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Werner Rodejohann - One of the best experts on this subject based on the ideXlab platform.
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loop enhanced rate of neutrinoless double Beta Decay
Journal of High Energy Physics, 2019Co-Authors: Werner RodejohannAbstract:Neutrino masses can be generated radiatively. In such scenarios their masses are calculated by evaluating a self-energy diagram with vanishing external momentum, i.e. taking only the leading order term in a momentum expansion. The difference between the full self-energy and the mass is experimentally difficult to access, since one needs off-shell neutrinos to observe it. However, massive Majorana neutrinos that mediate neutrinoless double Beta Decay (0νββ) are off-shell, with the virtuality of order 100 MeV. If the energy scale of the self-energy loop is of the order of this virtuality, the amplitude of double Beta Decay can be modified by the unsuppressed loop effect. This can have a drastic impact on the interpretation of future observations or limits of the 0νββ Decay.
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effective neutrino masses in katrin and future tritium Beta Decay experiments
arXiv: High Energy Physics - Phenomenology, 2019Co-Authors: Guoyuan Huang, Werner Rodejohann, Shun ZhouAbstract:Past and current direct neutrino mass experiments set limits on the so-called effective neutrino mass, which is an incoherent sum of neutrino masses and lepton mixing matrix elements. A classical form of the electron energy spectrum is often assumed. Alternative definitions of effective masses exist, and an exact relativistic spectrum is calculable. We quantitatively compare the validity of those different approximations as function of energy resolution and exposure in view of tritium Beta Decays in the KATRIN, Project 8 and PTOLEMY experiments. Furthermore, adopting the Bayesian approach, we present the posterior distributions of the effective neutrino masses by including current experimental information from neutrino oscillations, Beta Decay, neutrinoless double-Beta Decay and cosmological observations. Both linear and logarithmic priors for the smallest neutrino mass are assumed.
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loop enhanced rate of neutrinoless double Beta Decay
arXiv: High Energy Physics - Phenomenology, 2019Co-Authors: Werner RodejohannAbstract:Neutrino masses can be generated radiatively. In such scenarios their masses are calculated by evaluating a self-energy diagram with vanishing external momentum, i.e. taking only the leading order term in a momentum expansion. The difference between the full self-energy and the mass is experimentally difficult to access, since one needs off-shell neurinos to observe them. However, massive Majorana neutrinos that mediate neutrinoless double Beta Decay ($0\nu\Beta\Beta$) are off-shell, with the virtuality of order 100 MeV. If the energy scale of the self-energy loop is of the order of this virtuality, the amplitude of double Beta Decay can be modified by the unsuppressed loop effect. This can have a drastic impact on the interpretation of future observations of the $0\nu\Beta\Beta$ Decay.
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neutrinoless double Beta Decay status and prospects
Annual Review of Nuclear and Particle Science, 2019Co-Authors: M J Dolinski, A W P Poon, Werner RodejohannAbstract:Neutrinoless double-Beta Decay is a forbidden, lepton-number-violating nuclear transition whose observation would have fundamental implications for neutrino physics, theories beyond the Standard Mo...
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neutrinoless double Beta Decay status and prospects
arXiv: Nuclear Experiment, 2019Co-Authors: M J Dolinski, A W P Poon, Werner RodejohannAbstract:Neutrinoless double-Beta Decay is a forbidden, lepton-number-violating nuclear transition whose observation would have fundamental implications for neutrino physics, theories beyond the Standard Model and cosmology. In this review, we summarize the theoretical progress to understand this process, the expectations and implications under various particle physics models, as well as the nuclear physics challenges that affect the precise predictions of the Decay half-life. We will also provide a synopsis of the current and future large-scale experiments that aim at discovering this process in physically well-motivated half-life ranges.
Amand Faessler - One of the best experts on this subject based on the ideXlab platform.
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nuclear matrix elements for neutrinoless double Beta Decay and double electron capture
arXiv: Nuclear Theory, 2012Co-Authors: Amand Faessler, Vadim Rodin, F SimkovicAbstract:A new generation of neutrinoless double Beta Decay experiments with improved sensitivity is currently under design and construction. They will probe inverted hierarchy region of the neutrino mass pattern. There is also a revived interest to the resonant neutrinoless double-electron capture, which has also a potential to probe lepton number conservation and to investigate the neutrino nature and mass scale. The primary concern are the nuclear matrix elements. Clearly, the accuracy of the determination of the effective Majorana neutrino mass from the measured 0\nu\Beta\Beta-Decay half-life is mainly determined by our knowledge of the nuclear matrix elements. We review recent progress achieved in the calculation of 0\nu\Beta\Beta and 0\nu ECEC nuclear matrix elements within the quasiparticle random phase approximation. A considered self-consistent approach allow to derive the pairing, residual interactions and the two-nucleon short-range correlations from the same modern realistic nucleon-nucleon potentials. The effect of nuclear deformation is taken into account. A possibility to evaluate 0\nu\Beta\Beta-Decay matrix elements phenomenologically is discussed.
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assessment of uncertainties in qrpa 0 nu Beta Beta Decay nuclear matrix elements
arXiv: Nuclear Theory, 2005Co-Authors: V A Rodin, Amand Faessler, F Simkovic, P VogelAbstract:The nuclear matrix elements $M^{0\nu}$ of the neutrinoless double Beta Decay ($0\nu\Beta\Beta$) of most nuclei with known $2\nu\Beta\Beta$-Decay rates are systematically evaluated using the Quasiparticle Random Phase Approximation (QRPA) and Renormalized QRPA (RQRPA). The experimental $2\nu\Beta\Beta$-Decay rate is used to adjust the most relevant parameter, the strength of the particle-particle interaction. New results confirm that with such procedure the $M^{0\nu}$ values become essentially independent on the size of the single-particle basis. Furthermore, the matrix elements are shown to be also rather stable with respect to the possible quenching of the axial vector strength parametrized by reducing the coupling constant $g_A$, as well as to the uncertainties of parameters describing the short range nucleon correlations. Theoretical arguments in favor of the adopted way of determining the interaction parameters are presented. Furthermore, a discussion of other implicit and explicit parameters, inherent to the QRPA method, is presented. Comparison is made of the ways these factors are chosen by different authors. It is suggested that most of the spread among the published $0\nu\Beta\Beta$ Decay nuclear matrix elements can be ascribed to these choices.
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the pauli principle qrpa and the two neutrino double Beta Decay
Nuclear Physics, 1996Co-Authors: J Schwieger, Fedor Simkovic, Amand FaesslerAbstract:Abstract We examine the violation of the Pauli exclusion principle in the Quasiparticle Random Phase Approximation (QRPA) calculation of the two-neutrino double Beta Decay matrix elements, which has its origin in the quasi-boson approximation. For that purpose we propose a new renormalized QRPA with proton-neutron pairing method (full-RQRPA) for nuclear-structure studies, which includes ground-state correlation beyond the QRPA. This is achieved by using the renormalized quasi-boson approximation, in which the Pauli exclusion principle is taken into account more carefully. The full-RQRPA has been applied to two-neutrino double Beta Decay of 76 Ge, 82 Se, 128 Te and 130 Te. The nuclear matrix elements have been found significantly less sensitive to the increasing strength of particle-particle interaction in the physically interesting region in comparison with QRPA results. The strong differences between the results of both methods indicate that the Pauli exclusion principle plays an important role in the evaluation of the double Beta Decay. The inclusion of the Pauli principle removes the difficulties with the strong dependence on the particle-particle strength g pp in the QRPA on the two-neutrino double Beta Decay.
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the pauli principle qrpa and the two neutrino double Beta Decay
arXiv: Nuclear Theory, 1996Co-Authors: J Schwieger, Fedor Simkovic, Amand FaesslerAbstract:We examine the violation of the Pauli exclusion principle in the Quasiparticle Random Phase Approximation (QRPA) calculation of the two-neutrino double Beta Decay matrix elements, which has its origin in the quasi-boson approximation. For that purpose we propose a new renormalized QRPA with proton-neutron pairing method (full-RQRPA) for nuclear structure studies, which includes ground state correlation beyond the QRPA. This is achieved by using of renormalized quasi-boson approximation, in which the Pauli exclusion principle is taken into account more carefully. The full-RQRPA has been applied to two-neutrino double Beta Decay of $^{76}Ge$, $^{82}Se$, $^{128}Te$ and $^{130}Te$. The nuclear matrix elements have been found significantly less sensitive to the increasing strength of particle-particle interaction in the physically interesting region in comparison with QRPA results. The strong differences between the results of both methods indicate that the Pauli exclusion principle plays an important role in the evaluation of the double Beta Decay. The inclusion of the Pauli principle removes the difficulties with the strong dependence on the particle-particle strength $g_{pp}$ in the QRPA on the two-neutrino double Beta Decay.
F Simkovic - One of the best experts on this subject based on the ideXlab platform.
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neutrinoless double Beta Decay and neutrino mass
arXiv: High Energy Physics - Phenomenology, 2016Co-Authors: J D Vergados, F Simkovic, H EjiriAbstract:The observation of neutrinoless double Beta Decay will have important consequences. First it will signal that lepton number is not conserved and the neutrinos are Majorana particles. Second, it represents our best hope for determining the absolute neutrino mass scale at the level of a few tens of meV. To achieve the last goal, however, certain hurdles have to be overcome involving particle, nuclear and experimental physics. Particle physics is important since it provides the mechanisms for neutrinoless double Beta Decay. In this review we emphasize the light neutrino mass mechanism. 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 recently developed sophisticated nuclear structure approaches, employing different methods and techniques of calculation. We also examine the question of quenching of the axial vector coupling constant, which may have important consequences on the size of the nuclear matrix elements. From an experimental point of view it is challenging, since the life times are extremely long and one has to fight against formidable backgrounds. One needs large isotopically enriched sources and detectors with good energy resolution and very low background.
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nuclear matrix elements for neutrinoless double Beta Decay and double electron capture
arXiv: Nuclear Theory, 2012Co-Authors: Amand Faessler, Vadim Rodin, F SimkovicAbstract:A new generation of neutrinoless double Beta Decay experiments with improved sensitivity is currently under design and construction. They will probe inverted hierarchy region of the neutrino mass pattern. There is also a revived interest to the resonant neutrinoless double-electron capture, which has also a potential to probe lepton number conservation and to investigate the neutrino nature and mass scale. The primary concern are the nuclear matrix elements. Clearly, the accuracy of the determination of the effective Majorana neutrino mass from the measured 0\nu\Beta\Beta-Decay half-life is mainly determined by our knowledge of the nuclear matrix elements. We review recent progress achieved in the calculation of 0\nu\Beta\Beta and 0\nu ECEC nuclear matrix elements within the quasiparticle random phase approximation. A considered self-consistent approach allow to derive the pairing, residual interactions and the two-nucleon short-range correlations from the same modern realistic nucleon-nucleon potentials. The effect of nuclear deformation is taken into account. A possibility to evaluate 0\nu\Beta\Beta-Decay matrix elements phenomenologically is discussed.
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assessment of uncertainties in qrpa 0 nu Beta Beta Decay nuclear matrix elements
arXiv: Nuclear Theory, 2005Co-Authors: V A Rodin, Amand Faessler, F Simkovic, P VogelAbstract:The nuclear matrix elements $M^{0\nu}$ of the neutrinoless double Beta Decay ($0\nu\Beta\Beta$) of most nuclei with known $2\nu\Beta\Beta$-Decay rates are systematically evaluated using the Quasiparticle Random Phase Approximation (QRPA) and Renormalized QRPA (RQRPA). The experimental $2\nu\Beta\Beta$-Decay rate is used to adjust the most relevant parameter, the strength of the particle-particle interaction. New results confirm that with such procedure the $M^{0\nu}$ values become essentially independent on the size of the single-particle basis. Furthermore, the matrix elements are shown to be also rather stable with respect to the possible quenching of the axial vector strength parametrized by reducing the coupling constant $g_A$, as well as to the uncertainties of parameters describing the short range nucleon correlations. Theoretical arguments in favor of the adopted way of determining the interaction parameters are presented. Furthermore, a discussion of other implicit and explicit parameters, inherent to the QRPA method, is presented. Comparison is made of the ways these factors are chosen by different authors. It is suggested that most of the spread among the published $0\nu\Beta\Beta$ Decay nuclear matrix elements can be ascribed to these choices.
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grand unified theory constrained supersymmetry and neutrinoless double Beta Decay
Physical Review D, 1999Co-Authors: Andrzej Wodecki, Wieslaw A Kaminski, F SimkovicAbstract:We analyze the contributions to the neutrinoless double $\Beta$ Decay ($0\nu\Beta\Beta$-Decay) coming from the Grand Unified Theory (GUT) constrained Minimal Supersymmetric Standard Model (MSSM) with trilinear R-parity breaking. We discuss the importance of two-nucleon and pion-exchange realizations of the quark-level $0\nu\Beta\Beta$-Decay transitions. In this context, the questions of reliability of the calculated relevant nuclear matrix elements within the Renormalized Quasiparticle Random Phase Approximation (pn-RQRPA) for several medium and heavy open-shell nuclei are addressed. The importance of gluino and neutralino contributions to $0\nu\Beta\Beta$-Decay is also analyzed. We review the present experiments and deduce limits on the trilinear R-parity breaking parameter $\lambda_{111}'$ from the non-observability of $0\nu\Beta\Beta$-Decay for different GUT constrained SUSY scenarios. In addition, a detailed study of limits on the MSSM parameter space coming from the $B \to X_s \gamma$ processes by using the recent CLEO and OPAL results is performed. Some studies in respect to the future $0\nu\Beta\Beta$-Decay project GENIUS are also presented.
H V Klapdorkleingrothaus - One of the best experts on this subject based on the ideXlab platform.
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evidence for neutrinoless double Beta Decay
arXiv: High Energy Physics - Phenomenology, 2002Co-Authors: H V Klapdorkleingrothaus, A. Dietz, H L Harney, I. V. KrivosheinaAbstract:The data of the Heidelberg-Moscow double Beta Decay experiment for the measuring period August 1990 - May 2000 (54.9813 kg y or 723.44 molyears), published recently, are analyzed using the potential of the Bayesian method for low counting rates. First evidence for neutrinoless double Beta Decay is observed giving first evidence for lepton number violation. The evidence for this Decay mode is 97% (2.2\sigma) with the Bayesian method, and 99.8% c.l. (3.1\sigma) with the method recommended by the Particle Data Group. The half-life of the process is found with the Bayesian method to be T_{1/2}^{0\nu} = (0.8 - 18.3) x 10^{25} y (95% c.l.) with a best value of 1.5 x 10^{25} y. The deduced value of the effective neutrino mass is, with the nuclear matrix elements from [Sta90,Tom91] = (0.11 - 0.56) eV (95% c.l.), with a best value of 0.39 eV. Uncertainties in the nuclear matrix elements may widen the range given for the effective neutrino mass by at most a factor 2. Our observation which at the same time means evidence that the neutrino is a Majorana particle, will be of fundamental importance for neutrino physics. PACS. 14.69.Pq Neutrino mass and mixing; 23.40.Bw Weak-interaction and lepton (including neutrino) aspects 23.40.-s Beta Decay; double Beta Decay; electron and muon capture.
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evidence for neutrinoless double Beta Decay
Modern Physics Letters A, 2001Co-Authors: H V Klapdorkleingrothaus, A. Dietz, H L Harney, I. V. KrivosheinaAbstract:The data of the Heidelberg–Moscow double Beta Decay experiment for the measuring period August 1990–May 2000 (54.9813 kg y or 723.44 molyears), published recently, are analyzed using the potential of the Bayesian method for low counting rates. First evidence for neutrinoless double Beta Decay is observed giving first evidence for lepton number violation. The evidence for this Decay mode is 97% (2.2σ) with the Bayesian method, and 99.8% c.l. (3.1σ) with the method recommended by the Particle Data Group. The half-life of the process is found with the Bayesian method to be $T_{1/2}^{0\nu} = (0.8\hbox{--}18.3)\times 10^{25}~{\rm y}$ (95% c.l.) with a best value of 1.5 × 1025y. The deduced value of the effective neutrino mass is, with the nuclear matrix elements from Ref. 1, = (0.11–0.56) eV (95% c.l.), with a best value of 0.39 eV. Uncertainties in the nuclear matrix elements may widen the range given for the effective neutrino mass by at most a factor 2. Our observation which at the same time means evide...
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seventy years of double Beta Decay from nuclear physics to beyond standard model particle physics
2001Co-Authors: H V KlapdorkleingrothausAbstract:Nuclear double Beta Decay is one of the most promising tools for probing beyond-the-standard-model physics on beyond-accelerator energy scales. It is already now probing the TeV scale, on which new physics should manifest itself according to theoretical expectations. Only in the early 1980s was it known that double Beta Decay yields information on the Majorana mass of the exchanged neutrino. At present, the sharpest bound for the electron neutrino mass arises from this process. It is only in the last 10 years that the much more far-reaching potential of double Beta Decay has been discovered. Today, the potential of double Beta Decay includes a broad range of topics that are equally relevant to particle physics and astrophysics, such as masses of heavy neutrinos, of sneutrinos, as SUSY models, compositeness, leptoquarks, left-right symmetric models, and tests of Lorentz symmetry and equivalence principle in the neutrino sector. Double Beta Decay has become indispensable nowadays for solving the problem of the neutrino mass spectrum and the structure of the neutrino mass matrix - together with present and future solar and atmospheric neutrino oscillation experiments. Some future double Beta experiments (like Genius) will be capable to be simultaneously neutrino observatories for double Beta Decay and low-energy solar neutrinos, and observatories for cold dark matter of ultimate sensitivity. This invaluable book outlines the development of double Beta research from its beginnings until its most recent achievements, and also presents the outlook for its highly exciting future.
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latest results from the heidelberg moscow double Beta Decay experiment
arXiv: High Energy Physics - Phenomenology, 2001Co-Authors: H V Klapdorkleingrothaus, A. Dietz, I. V. Krivosheina, L Baudis, G Heusser, S Kolb, B Majorovits, H Paes, H Strecker, V AlexeevAbstract:New results for the double Beta Decay of 76Ge are presented. They are extracted from Data obtained with the HEIDELBERG-MOSCOW, which operates five enriched 76Ge detectors in an extreme low-level environment in the GRAN SASSO. The two neutrino accompanied double Beta Decay is evaluated for the first time for all five detectors with a statistical significance of 47.7 kg y resulting in a half life of (T_(1/2))^(2nu) = [1.55 +- 0.01 (stat) (+0.19) (-0.15) (syst)] x 10^(21) years. The lower limit on the half-life of the 0nu Beta-Beta Decay obtained with pulse shape analysis is (T_(1/2))^(0_nu) > 1.9 x 10^(25) [3.1 x 10^(25)] years with 90% C.L. (68% C.L.) (with 35.5 kg y). This results in an upper limit of the effective Majorana neutrino mass of 0.35 eV (0.27 eV). No evidence for a Majoron emitting Decay mode or for the neutrinoless mode is observed.
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latest results from the heidelberg moscow double Beta Decay experiment
European Physical Journal A, 2001Co-Authors: H V Klapdorkleingrothaus, A. Dietz, I. V. Krivosheina, L Baudis, G Heusser, B Majorovits, H Paes, H Strecker, V Alexeev, A BalyshAbstract:New results for the double Beta Decay of 76Ge are presented. They are extracted from data obtained with the HEIDELBERG-MOSCOW experiment, which operates five enriched 76Ge detectors in an extreme low-level environment in the Gran Sasso underground laboratory. The two-neutrino-accompanied double Beta Decay is evaluated for the first time for all five detectors with a statistical significance of 47.7 kg y resulting in a half-life of T1/22ν = [1.55±0.01(stat)+0.19-0.15(syst)]×1021 y. The lower limit on the half-life of the 0νββ Decay obtained with pulse shape analysis is T1/20ν > 1.9×1025(3.1×1025) y with 90% C.L. (68% C.L.) (with 35.5 kg y). This results in an upper limit of the effective Majorana-neutrino mass of 0.35 eV (0.27 eV) using the matrix elements of A. Staudt et al.'s work (Europhys. Lett. 13, 31 (1990)). This is the most stringent limit at present from double Beta Decay. No evidence for a majoron-emitting Decay mode is observed.
S Baesler - One of the best experts on this subject based on the ideXlab platform.
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the nab experiment a precision measurement of unpolarized neutron Beta Decay
EPJ Web of Conferences, 2019Co-Authors: J Fry, S Baesler, Ricardo Alarcon, S Balascuta, Barron L Palos, T L Bailey, K Bass, N Birge, A BloseAbstract:Neutron Beta Decay is one of the most fundamental processes in nuclear physics and provides sensitive means to uncover the details of the weak interaction. Neutron Beta Decay can evaluate the ratio of axial-vector to vector coupling constants in the standard model, λ = g A /g V , through multiple Decay correlations. The Nab experiment will carry out measurements of the electron-neutrino correlation parameter a with a precision of δa /a = 10−3 and the Fierz interference term b to δb = 3 × 10−3 in unpolarized free neutron Beta Decay. These results, along with a more precise measurement of the neutron lifetime, aim to deliver an independent determination of the ratio λ with a precision of δλ/λ = 0.03% that will allow an evaluation of V ud and sensitively test CKM unitarity, independent of nuclear models. Nab utilizes a novel, long asymmetric spectrometer that guides the Decay electron and proton to two large area silicon detectors in order to precisely determine the electron energy and an estimation of the proton momentum from the proton time of flight. The Nab spectrometer is being commissioned at the Fundamental Neutron Physics Beamline at the Spallation Neutron Source at Oak Ridge National Lab. We present an overview of the Nab experiment and recent updates on the spectrometer, analysis, and systematic effects.
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new precision measurements of free neutron Beta Decay with cold neutrons
Journal of Physics G, 2014Co-Authors: S Baesler, J D Bowman, S I Penttila, D PocanicAbstract:Precision measurements in free neutron Beta Decay serve to determine the coupling constants of Beta Decay, and offer several stringent tests of the standard model. This study describes the free neutron Beta Decay program planned for the Fundamental Physics Beamline at the Spallation Neutron Source at Oak Ridge National Laboratory, and finally puts it into the context of other recent and planned measurements of neutron Beta Decay observables.
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new precision measurements of free neutron Beta Decay with cold neutrons
arXiv: Nuclear Experiment, 2014Co-Authors: S Baesler, J D Bowman, S I Penttila, D PocanicAbstract:Precision measurements in free neutron Beta Decay serve to determine the coupling constants of Beta Decay, and offer several stringent tests of the Standard Model. This paper describes the free neutron Beta Decay program planned for the Fundamental Physics Beamline at the Spallation Neutron Source at Oak Ridge National Laboratory, and puts it into the context of other recent and planned measurements of neutron Beta Decay observables.
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neutron Beta Decay studies with nab
11TH CONFERENCE ON THE INTERSECTIONS OF PARTICLE AND NUCLEAR PHYSICS: (CIPANP 2012), 2013Co-Authors: S Baesler, Ricardo Alarcon, L P Alonzi, S Balascuta, L Barronpalos, J D Bowman, M Bychkov, J Byrne, J R CalarcoAbstract:Precision measurements in neutron Beta Decay serve to determine the coupling constants of Beta Decay and allow for several stringent tests of the standard model. This paper discusses the design and the expected performance of the Nab spectrometer.