共查询到20条相似文献,搜索用时 15 毫秒
1.
A. S. Barabash 《Physics of Particles and Nuclei》2011,42(4):613-627
The present status of double beta decay experiments is reviewed. The results of the most sensitive experiments are discussed.
Proposals for future double beta decay experiments with a sensitivity to the 〈m
ν〉 at the level of (0.01–0.1) eV are considered. 相似文献
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V. D. Ashitkov A. S. Barabash S. G. Belogurov G. Carugno S. I. Konovalov F. Massera G. Puglierin R. R. Saakyan V. N. Stekhanov V. I. Umatov 《JETP Letters》2001,74(11):529-531
Two-neutrino double beta decay of 100Mo with half-life T 1/2=[7.2±0.9(stat)± 1.8(syst)]×1018 yr was detected using a liquid argon ionization chamber. With a C.L. of 68% (90%), the bounds on neutrinoless decay and decay with majoron emission were found to be 8.4(4.9)×1021 and 4.1(3.2)×1020 yr, respectively. An analysis of all available results provides the average “world” value T 1/2=(8.0±0.7)×1018 yr for the two-neutrino decay of 100Mo, and the corresponding nuclear matrix element is M GT=0.118±0.005. 相似文献
3.
David Bailin 《Contemporary Physics》2013,54(5):475-478
This review illustrates the present state of knowledge and directions of interest in infrared spectroscopy through the discussion of a number of examples of recent work. After a brief introduction the survey falls into three parts. The first is concerned with problems of assignment and interpretation of the spectra of polyatomic molecules, and the calculation of force constants. The second deals with the study of some chemical systems by infrared methods, and in the final section mention is made of a number of specialized topics such as matrix-isolation techniques. 相似文献
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《Nuclear Physics A》1999,658(4):299-312
After 10357 h of running the NEMO-2 tracking detector with an isotopically enriched zirconium source (0.084 mol yr of 96Zr), a ββ2ν decay half-life of T1/2=(2.1+0.8(stat)−0.4(stat)±0.2(syst))·1019 y was measured. Limits with a 90% C.L. on the 96Zr half-lives of 1.0·1021 y for ββ0ν decay to the ground state, 3.9·1020 y to the 2+ excited state and 3.5·1020 y for ββ0νχ0 decay with a Majoron (χ0) were obtained. The data also provide direct limits at the 90% C.L. for the 94Zr half-lives. These limits are 1.1·1017 y for ββ2ν decay to the ground state, 1.9·1019 y for ββ0ν decay to the ground state and 2.3·1018 y for ββ0νχ0 decay to ground state. 相似文献
6.
J. Bernabeu B. Desplanques J. Navarro S. Noguera 《Zeitschrift fur Physik C Particles and Fields》1990,46(2):323-328
The amplitude for ββ decay with 2ν emission is shown to be related to (p,n) and (n,p) reactions on the initial and final states, respectively. The suppression of both ββ and (n,p) reaction is connected, and its origin is discussed by referring to theSU(4) symmetry. From present data on the first ones, we estimate the forward (n, p) strength of relevance for the ββ problem. The interest of the experimental determination of this strength is emphasized. Assuming a perturbative breaking of theSU(4) symmetry, results are given for76Ge,82Se,128Te and130Te. 相似文献
7.
Fedor Šimkovic 《Progress in Particle and Nuclear Physics》2010,64(2):219-361
A brief review of recent progress in the field of double beta decay is presented. Different aspects from particle, nuclear and atomic physics of both two-neutrino (2νββ) and neutrinoless (0νββ) modes of the double β decay are discussed. It is argued that the R-parity violating supersymmetry (SUSY) contributes to the 0νββ-decay predominantly via charged pion-exchange between decaying nucleons. Further, a problem of reliable determination of the 0νββ-decay nuclear matrix elements (NMEs) is addressed. It is manifested that the uncertainty associated with the calculation of the 0νββ-decay NMEs can be diminished by suitably chosen nuclear probes. A new possibility for the study of lepton number non-conservation is proposed, namely oscillations plus deexcitations of neutral atoms. A phenomenological analysis of this process leads to a resonant enhancement of the neutrinoless double electron capture, that has a Breit-Wigner form. 相似文献
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The physics potential of neutrinoless double beta decay is discussed. Furthermore, experimental considerations as well as the current status of experiments are presented. Finally, an outlook towards the future, work on nuclear matrix elements and alternative processes is given. 相似文献
9.
Oliviero Cremonesi 《Hyperfine Interactions》2018,239(1):54
The observation of neutrinoless double beta decay would unambiguosly demonstrate that neutrinos are Majorana particles and would provide unique information about the ordering and absolute scale of neutrino masses. This very rare decay is actively searched for in a number of candidate isotopes. It violates lepton-number and is predicted by many extensions of the standard model. The most recent experimental results are reviewed. The technological advances and the most compelling requirements for the new generation of experiments are discussed. 相似文献
10.
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. 相似文献
11.
The spectrum of the bremsstrahlung due to the complete slowing down in aluminium of beta particles belonging to the continuous spectrum, was calculated for an arrangement, in which the beta emitter is completely enclosed in an absorber. The Bethe-Heitler cross-section, corrected by an empirical factor, was used. A table is given which makes it possible to calculate bremsstrahlung spectra of beta emitters with their maximal energy between 0·6 MeV and 2·0 MeV; the necessary additional calculations are quite simple. The error in the calculation is practically determined by the uncertainty in the determination of the cross-section and is equal to about 10%.
-
, - , , - . -, . , -, 0,6 –2,0 . . 10%.相似文献
12.
Ya. Nikitenko 《Physics of Particles and Nuclei》2016,47(6):1009-1013
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. 相似文献
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Using the general connection between the upper limit on the neutrino mass and the upper limits on certain types of non-standard-model interactions that can generate loop corrections to the neutrino mass, we derive constraints on some non-standard-model d --> ue- nu interactions. When cast into limits on n --> pe- nu coupling constants, our results yield constraints on scalar and tensor weak interactions improved by more than an order of magnitude over the current experimental limits. When combined with the existing limits, our results yield absolute value(C(S)/C(V)) approximately < 5 x 10(-3), absolute value(C'(S)/C(V)) approximately < 5 x 10(-3), absolute value(C(T)/C(A)) approximately < 1.2 x 10(-2), and absolute value(C'(T)/C(A)) approximately < 1.2 x 10(-2). 相似文献
15.
Oscar Naviliat-Cuncic 《Hyperfine Interactions》2013,214(1-3):181-188
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 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. 相似文献
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M. Kavatsyuk L. Batist F. Becker A. Blazhev W. Brüchle J. Döring T. Faestermann M. Górska H. Grawe Z. Janas A. Jungclaus M. Karny O. Kavatsyuk R. Kirchner M. La Commara S. Mandal C. Mazzocchi I. Mukha S. Muralithar C. Plettner A. Płochocki E. Roeckl M. Romoli M. Schädel J. Żylicz 《The European Physical Journal A - Hadrons and Nuclei》2006,29(2):183-188
The β-decay of 105Sn was re-investigated at the ISOL facility of GSI Darmstadt by using a total absorption spectrometer. The experimental results
include the half-life and β-delayed proton branching ratio of 32.7(5)s and 1.1(4) . 10-4, respectively, and the contribution of electron capture to the 105Sn decay of 0.420(35). The Gamow-Teller strength distribution peaking at 3.6MeV was measured, yielding a summed Gamow-Teller
strength of 3.0(4). The latter data are discussed in comparison with shell-model predictions based on an empirical interaction. 相似文献
19.
J. D. Robertson W. B. Walters S. F. Faller C. A. Stone R. L. Gill A. Piotrowski 《Zeitschrift für Physik A Hadrons and Nuclei》1985,322(4):705-706
With the96Ru(58Ni,2pn) reaction we produced151Yb81 and studied its decay after online mass separation by γ-spectroscopic techniques. The decay populates the four positive parity single proton levels in the N=82 daughter nucleus151Tm and establishes Iπ=1/2+ for the so far unknown151Tm low spin isomer. Using BCS theory proton single particle energies for151Tm were extracted from the observed excitation energies. 相似文献
20.
A calculation of the Coulomb correction to the nuclear beta decay is presented, in the context of the elementary-particle treatment of Kim and Primakoff, making use of the low-energy approximants to nuclear form factors. 相似文献