorded asymmetries for $\\beta$-decays feeding bound final states. Shell-model calculations can only reproduce the asymmetry if the halo structure of the $^{17}$F state is taken into account.
On the nuclear double beta decay: microscopic description
International Nuclear Information System (INIS)
Civitarese, Osvaldo
1989-01-01
This paper is devoted to the discussion of some problems related with microscopic descriptions of the nuclear double beta decay. It has been organized in the following order: 1) Review of the experimental situation; 2) Brief discussion of the theoretical aspects related to the current algebra, weak interaction, neutrino and majoron's status and 3) Elements of the standard nuclear theory involved in the calculation of transition densities for the nuclear double beta decay. (Author) [es
Schulz, Marc Daniel; Dusuel, Sébastien; Vidal, Julien
2016-11-01
We discuss the emergence of bound states in the low-energy spectrum of the string-net Hamiltonian in the presence of a string tension. In the ladder geometry, we show that a single bound state arises either for a finite tension or in the zero-tension limit depending on the theory considered. In the latter case, we perturbatively compute the binding energy as a function of the total quantum dimension. We also address this issue in the honeycomb lattice where the number of bound states in the topological phase depends on the total quantum dimension. Finally, the internal structure of these bound states is analyzed in the zero-tension limit.
Relativistic pn-QRPA to the double beta decay
International Nuclear Information System (INIS)
Conti, Claudio de; Krmpotic, F.; Carlson, Brett Vern
2010-01-01
Full text: In nature there are about 50 nuclear systems where the single beta-decay is energetically forbidden, and double- beta decay turns out to be only possible mode of disintegration. It is the nuclear pairing force which causes such an 'anomaly', by making the mass of the odd-odd isobar, (N - 1;Z + 1), to be greater than the masses of its even-even neighbors, (N;Z) and (N - 2;Z +2). The modes by which the double-beta decay can take place are connected with the neutrino and antineutrino distinction. In case the lepton number is strictly conserved the neutrino is a Dirac fermion and the two-neutrino mode is the only possible mode of disintegration. On the other hand, if this conservation is violated, the neutrino is a Majorana particle and neutrinoless double-beta decay also can occur. Both two-neutrino and neutrinoless double-beta decay processes have attracted much attention, because a comparison between experiment and theory for the first, provides a measure of confidence one may have in the nuclear wave function employed for extracting the unknown parameters from neutrinoless lifetime measurements. The proton-neutron (pn) quasiparticle random phase approximation (QRPA) has turned out be the most simple model for calculating the nuclear wave function involved in the double-beta decay transitions. In this work the transition matrix elements for 0 + -> 0 + double-beta decay are calculated for 48 Ca, 76 Ge, 82 Se, 100 Mo, 128 Te and 130 Te nuclei, using a relativistic pn-QRPA based on Hartree-Bogoliubov approximation to the single-particle motion. (author)
Relativistic pn-QRPA to the double beta decay
International Nuclear Information System (INIS)
Conti, Claudio de; Krmpotic, Francisco; Carlson, Brett Vern
2011-01-01
Full text: In nature there are about 50 nuclear systems where the single beta-decay is energetically forbidden, and double-beta decay turns out to be only possible mode of disintegration. It is the nuclear pairing force which causes such an 'anomaly', by making the mass of the odd-odd isobar, (N - 1;Z + 1), to be greater than the masses of its even-even neighbors, (N;Z) and (N - 2;Z +2). The modes by which the double-beta decay can take place are connected with the neutrino and antineutrino distinction. In case the lepton number is strictly conserved the neutrino is a Dirac fermion and the two-neutrino mode is the only possible mode of disintegration. On the other hand, if this conservation is violated, the neutrino is a Majorana particle and neutrinoless double-beta decay also can occur. Both two-neutrino and neutrinoless double-beta decay processes have attracted much attention, because a comparison between experiment and theory for the first, provides a measure of confidence one may have in the nuclear wave function employed for extracting the unknown parameters from neutrinoless lifetime measurements. The proton-neutron (pn) quasiparticle random phase approximation (QRPA) has turned out be the most simple model for calculating the nuclear wave function involved in the double-beta decay transitions. In this work the transition matrix elements for 0 + → 0 + double-beta decay are calculated for 48 Ca, 76 Ge, 82 Se, 100 Mo, 128 Te and 130 Te nuclei, using a relativistic pn-QRPA based on Hartree-Bogoliubov approximation to the single-particle motion. (author)
Double Charge Exchange Reactions and Double Beta Decay
Auerbach, N.
2018-05-01
The subject of this presentation is at the forefront of nuclear physics, namely double beta decay. In particular one is most interested in the neutrinoless process of double beta decay, when the decay proceeds without the emission of two neutrinos. The observation of such decay would mean that the lepton conservation symmetry is violated and that the neutrinos are of Majorana type, meaning that they are their own anti-particles. The life time of this process has two unknowns, the mass of the neutrino and the nuclear matrix element. Determining the nuclear matrix element and knowing the cross-section well will set limits on the neutrino mass. There is a concentrated effort among the nuclear physics community to calculate this matrix element. Usually these matrix elements are a very small part of the total strength of the transition operators involved in the process. There is no simple way to “calibrate” the nuclear double beta decay matrix element. The double beta decay is a double charge exchange process, therefore it is proposed that double charge exchange reactions using ion projectiles on nuclei that are candidates for double beta decay, will provide additional necessary information about the nuclear matrix elements.
International Nuclear Information System (INIS)
Zouzou, S.
1986-01-01
In the framework of simple non-relativistic potential models, we examine the system consisting of two quarks and two antiquarks with equal or unequal masses. We search for possible bound states below the threshold for the spontaneous dissociation into two mesons. We solve the four body problem by empirical or systematic variational methods and we include the virtual meson-meson components of the wave function. With standard two-body potentials, there is no proliferation of multiquarks. With unequal quark masses, we obtain however exotic (anti Qanti Qqq) bound states with a baryonic antidiquark-quark-quark structure very analogous to the heavy flavoured (Q'qq) baryons. (orig.)
Calculating beta decay in the deformed self-consistent quasiparticle random phase approximation
Energy Technology Data Exchange (ETDEWEB)
Engel, Jonathan, E-mail: engelj@physics.unc.edu [Department of Physics and Astronomy, University of North Carolina, Chapel Hill, NC 27599-3255 (United States); Mustonen, M. T., E-mail: mika.mustonen@yale.edu [Department of Physics and Astronomy, University of North Carolina, Chapel Hill, NC 27599-3255 (United States); Center for Theoretical Physics, Sloane Physics Laboratory, Yale University, New Haven, CT 06052 (United States)
2016-06-21
We discuss a recent global calculation of beta-decay rates in the self-consistent Skyrme quasiparticle random phase approximation (QRPA), with axially symmetric nuclear deformation treated explicitly. The calculation makes makes use of the finite-amplitude method, first proposed by Nakatsukasa and collaborators, to reduce computation time. The results are comparable in quality to those of several other global QRPA calculations. The QRPA may have reached the limit of its accuracy.
Search for new physics with neutrinoless double beta decay
International Nuclear Information System (INIS)
Klapdor-Kleingrothaus, H.V.; Baudis, L.; Hellmig, J.; Hirsch, M.; Kolb, S.; Paes, H.; Ramachers, Y.
1999-01-01
Neutrinoless double beta decay (0νββ) is one of the most sensitive approaches to test particle physics beyond the standard model. During the last years, besides the most restrictive limit on the effective Majorana neutrino mass, the analysis of new contributions by the Heidelberg group led to bounds on left-right-symmetric models, leptoquarks and R-parity violating models competitive to recent accelerator limits, which are of special interest in view of the HERA anomaly at large Q 2 and x. These new results deduced from the Heidelberg-Moscow double beta decay experiment are reviewed. Also an outlook on the future of double beta decay, the GENIUS proposal, is given
The {beta}-decay Paul trap: A radiofrequency-quadrupole ion trap for precision {beta}-decay studies
Energy Technology Data Exchange (ETDEWEB)
Scielzo, N.D., E-mail: scielzo1@llnl.gov [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Li, G. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Department of Physics, McGill University, Montreal, Quebec, Canada H3A 2T8 (Canada); Sternberg, M.G.; Savard, G. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Department of Physics, University of Chicago, Chicago, Illinois 60637 (United States); Bertone, P.F. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Buchinger, F. [Department of Physics, McGill University, Montreal, Quebec, Canada H3A 2T8 (Canada); Caldwell, S. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Department of Physics, University of Chicago, Chicago, Illinois 60637 (United States); Clark, J.A. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Crawford, J. [Department of Physics, McGill University, Montreal, Quebec, Canada H3A 2T8 (Canada); Deibel, C.M. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824 (United States); Fallis, J. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba, Canada R3T 2N2 (Canada); Greene, J.P. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); and others
2012-07-21
The {beta}-decay Paul trap is a linear radiofrequency-quadrupole ion trap that has been developed for precision {beta}-decay studies. The design of the trap electrodes allows a variety of radiation detectors to surround the cloud of trapped ions. The momentum of the low-energy recoiling daughter nuclei following {beta} decay is negligibly perturbed by scattering and is available for study. This advantageous property of traps allows the kinematics of particles that are difficult or even impossible to directly detect to be precisely reconstructed using conservation of energy and momentum. An ion-trap system offers several advantages over atom traps, such as higher trapping efficiencies and element-independent capabilities. The first precision experiment using this system is a measurement of {beta}-decay angular correlations in the decay of {sup 8}Li performed by inferring the momentum of the neutrino from the kinematic shifts imparted to the breakup {alpha} particles. Many other {beta}-decay studies that would benefit from a determination of the nuclear recoil can be performed with this system.
Bound states of 'dressed' particles
International Nuclear Information System (INIS)
Shirokov, M.I.
1994-01-01
A new approach to the problem of bound states in relativistic quantum field theories is suggested. It uses the creation - destruction operators of 'dresses' particles which have been granted by Faddeev's (1963) 'dressing' formalism. Peculiarities of the proposed approach as compared to the known ones are discussed. 8 refs. (author)
Future of double beta decay and dark matter searches - GENIUS
International Nuclear Information System (INIS)
Klapdor-Kleingrothaus, H. V.; Baudis, L.; Heusser, G.; Krivosheina, I. V.; Kolb, S.; Majorovits, B.; Nabi, J.-U.; Paes, H.
1999-01-01
The recent results from the HEIDELBERG-MOSCOW experiment have demonstrated the large potential of double beta decay to search for new physics beyond the standard model. To increase further by a major step the present sensitivity for double beta decay and dark matter searches, we describe here a project, proposed recently [1], which would operate one tonne of 'naked' enriched germanium-detectors in liquid nitrogen as shielding in an underground set-up (GENIUS). It improves the sensitivity of neutrino masses to 0.01 eV. A 10 tonne version would probe neutrino masses even down to 10 -3 eV
Nuclear beta decay far from stability and astrophysics
International Nuclear Information System (INIS)
Klapdor, H.V.
1988-01-01
Beta decay data of nuclei far from stability are one of the most important nuclear physics input for the understanding of the element systhesis in the universe and determination of the age of the universe from cosmochronometers and by the latter have implications also for cosmology. The present status of theoretical predictions of beta decay far from stability will be reviewed and the impact on the above astrophysical questions will be outlined. First results of second generation microscopic calculations of β F half lives, which are at present in progress, will be presented. (orig.)
Neutrinoless Double Beta Decay with CUORE-0: Physics Results and Detector Performance
Canonica, L.
2016-08-01
The CUORE-0 experiment searches for neutrinoless double beta decay in ^{130}Te. It consists of an array of 52 tellurium dioxide crystals, operated as bolometers at a temperature of 10 mK, with a total mass of about 39 kg of TeO_2. CUORE-0 has been built to test the performance of the upcoming CUORE experiment and represents the largest ^{130}Te bolometric setup currently in operation. This experiment has been running in the Gran Sasso National Laboratory, Italy, since March 2013. We report the results of a search for neutrinoless double beta decay in 9.8 kg years ^{130}Te exposure, which allowed us to set the most stringent limit to date on this half-life. The performance of the detector in terms of background rate and energy resolution are also reported.
Binding energies of two deltas bound states
International Nuclear Information System (INIS)
Sato, Hiroshi; Saito, Koichi.
1982-06-01
Bound states of the two-deltas system are investigated by employing the realistic one boson exchange potential. It is found that there exist many bound states in each isospin channel and also found that the tensor interaction plays important role in producing these bound states. Relationship between these bound states and dibaryon resonances is discussed. (J.P.N.)
Sensitivity and Discovery Potential of CUORE to Neutrinoless Double-Beta Decay
Energy Technology Data Exchange (ETDEWEB)
Alessandria, F; Ardito, R; Artusa, DR; III, FTA; Azzolini, O; Balata, M; Banks, TI; Bari, G; Beeman, J; Bellini, F; Bersani, A; Biassoni, M; Bloxham, T; Brofferio, C; Bucci, C; Cai, XZ; Canonica, L; Cao, X; Capelli, S; Carbone, L; Cardani, L; Carrettoni, M; Casali, N; Chiesa, D; Chott, N; Clemenza, M; Cosmelli, C; Cremonesi, O; Creswick, RJ; Dafinei, I; Dally, A; Datskov, V; Biasi, AD; Deninno, MM; Domizio, SD; Vacri, MLD; Ejzak, L; Faccini, R; Fang, DQ; Farach, HA; Faverzani, M; Fernandes, G; Ferri, E; Ferroni, F; Fiorini, E; Franceschi, MA; Freedman, SJ; Fujikawa, BK; Giachero, A; Gironi, L; Giuliani, A; Goett, J; Gorla, P; Gotti, C; Guardincerri, E; Gutierrez, TD; Haller, EE; Han, K; Heeger, KM; Huang, HZ; Kadel, R; Kazkaz, K; Keppel, G; Kogler, L; Kolomensky, YG; Lenz, D; Li, YL; Ligi, C; Liu, X; Ma, YG; Maiano, C; Maino, M; Martinez, M; Maruyama, RH; Mei, Y; Moggi, N; Morganti, S; Napolitano, T; Newman, S; Nisi, S; Nones, C; Norman, EB; Nucciotti, A; O' Donnell, T; Orio, F; Orlandi, D; Ouellet, JL; Pallavicini, M; Palmieri, V; Pattavina, L; Pavan, M; Pedretti, M; Pessina, G; Piperno, G; Pirro, S; Previtali, E; Rampazzo, V; Rimondi, F; Rosenfeld, C; Rusconi, C; Sala, E; Sangiorgio, S; Scielzo, ND; Sisti, M; Smith, AR; Stivanello, F; Taffarello, L; Tenconi, M; Tian, WD; Tomei, C; Trentalange, S; Ventura, G; Vignati, M; Wang, BS; Wang, HW; Wise, T; Woodcraft, A; Zanotti, L; Zarra, C; Zhu, BX; Zucchelli, S
2017-07-06
We present a study of the sensitivity and discovery potential of CUORE, a bolometric double-beta decay experiment under construction at the Laboratori Nazionali del Gran Sasso in Italy. Two approaches to the computation of experimental sensitivity for various background scenarios are presented, and an extension of the sensitivity formulation to the discovery potential case is also discussed. Assuming a background rate of 10^{-2} cts/(keV kg y), we find that, after 5 years of live time, CUORE has a 1 sigma sensitivity to the neutrinoless double-beta decay half-life of T$0v\\atop{1/2}$(1θ) = 1.6 \\times 10^{26} y and thus a potential to probe the effective Majorana neutrino mass down to 40-100 meV; the sensitivity at 1.64 sigma, which corresponds to 90% C.L., will be T$0v\\atop{1/2}$(1.64θ) = 9.5 \\times 10^{25} y. This range is compared with the claim of observation of neutrinoless double-beta decay in ^{76}Ge and the preferred range of the neutrino mass parameter space from oscillation results.
Warm Dark Matter Sterile Neutrinos in Electron Capture and Beta Decay Spectra
Directory of Open Access Journals (Sweden)
O. Moreno
2016-01-01
Full Text Available We briefly review the motivation to search for sterile neutrinos in the keV mass scale, as dark matter candidates, and the prospects to find them in beta decay or electron capture spectra, with a global perspective. We describe the fundamentals of the neutrino flavor-mass eigenstate mismatch that opens the possibility of detecting sterile neutrinos in such ordinary nuclear processes. Results are shown and discussed for the effect of heavy neutrino emission in electron capture in Holmium 163 and in two isotopes of Lead, 202 and 205, as well as in the beta decay of Tritium. We study the deexcitation spectrum in the considered cases of electron capture and the charged lepton spectrum in the case of Tritium beta decay. For each of these cases, we define ratios of integrated transition rates over different regions of the spectrum under study and give new results that may guide and facilitate the analysis of possible future measurements, paying particular attention to forbidden transitions in Lead isotopes.
Nuclear transparency and double beta decay of molybdenum 100
International Nuclear Information System (INIS)
Nicholson, H.W.
1992-08-01
Data taking is now complete on a double beta decay experiment which has been carried out with collaborators from the Lawrence Berkeley Laboratory, the University of New Mexico, and the Idaho National Engineering Laboratory, and work is continuing on a second collaborative experiment, AGS experiment 850 at the Brookhaven National Laboratory to study nuclear color transparency. In March, the experimental apparatus used to search for double beta decay in molybdenum 100 in the Consil silver mine in Osburn, Idaho was dismantled, and the data analysis is in its final stages. No evidence has been seen for the O + → O + mode of zero neutrino double beta decay collaborators with a 1σ lifetime limit of 3 x 10 22 years. This limit is 7.5 times greater than the limit we published previously in Physical Review Letters in 1989. Backgrounds have been simulated and fits are currently underway to a simulated O + → 2 + mode of zero neutrino double beta decay to improve on a very preliminary 1σ lifetime limit of 2.3 x 10 21 years presented at the April, 1992 meeting of the APS in Washington. A scintillating fiber detector with three Hamamatsu, H4140, 256 channel multianode phototubes has been built, instrumented, and tested in the May--July 1992 run in the EVA detector at Brookhaven Laboratory's AGS. Preliminary results from this detector have been disappointing. it is likely that the detector will have to be substantially redesigned before the 1993 AGS run
Results on neutrinoless double beta decay from GERDA phase I
CERN. Geneva
2013-01-01
After motivating searches of double beta decay and lepton number violation details about the construction, operation and analysis of GERDA will be given. Results of the recently completed phase I of data taking will then be presented and interpreted. Finally an outlook on future plans will be given.
The Majorana Double Beta Decay Experiment: Present Status
Energy Technology Data Exchange (ETDEWEB)
Aguayo, Estanislao; Avignone, Frank T.; Back, Henning O.; Barabash, Alexander S.; Beene, Jim; Bergevin, M.; Bertrand, F.; Boswell, M.; Brudanin, V.; Busch, Matthew; Chan, Yuen-Dat; Christofferson, C. D.; Collar, J. I.; Combs, Dustin C.; Cooper, R. J.; Detwiler, Jason A.; Doe, Peter J.; Efremenko, Yuri; Egorov, Viatcheslav; Ejiri, H.; Elliott, S. R.; Esterline, James H.; Fast, James E.; Fields, N.; Finnerty, P.; Fraenkle, Florian; Gehman, Victor M.; Giovanetti, G. K.; Green, M. P.; Guiseppe, V. E.; Gusey, K.; Hallin, A. L.; Hazama, R.; Henning, Reyco; Hime, Andrew; Hoppe, Eric W.; Horton, Mark; Howard, Stanley; Howe, M. A.; Johnson, R. A.; Keeter, K.; Keller, C.; Kidd, M. F.; Knecht, A.; Kochetov, Oleg; Konovalov, S.; Kouzes, Richard T.; Laferriere, Brian D.; LaRoque, B. H.; Leon, Jonathan D.; Leviner, L.; Loach, J. C.; MacMullin, S.; Marino, Michael G.; Martin, R. D.; Mei, Dong-Ming; Merriman, Jason H.; Miller, M. L.; Mizouni, Leila; Nomachi, Masaharu; Orrell, John L.; Overman, Nicole R.; Phillips II, D. G.; Poon, Alan; Perumpilly, Gopakumar; Prior, Gersende; Radford, D. C.; Rielage, Keith; Robertson, R. G. H.; Ronquest, M. C.; Schubert, Alexis G.; Shima, T.; Shirchenko, M.; Snavely, Kyle J.; Steele, David; Strain, J.; Thomas, K.; Timkin, V.; Tornow, W.; Vanyushin, I.; Varner, R. L.; Vetter, Kai; Vorren, Kris R.; Wilkerson, J. F.; Yakushev, E.; Young, A.; Yu, Chang-Hong; Yumatov, Vladimir; Zhang, C.
2013-06-01
The Majorana collaboration is actively pursuing research and development aimed at a tonne-scale 76Ge neutrinoless double-beta decay experiment, an R&D effort that will field approximately 40 kg of germanium detectors with mixed enrichment levels. This article provides a status update on the construction of the Demonstrator
Grand unification and the double beta-decay
International Nuclear Information System (INIS)
Faessler, A.
1992-01-01
Models of the unification of the electroweak and the strong interaction predict that the neutrino is a Majorana particle and therefore essentially identical with its own antiparticle. In such grand unified models the neutrino has also a finite mass and a slight right-handed weak interaction, since the model is left-right symmetric. These models have also left handed and right-handed vector bosons to mediate the weak interactions. If these models are correct the neutrinoless double beta-decay is feasable. Thus if one finds the neutrinoless double beta-decay one knows that the standard model can not be correct in which the neutrino is a Dirac particle and therefore different from its antiparticle. Although the neutrinoless double beta-decay has not been seen it is possible to extract from the lower limits of the lifetime against the double neutrinoless beta-decay upper limits for the effective electron-neutrino mass and for the effective mixing angle of the right-handed and the left-handed vector bosons mediating the weak interaction. One also can obtain an effective upper limit for the mass ratio of the light and the heavy vector bosons. The extraction of this physical quantities from the data is made difficult due to the fact that the weak interaction must not be diagonal in the representation of the mass matrix of the six neutrinos requested by such left-right symmetric models. (author)
Directory of Open Access Journals (Sweden)
A. A. Kurteva
2016-08-01
Full Text Available Beta-decay of the nucleus 125I and spectroscopic characteristics of the daughter nucleus are described within the framework of the dynamic collective model. Quasiparticle and multiphonon states, as well as vacuum fluctuations of quasiparticles are taken into account. The comparison of the results of calculations with the available experimental data is performed.
Evaluation of beta-decay III. The complex gamma function
International Nuclear Information System (INIS)
Wilkinson, D.H.
1993-05-01
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
Time reversal violation in radiative beta decay: experimental plans
Behr, J. A.; McNeil, J.; Anholm, M.; Gorelov, A.; Melconian, D.; Ashery, D.
2017-01-01
Some explanations for the excess of matter over antimatter in the universe involve sources of time reversal violation (TRV) in addition to the one known in the standard model of particle physics. We plan to search for TRV in a correlation between the momenta of the beta, neutrino, and the radiative gamma sometimes emitted in nuclear beta decay. Correlations involving three (out of four) momenta are sensitive at lowest order to different TRV physics than observables involving spin, such as electric dipole moments and spin-polarized beta decay correlations. Such experiments have been done in radiative kaon decay, but not in systems involving the lightest generation of quarks. An explicit low-energy physics model being tested produces TRV effects in the Fermi beta decay of the neutron, tritium, or some positron-decaying isotopes. We will present plans to measure the TRV asymmetry in radiative beta decay of laser-trapped 38mK at better than 0.01 sensitivity, including suppression of background from positron annihilation. Supported by NSERC, D.O.E., Israel Science Foundation. TRIUMF receives federal funding via a contribution agreement with the National Research Council of Canada.
Computer code for double beta decay QRPA based calculations
Energy Technology Data Exchange (ETDEWEB)
Barbero, C. A.; Mariano, A. [Departamento de Física, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina and Instituto de Física La Plata, CONICET, La Plata (Argentina); Krmpotić, F. [Instituto de Física La Plata, CONICET, La Plata, Argentina and Instituto de Física Teórica, Universidade Estadual Paulista, São Paulo (Brazil); Samana, A. R.; Ferreira, V. dos Santos [Departamento de Ciências Exatas e Tecnológicas, Universidade Estadual de Santa Cruz, BA (Brazil); Bertulani, C. A. [Department of Physics, Texas A and M University-Commerce, Commerce, TX (United States)
2014-11-11
The computer code developed by our group some years ago for the evaluation of nuclear matrix elements, within the QRPA and PQRPA nuclear structure models, involved in neutrino-nucleus reactions, muon capture and β{sup ±} processes, is extended to include also the nuclear double beta decay.
Majorana neutrino masses and the neutrinoless double-beta decay
International Nuclear Information System (INIS)
Faessler, A.
2006-01-01
Neutrinoless double-beta decay is forbidden in the Standard Model of electroweak and strong interaction but allowed in most Grand Unified Theories (GUTs). Only if the neutrino is a Majorana particle (identical with its antiparticle) and if it has a mass is neutrinoless double-beta decay allowed. Apart from one claim that the neutrinoless double-beta decay in 76 Ge is measured, one has only upper limits for this transition probability. But even the upper limits allow one to give upper limits for the electron Majorana neutrino mass and upper limits for parameters of GUTs and the minimal R-parity-violating supersymmetric model. One further can give lower limits for the vector boson mediating mainly the right-handed weak interaction and the heavy mainly right-handed Majorana neutrino in left-right symmetric GUTs. For that, one has to assume that the specific mechanism is the leading one for neutrinoless double-beta decay and one has to be able to calculate reliably the corresponding nuclear matrix elements. In the present work, one discusses the accuracy of the present status of calculating of the nuclear matrix elements and the corresponding limits of GUTs and supersymmetric parameters
The majorana {sup 76}Ge double-beta decay project
Energy Technology Data Exchange (ETDEWEB)
Aalseth, C.E.; Adles, E.; Anderson, D.; Avignone, F.T.; Barabash, A.; Bowyer, T.W.; Brodzinski, R.L.; Brudanin, V.; Champangne, A.; Collar, J.I.; Doe, P.J.; Egorov, S.; Elliott, S.R.; Farach, H.A.; Gaitskell, R.; Jordan, D.; Jain, R.K.; Kazkaz, K.; King, G.; Kochetov, O.; Konovalov, S.; Kouzes, R.; Miley, H.S.; Palms, J.M.; Pitts, W.K.; Reeves, J.H.; Robertson, R.G.H.; Rohm, R.; Sandukovsky, S.; Smith, L.E.; Stekhanov, V.; Thompson, R.C.; Tornow, W.; Umatov' , V.; Warner, R.; Webb, J.; Wilkerson, J.F.; Young, A
2003-07-01
The interest and relevance of next-generation 0{sub v} {beta}{beta}-decay experiments is increasing. Even with nonzero neutrino mass strongly suggested by solar and atmospheric neutrino experiments sensitive to {delta}m{sup 2}, 0{sub v} {beta}{beta}-decay experiments are still the only way to establish the Dirac or Majorana nature of neutrinos by measuring the effective electron neutrino mass,
Spectrum of gluino bound states
International Nuclear Information System (INIS)
Chanowitz, M.; Sharpe, S.; California Univ., Berkeley
1983-01-01
Using the bag model to first order in αsub(s) we find that if light gluinos exist they will appear as constituents of electrically charged bound states which are stable against strong interaction decay. We review the present experimental constraints and conclude that light, long-lived charged hadrons containing gluinos might exist with lifetimes between 2x10 - 8 and 10 - 14 s. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Dokania, N.; Nanal, V.; Gupta, G.; Pillay, R.G.; Ghosh, C. [Tata Institute of Fundamental Research, Department of Nuclear and Atomic Physics, Mumbai (India); Pal, S. [Tata Institute of Fundamental Research, Pelletron Linac Facility, Mumbai (India); Rath, P.K. [University of Lucknow, Department of Physics, Lucknow (India); Tretyak, V.I. [Institute for Nuclear Research, Kyiv (Ukraine); Garai, A.; Krishnamoorthy, H. [Tata Institute of Fundamental Research, India-based Neutrino Observatory, Mumbai (India); Homi Bhabha National Institute, Mumbai (India); Raina, P.K. [Indian Institute of Technology, Department of Physics, Rupnagar (India); Bhushan, K.G. [Bhabha Atomic Research Centre, Technical Physics Division, Mumbai (India)
2017-04-15
Neutrinoless double beta decay is a phenomenon of fundamental interest in particle physics. The decay rates of double beta decay transitions to the excited states can provide input for Nuclear Transition Matrix Element calculations for the relevant two neutrino double beta decay process. It can be useful as supplementary information for the calculation of Nuclear Transition Matrix Element for the neutrinoless double beta decay process. In the present work, double beta decay of {sup 94}Zr to the 2{sup +}{sub 1} excited state of {sup 94}Mo at 871.1 keV is studied using a low background ∝ 230 cm{sup 3} HPGe detector. No evidence of this decay was found with a 232 g.y exposure of natural zirconium. The lower half-life limit obtained for the double beta decay of {sup 94}Zr to the 2{sup +}{sub 1} excited state of {sup 94}Mo is T{sub 1/2}(0ν + 2ν) > 3.4 x 10{sup 19} y at 90% C.L., an improvement by a factor of ∝ 4 over the existing experimental limit at 90% C.L. The sensitivity is estimated to be T{sub 1/2} (0ν + 2ν) > 2.0 x 10{sup 19} y at 90% C.L. using the Feldman-Cousins method. (orig.)
Extra dimensions and neutrinoless double beta decay experiments
International Nuclear Information System (INIS)
Gozdz, Marek; Kaminski, Wieslaw A.; Faessler, Amand
2005-01-01
The neutrinoless double beta decay is one of the few phenomena, belonging to the nonstandard physics, which is extensively being sought for in experiments. In the present paper the link between the half-life of the neutrinoless double beta decay and theories with large extra dimensions is explored. The use of the sensitivities of currently planned 0ν2β experiments: DAMA, CANDLES, COBRA, DCBA, CAMEO, GENIUS, GEM, MAJORANA, MOON, CUORE, EXO, and XMASS, gives the possibility for a nondirect 'experimental' verification of various extra dimensional scenarios. We discuss also the results of the Heidelberg-Moscow Collaboration. The calculations are based on the Majorana neutrino mass generation mechanism in the Arkani-Hamed-Dimopoulos-Dvali model
Precision study of the $\\beta$-decay of $^{74}$Rb
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.
Searches for massive neutrinos in nuclear beta decay
International Nuclear Information System (INIS)
Jaros, J.A.
1992-10-01
The status of searches for massive neutrinos in nuclear beta decay is reviewed. The claim by an ITEP group that the electron antineutrino mass > 17eV has been disputed by all the subsequent experiments. Current measurements of the tritium beta spectrum limit m bar νe < 10 eV. The status of the 17 keV neutrino is reviewed. The strong null results from INS Tokyo and Argonne, and deficiencies in the experiments which reported positive effects, make it unreasonable to ascribe the spectral distortions seen by Simpson, Hime, and others to a 17keV neutrino. Several new ideas on how to search for massive neutrinos in nuclear beta decay are discussed
Precision Study of the $\\beta$-decay of $^{62}$Ga
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.
$\\beta$-decay studies using total-absorption spectroscopy
Algora, A; García-Borge, M J; Cano-Ott, D; Collatz, R; Courtin, S; Dessagne, P; Fraile-Prieto, L M; Gadea, A; Gelletly, W; Hellström, M; Janas, Z; Jungclaus, A; Kirchner, R; Karny, M; Le Scornet, G; Miehé, C; Maréchal, F; Moroz, F; Nacher, E; Poirier, E; Roeckl, E; Rubio, B; Rykaczewski, K; Taín, J L; Tengblad, O; Wittmann, V
2004-01-01
$\\beta$-decay experiments are a primary source of information for nuclear-structure studies and at the same time complementary to in- beam investigations of nuclei far from stability. Although both types of experiment are mainly based on $\\gamma$-ray spectroscopy, they face different experimental problems. The so-called " Pandemonium effect " is a critical problem in $\\beta$-decay if we are to test theoretically calculated transition probabilities. In this contribution we will present a solution to this problem using total absorption spectroscopy methods. We will also present some examples of experiments carried out with the Total Absorption Spectrometer (TAS) at GSI and describe a new device LUCRECIA recently installed at CERN.
Search for neutrinoless double beta decay beyond GERDA
Energy Technology Data Exchange (ETDEWEB)
Schwingenheuer, Bernhard [MPI Kernphysik, Heidelberg (Germany)
2016-07-01
The search for neutrinoless double beta decay might be the only window to observe lepton number violation and to determine the nature of neutrinos. Is is therefore considered to be of highest relevance. The isotope Ge-76 has historically been most important for this search and the ongoing experiment GERDA has the lowest background of all experiments in the field. The proposed experimental program beyond GERDA (and Majorana) is presented.
The Majorana Double Beta Decay Experiment:. Present Status
Aguayo, E.; Avignone, F. T.; Back, H. O.; Barabash, A. S.; Beene, J. R.; Bergevin, M.; Bertrand, F. E.; Boswell, M.; Brudanin, V.; Busch, M.; Chan, Y.-D.; Christofferson, C. D.; Collar, J. I.; Combs, D. C.; Cooper, R. J.; Detwiler, J. A.; Doe, P. J.; Efremenko, Yu.; Egorov, V.; Ejiri, H.; Elliott, S. R.; Esterline, J.; Fast, J. E.; Fields, N.; Finnerty, P.; Fraenkle, F. M.; Gehman, V. M.; Giovanetti, G. K.; Green, M. P.; Guiseppe, V. E.; Gusey, K.; Hallin, A. L.; Hazama, R.; Henning, R.; Hime, A.; Hoppe, E. W.; Horton, M.; Howard, S.; Howe, M. A.; Johnson, R. A.; Keeter, K. J.; Keller, C.; Kidd, M. F.; Knecht, A.; Kochetov, O.; Konovalov, S. I.; Kouzes, R. T.; Laferriere, B. D.; Laroque, B. H.; Leon, J.; Leviner, L. E.; Loach, J. C.; Macmullin, S.; Marino, M. G.; Martin, R. D.; Mei, D.-M.; Merriman, J. H.; Miller, M. L.; Mizouni, L.; Nomachi, M.; Orrell, J. L.; Overman, N. R.; Phillips, D. G.; Poon, A. W. P.; Perumpilly, G.; Prior, G.; Radford, D. C.; Rielage, K.; Robertson, R. G. H.; Ronquest, M. C.; Schubert, A. G.; Shima, T.; Shirchenko, M.; Snavely, K. J.; Steele, D.; Strain, J.; Thomas, K.; Timkin, V.; Tornow, W.; Vanyushin, I.; Varner, R. L.; Vetter, K.; Vorren, K.; Wilkerson, J. F.; Yakushev, E.; Young, A. R.; Yu, C.-H.; Yumatov, V. I.; Zhang, C.
2013-11-01
The Majorana collaboration is actively pursuing research and development aimed at a tonne-scale 76Ge neutrinoless double-beta decay (0νββ) experiment. The current, primary focus is the construction of the Majorana Demonstrator experiment, an R&D effort that will field approximately 40 kg of germanium detectors with mixed enrichment levels. This article provides a status update on the construction of the Demonstrator.
Beta-decay studies at the N=28 shell closure
Czech Academy of Sciences Publication Activity Database
Grévy, S.; Mrázek, Jaromír; Angelique, J. C.; Baumann, P.; Borcea, C.; Buta, A.; Canchel, G.; Cargord, W.; Courtin, S.; Daugas, J. M.; de Oliveira Santos, F.; Dlouhý, Zdeněk; Knipper, A.; Kratz, K. L.; Lecouey, J. L.; Lecolley, F. R.; Lehrsenneau, G.; Lewitowicz, M.; Lienard, E.; Lukianov, S.; Marechal, F.; Miehe, C.; Negoita, F.; Orr, NA.; Pantelica, D.; Penionzhkevich, Y. E.; Peter, J.; Pfeiffer, B.; Pietri, S.; Poirier, E.; Sorlin, O.; Stanoiu, M.; Stodel, C.; Timis, C.
2003-01-01
Roč. 722, - (2003), s. 424C-428C ISSN 0375-9474 R&D Projects: GA AV ČR IAA1048605; GA AV ČR KSK1048102 Institutional research plan: CEZ:AV0Z1048901 Keywords : beta-decay spectroscopy * beta half-lives Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.761, year: 2003
Neutrinoless double beta decay searches with 76Ge
CERN. Geneva
2017-01-01
The search for neutrinoless double beta decay might be the only window to observe lepton number violation. Its observation would favour the leptogenesis mechanism for the explanation of the baryon asymmetry of the universe and is therefore considered to be of highest relevance. The isotope 76Ge has historically been most important for this search and the ongoing experiment GERDA has the lowest background of all experiments in the field. The talk reviews the motivation, the current status of experiments and future programs.
The Standard Model and the neutron beta-decay
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.
Inner bremsstrahlung accompanying beta decay of 170Tm
International Nuclear Information System (INIS)
Sanjeeviah, H.; Venkataramaiah, P.; Gundu Rao, K.S.
1980-01-01
The inner bremmsstrahlung (IB) spectrum accompanying beta decay of 170 Tm was measured using magnetic deflection technique. The raw spectrum was unfolded using the procedure of Liden and Starfelt. The unfolded IB spectrum was compared with the theories of Knipp and Uhlenbeck and Bloch; Lewis and Ford. Comparison was made with Ford and Martin theory in order to estimate the contribution of detour transitions to the IB spectrum of 170 Tm. (author)
Relativistic bound state wave functions
International Nuclear Information System (INIS)
Micu, L.
2005-01-01
A particular method of writing the bound state wave functions in relativistic form is applied to the solutions of the Dirac equation with confining potentials in order to obtain a relativistic description of a quark antiquark bound system representing a given meson. Concerning the role of the effective constituent in the present approach we first observe that without this additional constituent we couldn't expand the bound state wave function in terms of products of free states. Indeed, we notice that if the wave function depends on the relative coordinates only, all the expansion coefficients would be infinite. Secondly we remark that the effective constituent enabled us to give a Lorentz covariant meaning to the potential energy of the bound system which is now seen as the 4th component of a 4-momentum. On the other side, by relating the effective constituent to the quantum fluctuations of the background field which generate the binding, we provided a justification for the existence of some spatial degrees of freedom accompanying the interaction potential. These ones, which are quite unusual in quantum mechanics, in our model are the natural consequence of the the independence of the quarks and can be seen as the effect of the imperfect cancellation of the vector momenta during the quantum fluctuations. Related with all these we remark that the adequate representation for the relativistic description of a bound system is the momentum representation, because of the transparent and easy way of writing the conservation laws and the transformation properties of the wave functions. The only condition to be fulfilled is to find a suitable way to take into account the potential energy of the bound system. A particular feature of the present approach is that the confining forces are due to a kind of glue where both quarks are embedded. This recalls other bound state models where the wave function is factorized in terms of constituent wave functions and the confinement is
New Limit on Time-Reversal Violation in Beta Decay
International Nuclear Information System (INIS)
Mumm, H. P.; Chupp, T. E.; Cooper, R. L.; Coulter, K. P.; Freedman, S. J.; Fujikawa, B. K.; Garcia, A.; Jones, G. L.; Nico, J. S.; Thompson, A. K.; Trull, C. A.; Wietfeldt, F. E.; Wilkerson, J. F.
2011-01-01
We report the results of an improved determination of the triple correlation DP·(p e xp v ) that can be used to limit possible time-reversal invariance in the beta decay of polarized neutrons and constrain extensions to the standard model. Our result is D=[-0.96±1.89(stat)±1.01(sys)]x10 -4 . The corresponding phase between g A and g V is φ AV =180.013 deg. ±0.028 deg. (68% confidence level). This result represents the most sensitive measurement of D in nuclear β decay.
Proposed experimental test of Bell's inequality in nuclear beta decay
International Nuclear Information System (INIS)
Skalsey, M.
1986-01-01
A β decay experiment is proposed for testing Bell's inequality, related to hidden-variables alternatives to quantum mechanics. The experiment uses Mott scattering for spin polarization analysis of internal conversion electrons. Beta-decay electrons, in cascade with the conversion electrons, are longitudinally polarized due to parity violation in the weak interaction. So simply detecting the β electron direction effectively measures the spin. A two-particle spin-spin correlation can thus be investigated and related, within certain assumptions, to Bell's inequality. The example of 203 Hg decay is used for a calculation of expected results. Specific problems related to nuclear structure and experimental inconsistencies are also discussed
Project for detecting the double beta decay of 136Xe
International Nuclear Information System (INIS)
Miyajima, M.; Sasaki, S.; Tawara, H.
1992-01-01
For detecting the nuclear double beta decay of 136 Xe, a liquid-xenon positive-ion collector and a time-of-flight mass spectrometer are under development for detecting the decay product 136 Ba. Two sets of lasers are used with the mass spectrometer. An Nd-YAG laser is used for sampling 136 Ba from the surface of the positive-ion collector electrode, and a dye laser pumped by an Nd-YAG laser is used for the selective ionization of 136 Ba. The principle of measurements as well as the experimental apparatus and procedures are described in detail, together with our future plans. (orig.)
Study of the ${\\beta}$-decay of $^{12}$B
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.
Double beta decay in the generalized seniority scheme
International Nuclear Information System (INIS)
Pittel, S.; Engel, J.; Vogel, P.; Ji Xiangdong
1990-01-01
A generalized-seniority truncation scheme is used in shell-model calculations of double beta decay matrix elements. Calculations are carried out for 78 Ge, 82 Se and 128,130 Te. Matrix elements calculated for the two-neutrino decay mode are small compared to weak-coupling shell-model calculations and support the suppression mechanism first observed in the quasi-particle random phase approximation. Matrix elements for the neutrinoless mode are similar to those of the weak-coupling shell model, suggesting that these matrix elements can be pinned down fairly accurately. (orig.)
Gamow-Teller beta decay of proton-rich nuclei
International Nuclear Information System (INIS)
Klepper, O.; Rykaczewski, K.
1990-11-01
The beta decays of 48 Mn and of even-even nuclei near the double shell-closures at 100 Sn and 146 Gd are currently investigated at the GSI on-line mass separator. Their Gamow-Teller strength are surveyed in their present experimental status, together with related results from the ISOLDE (CERN) and ISOCELE (Orsay) separators, and are compared with predictions from different nuclear models. The strength of the 0 + → 1 + Gamow-Teller transitions is compiled in tables and graphs. (orig.)
Schematic model studies of double beta decay processes
International Nuclear Information System (INIS)
Civitarese, O.
1996-01-01
Some features of the nuclear matrix elements, for double beta decay transitions to a final ground state and to a final excited one and two-quadrupole phonon states, are presented and discussed in the framework of a schematic model. The competition between spin-flip and non-spin-flip transitions on the relevant nuclear matrix elements, the effects due to proton-neutron pairing correlations and the effects due to the inclusion of exchange terms in the QRPA matrix are discussed. (Author)
Experimental search for double beta decay of 100Mo
International Nuclear Information System (INIS)
Alston-Garnjost, M.; Dougherty, B.L.; Kenney, R.W.; Krivicich, J.M.; Tripp, R.D.; Nicholson, H.W.; Dieterle, B.D.; Leavitt, C.P.
1986-01-01
An experiment is proposed to search for double beta decay in 100 Mo using thin silicon solid state detectors. We expect to be sensitive to a half life limit of over 2 x 10 23 years for the neutrinoless mode and 2 x 10 20 years for the two-neutrino mode in one year's running. This is a substantial improvement in the measurement of the limits on electron neutrino mass and/or right-handed current admixtures over present 76 Ge experiments. 16 refs., 12 figs., 9 tabs
Instanton bound states in ABJM theory
Energy Technology Data Exchange (ETDEWEB)
Hatsuda, Yasuyuki [DESY Hamburg (Germany). Theory Group; Tokyo Institute of Technology (Japan). Dept. of Physics; Moriyama, Sanefumi [Nagoya Univ. (Japan). Kobayashi Maskawa Inst. and Graduate School of Mathematics; Okuyama, Kazumi [Shinshu Univ., Matsumoto, Nagano (Japan). Dept. of Physics
2013-06-15
The partition function of the ABJM theory receives non-perturbative corrections due to instanton effects. We study these non-perturbative corrections, including bound states of worldsheet instantons and membrane instantons, in the Fermi-gas approach. We require that the total non-perturbative correction should be always finite for arbitrary Chern-Simons level. This finiteness is realized quite non-trivially because each bound state contribution naively diverges at some levels. The poles of each contribution should be canceled out in total. We use this pole cancellation mechanism to find unknown bound state corrections from known ones. We conjecture a general expression of the bound state contribution. Summing up all the bound state contributions, we find that the effect of bound states is simply incorporated into the worldsheet instanton correction by a redefinition of the chemical potential in the Fermi-gas system. Analytic expressions of the 3- and 4-membrane instanton corrections are also proposed.
Measurement of Radon-Induced Backgrounds in the NEXT Double Beta Decay Experiment
Energy Technology Data Exchange (ETDEWEB)
Novella, P.; et al.
2018-04-02
The measurement of the internal 222Rn activity in the NEXT-White detector during the so-called Run-II period with 136Xe-depleted xenon is discussed in detail, together with its implications for double beta decay searches in NEXT. The activity is measured through the alpha production rate induced in the fiducial volume by 222Rn and its alpha-emitting progeny. The specific activity is measured to be $(37.5\\pm 2.3~\\mathrm{(stat.)}\\pm 5.9~\\mathrm{(syst.)})$~mBq/m$^3$. Radon-induced electrons have also been characterized from the decay of the 214Bi daughter ions plating out on the cathode of the time projection chamber. From our studies, we conclude that radon-induced backgrounds are sufficiently low to enable a successful NEXT-100 physics program, as the projected rate contribution should not exceed 0.2~counts/yr in the neutrinoless double beta decay sample.
The contribution of electron capture to weak-decay rates has been neglected in model calculations of Type I X-ray bursts so far. Nucleosynthesis in these astrophysical events eventually proceeds through the rp-process near the proton drip-line. In particular, several N=Z nuclei such as $^{64}$Ge and $^{68}$Se act as waiting points in the nuclear flow due to the low S${_P}$ values of their Z+1 neighbours. Recent theoretical calculations have shown that, in these high density ($\\thicksim10^{6}$ g/cm$^3$) and high temperature (1 - 2 GK) scenarios, continuum electron capture rates might play an important role, in particular for species at and around these waiting point nuclei. This proposal is aimed at the study of the $\\beta^{+}$/EC-decay of the waiting point nuclei $^{64}$Ge, $^{68}$Se and their N=Z+2 second neighbours $^{66}$Ge and $^{70}$Se with the Total Absorption Spectroscopy method. This will allow for a detailed analysis of their contribution to the EC-decay rates in X-Ray burst explosions. The proposed ...
PandaX-III neutrinoless double beta decay experiment
Wang, Shaobo; PandaX-III Collaboration
2017-09-01
The PandaX-III experiment uses high pressure Time Projection Chambers (TPCs) to search for neutrinoless double-beta decay of Xe-136 with high energy resolution and sensitivity at the China Jin-Ping underground Laboratory II (CJPL-II). Fine-pitch Microbulk Micromegas will be used for charge amplification and readout in order to reconstruct both the energy and track of the neutrinoless double-beta decay event. In the first phase of the experiment, the detector, which contains 200 kg of 90% Xe-136 enriched gas operated at 10 bar, will be immersed in a large water tank to ensure 5 m of water shielding. For the second phase, a ton-scale experiment with multiple TPCs will be constructed to improve the detection probability and sensitivity. A 20-kg scale prototype TPC with 7 Micromegas modules has been built to optimize the design of Micromegas readout module, study the energy calibration of TPC and develop algorithm of 3D track reconstruction.
On the Proton Spectrum in Free Neutron beta-decay
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...
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
Hyperquarks and bosonic preon bound states
International Nuclear Information System (INIS)
Schmid, Michael L.; Buchmann, Alfons J.
2009-01-01
In a model in which leptons, quarks, and the recently introduced hyperquarks are built up from two fundamental spin-(1/2) preons, the standard model weak gauge bosons emerge as preon bound states. In addition, the model predicts a host of new composite gauge bosons, in particular, those responsible for hyperquark and proton decay. Their presence entails a left-right symmetric extension of the standard model weak interactions and a scheme for a partial and grand unification of nongravitational interactions based on, respectively, the effective gauge groups SU(6) P and SU(9) G . This leads to a prediction of the Weinberg angle at low energies in good agreement with experiment. Furthermore, using evolution equations for the effective coupling strengths, we calculate the partial and grand unification scales, the hyperquark mass scale, as well as the mass and decay rate of the lightest hyperhadron.
Neutrinoless double-beta decay - Status of evidence and future
International Nuclear Information System (INIS)
Klapdor-Kleingrothaus, H.V.
2002-01-01
Double-beta decay is indispensable to solve the question of the neutrino mass matrix together with ν oscillation experiments. Recent analysis of the most sensitive experiment in the last eight years - the Heidelberg-Moscow experiment in Gran Sasso - yields evidence for the neutrinoless decay mode at a 97% C.L. This result is the first indication for lepton number violation and for the neutrino to be a Majorana particle. We give the present status of the analysis in these proceedings. It excludes several of the neutrino mass scenarios allowed from present neutrino oscillation experiments - essentially only degenerate and partially degenerate mass scenarios survive. To improve the present result, considerably enlarged experiments are required, such as GENIUS. A GENIUS Test Facility has just been funded and will come into operation by the end of 2002
Progress report on the Los Alamos tritium beta decay experiment
International Nuclear Information System (INIS)
Wilkerson, J.F.; Bowles, T.J.; Knapp, D.A.; Robertson, R.G.H.; Wark, D.L.
1988-01-01
Measurements near the endpoint of the tritium beta-decay spectrum using a gaseous molecular tritium source yield an essentially model-independent upper limit of 27 eV on the /ovr ν//sub e/ mass at the 95% confidence level. Since demonstrating from this initial measurement the successful operation of a gaseous source based system, most of our effort has been concentrated towards the upgrade and optimization of the experimental apparatus. The emphasis of this work has been to eliminate or further reduce effects that generate systematic errors. Based on realistic projections from our initial measurement, an ultimate sensitivity to neutrino mass of 10 eV is expected. 12 refs., 1 fig
An experimental investigation of double beta decay of 100Mo
International Nuclear Information System (INIS)
Dougherty, B.L.
1988-01-01
New limits on half-lives for several double beta decay modes of 100 Mo were obtained with a novel experimental system which included thin source films interleaved with a coaxial array of windowless silicon detectors. Segmentation and timing information allowed backgrounds originating in the films to be studied in some detail. Dummy films containing 96 Mo were used to assess remaining backgrounds. With 0.1 mole years of 100 Mo data collected, the lower half-life limits at 90% confidence were 2.7 /times/ 10 18 years for decay via the two-neutrino mode, 5.2 /times/10 19 years for decay with the emission of a Majoron, and 1.6 /times/ 10 20 years and 2.2 /times/ 10 21 years for neutrinoless 0 + → 2 + and 0 + → 0 + transitions, respectively. 50 refs., 38 figs., 11 tabs
The beta decay asymmetry parameter of 35Ar
International Nuclear Information System (INIS)
Garnett, J.D.
1987-11-01
The beta decay asymmetry parameter for 35 Ar = 35 Cl + e + + nu/sub e/ has been remeasured in order to resolve a long standing puzzle. Previous asymmetry measurements, when combined with the comparative half-life, yield a value for the vector coupling constant, G/sub v/, that is in serious disagreement with the accepted value. We produced polarized 35 Ar by a (p,n) reaction on 35 Cl using the polarized proton beam provided by Lawrence Berkeley Laboratory's 88-Inch Cyclotron. The polarization of the 35 Ar was determined by measuring the asymmetry of the positrons produced in 35 Ar decay to the first excited state in 35 Cl (branching ratio = 1.3%) in coincidence with a 1219.4 keV gamma ray. Our result, A 0 = 0.49 +- 0.10, combined with the comparative half-life yields a value for G/sub v/ in agreement with the accepted value
Beta decay of 31,32Na and 31Mg
International Nuclear Information System (INIS)
Klotz, G.; Baumann, P.; Bounajma, M.; Huck, A.; Knipper, A.; Walter, G.; Poves, A.; Retamosa, J.
1993-01-01
31,32 Na and 31 Mg beta decays were studied at the CERN on-line mass separator ISOLDE by gamma, gamma-gamma and neutron-gamma measurements. In the 31 Na decay, the assignment of previously reported γ transitions and the observation of a new level at 3760 keV lead to a revised decay scheme. In the 31 Mg → 31 Al decay, a new decay scheme involves ten β branches and three states are reported for the first time. New spectroscopic results have been obtained in the 32 Na β - decay. A previously non-interpreted 1436 keV γ ray is now assigned in the 32 Mg scheme. (author) 33 refs., 16 figs., 12 tabs
Effects of QCD bound states on dark matter relic abundance
Energy Technology Data Exchange (ETDEWEB)
Liew, Seng Pei [Department of Physics, The University of Tokyo,Bunkyo-ku, Tokyo 113-0033 (Japan); Luo, Feng [Kavli IPMU (WPI), UTIAS, The University of Tokyo,Kashiwa, Chiba 277-8583 (Japan)
2017-02-17
We study scenarios where there exists an exotic massive particle charged under QCD in the early Universe. We calculate the formation and dissociation rates of bound states formed by pairs of these particles, and apply the results in dark matter (DM) coannihilation scenarios, including also the Sommerfeld effect. We find that on top of the Sommerfeld enhancement, bound-state effects can further significantly increase the largest possible DM masses which can give the observed DM relic abundance, by ∼30–100% with respect to values obtained by considering the Sommerfeld effect only, for the color triplet or octet exotic particles we consider. In particular, it indicates that the Bino DM mass in the right-handed stop-Bino coannihilation scenario in the Minimal Supersymmetric extension of the Standard Model (MSSM) can reach ∼2.5 TeV, even though the potential between the stop and antistop prior to forming a bound state is repulsive. We also apply the bound-state effects in the calculations of relic abundance of long-lived or metastable massive colored particles, and discuss the implications on the BBN constraints and the abundance of a super-weakly interacting DM. The corrections for the bound-state effect when the exotic massive colored particles also carry electric charges, and the collider bounds are also discussed.
Main features of detectors and isotopes to investigate double beta decay with increased sensitivity
Barabash, A. S.
2018-03-01
The current situation in double beta decay experiments, the characteristics of modern detectors and the possibility of increasing the sensitivity to neutrino mass in future experiments are discussed. The issue of the production and use of enriched isotopes in double beta decay experiments is discussed in addition.
The empirical connection between (p,n) cross sections and beta decay transition strengths
International Nuclear Information System (INIS)
Taddeucci, T.N.
1988-01-01
A proportionality is assumed to exist between 0/degree/ (p,n) cross sections and the corresponding beta decay transition strengths. The validity of this assumption is tested by comparison of measured (p,n) cross sections and analogous beta decay strengths. Distorted waves impulse approximation calculations also provide useful estimates of the accuracy of the proportionality relationship. 14 refs., 10 figs
The bound state problem and quark confinement
International Nuclear Information System (INIS)
Chaichian, M.; Demichev, A.P.; Nelipa, N.F.
1980-01-01
A quantum field-theoretic model in which quark is confined is considered. System of equations for the Green functions of colour singlet and octet bound states is obtained. The method is based on the nonperturbative Schwinger-Dyson equations with the use of Slavnov-Taylor identities. It is shown that in the framework of the model if there exist singlet, then also exist octet bound states of the quark-antiquark system. Thus in general, confinement of free quarks does not mean absence of their coloured bound states. (author)
Quasi-bound states in continuum
International Nuclear Information System (INIS)
Nakamura, Hiroaki; Hatano, Naomichi; Garmon, Sterling; Petrosky, Tomio
2007-08-01
We report the prediction of quasi-bound states (resonant states with very long lifetimes) that occur in the eigenvalue continuum of propagating states for a wide region of parameter space. These quasi-bound states are generated in a quantum wire with two channels and an adatom, when the energy bands of the two channels overlap. A would-be bound state that lays just below the upper energy band is slightly destabilized by the lower energy band and thereby becomes a resonant state with a very long lifetime (a second QBIC lays above the lower energy band). (author)
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)
Evolution of single-particle structure and beta-decay near 78Ni
Directory of Open Access Journals (Sweden)
Borzov I. N.
2012-12-01
Full Text Available The extended self-consistent beta-decay model has been applied for bet-decay rates and delayed neutron emission probabilities of spherical neutron-rich isotopes near the r-process paths. Unlike a popular global FRDM+RPA model, in our fully microscopic approach, the Gamow-Teller and first-forbidden decays are treated on the same footing. The model has been augmented by blocking of the odd particle in order to account for important ground-state spin-parity inversion effect which has been shown to exist in the region of the most neutron-rich doubly-magic nucleus 78Ni. Finally, a newly developed form of density functional DF3a has been employed which gives a better spin-orbit splitting due to the modified tensor components of the density functional.
LUCIFER, a potentially background-free approach to the search for neutrinoless double beta decay
Energy Technology Data Exchange (ETDEWEB)
Nones, C. [Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse, Bat. 108 Orsay Campus - Orsay (France)
2011-08-15
LUCIFER (Low-background Underground Cryogenic Installation For Elusive Rates) is a new project for the study of neutrinoless Double Beta Decay, based on the technology of scintillating bolometers. These devices promise a very efficient rejection of the alpha background, opening the way to a virtual background-free experiment if candidates with a transition energy higher than 2615 keV are investigated. The baseline candidate for LUCIFER is {sup 82}Se. This isotope will be embedded in ZnSe crystals grown with enriched selenium and operated as scintillating bolometers in a low-radioactivity underground dilution refrigerator. In this paper, the LUCIFER concept will be introduced. The sensitivity and the very promising prospects related to this project will be discussed.
Double beta decay, neutrino physics, nuclear structure and isospin and spin-isospin symmetries
International Nuclear Information System (INIS)
Krmpotic, F.
1989-12-01
Prominent features of the double beta decay processes are reviewed. Emphasis is placed on the neutrino masses and the quasiparticle random phase approximation (GRPA). The suppression mechanism for the ββ-decay transition rates, proposed by Vogel and Zirnbauer, is found to be closely related to the restoration of SU(4) symmetry. It is suggested that the extreme sensitivity of the ββ-decay amplitude on the proton-neutron coupling is a consequence of the explicit violation of the SU(4) symmetry and therefore an artifact of the model. A prescription is given for fixing this interaction strength within the GRPA itself, which in this way acquires predicting power on both single and double β-decay lifetimes. (author) [pt
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 Ge^{76} with a total sensitive mass of ~30 kg. This will accomplish two goals. First, it will test not yet confirmed claim for observation of neutrino-less double beta decay. Second, it will establish that the selected technology is capable of extension to a one-ton experiment with sufficient sensitivity to measure neutrino mass m_{ββ} down to 10 meV. To achieve the last goal, collaboration must demonstrate that a background level of 1 count per year per 4 keV per ton of detector is achievable. The University of Tennessee (UT) neutrino group has made a major commitment to the MJD. P.I. accepted the responsibility for one of the major tasks of the experiment, “Materials and Assay Task” which is crucial to the achievement of low background levels required for the experiment. In addition, the UT group is committed to construct, commission, and operate the MJD active veto system. Those activities were supported by NP-DOE via program funding for “Search for the Neutrino Less Double Beta Decay” at the University
The Gerda search for neutrinoless double beta decay
O'Shaughnessy, Christopher; Gerda Collaboration
2013-10-01
The Germanium Detector Array (Gerda) is a search for the neutrinoless double beta decay of 76Ge. High Purity Germanium (HPGe) detectors enriched in the isotope-76 are operated bare in liquid argon (LAr). LAr is used for both cooling of the HPGe diodes to their operating temperatures and for shielding from external radiation sources. From the measurements of the first phase that began data taking on 1 Nov. 2011 it is expected to have a sensitivity on the level of T1/2>2E25 yr at a 90% CL after 15 kġyr. The goal of this phase will be to probe the claim of an observation by part of the Heidelberg-Moscow collaboration. Efforts will then focus on increasing the sensitivity of the experiment by deploying additional enriched detectors that are in an advanced stage of production and by reducing the background index further by making use of pulse shape discrimination techniques as well as an active LAr veto. While the 0νββ region of interest continues to remain blinded, here the status of Phase-I data taking is presented along with the work towards improving the experimental sensitivity.
Constraining neutrino mass from neutrinoless double beta decay
Dev, P. S. Bhupal; Goswami, Srubabati; Mitra, Manimala; Rodejohann, Werner
2013-11-01
We study the implications of the recent results on neutrinoless double beta decay (0νββ) from GERDA-I (Ge76) and KamLAND-Zen+EXO-200 (Xe136) and the upper limit on the sum of light neutrino masses from Planck. We show that the upper limits on the effective neutrino mass from Xe136 are stronger than those from Ge76 for most of the recent calculations of the nuclear matrix elements (NMEs). We also analyze the compatibility of these limits with the claimed observation in Ge76 and show that while the updated claim value is still compatible with the recent GERDA limit as well as the individual Xe136 limits for a few NME calculations, it is inconsistent with the combined Xe136 limit for all but one NME. Imposing the most stringent limit from Planck, we find that the canonical light neutrino contribution cannot saturate the current limit, irrespective of the NME uncertainties. Saturation can be reached by inclusion of the right-handed (RH) neutrino contributions in TeV-scale left-right symmetric models with type-II seesaw. This imposes a lower limit on the lightest neutrino mass. Using the 0νββ bounds, we also derive correlated constraints in the RH sector, complimentary to those from direct searches at the LHC.
Search of Neutrinoless Double Beta Decay with the GERDA Experiment
Agostini, M.; Allardt, M.; Bakalyarov, A. M.; Balata, M.; Barabanov, I.; Baudis, L.; Bauer, C.; Becerici-Schmidt, N.; Bellotti, E.; Belogurov, S.; Belyaev, S. T.; Benato, G.; Bettini, A.; Bezrukov, L.; Bode, T.; Borowicz, D.; Brudanin, V.; Brugnera, R.; Budjáš, D.; Caldwell, A.; Cattadori, C.; Chernogorov, A.; D'Andrea, V.; Demidova, E. V.; Domula, A.; Doroshkevich, E.; Egorov, V.; Falkenstein, R.; Fedorova, O.; Freund, K.; Frodyma, N.; Gangapshev, A.; Garfagnini, A.; Gooch, C.; Gotti, C.; Grabmayr, P.; Gurentsov, V.; Gusev, K.; Hampel, W.; Hegai, A.; Heisel, M.; Hemmer, S.; Heusser, G.; Hoffmann, W.; Hult, M.; Inzhechik, L. V.; Ioannucci, L.; Janicksó Csáthy, J.; Jochum, J.; Junker, M.; Kazalov, V.; Kihm, T.; Kirpichnikov, I. V.; Kirsch, A.; Klimenko, A.; Knöpfle, K. T.; Kochetov, O.; Kornoukhov, V. N.; Kuzminov, V. V.; Laubenstein, M.; Lazzaro, A.; Lebedev, V. I.; Lehnert, B.; Liao, H. Y.; Lindner, M.; Lippi, I.; Lubashevskiy, A.; Lubsandorzhiev, B.; Lutter, G.; Macolino, C.; Majorovits, B.; Maneschg, W.; Marissens, G.; Medinaceli, E.; Misiaszek, M.; Moseev, P.; Nemchenok, I.; Nisi, S.; Palioselitis, D.; Panas, K.; Pandola, L.; Pelczar, K.; Pessina, G.; Pullia, A.; Reissfelder, M.; Riboldi, S.; Rumyantseva, N.; Sada, C.; Salathe, M.; Schmitt, C.; Schneider, B.; Schreiner, J.; Schulz, O.; Schwingenheuer, B.; Schönert, S.; Seitz, H.; Selivalenko, O.; Shevchik, E.; Shirchenko, M.; Simgen, H.; Smolnikov, A.; Stanco, L.; Stepaniuk, M.; Strecker, H.; Ur, C. A.; Vanhoefer, L.; Vasenko, A. A.; Veresnikova, A.; von Sturm, K.; Wagner, V.; Walter, M.; Wegmann, A.; Wester, T.; Wiesinger, C.; Wilsenach, H.; Wojcik, M.; Yanovich, E.; Zavarise, P.; Zhitnikov, I.; Zhukov, S. V.; Zinatulina, D.; Zuber, K.; Zuzel, G.
2016-04-01
The GERDA (GERmanium Detector Array) is an experiment for the search of neutrinoless double beta decay (0 νββ) in 76Ge, located at Laboratori Nazionali del Gran Sasso of INFN (Italy). In the first phase of the experiment, a 90% confidence level (C.L.) sensitivity of 2.4 ṡ1025 yr on the 0 νββ decay half-life was achieved with a 21.6 kgṡyr exposure and an unprecedented background index in the region of interest of 10-2 counts/(keVṡkgṡyr). No excess of signal events was found, and an experimental lower limit on the half-life of 2.1 ṡ 1025 yr (90% C.L.) was established. Correspondingly, the limit on the effective Majorana neutrino mass is mee < 0.2- 0.4 eV, depending on the considered nuclear matrix element. The previous claim for evidence of a 0 νββ decay signal is strongly disfavored, and the field of research is open again.
Search for neutrinoless double beta decay with GERDA phase II
Agostini, M.; Bakalyarov, A. M.; Balata, M.; Barabanov, I.; Baudis, L.; Bauer, C.; Bellotti, E.; Belogurov, S.; Bettini, A.; Bezrukov, L.; Bode, T.; Borowicz, D.; Brudanin, V.; Brugnera, R.; Caldwell, A.; Cattadori, C.; Chernogorov, A.; D'Andrea, V.; Demidova, E. V.; Di Marco, N.; Domula, A.; Doroshkevich, E.; Egorov, V.; Falkenstein, R.; Gangapshev, A.; Garfagnini, A.; Gooch, C.; Grabmayr, P.; Gurentsov, V.; Gusev, K.; Hakenmüller, J.; Hegai, A.; Heisel, M.; Hemmer, S.; Hofmann, W.; Hult, M.; Inzhechik, L. V.; Csáthy, J. Janicskó; Jochum, J.; Junker, M.; Kazalov, V.; Kihm, T.; Kirpichnikov, I. V.; Kirsch, A.; Kish, A.; Klimenko, A.; Kneißl, R.; Knies, J.; Knöpfle, K. T.; Kochetov, O.; Kornoukhov, V. N.; Kuzminov, V. V.; Laubenstein, M.; Lazzaro, A.; Lebedev, V. I.; Liao, H. Y.; Lindner, M.; Lippi, I.; Lubashevskiy, A.; Lubsandorzhiev, B.; Lutter, G.; Majorovits, B.; Maneschg, W.; Marissens, G.; Miloradovic, M.; Mingazheva, R.; Misiaszek, M.; Moseev, P.; Nemchenok, I.; Panas, K.; Pandola, L.; Pelczar, K.; Pullia, A.; Ransom, C.; Reissfelder, M.; Riboldi, S.; Rumyantseva, N.; Sada, C.; Salamida, F.; Schmitt, C.; Schneider, B.; Schönert, S.; Schreiner, J.; Schulz, O.; Schütz, A.-K.; Schwingenheuer, B.; Seitz, H.; Selivanenko, O.; Shevchik, E.; Shirchenko, M.; Simgen, H.; Smolnikov, A.; Stanco, L.; Vanhoefer, L.; Vasenko, A. A.; Veresnikova, A.; von Sturm, K.; Wagner, V.; Wegmann, A.; Wester, T.; Wiesinger, C.; Wojcik, M.; Yanovich, E.; Zhitnikov, I.; Zhukov, S. V.; Zinatulina, D.; Zuber, K.; Zuzel, G.
2017-10-01
The GERmanium Detector Array (gerda) experiment, located at the Gran Sasso underground laboratory in Italy, is one of the leading experiments for the search of 0νββ decay. In Phase II of the experiment 35.6 kg of enriched germanium detectors are operated. The application of active background rejection methods, such as a liquid argon scintillation light read-out and pulse shape discrimination of germanium detector signals, allowed to reduce the background index to the intended level of 10-3 cts/(keV.kg.yr). In the first five month of data taking 10.8 kg yr of exposure were accumulated. No signal has been found and together with data from Phase I a new limit for the neutrinoless double beta decay half-life of 76Ge of 5.3 . 1025 yr at 90% C.L. was established in June 2016. Phase II data taking is ongoing and will allow the exploration of half-lifes in the 1026 yr regime. The current status of data taking and an update on the background index are presented.
The CUORE neutrinoless double-beta decay experiment
International Nuclear Information System (INIS)
Banks, T.I.
2014-01-01
CUORE is an upcoming experiment designed to search for neutrinoless double-beta decay (0νββ) decay in 130 Te. Observation of the process would be a major finding because it would unambiguously establish that neutrinos are Majorana particles (i.e., their own antiparticles) as well as provide information about the absolute neutrino mass scale. The CUORE detector will consist of 988 identical TeO 2 crystal bolometers (containing 206 kg of 130 Te in total) arranged into 19 towers and cooled to about 10 mK at the underground Gran Sasso National Laboratory (LNGS), Italy, which provides the low-background environment necessary for rare event searches of this kind. A predecessor experiment, Cuoricino, ran from 2003-2008 at LNGS and served as a learning ground for CUORE, which will be 20 times larger and exhibit much lower backgrounds. The CUORE detector assembly line has produced its first tower, designated CUORE-0, which is expected to come online in the former Cuoricino cryostat in October 2012 and take data for about 2 years while 19 CUORE towers are assembled. CUORE data taking is expected for 2015-2019. (author)
Localizability of tachyonic particles and neutrinoless double beta decay
Energy Technology Data Exchange (ETDEWEB)
Jentschura, U.D. [Missouri University of Science and Technology, Department of Physics, Rolla, MO (United States); Institut fuer Theoretische Physik, Heidelberg (Germany); Wundt, B.J. [Missouri University of Science and Technology, Department of Physics, Rolla, MO (United States)
2012-02-15
The quantum field theory of superluminal (tachyonic) particles is plagued by a number of problems, which include the Lorentz non-invariance of the vacuum state, the ambiguous separation of the field operator into creation and annihilation operators under Lorentz transformations, and the necessity of a complex reinterpretation principle for quantum processes. Another unsolved question concerns the treatment of subluminal components of a tachyonic wave packet in the field-theoretical formalism, and the calculation of the time-ordered propagator. After a brief discussion on related problems, we conclude that rather painful choices have to be made in order to incorporate tachyonic spin- (1)/(2) particles into field theory. We argue that the field theory needs to be formulated such as to allow for localizable tachyonic particles, even if that means that a slight unitarity violation is introduced into the S matrix, and we write down field operators with unrestricted momenta. We find that once these choices have been made, the propagator for the neutrino field can be given in a compact form, and the left-handedness of the neutrino as well as the right-handedness of the antineutrino follow naturally. Consequences for neutrinoless double beta decay and superluminal propagation of neutrinos are briefly discussed. (orig.)
Localizability of tachyonic particles and neutrinoless double beta decay
International Nuclear Information System (INIS)
Jentschura, U.D.; Wundt, B.J.
2012-01-01
The quantum field theory of superluminal (tachyonic) particles is plagued by a number of problems, which include the Lorentz non-invariance of the vacuum state, the ambiguous separation of the field operator into creation and annihilation operators under Lorentz transformations, and the necessity of a complex reinterpretation principle for quantum processes. Another unsolved question concerns the treatment of subluminal components of a tachyonic wave packet in the field-theoretical formalism, and the calculation of the time-ordered propagator. After a brief discussion on related problems, we conclude that rather painful choices have to be made in order to incorporate tachyonic spin- (1)/(2) particles into field theory. We argue that the field theory needs to be formulated such as to allow for localizable tachyonic particles, even if that means that a slight unitarity violation is introduced into the S matrix, and we write down field operators with unrestricted momenta. We find that once these choices have been made, the propagator for the neutrino field can be given in a compact form, and the left-handedness of the neutrino as well as the right-handedness of the antineutrino follow naturally. Consequences for neutrinoless double beta decay and superluminal propagation of neutrinos are briefly discussed. (orig.)
$\\beta$ - decay asymmetry in mirror nuclei: A = 9
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...
Cosmological implications of Dark Matter bound states
Energy Technology Data Exchange (ETDEWEB)
Mitridate, Andrea [Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126, Pisa (Italy); Redi, Michele; Smirnov, Juri [INFN, Sezione di Firenze, and Dipartimento di Fisica e Astronomia, Università di Firenze, Via G. Sansone 1, 50019 Sesto Fiorentino (Italy); Strumia, Alessandro, E-mail: andrea.mitridate@gmail.com, E-mail: michele.redi@fi.infn.it, E-mail: juri.smirnov@mpi-hd.mpg.de, E-mail: alessandro.strumia@cern.ch [Dipartimento di Fisica dell' Università di Pisa and INFN, Pisa (Italy)
2017-05-01
We present generic formulæ for computing how Sommerfeld corrections together with bound-state formation affects the thermal abundance of Dark Matter with non-abelian gauge interactions. We consider DM as a fermion 3plet (wino) or 5plet under SU(2) {sub L} . In the latter case bound states raise to 11.5 TeV the DM mass required to reproduce the cosmological DM abundance and give indirect detection signals such as (for this mass) a dominant γ-line around 70 GeV. Furthermore, we consider DM co-annihilating with a colored particle, such as a squark or a gluino, finding that bound state effects are especially relevant in the latter case.
A note on BPS vortex bound states
Directory of Open Access Journals (Sweden)
A. Alonso-Izquierdo
2016-02-01
Full Text Available In this note we investigate bound states, where scalar and vector bosons are trapped by BPS vortices in the Abelian Higgs model with a critical ratio of the couplings. A class of internal modes of fluctuation around cylindrically symmetric BPS vortices is characterized mathematically, analyzing the spectrum of the second-order fluctuation operator when the Higgs and vector boson masses are equal. A few of these bound states with low values of quantized magnetic flux are described fully, and their main properties are discussed.
A note on BPS vortex bound states
Energy Technology Data Exchange (ETDEWEB)
Alonso-Izquierdo, A., E-mail: alonsoiz@usal.es [Departamento de Matematica Aplicada, Universidad de Salamanca (Spain); Garcia Fuertes, W., E-mail: wifredo@uniovi.es [Departamento de Fisica, Universidad de Oviedo (Spain); Mateos Guilarte, J., E-mail: guilarte@usal.es [Departamento de Fisica Fundamental, Universidad de Salamanca (Spain)
2016-02-10
In this note we investigate bound states, where scalar and vector bosons are trapped by BPS vortices in the Abelian Higgs model with a critical ratio of the couplings. A class of internal modes of fluctuation around cylindrically symmetric BPS vortices is characterized mathematically, analyzing the spectrum of the second-order fluctuation operator when the Higgs and vector boson masses are equal. A few of these bound states with low values of quantized magnetic flux are described fully, and their main properties are discussed.
First results of neutrinoless double beta decay search with the GERmanium Detector Array "GERDA"
Janicskó Csáthy, József
2014-06-01
The study of neutrinoless double beta decay is the most powerful approach to the fundamental question if the neutrino is a Majorana particle, i.e. its own anti-particle. The observation of the lepton number violating neutrinoless double beta decay would establish the Majorana nature of the neutrino. Until now neutrinoless double beta decay was not observed. The GERmanium Detector Array, GERDA is a double beta decay experiment located at the INFN Gran Sasso National Laboratory, Italy. GERDA operates bare Ge diodes enriched in 76Ge in liquid argon supplemented by a water shield. The exposure accumulated adds up to 21.6 kg· yr with a background level of 1.8 · 10-2 cts/(keV·kg·yr). The results of the Phase I of the experiment are presented and the preparation of the Phase II is briefly discussed.
Probing new physics models of neutrinoless double beta decay with SuperNEMO
Energy Technology Data Exchange (ETDEWEB)
Arnold, R. [CNRS/IN2P3, IPHC, Universite de Strasbourg, Strasbourg (France); Augier, C.; Bongrand, M.; Garrido, X.; Jullian, S.; Sarazin, X.; Simard, L. [CNRS/IN2P3, LAL, Universite Paris-Sud 11, Orsay (France); Baker, J.; Caffrey, A.J.; Horkley, J.J.; Riddle, C.L. [INL, Idaho Falls, ID (United States); Barabash, A.S.; Konovalov, S.I.; Umatov, V.I.; Vanyushin, I.A. [Institute of Theoretical and Experimental Physics, Moscow (Russian Federation); Basharina-Freshville, A.; Evans, J.J.; Flack, R.; Holin, A.; Kauer, M.; Richards, B.; Saakyan, R.; Thomas, J.; Vasiliev, V.; Waters, D. [University College London, London (United Kingdom); Brudanin, V.; Egorov, V.; Kochetov, O.; Nemchenok, I.; Timkin, V.; Tretyak, V.; Vasiliev, R. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Cebrian, S.; Dafni, T.; Irastorza, I.G.; Gomez, H.; Iguaz, F.J.; Luzon, G.; Rodriguez, A. [University of Zaragoza, Zaragoza (Spain); Chapon, A.; Durand, D.; Guillon, B.; Mauger, F. [Universite de Caen, LPC Caen, ENSICAEN, Caen (France); Chauveau, E.; Hubert, P.; Hugon, C.; Lutter, G.; Marquet, C.; Nachab, A.; Nguyen, C.H.; Perrot, F.; Piquemal, F.; Ricol, J.S. [UMR 5797, Universite de Bordeaux, Centre d' Etudes Nucleaires de Bordeaux Gradignan, Gradignan (France); UMR 5797, CNRS/IN2P3, Centre d' Etudes Nucleaires de Bordeaux Gradignan, Gradignan (France); Deppisch, F.F.; Jackson, C.M.; Nasteva, I.; Soeldner-Rembold, S. [Univ. of Manchester (United Kingdom); Diaz, J.; Monrabal, F.; Serra, L.; Yahlali, N. [CSIC - Univ. de Valencia, IFIC (Spain); Fushima, K.I. [Tokushima Univ., Tokushima (Japan); Holy, K.; Povinec, P.P.; Simkovic, F. [Comenius Univ., FMFI, Bratislava (Slovakia); Ishihara, N. [KEK, Tsukuba, Ibaraki (Japan); Kovalenko, V. [CNRS/IN2P3, IPHC, Univ. de Strasbourg (France); Joint Inst. for Nuclear Research, Dubna (Russian Federation); Lamhamdi, T. [USMBA, Fes (Morocco); Lang, K.; Pahlka, R.B. [Univ. of Texas, Austin, TX (United States)] (and others)
2010-12-15
The possibility to probe new physics scenarios of light Majorana neutrino exchange and right-handed currents at the planned next generation neutrinoless double {beta} decay experiment SuperNEMO is discussed. Its ability to study different isotopes and track the outgoing electrons provides the means to discriminate different underlying mechanisms for the neutrinoless double {beta} decay by measuring the decay half-life and the electron angular and energy distributions. (orig.)
Molecular effects in the neutrino mass determination from beta-decay of the tritium molecule
International Nuclear Information System (INIS)
Fackler, O.; Jeziorski, B.; Kolos, W.; Szalewicz, K.; Monkhorst, H.J.; Mugge, M.
1986-03-01
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
Bound States in the Mirror TBA
Arutyunov, G.E.; Frolov, S.; van Tongeren, S.J.
2012-01-01
The spectrum of the light-cone AdS_5 \\times S^5 superstring contains states composed of particles with complex momenta including in particular those which turn into bound states in the decompactification limit. We propose the mirror TBA description for these states. We focus on a three-particle
Scattering theory methods for bound state problems
International Nuclear Information System (INIS)
Raphael, R.B.; Tobocman, W.
1978-01-01
For the analysis of the properties of a bound state system one may use in place of the Schroedinger equation the Lippmann-Schwinger (LS) equation for the wave function or the LS equation for the reactance operator. Use of the LS equation for the reactance operator constrains the solution to have correct asymptotic behaviour, so this approach would appear to be desirable when the bound state wave function is to be used to calculate particle transfer form factors. The Schroedinger equation based N-level analysis of the s-wave bound states of a square well is compared to the ones based on the LS equation. It is found that the LS equation methods work better than the Schroedinger equation method. The method that uses the LS equation for the wave function gives the best results for the wave functions while the method that uses the LS equation for the reactance operator gives the best results for the binding energies. The accuracy of the reactance operator based method is remarkably insensitive to changes in the oscillator constant used for the harmonic oscillator function basis set. It is also remarkably insensitive to the number of nodes in the bound state wave function. (Auth.)
A study of beta decay energies and atomic masses
International Nuclear Information System (INIS)
Spanier, L.
1988-04-01
The q β energies of 123-131 In have been determined using the end points of β spectra recorded in β-γ coincidence experiments. A HPGe planar detector was used to detect the β-particles and a semi-empirical response function was used when unfolding the electron distribution. The mass excesses were deduced and when they were compared with the predictions of various mass formulae, the cadmium isotopes were found to be heavier than those predicted by most of the mass formulae. The excitation energy of the 1/2 - proton-hole state in the odd indium isotopes was shown to be constant for all the heavy isotopes. The Q EC energies of 148 Dy and 96 Pd were determined using the β + /EC intensity ratio method. The ratio of the intensity of the β+ branch to the total beta decay intensity was determined by means of γ-spectroscopic methods. The mass excesses were deduced. The two-proton binding energy for the N=82 isotones showed only a small step of approximately 0.5 MeV when the doubly-magic nucleus 146 Gd was encountered. A liquid drop type mass formula with deformation and shell energy corrections and with few free parameters is presented. The shell energy correction is a simple analytical expression for the equilibrium deformation of the nucleus. An analytical expression for the equilibrium nuclear deformation is also presented. The mass formula was applied to nuclei with Z and N greater than 50. The RMS deviation is 0.55 milli mass units. The reaction 98 Mo(p,n) 98 Tc was investigated through the counter ratio method, the ratio of the number of slow neutrons to the number of fast neutrons. The Q pn energy value of a low-spin state in 98 Tc was determined. The state at 90.9 keV excitation energy is proposed to be the 14.6 m u s isomer and have spin and parity 1 + . (author)
Analysis of super-allowed Fermi beta-decay
Energy Technology Data Exchange (ETDEWEB)
Wilkinson, D H [TRIUMF, Vancouver, BC (Canada); [Sussex Univ., Brighton (United Kingdom)
1994-11-01
Analysis of tile J{pi} = 0{sup +} {yields} 0{sup +} 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 IV{sub ud}I{sup 2} + IV{sub us}I{sup 2} + IV{sub ub}I{sup 2} = 1.0003 {+-} 0.0014. The associated value for the operational vector coupling constant is: G{sub v}{sup *} / (hc){sup 3} = (1.15155{+-}0.00064) x 10{sup -5} GeV{sup -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, b{sub F} < 2.6 x 10{sup -3} were b{sub F} is the relative effective scalar
Neutron Interactions in the CUORE Neutrinoless Double Beta Decay Experiment
Energy Technology Data Exchange (ETDEWEB)
Dolinski, Michelle Jean [Univ. of California, Berkeley, CA (United States)
2008-10-01
Neutrinoless double beta decay (0vDBD) is a lepton-number violating process that can occur only for a massive Majorana neutrino. The search for 0vDBD is currently the only practical experimental way to determine whether neutrinos are identical to their own antiparticles (Majorana neutrinos) or have distinct particle and anti-particle states (Dirac neutrinos). In addition, the observation of 0vDBD can provide information about the absolute mass scale of the neutrino. The Cuoricino experiment was a sensitive search for 0vDBD, as well as a proof of principle for the next generation experiment, CUORE. CUORE will search for 0vDBD of ^{130}Te with a ton-scale array of unenriched TeO_{2} bolometers. By increasing mass and decreasing the background for 0vDBD, the half-life sensitivity of CUORE will be a factor of twenty better than that of Cuoricino. The site for both of these experiments is the Laboratori Nazionali del Gran Sasso, an underground laboratory with 3300 meters water equivalent rock overburden and a cosmic ray muon attenuation factor of 10^{-6}. Because of the extreme low background requirements for CUORE, it is important that all potential sources of background in the 0vDBD peak region at 2530 keV are well understood. One potential source of background for CUORE comes from neutrons, which can be produced underground both by (α,n) reactions and by fast cosmic ray muon interactions. Preliminary simulations by the CUORE collaboration indicate that these backgrounds will be negligible for CUORE. However, in order to accurately simulate the expected neutron background, it is important to understand the cross sections for neutron interactions with detector materials. In order to help refine these simulations, I have measured the gamma-ray production cross sections for interactions of neutrons on the abundant stable isotopes of Te using the GEANIE detector array at the Los Alamos Neutron Science Center. In addition, I have used the GEANIE
Analysis of super-allowed Fermi beta-decay
International Nuclear Information System (INIS)
Wilkinson, D.H.
1994-11-01
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 IV ud I 2 + IV us I 2 + IV ub I 2 = 1.0003 ± 0.0014. The associated value for the operational vector coupling constant is: G v * / (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, b F -3 were b F is the relative effective scalar coupling constant. Neutron decay is also discussed, with the provisional recommendations: G A * /(hc) 3
Yukawa Bound States and Their LHC Phenomenology
Directory of Open Access Journals (Sweden)
Enkhbat Tsedenbaljir
2013-01-01
Full Text Available We present the current status on the possible bound states of extra generation quarks. These include phenomenology and search strategy at the LHC. If chiral fourth-generation quarks do exist their strong Yukawa couplings, implied by current experimental lower bound on their masses, may lead to formation of bound states. Due to nearly degenerate 4G masses suggested by Precision Electroweak Test one can employ “heavy isospin” symmetry to classify possible spectrum. Among these states, the color-octet isosinglet vector ω 8 is the easiest to be produced at the LHC. The discovery potential and corresponding decay channels are covered in this paper. With possible light Higgs at ~125 GeV two-Higgs doublet version is briefly discussed.
Bound states in weakly disordered spin ladders
Energy Technology Data Exchange (ETDEWEB)
Arlego, M. [Departamento de Fisica, Universidad Nacional de La Plata, CC 67 (1900) La Plata (Argentina)]. E-mail: arlego@venus.fisica.unlp.edu.ar; Brenig, W. [Institut fuer Theoretische Physik, Technische Universitaet Braunschweig (Germany); Cabra, D.C. [Laboratoire de Physique Theorique, Universite Louis Pasteur Strasbourg (France); Heidrich-Meisner, F. [Institut fuer Theoretische Physik, Technische Universitaet Braunschweig (Germany); Honecker, A. [Institut fuer Theoretische Physik, Technische Universitaet Braunschweig (Germany); Rossini, G. [Departamento de Fisica, Universidad Nacional de La Plata, CC 67 (1900) La Plata (Argentina)
2005-04-30
We study the appearance of bound states in the spin gap of spin-12 ladders induced by weak bond disorder. Starting from the strong-coupling limit, i.e., the limit of weakly coupled dimers, we perform a projection on the single-triplet subspace and derive the position of bound states for the single impurity problem of one modified coupling as well as for small impurity clusters. The case of a finite concentration of impurities is treated with the coherent-potential approximation (CPA) in the strong-coupling limit and compared with numerical results. Further, we analyze the details in the structure of the density of states and relate their origin to the influence of impurity clusters.
Closed form bound-state perturbation theory
Directory of Open Access Journals (Sweden)
Ollie J. Rose
1980-01-01
Full Text Available The perturbed Schrödinger eigenvalue problem for bound states is cast into integral form using Green's Functions. A systematic algorithm is developed and applied to the resulting equation giving rise to approximate solutions expressed as functions of the given perturbation parameter. As a by-product, convergence radii for the traditional Rayleigh-Schrödinger and Brillouin-Wigner perturbation theories emerge in a natural way.
New approach to calculate bound state eigenvalues
International Nuclear Information System (INIS)
Gerck, E.; Gallas, J.A.C.
1983-01-01
A method of solving the radial Schrodinger equation for bound states is discussed. The method is based on a new piecewise representation of the second derivative operator on a set of functions that obey the boundary conditions. This representation is trivially diagonalised and leads to closed form expressions of the type E sub(n)=E(ab+b+c/n+...) for the eigenvalues. Examples are given for the power-law and logarithmic potentials. (Author) [pt
Construction of a 1 MeV Electron Accelerator for High Precision Beta Decay Studies
Longfellow, Brenden
2014-09-01
Beta decay energy calibration for detectors is typically established using conversion sources. However, the calibration points from conversion sources are not evenly distributed over the beta energy spectrum and the foil backing of the conversion sources produces perturbations in the calibration spectrum. To improve this, an external, tunable electron beam coupled by a magnetic field can be used to calibrate the detector. The 1 MeV electron accelerator in development at Triangle Universities Nuclear Laboratory (TUNL) utilizes a pelletron charging system. The electron gun shoots 104 electrons per second with an energy range of 50 keV to 1 MeV and is pulsed at a 10 kHz rate with a few ns width. The magnetic field in the spectrometer is 1 T and guiding fields of 0.01 to 0.05 T for the electron gun are used to produce a range of pitch angles. This accelerator can be used to calibrate detectors evenly over its energy range and determine the detector response over a range of pitch angles. Beta decay energy calibration for detectors is typically established using conversion sources. However, the calibration points from conversion sources are not evenly distributed over the beta energy spectrum and the foil backing of the conversion sources produces perturbations in the calibration spectrum. To improve this, an external, tunable electron beam coupled by a magnetic field can be used to calibrate the detector. The 1 MeV electron accelerator in development at Triangle Universities Nuclear Laboratory (TUNL) utilizes a pelletron charging system. The electron gun shoots 104 electrons per second with an energy range of 50 keV to 1 MeV and is pulsed at a 10 kHz rate with a few ns width. The magnetic field in the spectrometer is 1 T and guiding fields of 0.01 to 0.05 T for the electron gun are used to produce a range of pitch angles. This accelerator can be used to calibrate detectors evenly over its energy range and determine the detector response over a range of pitch angles
Fermionic bound states in distinct kinklike backgrounds
Energy Technology Data Exchange (ETDEWEB)
Bazeia, D. [Universidade Federal da Paraiba, Departamento de Fisica, Joao Pessoa, Paraiba (Brazil); Mohammadi, A. [Universidade Federal de Campina Grande, Departamento de Fisica, Caixa Postal 10071, Campina Grande, Paraiba (Brazil)
2017-04-15
This work deals with fermions in the background of distinct localized structures in the two-dimensional spacetime. Although the structures have a similar topological character, which is responsible for the appearance of fractionally charged excitations, we want to investigate how the geometric deformations that appear in the localized structures contribute to the change in the physical properties of the fermionic bound states. We investigate the two-kink and compact kinklike backgrounds, and we consider two distinct boson-fermion interactions, one motivated by supersymmetry and the other described by the standard Yukawa coupling. (orig.)
Andreev bound states. Some quasiclassical reflections
International Nuclear Information System (INIS)
Lin, Y.; Leggett, A. J.
2014-01-01
We discuss a very simple and essentially exactly solvable model problem which illustrates some nice features of Andreev bound states, namely, the trapping of a single Bogoliubov quasiparticle in a neutral s-wave BCS superfluid by a wide and shallow Zeeman trap. In the quasiclassical limit, the ground state is a doublet with a splitting which is proportional to the exponentially small amplitude for “normal” reflection by the edges of the trap. We comment briefly on a prima facie paradox concerning the continuity equation and conjecture a resolution to it
Andreev bound states. Some quasiclassical reflections
Energy Technology Data Exchange (ETDEWEB)
Lin, Y., E-mail: yiriolin@illinois.edu; Leggett, A. J. [University of Illinois at Urhana-Champaign, Dept. of Physics (United States)
2014-12-15
We discuss a very simple and essentially exactly solvable model problem which illustrates some nice features of Andreev bound states, namely, the trapping of a single Bogoliubov quasiparticle in a neutral s-wave BCS superfluid by a wide and shallow Zeeman trap. In the quasiclassical limit, the ground state is a doublet with a splitting which is proportional to the exponentially small amplitude for “normal” reflection by the edges of the trap. We comment briefly on a prima facie paradox concerning the continuity equation and conjecture a resolution to it.
Bound states in curved quantum waveguides
International Nuclear Information System (INIS)
Exner, P.; Seba, P.
1987-01-01
We study free quantum particle living on a curved planar strip Ω of a fixed width d with Dirichlet boundary conditions. It can serve as a model for electrons in thin films on a cylindrical-type substrate, or in a curved quantum wire. Assuming that the boundary of Ω is infinitely smooth and its curvature decays fast enough at infinity, we prove that a bound state with energy below the first transversal mode exists for all sufficiently small d. A lower bound on the critical width is obtained using the Birman-Schwinger technique. (orig.)
Double beta decay and majorana neutrinos. Right-handed currents or nonzero masses
International Nuclear Information System (INIS)
Rosen, S.P.; Perlmutter, A.
1981-01-01
This chapter describes some new developments concerning the mechanism for lepton number nonconservation in no-neutrino double beta decay. Explains that lepton number nonconservation in no-neutrino double beta decay comes about either because both left- and right-handed components of a Majorano neutrino are coupled to the electron in the weak leptonic current, or because the neutrino has nonzero mass. Shows that while nuclear ground-state to ground-state transitions arise from right-handed currents and from neutrino mass terms, transitions to low-lying excited states with J /SUP P/ =2 + can arise only from right-handed currents. Emphasizes that the possibilities of detecting small admixtures of right-handed currents, and of setting limits on neutrino masses that are either very small or very large, make double beta decay a most rewarding phenomenon to study
Double Beta Decay Experiments: Present Status and Prospects for the Future
Barabash, A. S.
The review of modern experiments on search and studying of double beta decay processes is done. Results of the most sensitive current experiments are discussed. The main attention is paid to EXO-200, KamLAND-Zen, GERDA-I and CUORE-0 experiments. Modern values of T1/2(2ν) and best present limits on neutrinoless double beta decay and double beta decay with Majoron emission are presented. Conservative limits on effective mass of a Majorana neutrino ( at the level of ˜ (0.01-0.1) eV are discussed. The main attention is paid to experiments of CUORE, GERDA, MAJORANA, EXO, KamLAND-Zen-2, SuperNEMO and SNO+. Possibilities of low-temperature scintillating bolometers on the basis of inorganic crystals (ZnSe, ZnMoO4, Li2MoO4, CaMoO4 and CdWO4) are considered too.
Q values of the 76Ge and 100Mo double-beta decays
International Nuclear Information System (INIS)
Rahaman, S.; Elomaa, V.-V.; Eronen, T.; Hakala, J.; Jokinen, A.; Julin, J.; Kankainen, A.; Saastamoinen, A.; Suhonen, J.; Weber, C.; Aystoe, J.
2008-01-01
Penning trap measurements using mixed beams of 76 Ge- 76 Se and 100 Mo- 100 Ru have been utilized to determine the double-beta decay Q-values of 76 Ge and 100 Mo with uncertainties less than 200 eV. The value for 76 Ge, 2039.04(16) keV is in agreement with the published SMILETRAP value, 2039.006(50) keV. The new value for 100 Mo, 3034.40(17) keV is 30 times more precise than the previous literature value, sufficient for the ongoing neutrinoless double-beta decay searches in 100 Mo. Moreover, the precise Q-value is used to calculate the phase-space integrals and the experimental nuclear matrix element of double-beta decay
The MAJORANA DEMONSTRATOR: A Search for Neutrinoless Double-beta Decay of Germanium-76
Energy Technology Data Exchange (ETDEWEB)
Schubert, Alexis G.; Aguayo, Estanislao; Avignone, F. T.; Zhang, C.; Back, Henning O.; Barabash, Alexander S.; Bergevin, M.; Bertrand, F.; Boswell, M.; Brudanin, V.; Busch, Matthew; Chan, Yuen-Dat; Christofferson, Cabot-Ann; Collar, J. I.; Combs, Dustin C.; Cooper, R. J.; Detwiler, Jason A.; Leon, Jonathan D.; Doe, Peter J.; Efremenko, Yuri; Egorov, Viatcheslav; Ejiri, H.; Elliott, S. R.; Esterline, James H.; Fast, James E.; Fields, N.; Finnerty, P.; Fraenkle, Florian; Gehman, Victor M.; Giovanetti, G. K.; Green, M.; Guiseppe, Vincente; Gusey, K.; Hallin, A. L.; Hazama, R.; Henning, Reyco; Hime, Andrew; Hoppe, Eric W.; Horton, Mark; Howard, Stanley; Howe, Mark; Johnson, R. A.; Keeter, K.; Keillor, Martin E.; Keller, C.; Kephart, Jeremy D.; Kidd, M. F.; Knecht, A.; Kochetov, Oleg; Konovalov, S.; Kouzes, Richard T.; LaFerriere, Brian D.; LaRoque, B. H.; Leviner, L.; Loach, J. C.; MacMullin, S.; Marino, Michael G.; Martin, R. D.; Mei, Dong-Ming; Merriman, Jason H.; Miller, M. L.; Mizouni, Leila; Nomachi, Masaharu; Orrell, John L.; Overman, Nicole R.; Phillips, D.; Poon, Alan; Perumpilly, Gopakumar; Prior, Gersende; Radford, D. C.; Rielage, Keith; Robertson, R. G. H.; Ronquest, M. C.; Shima, T.; Shirchenko, M.; Snavely, Kyle J.; Sobolev, V.; Steele, David; Strain, J.; Thomas, K.; Timkin, V.; Tornow, Werner; Vanyushin, I.; Varner, R. L.; Vetter, Kai; Vorren, Kris R.; Wilkerson, J. F.; Wolfe, B. A.; Yakushev, E.; Young, A.; Yu, Chang-Hong; Yumatov, Vladimir
2012-09-28
The observation of neutrinoless double-beta decay would determine whether the neutrino is a Majorana particle and provide information on the absolute scale of neutrino mass. The MAJORANA Collaboration is constructing the DEMONSTRATOR, an array of germanium detectors, to search for neutrinoless double-beta decay of 76Ge. The DEMONSTRATOR will contain 40 kg of germanium; up to 30 kg will be enriched to 86% in 76Ge. The DEMONSTRATOR will be deployed deep underground in an ultra-low-background shielded environment. Operation of the DEMONSTRATOR aims to determine whether a future tonne-scale germanium experiment can achieve a background goal of one count per tonne-year in a 4-keV region of interest around the 76Ge neutrinoless double-beta decay Q-value of 2039 keV.
Double beta decays and related subjects for particle and nuclear physics
International Nuclear Information System (INIS)
Ejiri, Hiroyasu
1991-01-01
Present status and some perspectives in 1990's are briefly given on double beta decays and related subjects. Subjects discussed are as follows I) Double beta decays without neutrinos, which require lepton number non-conservations and finite neutrino mass. II) Double beta decays followed by two neutrinos. III) Double weak processes with strangeness change ΔS = 2, leading to the H particle with 6 quarks of ss uu dd. IV) Charge non-conservation and electron decays. These are very rare nuclear processes studied by Ultra RAre-process NUclear Spectroscopy (URANUS). It is shown that URANUS is an important detector frontier of non-accelerator nuclear physics in 1990's. (orig.)
International Nuclear Information System (INIS)
Le Bas, P.A.
1984-01-01
Data on the mass of the anti-neutrino determined via electrostatic measurements of tritium beta-decay are assessed. Relativistic calculations concerning the finite mass of the electron anti-neutrino and the recoil of the nucleus, are given for the theoretical end-point spectrum of tritium beta-decay. The specifications are given for an electrostatic Spherical Retarding Beta-Spectrometer, and an electrostatic Cylindrical Mirror Analyser, both used in the tritium beta-decay experiment. The electrostatic measurements lead to a value of less than 50 ev (90% C.L.) for the electron anti-neutrino mass. These results are discussed in terms of the resolution of the electrostatic equipment and the Monte Carlo simulations of the data collection. (UK)
Search for 136Xe neutrinoless double beta decay with the Enriched Xenon Observatory (EXO)
International Nuclear Information System (INIS)
Giroux, G.
2014-01-01
The EXO collaboration is searching for the neutrinoless double beta decay of 136 Xe. Such observation would determine an absolute mass scale for the neutrinos, establish their Majorana nature, and uncover physics beyond the Standard Model. The EXO-200 detector is a single phase liquid xenon ultra low background TPC (Time Projection Chamber), with an active mass of 110 kg of 80.6% enriched xenon in the isotope 136. The detector is currently operating at the WIPP site and has been collecting data with enriched xenon since May 2011. The data collected give a lower limit for the neutrinoless double beta decay half-life of 136 Xe: T > 1.6*10 25 years at 90% C.L. The same data give a lower limit for the 2 neutrinos double beta decay of 136 Xe: T > 2.23*10 21 years that agrees with experimental values found in the literature
Study of octupole deformation in n-rich Ba isotopes populated via $\\beta$-decay
We propose to exploit the unique capability of the ISOLDE facility to produce $^{150, 151, 152}$Cs beams to investigate their radioactive $\\beta$-decay to $^{150, 151, 152}$Ba. The interest to study this mass region is twofold: these nuclei are expected to show octupole deformations already in their low-lying state, secondly information on the $\\beta$-decay is needed for the nuclear astrophysical model. The experiment will be performed with the ISOLDE Decay Station (IDS) setup using the fast tape station of K.U.-Leuven, equipped with four Clover Germanium detectors, four LaBr$_{3}$(Ce) detectors and one LEP HPGe detector. Information on the $\\beta$-decay, such as lifetimes and delayed neutron-emission probabilities, will be extracted, together with the detailed spectroscopy of the daughter nuclei, via $\\gamma$-$\\gamma$-coincidences and lifetime measurement of specific states.
Neutrino-Less Double Beta Decay - Experimentum Crucis of Neutrino Physics
International Nuclear Information System (INIS)
Sujkowski, Z.
2003-01-01
The presently most wanted information on neutrino properties concerns their mass values and their transformation properties under charge conjugation. The recent oscillation experiments prove that at least one of the three neutrino species has a non-vanishing rest mass and that the lepton flavour is not conserved. These findings have to be supplemented by data from phenomena of different kind in order to deduce the information needed. The most promising method proposed thus far to determine Majorana neutrino mass and thus to answer the two leading questions is to observe the neutrino-less double beta decay and to measure its rate. The physics of this process is discussed and the on-going and planned experimental search is reviewed. This search concentrates on the 0 + →0 + ground-to-ground state decay of β - β - emitters using calorimetric or β - -β - coincidence tracking techniques. The β + β + or β + EC decays are usually considered as less favourable because of longer half-lives, even though they offer some advantages in combating the background. The recent proposition of measuring the monoenergetic photon spectra accompanying the radiative neutrino-less double electron capture decay is discussed. The experimental advantages of this technique may off-set the generally longer life-times expected. (author)
Double beta decays studied by β-γ spectroscopy with a drift chamber
International Nuclear Information System (INIS)
Okada, K.; Ejiri, H.; Shibata, T.
1986-01-01
A large scale ultra low background β-γ spectrometer ELEGANTS-V for studying double beta decays(ββ) of /sup 100/Mo and/or /sup 150/Nd is designed and is now under construction. It consists of drift chambers for identification of tracks and vertex of two β-rays, thin NaI(T1) or plastic scintillators for β-rays energy and NaI(T1) counters for γ- and cosmic-rays. Specifications of the spectrometer; energy resolution, detection efficiency, possible background counting rate and available ββ sources, have been evaluated. The spectrometer has extremely high sensitivities of the neutrinoless ββ decays (0νββ), two neutrino ββ decays (2νββ) and neutrinoless ββ decays followed one boson (Majoron). It may detect 0νββ decays with half lives up to T/sub 1/2/ = 1.2- 1.7 . 10/sup 23/ year. This limit corresponds to one part of million for the Majoran neutrino mass in units of the electron mass and for the right-handed weak current in units of the left handed one
Measurement of beta decay periods for Fe-Ni neutrons rich isotopes
International Nuclear Information System (INIS)
Czajkowski, S.
1992-01-01
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
LUCIFER: a scintillating bolometer array for the search of neutrinoless double beta decay
International Nuclear Information System (INIS)
Cardani, Laura
2011-01-01
In spite of the high precision achieved in the field of neutrino oscillations, there are some fundamental questions that can not be addressed by a study of ths phenomenon. We do not know in fact the absolute mass of neutrino and weather it is a Dirac or a Majorana particle. The LUCIFER experiment, financed by the ERC-AdG, will play an important role in this field. This project aims to push beyond the actual technological limits the possibility of observation of the Neutrinoless Double Beta Decay (0νDBD). The detection of this extremely rare decay would indeed demonstrate that neutrino is a Majorana particle and, at the same time, would allow to set its absolute mass scale. LUCIFER will study the 0νDBD do 82 Se through ZnSe scintillating bolometers. Thanks to the simultaneous red-out of the heat and light produced by an interaction in the crystal, the background rate in the region of interest will be lower than 10 -3 counts/kg/keV/years. In the following, the expected performance of LUCIFER are discussed.
Bound-state perturbation theory and annihilation effects in positronium
International Nuclear Information System (INIS)
Abbasabadi, A.; Repko, W.W.
1987-01-01
Working in Coulomb gauge and using the lowest-order equation proposed by Barbieri and Remiddi it is calculated, in the one-loop order of perturbation theory, the decay rate and the energy shift of the ground states of parapositronium and orthopositronium, respectively. Our result for the decay rate agrees with that of Harris and Brown. For contribution of one-photon-annihilation channel to the energy shift, it is confirmed the result of Karplus and Klein. These results are derived completely within the bound-state formalism and avoid the necessity of performing on-mass-shell wave function and vertex renormalization subtractions
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.
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.)
Beta decay of polarized nuclei and the decay asymmetry of 8Li
International Nuclear Information System (INIS)
Bigelow, R.; Freedman, S.J.; Napolitano, J.; Quin, P.A.
1985-01-01
Under certain conditions, it is possible to produce vector-polarized radioactive nuclei in reactions with a polarized projectile and an unpolarized target. Using the intense polarized beams at the University of Wisconsin, the authors have begun a program to study the weak interaction through the beta decay of polarized nuclei produced in this way. Such experiments bear on tests of CVC in light nuclei, sensitive searches for second-class weak currents, and measurements of the weak vector-coupling constant. One may also deduce the values of certain matrix elements. Our effort is presently centering on a study of the energy dependence of the beta-decay asymmetry of 8 Li
The MAJORANA experiment: an ultra-low background search for neutrinoless double-beta decay
Energy Technology Data Exchange (ETDEWEB)
Phillips, D.; Aguayo Navarrete, Estanislao; Avignone, Frank T.; Back, Henning O.; Barabash, Alexander S.; Bergevin, M.; Bertrand, F.; Boswell, M.; Brudanin, V.; Busch, Matthew; Chan, Yuen-Dat; Christofferson, Cabot-Ann; Collar, J. I.; Combs, Dustin C.; Cooper, R. J.; Detwiler, Jason A.; Doe, Peter J.; Efremenko, Yuri; Egorov, Viatcheslav; Ejiri, H.; Elliott, Steven R.; Esterline, James H.; Fast, James E.; Fields, N.; Finnerty, P.; Fraenkle, Florian; Gehman, Victor; Giovanetti, G. K.; Green, Matthew P.; Guiseppe, Vincente; Gusey, K.; Hallin, A. L.; Hazama, R.; Henning, Reyco; Hime, Andrew; Hoppe, Eric W.; Horton, Mark; Howard, Stanley; Howe, M. A.; Johnson, R. A.; Keeter, K.; Keller, C.; Kidd, Mary; Knecht, A.; Kochetov, Oleg; Konovalov, S.; Kouzes, Richard T.; LaFerriere, Brian D.; LaRoque, B. H.; Leon, Jonathan D.; Leviner, L.; Loach, J. C.; MacMullin, S.; Marino, Michael G.; Martin, R. D.; Mei, Dong-Ming; Merriman, Jason H.; Miller, M. L.; Mizouni, Leila; Nomachi, Masaharu; Orrell, John L.; Overman, Nicole R.; Poon, Alan; Perumpilly, Gopakumar; Prior, Gersende; Radford, D. C.; Rielage, Keith; Robertson, R. G. H.; Ronquest, M. C.; Schubert, Alexis G.; Shima, T.; Shirchenko, M.; Snavely, Kyle J.; Steele, David; Strain, J.; Thomas, K.; Timkin, V.; Tornow, W.; Vanyushin, I.; Varner, R. L.; Vetter, Kai; Vorren, Kris R.; Wilkerson, J. F.; Wolfe, B. A.; Yakushev, E.; Young, A.; Yu, Chang-Hong; Yumatov, Vladimir; Zhang, C.
2012-12-01
The observation of neutrinoless double-beta decay would resolve the Majorana nature of the neutrino and could provide information on the absolute scale of the neutrino mass. The initial phase of the Majorana Experiment, known as the Demonstrator, will house 40 kg of Ge in an ultra-low background shielded environment at the 4850' level of the Sanford Underground Laboratory in Lead, SD. The objective of the Demonstrator is to validate whether a future 1-tonne experiment can achieve a background goal of one count per tonne-year in a narrow region of interest around the 76Ge neutrinoless double-beta decay peak.
On possible contribution of a leptoquark intermediate boson mechanism in the free neutron beta decay
International Nuclear Information System (INIS)
Gaponov, Yu.V.
2000-01-01
A possible mechanism of the virtual leptoquark scalar intermediate boson exchange connected with a contribution of the right-handed nucleon currents to the free beta decay is demonstrated. The extension of the hypothesis can be associated with the realization of the same mechanism in the beta decay via the emission of right-handed neutrino (left-handed antineutrino). It is shown that a hypothesis of this kind leads to appearance of scalar and tensor terms in the effective Hamiltonian of weak interaction, and these terms include the right-handed neutrinos. The relevant experimental data are discussed [ru
Search for neutrinoless double beta decay in {sup 136}Xe with EXO-200
Energy Technology Data Exchange (ETDEWEB)
Feldmeier, Wolfhart
2015-02-19
Several properties of neutrinos, such as their absolute mass, their possible Majorana nature or the mechanisms that lead to small neutrino masses, are still unknown. The EXO-200 experiment is trying to answer some of these questions by searching for the hypothetical neutrinoless double beta decay of the isotope {sup 136}Xe. This thesis describes an analysis of two years of detector data, which yields a lower limit on the half-life of neutrinoless double beta decay of {sup 136}Xe of 1.1 x 10{sup 25} years.
The relative importance of relativistic induced interactions in the beta decay of 170Tm
International Nuclear Information System (INIS)
Bogdan, D.; Cristu, M.I.; Holan, S.; Faessler, A.
1982-09-01
The log ft-values, the spectrum shape functions, and the beta-gamma angular correlation coefficients of the 170 Tm beta decay are computed in the framework of relativistic formfactor formalism using asymmetric rotor model wavefunctions. Main vector and axial vector hadron currents being strongly hindered, the relative importance of induced interaction matrix elements is accurately estimated. Good agreement with experiment is obtained for the beta decay observables when the main induced interaction terms were taken into account. The contribution of the pseudoscalar term was found insignificant. (authors)
Development of a radiofrequency linear ion trap for {beta} decay study
Energy Technology Data Exchange (ETDEWEB)
Li, G. [McGill Univ., Montreal, Quebec (Canada); Argonne National Laboratory, Argonne, Illinois (United States); Scielzo, N.D. [Lawrence Livermore National Laboratory, Livermore, California (United States); Segel, R.E. [Northwestern Univ., Illinois (United States); and others
2010-07-01
A Beta decay Paul Trap (BPT) has been constructed at Argonne National Laboratory for the precise measurement of beta decay. We have demonstrated the capability of producing and transferring a low-energy, bunched, and isotopically pure ions beam. In BPT the ions are cooled to sub-eV energies, and confined in a volume of less than 1 mm{sup 3}. The trap has an open geometry which allows four sets of radiation detectors covering a substantial potion of solid angle. In combination with versatile detectors, BPT is able to precisely determine the entire decay kinematics of many isotopes. (author)
$\\beta$-decay studies using total absorption techniques some recent results
Algora, A; García-Borge, M J; Cano-Ott, D; Collatz, R; Courtin, S; Dessagne, P; Fraile-Prieto, L M; Gadea, A; Gelletly, W; Hellström, M; Janas, Z; Jungclaus, A; Karny, M; Kirchner, R; Maréchal, F; Miehé, C; Moroz, F; Nacher, E; Poirier, E; Roeckl, E; Rubio, B; Rykaczewski, K; Scornet, G L; Taín, J L; Tengblad, O; Wittmann, V
2004-01-01
$\\beta$-decay experiments, are a primary source of information for nuclear structure studies and at the same time complementary to in-beam investigations far from stability. Although both types of experiment are mainly based on $\\gamma$-ray spectroscopy, they face different experimental problems. The so-called $\\textit{Pandemonium effect}$ is a critical problem in $\\beta$-decay. In this contribution we will present a solution to this problem using total absorption spectroscopy methods. We will also present some examples of experiments carried out with the total absorption spectrometers TAS at GSI and Lucrecia recently installed at CERN. (25 refs).
Beta-decay studies using total absorption techniques: some recent results
Energy Technology Data Exchange (ETDEWEB)
Algora, A.; Rubio, B.; Nacher, E.; Cano O, D.; Tain, J.L.; Gadea, A. [lnstituto de Fisica Corpuscular, Apartado Oficial 22085, 46071 Valencia (Spain); Batist, L.; Moroz, F.; Wittmann, V. [St. Petersburg Nuclear Physics Institute, RU-188-350 Gatchina, (Russian Federation); Borge, M.J.G.; Jungclaus, A.; Tengblad, O. [Instituto Estructura de la Materia, E-28006 Madrid (Spain); Collatz, R.; Hellstrom, M.; Kirchner, R.; Roeckl, E. [Gesellschaft fur Schwerionenforschung, D-64291 Darmstadt (Germany); Courtin, H.; Dessagne, Ph.; Miehe, C.; Marechal, F.; Poirier, E. [lnstitut de Recherches Subatomiques, IN2P3-CNRS, F-67037 Strassbourg Cedex 2 (France); Fraile, L.M. [ISOLDE, Division EP, CERN, CH-1211 Geneva (Switzerland); Gelletly, W. [University of Surrey, Guildford GU2 7XH (United Kingdom); Janas, Z.; Karny, M.; Rykaczewski, K. [University of Warsaw, PL-00-681, Warsaw (Poland); Le Scornet, G. [CSNSM, 91405 Orsay (France)
2004-12-01
Beta-decay experiments are a primary source of information for nuclear structure studies and at the same time complementary to in-beam investigations far from stability. Although both types of experiment are mainly based on {gamma} ray spectroscopy, they face different experimental problems. The so called Pandemonium effect [1] is a critical problem in {beta}-decay. In this contribution we will present a solution to this problem using total absorption spectroscopy methods. We will also present some examples of experiments carried out with the total absorption spectrometers TAS at GSI and Lucrecia recently installed at CERN. (Author) 25 refs., 4 figs.
Energy Technology Data Exchange (ETDEWEB)
Alduino, C.; Avignone, F.T.; Chott, N.; Creswick, R.J.; Rosenfeld, C.; Wilson, J. [University of South Carolina, Department of Physics and Astronomy, Columbia, SC (United States); Alfonso, K.; Hickerson, K.P.; Huang, H.Z.; Liu, X.; Trentalange, S.; Zhu, B.X. [University of California, Department of Physics and Astronomy, Los Angeles, CA (United States); Artusa, D.R. [University of South Carolina, Department of Physics and Astronomy, Columbia, SC (United States); INFN-Laboratori Nazionali del Gran Sasso, Assergi, L' Aquila (Italy); Azzolini, O.; Camacho, A.; Keppel, G.; Palmieri, V.; Pira, C. [INFN-Laboratori Nazionali di Legnaro, Legnaro, Padova (Italy); Banks, T.I.; Drobizhev, A.; Freedman, S.J.; Hennings-Yeomans, R.; O' Donnell, T.; Wagaarachchi, S.L. [University of California, Department of Physics, Berkeley, CA (United States); Lawrence Berkeley National Laboratory, Nuclear Science Division, Berkeley, CA (United States); Bari, G.; Deninno, M.M. [INFN-Sezione di Bologna, Bologna (Italy); Beeman, J.W. [Lawrence Berkeley National Laboratory, Materials Science Division, Berkeley, CA (United States); Bellini, F.; Cardani, L.; Casali, N.; Cosmelli, C.; Ferroni, F. [Sapienza Universita di Roma, Dipartimento di Fisica, Rome (Italy); INFN-Sezione di Roma, Rome (Italy); Bersani, A.; Caminata, A. [INFN-Sezione di Genova, Genova (Italy); Biassoni, M.; Carbone, L.; Cremonesi, O.; Ferri, E.; Giachero, A.; Pessina, G.; Previtali, E.; Rusconi, C. [INFN-Sezione di Milano Bicocca, Milan (Italy); Brofferio, C.; Capelli, S.; Carniti, P.; Cassina, L.; Chiesa, D.; Clemenza, M.; Faverzani, M.; Fiorini, E.; Gironi, L.; Gotti, C.; Maino, M.; Nucciotti, A.; Pavan, M.; Pozzi, S.; Sisti, M.; Terranova, F.; Zanotti, L. [Universita di Milano-Bicocca, Dipartimento di Fisica, Milan (Italy); INFN-Sezione di Milano Bicocca, Milan (Italy); Bucci, C.; Cappelli, L.; D' Addabbo, A.; Di Vacri, M.L.; Gorla, P.; Pattavina, L.; Pirro, S. [INFN-Laboratori Nazionali del Gran Sasso, Assergi, L' Aquila (Italy); Canonica, L. [INFN-Laboratori Nazionali del Gran Sasso, Assergi, L' Aquila (Italy); Massachusetts Institute of Technology, Cambridge, MA (United States); Cao, X.G.; Fang, D.Q.; Ma, Y.G.; Wang, H.W.; Zhang, G.Q. [Chinese Academy of Sciences, Shanghai Institute of Applied Physics, Shanghai (China); Copello, S.; Di Domizio, S.; Fernandes, G.; Marini, L.; Pallavicini, M. [INFN-Sezione di Genova, Genova (Italy); Universita di Genova, Dipartimento di Fisica, Genova (Italy); Cushman, J.S.; Davis, C.J.; Heeger, K.M.; Lim, K.E.; Maruyama, R.H. [Yale University, Department of Physics, New Haven, CT (United States); Dafinei, I.; Morganti, S.; Mosteiro, P.J.; Orio, F.; Pettinacci, V.; Tomei, C.; Vignati, M. [INFN-Sezione di Roma, Rome (Italy); Dell' Oro, S. [INFN-Laboratori Nazionali del Gran Sasso, Assergi, L' Aquila (Italy); INFN-Gran Sasso Science Institute, L' Aquila (Italy); Feintzeig, J.; Fujikawa, B.K.; Mei, Y.; Smith, A.R. [Lawrence Berkeley National Laboratory, Nuclear Science Division, Berkeley, CA (United States); Franceschi, M.A.; Ligi, C.; Napolitano, T.; Piperno, G. [INFN-Laboratori Nazionali di Frascati, Frascati, Rome (Italy); Giuliani, A.; Tenconi, M. [Universite Paris-Saclay, CSNSM, Univ. Paris-Sud, CNRS/IN2P3, Orsay (France); Gladstone, L.; Leder, A.; Winslow, L.A. [Massachusetts Institute of Technology, Cambridge, MA (United States); Gutierrez, T.D. [California Polytechnic State University, Physics Department, San Luis Obispo, CA (United States); Haller, E.E. [Lawrence Berkeley National Laboratory, Materials Science Division, Berkeley, CA (United States); University of California, Department of Materials Science and Engineering, Berkeley, CA (United States); Han, K. [Yale University, Department of Physics, New Haven, CT (United States); Shanghai Jiao Tong University, Department of Physics and Astronomy, Shanghai (China); Hansen, E. [University of California, Department of Physics and Astronomy, Los Angeles, CA (United States); Massachusetts Institute of Technology, Cambridge, MA (United States); Kadel, R. [Lawrence Berkeley National Laboratory, Physics Division, Berkeley, CA (United States); Kolomensky, Yu.G. [University of California, Department of Physics, Berkeley, CA (United States); Lawrence Berkeley National Laboratory, Nuclear Science Division, Berkeley, CA (United States); Lawrence Berkeley National Laboratory, Physics Division, Berkeley, CA (United States); Martinez, M. [Sapienza Universita di Roma, Dipartimento di Fisica, Rome (Italy); INFN-Sezione di Roma, Rome (Italy); Universidad de Zaragoza, Laboratorio de Fisica Nuclear y Astroparticulas, Zaragoza (Spain); Moggi, N. [INFN-Sezione di Bologna, Bologna (Italy); Alma Mater Studiorum-Universita di Bologna, Dipartimento di Scienze per la Qualita della Vita, Bologna (Italy); Nones, C. [Service de Physique des Particules, CEA/Saclay, Gif-sur-Yvette (France); Norman, E.B.; Wang, B.S. [Lawrence Livermore National Laboratory, Livermore, CA (United States); University of California, Department of Nuclear Engineering, Berkeley, CA (United States); Ouellet, J.L. [University of California, Department of Physics, Berkeley, CA (United States); Lawrence Berkeley National Laboratory, Nuclear Science Division, Berkeley, CA (United States); Massachusetts Institute of Technology, Cambridge, MA (United States); Pagliarone, C.E. [INFN-Laboratori Nazionali del Gran Sasso, Assergi, L' Aquila (Italy); Universita degli Studi di Cassino e del Lazio Meridionale, Dipartimento di Ingegneria Civile e Meccanica, Cassino (Italy); Sangiorgio, S.; Scielzo, N.D. [Lawrence Livermore National Laboratory, Livermore, CA (United States); Santone, D. [INFN-Laboratori Nazionali del Gran Sasso, Assergi, L' Aquila (Italy); Universita dell' Aquila, Dipartimento di Scienze Fisiche e Chimiche, L' Aquila (Italy); Singh, V. [University of California, Department of Physics, Berkeley, CA (US); Taffarello, L. [INFN-Sezione di Padova, Padova (IT); Wise, T. [Yale University, Department of Physics, New Haven, CT (US); University of Wisconsin, Department of Physics, Madison, WI (US); Woodcraft, A. [University of Edinburgh, SUPA, Institute for Astronomy, Edinburgh (GB); Zimmermann, S. [Lawrence Berkeley National Laboratory, Engineering Division, Berkeley, CA (US); Zucchelli, S. [INFN-Sezione di Bologna, Bologna (IT); Alma Mater Studiorum-Universita di Bologna, Dipartimento di Fisica e Astronomia, Bologna (IT)
2017-01-15
We report on the measurement of the two-neutrino double-beta decay half-life of {sup 130}Te with the CUORE-0 detector. From an exposure of 33.4 kg year of TeO{sub 2}, the half-life is determined to be T{sub 1/2}{sup 2ν} = [8.2 ± 0.2 (stat.) ± 0.6 (syst.)] x 10{sup 20} year. This result is obtained after a detailed reconstruction of the sources responsible for the CUORE-0 counting rate, with a specific study of those contributing to the {sup 130}Te neutrinoless double-beta decay region of interest. (orig.)
Beta-decay of {sup 103}In: evidence for the Gamow-Teller resonance near {sup 100}Sn
Energy Technology Data Exchange (ETDEWEB)
Karny, M. [Warsaw Univ. (Poland). Inst. of Experimental Physics; Batist, L.; Brown, B.A. [and others
1998-04-01
The {beta} decay of the neutron-deficient isotope {sup 103}In was investigated by using total absorption {gamma}-ray spectrometry on mass-separated sources. The measurement reveals a high-lying resonance of the {beta}-decay strength in striking disagreement with high-resolution {gamma}-ray data. The result is discussed in comparison with shell-model predictions. (orig.)
Surface-bound states in nanodiamonds
Han, Peng; Antonov, Denis; Wrachtrup, Jörg; Bester, Gabriel
2017-05-01
We show via ab initio calculations and an electrostatic model that the notoriously low, but positive, electron affinity of bulk diamond becomes negative for hydrogen passivated nanodiamonds and argue that this peculiar situation (type-II offset with a vacuum level at nearly midgap) and the three further conditions: (i) a surface dipole with positive charge on the outside layer, (ii) a spherical symmetry, and (iii) a dielectric mismatch at the surface, results in the emergence of a peculiar type of surface state localized just outside the nanodiamond. These states are referred to as "surface-bound states" and have consequently a strong environmental sensitivity. These type of states should exist in any nanostructure with negative electron affinity. We further quantify the band offsets of different type of nanostructures as well as the exciton binding energy and contrast the results with results for "conventional" silicon quantum dots.
Models for light QCD bound states
International Nuclear Information System (INIS)
LaCourse, D.P.
1992-01-01
After a brief overview of Regge, tower, and heavy-quark experimental data, this thesis examines two massless wave equations relevant to quark bound states. We establish general conditions on the Lorentz scalar and Lorentz vector potentials which yield arbitrary leading Regge trajectories for the case of circular classical motion. A semi-classical approximation which includes radial motion reproduces remarkably well the exact solutions. Conditions for tower structure are examined, and found to be incompatible with conditions which give a Nambu stringlike Regge slope. The author then proposes a generalization of the usual potential model of quark bound states in which the confining flux tube is a dynamical object carrying both angular momentum and energy. The Q bar Q-string system with spinless quarks is quantized using an implicit operator technique and the resulting relativistic wave equation is solved. For heavy quarks the usual Schroedinger valence-quark model is recovered. The Regge slope with light quarks agree with the classical rotating-string result and is significantly larger and the effects of short-range forces are also considered. A relativistic generalization of the quantized flux tube model predicts the glueball ground state mass to be √3/α' ≅ 1.9 GeV where α' is the normal Regge slope. The groundstate as well as excited levels like considerably above the expectations of previous models and also above various proposed experimental candidates. The glueball Regge slope is only about three-eighths that for valence quark hadrons. A semi-classical calculation of the Regge slope is in good agreement with a numerically exact value
Generalized Solutions of the Dirac Equation, W Bosons, and Beta Decay
International Nuclear Information System (INIS)
Okniński, Andrzej
2016-01-01
We study the 7×7 Hagen-Hurley equations describing spin 1 particles. We split these equations, in the interacting case, into two Dirac equations with nonstandard solutions. It is argued that these solutions describe decay of a virtual W boson in beta decay.
Neutrinoless double-beta decay and dark matter search with GENIUS
International Nuclear Information System (INIS)
Klapdor-Kleingrothaus, H.V.; Kolb, S.
2000-01-01
The potential of the GENIUS (GErmanium in liquid NItrogen Underground Setup) experiment, proposed the successor of the Heidelberg-Moscow experiment, for the search for neutrinoless double-beta decay, the direct search for neutralino Cold Dark Matter and for other physics beyond the Standard Model are presented. The current status of the Heidelberg-Moscow experiment will be reviewed [ru
Neutrinoless double-beta decay and dark matter search with GENIUS
International Nuclear Information System (INIS)
Klapdor-Kleingrothaus, H.V.; Kolb, St.
2000-01-01
The potential of the GENIUS (GErmanium in liquid NItrogen Underground Setup) experiment, proposed as the successor of the Heidelberg-Moscow experiment, for the search for neutrinoless double-beta decay, the direct search for neutralino Cold Dark Matter, and for other physics beyond the Standard Model will be presented. The current status of the Heidelberg-Moscow experiment will be reviewed
New physics in the new millennium with GENIUS: double beta decay, dark matter, solar neutrinos
International Nuclear Information System (INIS)
Klapdor-Kleingrothaus, H.V.
2001-01-01
Double beta decay is indispensable to solve the question of the neutrino mass matrix together with ν oscillation experiments. The most sensitive experiment since eight years - the HEIDELBERG - MOSCOW experiment in Gran Sasso - already now, with the experimental limit of ν > 7 Be) solar neutrinos. A GENIUS Test Facility has just been funded and will come into operation by the end of 2001
The 76Ge Program to Search for Neutrinoless Double-Beta Decay
Guiseppe, Vincente
2017-09-01
Neutrinoless double-beta decay searches play a major role in determining the nature of neutrinos, the existence of a lepton violating process, and the effective Majorana neutrino mass. The Majorana and Gerda Collaborations are operating arrays of high purity Ge detectors to search for neutrinoless double-beta decay in 76Ge. The Majorana Demonstrator is operating at the Sanford Underground Research Facility in South Dakota while the Gerda experiment is operating at LNGS in Italy. The Gerda and Majorana Demonstrator experiments have achieved the lowest backgrounds in the neutrinoless double-beta decay region of interest. These results, coupled with the superior energy resolution (0.1%) of Ge detectors demonstrate that 76Ge is an ideal isotope for a large next generation experiment. The LEGEND collaboration, with 220 members from 47 institutions around the world, has been formed to pursue a ton scale 76Ge experiment. Building on the successes of Gerda and Majorana, the LEGEND collaboration aims to develop a phased neutrinoless double-beta decay experimental program with discovery potential at a half-life significantly longer than 1027 years. This talk will present the initial results from the Majorana Demonstrator and Gerda experiments and the plan for the LEGEND program.
Status of double beta decay experiments using isotopes other than 136Xe
Pandola, L.
2014-09-01
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 136Xe 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 76Ge 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 76Ge is T1/20ν > 2.1 ṡ1025 yr (90% C.L.), or T1/20ν > 3.0 ṡ1025 yr, when combined with the results of other 76Ge predecessor experiments.
Neutrinoless double beta decay in type I+II seesaw models
Energy Technology Data Exchange (ETDEWEB)
Borah, Debasish [Department of Physics, Tezpur University,Tezpur-784028 (India); Dasgupta, Arnab [Institute of Physics, Sachivalaya Marg,Bhubaneshwar-751005 (India)
2015-11-30
We study neutrinoless double beta decay in left-right symmetric extension of the standard model with type I and type II seesaw origin of neutrino masses. Due to the enhanced gauge symmetry as well as extended scalar sector, there are several new physics sources of neutrinoless double beta decay in this model. Ignoring the left-right gauge boson mixing and heavy-light neutrino mixing, we first compute the contributions to neutrinoless double beta decay for type I and type II dominant seesaw separately and compare with the standard light neutrino contributions. We then repeat the exercise by considering the presence of both type I and type II seesaw, having non-negligible contributions to light neutrino masses and show the difference in results from individual seesaw cases. Assuming the new gauge bosons and scalars to be around a TeV, we constrain different parameters of the model including both heavy and light neutrino masses from the requirement of keeping the new physics contribution to neutrinoless double beta decay amplitude below the upper limit set by the GERDA experiment and also satisfying bounds from lepton flavor violation, cosmology and colliders.
Status of the Frejus experiment on the neutrinoless double beta decay of the 76Ge
International Nuclear Information System (INIS)
Morales, A.; Nunez-Lagos, R.; Morales, J.; Puimedon, J.; Villar, J.A.; Dassie, D.; Hubbert, Ph.; Leccia, F.; Mennrath, P.; Villard, M.
1987-01-01
A brief account of the design, experimental set up and status of the Frejus experiments on the neutrinoless double beta decay of 76 Ge is presented. The theoretical implications and expectatives of this experimental research are analized. A comparison with other dedicated experiments is also reported. (author)
Observed double beta decay spectra from 82Se, 100Mo, and 150Nd
International Nuclear Information System (INIS)
Elliott, S.R.; Moe, M.K.; Nelson, M.A.; Vient, M.A.
1993-01-01
Two-electron events resembling double beta decay are being observed at energies beyond the die-off of the spectrum predicted for the two-neutrino mode. The anomaly appears in three isotopes having different half lives and Q-values. Tests are now underway to determine its origin. (orig.)
Internal Energy Loss of the Electrons Ejected in Neutrinoless Double Beta Decay
International Nuclear Information System (INIS)
Drukarev, E. G.; Amusia, M. Ya.; Chernysheva, L. V.
2017-01-01
The excitations of the electron shell in neutrinoless double beta decay shifts the limiting energy available for ejected electrons. We present the general equations for this shift and make computations for the decays of two nuclei—germanium and xenon. (author)
Double Beta Decay and Neutrino Masses Accuracy of the Nuclear Matrix Elements
International Nuclear Information System (INIS)
Faessler, Amand
2005-01-01
The neutrinoless double beta decay is forbidden in the standard model of the electroweak and strong interaction but allowed in most Grand Unified Theories (GUT's). Only if the neutrino is a Majorana particle (identical with its antiparticle) and if it has a mass, the neutrinoless double beta decay is allowed. Apart of one claim that the neutrinoless double beta decay in 76 Ge is measured, one has only upper limits for this transition probability. But even the upper limits allow to give upper limits for the electron Majorana neutrino mass and upper limits for parameters of GUT's and the minimal R-parity violating supersymmetric model. One further can give lower limits for the vector boson mediating mainly the right-handed weak interaction and the heavy mainly right-handed Majorana neutrino in left-right symmetric GUT's. For that one has to assume that the specific mechanism is the leading one for the neutrinoless double beta decay and one has to be able to calculate reliably the corresponding nuclear matrix elements. In the present contribution, one discusses the accuracy of the present status of calculating the nuclear matrix elements and the corresponding limits of GUT's and supersymmetric parameters
An investigation of proton pair correlations relevant to the neutrinoless double beta decay of 76Ge
Ticehurst, David R.
The observation of neutrinoless double beta decay (0nubetabeta ) would demonstrate that the neutrino is a Majorana particle and allow determination of its mass by comparing the measured decay rate to the calculated rate. The main uncertainty in the calculation of the 0 nubetabeta rate is due to uncertainties in the nuclear structure models used in the computation of the nuclear matrix elements for the decay process. This project tested the validity of using wavefunctions for the nuclear states involved in the 0nubetabeta process that are based on a first-order application of the Bardeen-Cooper-Schrieffer (BCS) theory of superconductivity. In the BCS approximation, most of the strength for two-nucleon transfer reactions should be for transitions to the 0 + ground state of the final nucleus (i.e., little strength should go to the 0+ excited states). This experiment measured the strength to the first 0+ excited state for the 74Ge( 3He,n)76Se and 76Ge( 3He,n)78Se reactions relative to the strength for transition to the 0+ ground state in selenium. For both nuclei, and at 3He beam energies of 15 and 21 MeV, the observed relative strength for transfer to the first 0+ excited state was less than 13%. This result supports the validity of using the BCS approximation to describe the ground state of both 76Se and 78Se and is consistent with the results of recent ( 3He,n) cross section measurements on 74Ge and 76Ge. In addition, the magnitude and shape of the measured angular distributions suggest that contribution of the sequential two-nucleon transfer process, which is an indicator of long-range nucleon-nucleon correlations, is over-predicted by the DWBA code FRESCO.
New Technique for Barium Daughter Ion Identification in a Liquid Xe-136 Double Beta Decay Experiment
International Nuclear Information System (INIS)
Fairbank, William
2016-01-01
This work addresses long-standing issues of fundamental interest in elementary particle physics. The most important outcome of this work is a new limit on neutrinoless double beta decay. This is an extremely rare and long-sought-after type of radioactive decay. If discovered, it would require changes in the standard model of the elementary constituents of matter, and would prove that neutrinos and antineutrinos are the same, a revolutionary concept in particle physics. Neutrinos are major components of the matter in the universe that are so small and so weakly interacting with other matter that their masses have not yet been discovered. A discovery of neutrinoless double beta decay could help determine the neutrino masses. An important outcome of the work on this project was the Colorado State University role in operating the EXO-200 neutrinoless double beta decay experiment and in analysis of the data from this experiment. One type of double beta decay of the isotope "1"3"6Xe, the two-neutrino variety, was discovered in this work. Although the other type of double beta decay, the neutrinoless variety, was not yet discovered in this work, a world's best sensitivity of 1.9x10"2"5 year half-life was obtained. This result rules out a previous claim of a positive result in a different isotope. This work also establishes that the masses of the neutrinos are less than one millionth of that of electrons. A unique EXO-200 analysis, in which the CSU group had a leading role, has established for the first time ever in a liquid noble gas the fraction of daughter atoms from alpha and beta decay that are ionized. This result has important impact on other pending studies, including nucleon decay and barium tagging. Novel additional discoveries include multiphoton ionization of liquid xenon with UV pulsed lasers, which may find application in calibration of future noble liquid detectors, and studies of association and dissociation reactions of Ba"+ ions in gaseous xenon. Through
Czech Academy of Sciences Publication Activity Database
Lebeda, Ondřej; Lozza, V.; Petzoldt, J.; Štursa, Jan; Zdychová, Vlasta; Zuber, K.
2014-01-01
Roč. 929, SEP (2014), s. 129-142 ISSN 0375-9474 R&D Projects: GA MŠk(XE) LM2011019 Institutional support: RVO:61389005 Keywords : proton activation * double beta decay * cross-section * production rates * natural neodymium Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 2.202, year: 2014
Cirigliano, V.; Dekens, W.; de Vries, J.; Graesser, M. L.; Mereghetti, E.
2017-12-01
We analyze neutrinoless double beta decay (0 νββ) within the framework of the Standard Model Effective Field Theory. Apart from the dimension-five Weinberg operator, the first contributions appear at dimension seven. We classify the operators and evolve them to the electroweak scale, where we match them to effective dimension-six, -seven, and -nine operators. In the next step, after renormalization group evolution to the QCD scale, we construct the chiral Lagrangian arising from these operators. We develop a power-counting scheme and derive the two-nucleon 0 νββ currents up to leading order in the power counting for each lepton-number-violating operator. We argue that the leading-order contribution to the decay rate depends on a relatively small number of nuclear matrix elements. We test our power counting by comparing nuclear matrix elements obtained by various methods and by different groups. We find that the power counting works well for nuclear matrix elements calculated from a specific method, while, as in the case of light Majorana neutrino exchange, the overall magnitude of the matrix elements can differ by factors of two to three between methods. We calculate the constraints that can be set on dimension-seven lepton-number-violating operators from 0 νββ experiments and study the interplay between dimension-five and -seven operators, discussing how dimension-seven contributions affect the interpretation of 0 νββ in terms of the effective Majorana mass m ββ .
Unexpected strong attraction in the presence of continuum bound state
International Nuclear Information System (INIS)
Delfino, A.; Frederico, T.
1992-06-01
The result of few-particle ground-state calculation employing a two-particle non-local potential supporting a continuum bound state in addition to a negative-energy bound state has occasionally revealed unexpected large attraction in producing a very strongly bound ground state. In the presence of the continuum bound state the difference of phase shift between zero and infinite energies has an extra jump of φ as in the presence of an additional bound state. The wave function of the continuum bound state is identical with that of a strongly bound negative-energy state, which leads us to postulate a pseudo bound state in the two-particle system in order to explain the unexpected attraction. The role of the Pauli forbidden states is expected to be similar to these pseudo states. (author)
2002-01-01
We propose to study the $\\beta$-decay of $^{38}$Ca. In a first instance, we intend to perform a high-precision study of the half-life of this nucleus as well as a measurement of its $\\beta$-decay Q-value with ISOLTRAP. At a later stage, we propose to study its decay branches to determine the super-allowed branching ratio with high precision. These measurements are essential to improve our understanding of the theoretical corrections (in particular the $\\delta$c correction factor) needed to calculate the universal Ft value from the ft value determined for individual nuclei. For this nucleus, the correction factor is predicted to increase significantly as compared to the nine well-studied nuclei between $^{10}$C and $^{54}$Co and the model calculations used to determine the corrections, in particular the shell-model calculations, are well under control in this mass region. Therefore, the T$_{Z}$= -1 nuclei between A=18 and A=38 are ideal test cases for the correction factors which limit today the precision on t...
Charged boson bound states in the kerr-newman metric
International Nuclear Information System (INIS)
Li Yuanjie; Zhang Duanming
1986-01-01
Charged boson bound states in Kerr-Newman metric are discussed. It is found that massless boson cannot be attracted by Kerr-Newman black hole to form bound states. For the massive boson, the condition of the nonbound states when 0 2 - Q 2 and both the condition and wave functions of the bound states when a = √M 2 - Q 2 are obtained. The energy mode of the bound states is single, E = (m√M 2 - Q 2 + eQM)/(2M 2 - Q 2 ). When Q = 0 or e = 0, the conclusion is in agreement with that of Zhang Shiwei and Su Rukeng
Gerda: A new 76Ge Double Beta Decay Experiment at Gran Sasso
International Nuclear Information System (INIS)
Simgen, Hardy
2005-01-01
In the new 76 Ge double beta decay experiment Gerda [I. Abt et al., arXiv hep-ex/0404039; Gerda proposal, to be submitted to the Gran Sasso scientific committee] bare diodes of enriched 76 Ge will be operated in highly pure liquid nitrogen or argon. The goal is to reduce the background around Q ββ =2039 keV below 10 -3 counts/(kg-bar keV-bar y). With presently available diodes from the Igex and HdMs experiments the current evidence for neutrinoless double beta decay [H.-V. Klapdor-Kleingrothaus, et al., Mod. Phys. Lett. A16 (2001) 2409ff] can unambigously be checked within one year of measurement
Determination of the neutrino mass from the beta decay of gaseous molecular tritium
International Nuclear Information System (INIS)
Decman, D.J.; Stoeffl, W.
1992-06-01
We set an upper limit of 8 eV for the mass of the electron antineutrino from studying the beta decay of tritium. We use a gaseous molecular tritium source, a high resolution magnetic spectrometer and a low background counting system to minimize the systematic errors encountered in these measurements. Our calibration data with radioactive 83m Kr enables us to measure our system response function and a good deal of atomic physics data. In addition to our end point results we have made the first measurement of the tritium beta decay spectrum below 200 keV. We find an excess of very low energy electrons which arise from molecular processes of the 3 He-T + ion
The beta(+) decay and cosmic-ray half-life of Mn-54
Dacruz, M. T. F.; Norman, E. B.; Chan, Y. D.; Garcia, A.; Larimer, R. M.; Lesko, K. T.; Stokstad, R. G.; Wietfeldt, F. E.
1993-03-01
We performed a search for the beta(+) branch of Mn-54 decay. As a cosmic ray, Mn-54, deprived of its atomic electrons, can decay only via beta(+) and beta(-) decay, with a half-life of the order of 106 yr. This turns Mn-54 into a suitable cosmic chronometer for the study of cosmic-ray confinement times. We searched for coincident back-to-back 511-keV gamma-rays using two germanium detectors inside a Nal(Tl) annulus. An upper limit of 2 x 10-8 was found for the beta(+) decay branch, corresponding to a lower limit of 13.7 for the log ft value.
Graham, Eleanor; Cuore Collaboration
2017-09-01
The CUORE experiment is a large-scale bolometric detector seeking to observe the never-before-seen process of neutrinoless double beta decay. Predictions for CUORE's sensitivity to neutrinoless double beta decay allow for an understanding of the half-life ranges that the detector can probe, and also to evaluate the relative importance of different detector parameters. Currently, CUORE uses a Bayesian analysis based in BAT, which uses Metropolis-Hastings Markov Chain Monte Carlo, for its sensitivity studies. My work evaluates the viability and potential improvements of switching the Bayesian analysis to Hamiltonian Monte Carlo, realized through the program Stan and its Morpho interface. I demonstrate that the BAT study can be successfully recreated in Stan, and perform a detailed comparison between the results and computation times of the two methods.
The N=82 gap in /sup 146/Gd from beta -decay studies of Tb isotopes
Styczen, J; Kleinheinz, P; Piiparinen, M
1981-01-01
The beta -decay study of 23 s /sup 146/Tb suggests a ( pi h/sub 11/2/ nu d/sup -1//sub 3/2/) 5/sup -/ configuration for this activity. In its decay the authors have identified a pi h/sub 11/2/ to nu h/sub 9/2 / GT decay branch which populates neutron particle-hole states in /sup 146/Gd. Hence the N=82 single particle energy gap is less than 4 MeV. Neutron one-particle two-hole and two-particle one-hole states in /sup 145/Gd and /sup 147/Gd were identified in the beta -decays of 29 s /sup 145/Tb and 1.6 h /sup 147/Tb. (11 refs).
Gross theory of beta-decay and half-lives of short-lived nuclei
International Nuclear Information System (INIS)
Yamada, Masami; Kondo, Norikatsu.
1976-01-01
The gross theory of beta-decay has been developed, and this theory offers the means of calculating directly the function of beta-decay intensity, then half-lives, complex beta spectra and so on are estimated from it. This paper presents the more refined theory by introducing the shell effect. The shell effect is considered in the intensity function. The half-lives in the electron decay of In with spin of 9/2 + , the positron decay of Bi, Po, At and Rn, and the decay of odd-odd nuclei were estimated. The introduction of the shell effect shows better agreement between the theory and the experimental data. The inequality relations of intensity functions and half-lives of two adjacent nuclei were obtained. When the spins and parities of two nuclei are same, the inequality relations hold especially good. (Kato, T.)
Electromagnetically induced nuclear beta decay calculated by a Green's function method
International Nuclear Information System (INIS)
Reiss, H.R.
1984-01-01
The transition probability for enhancement of forbidden nuclear beta decay by an applied plane-wave electromagnetic field is calculated in a nonrelativistic spinless approximation by a Green's function method. The calculation involves a stationary-phase approximation. The stationary phase points in the presence of an intense field are located in very different positions than they are in the field-free case. In order-of-magnitude terms, the results are completely consistent with an earlier, much more complete wave-function calculation which includes spin and relativistic effects. Both the present Green's function calculation and the earlier wave function calculation give electromagnetic contributions in first-forbidden nuclear beta decay matrix elements which are of order (R 0 /lambda-dash-bar/sub C/) 2 with respect to allowed decays, where R 0 is the nuclear radius and lambda-dash-bar/sub C/ is the electron Compton wavelength
Neutrinoless double beta decay with 82SeF6 and direct ion imaging
Nygren, D. R.; Jones, B. J. P.; López-March, N.; Mei, Y.; Psihas, F.; Renner, J.
2018-03-01
We present a new neutrinoless double beta decay concept: the high pressure selenium hexafluoride gas time projection chamber. A promising new detection technique is outlined which combines techniques pioneered in high pressure xenon gas, such as topological discrimination, with the high Q-value afforded by the double beta decay isotope 82Se. The lack of free electrons in SeF6 mandates the use of an ion TPC. The microphysics of ion production and drift, which have many nuances, are explored. Background estimates are presented, suggesting that such a detector may achieve background indices of better than 1 count per ton per year in the region of interest at the 100 kg scale, and still better at the ton-scale.
Signal and background studies for the search of neutrinoless double beta decay in GERDA
International Nuclear Information System (INIS)
Agostini, Matteo
2013-01-01
The GERDA experiment searches for the neutrinoless double beta decay in Ge-76, by operating bare HPGe detectors in ultra-pure liquid Ar. This dissertation presents a first decomposition of the background measured in the current data-taking phase. The background at the energy of interest was found to be dominated by 214 Bi, 208 Tl and 42 K gamma-rays, with secondary contributions from 42 K and 214 Bi beta-rays, and 210 Po alpha-rays. For the forthcoming upgrade of the apparatus, a new HPGe detector design (BEGe) has been studied, with focus on its capability of suppressing the identified backgrounds through pulse shape analysis. This included the development of a comprehensive modeling of the detectors and the experimental characterization of their response to surface interactions. The achieved results show that GERDA can improve the present limit on the neutrinoless double beta decay half-life by an order of magnitude.
Preliminary results from a study of the double beta decay of 150Nd
International Nuclear Information System (INIS)
Perillo, I.M.C.; Chan, Y.D.; Hurley, D.; Lesko, K.T.; McDonald, R.J.; Moorhead, M.E.; Norman, E.B.; Smith, A.R.; Stokstad, R.G.
1996-01-01
We report the preliminary results from a study of the double beta decay of 150 Nd to the first 0 + excited state of 150 Sm. Our data consists of 50 days of counting 5 kg of natural Nd 2 O 3 at the LBNL-Oroville low background facility. The deduced lower limit for the half life of this decay mode is 4.9.10 19 years. (orig.)
Simulation of double beta decay in the 'SeXe' TPC
Energy Technology Data Exchange (ETDEWEB)
Mauger, F [LPC Caen and University of Caen, ENSICAEN, 6 Bd Marechal Juin, 14050 CAEN CEDEX 4 (France)
2007-04-15
In 2004, the NEMO collaboration has started some preliminary studies for a next-generation double beta decay experiment: SuperNEMO. The possibility to use a large gaseous TPC has been investigated using simulation and extrapolation of former experiments. In this talk, I report on the reasons why such techniques have not been selected in 2004 and led the NEMO collaboration to reuse the techniques implemented within the NEMO3 detector.
Simulation of double beta decay in the ''SeXe'' TPC
Mauger, F.
2007-04-01
In 2004, the NEMO collaboration has started some preliminary studies for a next-generation double beta decay experiment: SuperNEMO. The possibility to use a large gaseous TPC has been investigated using simulation and extrapolation of former experiments. In this talk, I report on the reasons why such techniques have not been selected in 2004 and led the NEMO collaboration to reuse the techniques implemented within the NEMO3 detector.
Neutrinoless double beta decay in an SU(3)L x U(1)N model
International Nuclear Information System (INIS)
Pleitez, V.; Tonasse, M.D.
1993-01-01
A model for the electroweak interactions with SU (3) L x U(1) N gauge symmetry is considered. It is shown that, it is the conservation of F = L + B which forbids massive neutrinos and the neutrinoless double beta decay, (β β) On u. Explicit and spontaneous breaking of F imply that the neutrinos have an arbitrary mass and (β β) On u proceeds also with some contributions that do not depend explicitly on the neutrino mass. (author)
The double beta decay spectra of 82Se, 100Mo, and 150Nd
International Nuclear Information System (INIS)
Nelson, M.A.; Moe, M.K.; Vient, M.A.; Elliott, S.R.
1992-01-01
The double beta decay electron energy spectra of 82 Se, 100 Mo, and 150 Nd have been measured with a time projection chamber, and departures from the expected two-neutrino spectral shapes have been observed. Efforts to reduce possible background contamination have been made, and tests are now being done in an effort to determine whether the anomalous signals are real effects, or simply experimental artifacts
International Nuclear Information System (INIS)
Nicholson, H.W.
1996-07-01
This report describes the publication of results of a search for neutrinoless double-beta decay of molybdenum 100 and preparation of a paper on statistical analysis techniques used, developments related to purification techniques for the molybdenum, and other related work; progress in redesign, rebuilding, and installation of the Brookhaven EVA detector's superconducting magnet and cryogenic system; and the testing of detector components for SLAC's BaBar experiment. 3 refs
MaGe: a Monte Carlo framework for the Gerda and Majorana double beta decay experiments
International Nuclear Information System (INIS)
Bauer, M; Belogurov, S; Chan, Yd; Descovich, M; Detwiler, J; Di Marco, M; Fujikawa, B; Franco, D; Gehman, V; Henning, R; Hudek, K; Johnson, R; Jordan, D; Kazkaz, K; Klimenko, A; Knapp, M; Kroeninger, K; Lesko, K; Liu, X; Marino, M; Mokhtarani, A; Pandola, L; Perry, M; Poon, A; Radford, D; Tomei, C; Tull, C
2006-01-01
The Gerda and Majorana projects, both searching for the neutrinoless double beta-decay of 76 Ge, are developing a joint Monte-Carlo simulation framework called MaGe. Such an approach has many benefits: the workload for the development of general tools is shared between more experts, the code is tested in more detail, and more experimental data is made available for validation
Beta decay and other processes in strong electromagnetic fields
International Nuclear Information System (INIS)
Akhmedov, E. Kh.
2011-01-01
We consider effects of the fields of strong electromagnetic waves on various characteristics of quantum processes. After a qualitative discussion of the effects of external fields on the energy spectra and angular distributions of the final-state particles as well as on the total probabilities of the processes (such as decay rates and total cross sections), we present a simple method of calculating the total probabilities of processes with production of nonrelativistic charged particles. Using nuclear β decay as an example, we study the weak- and strong-field limits, as well as the field-induced β decay of nuclei stable in the absence of the external fields, both in the tunneling and multiphoton regimes. We also consider the possibility of accelerating forbidden nuclear β decays by lifting the forbiddeness due to the interaction of the parent or daughter nuclei with the field of a strong electromagnetic wave. It is shown that for currently attainable electromagnetic fields all effects on total β-decay rates are unobservably small.
Double-beta decay investigation with highly pure enriched {sup 82}Se for the LUCIFER experiment
Energy Technology Data Exchange (ETDEWEB)
Beeman, J. W. [Lawrence Berkeley National Laboratory, 94720, Berkeley, CA (United States); Bellini, F. [Dipartimento di Fisica, Sapienza Università di Roma, 00185, Rome (Italy); INFN, Sezione di Roma, 00185, Rome (Italy); Benetti, P. [Dipartimento di Chimica, Università di Pavia, 27100, Pavia (Italy); INFN, Sezione di Pavia, 27100, Pavia (Italy); Cardani, L. [Dipartimento di Fisica, Sapienza Università di Roma, 00185, Rome (Italy); Physics Department, Princeton University, 08544, Princeton, NJ (United States); Casali, N. [Dipartimento di Fisica, Sapienza Università di Roma, 00185, Rome (Italy); INFN, Sezione di Roma, 00185, Rome (Italy)
2015-12-13
The LUCIFER project aims at deploying the first array of enriched scintillating bolometers for the investigation of neutrinoless double-beta decay of {sup 82}Se. The matrix which embeds the source is an array of ZnSe crystals, where enriched {sup 82}Se is used as decay isotope. The radiopurity of the initial components employed for manufacturing crystals, that can be operated as bolometers, is crucial for achieving a null background level in the region of interest for double-beta decay investigations. In this work, we evaluated the radioactive content in 2.5 kg of 96.3 % enriched {sup 82}Se metal, measured with a high-purity germanium detector at the Gran Sasso deep underground laboratory. The limits on internal contaminations of primordial decay chain elements of {sup 232}Th, {sup 238}U and {sup 235}U are respectively: <61, <110 and <74 μBq/kg at 90 % C.L. The extremely low-background conditions in which the measurement was carried out and the high radiopurity of the {sup 82}Se allowed us to establish the most stringent lower limits on the half-lives of the double-beta decay of {sup 82}Se to 0{sub 1}{sup +}, 2{sub 2}{sup +} and 2{sub 1}{sup +} excited states of {sup 82}Kr of 3.4·10{sup 22}, 1.3·10{sup 22} and 1.0·10{sup 22} y, respectively, with a 90 % C.L.
Double-beta decay investigation with highly pure enriched {sup 82}Se for the LUCIFER experiment
Energy Technology Data Exchange (ETDEWEB)
Beeman, J.W. [Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Bellini, F.; Casali, N.; Ferroni, F.; Piperno, G. [Sapienza Universita di Roma, Dipartimento di Fisica, Rome (Italy); INFN, Sezione di Roma, Rome (Italy); Benetti, P. [Universita di Pavia, Dipartimento di Chimica, Pavia (Italy); INFN, Sezione di Pavia, Pavia (Italy); Cardani, L. [Sapienza Universita di Roma, Dipartimento di Fisica, Rome (Italy); Princeton University, Physics Department, Princeton, NJ (United States); Chiesa, D.; Clemenza, M.; Gironi, L.; Maino, M. [Universita di Milano-Bicocca, Dipartimento di Fisica, Milan (Italy); INFN, Sezione di Milano Bicocca, Milan (Italy); Dafinei, I.; Orio, F.; Tomei, C.; Vignati, M. [INFN, Sezione di Roma, Rome (Italy); Di Domizio, S. [INFN, Sezione di Genova, Genoa (Italy); Universita di Genova, Dipartimento di Fisica, Genoa (Italy); Giuliani, A. [Centre de Spectrometrie de Masse, Orsay (France); Gotti, C.; Pessina, G.; Previtali, E.; Rusconi, C. [INFN, Sezione di Milano Bicocca, Milan (Italy); Laubenstein, M.; Nisi, S.; Pattavina, L.; Pirro, S.; Schaeffner, K. [INFN, Laboratori Nazionali del Gran Sasso, Assergi (L' Aquila) (Italy); Nagorny, S.; Pagnanini, L. [Gran Sasso Science Institute, L' Aquila (Italy); Nones, C. [SPP Centre de Saclay, CEA, Irfu, Gif-sur-Yvette (France)
2015-12-15
The LUCIFER project aims at deploying the first array of enriched scintillating bolometers for the investigation of neutrinoless double-beta decay of {sup 82}Se. The matrix which embeds the source is an array of ZnSe crystals, where enriched {sup 82}Se is used as decay isotope. The radiopurity of the initial components employed for manufacturing crystals, that can be operated as bolometers, is crucial for achieving a null background level in the region of interest for double-beta decay investigations. In this work, we evaluated the radioactive content in 2.5 kg of 96.3 % enriched {sup 82}Se metal, measured with a high-purity germanium detector at the Gran Sasso deep underground laboratory. The limits on internal contaminations of primordial decay chain elements of {sup 232}Th, {sup 238}U and {sup 235}U are respectively: <61, <110 and <74 μBq/kg at 90 % C.L. The extremely low-background conditions in which the measurement was carried out and the high radiopurity of the {sup 82}Se allowed us to establish the most stringent lower limits on the half-lives of the double-beta decay of {sup 82}Se to 0{sub 1}{sup +}, 2{sub 2}{sup +} and 2{sub 1}{sup +} excited states of {sup 82}Kr of 3.4.10{sup 22}, 1.3.10{sup 22} and 1.0.10{sup 22} y, respectively, with a 90 % C.L. (orig.)
Possible test of grand unification in the double beta-decay
International Nuclear Information System (INIS)
Faessler, A.
1988-01-01
The more successful grand unified theories predict that the neutrino is identical with its antiparticle and therefore is a Majorana neutrino which violates lepton number conservation. Such a neutrino should have a finite mass and also a small right handed weak interaction. If the double neutrinoless beta decay is observed with the full decay energy in the two electrons, it would establish that the electron neutrino is a Majorana particle. It is shown that the relativistic corrections of the nucleonic wave functions are essential for determining an upper limit of the right handedness from the measured lower limit of the life-time against the neutrinoless double beta decay. The upper limit for the right handedness of the weak interaction derived from the lower limit of the life-times against the neutrinoless beta decay is vertical stroke vertical stroke -8 and the upper limit for the neutrino mass is vertical stroke ν m>vertical stroke + -decay in proton rich nuclei, one can explain the long standing puzzle of the quenching of the Gamow-Teller strength in agreement with the data. (orig.)
Scalar-mediated double beta decay and LHC
Energy Technology Data Exchange (ETDEWEB)
Gonzalez, L. [Universidad Técnica Federico Santa María, Centro-Científico-Tecnológico de Valparaíso,Casilla 110-V, Valparaíso (Chile); Helo, J.C. [Universidad Técnica Federico Santa María, Centro-Científico-Tecnológico de Valparaíso,Casilla 110-V, Valparaíso (Chile); Departamento de Física, Facultad de Ciencias, Universidad de La Serena,Avenida Cisternas 1200, La Serena (Chile); Hirsch, M. [AHEP Group, Instituto de Física Corpuscular - C.S.I.C./Universitat de València,Edificio de Institutos de Paterna, Apartado 22085, E-46071 València (Spain); Kovalenko, S.G. [Universidad Técnica Federico Santa María, Centro-Científico-Tecnológico de Valparaíso,Casilla 110-V, Valparaíso (Chile)
2016-12-23
The decay rate of neutrinoless double beta (0νββ) decay could be dominated by Lepton Number Violating (LNV) short-range diagrams involving only heavy scalar intermediate particles, known as “topology-II” diagrams. Examples are diagrams with diquarks, leptoquarks or charged scalars. Here, we compare the LNV discovery potentials of the LHC and 0νββ-decay experiments, resorting to three example models, which cover the range of the optimistic-pessimistic cases for 0νββ decay. We use the LHC constraints from dijet as well as leptoquark searches and find that already with 20/fb the LHC will test interesting parts of the parameter space of these models, not excluded by the current limits on 0νββ-decay.
Scalar-mediated double beta decay and LHC
International Nuclear Information System (INIS)
Gonzalez, L.; Helo, J.C.; Hirsch, M.; Kovalenko, S.G.
2016-01-01
The decay rate of neutrinoless double beta (0νββ) decay could be dominated by Lepton Number Violating (LNV) short-range diagrams involving only heavy scalar intermediate particles, known as “topology-II” diagrams. Examples are diagrams with diquarks, leptoquarks or charged scalars. Here, we compare the LNV discovery potentials of the LHC and 0νββ-decay experiments, resorting to three example models, which cover the range of the optimistic-pessimistic cases for 0νββ decay. We use the LHC constraints from dijet as well as leptoquark searches and find that already with 20/fb the LHC will test interesting parts of the parameter space of these models, not excluded by the current limits on 0νββ-decay.
Status of the Los Alamos tritium beta decay experiment
International Nuclear Information System (INIS)
Robertson, R.G.H.; Bowles, T.J.; Wark, D.L.; Wilkerson, J.F.; Knapp, D.A.
1989-01-01
The Los Alamos tritium experiment employs a gaseous tritium source and a magnetic spectrometer to determine the mass of the electron antineutrino from the shape of the tritium beta spectrum. Since publication of the first result from this apparatus (m/sub nu/ < 27 eV at 95% confidence), work has concentrated on improving the data rates. A 96-element Si microstrip array detector has been installed to replace the single proportional counter at the spectrometer focus, resulting in greatly increased efficiency. Measurements of the 1s photoionization spectrum of Kr now obviate the need for reliance on the theoretical shakeup and shakeoff spectrum of Kr in determining the spectrometer resolution. 19 refs., 3 figs
Double beta decay: Comparison of theory to experiment
International Nuclear Information System (INIS)
Haxton, W.C.
1992-01-01
I review ββ decay in the standard model and as a test of Majorana neutrino masses and right-handed couplings. A summary is given of some of the nuclear physics issues involved in evaluating 2 ν and 0ν matrix elements. Dirac and pseudoDirac limits are discussed to illustrate how quantities constrained on 0ν ββ decay depend on the parameters of the mass matrix. Implications of 0ν ββ decay for models with 17 keV neutrinos, for models with massive Majorana neutrinos, and for Majorons are discussed. It is argued that a recent remeasurement of the total ββ decay rate of 126 Te is important in constraining (nonstandard) Majoron models
Dark-matter bound states from Feynman diagrams
Petraki, K.; Postma, M.; Wiechers, M.
2015-01-01
If dark matter couples directly to a light force mediator, then it may form bound states in the early universe and in the non-relativistic environment of haloes today. In this work, we establish a field-theoretic framework for the computation of bound-state formation cross-sections, de-excitation
Proximity effect tunneling into virtual bound state alloys
International Nuclear Information System (INIS)
Tang, I.M.; Roongkkeadsakoon, S.
1984-01-01
The effects of a narrow virtual bound state formed by transition metal impurities dissolved in the normal layer of a superconducting proximity effect sandwich are studied. Using standard renormalization techniques, we obtain the changes in the transition temperatures and the jumps in the specific heat at T/sub c/ as a function of the thickness of the normal layer, of the widths of the virtual bound states, and of the impurity concentrations. It is seen that narrow virtual bound states lead to decrease in the transition temperatures, while broad virtual bound states do not. It if further seen that the narrow virtual bound state causes the reduced specific heat jump at T/sub c/ to deviate from the BCS behavior expected of the pure sandwich
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 ^{136}Xe, the two-neutrino variety, was discovered in this work. Although the other type of double beta decay, the neutrinoless variety, was not yet discovered in this work, a world’s best sensitivity of 1.9x10^{25} 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
The Search for Neutrinoless Double Beta Decay with 130Te with CUORE-0
International Nuclear Information System (INIS)
Ouellet, Jonathan Loren
2015-01-01
This thesis describes the design, operation and results of an experimental search for neutrinoless double beta decay (0νββ) of 130 Te using the CUORE-0 detector. The discovery of 0νββ would have profound implications for particle physics and our understanding of the Universe. Its discovery would demonstrate the violation of lepton number and imply that neutrinos are Majorana fermions and therefore their own anti-particles. Combined with other experimental results, the discovery of 0νββ could also have implications for understanding the absolute neutrino mass scale as well as the presently unknown neutrino mass hierarchy. The CUORE experiment is a ton-scale search for 0νββ in 130 Te expected to begin operation in late 2015. The first stage of this experiment is a smaller 39-kg active-mass detector called CUORE-0. This detector contains 11 kg of 130 Te and operates in the Laboratori Nazionali del Gran Sasso lab in Italy from 2013-2015. The results presented here are based on a nat TeO 2 exposure of 35.2 kg·yr, or 9.8 kg·yr exposure of 130 Te collected between 2013-2015. We see no evidence of 0νββ and place an upper limit on the 0νββ decay rate of Γ 0νββ <0.25x10 24 yr 1 (90 % C.L.), corresponding to a lower limit on the half-life of T 1/2 0ν >2.8x10 24 yr (90 % C.L.). We combine the present result with the results of previous searches in 130 Te. Combining it with the 1.2 kg·Te exposure from the Three Towers Test run we place a half-life limit of T 1/2 03 ν>3.3x10 24 yr (90 % C.L.). And combining these results with the 19.75 kg·yr 130 Te exposure from Cuoricino, we place the strongest limit on the 0νββ half-life of 130 Te to date, at T 1/2 0ν >4.5x10 24 yr (90 % C.L.). Using the present nuclear matrix element calculations for 130 Te, this result corresponds to a 90 % upper limit range on the effective Majorana mass of m ββ <250-710 meV.
Two-phonon bound states in imperfect crystals
International Nuclear Information System (INIS)
Behera, S.N.; Samsur, Sk.
1980-01-01
The question of the occurrence of two-phonon bound states in imperfect crystals is investigated. It is shown that the anharmonicity mediated two-phonon bound state which is present in perfect crystals gets modified due to the presence of impurities. Moreover, the possibility of the occurrence of a purely impurity mediated two-phonon bound state is demonstrated. The bound state frequencies are calculated using the simple Einstein oscillator model for the host phonons. The two-phonon density of states for the imperfect crystal thus obtained has peaks at the combination and difference frequencies of two host phonons besides the peaks at the bound state frequencies. For a perfect crystal the theory predicts a single peak at the two-phonon bound state frequency in conformity with experimental observations and other theoretical calculations. Experimental data on the two-phonon infrared absorption and Raman scattering from mixed crystals of Gasub(1-c)Alsub(c)P and Gesub(1-c)Sisub(c) are analysed to provide evidence in support of impurity-mediated two-phonon bound states. The relevance of the zero frequency (difference spectrum) peak to the central peak, observed in structural phase transitions, is conjectured. (author)
Nuclear beta decay induced by intense electromagnetic fields: Forbidden transition examples
International Nuclear Information System (INIS)
Reiss, H.R.
1983-01-01
A formalism developed earlier for the effect on nuclear beta decay of an intense plane-wave electromagnetic field is applied to three examples of forbidden beta transitions. The examples represent cases where the nuclear ''fragment'' contains one, two, and three nucleons; where the nuclear fragment is defined to be that smallest sub-unit of the nucleus containing the nucleon which undergoes beta decay plus any other nucleons directly angular-momentum coupled to it in initial or final states. The single-nucleon-fragment example is 113 Cd, which has a fourth-forbidden transition. The two-nucleon-fragment example is 90 Sr, which is first-forbidden. The three-nucleon-fragment example is 87 Rb, which is third-forbidden. An algebraic closed-form transition probability is found in each case. At low external-field intensity, the transition probability is proportional to z/sup L/, where z is the field intensity parameter and L is the degree of forbiddenness. At intermediate intensities, the transition probability behaves as z/sup L/-(1/2). At higher intensities, the transition probability contains the z/sup L/-(1/2) factor, a declining exponential factor, and an alternating polynomial in z. This high-intensity transition probability possesses a maximum value, which is found for each of the examples. A general rule, z = q 2 (2L-1), where q is the number of particles in the fragment, is found for giving an upper limit on the intensity at which the maximum transition probability occurs. Field-induced beta decay half-lives for all the examples are dramatically reduced from natural half-lives when evaluated at the optimum field intensity. Relative half-life reduction is greater the higher the degree of forbiddenness
Combining and comparing neutrinoless double beta decay experiments using different nuclei
Bergström, Johannes
2013-02-01
We perform a global fit of the most relevant neutrinoless double beta decay experiments within the standard model with massive Majorana neutrinos. Using Bayesian inference makes it possible to take into account the theoretical uncertainties on the nuclear matrix elements in a fully consistent way. First, we analyze the data used to claim the observation of neutrinoless double beta decay in 76Ge, and find strong evidence (according to Jeffrey's scale) for a peak in the spectrum and moderate evidence for that the peak is actually close to the energy expected for the neutrinoless decay. We also find a significantly larger statistical error than the original analysis, which we include in the comparison with other data. Then, we statistically test the consistency between this claim with that of recent measurements using 136Xe. We find that the two data sets are about 40 to 80 times more probable under the assumption that they are inconsistent, depending on the nuclear matrix element uncertainties and the prior on the smallest neutrino mass. Hence, there is moderate to strong evidence of incompatibility, and for equal prior probabilities the posterior probability of compatibility is between 1.3% and 2.5%. If one, despite such evidence for incompatibility, combines the two data sets, we find that the total evidence of neutrinoless double beta decay is negligible. If one ignores the claim, there is weak evidence against the existence of the decay. We also perform approximate frequentist tests of compatibility for fixed ratios of the nuclear matrix elements, as well as of the no signal hypothesis. Generalization to other sets of experiments as well as other mechanisms mediating the decay is possible.
Ice shielding in the large scale GENIUS experiment for double beta decay and dark matter search
International Nuclear Information System (INIS)
Klapdor-Kleingrothaus, H.V.; Zdesenko, Yu.G.
1998-01-01
We suggest here the use of ice as shielding material in the large scale GENIUS experiment for the ultimate sensitive double beta decay and dark matter search. The idea is to pack a working volume of several tons of liquid nitrogen, which contains the ''naked'' Ge detectors, inside an ice shielding. Very thin plastic foil would be used in order to prevent leakage of the liquid nitrogen. Due to the excellent advantages of ice shielding (high purity and low cost, self-supporting ability, thermo-isolation and optical properties, safety) this could be another possible way of realization of the GENIUS project. (orig.)
Limit on Neutrinoless Double Beta Decay of 76Ge by GERDA
Agostini, M.; Allardt, M.; Andreotti, E.; Bakalyarov, A. M.; Balata, M.; Barabanov, I.; Heider, M. Barabè; Barros, N.; Baudis, L.; Bauer, C.; Becerici-Schmidt, N.; Bellotti, E.; Belogurov, S.; Belyaev, S. T.; Benato, G.; Bettini, A.; Bezrukov, L.; Bode, T.; Brudanin, V.; Brugnera, R.; Budjáš, D.; Caldwell, A.; Cattadori, C.; Chernogorov, A.; Cossavella, F.; Demidova, E. V.; Domula, A.; Egorov, V.; Falkenstein, R.; Ferella, A.; Freund, K.; Frodyma, N.; Gangapshev, A.; Garfagnini, A.; Gotti, C.; Grabmayr, P.; Gurentsov, V.; Gusev, K.; Guthikonda, K. K.; Hampel, W.; Hegai, A.; Heisel, M.; Hemmer, S.; Heusser, G.; Hofmann, W.; Hult, M.; Inzhechik, L. V.; Csáthy, J. Janicskó; Jochum, J.; Junker, M.; Kihm, T.; Kirpichnikov, I. V.; Kirsch, A.; Klimenko, A.; Knöpfle, K. T.; Kochetov, O.; Kornoukhov, V. N.; Kuzminov, V. V.; Laubenstein, M.; Lazzaro, A.; Lebedev, V. I.; Lehnert, B.; Liao, H. Y.; Lindner, M.; Lippi, I.; Lubashevskiy, A.; Lubsandorzhiev, B.; Lutter, G.; Machado, A. A.; Macolino, C.; Majorovits, B.; Maneschg, W.; Misiaszek, M.; Nemchenok, I.; Nisi, S.; Shaughnessy, C. O.'.; Pandola, L.; Pelczar, K.; Pessina, G.; Pullia, A.; Riboldi, S.; Rumyantseva, N.; Sada, C.; Salathe, M.; Schmitt, C.; Schreiner, J.; Schulz, O.; Schwingenheuer, B.; Schönert, S.; Shevchik, E.; Shirchenko, M.; Simgen, H.; Smolnikov, A.; Stanco, L.; Strecker, H.; Tarka, M.; Ur, C. A.; Vasenko, A. A.; Volynets, O.; von Sturm, K.; Wagner, V.; Walter, M.; Wegmann, A.; Wester, T.; Wojcik, M.; Yanovich, E.; Zavarise, P.; Zhitnikov, I.; Zhukov, S. V.; Zinatulina, D.; Zuber, K.; Zuzel, G.
The Gerda experiment at the Laboratori Nazionali del Gran Sasso in Italy uses germanium detectors made from material with an enriched 76Ge isotope fraction to search for neutrinoless double beta decay of this nucleus. Applying a blind analysis we find no signal after an exposure of 21.6 kg·yr and a background of about 0.01 cts/(keV·kg·yr). A half-life limit of Tov1/2> 2.1 · 1025 yr (90% C.L.) is extracted. The previous claim of a signal for 76Ge is excluded with 99% probability in a model independent way.
The Milano-Gran Sasso double beta decay experiment: toward a 20-crystal array
International Nuclear Information System (INIS)
Alessandrello, A.; Brofferio, C.; Bucci, C.; Cremonesi, O.; Fiorini, E.; Giuliani, A.; Nucciotti, A.; Pavan, M.; Pessina, G.; Previtali, E.; Zanotti, L.
1996-01-01
TeO 2 thermal detectors are being used by the Milano group to search for neutrinoless double beta decay of 130 Te. An upper limit for neutrinoless decay half life of 2.1 x 10 22 yr at 90% CL obtained with a 334 g TeO 2 detector has been previously reported. To improve the sensitivity of the experiment an array of twenty 340 g TeO 2 crystals will be realised in the next future. As a first step toward the realisation of that experiment a 4 crystal detector has been tested in the Gran Sasso refrigerator. Detector performances, data acquisition and analysis are discussed. (orig.)
Simulation of complex detection systems in neutrinoless double beta decay experiments
International Nuclear Information System (INIS)
Larrea, A.; Morales, A.; Morales, J.; Nunez-Lagos, R.; Puimedon, J.; Villar, J.A.
1988-01-01
The estimated efficiency of several detection systems dedicated to the search of the neutrinoless double beta decay of 76 Ge is reported. In order to perform this work, we have developed the GEOM macro library system which can handle highly complex geometries in simulation problems, allowing to include an accurate description of the experimental setup in a very simple way. Also an internal mechanism for checking the correct location of every boundary defining the geometrical regions is included. The present version of GEOM is implemented in the EGS4 code of Monte Carlo simulation of photons and electron/positron showers, but it can be easily extended to other simulation codes. (orig.)
Study of the deuteron emission in the $\\beta$-decay of $^{6}$He
Karny, M; Tengblad, O; Riisager, K; Perkowski, J; Garcia borge, M J; Raabe, R; Kowalska, M; Fynbo, H O U; Perea martinez, A; Ter-akopian, G; Huyse, M L
The main goal of the present proposal is to measure the continuous spectrum of deuterons emitted in the $\\beta$-decay of $^{6}$He. In particular, we want to focus on the low energy part of the spectrum, below 400 keV, which could not be accessed by all previous experiments. For the decay spectroscopy the Warsaw Optical Time Projection Chamber (OTPC) will be used. The bunches of $^{6}$He ions produced by REX-ISOLDE facility will be implanted into the active volume of the OTPC, where the rare events of deuteron emission will be recorded, practically background free.
The double beta decay spectrum of 100Mo as measured with a TPC
International Nuclear Information System (INIS)
Elliott, S.R.; Moe, M.K.; Nelson, M.A.; Vient, M.A.
1991-01-01
A time projection chamber with 8.3 grams of enriched 100 MoO 3 as the central electrode has been operating approximately five months in an underground laboratory. A preliminary analysis of the two-electron sum energy spectrum, the spectrum of those same electrons taken singly, and the opening angle distribution yields a half life of 1.16 -0.08 +0.34 x10 19 y at the 68% confidence level for two-neutrino double beta decay of 100 Mo. (author)
Neutrinoless double-beta decay search with CUORE and CUORE-0 experiments
Directory of Open Access Journals (Sweden)
Moggi N.
2015-01-01
Full Text Available The Cryogenic Underground Observatory for Rare Events (CUORE is an upcoming experiment designed to search for the neutrinoless double-beta decays. Observation of the process would unambiguously establish that neutrinos are Majorana particles and provide information on their absolute mass scale hierarchy. CUORE is now under construction and will consist of an array of 988 TeO2 crystal bolometers operated at 10 mK, but the first tower (CUORE-0 is already taking data. The experimental techniques used will be presented as well as the preliminary CUORE-0 results. The current status of the full-mass experiment and its expected sensitivity will then be discussed.
Monte Carlo Simulation for the Majorana Neutrinoless Double-beta Decay Experiment
International Nuclear Information System (INIS)
Henning, Reyco; Majorana Collaboration
2005-01-01
The Majorana experiment is a proposed HPGe detector array that will primarily search for neutrinoless double-beta decay and dark matter. It will rely on pulse-shape discrimination and crystal segmentation to suppress backgrounds following careful materials selection. A critical aspect of the design phase of Majorana is a reliable simulation of the detector response, pulse formation, and its radioactive backgrounds. We are developing an adaptable and complete simulation based on GEANT 4 to address these requirements and the requirements of a modern, large collaboration experiment. The salient aspects of the simulation are presented. The Majorana experiment is presented in a parallel poster by Kareem Kazkaz
Neutrinoless double beta decay search for 130Te: cuoricino status and cuore prospects
International Nuclear Information System (INIS)
Sangiorgio, S.; Artusa, D.R.; And others
2006-01-01
CUORE is a ∼ I-ton experiment to search for Neutrinoless Double Beta Decay of 130 Te using 988 TeO 2 bolometers. It aims at reaching a sensitivity of the order of few tens of MeV on the effective neutrino mass. CUORICINO, a single CUORE tower running since 2003 in the Gran Sasso Underground Laboratory (LNGS), plays an important role as a standing alone experiment and for developing the future CUORE setup. Present results already achieved and studies that are underway are presented and discussed
International Nuclear Information System (INIS)
Arima, A.; Hyuga, H.
1979-01-01
The authors review systematically several important mechanisms which affect magnetic moments, magnetic dipole transitions and allowed beta-decays. They are first order configuration mixing, second order configuration mixing, the Sachs moment and other exchange magnetic moments, the contribution of the Sachs moment and other exchange magnetic moments with first order configuration mixing. It is shown that first order configuration mixing and the Sachs moment are important for heavy nuclei, and that all the effects except first order mixing are important for light nuclei. (Auth.)
Study of multi-neutron emission in the $\\beta$-decay of $^{11}$Li
A new investigation of neutron emission in the $\\beta$-decay of $^{11}$Li is proposed. The principal goal of this study will be to directly measure, for the first time for any system, two $\\beta$-delayed neutrons in coincidence and determine the energy and angular correlations. This will be possible using liquid scintillator detectors, capable of distinguishing between neutrons and ambient $\\gamma$ and cosmic-rays, coupled to a new digital electronics and acquisition system. In parallel, a considerably more refined picture of the single-neutron emission will be obtained.
The beta-decay of 48Mn: improved data on Gamow-Teller quenching
International Nuclear Information System (INIS)
Szerypo, J.; Bazin, D.; Brown, B.A.
1991-01-01
Beta-decay studies of very proton-rich nuclides allow to investigate the phenomenon of quenching of Gamow-Teller transitions. A presentation of the experimental techniques is followed by the discussion of preliminray results of the measurements in comparison to shell-model calculations. A corresponding reinvestigation is discussed. A mass-separated 48 Mn beam was used from 12 C( 40 Ca,p3n) reactions. The 48 Mn decay spectroscopy was performed simultaneously in two beam lines of the mass separator. (G.P.) 13 refs.; 2 figs
New information on the $\\beta$-decay of $^{11}$Li from Doppler broadened $\\gamma$-lines
Fynbo, H O U; Cederkäll, J; Courtin, S; Dessagne, P; Jonson, B; Le Scornet, G; Nilsson, T; Nyman, G H; Poirier, E; Riisager, K; Tengblad, O; Wilhelmsen, K
2004-01-01
The $\\gamma$-ray spectrum following $\\beta$-decay of $^{11}$Li has been remeasured at the ISOLDE facility at CERN. Two new transitions were observed through the use of large Ge-detectors. Most $\\gamma$-decays will follow P-delayed neutron emission. Information on the energy of the neutron is derived from analysis of the $\\gamma$-line-shape and used to construct a partial decay scheme for $^{11}$Li. Lifetime values for the 1$^{-}$ and 2$^{-}$ levels in $^{10}$Be are also derived. A new partial decay scheme is presented. (43 refs).
Deformation of the N=Z nucleus $^{76}$Sr using $\\beta$-decay studies
Nacher, E; Rubio, B; Taín, J L; Cano-Ott, D; Courtin, S; Dessagne, P; Maréchal, F; Miehé, C; Poirier, E; García-Borge, M J; Escrig, D; Jungclaus, A; Sarriguren, P; Tengblad, O; Gelletly, W; Fraile-Prieto, L M; Le Scornet, G; Dessagne, Ph.; Miehe, Ch.
2004-01-01
A novel method of deducing the deformation of the N=Z nucleus $^{76}$Sr is presented. It is based on the comparison of the experimental Gamow-Teller strength distribution B(GT) from its $\\beta$-decay with the results of QRPA calculations. This method confirms previous indications of the strong prolate deformation of this nucleus in a totally independent and novel way. The measurement has been carried out with a large Total Absorption Gamma Spectrometer, "Lucrecia", newly installed at CERN-ISOLDE.
Beta-decay half-lives at the N=28 shell closure
Energy Technology Data Exchange (ETDEWEB)
Grevy, S.; Angelique, J.C.; Baumann, P.; Borcea, C.; Buta, A.; Canchel, G.; Catford, W.N.; Courtin, S.; Daugas, J.M.; Oliveira, F. de; Dessagne, P.; Dlouhy, Z.; Knipper, A.; Kratz, K.L.; Lecolley, F.R.; Lecouey, J.L.; Lehrsenneau, G.; Lewitowicz, M.; Lienard, E.; Lukyanov, S.; Marechal, F.; Miehe, C.; Mrazek, J.; Negoita, F.; Orr, N.A.; Pantelica, D.; Penionzhkevich, Y.; Peter, J.; Pfeiffer, B.; Pietri, S.; Poirier, E.; Sorlin, O.; Stanoiu, M.; Stefan, I.; Stodel, C.; Timis, C
2004-08-05
Measurements of the beta-decay half-lives of neutron-rich nuclei (Mg-Ar) in the vicinity of the N=28 shell closure are reported. Some 22 half-lives have been determined, 12 of which for the first time. Particular emphasis is placed on the results for the Si isotopes, the half-lives of which have been extended from N=25 to 28. Comparison with QRPA calculations suggests that {sup 42}Si is strongly deformed. This is discussed in the light of a possible weakening of the spin-orbit potential.
Beta-decay strength and isospin mixing studies in the sd and fp-shells
International Nuclear Information System (INIS)
Jokinen, A.; Aeystoe, J.; Dendooven, P.; Honkanen, A.; Lipas, P.; Peraejaervi, K.; Oinonen, M.; Siiskonen, T.
1998-01-01
We have studied beta decays of M T 41 Ti shows a large, 10(8) %, isospin mixing of IAS and the Gamow-Teller strength is observed to be quenched by a factor of q 2 =0.64. These results can be reproduced qualitatively in our shell model calculations. We have observed for the first time proton and gamma decay of the isobaric analogue state in 23 Mg. Our results on the isospin mixing of the isobaric analogue state agrees well with the shell model calculations. The obtained proton branch of the IAS is used to extract the transition strength for the reaction 22 Na(p,γ) 23 Mg
Structure of $^{191}$Pb from $\\alpha$- and $\\beta$-decay spectroscopy
Cocolios, T E; Van de Walle, J; Franchoo, S; Marsh, B A; Sjoedin, A M; Huyse, M; Zemlyanoy, S; Cocolios, T E; Bastin, B; Barzakh, A; Page, R D; Mane, E; Van Duppen, P; Darby, I G; Venhart, M; Kudryavtsev, Yu; Huber, G; Fedosseev, V N; Andreyev, A N; Keupers, M; Flanagan, K T; Stefan, I; Dexters, W; Koester, U; Antalic, S; Buscher, J; Molkanov, P; Fedorov, D V
2010-01-01
Complementary studies of $^{191}$Pb have been made in the $\\beta$- decay of $^{191}$Bi at LISOL (CRC) and in the $\\alpha$- decay of $^{195}$Po at ISOLDE (CERN). Fine structures in the $\\alpha$- decay of the low-spin and high-spin isomers of $^{195}$Po have been fully resolved. Identification of the parent state is made possible via isomer selection based on narrow-band laser frequency scanning. The $\\alpha$-particle and $\\gamma$-ray energies have been determined with greater precision. New $\\alpha$-particle and $\\gamma$-ray energies are identified. Branching ratios in the decay of $^{195}$Po and $^{191}$Pb have been examined.
Exchange interaction in scattering on the bound state
International Nuclear Information System (INIS)
Arkhipov, A.A.; Savrin, V.I.
1975-01-01
In the framework of the one-time formulation of three-body problem in quantum field theory, the problem of scattering on the bound state is considered for the case when one of the incident particles is identical to one of the particles of the target. It is shown that due to the identical nature of these particles the exchange interaction takes place which can be connected with the mechanism of scattering on the bound state with the rearrangement
International Nuclear Information System (INIS)
Turkevich, A.; Economou, T.E.
1993-01-01
This report is in two parts. The first part reports on the experimental work determining the half-life for double beta decay of 238 U to 238 PU to be (2.0 ± 0.6) x 10 21 years. This is the first evidence for a third mode of decay of this heaviest naturally occurring nucleus. This rate is about 10 6 times slower than spontaneous fission, which itself is about 10 6 times slower than alpha decay. The implication of this double beta decay to neutrino masses depends on uncertain theoretical calculations of the rate for such a heavy nucleus. The second part reports on yields of principal fission products from 5.6, 7.3, 9.4, and 11.5 MeV proton interactions with 238 U. The yields at 11.5 MeV are similar to those from 14 MeV neutron fission of 238 U. At the same time, the production cross sections of 238 Np at the same energies are determined. This nuclide is produced as often as fission at the lowest energy but only 3.8% as often at the highest energy
Future perspectives of double beta decay and dark matter search - GENIUS
International Nuclear Information System (INIS)
Klapdor-Kleingrothaus, H.V.; Hellmig, J.; Hirsch, M.
1998-01-01
The recent results from the HEIDELBERG-MOSCOW experiment have demonstrated the large potential of double beta decay to search for new physics beyond the standard model. To increase by a major step the present sensitivity for double beta decay and dark matter search, much bigger source strengths and much lower backgrounds are needed than used in experiments under operation at present or under construction. We describe here a project which would operate one tonne of 'naked' enriched germanium-detectors in liquid nitrogen as shielding in an underground set-up (GENIUS). It improves the sensitivity of neutrino masses to 0.01 eV. A 10 tonne version would probe neutrino masses even down to 10 -3 eV. The first version would allow us to test the atmospheric neutrino problem, the second at least part of the solar neutrino problem. Both versions would allow, in addition, significant contributions to testing several classes of GUT models. These are especially tests of R-parity breaking and conserving supersymmetry models - including sneutrino masses - leptoquark masses and mechanism and right-handed W-boson masses comparable with LHC. The second issue of the experiment is the search for dark matter in the universe. The full MSSM parameter space for the prediction of neutralinos as dark matter particles could be covered already in a first step of the full experiment using only 100 kg of 76 Ge or even of natural Ge making the experiment competitive with LHC in the search for supersymmetry. (author)
Status of evidence for neutrinoless double beta decay, and the future. Genius and genius-TF
International Nuclear Information System (INIS)
Klapdor-Kleingrothaus, H.V.
2004-01-01
The first evidence for neutrinoless double beta decay has been observed in the HEIDELBERG-MOSCOW experiment, which is the most sensitive double beta decay experiment since ten years. This is the first evidence for lepton number violation and proves that the neutrino is a Majorana particle. It further shows that neutrino masses are degenerate. In addition it puts several stringent constraints on other physics beyond the Standard Model. The result from the HEIDEL-BERG-MOSCOW experiment is consistent with recent results from CMB investigations, with high energy cosmic rays, with the result from the g-2 experiment and with recent theoretical work. It is indirectly supported by the analysis of other Ge double beta experiments. The new project GENIUS will cover a wide range of the parameter space of predictions of SUSY for neutralinos as cold dark matter. Further it has the potential to be a real-time detector for low-energy (pp and 7 Be) solar neutrinos. A GENIUS Test Facility has come into operation on May 5, 2003. This is the first time that this novel technique for extreme background reduction in search for rare decays is applied under the background conditions of an underground laboratory. (author)
Signal and background studies for the search of neutrinoless double beta decay in GERDA
Energy Technology Data Exchange (ETDEWEB)
Agostini, Matteo
2013-04-24
The GERDA experiment searches for the neutrinoless double beta decay in Ge-76, by operating bare HPGe detectors in ultra-pure liquid Ar. This dissertation presents a first decomposition of the background measured in the current data-taking phase. The background at the energy of interest was found to be dominated by {sup 214}Bi, {sup 208}Tl and {sup 42}K gamma-rays, with secondary contributions from {sup 42}K and {sup 214}Bi beta-rays, and {sup 210}Po alpha-rays. For the forthcoming upgrade of the apparatus, a new HPGe detector design (BEGe) has been studied, with focus on its capability of suppressing the identified backgrounds through pulse shape analysis. This included the development of a comprehensive modeling of the detectors and the experimental characterization of their response to surface interactions. The achieved results show that GERDA can improve the present limit on the neutrinoless double beta decay half-life by an order of magnitude.
Search for neutrinoless double beta decay of Ge-76 with the GERmanium Detector Array '' GERDA ''
International Nuclear Information System (INIS)
Brugnera, R.
2009-01-01
The study of neutrinoless double beta decay (DBD) is the most powerful approach to the fundamental question if the neutrino is a Majorana particle, i.e. its own anti-particle. The observation of neutrinoless DBD would not only establish the Majorana nature of the neutrino but also represent a determination of its effective mass if the nuclear matrix element is given. So far, the most sensitive results have been obtained with Ge-76, and the group of Klapdor-Kleingrothaus has made a claim of discovery. Future experiments have to reduce radioactive backgrounds to increase the sensitivity. '' GERDA '' is a new double beta-decay experiment which is currently under construction in the INFN Gran Sasso National Laboratory, Italy. It is implementing a new shielding concept by operating bare Ge diodes - enriched in Ge-76 - in high purity liquid argon supplemented by a water shield. The aim of '' GERDA '' is to verify or refute the recent claim of discovery, and, in a second phase, to achieve a two orders of magnitude lower background index than recent experiments, increasing the sensitive mass and reaching exposure of 100 kg yr. It be will discuss design, physics reach, and status of construction of '' GERDA '', and present results from various R efforts including long term stability of bare Ge diodes in cryogenic liquids, material screening, cryostat performance, detector segmentation, cryogenic precision electronics, safety aspects, and Monte Carlo simulations. (author)
GERDA and the search for neutrinoless double beta decay: first results and perspectives
Energy Technology Data Exchange (ETDEWEB)
Agostini, Matteo [Physik Department and Excellence Cluster Universe, Technische Universitaet Muenchen (Germany); Collaboration: GERDA-Collaboration
2014-07-01
Neutrinoless double beta decay is a lepton-number-violating nuclear transition predicted by several extensions of the Standard Model. The Gerda experiment searches for this transition in {sup 76}Ge by operating bare Ge detectors in liquid Ar. The talk focuses on the results of data acquired during Phase I of the experiment, in which 21.6 kg.yr of exposure were accumulated with a background index of about 0.01 cts/(keV.kg.yr). No signal was observed and a lower limit was derived for the half-life of neutrinoless double beta decay of {sup 76}Ge, T{sub 1/2} > 2.1 . 10{sup 25} yr (90% C.L.). The experiment is currently undergoing a major upgrade in preparation for the next phase of data taking. Thanks to an increased target mass, an improved energy resolution and the introduction of novel background reduction techniques, the sensitivity of Gerda will increase of about one order of magnitude in a few years of operation.
The Majorana Demonstrator: A search for neutrinoless double-beta decay of germanium-76
Elliott, S. R.; Abgrall, N.; Aguayo, E.; Avignone, F. T., III; Barabash, A. S.; Bertrand, F. E.; Boswell, M.; Brudanin, V.; Busch, M.; Caldwell, A. S.; Chan, Y.-D.; Christofferson, C. D.; Combs, D. C.; Detwiler, J. A.; Doe, P. J.; Efremenko, Yu.; Egorov, V.; Ejiri, H.; Esterline, J.; Fast, J. E.; Finnerty, P.; Fraenkle, F. M.; Galindo-Uribarri, A.; Giovanetti, G. K.; Goett, J.; Green, M. P.; Gruszko, J.; Guiseppe, V. E.; Gusev, K.; Hallin, A. L.; Hazama, R.; Hegai, A.; Henning, R.; Hoppe, E. W.; Howard, S.; Howe, M. A.; Keeter, K. J.; Kidd, M. F.; Kochetov, O.; Konovalov, S. I.; Kouzes, R. T.; LaFerriere, B. D.; Leon, J.; Leviner, L. E.; Loach, J. C.; MacMullin, S.; Martin, R. D.; Mertens, S.; Mizouni, L.; Nomachi, M.; Orrell, J. L.; O'Shaughnessy, C.; Overman, N. R.; Phillips, D. G., II; Poon, A. W. P.; Pushkin, K.; Radford, D. C.; Rielage, K.; Robertson, R. G. H.; Ronquest, M. C.; Schubert, A. G.; Shanks, B.; Shima, T.; Shirchenko, M.; Snavely, K. J.; Snyder, N.; Soin, A.; Strain, J.; Suriano, A. M.; Timkin, V.; Tornow, W.; Varner, R. L.; Vasilyev, S.; Vetter, K.; Vorren, K.; White, B. R.; Wilkerson, J. F.; Xu, W.; Yakushev, E.; Young, A. R.; Yu, C.-H.; Yumatov, V.
2013-12-01
The Majorana collaboration is searching for neutrinoless double beta decay using 76Ge, which has been shown to have a number of advantages in terms of sensitivities and backgrounds. The observation of neutrinoless double-beta decay would show that lepton number is violated and that neutrinos are Majorana particles and would simultaneously provide information on neutrino mass. Attaining sensitivities for neutrino masses in the inverted hierarchy region, 15 - 50 meV, will require large, tonne-scale detectors with extremely low backgrounds, at the level of ˜1 count/t-y or lower in the region of the signal. The Majorana collaboration, with funding support from DOE Office of Nuclear Physics and NSF Particle Astrophysics, is constructing the Demonstrator, an array consisting of 40 kg of p-type point-contact high-purity germanium (HPGe) detectors, of which ˜30 kg will be enriched to 87% in 76Ge. The Demonstrator is being constructed in a clean room laboratory facility at the 4850' level (4300 m.w.e.) of the Sanford Underground Research Facility (SURF) in Lead, SD. It utilizes a compact graded shield approach with the inner portion consisting of ultra-clean Cu that is being electroformed and machined underground. The primary aim of the Demonstrator is to show the feasibility of a future tonne-scale measurement in terms of backgrounds and scalability.
Superallowed Beta Decay Studies at TRIUMF --- Nuclear Structure and Fundamental Symmetries
Zganjar, E. F.; Achtzehn, T.; Albers, D.; Andreoiu, C.; Andreyev, A. N.; Austin, R. A. E.; Ball, G. C.; Behr, J. A.; Biosvert, G. C.; Bricault, P.; Bishop, S.; Chakrawarthy, R. S.; Churchman, R.; Cross, D.; Cunningham, E.; D'Auria, J. M.; Dombsky, M.; Finlay, P.; Garrett, P. E.; Grinyer, G. F.; Hackman, G.; Hanemaayer, V.; Hardy, J. C.; Hodgson, D. F.; Hyland, B.; Iacob, V.; Klages, P.; Koopmans, K. A.; Kulp, W. D.; Lassen, J.; Lavoie, J. P.; Leslie, J. R.; Linder, T.; MacDonald, J. A.; Mak, H.-B.; Melconian, D.; Morton, A. C.; Ormand, W. E.; Osborne, C. J.; Pearson, C. J.; Pearson, M. R.; Phillips, A. A.; Piechaczek, A.; Ressler, J.; Sarazin, F.; Savard, G.; Schumaker, M. A.; Scraggs, H. C.; Svensson, C. E.; Valiente-Dobon, J. J.; Towner, I. S.; Waddington, J. C.; Walker, P. M.; Wendt, K.; Wood, J. L.
2007-04-01
Precision measurement of the beta -decay half-life, Q-value, and branching ratio between nuclear analog states of Jpi = 0+ and T=1 can provide critical and fundamental tests of the Standard Model's description of electroweak interactions. A program has been initiated at TRIUMF-ISAC to measure the ft values of these superallowed beta transitions. Two Tz = 0, A > 60 cases, 74Rb and 62Ga, are presented. These are particularly relevant because they can provide critical tests of the calculated nuclear structure and isospin-symmetry breaking corrections that are predicted to be larger for heavier nuclei, and because they demonstrate the advance in the experimental precision on ft at TRIUMF-ISAC from 0.26% for 74Rb in 2002 to 0.05% for 62Ga in 2006. The high precision world data on experimental ft and corrected Ft values are discussed and shown to be consistent with CVC at the 10-4 level, yielding an average Ft = 3073.70(74) s. This Ft leads to Vud = 0.9737(4) for the up-down element of the Standard Model's CKM matrix. With this value and the Particle Data Group's 2006 values for Vus and Vub, the unitarity condition for the CKM matrix is met. Additional measurements and calculations are needed, however, to reduce the uncertainties in that evaluation. That objective is the focus of the continuing program on superallowed-beta decay at TRIUMF-ISAC.
Nuclear Matrix Elements for the $\\beta\\beta$ Decay of the $^{76}$Ge
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...
Investigation of double beta decay of {sup 100}Mo to excited states of {sup 100}Ru
Energy Technology Data Exchange (ETDEWEB)
Arnold, R. [IPHC, UPL, CNRS/IN2P3, F-67037 Strasbourg (France); Augier, C. [LAL, Univ Paris-Sud, CNRS/IN2P3, F-91405 Orsay (France); Barabash, A.S. [ITEP, Institute of Theoretical and Experimental Physics, 117218 Moscow (Russian Federation); Basharina-Freshville, A. [University College London, London WC1E 6BT (United Kingdom); Blondel, S. [LAL, Univ Paris-Sud, CNRS/IN2P3, F-91405 Orsay (France); Blot, S. [University of Manchester, Manchester M13 9PL (United Kingdom); Bongrand, M. [LAL, Univ Paris-Sud, CNRS/IN2P3, F-91405 Orsay (France); Brudanin, V. [JINR, Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Busto, J. [CPPM, Université de Marseille, CNRS/IN2P3, F-13288 Marseille (France); Caffrey, A.J. [Idaho National Laboratory, Idaho Falls, ID 83415 (United States); Čermák, P. [IEAP, Czech Technical University in Prague, CZ-12800 Prague (Czech Republic); Cerna, C. [CENBG, Université Bordeaux, CNRS/IN2P3, F-33175 Gradignan (France); Chapon, A. [LPC Caen, ENSICAEN, Université de Caen, CNRS/IN2P3, F-14050 Caen (France); Chauveau, E. [University of Manchester, Manchester M13 9PL (United Kingdom); Dragounová, L. [National Radiation Protection Institute, CZ-14000 Prague (Czech Republic); Duchesneau, D. [LAPP, Université de Savoie, CNRS/IN2P3, F-74941 Annecy-le-Vieux (France); Durand, D. [LPC Caen, ENSICAEN, Université de Caen, CNRS/IN2P3, F-14050 Caen (France); Egorov, V. [JINR, Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Eurin, G. [LAL, Univ Paris-Sud, CNRS/IN2P3, F-91405 Orsay (France); University College London, London WC1E 6BT (United Kingdom); Evans, J.J. [University of Manchester, Manchester M13 9PL (United Kingdom); and others
2014-05-15
Double beta decay of {sup 100}Mo to the excited states of daughter nuclei has been studied using a 600 cm{sup 3} low-background HPGe detector and an external source consisting of 2588 g of 97.5% enriched metallic {sup 100}Mo, which was formerly inside the NEMO-3 detector and used for the NEMO-3 measurements of {sup 100}Mo. The half-life for the two-neutrino double beta decay of {sup 100}Mo to the excited 0{sub 1}{sup +} state in {sup 100}Ru is measured to be T{sub 1/2}=[7.5±0.6(stat)±0.6(syst)]⋅10{sup 20} yr. For other (0ν+2ν) transitions to the 2{sub 1}{sup +}, 2{sub 2}{sup +}, 0{sub 2}{sup +}, 2{sub 3}{sup +} and 0{sub 3}{sup +} levels in {sup 100}Ru, limits are obtained at the level of ∼(0.25–1.1)⋅10{sup 22} yr.
Measurement of the form factor ratio g1/f1 in LAMBDA beta decay
International Nuclear Information System (INIS)
Innes, W.R.
1974-01-01
The beta decay of 306 polarized lambdas was observed. The lambdas, which had a mean polarization of 70 percent, were produced by a 1.06 GeV/c π minus beam incident on a CH 2 target. The lambda decay particle trajectories were measured with a solenoidal magnetic spectrometer utilizing spark chambers with magnetostrictive readout. The beta decays were differentiated from other decay modes with an isobutane threshold Cherenkov counter. Using only information which depended upon the polarization, g 1 /f 1 was found to be 0.44- 0 . 13 +0 . 20 . Using only information independent of the polarization, g 1 /f 1 was found to be 0.62- 0 . 13 +0 . 17 . Combining all information yielded a value for g 1 /f 1 of 0.56- 0 . 11 +0 . 13 . Although these results taken by themselves are consistent with the Cabbibo theory prediction of 0.69, when combined with previous experiments there is a possibly significant discrepancy in the polarization dependent results. (U.S.)
Beta decay of 72Co and excited levels in 72Ni
International Nuclear Information System (INIS)
Grzywacz, R.; Rykaczewski, K.; Sawicka, M.; Pfuetzner, M.; Daugas, J.M.; Belier, G.; Sauvestre, J.E.; Meot, V.; Roig, O.; Giovinazzo, J.; Grawe, H.; Mayet, P.; Matea, I.; Georgiev, G.; Lewitowicz, M.; Olivieira, F. de; Stodel, C.; Saint-Laurent, M. G.; Stanoiu, M.; Verney, D.
2003-01-01
An experiment was performed at GANIL to observe isomeric- and beta-delayed gamma rays from very neutron-rich nuclei around 74Ni. Fragmentation products of the 86Kr beam at 58 AMeV were studied using new devices: the LISE 2000 spectrometer and detectors from the EXOGAM germanium array. The primary aim of the experiment was to find the 8+ microsecond isomer in 76Ni and to perform beta decay spectroscopy of Co nuclei. We have successfully measured the beta delayed gammas from the decay of 72Co to 72Ni. The energies for the lowest excited states in 72Ni are proposed, with the first 2+ state at 1096 keV. These findings suggest a solution of the problem of the disappearance of the 8+ isomer in 72Ni. We also measured beta decay of other neutron-rich Co isotopes including 70Co. First evidence was found for a new short lived isomer, most likely the Iπ=8+ state, in 76Ni
Few active mechanisms of the neutrinoless double beta-decay and effective mass of Majorana neutrinos
Simkovic, Fedor; Faessler, Amand
2010-01-01
It is well known that there exist many mechanisms that may contribute to neutrinoless double beta decay (0nbb-decay). By exploiting the fact that the associated nuclear matrix elements are target dependent we show that, given definite experimental results on a sufficient number of targets, one can determine or sufficiently constrain all lepton violating parameters including the mass term. As a specific example we show that, assuming the observation of the 0nbb-decay in three different nuclei, e.g., 76Ge, 100Mo and 130Te, and just three lepton number violating mechanisms (light and heavy neutrino mass mechanisms as well as R-parity breaking SUSY mechanism) being active, there are only four different solutions for the lepton violating parameters, provided that they are relatively real. In particular, assuming evidence of the 0nbb-decay of 76Ge, the effective neutrino Majorana mass |m_bb| can be almost uniquely extracted by utilizing other existing constraints (cosmological observations and tritium beta-decay ex...
The next enriched xenon observatory. A search for neutrinoless double beta decay
Energy Technology Data Exchange (ETDEWEB)
Bayerlein, Reimund; Hufschmidt, Patrick; Jamil, Ako; Schneider, Judith; Wagenpfeil, Michael; Wrede, Gerrit; Ziegler, Tobias; Hoessl, Juergen; Anton, Gisela; Michel, Thilo [ECAP, Friedrich-Alexander-Universitaet Erlangen-Nuernberg (Germany)
2016-07-01
The question whether the neutrino could be its own antiparticle is still not answered. The most practical way to test this is the search for the neutrinoless double beta decay. The half-life of this decay is related to the value of a linear combination of the masses of the neutrino mass eigenstates and therefore provides information about the absolute mass scale of neutrinos. The nEXO experiment - the successor of EXO200 - is currently under research and development. The baseline concept comprises a single-phase liquid xenon (LXe) time projection chamber (TPC) filled with about 5 tons of liquid xenon enriched to about 80% Xe-136 as the double beta decay nuclide. In order to fully cover the range of the effective Majorana neutrino mass in the inverted hierarchy scheme, excellent energy resolution is required. Therefore, a position-resolving, low-noise charge readout and very efficient light collection and detection are mandatory. For the purpose of very low background levels radiopure Silicon Photomultipliers (SiPMs) have to be used to detect the scintillation light of LXe. Due to the large half-life a huge detector mass and long term measurement are needed. In this talk the baseline-concept of the experimental setup is presented.
Recent advances in bound state quantum electrodynamics
International Nuclear Information System (INIS)
Brodsky, S.J.; Lepage, G.P.
1977-06-01
Recent developments are reviewed in four areas of computational quantum electrodynamics: a new relativistic two-body formalism equal in rigor to the Bethe-Salpeter formalism but with strong calculational advantages is discussed; recent work on the computation of the decay rate of bound systems (positronium in particular) is presented; limits on possible composite structure of leptons are discussed; a new multidimensional integration program ('VEGAS') suitable for higher order calculations is presented
2002-01-01
% IS353 \\\\ \\\\ Due to its importance in fundamental physics and astrophysics, a great effort both theoretically and experimentally is devoted to study Gamow Teller (GT)-strength. The GT-strength and its distribution play a key role in late stellar evolution. During the pre-supernova core-collapse of massive stars, the electron capture and nuclear $\\beta$ -decay determine the electron-to-baryon ratio, which influences the infall dynamics and the mass of the final core. The cross-section of the charge-exchange reaction at forward angles with energies above 100~MeV is expected to be proportional to the squares of Fermi and GT matrix elements. This proportionality should provide a Q-value free method to probe the weak interaction strength and renormalization effects in nuclei. Thus charge-exchange reactions are often used to determine the experimental GT-strength. However, the connection between the GT-strength and the cross-section of the charge-exchange reaction is partially model-dependent and the question aris...
Finnerty, P.; Aguayo, E.; Amman, M.; Avignone, F. T., Iii; Barabash, A. S.; Barton, P. J.; Beene, J. R.; Bertrand, F. E.; Boswell, M.; Brudanin, V.; Busch, M.; Chan, Y.-D.; Christofferson, C. D.; Collar, J. I.; Combs, D. C.; Cooper, R. J.; Detwiler, J. A.; Doe, P. J.; Efremenko, Yu; Egorov, V.; Ejiri, H.; Elliott, S. R.; Esterline, J.; Fast, J. E.; Fields, N.; Fraenkle, F. M.; Galindo-Uribarri, A.; Gehman, V. M.; Giovanetti, G. K.; Green, M. P.; Guiseppe, V. E.; Gusey, K.; Hallin, A. L.; Hazama, R.; Henning, R.; Hoppe, E. W.; Horton, M.; Howard, S.; Howe, M. A.; Johnson, R. A.; Keeter, K. J.; Kidd, M. F.; Knecht, A.; Kochetov, O.; Konovalov, S. I.; Kouzes, R. T.; LaFerriere, B. D.; Leon, J.; Leviner, L. E.; Loach, J. C.; Luke, P. N.; MacMullin, S.; Marino, M. G.; Martin, R. D.; Merriman, J. H.; Miller, M. L.; Mizouni, L.; Nomachi, M.; Orrell, J. L.; Overman, N. R.; Perumpilly, G.; Phillips, D. G., Ii; Poon, A. W. P.; Radford, D. C.; Rielage, K.; Robertson, R. G. H.; Ronquest, M. C.; Schubert, A. G.; Shima, T.; Shirchenko, M.; Snavely, K. J.; Steele, D.; Strain, J.; Timkin, V.; Tornow, W.; Varner, R. L.; Vetter, K.; Vorren, K.; Wilkerson, J. F.; Yakushev, E.; Yaver, H.; Young, A. R.; Yu, C.-H.; Yumatov, V.; Majorana Collaboration
2014-03-01
The Majorana Demonstrator will search for the neutrinoless double-beta decay (0vββ) of the 76Ge isotope with a mixed array of enriched and natural germanium detectors. The observation of this rare decay would indicate the neutrino is its own anti-particle, demonstrate that lepton number is not conserved, and provide information on the absolute mass-scale of the neutrino. The Demonstrator is being assembled at the 4850 foot level of the Sanford Underground Research Facility in Lead, South Dakota. The array will be contained in a low-background environment and surrounded by passive and active shielding. The goals for the Demonstrator are: demonstrating a background rate less than 3 t-1 y-1 in the 4 keV region of interest (ROI) surrounding the 2039 keV 76Ge endpoint energy; establishing the technology required to build a tonne-scale germanium based double-beta decay experiment; testing the recent claim of observation of 0vββ [1]; and performing a direct search for light WIMPs (3-10 GeV/c2).
Realistic fission models, new beta-decay half-lives and the r-process in neutron star mergers
International Nuclear Information System (INIS)
Shibagaki, S.; Kajino, T.; Chiba, S.; Lorusso, G.; Nishimura, S.; Mathews, G. J.
2014-01-01
Almost half of heavy nuclei beyond iron are considered to be produced by rapid neutron capture process (r-process). This process occurs in the neutron-rich environment such as core-collapse supernovae or neutron star mergers, but the main production site is still unknown. In the r-process of neutron star mergers, nuclear fission reactions play an important role. Also beta-decay half-lives of magic nuclei are crucial for the r-process. We have carried out r-process nucleosynthesis calculations based upon new theoretical estimates of fission fragment distributions and new beta-decay half-lives for N=82 nuclei measured at RIBF-RIKEN. We investigate the effect of nuclear fission on abundance patterns in the matter ejected from neutron star mergers with two different fission fragment mass distributions. We also discuss how the new experimental beta-decay half-lives affect the r-process
Double beta decay searches of 134Xe, 126Xe and 124Xe with large scale Xe detectors
International Nuclear Information System (INIS)
Barros, N; Thurn, J; Zuber, K
2014-01-01
The sensitivity for double beta decay studies of 134 Xe and 124 Xe is investigated assuming a potential large scale Xe experiment developed for dark matter searches depleted in 136 Xe. The opportunity for an observation of the 2νββ - decay of 134 Xe is explored for various scenarios. A positive observation should be possible for all calculated nuclear matrix elements. The detection of 2ν ECEC of 124 Xe can be probed in all scenarios covering the theoretical predicted half-life uncertainties and a potential search for 126 Xe is discussed. The sensitivity to β + EC decay of 124 Xe is discussed and a positive observation might be possible, while β + β + decay still remains unobservable. The performed studies take into account solar pp–neutrino interactions, 85 Kr beta decay and remaining 136 Xe double beta decay as background components in the depleted detector. (paper)
Massarczyk, Ralph; Majorana Collaboration
2015-10-01
Cosmic radiation creates a significant background for low count rate experiments. The Majorana demonstrator experiment is located at the Sanford Underground Research Facility at a depth of 4850ft below the surface but it can still be penetrated by cosmic muons with initial energies above the TeV range. The interaction of muons with the rock, the shielding material in the lab and the detector itself can produce showers of secondary particles, like fast neutrons, which are able to travel through shielding material and can produce high-energy γ-rays via capture or inelastic scattering. The energy deposition of these γ rays in the detector can overlap with energy region of interest for the neutrino-less double beta decay. Recent studies for cosmic muons penetrating the Majorana demonstrator are made with the Geant4 code. The results of these simulations will be presented in this talk and an overview of the interaction of the shower particles with the detector, shielding and veto system will be given. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, the Particle Astrophysics Program of the National Science Foundation, and the Sanford Underground Research Facility. Supported by U.S. Department of Energy through the LANL/LDRD Program.
Estevez Aguado, M.E.; Agramunt, J.; Rubio, B.; Tain, J.L.; Jordan, D.; Fraile, L.M.; Gelletly, W.; Frank, A.; Csatlos, M.; Csige, L.; Dombradi, Zs.; Krasznahorkay, A.; Nacher, E.; Sarriguren, P.; Borge, M.J.G.; Briz, J.A.; Tengblad, O.; Molina, F.; Moreno, O.; Kowalska, M.; Fedosseev, V.N.; Marsh, B.A.; Fedorov, D.V.; Molkanov, P.L.; Andreyev, A.N.; Seliverstov, M.D.; Burkard, K.; Huller, W.
2015-01-01
The beta decay of $^{192,190}$Pb has been studied using the total absorption technique at the ISOLDE(CERN) facility. The beta-decay strength deduced from the measurements, combined with QRPA theoretical calculations, allow us to infer that the ground states of the $^{192,190}$Pb isotopes are spherical. These results represent the first application of the shape determination method using the total absorption technique for heavy nuclei and in a region where there is considerable interest in nuclear shapes and shape effects.
McDonald, A. D.; Jones, B. J. P.; Nygren, D. R.; Adams, C.; Álvarez, V.; Azevedo, C. D. R.; Benlloch-Rodríguez, J. M.; Borges, F. I. G. M.; Botas, A.; Cárcel, S.; Carrión, J. V.; Cebrián, S.; Conde, C. A. N.; Díaz, J.; Diesburg, M.; Escada, J.; Esteve, R.; Felkai, R.; Fernandes, L. M. P.; Ferrario, P.; Ferreira, A. L.; Freitas, E. D. C.; Goldschmidt, A.; Gómez-Cadenas, J. J.; González-Díaz, D.; Gutiérrez, R. M.; Guenette, R.; Hafidi, K.; Hauptman, J.; Henriques, C. A. O.; Hernandez, A. I.; Hernando Morata, J. A.; Herrero, V.; Johnston, S.; Labarga, L.; Laing, A.; Lebrun, P.; Liubarsky, I.; López-March, N.; Losada, M.; Martín-Albo, J.; Martínez-Lema, G.; Martínez, A.; Monrabal, F.; Monteiro, C. M. B.; Mora, F. J.; Moutinho, L. M.; Muñoz Vidal, J.; Musti, M.; Nebot-Guinot, M.; Novella, P.; Palmeiro, B.; Para, A.; Pérez, J.; Querol, M.; Repond, J.; Renner, J.; Riordan, S.; Ripoll, L.; Rodríguez, J.; Rogers, L.; Santos, F. P.; dos Santos, J. M. F.; Simón, A.; Sofka, C.; Sorel, M.; Stiegler, T.; Toledo, J. F.; Torrent, J.; Tsamalaidze, Z.; Veloso, J. F. C. A.; Webb, R.; White, J. T.; Yahlali, N.; NEXT Collaboration
2018-03-01
A new method to tag the barium daughter in the double-beta decay of Xe 136 is reported. Using the technique of single molecule fluorescent imaging (SMFI), individual barium dication (Ba++ ) resolution at a transparent scanning surface is demonstrated. A single-step photobleach confirms the single ion interpretation. Individual ions are localized with superresolution (˜2 nm ), and detected with a statistical significance of 12.9 σ over backgrounds. This lays the foundation for a new and potentially background-free neutrinoless double-beta decay technology, based on SMFI coupled to high pressure xenon gas time projection chambers.
Energy Technology Data Exchange (ETDEWEB)
McDonald, A. D.; Jones, B. J. P.; Nygren, D. R.; Adams, C.; Álvarez, V.; Azevedo, C. D. R.; Benlloch-Rodríguez, J. M.; Borges, F. I. G. M.; Botas, A.; Cárcel, S.; Carrión, J. V.; Cebrián, S.; Conde, C. A. N.; Díaz, J.; Diesburg, M.; Escada, J.; Esteve, R.; Felkai, R.; Fernandes, L. M. P.; Ferrario, P.; Ferreira, A. L.; Freitas, E. D. C.; Goldschmidt, A.; Gómez-Cadenas, J. J.; González-Díaz, D.; Gutiérrez, R. M.; Guenette, R.; Hafidi, K.; Hauptman, J.; Henriques, C. A. O.; Hernandez, A. I.; Hernando Morata, J. A.; Herrero, V.; Johnston, S.; Labarga, L.; Laing, A.; Lebrun, P.; Liubarsky, I.; López-March, N.; Losada, M.; Martín-Albo, J.; Martínez-Lema, G.; Martínez, A.; Monrabal, F.; Monteiro, C. M. B.; Mora, F. J.; Moutinho, L. M.; Muñoz Vidal, J.; Musti, M.; Nebot-Guinot, M.; Novella, P.; Palmeiro, B.; Para, A.; Pérez, J.; Querol, M.; Repond, J.; Renner, J.; Riordan, S.; Ripoll, L.; Rodríguez, J.; Rogers, L.; Santos, F. P.; dos Santos, J. M. F.; Simón, A.; Sofka, C.; Sorel, M.; Stiegler, T.; Toledo, J. F.; Torrent, J.; Tsamalaidze, Z.; Veloso, J. F. C. A.; Webb, R.; White, J. T.; Yahlali, N.
2018-03-01
A new method to tag the barium daughter in the double beta decay of $^{136}$Xe is reported. Using the technique of single molecule fluorescent imaging (SMFI), individual barium dication (Ba$^{++}$) resolution at a transparent scanning surface has been demonstrated. A single-step photo-bleach confirms the single ion interpretation. Individual ions are localized with super-resolution ($\\sim$2~nm), and detected with a statistical significance of 12.9~$\\sigma$ over backgrounds. This lays the foundation for a new and potentially background-free neutrinoless double beta decay technology, based on SMFI coupled to high pressure xenon gas time projection chambers.
Background constrains of the SuperNEMO experiment for neutrinoless double beta-decay searches
Energy Technology Data Exchange (ETDEWEB)
Povinec, Pavel P.
2017-02-11
The SuperNEMO experiment is a new generation of experiments dedicated to the search for neutrinoless double beta-decay, which if observed, would confirm the existence of physics beyond the Standard Model. It is based on the tracking and calorimetry techniques, which allow the reconstruction of the final state topology, including timing and kinematics of the double beta-decay transition events, offering a powerful tool for background rejection. While the basic detection strategy of the SuperNEMO detector remains the same as of the NEMO-3 detector, a number of improvements were accomplished for each of detector main components. Upgrades of the detector technologies and development of low-level counting techniques ensure radiopurity control of construction parts of the SuperNEMO detector. A reference material made of glass pellets has been developed to assure quality management and quality control of radiopurity measurements. The first module of the SuperNEMO detector (Demonstrator) is currently under construction in the Modane underground laboratory. No background event is expected in the neutrinoless double beta-decay region in 2.5 years of its operation using 7 kg of {sup 82}Se. The half-life sensitivity of the Demonstrator is expected to be >6.5·10{sup 24} y, corresponding to an effective Majorana neutrino mass sensitivity of |0.2−0.4| eV (90% C.L.). The full SuperNEMO experiment comprising of 20 modules with 100 kg of {sup 82}Se source should reach an effective Majorana neutrino mass sensitivity of |0.04−0.1| eV, and a half-life limit 1·10{sup 26} y. - Highlights: • SuperNEMO detector for 2β0ν-decay of {sup 82}Se should reach half-life limit of 10{sup 26} y. • Radiopurity of the SuperNEMO internal detector parts was checked down to 0.1 mBq/kg. • Reference material of glass pellets was developed for underground γ-spectrometry.
Relativistic bound state approach to fundamental forces including gravitation
Directory of Open Access Journals (Sweden)
Morsch H.P.
2012-06-01
Full Text Available To describe the structure of particle bound states of nature, a relativistic bound state formalism is presented, which requires a Lagrangian including scalar coupling of two boson fields. The underlying mechanisms are quite complex and require an interplay of overlapping boson fields and fermion-antifermion production. This gives rise to two potentials, a boson-exchange potential and one identified with the long sought confinement potential in hadrons. With minimal requirements, two elementary massless fermions (quantons - with and without charge - and one gauge boson, hadrons and leptons but also atoms and gravitational systems are described by bound states with electric and magnetic coupling between the charges and spins of quantons. No need is found for colour, Higgs-coupling and supersymmetry.
Universal extra dimensions and Kaluza-Klein bound states
International Nuclear Information System (INIS)
Carone, Christopher D.; Conroy, Justin M.; Sher, Marc; Turan, Ismail
2004-01-01
We study the bound states of the Kaluza-Klein (KK) excitations of quarks in certain models of universal extra dimensions. Such bound states may be detected at future lepton colliders in the cross section for the pair production of KK quarks near threshold. For typical values of model parameters, we find that 'KK quarkonia' have widths in the 10-100 MeV range, and production cross sections of the order of a few picobarns for the lightest resonances. Two body decays of the constituent KK quarks lead to distinctive experimental signatures. We point out that such KK resonances may be discovered before any of the higher KK modes
Usefulness of bound-state approximations in reaction theory
International Nuclear Information System (INIS)
Adhikari, S.K.
1981-01-01
A bound-state approximation when applied to certain operators, such as the many-body resolvent operator for a two-body fragmentation channel, in many-body scattering equations, reduces such equations to equivalent two-body scattering equations which are supposed to provide a good description of the underlying physical process. In this paper we test several variants of bound-state approximations in the soluble three-boson Amado model and find that such approximations lead to weak and unacceptable kernels for the equivalent two-body scattering equations and hence to a poor description of the underlying many-body process
Neutrino mass from laboratory: contribution of double beta decay to the neutrino mass matrix
International Nuclear Information System (INIS)
Klapdor-Kleingrothaus, H.V.
2001-01-01
Double beta decay is indispensable to solve the question of the neutrino mass matrix together with ν oscillation experiments. The most sensitive experiment - since eight years the HEIDELBERG-MOSCOW experiment in Gran-Sasso - already now, with the experimental limit of ν > < 0.26 eV practically excludes degenerate ν mass scenarios allowing neutrinos as hot dark matter in the universe for the smallangle MSW solution of the solar neutrino problem. It probes cosmological models including hot dark matter already now on the level of future satellite experiments MAP and PLANCK. It further probes many topics of beyond SM physics at the TeV scale. Future experiments should give access to the multi-TeV range and complement on many ways the search for new physics at future colliders like LHC and NLC. For neutrino physics some of them (GENIUS) will allow to test almost all neutrino mass scenarios allowed by the present neutrino oscillation experiments
Exploration of Pixelated detectors for double beta decay searches within the COBRA experiment
Energy Technology Data Exchange (ETDEWEB)
Schwenke, M., E-mail: schwenke@asp.tu-dresden.de [Institut fuer Kern- und Teilchenphysik, Technische Universitaet Dresden, Zellescher Weg 19, 01069 Dresden (Germany); Zuber, K.; Janutta, B. [Institut fuer Kern- und Teilchenphysik, Technische Universitaet Dresden, Zellescher Weg 19, 01069 Dresden (Germany); He, Z.; Zeng, F. [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, Michigan 48109-2104 (United States); Anton, G.; Michel, T.; Durst, J.; Lueck, F.; Gleixner, T. [Erlangen Centre for Astroparticle Physics, Friedrich-Alexander-Universitaet Erlangen-Nuernberg, Erwin-Rommel-Str. 1, 91058 Erlangen (Germany); Goessling, C.; Schulz, O.; Koettig, T. [Technische Universitaet Dortmund, Physik E IV, 44221 Dortmund (Germany); Krawczynski, H.; Martin, J. [Department of Physics, Washington University in St. Louis, Campus Box 1105, One Brookings Drive, St. Louis, MO 63130-4899 (United States); Stekl, I.; Cermak, P. [Institute of Experimental and Applied Physics, Czech Technical University in Prague, Horska 3a/22, 128 00 Prague (Czech Republic)
2011-09-11
The aim of the COBRA experiment is the search for neutrinoless double beta decay events in Cadmium Zinc Telluride (CdZnTe) room temperature semiconductor detectors. The development of pixelated detectors provides the potential for clear event identification and thus major background reduction. The tracking option of a semiconductor is a unique approach in this field. For initial studies, several possible detector systems are considered with a special regard for low background applications: the large volume system Polaris with a pixelated CdZnTe sensor, Timepix detectors with Si and enriched CdTe sensor material and a CdZnTe pixel system developed at the Washington University in St. Louis, USA. For all detector systems first experimental background measurements taken at underground laboratories (Gran Sasso Underground Laboratory in Italy, LNGS and the Niederniveau Messlabor Felsenkeller in Dresden, Germany) and additionally for the Timepix detectors simulation results are presented.
Status of the CUORE and results from the CUORE-0 neutrinoless double beta decay experiments
Sisti, M.; Artusa, D. R.; Avignone, F. T.; Azzolini, O.; Balata, M.; Banks, T. I.; Bari, G.; Beeman, J.; Bellini, F.; Bersani, A.; Biassoni, M.; Brofferio, C.; Bucci, C.; Cai, X. Z.; Camacho, A.; Caminata, A.; Canonica, L.; Cao, X. G.; Capelli, S.; Cappelli, L.; Carbone, L.; Cardani, L.; Casali, N.; Cassina, L.; Chiesa, D.; Chott, N.; Clemenza, M.; Copello, S.; Cosmelli, C.; Cremonesi, O.; Creswick, R. J.; Cushman, J. S.; Dafinei, I.; Dally, A.; Datskov, V.; Dell'Oro, S.; Deninno, M. M.; Di Domizio, S.; di Vacri, M. L.; Drobizhev, A.; Ejzak, L.; Fang, D. Q.; Farach, H. A.; Faverzani, M.; Fernandes, G.; Ferri, E.; Ferroni, F.; Fiorini, E.; Franceschi, M. A.; Freedman, S. J.; Fujikawa, B. K.; Giachero, A.; Gironi, L.; Giuliani, A.; Gorla, P.; Gotti, C.; Gutierrez, T. D.; Haller, E. E.; Han, K.; Heeger, K. M.; Hennings-Yeomans, R.; Hickerson, K. P.; Huang, H. Z.; Kadel, R.; Keppel, G.; Kolomensky, Yu. G.; Li, Y. L.; Ligi, C.; Lim, K. E.; Liu, X.; Ma, Y. G.; Maiano, C.; Maino, M.; Martinez, M.; Maruyama, R. H.; Mei, Y.; Moggi, N.; Morganti, S.; Napolitano, T.; Nastasi, M.; Nisi, S.; Nones, C.; Norman, E. B.; Nucciotti, A.; O'Donnell, T.; Orio, F.; Orlandi, D.; Ouellet, J. L.; Pagliarone, C. E.; Pallavicini, M.; Palmieri, V.; Pattavina, L.; Pavan, M.; Pedretti, M.; Pessina, G.; Pettinacci, V.; Piperno, G.; Pira, C.; Pirro, S.; Pozzi, S.; Previtali, E.; Rosenfeld, C.; Rusconi, C.; Sala, E.; Sangiorgio, S.; Scielzo, N. D.; Smith, A. R.; Taffarello, L.; Tenconi, M.; Terranova, F.; Tian, W. D.; Tomei, C.; Trentalange, S.; Ventura, G.; Vignati, M.; Wang, B. S.; Wang, H. W.; Wielgus, L.; Wilson, J.; Winslow, L. A.; Wise, T.; Woodcraft, A.; Zanotti, L.; Zarra, C.; Zhang, G. Q.; Zhu, B. X.; Zucchelli, S.
2016-04-01
CUORE is a 741 kg array of TeO2 bolometers for the search of neutrinoless double beta decay of 130Te. The detector is being constructed at the Laboratori Nazionali del Gran Sasso, Italy, where it will start taking data in 2015. If the target background of 0.01 counts / (keV ṡkg ṡy) will be reached, in five years of data taking CUORE will have a 1σ half life sensitivity of 1026 y. CUORE-0 is a smaller experiment constructed to test and demonstrate the performances expected for CUORE. The detector is a single tower of 52 CUORE-like bolometers that started taking data in spring 2013. The status and perspectives of CUORE will be discussed, and the first CUORE-0 data will be presented.
Phase II Upgrade of the GERDA Experiment for the Search of Neutrinoless Double Beta Decay
Majorovits, B.
Observation of neutrinoless double beta decay could answer the question regarding the Majorana or Dirac nature of neutrinos. The GERDA experiment utilizes HPGe detectors enriched with the isotope 76Ge to search for this process. Recently the GERDA collaboration has unblinded data of Phase I of the experiment. In order to further improve the sensitivity of the experiment, additionally to the coaxial detectors used, 30 BEGe detectors made from germanium enriched in 76Ge will be deployed in GERDA Phase II. BEGe detectors have superior PSD capability, thus the background can be further reduced. The liquid argon surrounding the detector array will be instrumented in order to reject background by detecting scintillation light induced in the liquid argon by radiation. After a short introduction the hardware preparations for GERDA Phase II as well as the processing and characterization of the 30 BEGe detectors are discussed.
Research and Development Supporting a Next Generation Germanium Double Beta Decay Experiment
Rielage, Keith; Elliott, Steve; Chu, Pinghan; Goett, Johnny; Massarczyk, Ralph; Xu, Wenqin
2015-10-01
To improve the search for neutrinoless double beta decay, the next-generation experiments will increase in source mass and continue to reduce backgrounds in the region of interest. A promising technology for the next generation experiment is large arrays of Germanium p-type point contact detectors enriched in 76-Ge. The experience, expertise and lessons learned from the MAJORANA DEMONSTRATOR and GERDA experiments naturally lead to a number of research and development activities that will be useful in guiding a future experiment utilizing Germanium. We will discuss some R&D activities including a hybrid cryostat design, background reduction in cabling, connectors and electronics, and modifications to reduce assembly time. We acknowledge the support of the U.S. Department of Energy through the LANL/LDRD Program.
Study of the Beta-Decay Properties of Extremely Proton-Rich Nuclei
2002-01-01
The most proton-rich nuclei known to date have isospin projections $ T _{Z} $ ~=~-3/2, -2 and -5/2. \\\\ \\\\ We propose to carry out a study of their superallowed beta decays, a phenomenon that can only be studied in this region of the nuclear chart. The main aim is to determine the ``effective charge'' in nuclei of the axial vector coupling, the quantity $ ( g'_{A} / g _{A} ) ^{2} $ , which in a recent first experiment on a ~~ $ T _{Z} $~~=~-2 nucleus was determined to be 0.49~$\\pm$~0.05. \\\\ \\\\ Because of the problems connected with the production and acceleration of radioactive ions, our proposal aims at selected elements: neon, argon and rubidium (production runs), magnesium (test and production runs) and calcium (test). Data have so far been taken for $^1
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.
Neutrinoless double-beta decay in left-right symmetric models
International Nuclear Information System (INIS)
Picciotto, C.E.; Zahir, M.S.
1982-06-01
Neutrinoless double-beta decay is calculated via doubly charged Higgs, which occur naturally in left-right symmetric models. We find that the comparison with known half-lives yields values of phenomenological parameters which are compatible with earlier analyses of neutral current data. In particular, we obtain a right-handed gauge-boson mass lower bound of the order of 240 GeV. Using this result and expressions for neutrino masses derived in a parity non-conserving left-right symmetric model, we obtain msub(νsub(e)) < 1.5 eV, msub(νsub(μ)) < 0.05 MeV and msub(νsub(tau)) < 18 MeV
A segmented, enriched N-type germanium detector for neutrinoless double beta-decay experiments
Leviner, L. E.; Aalseth, C. E.; Ahmed, M. W.; Avignone, F. T.; Back, H. O.; Barabash, A. S.; Boswell, M.; De Braeckeleer, L.; Brudanin, V. B.; Chan, Y.-D.; Egorov, V. G.; Elliott, S. R.; Gehman, V. M.; Hossbach, T. W.; Kephart, J. D.; Kidd, M. F.; Konovalov, S. I.; Lesko, K. T.; Li, Jingyi; Mei, D.-M.; Mikhailov, S.; Miley, H.; Radford, D. C.; Reeves, J.; Sandukovsky, V. G.; Umatov, V. I.; Underwood, T. A.; Tornow, W.; Wu, Y. K.; Young, A. R.
2014-01-01
We present data characterizing the performance of the first segmented, N-type Ge detector, isotopically enriched to 85% 76Ge. This detector, based on the Ortec PT6×2 design and referred to as SEGA (Segmented, Enriched Germanium Assembly), was developed as a possible prototype for neutrinoless double beta-decay measurements by the MAJORANA collaboration. We present some of the general characteristics (including bias potential, efficiency, leakage current, and integral cross-talk) for this detector in its temporary cryostat. We also present an analysis of the resolution of the detector, and demonstrate that for all but two segments there is at least one channel that reaches the MAJORANA resolution goal below 4 keV FWHM at 2039 keV, and all channels are below 4.5 keV FWHM.
Neutrino nuclear responses for double beta decays and astro neutrinos by charge exchange reactions
Ejiri, Hiroyasu
2014-09-01
Neutrino nuclear responses are crucial for neutrino studies in nuclei. Charge exchange reactions (CER) are shown to be used to study charged current neutrino nuclear responses associated with double beta decays(DBD)and astro neutrino interactions. CERs to be used are high energy-resolution (He3 ,t) reactions at RCNP, photonuclear reactions via IAR at NewSUBARU and muon capture reactions at MUSIC RCNP and MLF J-PARC. The Gamow Teller (GT) strengths studied by CERs reproduce the observed 2 neutrino DBD matrix elements. The GT and spin dipole (SD) matrix elements are found to be reduced much due to the nucleon spin isospin correlations and the non-nucleonic (delta isobar) nuclear medium effects. Impacts of the reductions on the DBD matrix elements and astro neutrino interactions are discussed.
Pions in nuclei and manifestations of supersymmetry in neutrinoless double beta decay
International Nuclear Information System (INIS)
Faessler, A.; Kovalenko, S.; Simkovic, F.
1998-01-01
We examine the pion realization of the short ranged supersymmetric (SUSY) mechanism of neutrinoless double beta decay (0νββ-decay). It originates from the R-parity violating quark-lepton interactions of the SUSY extensions of the standard model of the electroweak interactions. We argue that pions are dominant SUSY mediators in 0νββ-decay. The corresponding nuclear matrix elements for potentially 0νββ-decaying isotopes are calculated within the proton-neutron renormalized quasiparticle random phase approximation (pn-RQRPA). We define those isotopes which are most sensitive to the SUSY signal and outlook the present experimental situation with the 0νββ-decay searches for the SUSY. Upper limits on the R-parity violating 1st generation Yukawa coupling λ' 111 are derived from various 0νββ - experiments
Determination of the direction to a source of antineutrinos via inverse beta decay in Double Chooz
Nikitenko, Ya.
2016-11-01
To determine the direction to a source of neutrinos (and antineutrinos) is an important problem for the physics of supernovae and of the Earth. The direction to a source of antineutrinos can be estimated through the reaction of inverse beta decay. We show that the reactor neutrino experiment Double Chooz has unique capabilities to study antineutrino signal from point-like sources. Contemporary experimental data on antineutrino directionality is given. A rigorous mathematical approach for neutrino direction studies has been developed. Exact expressions for the precision of the simple mean estimator of neutrinos' direction for normal and exponential distributions for a finite sample and for the limiting case of many events have been obtained.
Beta Decay in the Field of an Electromagnetic Wave and Experiments on Measuring the Neutrino Mass
International Nuclear Information System (INIS)
Dorofeev, O.F.; Lobanov, A.E.
2005-01-01
Investigations of the effect of an electromagnetic wave field on the beta-decay process are used to analyze the tritium-decay experimental data on the neutrino mass. It is shown that the electromagnetic wave can distort the beta spectrum, shifting the end point to the higher energy region. This phenomenon is purely classical and it is associated with the electron acceleration in the radiation field. Since strong magnetic fields exist in setups for precise measurement of the neutrino mass, the indicated field can appear owing to the synchrotron radiation mechanism. The phenomenon under consideration can explain the experimentally observed anomalies in the spectrum of the decay electrons; in particular, the effect of the 'negative square of the neutrino mass'
International Nuclear Information System (INIS)
Álvarez, V; Cárcel, S; Cervera, A; Díaz, J; Ferrario, P; Bandac, I; Bettini, A; Castel, J; Cebrián, S; Dafni, T; Borges, F I G M; Conde, C A N; Dias, T H V T; Fernandes, L M P; Freitas, E D C; Egorov, M; Gehman, V M; Esteve, R; Evtoukhovitch, P; Ferreira, A L
2013-01-01
The ''Neutrino Experiment with a Xenon Time-Projection Chamber'' (NEXT) is intended to investigate the neutrinoless double beta decay of 136 Xe, which requires a severe suppression of potential backgrounds. An extensive screening and material selection process is underway for NEXT since the control of the radiopurity levels of the materials to be used in the experimental set-up is a must for rare event searches. First measurements based on Glow Discharge Mass Spectrometry and gamma-ray spectroscopy using ultra-low background germanium detectors at the Laboratorio Subterr and apos;aneo de Canfranc (Spain) are described here. Activity results for natural radioactive chains and other common radionuclides are summarized, being the values obtained for some materials like copper and stainless steel very competitive. The implications of these results for the NEXT experiment are also discussed.
$\\beta$-decay study of neutron-rich Tl and Pb isotopes
It is proposed to study the structure of neutron-rich nuclei beyond $^{208}$Pb. The one-proton hole $^{211-215}$Tl and the semi magic $^{213}$Pb will be produced and studied via nuclear and atomic spectroscopy searching for long-lived isomers and investigating the $\\beta$-delayed $\\gamma$- emission to build level schemes. Information on the single particle structure in $^{211-215}$Pb, especially the position of the g$_{9/2}$ and i$_{11/2}$ neutron orbitals, will be extracted along with lifetimes. The $\\beta$-decay will be complemented with the higher spin selectivity that can be obtained by resonant laser ionization to single-out the decay properties of long-living isomers in $^{211,213}$Tl and $^{213}$Pb.
The Majorana Zero-Neutrino Double-Beta Decay Experiment White Paper
International Nuclear Information System (INIS)
Gaitskell, R.; Barabash, A.; Konovalov, S.; Stekhanov, V.; Umatov, V.; Brudanin, V.; Egorov, S.; Webb, J.; Miley, Harry S.; Aalseth, Craig E.; Anderson, Dale N.; Bowyer, Ted W.; Brodzinski, Ronald L.; Jordan, David B.; Kouzes, Richard T.; Smith, Eric E.; Thompson, Robert C.; Warner, Ray A.; Tornow, W.; Young, A.; Collar, J.I.; Avignone, Frank T.; Palms, John M.; Doe, P J.; Elliott, Steven R.; Kazkaz, K.; Robertson, Hamish; Wilkerson, John
2002-01-01
The goal of the Majorana Experiment is to determine the effective Majorana mass of the electron neutrino. Detection of the neutrino mass implied by oscillation results in within our grasp. This exciting physics goal is best pursued using double-beta decay of germanium because of the historical and emerging advances in eliminating competing signals from radioactive backgrounds. The Majorana Experiment will consist of a large mass of 76Ge in the form of high-resolution detectors deep underground, searching for a sharp peak at the BB endpoint. We present here an overview of the entire project in order to help put in perspective the scope, the level and technical risk, and the readiness of the Collaboration to begin the undertaking
Identification of shell-model states in $^{135}$Sb populated via $\\beta^{-}$ decay of $^{135}$Sn
Shergur, J; Brown, B A; Cederkäll, J; Dillmann, I; Fraile-Prieto, L M; Hoff, P; Joinet, A; Köster, U; Kratz, K L; Pfeiffer, B; Walters, W B; Wöhr, A
2005-01-01
The $\\beta$- decay of $^{135}$Sn was studied at CERN/ISOLDE using a resonance ionization laser ion source and mass separator to achieve elemental and mass selectivity, respectively. $\\gamma$-ray singles and $\\gamma\\gamma$ coincidence spectra were collected as a function of time with the laser on and with the laser off. These data were used to establish the positions of new levels in $^{135}$Sb, including new low-spin states at 440 and 798 keV, which are given tentative spin and parity assignments of 3/2$^{+}$ and 9/2$^{+}$, respectively. The observed levels of $^{135}$Sb are compared with shell-model calculations using different single-particle energies and different interactions.
The NUMEN project: NUclear Matrix Elements for Neutrinoless double beta decay
Cappuzzello, F.; Agodi, C.; Cavallaro, M.; Carbone, D.; Tudisco, S.; Lo Presti, D.; Oliveira, J. R. B.; Finocchiaro, P.; Colonna, M.; Rifuggiato, D.; Calabretta, L.; Calvo, D.; Pandola, L.; Acosta, L.; Auerbach, N.; Bellone, J.; Bijker, R.; Bonanno, D.; Bongiovanni, D.; Borello-Lewin, T.; Boztosun, I.; Brunasso, O.; Burrello, S.; Calabrese, S.; Calanna, A.; Chávez Lomelí, E. R.; D'Agostino, G.; De Faria, P. N.; De Geronimo, G.; Delaunay, F.; Deshmukh, N.; Ferreira, J. L.; Fisichella, M.; Foti, A.; Gallo, G.; Garcia-Tecocoatzi, H.; Greco, V.; Hacisalihoglu, A.; Iazzi, F.; Introzzi, R.; Lanzalone, G.; Lay, J. A.; La Via, F.; Lenske, H.; Linares, R.; Litrico, G.; Longhitano, F.; Lubian, J.; Medina, N. H.; Mendes, D. R.; Moralles, M.; Muoio, A.; Pakou, A.; Petrascu, H.; Pinna, F.; Reito, S.; Russo, A. D.; Russo, G.; Santagati, G.; Santopinto, E.; Santos, R. B. B.; Sgouros, O.; da Silveira, M. A. G.; Solakci, S. O.; Souliotis, G.; Soukeras, V.; Spatafora, A.; Torresi, D.; Magana Vsevolodovna, R.; Yildirim, A.; Zagatto, V. A. B.
2018-05-01
The article describes the main achievements of the NUMEN project together with an updated and detailed overview of the related R&D activities and theoretical developments. NUMEN proposes an innovative technique to access the nuclear matrix elements entering the expression of the lifetime of the double beta decay by cross section measurements of heavy-ion induced Double Charge Exchange (DCE) reactions. Despite the fact that the two processes, namely neutrinoless double beta decay and DCE reactions, are triggered by the weak and strong interaction respectively, important analogies are suggested. The basic point is the coincidence of the initial and final state many-body wave functions in the two types of processes and the formal similarity of the transition operators. First experimental results obtained at the INFN-LNS laboratory for the 40Ca(18O,18Ne)40Ar reaction at 270MeV give an encouraging indication on the capability of the proposed technique to access relevant quantitative information. The main experimental tools for this project are the K800 Superconducting Cyclotron and MAGNEX spectrometer. The former is used for the acceleration of the required high resolution and low emittance heavy-ion beams and the latter is the large acceptance magnetic spectrometer for the detection of the ejectiles. The use of the high-order trajectory reconstruction technique, implemented in MAGNEX, allows to reach the experimental resolution and sensitivity required for the accurate measurement of the DCE cross sections at forward angles. However, the tiny values of such cross sections and the resolution requirements demand beam intensities much larger than those manageable with the present facility. The on-going upgrade of the INFN-LNS facilities in this perspective is part of the NUMEN project and will be discussed in the article.
Probing new physics in the neutrinoless double beta decay using electron angular correlation
Energy Technology Data Exchange (ETDEWEB)
Ali, A. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Borisov, A.V.; Zhuridov, D.V. [Moscow State Univ. (Russian Federation). Faculty of Physics
2007-06-15
The angular correlation of the electrons emitted in the neutrinoless double beta decay (0{nu}2{beta}) is presented using a general Lorentz invariant effective Lagrangian for the leptonic and hadronic charged weak currents. We show that the coefficient K in the angular correlation d{gamma}/dcos {theta} {proportional_to}(1-K cos {theta}) is essentially independent of the nuclear matrix element models and present its numerical values for the five nuclei of interest ({sup 76}Ge, {sup 82}Se, {sup 100}Mo, {sup 130}Te, and {sup 136}Xe), assuming that the 0{nu}2{beta}-decays in these nuclei are induced solely by a light Majorana neutrino, {nu}{sub M}. This coefficient varies between K=0.82 (for the {sup 76}Ge nucleus) and K=0.88 (for the {sup 82}Se and {sup 100}Mo nuclei), calculated taking into account the effects from the nucleon recoil, the S and P-waves for the outgoing electrons and the electron mass. Deviation of K from its values derived here would indicate the presence of New Physics (NP) in addition to a light Majorana neutrino, and we work out the angular coefficients in several {nu}{sub M}+NP scenarios for the {sup 76}Ge nucleus. As an illustration of the correlations among the 0{nu}2{beta} observables (half-life T{sub 1/2}, the coefficient K, and the effective Majorana neutrino mass vertical stroke left angle m right angle vertical stroke) and the parameters of the underlying NP model, we analyze the left-right symmetric models, taking into account current phenomenological bounds on the right-handed W{sub R}-boson mass and the left-right mixing parameter {zeta}. (orig.)
JENDL FP decay data file 2000 and the beta-decay theory
International Nuclear Information System (INIS)
Yoshida, Tadashi; Katakura, Jun Ichi; Tachibana, Takahiro
2002-01-01
JENDL FP Decay Data File 2000 has been developed as one of the special purpose files of the Japanese Evaluated Nuclear Data Library (JENDL), which constitutes a versatile nuclear data basis for science and technology. In the format of ENDF-6 this file includes the decay data for 1087 unstable fission product (FP) nuclides and 142 stable nuclides as their daughters. The primary purpose of this file is to use in the summation calculation of FP decay heat, which plays a critical role in nuclear safety analysis; the loss-of-coolant accident analysis of reactors, for example. The data for a given nuclide are its decay modes, the Q value, the branching ratios, the average energies released in the form of beta- and gamma-rays per decay, and their spectral data. The primary source of the decay data adopted here is the ENSDF (Evaluated Nuclear Structure Data File). The data in ENSDF, however, cover only the measured values. The data of the short-lived nuclides, which are essential for the decay heat calculations at short cooling times, are often fully lacking or incomplete even if they exist. This is mainly because of their short half-life nature. For such nuclides a theoretical model calculation is applied in order to fill the gaps between the true and the experimentally known decay schemes. In practice we have to predict the average decay energies and the spectral data for a lot of short-lived FPs by use of beta-decay theories. Thus the beta-decay theory plays a very important role in generating the FP decay data file
International Nuclear Information System (INIS)
Nicholson, H.W.
1995-07-01
This report describes progress in data analysis for a search for neutrinoless double-beta decay of molybdenum 100 and related work, Brookhaven National Laboratory's Experiment 850 on color transparency, and work on Brookhaven's EVA detector and the Stanford Linear Accelerator Center's B factory experiment. 6 refs
Spectral shapes and a beta-gamma directional correlation in the beta decay of 172Tm (Jpi = 2-)
DEFF Research Database (Denmark)
Gregers Hansen, P.; Loft Nielsen, H.; Wilsky, K.
1966-01-01
The isotope 172Tm populates the 0+, 2+ and 4+ states of the 172Yb ground-state rotational band directly in beta decay. The shapes and intensities of the three beta groups have been measured by means of a six-gap magnetic spectrometer operated in coincidence with a Nal(Tl) crystal. The experimenta...
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.)
International Nuclear Information System (INIS)
Pretzl, K.P.
1987-11-01
The use of superheated superconducting granules as a particle detector is reviewed. Their application for the detection of dark matter, solar neutrinos, monopoles, and double beta decay is described. A status report on the experimental development of these devices is given. (orig.)
Fast-timing studies of nuclei below $^{68}$Ni populated in the $\\beta$-decay of Mn isotopes
Jokinen, A; Simpson, G S; Garcia borge, M J; Koester, U H; Georgiev, G P; Fraile prieto, L M; Aprahamian, A
2008-01-01
We intend to investigate structure of nuclei populated in the $\\beta$-decay of Mn isotopes via the ATD $\\beta\\gamma\\gamma$(t) technique. With this method we will measure dynamic moments in Fe isotopes and their daughters in order to characterize the role of particle-hole excitation across the ${N}$=40 sub-shell closure and the development of collectivity.
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.
Akulov, Y A
2002-01-01
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 (G sub A /G sub V) sub t = -1.2646 +- 0.0035
Majorana bound states in a disordered quantum dot chain
International Nuclear Information System (INIS)
Zhang, P; Nori, Franco
2016-01-01
We study Majorana bound states in a disordered chain of semiconductor quantum dots proximity-coupled to an s -wave superconductor. By calculating its topological quantum number, based on the scattering-matrix method and a tight-binding model, we can identify the topological property of such an inhomogeneous one-dimensional system. We study the robustness of Majorana bound states against disorder in both the spin-independent terms (including the chemical potential and the regular spin-conserving hopping) and the spin-dependent term, i.e., the spin-flip hopping due to the Rashba spin–orbit coupling. We find that the Majorana bound states are not completely immune to the spin-independent disorder, especially when the latter is strong. Meanwhile, the Majorana bound states are relatively robust against spin-dependent disorder, as long as the spin-flip hopping is of uniform sign (i.e., the varying spin-flip hopping term does not change its sign along the chain). Nevertheless, when the disorder induces sign-flip in spin-flip hopping, the topological-nontopological phase transition takes place in the low-chemical-potential region. (paper)
Hyperon polarizabilities in the bound-state soliton model
International Nuclear Information System (INIS)
Gobbi, C.; Scoccola, N.N.
1996-01-01
A detailed calculation of electric and magnetic static polarizabilities of octet hyperons is presented in the framework of the bound-state soliton model. Both seagull and dispersive contributions are considered, and the results are compared with different model predictions. (orig.)
Three-nucleon forces and the trinucleon bound states
International Nuclear Information System (INIS)
Friar, J.L.; Frois, B.
1986-04-01
A summary of the bound-state working group session of the ''International Symposium on the Three-Body Force in the Three-Nucleon System'' is presented. The experimental evidence for three-nucleon forces has centered on two ground state properties: the tritium binding energy and the trinucleon form factors. Both are discussed
Stieltjes electrostatic model interpretation for bound state problems
Indian Academy of Sciences (India)
In this paper, it is shown that Stieltjes electrostatic model and quantum Hamilton Jacobi formalism are analogous to each other. This analogy allows the bound state problem to mimic as unit moving imaginary charges i ℏ , which are placed in between the two fixed imaginary charges arising due to the classical turning ...
On resonances and bound states of Smilansky Hamiltonian
Czech Academy of Sciences Publication Activity Database
Exner, Pavel; Lotoreichik, Vladimir; Tater, Miloš
2016-01-01
Roč. 7, č. 5 (2016), s. 789-802 ISSN 2220-8054 R&D Projects: GA ČR(CZ) GA14-06818S Institutional support: RVO:61389005 Keywords : Smilansky Hamiltonian * resonances * resonance free region * weak coupling asymptotics * Riemann surface * bound states Subject RIV: BE - Theoretical Physics
Microscopic observation of magnon bound states and their dynamics.
Fukuhara, Takeshi; Schauß, Peter; Endres, Manuel; Hild, Sebastian; Cheneau, Marc; Bloch, Immanuel; Gross, Christian
2013-10-03
The existence of bound states of elementary spin waves (magnons) in one-dimensional quantum magnets was predicted almost 80 years ago. Identifying signatures of magnon bound states has so far remained the subject of intense theoretical research, and their detection has proved challenging for experiments. Ultracold atoms offer an ideal setting in which to find such bound states by tracking the spin dynamics with single-spin and single-site resolution following a local excitation. Here we use in situ correlation measurements to observe two-magnon bound states directly in a one-dimensional Heisenberg spin chain comprising ultracold bosonic atoms in an optical lattice. We observe the quantum dynamics of free and bound magnon states through time-resolved measurements of two spin impurities. The increased effective mass of the compound magnon state results in slower spin dynamics as compared to single-magnon excitations. We also determine the decay time of bound magnons, which is probably limited by scattering on thermal fluctuations in the system. Our results provide a new way of studying fundamental properties of quantum magnets and, more generally, properties of interacting impurities in quantum many-body systems.
K-nuclear bound states in a dynamical model
Czech Academy of Sciences Publication Activity Database
Mareš, Jiří; Friedman, E.; Gal, A.
2006-01-01
Roč. 770, 1/2 (2006), s. 84-105 ISSN 0375-9474 Institutional research plan: CEZ:AV0Z10480505 Keywords : kaonic atoms * K-nuclear bound states * K-nucleus interaction Subject RIV: BE - Theoretical Physics Impact factor: 2.155, year: 2006
Quasi-bound states, resonance tunnelling, and tunnelling times ...
Indian Academy of Sciences (India)
analysis of bound states below the threshold energy E = 0 and continuum above the threshold .... p are time reversal states of each other. Similarly, the ... are occurring at above-barrier energies and we do not treat them as QB states. They can ...
Relativistic bound states: a mass formula for vector mesons
International Nuclear Information System (INIS)
Richard, J.L.; Sorba, P.
1975-07-01
In the framework of a relativistic description of two particles bound states, a mass formula for vector mesons considered as quark-antiquark systems bound by harmonic oscillator like forces is proposed. Results in good agreement with experimental values are obtained [fr
Development of segmented germanium detectors for neutrinoless double beta decay experiments
International Nuclear Information System (INIS)
Liu, Jing
2009-01-01
The results from neutrino oscillation experiments indicate that at least two neutrinos have mass. However, the value of the masses and whether neutrinos and anti-neutrinos are identical, i.e., Majorana particles, remain unknown. Neutrinoless double beta decay experiments can help to improve our understanding in both cases and are the only method currently possible to tackle the second question. The GERmanium Detector Array (GERDA) experiment, which will search for the neutrinoless double beta decay of 76 Ge, is currently under construction in Hall A of the INFN Gran Sasso National Laboratory (LNGS), Italy. In order to achieve an extremely low background level, segmented germanium detectors are considered to be operated directly in liquid argon which serves simultaneously as cooling and shielding medium. Several test cryostats were built at the Max-Planck-Institut fuer Physik in Muenchen to operate segmented germanium detectors both in vacuum and submerged in cryogenic liquid. The performance and the background discrimination power of segmented germanium detectors were studied in detail. It was proven for the first time that segmented germanium detectors can be operated stably over long periods submerged in a cryogenic liquid. It was confirmed that the segmentation scheme employed does well in the identification of photon induced background and demonstrated for the first time that also neutron interactions can be identified. The C++ Monte Carlo framework, MaGe (Majorana-GERDA), is a joint development of the Majorana and GERDA collaborations. It is based on GEANT4, but tailored especially to simulate the response of ultra-low background detectors to ionizing radiation. The predictions of the simulation were veri ed to be accurate for a wide range of conditions. Some shortcomings were found and corrected. Pulse shape analysis is complementary to segmentation in identifying background events. Its efficiency can only be correctly determined using reliable pulse shape
Development of segmented germanium detectors for neutrinoless double beta decay experiments
Energy Technology Data Exchange (ETDEWEB)
Liu, Jing
2009-06-09
The results from neutrino oscillation experiments indicate that at least two neutrinos have mass. However, the value of the masses and whether neutrinos and anti-neutrinos are identical, i.e., Majorana particles, remain unknown. Neutrinoless double beta decay experiments can help to improve our understanding in both cases and are the only method currently possible to tackle the second question. The GERmanium Detector Array (GERDA) experiment, which will search for the neutrinoless double beta decay of {sup 76}Ge, is currently under construction in Hall A of the INFN Gran Sasso National Laboratory (LNGS), Italy. In order to achieve an extremely low background level, segmented germanium detectors are considered to be operated directly in liquid argon which serves simultaneously as cooling and shielding medium. Several test cryostats were built at the Max-Planck-Institut fuer Physik in Muenchen to operate segmented germanium detectors both in vacuum and submerged in cryogenic liquid. The performance and the background discrimination power of segmented germanium detectors were studied in detail. It was proven for the first time that segmented germanium detectors can be operated stably over long periods submerged in a cryogenic liquid. It was confirmed that the segmentation scheme employed does well in the identification of photon induced background and demonstrated for the first time that also neutron interactions can be identified. The C++ Monte Carlo framework, MaGe (Majorana-GERDA), is a joint development of the Majorana and GERDA collaborations. It is based on GEANT4, but tailored especially to simulate the response of ultra-low background detectors to ionizing radiation. The predictions of the simulation were veri ed to be accurate for a wide range of conditions. Some shortcomings were found and corrected. Pulse shape analysis is complementary to segmentation in identifying background events. Its efficiency can only be correctly determined using reliable pulse
Atomic effects of beta decay in astrophysics and in elementary particle physics
International Nuclear Information System (INIS)
Zonghua, Chen.
1988-01-01
The thesis consists mainly of two parts. The first part is a study of the bound-state β decay of 187 Re and its application in Astrophysics. There existed an uncertainty in the ratio ρ b of bound-state to continuum β decay of 187 Re in both theory and experiment. A more definite theoretical result of ρ b ∼ 1% is obtained by using single-configuration and multi-configuration Hartree-Fock-Dirac approximations. The results obtained are close to those obtained by Williams, Fowler, and Koonin by a modified Thomas-Fermi model. The bound-state β decay of 187 Re at high temperatures is also studied. The second part of the thesis is a generalization of the Thomas-Fermi results of various energy contribution to the ground-state energy of a neutral atom. An analytical expression for the ratio of the electron-electron to electron-nuclear interaction is obtained by the corrected Thomas-Fermi result, the ratio obtained gives a better agreement with the Hartree-Fock numerical results
Bound states and scattering in four-body systems
International Nuclear Information System (INIS)
Narodetsky, I.M.
1979-01-01
It is the purpose of this review to provide the clear and elementary introduction in the integral equation method and to demonstrate explicitely its usefulness for the physical applications. The existing results concerning the application of the integral equation technique for the four-nucleon bound states and scattering are reviewed.The treatment is based on the quasiparticle approach that permits the simple interpretation of the equations in terms of quasiparticle scattering. The mathematical basis for the quasiparticle approach is the Hilbert-Schmidt theorem of the Fredholm integral equation theory. This paper contains the detailed discussion of the Hilbert-Schmidt expansion as applied to the 2-particle amplitudes and to the 3 + 1 and 2 + 2 amplitudes which are the kernels of the four-body equations. The review contains essentially the discussion of the four-body quasiparticle equations and results obtained for bound states and scattering
Possible Existence of (cc¯)–Nucleus Bound States
International Nuclear Information System (INIS)
Yokota, Akira; Oka, Makoto; Hiyama, Emiko
2014-01-01
Charmonium (cc¯) bound states in few-nucleon systems, 2 H, 4 He and 8 Be, are studied via Gaussian Expansion Method (GEM). We adopt a Gaussian potential as an effective (cc¯)–nucleon (N) interaction. The relation between two-body (cc¯)–N scattering length a cc¯−N and the binding energies B of (cc¯)–nucleus bound states are given. Recent lattice QCD data of a cc¯−N corresponds to B≃0.5 MeV for (cc¯)− 4 He and 2 MeV for (cc¯)− 8 Be in our results. (author)
Bound states in strongly correlated magnetic and electronic systems
International Nuclear Information System (INIS)
Trebst, S.
2002-02-01
A novel strong coupling expansion method to calculate two-particle spectra of quantum lattice models is developed. The technique can be used to study bosonic and fermionic models and in principle it can be applied to systems in any dimension. A number of strongly correlated magnetic and electronic systems are examined including the two-leg spin-half Heisenberg ladder, the dimerized Heisenberg chain with a frustrating next-nearest neighbor interaction, coupled Heisenberg ladders, and the one-dimensional Kondo lattice model. In the various models distinct bound states are found below the two-particle continuum. Quantitative calculations of the dispersion, coherence length and binding energy of these bound states are used to describe spectroscopic experiments on (Ca,La) 14 Cu 24 O 41 and NaV 2 O 5 . (orig.)
Probing Andreev bound states in one-atom superconducting contacts
Energy Technology Data Exchange (ETDEWEB)
Pothier, Hugues; Janvier, Camille; Tosi, Leandro; Girit, Caglar; Goffman, Marcelo; Esteve, Daniel; Urbina, Cristian [Quantronics Group, SPEC, CEA-Saclay (France)
2015-07-01
Superconductors are characterized by a dissipationless current. Since the work of Josephson 50 years ago, it is known that a supercurrent can even flow through tunnel junctions between superconductors. This Josephson effect also occurs through any type of ''weak links'' between superconductors: non-superconducting materials, constrictions,.. A unified understanding of the Josephson effect has emerged from a mesoscopic description of weak links. It relies on the existence of doublets of localized states that have energies below the superconducting gap: the Andreev bound states. I will present experiments performed on the simplest conductor possible, a single-atom contact between superconductors, that illustrate these concepts. The most recent work demonstrates time-domain manipulation of quantum superpositions of Andreev bound states.
R-matrix calculations for few-quark bound states
International Nuclear Information System (INIS)
Shalchi, M.A.; Hadizadeh, M.R.
2016-01-01
The R-matrix method is implemented to study the heavy charm and bottom diquark, triquark, tetraquark, and pentaquarks in configuration space, as the bound states of quark-antiquark, diquark-quark, diquark-antidiquark, and diquark-antitriquark systems, respectively. The mass spectrum and the size of these systems are calculated for different partial wave channels. The calculated masses are compared with recent theoretical results obtained by other methods in momentum and configuration spaces and also by available experimental data. (orig.)
Localized bound states of fermions interacting via massive vector bosons
International Nuclear Information System (INIS)
Ionescu, D.C.; Reinhardt, J.; Mueller, B.; Greiner, W.; Soff, G.
1988-11-01
A model for composite consisting of fermions with internal degrees of freedom interacting via intermediate vector bosons (IVB) is constructed. We find highly localized, low-mass bound states in the Hartree-Fock approximation. We investigate the dependence of these states as function of the coupling constant and vector boson mass. In the limit of infinite vector boson mass the interaction is described by Fermi-type contact forces. (orig.)
Parity lifetime of bound states in a proximitized semiconductor nanowire
DEFF Research Database (Denmark)
Higginbotham, Andrew Patrick; Albrecht, Sven Marian; Kirsanskas, Gediminas
2015-01-01
Quasiparticle excitations can compromise the performance of superconducting devices, causing high frequency dissipation, decoherence in Josephson qubits, and braiding errors in proposed Majorana-based topological quantum computers. Quasiparticle dynamics have been studied in detail in metallic...... superconductor layer, yielding an isolated, proximitized nanowire segment. We identify Andreev-like bound states in the semiconductor via bias spectroscopy, determine the characteristic temperatures and magnetic fields for quasiparticle excitations, and extract a parity lifetime (poisoning time) of the bound...
QCD bound states at finite temperature and baryon number
International Nuclear Information System (INIS)
Kalinovsky, Yu.L.; Muenchow, L.
1991-04-01
Quark-antiquark bound states are described within the Bethe-Salpeter equation for a class of quark models with instantaneous 4-quark interaction at finite temperature. Thereby decompositions of the Bethe-Salpeter vertex and wave functions according to their Lorentz structures and the particles content are used. As an application of general scheme, we determine the mass spectrum of low-lying mesons for a special Nambu-Jona-Lasinio model inspired by QCD for hadrons. (orig.)
Improved Rosen's conditions on bound states of Schroedinger operators
International Nuclear Information System (INIS)
Exner, P.
1984-01-01
We derive a necessary condition on a Schroedinger operator H=-Δ+V on Lsup(2)(Rsup(d)), d>=3 to have a bound state below a given energy epsilon, and a lower bound to the ground-state energy of H. These conditions are expressed in terms of the potential V alone, and generalize the recent results of Rosen to the dimensions d>3 and to the potentials that are not necessarily rapidly decreasing. Some examples are given
Relativistic treatment of fermion-antifermion bound states
International Nuclear Information System (INIS)
Lucha, W.; Rupprecht, H.; Schoeberl, F.F.
1990-01-01
We discuss the relativistic treatment of fermion-antifermion bound states by an effective-Hamiltonian method which imitates their description in terms of nonrelativistic potential models: the effective interaction potential, to be used in a Schroedinger equation which incorporates relativistic kinematics, is derived from the underlying quantum field theory. This approach is equivalent to the instantaneous approximation to the Bethe-Salpeter equation called Salpeter equation but comes closer to physical intuition than the latter one. (Author) 14 refs
Shell-model calculations of beta-decay rates for s- and r-process nucleosyntheses
International Nuclear Information System (INIS)
Takahashi, K.; Mathews, G.J.; Bloom, S.D.
1985-01-01
Examples of large-basis shell-model calculations of Gamow-Teller β-decay properties of specific interest in the astrophysical s- and r- processes are presented. Numerical results are given for: (1) the GT-matrix elements for the excited state decays of the unstable s-process nucleus 99 Tc; and (2) the GT-strength function for the neutron-rich nucleus 130 Cd, which lies on the r-process path. The results are discussed in conjunction with the astrophysics problems. 23 refs., 3 figs
The number of bound states for a discrete Schroedinger operator on ZN, N≥1, lattices
International Nuclear Information System (INIS)
Karachalios, N I
2008-01-01
We consider the discrete Schroedinger operator -Δ d +U in Z N , N≥1 in the case of a potential with negative part in an appropriate l σ -space (decays with an appropriate rate). We present a discrete analog of the method of Li and Yau (1983 Commun. Math. Phys. 88 309-18), proving an explicit upper estimate on the number of bound states N d (0)={j:μ j ≤0}, which is independent of the dimension of the lattice. This is a major difference with the continuous counterpart estimate, which is not valid when N = 1, 2. As a consequence, a dimension-independent smallness criterion for the existence of bound states is derived in contrast to the continuous case as well as to the discrete case of vanishing potential. A short comment is made on possible applications of the results to the study of the dynamics of some particular spatially discrete nonlinear systems
Two-nucleon bound states in quenched lattice QCD
International Nuclear Information System (INIS)
Yamazaki, T.; Kuramashi, Y.; Ukawa, A.
2011-01-01
We address the issue of bound state in the two-nucleon system in lattice QCD. Our study is made in the quenched approximation at the lattice spacing of a=0.128 fm with a heavy quark mass corresponding to m π =0.8 GeV. To distinguish a bound state from an attractive scattering state, we investigate the volume dependence of the energy difference between the ground state and the free two-nucleon state by changing the spatial extent of the lattice from 3.1 fm to 12.3 fm. A finite energy difference left in the infinite spatial volume limit leads us to the conclusion that the measured ground states for not only spin triplet but also singlet channels are bounded. Furthermore the existence of the bound state is confirmed by investigating the properties of the energy for the first excited state obtained by a 2x2 diagonalization method. The scattering lengths for both channels are evaluated by applying the finite volume formula derived by Luescher to the energy of the first excited states.
Volume dependence of N-body bound states
König, Sebastian; Lee, Dean
2018-04-01
We derive the finite-volume correction to the binding energy of an N-particle quantum bound state in a cubic periodic volume. Our results are applicable to bound states with arbitrary composition and total angular momentum, and in any number of spatial dimensions. The only assumptions are that the interactions have finite range. The finite-volume correction is a sum of contributions from all possible breakup channels. In the case where the separation is into two bound clusters, our result gives the leading volume dependence up to exponentially small corrections. If the separation is into three or more clusters, there is a power-law factor that is beyond the scope of this work, however our result again determines the leading exponential dependence. We also present two independent methods that use finite-volume data to determine asymptotic normalization coefficients. The coefficients are useful to determine low-energy capture reactions into weakly bound states relevant for nuclear astrophysics. Using the techniques introduced here, one can even extract the infinite-volume energy limit using data from a single-volume calculation. The derived relations are tested using several exactly solvable systems and numerical examples. We anticipate immediate applications to lattice calculations of hadronic, nuclear, and cold atomic systems.
Shooting quasiparticles from Andreev bound states in a superconducting constriction
Energy Technology Data Exchange (ETDEWEB)
Riwar, R.-P.; Houzet, M.; Meyer, J. S. [University of Grenoble Alpes, INAC-SPSMS (France); Nazarov, Y. V., E-mail: Y.V.Nazarov@tudelft.nl [Delft University of Technology, Kavli Institute of NanoScience (Netherlands)
2014-12-15
A few-channel superconducting constriction provides a set of discrete Andreev bound states that may be populated with quasiparticles. Motivated by recent experimental research, we study the processes in an a.c. driven constriction whereby a quasiparticle is promoted to the delocalized states outside the superconducting gap and flies away. We distinguish two processes of this kind. In the process of ionization, a quasiparticle present in the Andreev bound state is transferred to the delocalized states leaving the constriction. The refill process involves two quasiparticles: one flies away while another one appears in the Andreev bound state. We notice an interesting asymmetry of these processes. The electron-like quasiparticles are predominantly emitted to one side of the constriction while the hole-like ones are emitted to the other side. This produces a charge imbalance of accumulated quasiparticles, that is opposite on opposite sides of the junction. The imbalance may be detected with a tunnel contact to a normal metal lead.
Pulse-shape discrimination techniques for the COBRA double beta-decay experiment at LNGS
Zatschler, S.; COBRA Collaboration
2017-09-01
In modern elementary particle physics several questions arise from the fact that neutrino oscillation experiments have found neutrinos to be massive. Among them is the so far unknown nature of neutrinos: either they act as so-called Majorana particles, where one cannot distinguish between particle and antiparticle, or they are Dirac particles like all the other fermions in the Standard Model. The study of neutrinoless double beta-decay (0νββ-decay), where the lepton number conservation is violated by two units, could answer the question regarding the underlying nature of neutrinos and might also shed light on the mechanism responsible for the mass generation. So far there is no experimental evidence for the existence of 0νββ-decay, hence, existing experiments have to be improved and novel techniques should be explored. One of the next-generation experiments dedicated to the search for this ultra-rare decay is the COBRA experiment. This article gives an overview of techniques to identify and reject background based on pulse-shape discrimination.
Beta-decay and decay heat. Summary report of consultants' meeting
International Nuclear Information System (INIS)
Nicols, A.L.
2006-01-01
Experts on decay data and decay heat calculations participated in a Consultants' Meeting organized at IAEA Headquarters on 12-14 December 2005. Debate focused on the validation of decay heat calculations as a function of cooling time for fuel irradiated in power reactors through comparisons with experimental benchmark data. Both the current understanding and quantification of mean beta and gamma decay energies were reviewed with respect to measurements and the Gross Theory of Beta Decay. Particular emphasis was placed on the known development of total absorption gamma-ray spectroscopy (TAGS), and detailed discussions took place to formulate the measurement requirements for mean beta and gamma data of individual radionuclides. This meeting was organized in cooperation with the OECD/NEA Working Party for Evaluation and Cooperation (WPEC). Proposals and recommendations were made to resolve particular difficulties, and an initial list of fission products was produced for TAGS studies. The discussions, conclusions and recommendations of the meeting are briefly described in this report. (author)
The slow control system of the GERDA double beta decay experiment at Gran Sasso
International Nuclear Information System (INIS)
Brugnera, R; Garfagnini, A; Gigante, G; Hemmer, S; Zinato, D; Costa, F; Lippi, I; Michelotto, M; Ur, C
2012-01-01
GERDA is an experiment designed and built to study double beta decays of 76 Ge. It is currently in operation at the Gran Sasso underground laboratories (LNGS). A custom slow control system has been designed to monitor and control all the critical parameters for the proper functioning of the experiment. The main sub-components of the experiment (Cryostat, Clean Room, Water Tank, electronic crates and temperatures, High Voltage Systems, Radon Monitor and Source Insertion System) are constantly monitored by several distributed clients which write acquired data to a relational database (PostgreSQL). The latter allows to maintain a history of the whole experiment and, performing correlation between different and independent components, is useful to debug possible system malfunctions. The system is complemented by a Web server, a lightweight and efficient interface to the user on shifts and to the on-call experts, and by a dedicated Alarm dispatcher which distributes the errors generated by the components to the users allowing to react in short time. The whole project has been built around open source and custom software.
MAJORANA Neutrinoless Double-Beta Decay DUSEL R and D. Final report
International Nuclear Information System (INIS)
Wilkerson, John F.
2009-01-01
The Majorana research and development is addressing key issues and risks related to the collaboration's goal of undertaking a search for neutrinoless double-beta decay (0νββ) in 76 Ge using an array of hyper-pure Ge-diodes (HPGe). The observation of this decay would provide critical insight into our understanding of neutrinos, yielding definitive evidence that neutrinos are Majorana particles and providing information on the absolute mass of neutrinos. Achieving sensitivities to 0νββ decay half-lives on the order of 10 26 years requires ultra-low backgrounds in the 2039 keV region where a 0νββ decay peak would be observed. The goal of our R and D program has been to demonstrate the feasibility of all components of Majorana and to provide an integrated evaluation framework, allowing for optimization of these components in terms of background, background suppression, and signal detection efficiency and acceptance. This report covers work carried out by Majorana collaboration members at the University of Washington as part of the overall Majorana collaboration activities. Specifically the Majorana group at the University of Washington was involved in moving forward on demonstrating technology for clean large-scale cryostats and mounting the HPGe crystals in low-mass holders. The UW activities included assistance in the procurement and assembly of an electroforming system for large size cryostats, and design and fabrication of prototype crystal mounting hardware.
Beta decays of 126Cd and 126In to levels in 126In and 126Sn
International Nuclear Information System (INIS)
Gartner, M.L.
1979-01-01
A study of the beta decays of 126 Cd and 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 126 Cd was determined to be 0.506 +- 0.015 sec., and the half-lives for the low- and high-spin 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 126 Cd, and all but one were placed in a level scheme for 126 In. A total of 48 gamma rays were observed in the decay of the low- and high-spin 126 In isomers and all were placed in a level scheme for 126 Sn. Spin and parity assignments were deduced, whenever possible, on the basis of logft values and gamma decay selection rules. The 126 In decay schemes (one has been proposed for each isomer) are compared with earlier decay studies and with results from 124 Sn(t,p) 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
Energy Technology Data Exchange (ETDEWEB)
Liao, Heng-Ye [Max-Planck-Institut fuer Physik, Muenchen (Germany); Collaboration: GERDA-Collaboration
2013-07-01
The Gerda (GERmanium Detector Array) experiment was built to study fundamental neutrino properties via neutrinoless double beta decay (0νββ). 0νββ events are single-site events (SSE) confined to a scale about millimeter. However, most of backgrounds are multi-site events (MSE). Broad Energy Germanium detectors (BEGes) offer the potential merits of improved pulse shape recognition efficiencies of SSE/MSE. They allow us to reach the goal of Phase II with a background index of 10{sup -3} cts/(keV.kg.yr) in the ROI. BEGe detectors with a total target mass of 3.63 kg have been installed to the Gerda setup in the Laboratori Nazionali del Gran Sasso (LNGS) in July 2012 and are collecting data since. A consistency check of the pulse shape discrimination (PSD) efficiencies by comparison of calibration data and 2νββ data will be presented. The PSD power of these detectors is demonstrated.
Double-beta decay with majoron emission in GERDA Phase I
Hemmer, Sabine
2015-07-01
Neutrinoless double-beta decay with emission of one or two majorons (0 νββχ( χ)) is predicted by several beyond-Standard-Model theories. This article reviews the results of a search for 0 νββχ( χ) of 76Ge using data from the Germanium Detector Array (GERDA) experiment, located underground at the INFN Laboratori Nazionali del Gran Sasso (LNGS) in Italy. The analysis comprised data with an exposure of 20.3 kg·yr from the first phase of the experiment. No indication of contributions to the observed energy spectra was detected for any of the majoron models. The lower limit on the half-life for the ordinary majoron model (spectral index n = 1 was determined to be T {1/2/0 νβ } > 4.2 · 1023 yr (90% quantile). This limit and the limits derived for the other majoron modes constitute the most stringent limits on 0 νββχ( χ) decay of 76Ge measured to date.
The large enriched germanium experiment for neutrinoless double beta decay (LEGEND)
Abgrall, N.; Abramov, A.; Abrosimov, N.; Abt, I.; Agostini, M.; Agartioglu, M.; Ajjaq, A.; Alvis, S. I.; Avignone, F. T.; Bai, X.; Balata, M.; Barabanov, I.; Barabash, A. S.; Barton, P. J.; Baudis, L.; Bezrukov, L.; Bode, T.; Bolozdynya, A.; Borowicz, D.; Boston, A.; Boston, H.; Boyd, S. T. P.; Breier, R.; Brudanin, V.; Brugnera, R.; Busch, M.; Buuck, M.; Caldwell, A.; Caldwell, T. S.; Camellato, T.; Carpenter, M.; Cattadori, C.; Cederkäll, J.; Chan, Y.-D.; Chen, S.; Chernogorov, A.; Christofferson, C. D.; Chu, P.-H.; Cooper, R. J.; Cuesta, C.; Demidova, E. V.; Deng, Z.; Deniz, M.; Detwiler, J. A.; Di Marco, N.; Domula, A.; Du, Q.; Efremenko, Yu.; Egorov, V.; Elliott, S. R.; Fields, D.; Fischer, F.; Galindo-Uribarri, A.; Gangapshev, A.; Garfagnini, A.; Gilliss, T.; Giordano, M.; Giovanetti, G. K.; Gold, M.; Golubev, P.; Gooch, C.; Grabmayr, P.; Green, M. P.; Gruszko, J.; Guinn, I. S.; Guiseppe, V. E.; Gurentsov, V.; Gurov, Y.; Gusev, K.; Hakenmüeller, J.; Harkness-Brennan, L.; Harvey, Z. R.; Haufe, C. R.; Hauertmann, L.; Heglund, D.; Hehn, L.; Heinz, A.; Hiller, R.; Hinton, J.; Hodak, R.; Hofmann, W.; Howard, S.; Howe, M. A.; Hult, M.; Inzhechik, L. V.; Csáthy, J. Janicskó; Janssens, R.; Ješkovský, M.; Jochum, J.; Johansson, H. T.; Judson, D.; Junker, M.; Kaizer, J.; Kang, K.; Kazalov, V.; Kermadic, Y.; Kiessling, F.; Kirsch, A.; Kish, A.; Klimenko, A.; Knöpfle, K. T.; Kochetov, O.; Konovalov, S. I.; Kontul, I.; Kornoukhov, V. N.; Kraetzschmar, T.; Kröninger, K.; Kumar, A.; Kuzminov, V. V.; Lang, K.; Laubenstein, M.; Lazzaro, A.; Li, Y. L.; Li, Y.-Y.; Li, H. B.; Lin, S. T.; Lindner, M.; Lippi, I.; Liu, S. K.; Liu, X.; Liu, J.; Loomba, D.; Lubashevskiy, A.; Lubsandorzhiev, B.; Lutter, G.; Ma, H.; Majorovits, B.; Mamedov, F.; Martin, R. D.; Massarczyk, R.; Matthews, J. A. J.; McFadden, N.; Mei, D.-M.; Mei, H.; Meijer, S. J.; Mengoni, D.; Mertens, S.; Miller, W.; Miloradovic, M.; Mingazheva, R.; Misiaszek, M.; Moseev, P.; Myslik, J.; Nemchenok, I.; Nilsson, T.; Nolan, P.; O'Shaughnessy, C.; Othman, G.; Panas, K.; Pandola, L.; Papp, L.; Pelczar, K.; Peterson, D.; Pettus, W.; Poon, A. W. P.; Povinec, P. P.; Pullia, A.; Quintana, X. C.; Radford, D. C.; Rager, J.; Ransom, C.; Recchia, F.; Reine, A. L.; Riboldi, S.; Rielage, K.; Rozov, S.; Rouf, N. W.; Rukhadze, E.; Rumyantseva, N.; Saakyan, R.; Sala, E.; Salamida, F.; Sandukovsky, V.; Savard, G.; Schönert, S.; Schütz, A.-K.; Schulz, O.; Schuster, M.; Schwingenheuer, B.; Selivanenko, O.; Sevda, B.; Shanks, B.; Shevchik, E.; Shirchenko, M.; Simkovic, F.; Singh, L.; Singh, V.; Skorokhvatov, M.; Smolek, K.; Smolnikov, A.; Sonay, A.; Spavorova, M.; Stekl, I.; Stukov, D.; Tedeschi, D.; Thompson, J.; Van Wechel, T.; Varner, R. L.; Vasenko, A. A.; Vasilyev, S.; Veresnikova, A.; Vetter, K.; von Sturm, K.; Vorren, K.; Wagner, M.; Wang, G.-J.; Waters, D.; Wei, W.-Z.; Wester, T.; White, B. R.; Wiesinger, C.; Wilkerson, J. F.; Willers, M.; Wiseman, C.; Wojcik, M.; Wong, H. T.; Wyenberg, J.; Xu, W.; Yakushev, E.; Yang, G.; Yu, C.-H.; Yue, Q.; Yumatov, V.; Zeman, J.; Zeng, Z.; Zhitnikov, I.; Zhu, B.; Zinatulina, D.; Zschocke, A.; Zsigmond, A. J.; Zuber, K.; Zuzel, G.
2017-10-01
The observation of neutrinoless double-beta decay (0νββ) would show that lepton number is violated, reveal that neu-trinos are Majorana particles, and provide information on neutrino mass. A discovery-capable experiment covering the inverted ordering region, with effective Majorana neutrino masses of 15 - 50 meV, will require a tonne-scale experiment with excellent energy resolution and extremely low backgrounds, at the level of ˜0.1 count /(FWHM.t.yr) in the region of the signal. The current generation 76Ge experiments GERDA and the Majorana Demonstrator, utilizing high purity Germanium detectors with an intrinsic energy resolution of 0.12%, have achieved the lowest backgrounds by over an order of magnitude in the 0νββ signal region of all 0νββ experiments. Building on this success, the LEGEND collaboration has been formed to pursue a tonne-scale 76Ge experiment. The collaboration aims to develop a phased 0νββ experimental program with discovery potential at a half-life approaching or at 1028 years, using existing resources as appropriate to expedite physics results.
LBL/UCSB 76Ge double beta decay experiment: first results
International Nuclear Information System (INIS)
Goulding, F.S.; Cork, C.P.; Landis, D.A.
1984-10-01
A paper given at the IEEE Nuclear Science Symposium last year presented the scientific justification for this experiment and discussed the design of the detector system. At the present time two of the dual detector systems (i.e., four out of a final total of eight detectors) are operating in the complete active/passive shield in the low background laboratory at LBL. Early results (1620 h) of an experiment using two detectors yield a limit of 4 x 10 22 years (68% confidence) for the half life of the neutrinoless double beta decay (ββ/sub o nu/) of 76 Ge. Although this experiment was carried out above ground, the result approaches those achieved by other groups in deep underground laboratories. Based on studies of the origins of background in our system, we hope to reach a limit of 3 x 10 23 years (or more) in a two month/four detector experiment to be carried out soon in an underground facility
Limits on neutrino-less double beta decay of 100Mo
International Nuclear Information System (INIS)
Ejiri, H.; Fushimi, K.; Hayashi, K.; Kishimoto, T.; Kudomi, N.; Ohsumi, H.; Okada, K.; Shima, T.; Tanaka, J.
1996-01-01
Exclusive measurements of neutrino-less double beta decays (0νββ) of 100 Mo were made by means of ELEGANT V. Most stringent lower limits on the half-lives for the ground-state transition were obtained for the 0νββ processes as T 1/2 0ν (m ν ) > 5.2 x 10 22 y, T 1/2 0ν (λ) > 3.9 x 10 22 y and T 1/2 0ν (η) > 5.1 x 10 22 y, for the mass term left angle m ν right angle, for the right-handed current terms of left angle λ right angle and left angle η right angle, respectively, and as T 1/2 0νB > 5.4 x 10 21 y for the process (0νββB) followed by a Majoron (B). These limits lead to the upper limits of left angle m ν right angle -6 , left angle η right angle -8 and left angle g B right angle -5 with g B being the coupling of B with the neutrino field. Limits on other possible processes beyond the standard theory are discussed. (orig.)
A scintillating bolometer array for double beta decay studies: The LUCIFER experiment
Energy Technology Data Exchange (ETDEWEB)
Gironi, L., E-mail: luca.gironi@mib.infn.it [Università degli Studi di Milano-Bicocca, Milano (Italy); INFN – Sezione di Milano-Bicocca, Milano (Italy)
2016-07-11
The main goal of the LUCIFER experiment is to study the neutrinoless double beta decay, a rare process allowed if neutrinos are Majorana particles. Although aiming at a discovery, in the case of insufficient sensitivity the LUCIFER technique will be the demonstrator for a higher mass experiment able to probe the entire inverted hierarchy region of the neutrino mass. In order to achieve this challenging result, high resolution detectors with active background discrimination capability are required. This very interesting possibility can be largely fulfilled by scintillating bolometers thanks to the simultaneous read-out of heat and light emitted by the interactions in the detector or by pulse shape analysis. - Highlights: • The LUCIFER technique will be the demonstrator for a higher mass experiment. • Scintillating bolometers allow high energy resolution and background discrimination. • The first choice for the LUCIFER tower are ZnSe crystals. • The LUCIFER setup will consist of an array of 30 individual single module detectors. • An array of ZnMoO4 crystals allowed the bolometric observation of the 2vDBD of {sup 100}Mo.
LUCIFER: Scintillating bolometers for the search of Neutrinoless Double Beta Decay
Energy Technology Data Exchange (ETDEWEB)
Vignati, M. [Sapienza Universita di Roma and INFN Sezione di Roma, Roma, I-00185 (Italy)
2012-08-15
The nature of neutrino mass is one of the frontier problems of particle physics. Neutrinoless Double Beta Decay (0{nu}DBD) is a powerful tool to measure the neutrino mass and to test possible extensions of the Standard Model. Bolometers are excellent detectors to search for this rare decay, thanks to their good energy resolution and to the low background conditions in which they can operate. The current challenge consists in the reduction of the background, represented by environmental {gamma}'s and {alpha}'s, in view of a zero background experiment. We present the LUCIFER R and D, funded by an European grant, in which the background can be reduced by an order of magnitude with respect to the present generation experiments. The technique is based on the simultaneous bolometric measurement of the heat and of the scintillation light produced by a particle, that allows to discriminate between {beta} and {alpha} particles. The {gamma} background is reduced by choosing 0{nu}DBD candidate isotopes with transition energy above the environmental {gamma}'s spectrum. The prospect of this R and D are discussed.
Directory of Open Access Journals (Sweden)
Tenconi M.
2014-01-01
Full Text Available As proposed in the LUCIFER project, ZnSe crystals are attractive materials to realize scintillating bolometers aiming at the search for neutrinoless double beta decay of the promising isotope 82Se. However, the optimization of the ZnSe-based detectors is rather complex and requires a wide-range investigation of the crystal features: optical properties, crystalline quality, scintillation yields and bolometric behaviour. Samples tested up to now show problems in the reproducibility of crucial aspects of the detector performance. In this work, we present the results obtained with a scintillating bolometer operated aboveground at about 25 mK. The detector energy absorber was a single 1 cm3 ZnSe crystal. The good energy resolution of the heat channel (about 14 keV at 1460 keV and the excellent alpha/beta discrimination capability are very encouraging for a successful realization of the LUCIFER program. The bolometric measurements were completed by optical tests on the crystal (optical transmission and luminescence measurements down to 10 K and investigation of the crystalline structure. The work here described provides a set of parameters and procedures useful for a complete pre-characterization of ZnSe crystals in view of the realization of highly performing scintillating bolometers.
Measuring nuclear reaction cross sections to extract information on neutrinoless double beta decay
Cavallaro, M.; Cappuzzello, F.; Agodi, C.; Acosta, L.; Auerbach, N.; Bellone, J.; Bijker, R.; Bonanno, D.; Bongiovanni, D.; Borello-Lewin, T.; Boztosun, I.; Branchina, V.; Bussa, M. P.; Calabrese, S.; Calabretta, L.; Calanna, A.; Calvo, D.; Carbone, D.; Chávez Lomelí, E. R.; Coban, A.; Colonna, M.; D'Agostino, G.; De Geronimo, G.; Delaunay, F.; Deshmukh, N.; de Faria, P. N.; Ferraresi, C.; Ferreira, J. L.; Finocchiaro, P.; Fisichella, M.; Foti, A.; Gallo, G.; Garcia, U.; Giraudo, G.; Greco, V.; Hacisalihoglu, A.; Kotila, J.; Iazzi, F.; Introzzi, R.; Lanzalone, G.; Lavagno, A.; La Via, F.; Lay, J. A.; Lenske, H.; Linares, R.; Litrico, G.; Longhitano, F.; Lo Presti, D.; Lubian, J.; Medina, N.; Mendes, D. R.; Muoio, A.; Oliveira, J. R. B.; Pakou, A.; Pandola, L.; Petrascu, H.; Pinna, F.; Reito, S.; Rifuggiato, D.; Rodrigues, M. R. D.; Russo, A. D.; Russo, G.; Santagati, G.; Santopinto, E.; Sgouros, O.; Solakci, S. O.; Souliotis, G.; Soukeras, V.; Spatafora, A.; Torresi, D.; Tudisco, S.; Vsevolodovna, R. I. M.; Wheadon, R. J.; Yildirin, A.; Zagatto, V. A. B.
2018-02-01
Neutrinoless double beta decay (0vββ) is considered the best potential resource to access the absolute neutrino mass scale. Moreover, if observed, it will signal that neutrinos are their own anti-particles (Majorana particles). Presently, this physics case is one of the most important research “beyond Standard Model” and might guide the way towards a Grand Unified Theory of fundamental interactions. Since the 0vββ decay process involves nuclei, its analysis necessarily implies nuclear structure issues. In the NURE project, supported by a Starting Grant of the European Research Council (ERC), nuclear reactions of double charge-exchange (DCE) are used as a tool to extract information on the 0vββ Nuclear Matrix Elements. In DCE reactions and ββ decay indeed the initial and final nuclear states are the same and the transition operators have similar structure. Thus the measurement of the DCE absolute cross-sections can give crucial information on ββ matrix elements. In a wider view, the NUMEN international collaboration plans a major upgrade of the INFN-LNS facilities in the next years in order to increase the experimental production of nuclei of at least two orders of magnitude, thus making feasible a systematic study of all the cases of interest as candidates for 0vββ.
Search for Correlated Fluctuations in the Beta+ Decay of Na-22
Silverman, M. P.; Strange, W.
2008-10-01
Claims for a ``cosmogenic'' force that correlates otherwise independent stochastic events have been made for at least 10 years, based largely on visual inspection of time series of histograms whose shapes were interpreted as suggestive of recurrent patterns with semi-diurnal, diurnal, and monthly periods. Building on our earlier work to test randomness of different nuclear decay processes, we have searched for correlations in the time-series of coincident positron-electron annihilations deriving from beta+ decay of Na-22. Disintegrations were counted within a narrow time window over a period of 7 days, leading to a time series of more than 1 million events. Statistical tests were performed on the raw time series, its correlation function, and its Fourier transform to search for cyclic correlations indicative of quantum-mechanical violating deviations from Poisson statistics. The time series was then partitioned into a sequence of 167 ``bags'' each of 8192 events. A histogram was made of the events of each bag, where contiguous frequency classes differed by a single count. The chronological sequence of histograms was then tested for correlations within classes. In all cases the results of the tests were in accord with statistical control, giving no evidence of correlated fluctuations.
Results of a search for neutrinoless double-beta decay using the COBRA demonstrator
Energy Technology Data Exchange (ETDEWEB)
Quante, Thomas; Goessling, Claus; Kroeninger, Kevin [TU Dortmund, Exp. Physik IV, Dortmund (Germany)
2016-07-01
COBRA is an experiment aiming to search for neutrinoless double-beta-decay (0νββ-decay) using CdZnTe semiconductor detectors. The main focus is on {sup 116}Cd, with a Q-value of 2813.5 keV well above the highest dominant naturally occurring gamma lines. By measuring the half-life of the 0νββ-decay, it is possible to clarify the nature of the neutrino as either Dirac or Majorana particle and furthermore to determine its effective Majorana mass. The COBRA collaboration operates a demonstrator to search for these decays at the Laboratori Nazionali del Gran Sasso in Italy. The exposure of 234.7 kg d considered in this analysis was collected between September 2011 and February 2015. The analysis focuses on the decay of the nuclides {sup 114}Cd, {sup 128}Te, {sup 70}Zn, {sup 130}Te and {sup 116}Cd. A Bayesian analysis is performed to estimate the signal strength of 0νββ-decay.
The contribution of light Majorana neutrinos to neutrinoless double beta decay and cosmology
Energy Technology Data Exchange (ETDEWEB)
Dell’Oro, S.; Marcocci, S. [INFN, Gran Sasso Science Institute,Viale F. Crispi 7, 67100 L’Aquila (Italy); Viel, M. [INAF, Osservatorio Astronomico di Trieste,Via G.B. Tiepolo 11, 34131 Trieste (Italy); INFN, Sezione di Trieste,Via Valerio 2, 34127 Trieste (Italy); Vissani, F. [INFN, Laboratori Nazionali del Gran Sasso,Via G. Acitelli 22, 67100 Assergi (AQ) (Italy); INFN, Gran Sasso Science Institute,Viale F. Crispi 7, 67100 L’Aquila (Italy)
2015-12-11
Cosmology is making impressive progress and it is producing stringent bounds on the sum of the neutrino masses Σ, a parameter of great importance for the current laboratory experiments. In this letter, we exploit the potential relevance of the analysis of Palanque-Delabrouille et al. to the neutrinoless double beta decay (0νββ) search. This analysis indicates small values for the lightest neutrino mass, since the authors find Σ<84 meV at 1σ C.L., and provides a 1σ preference for the normal hierarchy. The allowed values for the Majorana effective mass, probed by 0νββ, turn out to be <75 meV at 3σ C.L. and lower down to less than 20 meV at 1σ C.L. . If this indication is confirmed, the impact on the 0νββ experiments will be tremendous since the possibility of detecting a signal will be out of the reach of the next generation of experiments.
A neutrino mass-mixing sum rule from SO(10) and neutrinoless double beta decay
Energy Technology Data Exchange (ETDEWEB)
Buccella, F. [INFN, Sezione di Napoli,Complesso University Monte S. Angelo, I-80126 Napoli (Italy); Chianese, M. [INFN, Sezione di Napoli,Complesso University Monte S. Angelo, I-80126 Napoli (Italy); Dipartimento di Fisica Ettore Pancini, Università di Napoli Federico II,Complesso University Monte S. Angelo, I-80126 Napoli (Italy); Mangano, G. [INFN, Sezione di Napoli,Complesso University Monte S. Angelo, I-80126 Napoli (Italy); Miele, G.; Morisi, S.; Santorelli, P. [INFN, Sezione di Napoli,Complesso University Monte S. Angelo, I-80126 Napoli (Italy); Dipartimento di Fisica Ettore Pancini, Università di Napoli Federico II,Complesso University Monte S. Angelo, I-80126 Napoli (Italy)
2017-04-03
Minimal SO(10) grand unified models provide phenomenological predictions for neutrino mass patterns and mixing. These are the outcome of the interplay of several features, namely: i) the seesaw mechanism; ii) the presence of an intermediate scale where B-L gauge symmetry is broken and the right-handed neutrinos acquire a Majorana mass; iii) a symmetric Dirac neutrino mass matrix whose pattern is close to the up-type quark one. In this framework two natural characteristics emerge. Normal neutrino mass hierarchy is the only allowed, and there is an approximate relation involving both light-neutrino masses and mixing parameters. This differs from what occurring when horizontal flavour symmetries are invoked. In this case, in fact, neutrino mixing or mass relations have been separately obtained in literature. In this paper we discuss an example of such comprehensive mixing-mass relation in a specific realization of SO(10) and, in particular, analyse its impact on the expected neutrinoless double beta decay effective mass parameter 〈m{sub ee}〉, and on the neutrino mass scale. Remarkably a lower limit for the lightest neutrino mass is obtained (m{sub lightest}≳7.5×10{sup −4} eV, at 3 σ level).
Energy Technology Data Exchange (ETDEWEB)
Artusa, D.R. [University of South Carolina, Department of Physics and Astronomy, Columbia, SC (United States); INFN-Laboratori Nazionali del Gran Sasso, Assergi, L' Aquila (Italy); Avignone, F.T.; Chott, N.; Creswick, R.J.; Farach, H.A.; Rosenfeld, C.; Wilson, J. [University of South Carolina, Department of Physics and Astronomy, Columbia, SC (United States); Azzolini, O.; Camacho, A.; De Biasi, A.; Keppel, G.; Palmieri, V.; Pira, C.; Rampazzo, V. [INFN-Laboratori Nazionali di Legnaro, Legnaro, Padua (Italy); Balata, M.; Bucci, C.; Canonica, L.; Casali, N.; Di Vacri, M.L.; Goett, J.; Gorla, P.; Nisi, S.; Orlandi, D.; Pattavina, L.; Pirro, S.; Zarra, C. [INFN-Laboratori Nazionali del Gran Sasso, Assergi, L' Aquila (Italy); Banks, T.I. [INFN-Laboratori Nazionali del Gran Sasso, Assergi, L' Aquila (Italy); University of California, Department of Physics, Berkeley, CA (United States); Lawrence Berkeley National Laboratory, Nuclear Science Division, Berkeley, CA (United States); Bari, G.; Deninno, M.M.; Moggi, N. [INFN-Sezione di Bologna, Bologna (Italy); Beeman, J. [Lawrence Berkeley National Laboratory, Materials Science Division, Berkeley, CA (United States); Bellini, F.; Cardani, L.; Cosmelli, C.; Ferroni, F.; Piperno, G. [Sapienza Universita di Roma, Dipartimento di Fisica, Rome (Italy); INFN-Sezione di Roma, Rome (Italy); Bersani, A. [INFN-Sezione di Genova, Genoa (Italy); Biassoni, M.; Brofferio, C.; Capelli, S.; Carrettoni, M.; Chiesa, D.; Clemenza, M.; Faverzani, M.; Ferri, E.; Fiorini, E.; Giachero, A.; Gironi, L.; Gotti, C.; Maiano, C.; Maino, M.; Nucciotti, A.; Pavan, M.; Sala, E.; Sisti, M.; Terranova, F.; Zanotti, L. [Universita di Milano-Bicocca, Dipartimento di Fisica, Milan (Italy); INFN-Sezione di Milano Bicocca, Milan (Italy); Cai, X.Z.; Cao, X.G.; Fang, D.Q.; Li, Y.L.; Ma, Y.G.; Tian, W.D.; Wang, H.W. [Chinese Academy of Sciences, Shanghai Institute of Applied Physics, Shanghai (China); Carbone, L.; Cremonesi, O.; Datskov, V.; Pessina, G.; Previtali, E.; Rusconi, C. [INFN-Sezione di Milano Bicocca, Milan (Italy); Dafinei, I.; Morganti, S.; Orio, F.; Pettinacci, V.; Tomei, C.; Vignati, M. [INFN-Sezione di Roma, Rome (Italy); Dally, A.; Ejzak, L.; Wielgus, L. [University of Wisconsin, Department of Physics, Madison, WI (United States); Di Domizio, S.; Fernandes, G.; Pallavicini, M. [INFN-Sezione di Genova, Genoa (Italy); Universita di Genova, Dipartimento di Fisica, Genoa (Italy); Franceschi, M.A.; Ligi, C.; Napolitano, T. [INFN-Laboratori Nazionali di Frascati, Frascati, Rome (Italy); Freedman, S.J. [University of California, Department of Physics, Berkeley, CA (United States); Lawrence Berkeley National Laboratory, Nuclear Science Division, Berkeley, CA (United States); Fujikawa, B.K.; Han, K.; Mei, Y.; Smith, A.R. [Lawrence Berkeley National Laboratory, Nuclear Science Division, Berkeley, CA (United States); Giuliani, A.; Tenconi, M. [Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse, Orsay (France); Gutierrez, T.D. [California Polytechnic State University, Physics Department, San Luis Obispo, CA (United States); Haller, E.E. [Lawrence Berkeley National Laboratory, Materials Science Division, Berkeley, CA (United States); University of California, Department of Materials Science and Engineering, Berkeley, CA (United States); Heeger, K.M.; Maruyama, R.H. [Yale University, Department of Physics, New Haven, CT (United States); Hennings-Yeomans, R.; O' Donnell, T. [University of California, Department of Physics, Berkeley, CA (United States); Huang, H.Z.; Liu, X.; Trentalange, S.; Winslow, L.A.; Zhu, B.X. [University of California, Department of Physics and Astronomy, Los Angeles, CA (United States); Kadel, R. [Lawrence Berkeley National Laboratory, Physics Division, Berkeley, CA (United States); Kazkaz, K.; Pedretti, M.; Sangiorgio, S.; Scielzo, N.D. [Lawrence Livermore National Laboratory, Livermore, CA (United States); Kolomensky, Yu.G. [University of California, Department of Physics, Berkeley, CA (United States); Lawrence Berkeley National Laboratory, Physics Division, Berkeley, CA (United States); Martinez, M. [Universidad de Zaragoza, Laboratorio de Fisica Nuclear y Astroparticulas, Saragossa (Spain); Nones, C. [CEA/Saclay, Service de Physique des Particules, Gif-sur-Yvette (France); Norman, E.B.; Wang, B.S. [Lawrence Livermore National Laboratory, Livermore, CA (United States); University of California, Department of Nuclear Engineering, Berkeley, CA (United States); Ouellet, J.L. [University of California, Department of Physics, Berkeley, CA (United States); Lawrence Berkeley National Laboratory, Nuclear Science Division, Berkeley, CA (United States); Taffarello, L. [INFN-Sezione di Padova, Padua (Italy); Ventura, G. [Universita di Firenze, Dipartimento di Fisica, Florence (Italy); INFN-Sezione di Firenze, Florence (Italy); Wise, T. [University of Wisconsin, Department of Physics, Madison, WI (United States); Yale University, Department of Physics, New Haven, CT (United States); Woodcraft, A. [University of Edinburgh, SUPA, Institute for Astronomy, Edinburgh (United Kingdom); Zucchelli, S. [INFN-Sezione di Bologna, Bologna (Italy); Universita di Bologna, Dipartimento di Fisica, Bologna (Italy)
2014-10-15
Neutrinoless double beta decay (0νββ) is one of the most sensitive probes for physics beyond the Standard Model, providing unique information on the nature of neutrinos. In this paper we review the status and outlook for bolometric 0νββ decay searches. We summarize recent advances in background suppression demonstrated using bolometers with simultaneous readout of heat and light signals. We simulate several configurations of a future CUORE-like bolometer array which would utilize these improvements and present the sensitivity reach of a hypothetical next-generation bolometric 0νββ experiment. We demonstrate that a bolometric experiment with the isotope mass of about 1 ton is capable of reaching the sensitivity to the effective Majorana neutrino mass (vertical stroke m{sub ee} vertical stroke) of order 10-20 meV, thus completely exploring the so-called inverted neutrino mass hierarchy region. We highlight the main challenges and identify priorities for an R and D program addressing them. (orig.)
Weak decays and double beta decay. Annual progress report, January 1, 1982-December 31, 1982
International Nuclear Information System (INIS)
Nicholson, H.W.
1982-08-01
Work has continued in collaboration with experimenters from Yale, Brookhaven and Pittsburgh (Brookhaven experiment 702) to measure asymmetries in the decays of polarized Σ + 's into protons and neutral pions and of polarized Σ - 's into neutrons and negative pions. A short experiment was carried out in the Brookhaven AGS A2 test beam to measure the efficiency of a cylindrical shower counter essential for measuring the asymmetry parameter in the rare decay of polarized Σ + 's into protons and gammas. An electronic controller to stabilize the magnetic field of the superconducting, polarized target magnet was also designed and built at Mount Holyoke, and it functioned extremely well during a six week May to June run. Also, the design of an experiment to search for double beta decay in Molybdenum 100 is briefly described. A group consisting of five experimenters from LBL and two from Mount Holyoke hope to make a formal proposal in September to the LBL administration to begin work on this experiment late this year and during the next calendar year
Radiopurity assessment of the energy readout for the NEXT double beta decay experiment
Cebrián, S.; Pérez, J.; Bandac, I.; Labarga, L.; Álvarez, V.; Azevedo, C. D. R.; Benlloch-Rodríguez, J. M.; Borges, F. I. G. M.; Botas, A.; Cárcel, S.; Carrión, J. V.; Conde, C. A. N.; Díaz, J.; Diesburg, M.; Escada, J.; Esteve, R.; Felkai, R.; Fernandes, L. M. P.; Ferrario, P.; Ferreira, A. L.; Freitas, E. D. C.; Goldschmidt, A.; Gómez-Cadenas, J. J.; González-Díaz, D.; Gutiérrez, R. M.; Hauptman, J.; Henriques, C. A. O.; Hernandez, A. I.; Hernando Morata, J. A.; Herrero, V.; Jones, B. J. P.; Laing, A.; Lebrun, P.; Liubarsky, I.; López-March, N.; Losada, M.; Martín-Albo, J.; Martínez-Lema, G.; Martínez, A.; McDonald, A. D.; Monrabal, F.; Monteiro, C. M. B.; Mora, F. J.; Moutinho, L. M.; Muñoz Vidal, J.; Musti, M.; Nebot-Guinot, M.; Novella, P.; Nygren, D. R.; Palmeiro, B.; Para, A.; Querol, M.; Renner, J.; Ripoll, L.; Rodríguez, J.; Rogers, L.; Santos, F. P.; dos Santos, J. M. F.; Simón, A.; Sofka, C.; Sorel, M.; Stiegler, T.; Toledo, J. F.; Torrent, J.; Tsamalaidze, Z.; Veloso, J. F. C. A.; Villar, J. A.; Webb, R.; White, J. T.; Yahlali, N.
2017-08-01
The "Neutrino Experiment with a Xenon Time-Projection Chamber" (NEXT) experiment intends to investigate the neutrinoless double beta decay of 136Xe, and therefore requires a severe suppression of potential backgrounds. An extensive material screening and selection process was undertaken to quantify the radioactivity of the materials used in the experiment. Separate energy and tracking readout planes using different sensors allow us to combine the measurement of the topological signature of the event for background discrimination with the energy resolution optimization. The design of radiopure readout planes, in direct contact with the gas detector medium, was especially challenging since the required components typically have activities too large for experiments demanding ultra-low background conditions. After studying the tracking plane, here the radiopurity control of the energy plane is presented, mainly based on gamma-ray spectroscopy using ultra-low background germanium detectors at the Laboratorio Subterr&aposaneo de Canfranc (Spain). All the available units of the selected model of photomultiplier have been screened together with most of the components for the bases, enclosures and windows. According to these results for the activity of the relevant radioisotopes, the selected components of the energy plane would give a contribution to the overall background level in the region of interest of at most 2.4×10-4 counts keV-1 kg-1 y-1, satisfying the sensitivity requirements of the NEXT experiment.
Double beta decay - physics beyond the standard model now, and in future (Genius)
Energy Technology Data Exchange (ETDEWEB)
Klapdor-Kleingrothaus, H.V.
1998-08-01
Nuclear double beta decay provides an extraordinarily broad potential to search for beyond standard model physics, probing already now the TeV scale, on which new physics should manifest itself. These possibilities are reviewed here. First, the results of present generation experiments are presented. The most sensitive one of them - the Heidelberg-Moscow experiment in the Gran Sasso - probes the electron mass now in the sub eV region and will reach a limit of {proportional_to}0.1 eV in a few years. Basing to a large extent on the theoretical work of the Heidelberg double beta group in the last two years, results are obtained also for SUSY models (R-parity breaking, sneutrino mass), leptoquarks (leptoquark-Higgs coupling), compositeness, right-handed W boson mass and others. These results are comfortably competitive to corresponding results from high-energy accelerators like TEVATRON, HERA, etc. Second, future perspectives of {beta}{beta} research are discussed. A new Heidelberg experimental proposal (GENIUS) is presented which would allow to increase the sensitivity for Majorana neutrino masses from the present level of at best 0.1 eV down to 0.01 or even 0.001 eV. Its physical potential would be a breakthrough into the multi-TeV range for many beyond standard models. Its sensitivity for neutrino oscillation parameters would be larger than of all present terrestrial neutrino oscillation experiments and of those planned for the future. (orig.)
Radon and material radiopurity assessment for the NEXT double beta decay experiment
Energy Technology Data Exchange (ETDEWEB)
Cebrián, S.; Dafni, T.; González-Díaz, D.; Herrera, D. C.; Irastorza, I. G.; Luzón, G.; Ortiz de Solórzano, A.; Villar, J. A. [Laboratorio de Física Nuclear y Astropartículas, Universidad de Zaragoza, C/ Pedro Cerbuna 12, 50009 Zaragoza (Spain); Laboratorio Subterráneo de Canfranc, Paseo de los Ayerbe s/n, 22880 Canfranc Estación, Huesca (Spain); Pérez, J. [Instituto de Física Teórica, UAM/CSIC, Campus de Cantoblanco, 28049 Madrid (Spain); Bandac, I. [Laboratorio Subterráneo de Canfranc, Paseo de los Ayerbe s/n, 22880 Canfranc Estación, Huesca (Spain); Labarga, L. [Dpto. de Física Teórica, Universidad Autónoma de Madrid, Campus de Cantoblanco, 28049 Madrid (Spain); Álvarez, V.; Cárcel, S.; Cervera, A.; Díaz, J.; Ferrario, P.; Gómez-Cadenas, J. J.; Laing, A.; Liubarsky, I.; López-March, N. [Instituto de Física Corpuscular, CSIC & Universitat de València, C/ Catedrático José Beltrán, 2, 46980 Paterna, Valencia (Spain); and others
2015-08-17
The ”Neutrino Experiment with a Xenon TPC” (NEXT), intended to investigate the neutrinoless double beta decay using a high-pressure xenon gas TPC filled with Xe enriched in {sup 136}Xe at the Canfranc Underground Laboratory in Spain, requires ultra-low background conditions demanding an exhaustive control of material radiopurity and environmental radon levels. An extensive material screening process is underway for several years based mainly on gamma-ray spectroscopy using ultra-low background germanium detectors in Canfranc but also on mass spectrometry techniques like GDMS and ICPMS. Components from shielding, pressure vessel, electroluminescence and high voltage elements and energy and tracking readout planes have been analyzed, helping in the final design of the experiment and in the construction of the background model. The latest measurements carried out will be presented and the implication on NEXT of their results will be discussed. The commissioning of the NEW detector, as a first step towards NEXT, has started in Canfranc; in-situ measurements of airborne radon levels were taken there to optimize the system for radon mitigation and will be shown too.
Front-end electronics for accurate energy measurement of double beta decays
International Nuclear Information System (INIS)
Gil, A.; Díaz, J.; Gómez-Cadenas, J.J.; Herrero, V.; Rodriguez, J.; Serra, L.; Toledo, J.; Esteve, R.; Monzó, J.M.; Monrabal, F.; Yahlali, N.
2012-01-01
NEXT, a double beta decay experiment that will operate in Canfranc Underground Laboratory (Spain), aims at measuring the neutrinoless double-β decay of the 136Xe isotope using a TPC filled with enriched Xenon gas at high pressure operated in electroluminescence mode. One technological challenge of the experiment is to achieve resolution better than 1% in the energy measurement using a plane of UV sensitive photomultipliers readout with appropriate custom-made front-end electronics. The front-end is designed to be sensitive to the single photo-electron to detect the weak primary scintillation light produced in the chamber, and also to be able to cope with the electroluminescence signal (several hundred times higher and with a duration of microseconds). For efficient primary scintillation detection and precise energy measurement of the electroluminescent signals the front-end electronics features low noise and adequate amplification. The signal shaping provided allows the digitization of the signals at a frequency as low as 40 MHz.
Radon-induced surface contaminations in neutrinoless double beta decay and dark matter experiments
International Nuclear Information System (INIS)
Pattavina, L.
2011-01-01
In experiments looking for rare events, like neutrinoless double beta decay (DBD0ν) and dark matter search (DM), one of the main issues is to increase the experimental sensitivity through the material selection and production. The background contribution coming from the materials used for the detector realization has to be minimized. Moreover the net reduction of the background produced by the bulk part of the apparatus has raised concerns about the background contribution coming from the surfaces. Many procedures and techniques were developed during the last years in order to remove and to minimize the presence of possible contaminants on detector surfaces. To succeed in this strategy a big effort was put in defining all possible mechanisms that lead to surface contaminations, as well as specific cleaning procedures, which are able to reduce and control the surface radioactivity. The presence in air and gases of possible radioactive elements that can stick on the detector surfaces can lead to a recontamination process that will vanish all the applied cleaning procedures. Here is presented and analyzed the contribution to the background of rare events experiments like CUORE experiment (DBD0ν) and EDELWEISS experiment (DM) produced by an exposure of their detector components to a big activity of 222 Rn, radioactive daughter isotope from the 238 U chain. (author)
Atomic effects in tritium beta-decay. II. Muon to electron conversion in atoms
International Nuclear Information System (INIS)
Wampler, K.D.
1989-01-01
I. The final-state, atomic effects in the low energy end of the tritium beta decay spectrum are studied in detail. The author treats the instantaneous, two-electron repulsion in the final state, effectively to all orders in perturbation theory, by solving the eigenvalue problem with a discretized and truncated form of the Hamiltonian. He finds that these effects fail to explain the distortion in the spectrum observed by Simpson (Phys. Rev. Lett. 54, 649 (1985)). Simpson attributed this distortion to the admixture of a heavy mass antineutrino in the outgoing electron antineutrino state. In fact, the final-state Coulomb effects enhance the distortion. This calculation clears up some of the ambiguities of other theoretical analyses based on considerations of screening functions and perturbation theory. II. He presents a phenomenological study of separate lepton number violating muon to electron conversion in atoms. Previous work on this process has concentrated on elastic transitions where the nucleus characteristics have the gate on the substrate and the source-drain contacts on the top of the sample. The first use as an FET dielectric is reported of hydrogenated amorphous silicon-carbon (prepared from silane and propane mixture), photo-oxidised by UV lamp or laser. These FETs have similar characteristics to those with silicon nitride gate insulator but without the difficulties of preparing good insulator/semiconductor interfaces. Using the same materials attempts have been made to produce charge coupled devices
Double beta decay - physics beyond the standard model now, and in future (Genius)
International Nuclear Information System (INIS)
Klapdor-Kleingrothaus, H.V.
1998-01-01
Nuclear double beta decay provides an extraordinarily broad potential to search for beyond standard model physics, probing already now the TeV scale, on which new physics should manifest itself. These possibilities are reviewed here. First, the results of present generation experiments are presented. The most sensitive one of them - the Heidelberg-Moscow experiment in the Gran Sasso - probes the electron mass now in the sub eV region and will reach a limit of ∝0.1 eV in a few years. Basing to a large extent on the theoretical work of the Heidelberg double beta group in the last two years, results are obtained also for SUSY models (R-parity breaking, sneutrino mass), leptoquarks (leptoquark-Higgs coupling), compositeness, right-handed W boson mass and others. These results are comfortably competitive to corresponding results from high-energy accelerators like TEVATRON, HERA, etc. Second, future perspectives of ββ research are discussed. A new Heidelberg experimental proposal (GENIUS) is presented which would allow to increase the sensitivity for Majorana neutrino masses from the present level of at best 0.1 eV down to 0.01 or even 0.001 eV. Its physical potential would be a breakthrough into the multi-TeV range for many beyond standard models. Its sensitivity for neutrino oscillation parameters would be larger than of all present terrestrial neutrino oscillation experiments and of those planned for the future. (orig.)
The NEXT-100 experiment for neutrinoless double beta decay searches (Conceptual Design Report)
Álvarez, V; Batallé, M; Bayarri, J; Borges, F I G; Cárcel, S; Carmona, J M; Castel, J; Catalá, J M; Cebrián, S; Cervera-Villanueva, A; Chan, D; Conde, C A N; Dafni, T; Dias, T H V T; Díaz, J; Esteve, R; Evtoukhovitch, P; Fernandes, L M P; Ferrario, P; Ferrer-Ribas, E; Ferreira, A L; Freitas, E D C; Gil, A; Giomataris, I; Goldschmidt, A; Gómez, E; Gómez, H; Gómez-Cadenas, J J; Gónzález, K; Gutiérrez, R M; Hernando-Morata, J A; Herrera, D C; Herrero, V; Iguaz, F; Irastorza, I G; Kalinnikov, V; Kustov, A; Liubarsky, I; Lopes, J A M; Lorca, D; Losada, M; Luzón, G; Martín-Albo, J; Méndez, A; Miller, T; Moisenko, A; Mols, J P; Monrabal, F; Monteiro, C M B; Monzó, J M; Mora, F J; Muñoz-Vidal, J; da Luz, H Natal; Navarro, G; Nebot, M; Nygren, D; Oliveira, C A B; Palma, R; Pérez-Aparicio, J L; Renner, J; Ripoll, L; Rodríguez, A; Rodríguez, J; Santos, F P; Santos, J M F dos; Seguí, L; Serra, L; Sofka, C; Sorel, M; Spieler, H; Toledo, J F; Tomás, A; Tsamalaidze, Z; Vázquez, D; Velicheva, E; Veloso, J F C A; Villar, J A; Webb, R; Weber, T; White, J; Yahlali, N
2011-01-01
We propose an EASY (Electroluminescent ApparatuS of high Yield) and SOFT (Separated Optimized FuncTion) time-projection chamber for the NEXT experiment, that will search for neutrinoless double beta decay (bb0nu) in Xe-136. Our experiment must be competitive with the new generation of bb0nu searches already in operation or in construction. This requires a detector with very good energy resolution (<1%), very low background con- tamination (1E-4 counts/(keV \\bullet kg \\bullet y)) and large target mass. In addition, it needs to be operational as soon as possible. The design described here optimizes energy resolution thanks to the use of proportional electroluminescent amplification (EL); it is compact, as the Xe gas is under high pressure; and it allows the measurement of the topological signature of the event to further reduce the background contamination. The SOFT design uses different sensors for tracking and calorimetry. We propose the use of SiPMs (MPPCs) coated with a suitable wavelength shifter for th...
Civitarese, O.; Suhonen, J.; Zuber, K.
2015-07-01
The minimal extension of the standard model of electroweak interactions allows for massive neutrinos, a massive right-handed boson WR, and a left-right mixing angle ζ. While an estimate of the light (electron) neutrino can be extracted from the non-observation of the neutrinoless double beta decay, the limits on the mixing angle and the mass of the righthanded (RH) boson may be extracted from a combined analysis of the double beta decay measurements (GERDA, EXO-200 and KamLAND-Zen collaborations) and ATLAS data on the two-jets two-leptons signals following the excitation of a virtual RH boson mediated by a heavy-mass neutrino. In this work we shall compare results of both types of experiments, and show that the estimates are not in tension.
Measurement of the two neutrino double beta decay half-life of Zr-96 with the NEMO-3 detector
Energy Technology Data Exchange (ETDEWEB)
Argyriades, J. [LAL, Universite Paris-Sud 11, CNRS/IN2P3, F-91405 Orsay (France); Arnold, R. [IPHC, Universite de Strasbourg, CNRS/IN2P3, F-67037 Strasbourg (France); Augier, C. [LAL, Universite Paris-Sud 11, CNRS/IN2P3, F-91405 Orsay (France); Baker, J. [INL, Idaho National Laboratory, 83415 Idaho Falls (United States); Barabash, A.S. [ITEP, Institute of Theoretical and Experimental Physics, 117259 Moscow (Russian Federation); Basharina-Freshville, A. [University College London, WC1E 6BT London (United Kingdom); Bongrand, M. [LAL, Universite Paris-Sud 11, CNRS/IN2P3, F-91405 Orsay (France); Broudin-Bay, G. [Universite Bordeaux, CENBG, UMR 5797, F-33175 Gradignan (France); CNRS/IN2P3, Centre d' Etudes Nucleaires de Bordeaux Gradignan, UMR5797, F-33175 Gradignan (France); Brudanin, V. [JINR, Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Caffrey, A.J. [INL, Idaho National Laboratory, 83415 Idaho Falls (United States); Chapon, A. [LPC, ENSICAEN, Universite de Caen, CNRS/IN2P3, F-14032 Caen (France); Chauveau, E. [Universite Bordeaux, CENBG, UMR 5797, F-33175 Gradignan (France); CNRS/IN2P3, Centre d' Etudes Nucleaires de Bordeaux Gradignan, UMR5797, F-33175 Gradignan (France); Daraktchieva, Z. [University College London, WC1E 6BT London (United Kingdom); Durand, D. [LPC, ENSICAEN, Universite de Caen, CNRS/IN2P3, F-14032 Caen (France); Egorov, V. [JINR, Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Fatemi-Ghomi, N. [University of Manchester, M13 9PL Manchester (United Kingdom); Flack, R. [University College London, WC1E 6BT London (United Kingdom); Guillon, B. [LPC, ENSICAEN, Universite de Caen, CNRS/IN2P3, F-14032 Caen (France); Hubert, Ph. [Universite Bordeaux, CENBG, UMR 5797, F-33175 Gradignan (France); CNRS/IN2P3, Centre d' Etudes Nucleaires de Bordeaux Gradignan, UMR5797, F-33175 Gradignan (France); Jullian, S. [LAL, Universite Paris-Sud 11, CNRS/IN2P3, F-91405 Orsay (France)
2010-12-08
Using 9.4 g of {sup 96}Zr isotope and 1221 days of data from the NEMO-3 detector corresponding to 0.031 kg y, the obtained 2{nu}{beta}{beta} decay half-life measurement is T{sub 1/2}{sup 2{nu}=}[2.35{+-}0.14(stat){+-}0.16(syst)]x10{sup 19} yr. Different characteristics of the final state electrons have been studied, such as the energy sum, individual electron energy, and angular distribution. The 2{nu} nuclear matrix element is extracted using the measured 2{nu}{beta}{beta} half-life and is M{sup 2{nu}=}0.049{+-}0.002. Constraints on 0{nu}{beta}{beta} decay have also been set.
International Nuclear Information System (INIS)
Park, HyangKyu
2015-01-01
The AMoRE (Advanced Mo based Rare process Experiment) collaboration is going to use calcium molybdate crystals to search for neutrinoless double beta decay of 100 Mo isotope. In order to make the crystal, we use calcium carbonate and molybdenum oxide powders as raw materials. Therefore it is highly necessary to reduce potential sources for radioactive backgrounds such as U and Th in the powders. In this talk, we will present our studies for purification of calcium carbonate and molybdenum oxide powders
$\\beta$-asymmetry measurements in nuclear $\\beta$-decay as a probe for non-standard model physics
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.
Bound states in continuum: Quantum dots in a quantum well
Energy Technology Data Exchange (ETDEWEB)
Prodanović, Nikola, E-mail: elnpr@leeds.ac.uk [Institute of Microwaves and Photonics, School of Electronic and Electrical Engineering, University of Leeds, Woodhouse Lane, Leeds LS2 9JT (United Kingdom); Milanović, Vitomir [School of Electrical Engineering, University of Belgrade, Bulevar Kralja Aleksandra 73, 11000 Belgrade (Serbia); Ikonić, Zoran; Indjin, Dragan; Harrison, Paul [Institute of Microwaves and Photonics, School of Electronic and Electrical Engineering, University of Leeds, Woodhouse Lane, Leeds LS2 9JT (United Kingdom)
2013-11-01
We report on the existence of a bound state in the continuum (BIC) of quantum rods (QR). QRs are novel elongated InGaAs quantum dot nanostructures embedded in the shallower InGaAs quantum well. BIC appears as an excited confined dot state and energetically above the bottom of a well subband continuum. We prove that high height-to-diameter QR aspect ratio and the presence of a quantum well are indispensable conditions for accommodating the BIC. QRs are unique semiconductor nanostructures, exhibiting this mathematical curiosity predicted 83 years ago by Wigner and von Neumann.
Influence of low-energy scattering on loosely bound states
International Nuclear Information System (INIS)
Sparenberg, Jean-Marc; Capel, Pierre; Baye, Daniel
2010-01-01
Compact algebraic equations are derived that connect the binding energy and the asymptotic normalization constant (ANC) of a subthreshold bound state with the effective-range expansion of the corresponding partial wave. These relations are established for positively charged and neutral particles, using the analytic continuation of the scattering (S) matrix in the complex wave-number plane. Their accuracy is checked on simple local potential models for the 16 O+n, 16 O+p, and 12 C+α nuclear systems, with exotic nuclei and nuclear astrophysics applications in mind.
First observation of bound-state β-decay
International Nuclear Information System (INIS)
Jung, M.; Bosch, F.; Beckert, K.; Eickhoff, H.; Folger, H.; Franzke, B.; Kienle, P.; Klepper, O.; Koenig, W.; Kozhuharov, C.; Mann, R.; Moshammer, R.; Nolden, F.; Schaaf, U.; Soff, G.; Spaedtke, P.; Steck, M.; Stoehlker, T.; Suemmerer, K.
1992-06-01
Bound-state Β - decay was observed for the first time by storing bare 66 163 Dy 66+ ions in a heavy-ion storage ring. From the number of 67 163 Ho 66+ daughter ions, measured as a function of the storage time, a half-life of 47 4 +5 - d was derived. By comparing this result with reported half-lives for electron capture (EC) from the M 1 and M 2 shells of neutral 67 163 Ho, bounds for both the Q EC value of neutral 67 163 Ho and for the electron neutrino mass were set. (orig.)
Hunt for the 11P1 bound state of charmonium
International Nuclear Information System (INIS)
Porter, F.C.
1982-02-01
Using the Crystal Ball detector at SPEAR, we have looked for evidence of the isospin-violating decay psi' → π 01 P 1 , where 1 P 1 is the predicted spin-singlet p-wave bound state of charmonium. For a 1 P 1 state at the predicted mass (approx. 3520 MeV), we obtain the 95% confidence level limits: BR(psi' → π 01 P 1 ) 01 P 1 )BR( 1 P 1 → γn/sub c/ < 0.14%. These limits are compared with simple theoretical predictions
Bound states on the lattice with partially twisted boundary conditions
International Nuclear Information System (INIS)
Agadjanov, D.; Guo, F.-K.; Ríos, G.; Rusetsky, A.
2015-01-01
We propose a method to study the nature of exotic hadrons by determining the wave function renormalization constant Z from lattice simulations. It is shown that, instead of studying the volume-dependence of the spectrum, one may investigate the dependence of the spectrum on the twisting angle, imposing twisted boundary conditions on the fermion fields on the lattice. In certain cases, e.g., the case of the DK bound state which is addressed in detail, it is demonstrated that the partial twisting is equivalent to the full twisting up to exponentially small corrections.
Double-beta decay: Physics beyond the standard model now and in the future (GENIUS)
International Nuclear Information System (INIS)
Klapdor-Kleingrothaus, H.V.
1998-01-01
Nuclear double beta decay has an extraordinarily broad potential in searches for physics beyond the Standard Model, probing already now the TeV scale, at which new physics is expected to manifest itself. These possibilities are reviewed here. First, the result of present-generation experiments are discussed. The most sensitive one of these, the Heidelberg-Moscow experiment at the Gran Sasso underground laboratory, probes the electron mass now in the sub-eV region and will reach a limit of some 0.1 eV in a few years. On the basis of a large amount of theoretical work done by the Heidelberg Double Beta Group in the last two years, results are obtained also for SUSY models (R-parity breaking and neutrino mass), for leptoquarks (leptoquark-Higgs boson coupling), for compositeness, for right-handed W-boson mass, and for some other problems. These results are comfortably competitive with corresponding results from high-energy accelerators like Tevatron, HERA, etc. Future prospects for ββ research are discussed. A new Heidelberg experimental proposal (GENIUS) is presented, which would make it possible to increase the sensitivity for the Majorana neutrino masses from the present level of at best 0.1 eV down to 0.01 or even 0.001 eV. Its physical potential would be a breakthrough into the multi-TeV range for many models beyond standard. Its sensitivity for neutrino-oscillation parameters would be higher than that of all present terrestrial neutrino-oscillation experiments and that of those planned for the future. It would further, even at a first step, cover almost the full MSSM parameter space for prediction of neutralinos as cold dark matter, making the experimental competitive with LHC in searches for supersymmetry
Double Beta Decay - Physics Beyond the Standard Model Now, and in Future (GENIUS)
Klapdor-Kleingrothaus, H. V.
Nuclear double beta decay provides an extraordinarily broad potential to search for beyond Standard Model physics, probing already now the TeV scale, on which new physics should manifest itself. These possibilities are reviewed here. First, the results of present generation experiments are presented. The most sensitive one of them - the Heidelberg-Moscow experiment in the Gran Sasso - probes the electron mass now in the sub eV region and will reach a limit of ˜ 0.1 eV in a few years. Basing to a large extent on the theoretical work of the Heidelberg Double Beta Group in the last two years, results are obtained also for SUSY models (R-parity breaking, sneutrino mass), leptoquarks (leptoquark-Higgs coupling), com-positeness, right-handed W boson mass and others. These results are comfortably competitive to corresponding results from high-energy accelerators like TEVA-TRON, HERA, etc. Second, future perspectives of ʲʲ research are discussed. A new Heidelberg experimental proposal (GENIUS) is presented which would allow to increase the sensitivity for Majorana neutrino masses from the present level of at best 0.1 eV down to 0.01 or even 0.001 eV. Its physical potential would be a breakthrough into the multi-TeV range for many beyond standard models. Its sensitivity for neutrino oscillation parameters would be larger than of all present terrestrial neutrino oscillation experiments and of those planned for the future. It would further, already in a first step, cover almost the full MSSM parameter space for prediction of neutralinos as cold dark matter, making the experiment competitive to LHC in the search for supersymmetry.
Novel field cage design for the PandaX III double beta decay experiment
Chaiyabin, P.; Giboni, K. L.; Han, K.; Ji, X.; Juyal, P.; Kobdaj, C.; Liu, J.; Lomon, J.; Pasaja, N.; Poolcharuansin, P.; Rujirawat, S.; Songsiriritthigul, P.; Yan, Y.; Zhao, L.
2017-10-01
PandaX III is a High Pressure gaseous xenon Time Projection Chamber for Double Beta Decay detection. It will be installed deep underground in the JinPing Laboratory in Szechuan province, China. During its first phase the detector will operate with 200 kg of enriched 136Xe. The detector consists of a mesh cathode in the center of a cylindrical vessel and Micro-Bulk Micro-Megas at both ends to read out the drifting charges. The active volume is surrounded by an array of electrodes to shape the homogeneous drift field, the so called field cage. Gaseous xenon, however, is a poor dielectric. It would require in excess of 10 cm to safely stand off the HV between these electrodes and the grounded detector walls. Nearly a quarter of our available xenon would be wasted in this dead space. In a new design the electric field outside the field shaping is totally contained in a cylinder 1.6 m diameter and 2 m long. For manufacturing two 50 mm thick Acrylic plates are bend into half cylinders and bonded together. The outside surface of the cylinder is covered with a copper mesh as ground plane. The gap between field cage and detector vessel can be now reduced to 1 mm, and this gap is field free. The amount of wasted xenon is reduced by a factor 100. The field shaping electrodes and the resistive divider network are mounted on 5 mm thick Acrylic panels suspended on the inside of the field cage. This design is realized with low radioactivity materials.
Beta decay heat following U-235, U-238 and Pu-239 neutron fission
Li, Shengjie
1997-09-01
This is an experimental study of beta-particle decay heat from 235U, 239Pu and 238U aggregate fission products over delay times 0.4-40,000 seconds. The experimental results below 2s for 235U and 239Pu, and below 20s for 238U, are the first such results reported. The experiments were conducted at the UMASS Lowell 5.5-MV Van de Graaff accelerator and 1-MW swimming-pool research reactor. Thermalized neutrons from the 7Li(p,n)7Be reaction induced fission in 238U and 239Pu, and fast neutrons produced in the reactor initiated fission in 238U. A helium-jet/tape-transport system rapidly transferred fission fragments from a fission chamber to a low background counting area. Delay times after fission were selected by varying the tape speed or the position of the spray point relative to the beta spectrometer that employed a thin-scintillator-disk gating technique to separate beta-particles from accompanying gamma-rays. Beta and gamma sources were both used in energy calibration. Based on low-energy(energies 0-10 MeV. Measured beta spectra were unfolded for their energy distributions by the program FERD, and then compared to other measurements and summation calculations based on ENDF/B-VI fission-product data performed on the LANL Cray computer. Measurements of the beta activity as a function of decay time furnished a relative normalization. Results for the beta decay heat are presented and compared with other experimental data and the summation calculations.
A narrow quasi-bound state of the DNN system
International Nuclear Information System (INIS)
Doté, A.; Bayar, M.; Xiao, C.W.; Hyodo, T.; Oka, M.; Oset, E.
2013-01-01
We have investigated a charmed system of DNN (composed of two nucleons and a D meson) by a complementary study with a variational calculation and a Faddeev calculation with fixed-center approximation (Faddeev-FCA). In the present study, we employ a DN potential based on a vector–meson exchange picture in which a resonant Λ c (2595) is dynamically generated as a DN quasi-bound state, similarly to the Λ(1405) as a K ¯ N one in the strange sector. As a result of the study of variational calculation with an effective DN potential and three kinds of NN potentials, the DNN(J π =0 − ,I=1/2) is found to be a narrow quasi-bound state below Λ c (2595)N threshold: total binding energy ∼225 MeV and mesonic decay width ∼25 MeV. On the other hand, the J π =1 − state is considered to be a scattering state of Λ c (2595) and a nucleon. These results are essentially supported by the Faddeev-FCA calculation. By the analysis of the variational wave function, we have found a unique structure in the DNN(J π =0 − ,I=1/2) such that the D meson stays around the center of the total system due to the heaviness of the D meson
What can Andreev bound states tell us about superconductors?
Millo, Oded; Koren, Gad
2018-08-06
Zero-energy Andreev bound states, which manifest themselves in the tunnelling spectra as zero-bias conductance peaks (ZBCPs), are abundant at interfaces between superconductors and other materials and on the nodal surface of high-temperature superconductors. In this review, we focus on the information such excitations can provide on the properties of superconductor systems. First, a general introduction to the physics of Andreev bound states in superconductor/normal metal interfaces is given with a particular emphasis on why they appear at zero energy in d -wave superconductors. Then, specific spectroscopic tunnelling studies of thin films, bilayers and junctions are described, focusing on the corresponding ZBCP features. Scanning tunnelling spectroscopy (STS) studies show that the ZBCPs on the c -axis YBa 2 Cu 3 O 7- δ (YBCO) films are correlated with the surface morphology and appear only in proximity to (110) facets. STS on c -axis La 1.88 Sr 0.12 CuO 4 (LSCO) films exhibiting the 1/8 anomaly shows spatially modulated peaks near zero bias associated with the anti-phase ordering of the d -wave order parameter predicted at this doping level. ZBCPs were also found in micrometre-size edge junctions of YBCO/SrRuO 3 /YBCO, where SrRuO 3 is ferromagnetic. Here, the results are consistent with a crossed Andreev reflection effect (CARE) at the narrow domain walls of the SrRuO 3 ZBCPs measured in STS studies of manganite/cuprate bilayers could not be attributed to CARE because the manganite's domain wall is much larger than the coherence length in YBCO, and instead are attributed to proximity-induced triplet-pairing superconductivity with non-conventional symmetry. And finally, ZBCPs found in junctions of non-intentionally doped topological insulator films of Bi 2 Se 3 and the s -wave superconductor NbN are attributed to proximity-induced p x + ip y triplet order parameter in the topological material.This article is part of the theme issue 'Andreev bound states'.
Meson exchange currents in nuclei; the triton beta decay as an example
International Nuclear Information System (INIS)
Jaus, W.
1976-01-01
The method used to reduce the four-dimensional Bethe-Salpeter equation to the three-dimensional Schroedinger equation, thus defining a potential in terms of the field theoretic interaction, can be generalized to define a consistent exchange by considering the relativistic interaction of a current with a bound state of nucleons. This covariant approach allows a unified treatment of exchange current effects, renormalization of the nuclear wave function due to meson exchange, relativistic corrections and negative energy contributions to the wave function and it is discussed in detail how these effects influence the Gamow-Teller matrix element for the decay 3 H→ 3 He + e + antiγ. One and two-meson exchange processes are calculated including nucleon resonances in intermediate states, and good agreement of theoretical and experimental predictions for the GT matrix element is found. (Auth.)
GERDA results and the future perspectives for the neutrinoless double beta decay search using 76Ge
Agostini, M.; Bakalyarov, A. M.; Balata, M.; Barabanov, I.; Baudis, L.; Bauer, C.; Bellotti, E.; Belogurov, S.; Bettini, A.; Bezrukov, L.; Biernat, J.; Bode, T.; Borowicz, D.; Brudanin, V.; Brugnera, R.; Caldwell, A.; Cattadori, C.; Chernogorov, A.; Comellato, T.; D’Andrea, V.; Demidova, E. V.; di Marco, N.; Domula, A.; Doroshkevich, E.; Egorov, V.; Gangapshev, A.; Garfagnini, A.; Giordano, M.; Grabmayr, P.; Gurentsov, V.; Gusev, K.; Hakenmüller, J.; Heisel, M.; Hemmer, S.; Hiller, R.; Hofmann, W.; Hult, M.; Inzhechik, L. V.; Janicskó Csáthy, J.; Jochum, J.; Junker, M.; Kazalov, V.; Kermaidic, Y.; Kihm, T.; Kirpichnikov, I. V.; Kirsch, A.; Klimenko, A.; Kneißl, R.; Knöpfle, K. T.; Kochetov, O.; Kornoukhov, V. N.; Kuzminov, V. V.; Laubenstein, M.; Lazzaro, A.; Lindner, M.; Lippi, I.; Lubashevskiy, A.; Lubsandorzhiev, B.; Lutter, G.; Macolino, C.; Majorovits, B.; Maneschg, W.; Miloradovic, M.; Mingazheva, R.; Misiaszek, M.; Moseev, P.; Nemchenok, I.; Panas, K.; Pandola, L.; Pelczar, K.; Pertoldi, L.; Pullia, A.; Ransom, C.; Riboldi, S.; Rumyantseva, N.; Sada, C.; Salamida, F.; Schneider, B.; Schönert, S.; Schreiner, J.; Schütz, A.-K.; Schulz, O.; Schwingenheuer, B.; Selivanenko, O.; Shevchik, E.; Shirchenko, M.; Simgen, H.; Smolnikov, A.; Stanco, L.; Vanhoefer, L.; Vasenko, A. A.; Veresnikova, A.; von Sturm, K.; Wagner, V.; Wegmann, A.; Wester, T.; Wiesinger, C.; Wojcik, M.; Yanovich, E.; Zhitnikov, I.; Zhukov, S. V.; Zinatulina, D.; Zschocke, A.; Zsigmond, A. J.; Zuber, K.; Zuzel, G.
2018-03-01
The GERmanium Detector Array (GERDA) is a low background experiment at the Laboratori Nazionali del Gran Sasso (LNGS) of INFN designed to search for the rare neutrinoless double beta decay (0νββ) of 76Ge. In the first phase (Phase I) of the experiment, high purity germanium diodes were operated in a “bare” mode and immersed in liquid argon. The overall background level of 10‑2cts/(keV ṡkg ṡyr) was a factor of ten better than those of its predecessors. No signal was found and a lower limit was set on the half-life for the 0νββ decay of 76Ge T1/20ν > 2.1 × 1025 yr (90% CL), while the corresponding median sensitivity was 2.4 × 1025 yr (90% CL). A second phase (Phase II) started at the end of 2015 after a major upgrade. Thanks to the increased detector mass and performance of the enriched germanium diodes and due to the introduction of liquid argon instrumentation techniques, it was possible to reduce the background down to 10‑3cts/(keV ṡkg ṡyr). After analyzing 23.2 kgṡyr of these new data no signal was seen. Combining these with the data from Phase I a stronger half-life limit of the 76Ge 0νββ decay was obtained: T1/20ν > 8.0 × 1025 yr (90% CL), reaching a sensitivity of 5.8 × 1025 yr (90% CL). Phase II will continue for the collection of an exposure of 100 kg ṡyr. If no signal is found by then the GERDA sensitivity will have reached 1.4 × 1026 yr for setting a 90% CL. limit. After the end of GERDA Phase II, the flagship experiment for the search of 0νββ decay of 76Ge will be LEGEND. LEGEND experiment is foreseen to deploy up to 1-ton of 76Ge. After ten years of data taking, it will reach a sensitivity beyond 1028 yr, and hence fully cover the inverted hierarchy region.
Impurity bound states in mesoscopic topological superconducting loops
Jin, Yan-Yan; Zha, Guo-Qiao; Zhou, Shi-Ping
2018-06-01
We study numerically the effect induced by magnetic impurities in topological s-wave superconducting loops with spin-orbit interaction based on spin-generalized Bogoliubov-de Gennes equations. In the case of a single magnetic impurity, it is found that the midgap bound states can cross the Fermi level at an appropriate impurity strength and the circulating spin current jumps at the crossing point. The evolution of the zero-energy mode can be effectively tuned by the located site of a single magnetic impurity. For the effect of many magnetic impurities, two independent midway or edge impurities cannot lead to the overlap of zero modes. The multiple zero-energy modes can be effectively realized by embedding a single Josephson junction with impurity scattering into the system, and the spin current displays oscillatory feature with increasing the layer thickness.
Static and dynamic properties of QCD bound states
International Nuclear Information System (INIS)
Kubrak, Stanislav
2015-01-01
The QCD phenomenology can be faced with the framework of the coupled quark DSE, meson BSE and baryon Faddeev equation, providing non-perturbative, continuum and Poincare invariant scientific approach. The research performed throughout this thesis is twofold. From one perspective we focus on the investigation of mass spectra for mesons with total spin quantum number J=3 and arising Regge-trajectory for natural parity states J PC =1 -- ,2 ++ ,3 -- within rainbow-ladder single gluon exchange model. The other findings are concerning the impact of the pion cloud effect on J>2 meson states, baryon masses, namely on Nucleon and Delta three-body bound states and meson dynamical properties like the pion form factor.
Bound states for non-symmetric evolution Schroedinger potentials
Energy Technology Data Exchange (ETDEWEB)
Corona, Gulmaro Corona [Area de Analisis Matematico y sus Aplicaciones, Universidad Autonoma Metropolitana-Azcapotalco, Atzcapotzalco, DF (Mexico)). E-mail: ccg@correo.azc.uam.mx
2001-09-14
We consider the spectral problem associated with the evolution Schroedinger equation, (D{sup 2}+ k{sup 2}){phi}=u{phi}, where u is a matrix-square-valued function, with entries in the Schwartz class defined on the real line. The solution {phi}, called the wavefunction, consists of a function of one real variable, matrix-square-valued with entries in the Schwartz class. This problem has been dealt for symmetric potentials u. We found for the present case that the bound states are localized similarly to the scalar and symmetric cases, but by the zeroes of an analytic matrix-valued function. If we add an extra condition to the potential u, we can determine these states by an analytic scalar function. We do this by generalizing the scalar and symmetric cases but without using the fact that the Wronskian of a pair of wavefunction is constant. (author)
Pair condensation and bound states in fermionic systems
International Nuclear Information System (INIS)
Sedrakian, Armen; Clark, John W.
2006-01-01
We study the finite temperature-density phase diagram of an attractive fermionic system that supports two-body (dimer) and three-body (trimer) bound states in free space. Using interactions characteristic for nuclear systems, we obtain the critical temperature T c2 for the superfluid phase transition and the limiting temperature T c3 for the extinction of trimers. The phase diagram features a Cooper-pair condensate in the high-density, low-temperature domain which, with decreasing density, crosses over to a Bose condensate of strongly bound dimers. The high-temperature, low-density domain is populated by trimers whose binding energy decreases toward the density-temperature domain occupied by the superfluid and vanishes at a critical temperature T c3 >T c2
Meson bound states and inclusive hardon scattering in quantum chromodynamics
International Nuclear Information System (INIS)
Beavis, D.R.
1980-01-01
In the first part we study the charmonium and UPSILON systems with a simple Coulomb plus linear potential. The parameters of the potential are determined by the charmonium states other than 1 S 0 states. We successfully predict that the states X(2830) and x(3450) are not the 1 S 0 partners of J/psi and psi'. The same effective potential also gives a good description of the UPSILON system. The Lorentz nature of the confinement potential is determined to be an equal mixture of vector and scalar. In the second part we extend a method for obtaining bound states and wavefunctions for relativistic confined systems. The important aspect of this treatment is the input of the asymptotic expansion of the two-point functions. We test the bound state approximation for a system defined by an equivalent potential V(r) = lambda 2 tanh 2 (g 2 r/lambda). Excellent results are obtained, even though a threshold is present. Finally, in the third section, we analyze the 100 GeV/c π - p→π 0 X data of Barnes et al. for moderate t, 1.5 less than or equal to -t less than or equal to 4.0 (GeV/c) 2 with the constituent scattering models. We obtain very good agreement in normalization and the x and t behavior of dsigma/dtdx using the FF1 model. The analysis of π - p→etaX gives additional support to this interpretation. The predictions of perturbative QCD and FF1 for π - p→π 0 X are given
Rajput, M. U.; Ali, N.; Hussain, S.; Mujahid, S. A.; MacMahon, D.
2012-04-01
The radionuclide 125Sb is a long-lived fission product, which decays to 125Te by negative beta emission with a half-life of 1008 day. The beta decay is followed by the emission of several gamma radiations, ranging from low to medium energy, that can suitably be used for high-resolution detector calibrations, decay heat calculations and in many other applications. In this work, the beta decay of 125Sb has been studied in detail. The complete published experimental data of relative gamma ray intensities in the beta decay of the radionuclide 125Sb has been compiled. The consistency analysis was performed and discrepancies found at several gamma ray energies. Evaluation of the discrepant data was carried out using Normalized Residual and RAJEVAL methods. The decay scheme balance was carried out using beta branching ratios, internal conversion coefficients, populating and depopulating gamma transitions to 125Te levels. The work has resulted in the consistent conversion factor equal to 29.59(13) %, and determined a new evaluated set of the absolute gamma ray emission probabilities. The work has also shown 22.99% of the delayed intensity fraction as outgoing from the 58 d isomeric 144 keV energy level and 77.01% of the prompt intensity fraction reaching to the ground state from the other excited states. The results are discussed and compared with previous evaluations. The present work includes additional experimental data sets which were not included in the previous evaluations. A new set of recommended relative and absolute gamma ray emission probabilities is presented.
Energy Technology Data Exchange (ETDEWEB)
Armengaud, E.; Gros, M.; Herve, S.; Magnier, P.; Navick, X.F.; Nones, C.; Paul, B.; Penichot, Y.; Zolotarova, A.S. [Universite Paris-Saclay, IRFU, CEA, Gif-sur-Yvette (France); Augier, C.; Billard, J.; Cazes, A.; Charlieux, F.; Jesus, M. de; Gascon, J.; Juillard, A.; Queguiner, E.; Sanglard, V.; Vagneron, L. [Univ Lyon, Universite Lyon 1, CNRS/IN2P3, IPN-Lyon, Villeurbanne (France); Barabash, A.S.; Konovalov, S.I.; Umatov, V.I. [National Research Centre Kurchatov Institute, Institute of Theoretical and Experimental Physics, Moscow (Russian Federation); Beeman, J.W. [Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Bekker, T.B. [V.S. Sobolev Institute of Geology and Mineralogy of the Siberian Branch of the RAS, Novosibirsk (Russian Federation); Bellini, F.; Ferroni, F. [Sapienza Universita di Roma, Dipartimento di Fisica, Rome (Italy); INFN, Sezione di Roma, Rome (Italy); Benoit, A.; Camus, P. [CNRS-Neel, Grenoble (France); Berge, L.; Chapellier, M.; Dumoulin, L.; Humbert, V.; Le Sueur, H.; Marcillac, P. de; Marnieros, S.; Marrache-Kikuchi, C.; Novati, V.; Olivieri, E.; Plantevin, O. [CSNSM, Univ. Paris-Sud, CNRS/IN2P3, Universite Paris-Saclay, Orsay (France); Bergmann, T.; Kleifges, M.; Tcherniakhovski, D.; Weber, M. [Karlsruhe Institute of Technology, Institut fuer Prozessdatenverarbeitung und Elektronik, Karlsruhe (Germany); Boiko, R.S.; Danevich, F.A.; Kobychev, V.V.; Nikolaichuk, M.O.; Tretyak, V.I. [Institute for Nuclear Research, Kyiv (Ukraine); Broniatowski, A. [CSNSM, Univ. Paris-Sud, CNRS/IN2P3, Universite Paris-Saclay, Orsay (France); Karlsruhe Institute of Technology, Institut fuer Experimentelle Teilchenphysik, Karlsruhe (Germany); Brudanin, V.; Rozov, S.; Yakushev, E. [JINR, Laboratory of Nuclear Problems, Dubna, Moscow Region (Russian Federation); Capelli, S.; Gironi, L.; Pavan, M.; Pessina, G. [Universita di Milano Bicocca, Dipartimento di Fisica, Milan (Italy); INFN, Sezione di Milano Bicocca, Milan (Italy); Cardani, L.; Casali, N.; Dafinei, I.; Tomei, C.; Vignati, M. [INFN, Sezione di Roma, Rome (Italy); Chernyak, D.M. [Institute for Nuclear Research, Kyiv (Ukraine); The University of Tokyo, Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo Institutes for Advanced Study, Kashiwa, Chiba (Japan); Combarieu, M. de; Pari, P. [Universite Paris-Saclay, IRAMIS, CEA, Gif-sur-Yvette (France); Coron, N.; Redon, T. [Universite Paris-Sud, IAS, CNRS, Orsay (France); Devoyon, L.; Koskas, F.; Strazzer, O. [Universite Paris-Saclay, Orphee, CEA, Gif-sur-Yvette (France); Di Domizio, S. [Universita di Genova, Dipartimento di Fisica, Genoa (Italy); INFN Sezione di Genova, Genoa (Italy); Eitel, K.; Siebenborn, B. [Karlsruhe Institute of Technology, Institut fuer Kernphysik, Karlsruhe (Germany); Enss, C.; Fleischmann, A.; Gastaldo, L. [Heidelberg University, Kirchhoff Institute for Physics, Heidelberg (Germany); Foerster, N.; Kozlov, V. [Karlsruhe Institute of Technology, Institut fuer Experimentelle Teilchenphysik, Karlsruhe (Germany); Giuliani, A. [CSNSM, Univ. Paris-Sud, CNRS/IN2P3, Universite Paris-Saclay, Orsay (France); Universita dell' Insubria, DISAT, Como (Italy); Grigorieva, V.D.; Ivannikova, N.V.; Ivanov, I.M.; Makarov, E.P.; Shlegel, V.N.; Vasiliev, Ya.V. [Nikolaev Institute of Inorganic Chemistry, Novosibirsk (Russian Federation); Hehn, L. [Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Karlsruhe Institute of Technology, Institut fuer Kernphysik, Karlsruhe (Germany); Jin, Y. [Laboratoire de Photonique et de Nanostructures, CNRS, Marcoussis (France); Kraus, H. [University of Oxford, Department of Physics, Oxford (United Kingdom); Kudryavtsev, V.A. [University of Sheffield, Department of Physics and Astronomy, Sheffield (United Kingdom); Laubenstein, M.; Nagorny, S.; Pattavina, L.; Pirro, S. [INFN, Laboratori Nazionali del Gran Sasso, Assergi, AQ (Italy); Loidl, M.; Rodrigues, M. [CEA-Saclay, CEA, LIST, Laboratoire National Henri Becquerel (LNE-LNHB), Gif-sur-Yvette Cedex (France); Mancuso, M. [CSNSM, Univ. Paris-Sud, CNRS/IN2P3, Universite Paris-Saclay, Orsay (France); Universita dell' Insubria, DISAT, Como (Italy); Max-Planck-Institut fuer Physik, Munich (Germany); Pagnanini, L.; Schaeffner, K. [INFN, Laboratori Nazionali del Gran Sasso, Assergi, AQ (Italy); INFN, Gran Sasso Science Institute, L' Aquila (Italy); Piperno, G. [INFN, Laboratori Nazionali di Frascati, Rome (Italy); Poda, D.V. [CSNSM, Univ. Paris-Sud, CNRS/IN2P3, Universite Paris-Saclay, Orsay (France); Institute for Nuclear Research, Kyiv (Ukraine); Rusconi, C. [INFN, Laboratori Nazionali del Gran Sasso, Assergi, AQ (Italy); University of South Carolina, Department of Physics and Astronomy, Columbia, SC (United States); Scorza, S. [Karlsruhe Institute of Technology, Institut fuer Experimentelle Teilchenphysik, Karlsruhe (Germany); SNOLAB, Lively, ON (Canada); Velazquez, M. [Universite de Bordeaux, ICMCB, CNRS, Pessac (France)
2017-11-15
This paper reports on the development of a technology involving {sup 100}Mo-enriched scintillating bolometers, compatible with the goals of CUPID, a proposed next-generation bolometric experiment to search for neutrinoless double-beta decay. Large mass (∝ 1 kg), high optical quality, radiopure {sup 100}Mo-containing zinc and lithium molybdate crystals have been produced and used to develop high performance single detector modules based on 0.2-0.4 kg scintillating bolometers. In particular, the energy resolution of the lithium molybdate detectors near the Q-value of the double-beta transition of {sup 100}Mo (3034 keV) is 4-6 keV FWHM. The rejection of the α-induced dominant background above 2.6 MeV is better than 8σ. Less than 10 μBq/kg activity of {sup 232}Th({sup 228}Th) and {sup 226}Ra in the crystals is ensured by boule recrystallization. The potential of {sup 100}Mo-enriched scintillating bolometers to perform high sensitivity double-beta decay searches has been demonstrated with only 10 kg x d exposure: the two neutrino double-beta decay half-life of {sup 100}Mo has been measured with the up-to-date highest accuracy as T{sub 1/2} = [6.90 ± 0.15(stat.) ± 0.37(syst.)] x 10{sup 18} years. Both crystallization and detector technologies favor lithium molybdate, which has been selected for the ongoing construction of the CUPID-0/Mo demonstrator, containing several kg of {sup 100}Mo. (orig.)
International Nuclear Information System (INIS)
Rajput, M.U.; Ali, N.; Hussain, S.; Mujahid, S.A.; MacMahon, D.
2012-01-01
The radionuclide 125 Sb is a long-lived fission product, which decays to 125 Te by negative beta emission with a half-life of 1008 day. The beta decay is followed by the emission of several gamma radiations, ranging from low to medium energy, that can suitably be used for high-resolution detector calibrations, decay heat calculations and in many other applications. In this work, the beta decay of 125 Sb has been studied in detail. The complete published experimental data of relative gamma ray intensities in the beta decay of the radionuclide 125 Sb has been compiled. The consistency analysis was performed and discrepancies found at several gamma ray energies. Evaluation of the discrepant data was carried out using Normalized Residual and RAJEVAL methods. The decay scheme balance was carried out using beta branching ratios, internal conversion coefficients, populating and depopulating gamma transitions to 125 Te levels. The work has resulted in the consistent conversion factor equal to 29.59(13) %, and determined a new evaluated set of the absolute gamma ray emission probabilities. The work has also shown 22.99% of the delayed intensity fraction as outgoing from the 58 d isomeric 144 keV energy level and 77.01% of the prompt intensity fraction reaching to the ground state from the other excited states. The results are discussed and compared with previous evaluations. The present work includes additional experimental data sets which were not included in the previous evaluations. A new set of recommended relative and absolute gamma ray emission probabilities is presented.
Search for the neutrinoless double beta decay (0νββ) of {sup 76}Ge: GERDA Phase II commissioning
Energy Technology Data Exchange (ETDEWEB)
Bode, Tobias [Physik-Department E15, Technische Universitaet Muenchen (Germany); Collaboration: GERDA-Collaboration
2015-07-01
After successful completion of Phase I the Gerda (Germanium Detector Array) experiment underwent a major upgrade of the experimental apparatus. These upgrades include additional 20 kg of custom-made detectors with improved background rejection capabilities, accompanied by improved front-end electronics and an active liquid argon scintillation light veto. A sensitivity on the neutrinoless double beta decay half-life (T{sub 1/2}{sup 0ν}) of 10{sup 26} yr should be reached after a few years of data taking (Phase II). First results of Phase II commissioning and latest results from Phase I analyses are presented in this talk.
Experimental proof of quantum non-separability based on the transition of the atom in beta-decay
International Nuclear Information System (INIS)
Vatai, E.
1988-01-01
The basic non-local character of the quantum processes is a continuously discussed and doubted problem of quantum theory. Recent experimental proofs of the Bell inequalities are questioned in the literature, using local theories of hidden variables. Present paper shows a simple and direct proof of non-locality of quantum processes, analyzing the case of the beta decay. The hypothetical energy transfer between shell electrons and beta electron-neutrino system is proved to be superluminal but necessary for the energy balance of the process. This argumentation proves the nonseparability and nonlocality of quantum processes. (D.G.) 8 refs
A zero-to-few-hundred eV proton beam for calibrations of neutron beta decay experiments
Naab, F; Zech, W; García, A; Mumm, P
2002-01-01
We have constructed a system using a duoplasmatron source to produce a beam of low-energy (0 - few hundred eV) protons with the principal goal of testing and calibrating detectors used to detect protons from neutron beta decay. The system is stable and produces beams by simply turning on the associated power supplies without the need of careful tuning. As an example we show data from calibration of a surface barrier detector in the emiT apparatus. Protons from the system were scattered from an Al target and used to calibrate detectors in the emiT apparatus.
Two neutrino double-beta decay of 100Mo to the first excited 0+ state in 100Ru
International Nuclear Information System (INIS)
Barabash, A.S.; Avignone, F.T. III; Guerard, C.K.; Umatov, V.I.
1992-06-01
Double-beta decay from the ground state of 100 Mo to the O + excited state at 1,130.29 keV in 100 Ru has been observed. A sample of 956q of Mo metal powder isotopically enriched to 98.468% of 100 Mo was counted in a Marinelli geometry with a well shielded, ultralow-background germanium detector. The cascade gamma-rays at 539.53 and 590.76 keV were observed. The resulting decay half-life is 1.1 -0.2 +0.3 x 10 21 y at 68% CL
International Nuclear Information System (INIS)
Margaritisz, Tanaszisz
1984-01-01
The Glashow-Weinberg-Salam theory of unified electromagnetic and weak interactions, believed to be the correct quantum theory of these interactions, possesses the great advantage of being renormable. Thus the perturbation theory is applicable to calculate the radiative corrections of the tree-graph results. The present paper describes the detailed calculation of one-loop corrections to beta decay of hyperons. After defining the theory and fixing the gauge and renormalization conventions, the equations of weak and electromagnetic one-loop corrections are derived. Numerical evaluation of the equations was helped by algebraic and integrator computer codes. The results are directly comparable to experimental data. (D.Gy.)
Energy Technology Data Exchange (ETDEWEB)
Kopeikin, V. I., E-mail: kopeikin46@yandex.ru; Skorokhvatov, M. D., E-mail: skorokhvatov-md@nrcki.ru [National Research Center Kurchatov Institute (Russian Federation)
2017-03-15
The evolution of the reactor-antineutrino spectrum and the evolution of the spectrum of positrons from the inverse-beta-decay reaction in the course of reactor operation and after reactor shutdown are considered. The present-day status in determining the initial reactor-antineutrino spectrum on the basis of spectra of beta particles from mixtures of products originating from uranium and plutonium fission is described. A local rise of the experimental spectrum of reactor antineutrinos with respect to the expected spectrum is studied.
Zimmer, O; Grinten, M G D; Heil, W; Glück, F
2000-01-01
The combination of the coefficient a of the antineutrino/electron angular correlation with the beta asymmetry of the neutron provides a sensitive test for scalar and tensor contributions to the electroweak Lagrangian, as well as for right-handed currents. A method is given for measuring a with high sensitivity from the proton recoil spectrum. The method is based on a magnetic spectrometer with electrostatic retardation potentials such as used for searches of the neutrino mass in tritium beta decay. The spectrometer can also be used for similar studies using radioactive nuclei.
Large impedances and Majorana bound states in superconducting circuits
International Nuclear Information System (INIS)
Ulrich, Jascha
2017-01-01
Superconducting circuits offer the opportunity to study quantum mechanics on mesoscopic scales unimpeded by dissipation. This fact and the nonlinearity of the Josephson inductance make it possible to use superconducting circuits as artificial atoms whose long-lived states can be selectively addressed and studied. A pronounced nonlinearity of the energy spectrum, however, requires quantum fluctuations of the flux across the Josephson junction which are large on the scale of the superconducting flux quantum Φ Q =h/2e. This implies charge fluctuations below the single Cooper-pair limit via flux-charge duality. The localization of charge leads to a strong susceptibility to interactions with charges in the environment which has motivated the search for schemes to decouple charges from their environment. This thesis is concerned with theoretical challenges arising from two complementary approaches to this problem: the realization of large impedances and the fractionalization of electrons by means of Majorana bound states. In recent years, the decoupling of charges from the environment through reactive large impedances, so-called ''superinductances'' L, has attracted much interest. These inductances feature small parasitic capacitance C such that the characteristic impedance √(L/C) is much larger than the superconducting resistance quantum R Q =h/4e 2 . Superinductances have various applications ranging from qubit designs such as the 0-π qubit or the fluxonium to impedance matching, Bloch oscillations and the stabilization of phase slips in superconducting nanowires. Although there exists a well-established formalism for the quantization of superconducting circuits in terms of node fluxes, this formalism is ill-suited for the description of fast flux transport with localized charges in large-impedance environments. In particular, the nonlinear capacitive behavior of phase slip junctions cannot be modeled in a straightforward way using node fluxes
Results on neutrinoless double beta decay search in GERDA. Background modeling and limit setting
Energy Technology Data Exchange (ETDEWEB)
Becerici Schmidt, Neslihan
2014-07-22
The search for the neutrinoless double beta decay (0νββ) process is primarily motivated by its potential of revealing the possible Majorana nature of the neutrino, in which the neutrino is identical to its antiparticle. It has also the potential to yield information on the intrinsic properties of neutrinos, if the underlying mechanism is the exchange of a light Majorana neutrino. The Gerda experiment is searching for 0νββ decay of {sup 76}Ge by operating high purity germanium (HPGe) detectors enriched in the isotope {sup 76}Ge (∝ 87%), directly in ultra-pure liquid argon (LAr). The first phase of physics data taking (Phase I) was completed in 2013 and has yielded 21.6 kg.yr of data. A background index of B∼10{sup -2} cts/(keV.kg.yr) at Q{sub ββ}=2039 keV has been achieved. A comprehensive background model of the Phase I energy spectrum is presented as the major topic of this dissertation. Decomposition of the background energy spectrum into the individual contributions from different processes provides many interesting physics results. The specific activity of {sup 39}Ar has been determined. The obtained result, A=(1.15±0.11) Bq/kg, is in good agreement with the values reported in literature. The contribution from {sup 42}K decays in LAr to the background spectrum has yielded a {sup 42}K({sup 42}Ar) specific activity of A=(106.2{sub -19.2}{sup +12.7}) μBq/kg, for which only upper limits exist in literature. The analysis of high energy events induced by α decays in the {sup 226}Ra chain indicated a total {sup 226}Ra activity of (3.0±0.9) μBq and a total initial {sup 210}Po activity of (0.18±0.01) mBq on the p{sup +} surfaces of the enriched semi-coaxial HPGe detectors. The half life of the two-neutrino double beta (2νββ) decay of {sup 76}Ge has been determined as T{sub 1/2}{sup 2ν}=(1.926±0.094).10{sup 21} yr, which is in good agreement with the result that was obtained with lower exposure and has been published by the Gerda collaboration
Results on neutrinoless double beta decay search in GERDA. Background modeling and limit setting
International Nuclear Information System (INIS)
Becerici Schmidt, Neslihan
2014-01-01
The search for the neutrinoless double beta decay (0νββ) process is primarily motivated by its potential of revealing the possible Majorana nature of the neutrino, in which the neutrino is identical to its antiparticle. It has also the potential to yield information on the intrinsic properties of neutrinos, if the underlying mechanism is the exchange of a light Majorana neutrino. The Gerda experiment is searching for 0νββ decay of 76 Ge by operating high purity germanium (HPGe) detectors enriched in the isotope 76 Ge (∝ 87%), directly in ultra-pure liquid argon (LAr). The first phase of physics data taking (Phase I) was completed in 2013 and has yielded 21.6 kg.yr of data. A background index of B∼10 -2 cts/(keV.kg.yr) at Q ββ =2039 keV has been achieved. A comprehensive background model of the Phase I energy spectrum is presented as the major topic of this dissertation. Decomposition of the background energy spectrum into the individual contributions from different processes provides many interesting physics results. The specific activity of 39 Ar has been determined. The obtained result, A=(1.15±0.11) Bq/kg, is in good agreement with the values reported in literature. The contribution from 42 K decays in LAr to the background spectrum has yielded a 42 K( 42 Ar) specific activity of A=(106.2 -19.2 +12.7 ) μBq/kg, for which only upper limits exist in literature. The analysis of high energy events induced by α decays in the 226 Ra chain indicated a total 226 Ra activity of (3.0±0.9) μBq and a total initial 210 Po activity of (0.18±0.01) mBq on the p + surfaces of the enriched semi-coaxial HPGe detectors. The half life of the two-neutrino double beta (2νββ) decay of 76 Ge has been determined as T 1/2 2ν =(1.926±0.094).10 21 yr, which is in good agreement with the result that was obtained with lower exposure and has been published by the Gerda collaboration. According to the model, the background in Q ββ ±5 keV window is resulting from close
The Majorana project: sup 7 sup 6 Ge 0 nu beta beta-decay neutrino mass measurement
Aalseth, C E
2002-01-01
Interest in, and the relevance of, next-generation 0 nu beta beta-decay experiments is increasing. Even with nonzero neutrino mass strongly suggested by SNO, Super Kamiokande, and similar experiments sensitive to delta m sup 2 , 0 nu beta beta-decay experiments are still the only way to establish the Dirac or Majorana nature of neutrinos by measuring effective electron neutrino mass, . Various theorists have recently argued in favor of a neutrino mass between 0.01 and 1 eV. The Majorana Project aims to probe this effective neutrino mass range, reaching a sensitivity of 0.02-0.07 eV. The experiment relies entirely on proven technology and has been devised based upon the materials, technology, and data analysis demonstrated to produce the lowest background per kilogram of fiducial germanium. The project plan includes 500 kg of germanium detector material enriched to 85% in sup 7 sup 6 Ge, specialized pulse-acquisition electronics and detector segmentation for background rejection, and underground electroformed ...
Beta decay of {sup 97}Ag: evidence for the Gamow-Teller resonance near {sup 100}Sn
Energy Technology Data Exchange (ETDEWEB)
Hu Zhiqiang
1999-03-01
In two complementary measurements, a cube like array of 6 Euroball-Cluster germanium detectors and a total-absorption {gamma}-spectrometer were used to investigate the {beta} decay of {sup 97}Ag, a three proton-hole nucleus with respect to the {sup 100}Sn core. The half-life and Q{sub EC} value of the decay of the 9/2{sup +} ground-state of {sup 97}Ag were determined to be 25.9(4) s and 6.98(11) MeV respectively. A total of 603 {gamma} rays (578 new) was observed, and 151 levels (132 new) in {sup 97}Pd have been identified. An interesting {beta}-delayed {gamma} cascade was observed, which comprises 6 {gamma}-transitions with a de-excitation pattern involving an initial increase of the level spin. The Gamow-Teller (GT) {beta}-decay strength distributions from the two measurements reveal a large GT resonance around 4 MeV with a width of about 1.8 MeV. The hindrance factor for the total GT strength summed from the ground-state up to 6 MeV excitation energy in {sup 97}Pd, amounts to 4.3(6) with reference to a shell-model prediction. This factor is discussed in comparison with a core-polarization and a Monte-Carlo shell-model calculation. (orig.)
Probing the Dark Sector with Dark Matter Bound States.
An, Haipeng; Echenard, Bertrand; Pospelov, Maxim; Zhang, Yue
2016-04-15
A model of the dark sector where O(few GeV) mass dark matter particles χ couple to a lighter dark force mediator V, m_{V}≪m_{χ}, is motivated by the recently discovered mismatch between simulated and observed shapes of galactic halos. Such models, in general, provide a challenge for direct detection efforts and collider searches. We show that for a large range of coupling constants and masses, the production and decay of the bound states of χ, such as 0^{-+} and 1^{--} states, η_{D} and ϒ_{D}, is an important search channel. We show that e^{+}e^{-}→η_{D}+V or ϒ_{D}+γ production at B factories for α_{D}>0.1 is sufficiently strong to result in multiple pairs of charged leptons and pions via η_{D}→2V→2(l^{+}l^{-}) and ϒ_{D}→3V→3(l^{+}l^{-}) (l=e,μ,π). The absence of such final states in the existing searches performed at BABAR and Belle sets new constraints on the parameter space of the model. We also show that a search for multiple bremsstrahlung of dark force mediators, e^{+}e^{-}→χχ[over ¯]+nV, resulting in missing energy and multiple leptons, will further improve the sensitivity to self-interacting dark matter.
Covariant equations for the three-body bound state
International Nuclear Information System (INIS)
Stadler, A.; Gross, F.; Frank, M.
1997-01-01
The covariant spectator (or Gross) equations for the bound state of three identical spin 1/2 particles, in which two of the three interacting particles are always on shell, are developed and reduced to a form suitable for numerical solution. The equations are first written in operator form and compared to the Bethe-Salpeter equation, then expanded into plane wave momentum states, and finally expanded into partial waves using the three-body helicity formalism first introduced by Wick. In order to solve the equations, the two-body scattering amplitudes must be boosted from the overall three-body rest frame to their individual two-body rest frames, and all effects which arise from these boosts, including Wigner rotations and p-spin decomposition of the shell-particle, are treated exactly. In their final form, the equations reduce to a coupled set of Faddeev-like double integral equations with additional channels arising from the negative p-spin states of the off-shell particle
Dipole-bound states as doorways in (dissociative) electron attachment
International Nuclear Information System (INIS)
Sommerfeld, Thomas
2005-01-01
This communication starts with a comparison of dissociative recombination and dissociative attachment placing emphasis on the role of resonances as reactive intermediates. The main focus is then the mechanism of electron attachment to polar molecules at very low energies (100 meV). The scheme considered consists of two steps: First, an electron is captured in a diffuse dipole-bound state depositing its energy in the vibrational degrees of freedom, in other words, a vibrational Feshbach resonance is formed. Then, owing to the coupling with a valence state, the electron is transferred into a compact valence orbital, and depending on the electron affinities of the valence state and possible dissociation products, as well as on the details of the intramolecular redistribution of vibrational energy, long-lived anions can be generated or dissociation reactions can be initiated. The key property in this context is the electronic coupling strength between the diffuse dipole-bound and the compact valence states. We describe how the coupling strength can be extracted from ab initio data, and present results for Nitromethane, Uracil and Cyanoacetylene
Detection of a π-μ coulomb bound states
International Nuclear Information System (INIS)
Coombes, R.; Flexer, R.; Hall, A.
1977-01-01
The detection of hydrogen-like atoms is reported consisting of a negative (or positive) pion and a positive (or negative) muon in a coulomb bound state. These π-μ atoms are formed when the PI and μ from the decay have sufficiently small relative momentum to bind. Only the evidence related to the detection of these atoms is discussed. The Ksub(L)sup(0) particles which give rise to ''atomic beam'' are produced by 30 GeV proton beam striking a 10 cm beryllium target. From analysis of data 33 events are chosen. For each of these events the parameter α = Psub(π)-Psub(μ)/Psub(π)+Psub(μ) is plotted, where PPI is the pion momentum, and Pμ is the muon momentum. A study of this parameter through an examination of e + e - pairs indicates that the acceptance of apparatus is flat within 30%. The data shows a clear peak at the predicted point containing a total of 21 events with an estimated background of 3 events. The width of the peak is consistent with that expected from measurement errors
Nucleon Viewed as a Borromean Bound-State
Segovia, Jorge; Mezrag, Cédric; Chang, Lei; Roberts, Craig D.
2018-05-01
We explain how the emergent phenomenon of dynamical chiral symmetry breaking ensures that Poincaré covariant analyses of the three valence-quark scattering problem in continuum quantum field theory yield a picture of the nucleon as a Borromean bound-state, in which binding arises primarily through the sum of two separate contributions. One involves aspects of the non-Abelian character of Quantum Chromodynamics that are expressed in the strong running coupling and generate tight, dynamical color-antitriplet quark-quark correlations in the scalar-isoscalar and pseudovector-isotriplet channels. This attraction is magnified by quark exchange associated with diquark breakup and reformation, which is required in order to ensure that each valence-quark participates in all diquark correlations to the complete extent allowed by its quantum numbers. Combining these effects, we arrive at a properly antisymmetrised Faddeev wave function for the nucleon and calculate, e.g. the flavor-separated versions of the Dirac and Pauli form factors and the proton's leading-twist parton distribution amplitude. We conclude that available data and planned experiments are capable of validating the proposed picture.
Recoil effects in the hyperfine structure of QED bound states
International Nuclear Information System (INIS)
Bodwin, G.T.; Yennie, D.R.; Gregorio, M.A.
1985-01-01
The authors give a general discussion of the derivation from field theory of a formalism for the perturbative solution of the relativistic two-body problem. The lowest-order expression for the four-point function is given in terms of a two-particle three-dimensional propagator in a static potential. It is obtained by fixing the loop energy in the four-dimensional formalism at a point which is independent of the loop momentum and is symmetric in the two particle variables. This method avoids awkward positive- and negative-energy projectors, with their attendant energy square roots, and allows one to recover the Dirac equation straightforwardly in the nonrecoil limit. The perturbations appear as a variety of four-dimensional kernels which are rearranged and regrouped into convenient sets. In particular, they are transformed from the Coulomb to the Feynman gauge, which greatly simplifies the expressions that must be evaluated. Although the approach is particularly convenient for the precision analysis of QED bound states, it is not limited to such applications. The authors use it to give the first unified treatment of all presently known recoil corrections to the muonium hyperfine structure and also to verify the corresponding contributions through order α 2 lnαE/sub F/ in positronium. The required integrals are evaluated analytically
On the problem of bound states of pions and neutrons
International Nuclear Information System (INIS)
Gudima, K.K.; Karnaukhov, V.A.
1992-01-01
The problem of existence of the bound states of negative pions and neutrons has been widely discussed for the last years. It is considered possibilities of the experimental observation of pion-neutron clusters, if they do exist, in nucleus-nucleus collisions. The yields of exotic fragments π -Z n A in the interactions of 12 C and 56 Fe with 208 Pb at the energies from 0.3 to 3.7 GeV per nucleon are calculated. For 40 Ar+ 238 U and 139 La+ 238 U collisions the calculations were performed at the energied of 1.8 GeV and 1.3 GeV per nucleon, respectively. These calculations were performed in the framework of the coalescence mechanism with the differential cross sections for pion and neutron production generated by firestreak model. The differential cross sections for production of π -1 n -2 , π -2 N 2 , π - n 4 , π -4 n 6 , and π -12 n 6 were calculated. It is shown that the use of very heavy projectiles like 56 Fe and 139 La has a great advantage in the experimental search for the exotic clusters. 20 refs.; 8 figs
Variational energy for Θ+ - 2H bound state
International Nuclear Information System (INIS)
Shoeb, Mohammad; Naz, Tabassum; Siddiqah, Mariyah
2015-01-01
Pentaquark is considered to be a exotic particle with valency structure of four quarks and antiquark. Diakonov et. al. have made a prediction for the existence of strangeness S= +1 and isospin zero pentaquark Θ + (uudds¯) of mass 1.54 GeV with a narrow width and j p = 1/2 + which is a member of an antidecuplet. Small width is assumed to be a consequence of even parity. We may point out that many experimental searches for the existence of Θ + that have been made in the past have remained inconclusive. Miller has proposed a schematic model where coherent interaction of us¯ and ds¯ pairs leads to very large attractive residual interaction which in turn produces a strongly attractive Θ-nucleon spin-independent local potential, sufficient to produce a bound state of Θ-nuclear matter that is stable against strong decay. In the model under discussion the Θ has been regarded as a collective vibration of nucleon
Majorana bound states in a coupled quantum-dot hybrid-nanowire system
DEFF Research Database (Denmark)
Deng, M. T.; Vaitiekenas, S.; Hansen, E. B.
2016-01-01
Hybrid nanowires combining semiconductor and superconductor materials appear well suited for the creation, detection, and control of Majorana bound states (MBSs). We demonstrate the emergence of MBSs from coalescing Andreev bound states (ABSs) in a hybrid InAs nanowire with epitaxial Al, using...... with the end-dot bound state, which is in agreement with a numerical model. The ABS/MBS spectra provide parameters that are useful for understanding topological superconductivity in this system....
Bound state and localization of excitation in many-body open systems
Cui, H. T.; Shen, H. Z.; Hou, S. C.; Yi, X. X.
2018-04-01
We study the exact bound state and time evolution for single excitations in one-dimensional X X Z spin chains within a non-Markovian reservoir. For the bound state, a common feature is the localization of single excitations, which means the spontaneous emission of excitations into the reservoir is prohibited. Exceptionally, the pseudo-bound state can be found, for which the single excitation has a finite probability of emission into the reservoir. In addition, a critical energy scale for bound states is also identified, below which only one bound state exists, and it is also the pseudo-bound state. The effect of quasirandom disorder in the spin chain is also discussed; such disorder induces the single excitation to locate at some spin sites. Furthermore, to display the effect of bound state and disorder on the preservation of quantum information, the time evolution of single excitations in spin chains is studied exactly. An interesting observation is that the excitation can stay at its initial location with high probability only when the bound state and disorder coexist. In contrast, when either one of them is absent, the information of the initial state can be erased completely or becomes mixed. This finding shows that the combination of bound state and disorder can provide an ideal mechanism for quantum memory.
Energy Technology Data Exchange (ETDEWEB)
Konrad, Gertrud Emilie
2012-01-24
Free neutron decay, n{yields}pe anti {nu}{sub e}, is the simplest nuclear beta decay, well described as a purely left-handed, vector minus axial-vector interaction within the framework of the Standard Model (SM) of elementary particles and fields. Due to its highly precise theoretical description, neutron beta decay data can be used to test certain extensions to the SM. Possible extensions require, e.g., new symmetry concepts like left-right symmetry, new particles, leptoquarks, supersymmetry, or the like. Precision measurements of observables in neutron beta decay address important open questions of particle physics and cosmology, and are generally complementary to direct searches for new physics beyond the SM in high-energy physics. In this doctoral thesis, a measurement of the proton recoil spectrum with the neutron decay spectrometer aSPECT is described. From the proton spectrum the antineutrinoelectron angular correlation coefficient a can be derived. In our first beam time at the Forschungs-Neutronenquelle Heinz Maier-Leibnitz in Munich, Germany (2005-2006), background instabilities due to particle trapping and the electronic noise level of the proton detector prevented us from presenting a new value for a. In the latest beam time at the Institut Laue-Langevin (ILL) in Grenoble, France (2007-2008), the trapped particle background has been reduced sufficiently and the electronic noise problem has essentially been solved. For the first time, a silicon drift detector was used. As a result of the data analysis, we identified and fixed a problem in the detector electronics which caused a significant systematic error. The target figure of the latest beam time was a new value for a with a total relative error well below the present literature value of 4 %. A statistical accuracy of about 1.4% was reached, but we could only set upper limits on the correction of the problem in the detector electronics, which are too high to determine a meaningful result. The present
International Nuclear Information System (INIS)
Konrad, Gertrud Emilie
2012-01-01
Free neutron decay, n→pe anti ν e , is the simplest nuclear beta decay, well described as a purely left-handed, vector minus axial-vector interaction within the framework of the Standard Model (SM) of elementary particles and fields. Due to its highly precise theoretical description, neutron beta decay data can be used to test certain extensions to the SM. Possible extensions require, e.g., new symmetry concepts like left-right symmetry, new particles, leptoquarks, supersymmetry, or the like. Precision measurements of observables in neutron beta decay address important open questions of particle physics and cosmology, and are generally complementary to direct searches for new physics beyond the SM in high-energy physics. In this doctoral thesis, a measurement of the proton recoil spectrum with the neutron decay spectrometer aSPECT is described. From the proton spectrum the antineutrinoelectron angular correlation coefficient a can be derived. In our first beam time at the Forschungs-Neutronenquelle Heinz Maier-Leibnitz in Munich, Germany (2005-2006), background instabilities due to particle trapping and the electronic noise level of the proton detector prevented us from presenting a new value for a. In the latest beam time at the Institut Laue-Langevin (ILL) in Grenoble, France (2007-2008), the trapped particle background has been reduced sufficiently and the electronic noise problem has essentially been solved. For the first time, a silicon drift detector was used. As a result of the data analysis, we identified and fixed a problem in the detector electronics which caused a significant systematic error. The target figure of the latest beam time was a new value for a with a total relative error well below the present literature value of 4 %. A statistical accuracy of about 1.4% was reached, but we could only set upper limits on the correction of the problem in the detector electronics, which are too high to determine a meaningful result. The present doctoral
$\\beta$-decay half-life of $^{70}$Kr a bridge nuclide for the rp-process beyond A = 70
Oinonen, M; Jokinen, A; Baumann, P; Didierjean, François; Huck, A; Knipper, A; Ramdhane, M; Walter, G; Van Duppen, P; Huyse, M; Marguier, G; Novikov, Yu N; Popov, A; Seliverstov, D M; Schatz, H
2000-01-01
The $\\beta$-decay half-life of $^{70}$Kr has been measured for the first time at the ISOLDE PSB Facility at CERN. Mass separated $^{70}$Kr ions were produced by 1 GeV proton induced spallation reactions in a Nb foil. The measured half-life is 57(21) ms. This value is consistent with the half-life calculated assuming a pure Fermi decay, but is clearly lower than the value used in a recent rp-process reaction flow calculation. The result shows that the reaction flow via two-proton-capture of $^{68}$Se is 2.5 times faster than previously calculated assuming an astrophysical temperature of 1.5 GK and a density of 10$^{6}$g/cm$^{3}$.
Energy Technology Data Exchange (ETDEWEB)
Lopez-Pavon, J. [SISSA and INFN - sezione di Trieste, via Bonomea 265, 34136 Trieste (Italy); Molinaro, E. [CP-Origins and Danish Institute for Advanced Study, University of Southern Denmark,Campusvej 55, DK-5230 Odense M (Denmark); Petcov, S.T. [SISSA and INFN - sezione di Trieste, via Bonomea 265, 34136 Trieste (Italy); Kavli IPMU (WPI), University of Tokyo, 5-1-5 Kashiwanoha, 277-8583 Kashiwa (Japan)
2015-11-05
We perform a detailed analysis of the one-loop corrections to the light neutrino mass matrix within low scale type I seesaw extensions of the Standard Model and their implications in experimental searches for neutrinoless double beta decay. We show that a sizable contribution to the effective Majorana neutrino mass from the exchange of heavy Majorana neutrinos is always possible, provided one requires a fine-tuned cancellation between the tree-level and one-loop contribution to the light neutrino masses. We quantify the level of fine-tuning as a function of the seesaw parameters and introduce a generalisation of the Casas-Ibarra parametrization of the neutrino Yukawa matrix, which easily allows to include the one-loop corrections to the light neutrino masses.
Artusa, D. R.; Balzoni, A.; Beeman, J. W.; Bellini, F.; Biassoni, M.; Brofferio, C.; Camacho, A.; Capelli, S.; Cardani, L.; Carniti, P.; Casali, N.; Cassina, L.; Clemenza, M.; Cremonesi, O.; Cruciani, A.; D'Addabbo, A.; Dafinei, I.; Di Domizio, S.; di Vacri, M. L.; Ferroni, F.; Gironi, L.; Giuliani, A.; Gotti, C.; Keppel, G.; Maino, M.; Mancuso, M.; Martinez, M.; Morganti, S.; Nagorny, S. S.; Nastasi, M.; Nisi, S.; Nones, C.; Orlandi, D.; Pagnanini, L.; Pallavicini, M.; Palmieri, V.; Pattavina, L.; Pavan, M.; Pessina, G.; Pettinacci, V.; Pirro, S.; Pozzi, S.; Previtali, E.; Puiu, A.; Rusconi, C.; Schäffner, K.; Tomei, C.; Vignati, M.; Zolotarova, A.
2017-09-01
Future experiments on neutrinoless double beta-decay with the aim of exploring the inverted hierarchy region have to employ detectors with excellent energy resolution and zero background in the energy region of interest. Cryogenic scintillating bolometers turn out to be a suitable candidate since they offer particle discrimination: the dual channel detection of the heat and the scintillation light signal allows for particle identification. In particular such detectors permit for a suppression of α-induced backgrounds, a key-issue for next-generation tonne-scale bolometric experiments. We report on the progress and current status of the LUCIFER/CUPID-0 demonstrator, the first array of scintillating bolometers based on enriched Zn82Se crystals which is expected to start data taking in 2016 and the potential of this detection technique for a future tonne-scale bolometric experiment after CUORE.
Energy Technology Data Exchange (ETDEWEB)
Liu, Zhen, E-mail: liu-zhen@sjtu.edu.cn; Gu, Pei-Hong, E-mail: peihong.gu@sjtu.edu.cn
2017-02-15
We extend some two Higgs doublet models, where the Yukawa couplings for the charged fermion mass generation only involve one Higgs doublet, by two singlet scalars respectively carrying a singly electric charge and a doubly electric charge. The doublet and singlet scalars together can mediate a two-loop diagram to generate a tiny Majorana mass matrix of the standard model neutrinos. Remarkably, the structure of the neutrino mass matrix is fully determined by the symmetric Yukawa couplings of the doubly charged scalar to the right-handed leptons. Meanwhile, a one-loop induced neutrinoless double beta decay can arrive at a testable level even if the electron neutrino has an extremely small Majorana mass. We also study other experimental constraints and implications including some rare processes and Higgs phenomenology.
Directory of Open Access Journals (Sweden)
Zhen Liu
2017-02-01
Full Text Available We extend some two Higgs doublet models, where the Yukawa couplings for the charged fermion mass generation only involve one Higgs doublet, by two singlet scalars respectively carrying a singly electric charge and a doubly electric charge. The doublet and singlet scalars together can mediate a two-loop diagram to generate a tiny Majorana mass matrix of the standard model neutrinos. Remarkably, the structure of the neutrino mass matrix is fully determined by the symmetric Yukawa couplings of the doubly charged scalar to the right-handed leptons. Meanwhile, a one-loop induced neutrinoless double beta decay can arrive at a testable level even if the electron neutrino has an extremely small Majorana mass. We also study other experimental constraints and implications including some rare processes and Higgs phenomenology.
Threshold energy dependence as a function of potential strength and the nonexistence of bound states
International Nuclear Information System (INIS)
Aronson, I.; Kleinman, C.J.; Spruch, L.
1975-01-01
The difficulty in attempting to prove that a given set of particles cannot form a bound state is the absence of a margin of error; the possibility of a bound state of arbitrarily small binding energy must be ruled out. At the sacrifice of rigor, one can hope to bypass the difficulty by studying the ground-state energy E(lambda) associated with H(lambda) identical with H/sub true/ + lambda/sub ν/, where H/sub true/ is the true Hamiltonian, ν is an artificial attractive potential, and lambda greater than 0. E(lambda) can be estimated via a Rayleigh-Ritz calculation. If H/sub true/ falls just short of being able to support a bound state, H(lambda) for lambda ''not too small'' will support a bound state of some significant binding. A margin of error is thereby created; the inability to find a bound state for lambda ''not too small'' suggests not only that H(lambda) can support at best a weakly bound state but that H/sub true/ cannot support a bound state at all. To give the argument real substance, one studies E(lambda) in the neighborhood of lambda = lambda 0 , the (unknown) smallest value for lambda for which H(lambda) can support a bound state. A comparison of E(lambda) determined numerically with the form of E(lambda) obtained with the use of a crude bound-state wave function in the Feynman theorem gives a rough self-consistency check. One thereby obtains a believable lower bound on the energy of a possible bound state of H/sub true/ or a believable argument that no such bound state exists. The method is applied to the triplet state of H -
Andreev bound states probed in three-terminal quantum dots
Gramich, J.; Baumgartner, A.; Schönenberger, C.
2017-11-01
Andreev bound states (ABSs) are well-defined many-body quantum states that emerge from the hybridization of individual quantum dot (QD) states with a superconductor and exhibit very rich and fundamental phenomena. We demonstrate several electron transport phenomena mediated by ABSs that form on three-terminal carbon nanotube (CNT) QDs, with one superconducting (S) contact in the center and two adjacent normal-metal (N) contacts. Three-terminal spectroscopy allows us to identify the coupling to the N contacts as the origin of the Andreev resonance (AR) linewidths and to determine the critical coupling strengths to S, for which a ground state (or quantum phase) transition in such S-QD systems can occur. In addition, we ascribe replicas of the lowest-energy ABS resonance to transitions between the ABS and odd-parity excited QD states, a process we call excited state ABS resonances. In the conductance between the two N contacts we find a characteristic pattern of positive and negative differential subgap conductance, which we explain by considering two nonlocal processes, the creation of Cooper pairs in S by electrons from both N terminals, and a transport mechanism we call resonant ABS tunneling, possible only in multiterminal QD devices. In the latter process, electrons are transferred via the ABS without effectively creating Cooper pairs in S. The three-terminal geometry also allows spectroscopy experiments with different boundary conditions, for example by leaving S floating. Surprisingly, we find that, depending on the boundary conditions and the device parameters, the experiments either show single-particle Coulomb blockade resonances, ABS characteristics, or both in the same measurements, seemingly contradicting the notion of ABSs replacing the single-particle states as eigenstates of the QD. We qualitatively explain these results as originating from the finite time scale required for the coherent oscillations between the superposition states after a single
Systematic assignment of Feshbach resonances via an asymptotic bound state model
Goosen, M.; Kokkelmans, SJ.J.M.F.
2008-01-01
We present an Asymptotic Bound state Model (ABM), which is useful to predict Feshbach resonances. The model utilizes asymptotic properties of the interaction potentials to represent coupled molecular wavefunctions. The bound states of this system give rise to Feshbach resonances, localized at the
Bound states and scattering coefficients of the -aδ(x)+bδ'(x) potential
International Nuclear Information System (INIS)
Gadella, M.; Negro, J.; Nieto, L.M.
2009-01-01
We show that a one-dimensional Schroedinger equation in which the potential is a delta well plus a δ ' interaction at the same point has a bound state, and we obtain the energy of this bound state in terms of the parameters. In addition, the expression of the reflection and transmission coefficients is also fully determined
A study of the bound states for square potential wells with position-dependent mass
International Nuclear Information System (INIS)
Ganguly, A.; Kuru, S.; Negro, J.; Nieto, L.M.
2006-01-01
A potential well with position-dependent mass is studied for bound states. Applying appropriate matching conditions, a transcendental equation is derived for the energy eigenvalues. Numerical results are presented graphically and the variation of the energy of the bound states are calculated as a function of the well-width and mass
A low-lying long-lived (26±1 ms) isomer in $^{34}$Al has been observed recently and assigned as 1$^{+}$ state of intruder character. It was populated in $^{36}$S fragmentation and feeds, in $\\beta$-decay, the 0$_{2}^{+}$ state in $^{34}$Si whose excitation energy and lifetime were determined in an electron-positron pairs spectroscopy experiment. In the present experiment we intend to measure for the first time the $\\gamma$-rays following the $\\beta$-decay of $^{34}$Mg. Despite the interest for $^{34}$Mg, the up-right corner of the “N$\\thicksim$20 island of inversion”, the only information on its $\\beta$-decay is the lifetime of 20±10 ms, determined from $\\beta$-neutron coincidences. As a result of the proposed experiment, we expect to place the first transitions in the level scheme of $^{34}$Al and to strongly populate the newly observed isomer, measuring its excitation energy, if the branching ratio to 4$^{−}$ ground state is significant. Theoretical estimations for the $\\beta$-decay of the new isome...
Energy Technology Data Exchange (ETDEWEB)
Kidd, M.F.; Esterline, J.H. [Department of Physics, Duke University and Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States); Tornow, W. [Department of Physics, Duke University and Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States)], E-mail: tornow@tunl.duke.edu; Barabash, A.S.; Umatov, V.I. [Institute for Theoretical and Experimental Physics, 117259 Moscow (Russian Federation)
2009-04-15
The coincidence detection efficiency of the TUNL-ITEP apparatus designed for measuring half-life times of two-neutrino double-beta (2{nu}{beta}{beta}) decay transitions to excited final states in daughter nuclei has been measured with a factor of 2.4 improved accuracy. In addition, the previous measuring time of 455 days for the study of the {sup 100}Mo 2{nu}{beta}{beta} decay to the first excited 0{sub 1}{sup +} state in {sup 100}Ru has been increased by 450 days, and a new result (combined with the previous measurement obtained with the same apparatus) for this transition is presented: T{sub 1/2}=[5.5{sub -0.8}{sup +1.2}(stat){+-}0.3(syst)]x10{sup 20} yr. Measured 2{nu}{beta}{beta} decay half-life times to excited states can be used to test the reliability of nuclear matrix element calculations needed for determining the effective neutrino mass from zero-neutrino double-beta decay data. We also present new limits for transitions to higher excited states in {sup 100}Ru which, if improved, may be of interest for more exotic conjectures, like a bosonic component to neutrino statistics.
Energy Technology Data Exchange (ETDEWEB)
Irastorza, I.G.; Aznar, F.; Castel, J., E-mail: igor.irastorza@cern.ch, E-mail: faznar@unizar.es, E-mail: jfcastel@unizar.es [Grupo de Física Nuclear y Astropartículas, Departamento de Física Teórica, Universidad de Zaragoza, C/ P. Cerbuna 12, Zaragoza, 50009 (Spain); and others
2016-01-01
As part of the T-REX project, a number of R and D and prototyping activities have been carried out during the last years to explore the applicability of gaseous Time Projection Chambers (TPCs) with Micromesh Gas Structures (Micromegas) in rare event searches like double beta decay, axion research and low-mass WIMP searches. In both this and its companion paper, we compile the main results of the project and give an outlook of application prospects for this detection technique. While in the companion paper we focus on axions and WIMPs, in this paper we focus on the results regarding the measurement of the double beta decay (DBD) of {sup 136}Xe in a high pressure Xe (HPXe) TPC. Micromegas of the microbulk type have been extensively studied in high pressure Xe and Xe mixtures. Particularly relevant are the results obtained in Xe + trimethylamine (TMA) mixtures, showing very promising results in terms of gain, stability of operation, and energy resolution at high pressures up to 10 bar. The addition of TMA at levels of ∼ 1% reduces electron diffusion by up to a factor of 10 with respect to pure Xe, improving the quality of the topological pattern, with a positive impact on the discrimination capability. Operation with a medium size prototype of 30 cm diameter and 38 cm of drift (holding about 1 kg of Xe at 10 bar in the fiducial volume, enough to contain high energy electron tracks in the detector volume) has allowed to test the detection concept in realistic experimental conditions. Microbulk Micromegas are able to image the DBD ionization signature with high quality while, at the same time, measuring its energy deposition with a resolution of at least a ∼ 3% FWHM @ Q{sub ββ}. This value was experimentally demonstrated for high-energy extended tracks at 10 bar, and is probably improvable down to the ∼ 1% FWHM levels as extrapolated from low energy events. In addition, first results on the topological signature information (one straggling track ending in two
Gruszko, Julieta
Though the existence of neutrino oscillations proves that neutrinos must have non-zero mass, Beyond-the-Standard-Model physics is needed to explain the origins of that mass. One intriguing possibility is that neutrinos are Majorana particles, i.e., they are their own anti-particles. Such a mechanism could naturally explain the observed smallness of the neutrino masses, and would have consequences that go far beyond neutrino physics, with implications for Grand Unification and leptogenesis. If neutrinos are Majorana particles, they could undergo neutrinoless double-beta decay (0nBB), a hypothesized rare decay in which two antineutrinos annihilate one another. This process, if it exists, would be exceedingly rare, with a half-life over 1E25 years. Therefore, searching for it requires experiments with extremely low background rates. One promising technique in the search for 0nBB is the use of P-type point-contact (P-PC) high-purity Germanium (HPGe) detectors enriched in 76Ge, operated in large low-background arrays. This approach is used, with some key differences, by the MAJORANA and GERDA Collaborations. A problematic background in such large granular detector arrays is posed by alpha particles incident on the surfaces of the detectors, often caused by 222Rn contamination of parts or of the detectors themselves. In the MAJORANA DEMONSTRATOR, events have been observed that are consistent with energy-degraded alphas originating near the passivated surface of the detectors, leading to a potential background contribution in the region-of-interest for neutrinoless double-beta decay. However, it is also observed that when energy deposition occurs very close to the passivated surface, high charge trapping occurs along with subsequent slow charge re-release. This leads to both a reduced prompt signal and a measurable change in slope of the tail of a recorded pulse. Here we discuss the characteristics of these events and the development of a filter that can identify the
Two-vibron bound states in the β–Fermi–Pasta–Ulam model
International Nuclear Information System (INIS)
Hu Xinguang; Tang Yi
2008-01-01
This paper studies the two-vibron bound states in the β–Fermi–Pasta–Ulam model by means of the number conserving approximation combined with the number state method. The results indicate that on-site, adjacent-site and mixed two-vibron bound states may exist in the model. Specially, wave number has a significant effect on such bound states, which may be considered as the quantum effects of the localized states in quantum systems. (condensed matter: structure, thermal and mechanical properties)
Accidental bound states in the continuum in an open Sinai billiard
Energy Technology Data Exchange (ETDEWEB)
Pilipchuk, A.S. [Kirensky Institute of Physics, Federal Research Center KSC SB RAS, 660036 Krasnoyarsk (Russian Federation); Siberian Federal University, 660080 Krasnoyarsk (Russian Federation); Sadreev, A.F., E-mail: almas@tnp.krasn.ru [Kirensky Institute of Physics, Federal Research Center KSC SB RAS, 660036 Krasnoyarsk (Russian Federation)
2017-02-19
The fundamental mechanism of the bound states in the continuum is the full destructive interference of two resonances when two eigenlevels of the closed system are crossing. There is, however, a wide class of quantum chaotic systems which display only avoided crossings of eigenlevels. As an example of such a system we consider the Sinai billiard coupled with two semi-infinite waveguides. We show that notwithstanding the absence of degeneracy bound states in the continuum occur due to accidental decoupling of the eigenstates of the billiard from the waveguides. - Highlights: • Bound states in the continuum in open chaotic billiards occur to accidental vanishing of coupling of eigenstate of billiard with waveguides.
Relativistic bound-state problem of a one-dimensional system
International Nuclear Information System (INIS)
Sato, T.; Niwa, T.; Ohtsubo, H.; Tamura, K.
1991-01-01
A Poincare-covariant description of the two-body bound-state problem in one-dimensional space is studied by using the relativistic Schrodinger equation. We derive the many-body Hamiltonian, electromagnetic current and generators of the Poincare group in the framework of one-boson exchange. Our theory satisfies Poincare algebra within the one-boson-exchange approximation. We numerically study the relativistic effects on the bound-state wavefunction and the elastic electromagnetic form factor. The Lorentz boost of the bound-state wavefunction and the two-body exchange current are shown to play an important role in guaranteeing the Lorentz invariance of the form factor. (author)
Bound states embedded into continuous spectrum as 'gathered' (compactified) scattering waves
International Nuclear Information System (INIS)
Zakhar'ev, B.N.; Chabanov, V.M.
1995-01-01
It is shown that states of continuous spectrum (the half-line case) can be considered as bound states normalized by unity but distributed on the infinite interval with vanishing density. Then the algorithms of shifting the range of primary localization of a chosen bound state in potential well of finite width appear to be applicable to scattering functions. The potential perturbations of the same type (but now on half-axis) concentrate the scattering wave in near vicinity of the origin, which leads to creation of bound state embedded into continuous spectrum. (author). 8 refs., 7 figs
Tunable hybridization of Majorana bound states at the quantum spin Hall edge
Keidel, Felix; Burset, Pablo; Trauzettel, Björn
2018-02-01
Confinement at the helical edge of a topological insulator is possible in the presence of proximity-induced magnetic (F) or superconducting (S) order. The interplay of both phenomena leads to the formation of localized Majorana bound states (MBS) or likewise (under certain resonance conditions) the formation of ordinary Andreev bound states (ABS). We investigate the properties of bound states in junctions composed of alternating regions of F or S barriers. Interestingly, the direction of magnetization in F regions and the relative superconducting phase between S regions can be exploited to hybridize MBS or ABS at will. We show that the local properties of MBS translate into a particular nonlocal superconducting pairing amplitude. Remarkably, the symmetry of the pairing amplitude contains information about the nature of the bound state that it stems from. Hence this symmetry can in principle be used to distinguish MBS from ABS, owing to the strong connection between local density of states and nonlocal pairing in our setup.
Applications of the infinite momentum method to quantum electrodynamics and bound state problem
International Nuclear Information System (INIS)
Brodsky, S.J.
1973-01-01
It is shown that the infinite momentum method is a valid and useful calculational alternative to standard perturbation theory methods. The most exciting future applications may be in bound state problems in quantum electrodynamics
Klapdor-Kleingrothaus, H V
2001-01-01
Double beta decay is indispensable to solve the question of the neutrino mass matrix together with nu oscillation experiments. The most sensitive experiment for eight years-the HEIDELBERG-MOSCOW experiment in Gran-Sasso-already now, with the experimental limit of (m/sub nu /)<0.26 eV excludes degenerate nu mass scenarios allowing neutrinos as hot dark matter in the Universe for the small angle MSW solution of the solar neutrino problem. It probes cosmological models including hot dark matter already now on the level of future satellite experiments MAP and PLANCK. It further probes many topics of beyond standard model physics at the TeV scale. Future experiments should give access to the multiTeV range and complement on many ways the search for new physics at future colliders like LHC and NLC. For neutrino physics GENIUS will allow to test almost all neutrino mass scenarios allowed by the present neutrino oscillation experiments. At the same time GENIUS will cover a wide range of the parameter space of pred...
Chen, Xun; Fu, ChangBo; Galan, Javier; Giboni, Karl; Giuliani, Franco; Gu, LingHui; Han, Ke; Ji, XiangDong; Lin, Heng; Liu, JiangLai; Ni, KaiXiang; Kusano, Hiroki; Ren, XiangXiang; Wang, ShaoBo; Yang, Yong; Zhang, Dan; Zhang, Tao; Zhao, Li; Sun, XiangMing; Hu, ShouYang; Jian, SiYu; Li, XingLong; Li, XiaoMei; Liang, Hao; Zhang, HuanQiao; Zhao, MingRui; Zhou, Jing; Mao, YaJun; Qiao, Hao; Wang, SiGuang; Yuan, Ying; Wang, Meng; Khan, Amir N.; Raper, Neill; Tang, Jian; Wang, Wei; Dong, JiaNing; Feng, ChangQing; Li, Cheng; Liu, JianBei; Liu, ShuBin; Wang, XiaoLian; Zhu, DanYang; Castel, Juan F.; Cebrián, Susana; Dafni, Theopisti; Garza, Javier G.; Irastorza, Igor G.; Iguaz, Francisco J.; Luzón, Gloria; Mirallas, Hector; Aune, Stephan; Berthoumieux, Eric; Bedfer, Yann; Calvet, Denis; d'Hose, Nicole; Delbart, Alain; Diakaki, Maria; Ferrer-Ribas, Esther; Ferrero, Andrea; Kunne, Fabienne; Neyret, Damien; Papaevangelou, Thomas; Sabatié, Franck; Vanderbroucke, Maxence; Tan, AnDi; Haxton, Wick; Mei, Yuan; Kobdaj, Chinorat; Yan, Yu-Peng
2017-06-01
Searching for the neutrinoless double beta decay (NLDBD) is now regarded as the topmost promising technique to explore the nature of neutrinos after the discovery of neutrino masses in oscillation experiments. PandaX-III (particle and astrophysical xenon experiment III) will search for the NLDBD of 136Xe at the China Jin Ping Underground Laboratory (CJPL). In the first phase of the experiment, a high pressure gas Time Projection Chamber (TPC) will contain 200 kg, 90% 136Xe enriched gas operated at 10 bar. Fine pitch micro-pattern gas detector (Microbulk Micromegas) will be used at both ends of the TPC for the charge readout with a cathode in the middle. Charge signals can be used to reconstruct the electron tracks of the NLDBD events and provide good energy and spatial resolution. The detector will be immersed in a large water tank to ensure 5 m of water shielding in all directions. The second phase, a ton-scale experiment, will consist of five TPCs in the same water tank, with improved energy resolution and better control over backgrounds.
Beta-decay study of T{sub z}=-2 proton-rich nucleus {sup 24}Si
Energy Technology Data Exchange (ETDEWEB)
Ichikawa, Y.; Iwasaki, H.; Nakao, T.; Ong, H.J.; Onishi, T.K.; Suzuki, D.; Suzuki, H.; Suzuki, M.K. [University of Tokyo, Department of Physics, Tokyo (Japan); Kubo, T.; Aoi, N.; Fukuda, N.; Motobayashi, T.; Yamada, K.N.; Sakurai, H. [RIKEN, RIKEN Nishina Center, Saitama (Japan); Banerjee, V.; Chakrabarti, A. [Variable Energy Cyclotron Centre, Kolkata (India); Kubono, S.; Yamaguchi, H. [University of Tokyo, Center for Nuclear Study, Tokyo (Japan); Nakabayashi, T.; Nakamura, T.; Okumura, T. [Tokyo Institute of Technology, Department of Physics, Tokyo (Japan); Teranishi, T. [Kyushu University, Department of Physics, Fukuoka (Japan)
2009-12-15
{beta} -decay spectroscopy on a T{sub z}=-2 proton-rich nucleus {sup 24}Si was performed. The decay scheme of {sup 24}Si was reconstructed by the {beta} -delayed {gamma} -ray and proton measurements. Two {beta} branches to the bound 1{sub 1}{sup +} and 1{sub 2}{sup +} states in {sup 24}Al were observed for the first time. The observation of the allowed transition firmly established the spin-parity assignment for the 1{sub 2}{sup +} states. The branching ratios to the 1{sub 1}{sup +} and 1{sub 2}{sup +} states were determined to be 31(4)% and 23.9(15)%, respectively. The branching ratios to three unbound states in {sup 24}Al including a new level at 6.735MeV were also determined for the first time. The level structure of {sup 24}Al was compared with its mirror nucleus {sup 24}Na. The Thomas-Ehrman shift on the 1{sub 2}{sup +} state indicates s -wave dominance in the state as well as a characteristic behavior of the weakly bound s-wave proton in {sup 24}Al. (orig.)
Connection between bound-states of bosons moving in one dimension
International Nuclear Information System (INIS)
Coutinho, F.A.B.
1982-06-01
It is shown that when a system of two identical bosons moving in one dimension have a bound state of energy ν sub(o), then the N body system will also have a bound state at a specific energy given by equation W(N+1) = 2N/1-N ]W(N)] - N+1/1-N ]W(N-1)]. (Author) [pt
On bound states of photons in noncommutative U(1) gauge theory
International Nuclear Information System (INIS)
Fatollahi, A.H.; Jafari, A.
2006-01-01
We consider the possibility that photons of noncommutative U(1) gauge theory can make bound states. Using the potential model, developed based on the constituent gluon picture of QCD glue-balls, arguments are presented in favor of the existence of these bound states. The basic ingredient of the potential model is that the self-interacting massless gauge particles may get mass by the inclusion of non-perturbative effects. (orig.)
Bound states in the two-dimension massive quantum electrodynamics (Qed2)
International Nuclear Information System (INIS)
Alves, V.S.; Gomes, M.
1994-01-01
This work studies the fermion-antifermion bound states in the (1+1)D two-dimension massive quantum electrodynamic in the 1/N expansion. The scattering matrices in the non-relativistic approximation have been calculated through TQC, and compared with the cross section in the Born approximation, and therefore the potential responsible by the interactions in the scattering processes have been obtained. Using Schroedinger equation, the existence of possible bound states have been investigated
Fano effect and Andreev bound states in T-shape double quantum dots
International Nuclear Information System (INIS)
Calle, A.M.; Pacheco, M.; Orellana, P.A.
2013-01-01
In this Letter, we investigate the transport through a T-shaped double quantum dot coupled to two normal metal leads left and right and a superconducting lead. Analytical expressions of Andreev transmission and local density of states of the system at zero temperature have been obtained. We study the role of the superconducting lead in the quantum interferometric features of the double quantum dot. We report for first time the Fano effect produced by Andreev bound states in a side quantum dot. Our results show that as a consequence of quantum interference and proximity effect, the transmission from normal to normal lead exhibits Fano resonances due to Andreev bound states. We find that this interference effect allows us to study the Andreev bound states in the changes in the conductance between two normal leads. - Highlights: • Transport properties of a double quantum dot coupled in T-shape configuration to conducting and superconducting leads are studied. • We report Fano antiresonances in the normal transmission due to the Andreev reflections in the superconducting lead. • We report for first time the Fano effect produced by Andreev bound states in a side quantum dot. • Fano effect allows us to study the Andreev bound states in the changes in the conductance between two normal leads. • Andreev bound states survives even for strong dot-superconductor coupling
Energy Technology Data Exchange (ETDEWEB)
Barabash, A.S.; Konovalov, S.I.; Umatov, V.I. [ITEP, National Research Centre ' ' Kurchatov Institute' ' , Moscow (Russian Federation); Danevich, F.A. [MSP, Institute for Nuclear Research, Kyiv (Ukraine); Gimbal-Zofka, Y. [Univ. Paris-Sud, CNRS/IN2P3, Universite Paris-Saclay, CSNSM, Orsay (France); Linnaeus University, Department of Physics and Electrical Engineering, Kalmar (Sweden); Giuliani, A.; Mancuso, M. [Univ. Paris-Sud, CNRS/IN2P3, Universite Paris-Saclay, CSNSM, Orsay (France); DISAT, Universita dell' Insubria, Como (Italy); Marcillac, P. de; Marnieros, S.; Novati, V.; Olivieri, E. [Univ. Paris-Sud, CNRS/IN2P3, Universite Paris-Saclay, CSNSM, Orsay (France); Nones, C.; Zolotarova, A.S. [DSM/IRFU, CEA Saclay, Gif-sur-Yvette Cedex (France); Poda, D.V. [MSP, Institute for Nuclear Research, Kyiv (Ukraine); Univ. Paris-Sud, CNRS/IN2P3, Universite Paris-Saclay, CSNSM, Orsay (France); Shlegel, V.N. [Nikolaev Institute of Inorganic Chemistry, Novosibirsk (Russian Federation); Tretyak, V.I. [MSP, Institute for Nuclear Research, Kyiv (Ukraine); INFN, Sezione di Roma, Rome (Italy)
2016-09-15
For the first time, a cadmium tungstate crystal scintillator enriched in {sup 116}Cd has been succesfully tested as a scintillating bolometer. The measurement was performed above ground at a temperature of 18 mK. The crystal mass was 34.5 g and the enrichment level ∝ 82 %. Despite a substantial pile-up effect due to above-ground operation, the detector demonstrated high energy resolution (2-7 keV FWHM in 0.2-2.6 MeV γ energy range and 7.5 keV FWHM at the {sup 116}Cd double-beta decay transition energy of 2813 keV), a powerful particle identification capability and a high level of internal radio-purity. These results prove that cadmium tungstate is a promising detector material for a next-generation neutrinoless double-beta decay bolometric experiment, like that proposed in the CUPID project (CUORE Upgrade with Particle IDentification). (orig.)
Beta-decay half-lives and level ordering of sup 1 sup 0 sup 2 sup m sup , sup g Rh
Shibata, M; Itoh, S; Itoh, S; Yamamoto, H; Kawade, K; Kasugai, Y; Ikeda, Y
1998-01-01
Beta-decay half-lives of the ground state and an isomer of sup 1 sup 0 sup 2 Rh have been determined 207.3(17) d and 3.742(10) y, respectively, by gamma-ray decay curves following each beta-decay. It has been found that a state (2 sup -) which has a shorter half-life (207.3 d) is the ground state from the result that the half-life of the 41.9 keV isomeric gamma-transition was equal to 3.742 y. It has also been confirmed that the 41.9 keV transition is certainly an isomeric transition with X-gamma coincidence measurement.
Energy Technology Data Exchange (ETDEWEB)
Angelini, G.; Keheyan, Y.; Lilla, E.; Perez, G. (Consiglio Nazionale delle Ricerche, Rome (Italy). Ist. di Chimica Nucleare)
1990-01-01
Tritiated napththylium ions, generated by spontaneous {beta}-decay of (1,4-{sup 3}H) naphthalene, have been allowed to react with benzene molecules in gaseous and liquid phase. The isomeric phenylnaphthalenes and fluoranthene have been found among the reaction products. The differences between the reactivity pattern of naphthylium ion in the two phases can be explained by the different efficiency of collisional stabilization of the excited reaction intermediates. (orig.).
Shape effects in the vicinity of the Z=82 line: study of the $\\beta$-decay of $^{182,184,186}$Hg
This proposal is aimed at the study of the $\\beta$-decay of the neutron-deficient $^{182,184,186}$Hg nuclei using the total absorption technique. Recent theoretical results show that, from measurements of the Gamow-Teller strength distribution, the shapes of the ground states of the decaying Hg nuclei can be inferred. This study offers an independent way to study the phenomenon of shape coexistence in a region of particular interest.
Energy Technology Data Exchange (ETDEWEB)
Grevy, S. [Laboratoire de Physique Corpusculaire de Caen, IN2P3-CNRS, ENSICAEN et Universite de Caen, F-14050 Caen Cedex (France)]. E-mail: grevy@in2p3.fr; Angelique, J.C.; Baumann, P.; Borcea, C.; Buta, A.; Canchel, G.; Catford, W.N.; Courtin, S.; Daugas, J.M.; Oliveira, F. de; Dessagne, P.; Dlouhy, Z.; Knipper, A.; Kratz, K.L.; Lecolley, F.R.; Lecouey, J.L.; Lehrsenneau, G.; Lewitowicz, M.; Lienard, E.; Lukyanov, S.; Marechal, F.; Miehe, C.; Mrazek, J.; Negoita, F.; Orr, N.A.; Pantelica, D.; Penionzhkevich, Y.; Peter, J.; Pfeiffer, B.; Pietri, S.; Poirier, E.; Sorlin, O.; Stanoiu, M.; Stefan, I.; Stodel, C.; Timis, C
2004-12-27
A {beta}-decay experiment on nuclei in the region of N=28 has been performed at the GANIL facility. New measured half-lives for the Si isotopes from N=25 to N=28 are reported and discussed in the light of the deformation occurring in this region. Comparison with QRPA calculations suggests that a weakening of the spin-orbit force occurs for the very neutron-rich Si isotopes.
Microscopic Calculations of Isospin-Breaking Corrections to Superallowed Beta Decay
International Nuclear Information System (INIS)
Satula, W.; Rafalski, M.; Dobaczewski, J.; Nazarewicz, W.
2011-01-01
The superallowed β-decay rates that provide stringent constraints on physics beyond the standard model of particle physics are affected by nuclear structure effects through isospin-breaking corrections. The self-consistent isospin- and angular-momentum-projected nuclear density functional theory is used for the first time to compute those corrections for a number of Fermi transitions in nuclei from A=10 to A=74. The resulting leading element of the Cabibbo-Kobayashi-Maskawa matrix, |V ud |=0.974 47(23), agrees well with the recent result of Towner and Hardy [Phys. Rev. C 77, 025501 (2008)].
Bound-state β decay of a neutron in a strong magnetic field
International Nuclear Information System (INIS)
Kouzakov, Konstantin A.; Studenikin, Alexander I.
2005-01-01
The β decay of a neutron into a bound (pe - ) state and an antineutrino in the presence of a strong uniform magnetic field (B > or approx. 10 13 G) is considered. The β decay process is treated within the framework of the standard model of weak interactions. A Bethe-Salpeter formalism is employed for description of the bound (pe - ) system in a strong magnetic field. For the field strengths 10 13 18 G the estimate for the ratio of the bound-state decay rate w b and the usual (continuum-state) decay rate w c is derived. It is found that in such strong magnetic fields w b /w c ∼0.1-0.4. This is in contrast to the field-free case, where w b /w c ≅4.2x10 -6 [J. N. Bahcall, Phys. Rev. 124, 495 (1961); L. L. Nemenov, Sov. J. Nucl. Phys. 15, 582 (1972); X. Song, J. Phys. G: Nucl. Phys. 13, 1023 (1987)]. The dependence of the ratio w b /w c on the magnetic field strength B exhibits a logarithmiclike behavior. The obtained results can be important for applications in astrophysics and cosmology
Final report: Accelerated beta decay for disposal of fission fragment wastes
International Nuclear Information System (INIS)
Reiss, Howard R.
2000-01-01
The fundamental theory of the interaction of intense, low-frequency electromagnetic fields with certain radioactive nuclei has been fully formulated. The nuclei are of the type that exists in high-level radioactive wastes that are end products of the production of energy from nuclear fission. The basic physical mechanisms that underlie the coupling of the applied field to the nucleus have been identified. Both the basic theory and numerical predictions that stem from it support the conclusion that high-level radioactive wastes can be disposed of by substantially accelerating the rate of radioactive decay. Some old experiments on the acceleration of this type of radioactivity, with results that were not understood at the time, have been re-examined. Their interpretation is now clear, and the experiments are found to be in agreement with the theory
A proportional chamber to measure the screening potential in sup 3 H beta decay
Paterson, D J; Batkin, I S
1999-01-01
A gas proportional chamber has been assembled to make precise observations of the low-energy region of the sup 3 H beta spectrum. Backgrounds have been measured and understood, and are maintained at approx 2% of the data rate. Wall effects have been simulated for this chamber and are predicted at <0.5% of events. Systematic effects which may introduce errors into the observed spectrum have been carefully measured at a level below approx 10 sup - sup 4 per ADC channel. This apparatus will be used to make precise measurements of the effects of screening of the nuclear charge by orbital electrons on the beta spectrum of sup 3 H, and to attempt to observe the effect of a hypothesized admixture of heavy neutrinos in the sup 3 H spectrum.
Improvement of gross theory of beta-decay for application to nuclear data
Koura, Hiroyuki; Yoshida, Tadashi; Tachibana, Takahiro; Chiba, Satoshi
2017-09-01
A theoretical study of β decay and delayed neutron has been carried out with a global β-decay model, the gross theory. The gross theory is based on a consideration of the sum rule of the β-strength function, and gives reasonable results of β-decay rates and delayed neutron in the entire nuclear mass region. In a fissioning nucleus, neutrons are produced by β decay of neutron-rich fission fragments from actinides known as delayed neutrons. The average number of delayed neutrons is estimated based on the sum of the β-delayed neutron-emission probabilities multiplied by the cumulative fission yield for each nucleus. Such a behavior is important to manipulate nuclear reactors, and when we adopt some new high-burn-up reactors, properties of minor actinides will play an important roll in the system, but these data have not been sufficient. We re-analyze and improve the gross theory. For example, we considered the parity of neutrons and protons at the Fermi surface, and treat a suppression for the allowed transitions in the framework of the gross theory. By using the improved gross theory, underestimated half-lives in the neutron-rich indium isotopes and neighboring region increase, and consequently follow experimental trend. The ability of reproduction (and also prediction) of the β-decay rates, delayed-neutron emission probabilities is discussed. With this work, we have described the development of a programming code of the gross theory of β-decay including the improved parts. After preparation finished, this code can be released for the nuclear data community.
Quark-antiquark bound-state spectroscopy and QCD
International Nuclear Information System (INIS)
Bloom, E.D.
1982-11-01
The discussion covers quarks as we know them, the classification of ordinary mesons in terms of constituent quarks, hidden charm states and charmed mesons, bottom quarks, positronium as a model for quarti q, quantum chromodynamics and its foundation in experiment, the charmonium model, the mass of states, fine structure and hyperfine structure, classification, widths of states, rate and multipolarity of gamma transitions, questions about bottom, leptonic widths and the determination of Q/sub b/, the mass splitting of the n 3 S 1 states, the center of gravity of the masses of the n 3 P; states, n 3 P; fine structure and classification, branching ratios for upsilon' → tau chi/sub 6j/ and the tau cascade reactions, hyperfine splitting, and top
Quark-antiquark bound-state spectroscopy and QCD
Energy Technology Data Exchange (ETDEWEB)
Bloom, E.D.
1982-11-01
The discussion covers quarks as we know them, the classification of ordinary mesons in terms of constituent quarks, hidden charm states and charmed mesons, bottom quarks, positronium as a model for quarti q, quantum chromodynamics and its foundation in experiment, the charmonium model, the mass of states, fine structure and hyperfine structure, classification, widths of states, rate and multipolarity of gamma transitions, questions about bottom, leptonic widths and the determination of Q/sub b/, the mass splitting of the n/sup 3/S/sub 1/ states, the center of gravity of the masses of the n/sup 3/P; states, n/sup 3/ P; fine structure and classification, branching ratios for upsilon' ..-->.. tau chi/sub 6j/ and the tau cascade reactions, hyperfine splitting, and top. (GHT)
Double Beta Decay with Ge-detectors - and the future of Double Beta and Dark Matter Search (GENIUS)
International Nuclear Information System (INIS)
Klapdor-Kleingrothaus, H.V.
1999-01-01
Nuclear double beta decay provides an extraordinarily broad potential to search for beyond Standard Model physics, probing already now the TeV scale, on which new physics should manifest itself. These possibilities are reviewed here. First, the results of present generation experiments are presented. The most sensitive one of them - the Heidelberg-Moscow experiment in the Gran Sasso, using enriched 76 Ge - probes the electron neutrino mass now in the sub eV region and will reach a limit of ∼ 0.1 eV in a few years. Basing to a large extent on the theoretical work of the Heidelberg Double Beta Group in the last two years, results are obtained also for SUSY models (R-parity breaking, sneutrino mass), leptoquarks (leptoquark-Higgs coupling), compositeness, right-handed W boson mass and others. These results are comfortably competitive to corresponding results from high-energy accelerators like TEVATRON, HERA, etc. Second, future perspectives of ββ research are discussed. A new Heidelberg experimental proposal (GENIUS) is presented which would allow to increase the sensitivity for Majorana neutrino masses from the present level of at best 0.1 eV down to 0.01 or even 0.001 eV. Its physical potential would be a breakthrough into the multi-TeV range for many beyond standard models. Its sensitivity for neutrino oscillation parameters would be larger than of all present terrestrial neutrino oscillation experiments and of those planned for the future. It would further, already in a first step, cover almost the full MSSM parameter space for prediction of neutralinos as cold dark matter, making the experiment competitive to LHC in the search for supersymmetry
Girardi, I.; Petcov, S. T.; Titov, A. V.
2016-10-01
We obtain predictions for the Majorana phases α21 / 2 and α31 / 2 of the 3 × 3 unitary neutrino mixing matrix U = Ue† Uν, Ue and Uν being the 3 × 3 unitary matrices resulting from the diagonalisation of the charged lepton and neutrino Majorana mass matrices, respectively. We focus on forms of Ue and Uν permitting to express α21 / 2 and α31 / 2 in terms of the Dirac phase δ and the three neutrino mixing angles of the standard parametrisation of U, and the angles and the two Majorana-like phases ξ21 / 2 and ξ31 / 2 present, in general, in Uν. The concrete forms of Uν considered are fixed by, or associated with, symmetries (tri-bimaximal, bimaximal, etc.), so that the angles in Uν are fixed. For each of these forms and forms of Ue that allow to reproduce the measured values of the three neutrino mixing angles θ12, θ23 and θ13, we derive predictions for phase differences (α21 / 2 -ξ21 / 2), (α31 / 2 -ξ31 / 2), etc., which are completely determined by the values of the mixing angles. We show that the requirement of generalised CP invariance of the neutrino Majorana mass term implies ξ21 = 0 or π and ξ31 = 0 or π. For these values of ξ21 and ξ31 and the best fit values of θ12, θ23 and θ13, we present predictions for the effective Majorana mass in neutrinoless double beta decay for both neutrino mass spectra with normal and inverted ordering.
International Nuclear Information System (INIS)
Gómez-Cadenas, J.J.; Martín-Albo, J.; Vidal, J. Muñoz; Peña-Garay, C.
2013-01-01
The South Pole Telescope (SPT) has probed an expanded angular range of the CMB temperature power spectrum. Their recent analysis of the latest cosmological data prefers nonzero neutrino masses, with Σm ν = (0.32±0.11) eV. This result, if confirmed by the upcoming Planck data, has deep implications on the discovery of the nature of neutrinos. In particular, the values of the effective neutrino mass m ββ involved in neutrinoless double beta decay (ββ0ν) are severely constrained for both the direct and inverse hierarchy, making a discovery much more likely. In this paper, we focus in xenon-based ββ0ν experiments, on the double grounds of their good performance and the suitability of the technology to large-mass scaling. We show that the current generation, with effective masses in the range of 100 kg and conceivable exposures in the range of 500 kg·year, could already have a sizeable opportunity to observe ββ0ν events, and their combined discovery potential is quite large. The next generation, with an exposure in the range of 10 ton·year, would have a much more enhanced sensitivity, in particular due to the very low specific background that all the xenon technologies (liquid xenon, high-pressure xenon and xenon dissolved in liquid scintillator) can achieve. In addition, a high-pressure xenon gas TPC also features superb energy resolution. We show that such detector can fully explore the range of allowed effective Majorana masses, thus making a discovery very likely
Search for double beta decay processes of {sup 124}Xe with XENON100 and XENON1T
Energy Technology Data Exchange (ETDEWEB)
Fieguth, Alexander [IKP, Westfaelische-Wilhelms-Universitaet Muenster (Germany)
2016-07-01
Driven by the search for dark matter particles the XENON dark matter project recently installed its next stage multi-ton experiment XENON1T at the LNGS, which will probe the spin-indpendent-WIMP-Nucleon cross section down to 2.10{sup -47} cm{sup 2}. Besides its main purpose different particle physics topics can be addressed by the taken data. One example are the double beta decay processes of natural isotope {sup 124}Xe. This isotope is expected to decay via two-neutrino double electron capture (2νECEC) and due to its high Q-value of 2864 keV additionally through 2νβ{sup +}β{sup +}. Since these processes have not been detected so far, there is only a lower limit the respective half-life (e.g. > 4.7.10{sup 21} yr for 2νECEC). A detection of the 2νECEC is possible using XENON1T data by looking for its clear signature of secondary X-rays or Auger electrons and at least new lower half-life limits for all other decay channels can be obtained. While these processes are expected from standard model physics, a detection of a decay without neutrinos (e.g 0νECEC) would hint towards beyond the standard model physics and could derive conclusions on the neutrino mass. Until XENON1T is taking data, the search for all processes can be tested in the recorded data of its predecessor XENON100.
Energy Technology Data Exchange (ETDEWEB)
Vala, L
2003-09-01
The NEMO3 detector was designed for the study of double beta decay and in particular to search for the neutrinoless double beta decay process (0{nu}{beta}{beta}). The intended sensitivity in terms of a half-life limit for the 0{nu}{beta}{beta} decay is of the order of 10{sup 25} y which corresponds to an effective neutrino mass m{sub {nu}} on the level of (0.3 - 0.1) eV. The 0{nu}{beta}{beta} process is today the most promising test of the Majorana nature of the neutrino. The detector was constructed in the Modane Underground Laboratory (LSM) in France by an international collaboration including France, Russia, the Czech Republic, the USA, the UK, Finland, and Japan. The experiment has been taking data since May 2002. The quantity of {sup 100}Mo in the detector (7 kg) allows an efficient measurement of the two-neutrino double beta decay (2{nu}{beta}{beta}) of {sup 100}Mo to the excited 0{sub 1}{sup +} state (eeN{gamma} channel). Monte-Carlo simulations of the effect and of all the relative sources of background have been produced in order to define a set of appropriate selection criteria. Both Monte-Carlo simulations and special runs with sources of {sup 208}Tl and {sup 214}Bi showed that the only significant background in the eeN{gamma} channel comes from radon that penetrated inside the wire chamber of NEMO3. The experimental data acquired from May 2002 to May 2003 have been analysed in order to determine the signal from the 2{nu}{beta}{beta} decay of {sup 100}Mo to the excited 0{sub 1}{sup +} state and the corresponding background level. The physical result, which was obtained at the level of four standard deviations, is given in the form of an interval of half-life values at 95% confidence level: [5.84*10{sup 20}, 2.26*10{sup 21}] y for method A and [5.83*10{sup 20}, 1.71*10{sup 21}] y for method B. (author)
Bound states and molecular structure of systems with hyperons
International Nuclear Information System (INIS)
Akaishi, Y.
1992-01-01
Microscopic calculations are done for Σ-hypernuclear few-body systems by a method named ATMS. Among two- to five-body systems, only the Σ 4 He(0 + ) and Σ 4 H(0 + ) hypernuclei are expected to be bound: The binding energy and the width of the former are calculated to be 3.7 ∼ 4.6 MeV and 4.5 ∼ 7.9 MeV, respectively. The observation of Σ 4 He at KEK is in good agreement with the above prediction. The nucleus-Σ potential has a strong Lane term and a repulsive bump at short distance. The Lane term makes the system bound and the bump suppresses the ΣN → ΛN conversion. X-ray measurement of level shifts in the 4 He-Σ - , 3 He-Σ - and 3 H-Σ - atoms can provide another information on the Lane term. In 208 Pb, there may exist a peculiar state, Coulomb-assisted (atomnucleus) hybrid state, where Σ - is trapped in the surface region by the strong interaction with the aid of the inner centrifugal repulsion and the outer Coulomb attraction. An analysis is given for new data of Ξ -.12 C atomic or nuclear systems from the emulsion-counter experiment at KEK. The double-Λ hypernucleus formation rate is calculated for a stopped Ξ - on 4 He. A high branching ratio of 37% is obtained for the ΛΛ 4 H formation from a Ξ -.4 He atom. The detection of about 2.3 MeV neutron is proposed to search for lightest double-Λ hypernucleus ΛΛ 4 H. (author)
Amplification of non-Markovian decay due to bound state absorption into continuum
International Nuclear Information System (INIS)
Garmon, S.; Simine, L.; Segal, D.; Petrosky, T.
2013-01-01
It is known that quantum systems yield non-exponential (power law) decay on long time scales, associated with continuum threshold effects contributing to the survival probability for a prepared initial state. For an open quantum system consisting of a discrete state coupled to continuum, we study the case in which a discrete bound state of the full Hamiltonian approaches the energy continuum as the system parameters are varied. We find in this case that at least two regions exist yielding qualitatively different power law decay behaviors; we term these the long time 'near zone' and long time 'far zone'. In the near zone the survival probability falls off according to a t -1 power law, and in the far zone i t falls off as t -3 . We show that the timescale T Q separating these two regions is inversely related to the gap between the discrete bound state energy and the continuum threshold. In the case that the bound state is absorbed into the continuum and vanishes, then the time scale T Q diverges and the survival probability follows the t -1 power law even on asymptotic scales. Conversely, one could study the case of an anti-bound state approaching the threshold before being ejected from the continuum to form a bound state. Again the t -1 power law dominates precisely at the point of ejection. (Copyright copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Application of the N-quantum approximation method to bound state problems
International Nuclear Information System (INIS)
Raychaudhuri, A.
1977-01-01
The N-quantum approximation (NQA) method is examined in the light of its application to bound state problems. Bound state wave functions are obtained as expansion coefficients in a truncated Haag expansion. From the equations of motion for the Heisenberg field and the NQA expansion, an equation satisfied by the wave function is derived. Two different bound state systems are considered. In one case, the bound state problem of two identical scalars by scalar exchange is analyzed using the NQA. An integral equation satisfied by the wave function is derived. In the nonrelativistic limit, the equation is shown to reduce to the Schroedinger equation. The equation is solved numerically, and the results compared with those obtained for this system by other methods. The NQA method is also applied to the bound state of two spin 1/2 particles with electromagnetic interaction. The integral equation for the wave function is shown to agree with the corresponding Bethe Salpeter equation in the nonrelativistic limit. Using the Dirac (4 x 4) matrices the wave function is expanded in terms of structure functions and the equation for the wave function is reduced to two disjoint sets of coupled equation for the structure functions
International Nuclear Information System (INIS)
Saito, T.Y.; Wu, Y.; Ishikawa, S.; Sasakawa, T.
1990-01-01
Triton β-decay has been calculated using wave functions for 3 He and 3 H obtained from (Coulomb-modified) Faddeev equations for various interactions. We get a value for the Gamow-Teller matrix element of √3 (0.962±0.002) without regards to two- or three-nucleon inteactions. This value agrees with the experimental value. (orig.)
Bound-state quark and gluon contributions to structure functions in QCD
International Nuclear Information System (INIS)
Brodsky, S.J.
1990-08-01
One can distinguish two types of contributions to the quark and gluon structure functions of hadrons in quantum chromodynamics: ''intrinsic'' contributions, which are due to the direct scattering on the bound-state constituents, and ''extrinsic'' contributions, which are derived from particles created in the collision. In this talk, I discussed several aspects of deep inelastic structure functions in which the bound-state structure of the proton plays a crucial role: the properties of the intrinsic gluon distribution associated with the proton bound-state wavefunction; the separation of the quark structure function of the proton onto intrinsic ''bound-valence'' and extrinsic ''non-valence'' components which takes into account the Pauli principle; the properties and identification of intrinsic heavy quark structure functions; and a theory of shadowing and anti-shadowing of nuclear structure functions, directly related to quark-nucleon interactions and the gluon saturation phenomenon. 49 refs., 5 figs
Bound-state quark and gluon contributions to structure functions in QCD
International Nuclear Information System (INIS)
Brodsky, S.J.
1991-01-01
One can distinguish two types of contributions to the quark and gluon structure functions of hadrons in quantum chromodynamics: 'intrinsic' contributions, which are due to the direct scattering on the bound-state constituents, and 'extrinsic' contributions, which are derived from particles created in the collision. In this talk, I discuss several aspects of deep inealstic structure functions in which the bound-state structure of the proton plays a crucial role: (1) the properties of the intrinsic gluon distribution associated with the proton bound-state wavefunction; (2) the separation of the quark structure function of the proton into intrinsic 'bound-valence' and extrinsic 'non-valence' components which takes into account the Pauli principle; (3) the properties and identification of intrinsic heavy quark structure functions; and (4) a theory of shadowing and anti-shadowing of nuclear structure functions, directly related to quark-nucleon interactions and the gluon saturation phenomenon. (orig.)
New approximation to the bound states of Schroedinger operators with coulomb interaction
International Nuclear Information System (INIS)
Nunez, M.A.; Izquierdo B., G.
1994-01-01
In this work, the authors present a mathematical formulation of the physical fact that the bound states of a quantum system confined into a box Ω (with impenetrable walls) are similar to those of the unconfined system, if the box Ω is sufficiently large, and it is shown how the bound states of atomic and molecular Hamiltonians can be approximated by those of the system confined for a box Ω large enough (Dirichlet eigenproblem in Ω). Thus, a method for computing bound states is obtained which has the advantage of reducing the problem to the case of compact operators. This implies that a broad class of numerical and analytic techniques used for solving the Dirichlet problem, may be applied in full strength to obtain accurate computations of energy levels, wave functions, and other physical properties of interest
Parra-Rivas, Pedro; Gomila, Damia; Colet, Pere; Gelens, Lendert
2017-07-01
Bound states, also called soliton molecules, can form as a result of the interaction between individual solitons. This interaction is mediated through the tails of each soliton that overlap with one another. When such soliton tails have spatial oscillations, locking or pinning between two solitons can occur at fixed distances related with the wavelength of these oscillations, thus forming a bound state. In this work, we study the formation and stability of various types of bound states in the Lugiato-Lefever equation by computing their interaction potential and by analyzing the properties of the oscillatory tails. Moreover, we study the effect of higher order dispersion and noise in the pump intensity on the dynamics of bound states. In doing so, we reveal that perturbations to the Lugiato-Lefever equation that maintain reversibility, such as fourth order dispersion, lead to bound states that tend to separate from one another in time when noise is added. This separation force is determined by the shape of the envelope of the interaction potential, as well as an additional Brownian ratchet effect. In systems with broken reversibility, such as third order dispersion, this ratchet effect continues to push solitons within a bound state apart. However, the force generated by the envelope of the potential is now such that it pushes the solitons towards each other, leading to a null net drift of the solitons. Contribution to the Topical Issue "Theory and Applications of the Lugiato-Lefever Equation", edited by Yanne K. Chembo, Damia Gomila, Mustapha Tlidi, Curtis R. Menyuk.
Large N Chern-Simons with massive fundamental fermions — A model with no bound states
International Nuclear Information System (INIS)
Frishman, Yitzhak; Sonnenschein, Jacob
2014-01-01
In a previous paper http://dx.doi.org/10.1007/JHEP12(2013)091, we analyzed the theory of massive fermions in the fundamental representation coupled to a U(N) Chern-Simons gauge theory in three dimensions at level K. It was done in the large N, large K limits where λ=(N/K) was kept fixed. Among other results, we showed there that there are no high mass “quark anti-quark" bound states. Here we show that there are no bound states at all.
Scattering integral equations and four nucleon problem. Four nucleon bound states and scattering
International Nuclear Information System (INIS)
Narodetskij, I.M.
1981-01-01
Existing results from the application of integral equation technique four-nucleon bound states and scattering are reviewed. The purpose of this review is to provide a clear and elementary introduction in the integral equation method and to demonstrate its usefulness in physical applications. Developments in the actual numerical solutions of Faddeev-Yakubovsky type equations are such that a detailed comparison can be made with experiment. Bound state calculations indicate that a nonrelativistic description with pairwise nuclear forces does not suffice and additional degrees of freedom are noted [ru
Symanzik approach in modeling of bound states of Dirac particle in singular background
Directory of Open Access Journals (Sweden)
Pismak Yu. M.
2017-01-01
Full Text Available In the model of interaction of spinor field with homogeneous isotropic material plane constructed in framework of Symanzik approach, the bound states are studied. For localized near plane Dirac particle the expression for current, charge and density are presented. For bound state with massless dispersion law the current, charge and density are calculated for simplified model with 2 parameter exactly.The model can find application to a wide class of phenomena arising by the interaction of fields of quantum electrodynamics with two-dimensional materials.
Heavy-to-light form factors for non-relativistic bound states
International Nuclear Information System (INIS)
Bell, G.; Feldmann, Th.
2007-01-01
We investigate transition form factors between non-relativistic QCD bound states at large recoil energy. Assuming the decaying quark to be much heavier than its decay product, the relativistic dynamics can be treated according to the factorization formula for heavy-to-light form factors obtained from the heavy-quark expansion in QCD. The non-relativistic expansion determines the bound-state wave functions to be Coulomb-like. As a consequence, one can explicitly calculate the so-called 'soft-overlap' contribution to the transition form factor
Bound states in the (2+1)D scalar electrodynamics with Chern-Simons term
International Nuclear Information System (INIS)
Gomes, M.O.C.; Malacarne, L.C.
1994-01-01
This work studies the existence of bound states for the 3-dimensions scalar electrodynamics, with the Chern-Simons. Quantum field theory is used for calculation of the M fi scattering matrices, in the non-relativistic approximation. The field propagators responsible for the interaction in the scattering processes have been calculated, and scattering matrices have been constructed. After obtaining the scattering matrix, the cross section in the quantum field theory has been compared with the quantum mechanic cross section in the Born approximation, allowing to obtain the form of the potential responsible for the interactions in the scattering processes. The possibility of bound states are analyzed by using the Schroedinger equation
Tunneling spectroscopy of quasiparticle bound states in a spinful Josephson junction.
Chang, W; Manucharyan, V E; Jespersen, T S; Nygård, J; Marcus, C M
2013-05-24
The spectrum of a segment of InAs nanowire, confined between two superconducting leads, was measured as function of gate voltage and superconducting phase difference using a third normal-metal tunnel probe. Subgap resonances for odd electron occupancy-interpreted as bound states involving a confined electron and a quasiparticle from the superconducting leads, reminiscent of Yu-Shiba-Rusinov states-evolve into Kondo-related resonances at higher magnetic fields. An additional zero-bias peak of unknown origin is observed to coexist with the quasiparticle bound states.
International Nuclear Information System (INIS)
Etienvre, A.I.
2003-04-01
The NEMO3 detector, installed in the Frejus Underground Laboratory, is dedicated to the study of neutrinoless double beta decay: the observation of this process would sign the massive and Majorana nature of neutrino. The experiment consists in very thin central source foils (the total mass is equal to 10 kg), a tracking detector made of drift cells operating in Geiger mode, a calorimeter made of plastic scintillators associated to photomultipliers, a coil producing a 30 gauss magnetic field and two shields, dedicated to the reduction of the γ-ray and neutron fluxes. In the first part, I describe the implications of several mechanisms, related to trilinear R-parity violation, on double beta decay. The second part is dedicated to a detailed study of the tracking detector of the experiment: after a description of the different working tests, I present the determination of the characteristics of the tracking reconstruction (transverse and longitudinal resolution, by Geiger cell and precision on vertex determination, charge recognition). The last part corresponds to the analysis of the data taken by the experiment. On the one hand, an upper limit on the Tl 208 activity of the sources has been determined: it is lower than 68 mBq/kg, at 90% of confidence level. On the other hand, I have developed and tested on these data a method in order to analyse the neutrinoless double beta decay signal; this method is based on a maximum of likelihood using all the available information. Using this method, I could determine a first and very preliminary upper limit on the effective mass of the neutrino. (author)
Bound states of the Dirac equation with some physical potentials by the Nikiforov-Uvarov method
Energy Technology Data Exchange (ETDEWEB)
Setare, Mohammad R; Haidari, S [Department of Physics, University of Kurdistan, Pasdaran Avenue, Sanandaj (Iran, Islamic Republic of)], E-mail: rezakord@ipm.ir, E-mail: heidary.somayeh@gmail.com
2010-01-15
Exact analytical solutions for the s-wave Dirac equation with the reflectionless-type, Rosen-Morse and Manning-Rosen potentials are obtained, under the condition of spin symmetry. We obtained bound state energy eigenvalues and corresponding spinor wave function in the framework of the Nikiforov-Uvarov (NU) method.
Boson bound states in the β-Fermi–Pasta–Ulam model
Indian Academy of Sciences (India)
5. — journal of. November 2013 physics pp. 839–848. Boson bound states in the ... of Basic Sciences, The First Aeronautical Institute of the Air Force, Xinyang 464000, ..... [4] N Boechler, G Theocharis, S Job, P G Kevrekidis, M A Porter and C ...
Ultraheavy Yukawa-bound states of fourth-generation at Large ...
Indian Academy of Sciences (India)
2012-10-05
Oct 5, 2012 ... Abstract. A study of bound states of the fourth-generation quarks in the range of 500–700 GeV is presented, where the binding energies are expected to be mainly of Yukawa origin, with QCD subdominant. Near degeneracy of their masses exhibits a new 'isospin'. The production of a colour- octet, isosinglet ...
Orthogonality-condition model for bound states with a separable expansion of the potential
International Nuclear Information System (INIS)
Pal, K.F.
1984-01-01
A very efficient solution of the equation of Saito's orthogonality-condition model (OCM) is reported for bound states by means of a separable expansion of the potential (PSE method). Some simplifications of the published formulae of the PSE method is derived, which facilitate its application to the OCM and may be useful in solving the Schroedinger equation as well. (author)
The hyperbolic step potential: Anti-bound states, SUSY partners and Wigner time delays
Energy Technology Data Exchange (ETDEWEB)
Gadella, M. [Departamento de Física Teórica, Atómica y Óptica and IMUVA, Universidad de Valladolid, E-47011 Valladolid (Spain); Kuru, Ş. [Department of Physics, Faculty of Science, Ankara University, 06100 Ankara (Turkey); Negro, J., E-mail: jnegro@fta.uva.es [Departamento de Física Teórica, Atómica y Óptica and IMUVA, Universidad de Valladolid, E-47011 Valladolid (Spain)
2017-04-15
We study the scattering produced by a one dimensional hyperbolic step potential, which is exactly solvable and shows an unusual interest because of its asymmetric character. The analytic continuation of the scattering matrix in the momentum representation has a branch cut and an infinite number of simple poles on the negative imaginary axis which are related with the so called anti-bound states. This model does not show resonances. Using the wave functions of the anti-bound states, we obtain supersymmetric (SUSY) partners which are the series of Rosen–Morse II potentials. We have computed the Wigner reflection and transmission time delays for the hyperbolic step and such SUSY partners. Our results show that the more bound states a partner Hamiltonian has the smaller is the time delay. We also have evaluated time delays for the hyperbolic step potential in the classical case and have obtained striking similitudes with the quantum case. - Highlights: • The scattering matrix of hyperbolic step potential is studied. • The scattering matrix has a branch cut and an infinite number of poles. • The poles are associated to anti-bound states. • Susy partners using antibound states are computed. • Wigner time delays for the hyperbolic step and partner potentials are compared.
On the bound states of Schrodinger operators with -interactions on conical surfaces
Czech Academy of Sciences Publication Activity Database
Lotoreichik, Vladimir; Ourmieres-Bonafos, T.
2016-01-01
Roč. 41, č. 6 (2016), s. 999-1028 ISSN 0360-5302 Institutional support: RVO:61389005 Keywords : conical and hyperconical surfaces * delta-interaction * existence of bound states * Schrodinger operator * spectral asymptotics Subject RIV: BE - Theoretical Physics Impact factor: 1.608, year: 2016
Bound states in quantum field theory and coherent states: A fresh look
International Nuclear Information System (INIS)
Misra, S.P.
1986-09-01
We consider here bound state equations in quantum field theory where the state explicitly includes radiation quanta as constituents with the number of such quanta not fixed. The fully interacting system is dealt with through equal time commutators/anticommutators of field operators. The multiparticle channel for the radiation field is approximated through coherent state representations. (author)
Robustness of Majorana bound states in the short-junction limit
Sticlet, D.C.; Nijholt, B.; Akhmerov, A.R.
2017-01-01
We study the effects of strong coupling between a superconductor and a semiconductor nanowire on the creation of the Majorana bound states, when the quasiparticle dwell time in the normal part of the nanowire is much shorter than the inverse superconducting gap. This "short-junction" limit is
Another comment on 'relativistic description of quark-antiquark bound states'
International Nuclear Information System (INIS)
Lucha, W.; Rupprecht, H.; Schoeberl, F.F.
1991-04-01
We point out some ambiguities in the treatment of fermion-antifermion bound states by solving the reduced Salpeter equation in coordinate space. Our observations allow to cast some doubt on the validity of the conclusion of Gara et al. that moving from a nonrelativistic to a relativistic description makes things worse. (authors)