scholarly journals Probing Majorana neutrinos with double-β decay

Science ◽  
2019 ◽  
Vol 365 (6460) ◽  
pp. 1445-1448 ◽  
Author(s):  
M. Agostini ◽  
A. M. Bakalyarov ◽  
M. Balata ◽  
I. Barabanov ◽  
L. Baudis ◽  
...  
Keyword(s):  
Half Life ◽  
Particle Physics ◽  
Liquid Argon ◽  
Majorana Neutrino ◽  
Majorana Fermions ◽  
Β Decay ◽  
Active Liquid ◽  
Majorana Neutrinos ◽  
Double Β Decay ◽  
Majorana Neutrino Mass

A discovery that neutrinos are Majorana fermions would have profound implications for particle physics and cosmology. The Majorana character of neutrinos would make possible the neutrinoless double-β (0νββ) decay, a matter-creating process without the balancing emission of antimatter. The GERDA Collaboration searches for the 0νββ decay of 76Ge by operating bare germanium detectors in an active liquid argon shield. With a total exposure of 82.4 kg⋅year, we observe no signal and derive a lower half-life limit of T1/2 > 0.9 × 1026 years (90% C.L.). Our T1/2 sensitivity, assuming no signal, is 1.1 × 1026 years. Combining the latter with those from other 0νββ decay searches yields a sensitivity to the effective Majorana neutrino mass of 0.07 to 0.16 electron volts.

scholarly journals Neutrinoless Double-Beta Decay

2012 ◽  
Vol 2012 ◽  
pp. 1-38 ◽  
Author(s):  
Andrea Giuliani ◽  
Alfredo Poves
Keyword(s):  
Beta Decay ◽  
Particle Physics ◽  
Nuclear Physics ◽  
Experimental Situation ◽  
Neutrinoless Double Beta Decay ◽  
Majorana Neutrino ◽  
Double Beta Decay ◽  
Point Of View ◽  
The Status ◽  
Majorana Neutrino Mass

This paper introduces the neutrinoless double-beta decay (the rarest nuclear weak process) and describes the status of the research for this transition, both from the point of view of theoretical nuclear physics and in terms of the present and future experimental scenarios. Implications of this phenomenon on crucial aspects of particle physics are briefly discussed. The calculations of the nuclear matrix elements in case of mass mechanisms are reviewed, and a range for these quantities is proposed for the most appealing candidates. After introducing general experimental concepts—such as the choice of the best candidates, the different proposed technological approaches, and the sensitivity—we make the point on the experimental situation. Searches running or in preparation are described, providing an organic presentation which picks up similarities and differences. A critical comparison of the adopted technologies and of their physics reach (in terms of sensitivity to the effective Majorana neutrino mass) is performed. As a conclusion, we try to envisage what we expect round the corner and at a longer time scale.

scholarly journals Lepton masses and mixings in a T′ flavored 3-3-1 model with type I and type II seesaw mechanisms

2019 ◽  
Vol 34 (01) ◽  
pp. 1950005 ◽  
Author(s):  
V. V. Vien ◽  
H. N. Long ◽  
A. E. Cárcamo Hernández
Keyword(s):  
Neutrino Mass ◽  
Mass Parameter ◽  
Majorana Neutrino ◽  
Type I ◽  
Mass Hierarchy ◽  
Type Ii ◽  
Lepton Sector ◽  
Neutrino Mass Hierarchy ◽  
Majorana Neutrinos ◽  
Majorana Neutrino Mass

We propose a renormalizable T′ flavor model based on the [Formula: see text] gauge symmetry, consistent with the observed pattern of lepton masses and mixings. The small masses of the light active neutrinos are produced from an interplay of type I and type II seesaw mechanisms, which are induced by three heavy right-handed Majorana neutrinos and three [Formula: see text] scalar antisextets, respectively. Our model is only viable for the scenario of normal neutrino mass hierarchy, where the obtained physical observables of the lepton sector are highly consistent with the current neutrino oscillation experimental data. In addition, our model also predicts an effective Majorana neutrino mass parameter of [Formula: see text] eV, a Jarlskog invariant of the order of [Formula: see text] and a leptonic Dirac CP violating phase of [Formula: see text], which is inside the [Formula: see text] experimentally allowed range.

The Half-life of 130Te Double β-decay

1966 ◽  
Vol 21 (1-2) ◽  
pp. 84-90 ◽  
Author(s):  
N. Takaoka ◽  
K. Ogata
Keyword(s):  
Half Life ◽  
High Sensitivity ◽  
General Tendency ◽  
Β Decay ◽  
A Value ◽  
Three Samples ◽  
Isotopic Analyses ◽  
Isotopic Abundances ◽  
Double Β Decay ◽  
Small Excess

In order to determine the half-life of the 130Te double β-decay, the amounts and isotopic composition of xenon extracted from tellurium ores, from the Oya gold mine in Japan, have been measured with a high-sensitivity mass spectrometer. Compared with atmospheric xenon an excess was definitely found at mass numbers 129, 130 and 131 in the extracted xenon. The excess of 130Xe is predominant, the average amount in three samples being (1.32 ± 0.09) × 10-11 ccSTP/g 130Te. Attributing the excess 130Xe to the double β-decay of 130Te, the half-life is estimated to be (8.20 ± 0.64) × 1020 years, assuming an age of (9.06 ± 0.29) × 107 years for the Te ores. The latter value is the K-Ar age of porphyrite, which is in close geological connection with the Te ores.In order to investigate the other excesses than that of 130Xe, isotopic analyses were also carried out on Xe from three other Te ores from the same mine. The ratios (129Xe/131Xe) excess=1.58 and (129Xe/130Xe) excess = 2.1 were found to be the same for all samples. The origin of these excesses is discussed.In addition a small excess of 128Xe was found. If this is attributed to 128Te double β-decay, the half-life of 128Te is estimated to be 3 × 1022 years, a value shorter by about three orders of magnitude than the theoretically expected half-life. The above estimated half-life may be a lower limit of the 128Te half-life.The general tendency of the isotopic abundances (except for the above excesses), of the xenon extracted from Te ores seems to be to slightly increase in excess as one moves toward the lighter isotopes (as compared with atmospheric xenon).

scholarly journals Nuclear transition matrix elements for neutrinoless double-β decay within mechanisms involving light Majorana neutrino mass and right-handed current

2019 ◽  
Vol 28 (01n02) ◽  
pp. 1950001
Author(s):  
Yash Kaur Singh ◽  
R. Chandra ◽  
K. Chaturvedi ◽  
Tripti Avasthi ◽  
P. K. Rath ◽  
...  
Keyword(s):  
Neutrino Mass ◽  
Transition Matrix ◽  
Weak Coupling ◽  
Majorana Neutrino ◽  
Nuclear Transition ◽  
Matrix Elements ◽  
Β Decay ◽  
Hartree Fock ◽  
Transition Matrix Elements ◽  
Majorana Neutrino Mass

Employing the projected-Hartree-Fock-Bogoliubov (PHFB) model in conjunction with four different parametrizations of pairing plus multipolar effective two-body interaction and three different parametrizations of Jastrow short-range correlations, nuclear transition matrix elements for the neutrinoless double-[Formula: see text] decay of [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text] isotopes are calculated within mechanisms involving light Majorana neutrino mass and right-handed current. Statistically, model specific uncertainties in sets of twelve nuclear transition matrix elements are estimated by calculating the averages along with the standard deviations. For the considered nuclei, the most stringent extracted on-axis limits on the effective light Majorana neutrino mass [Formula: see text], the effective weak coupling of right-handed leptonic current with right-handed hadronic current [Formula: see text], and the effective weak coupling of right-handed leptonic current with left-handed hadronic current [Formula: see text] from the observed limit on half-life [Formula: see text] of [Formula: see text] isotope are [Formula: see text][Formula: see text]eV, [Formula: see text] and [Formula: see text], respectively.

Half-life limits on the zero-neutrino and two-neutrino double-β decay ofGe76

1986 ◽  
Vol 33 (9) ◽  
pp. 2737-2739 ◽  
Author(s):  
D. O. Caldwell ◽  
R. M. Eisberg ◽  
D. M. Grumm ◽  
D. L. Hale ◽  
M. S. Witherell ◽  
...  
Keyword(s):  
Half Life ◽  
Β Decay ◽  
Double Β Decay

scholarly journals Neutrinoless double-beta decay: A probe of physics beyond the Standard Model

2015 ◽  
Vol 30 (04n05) ◽  
pp. 1530001 ◽  
Author(s):  
S. M. Bilenky ◽  
C. Giunti
Keyword(s):  
Standard Model ◽  
Present Status ◽  
Majorana Neutrino ◽  
Lepton Number ◽  
Double Beta Decay ◽  
Neutrino Masses ◽  
Beyond The Standard Model ◽  
Β Decay ◽  
The Standard Model ◽  
Double Β Decay

In the Standard Model the total lepton number is conserved. Thus, neutrinoless double-β decay, in which the total lepton number is violated by two units, is a probe of physics beyond the Standard Model. In this review we consider the basic mechanism of neutrinoless double-β decay induced by light Majorana neutrino masses. After a brief summary of the present status of our knowledge of neutrino masses and mixing and an introduction to the seesaw mechanism for the generation of light Majorana neutrino masses, in this review we discuss the theory and phenomenology of neutrinoless double-β decay. We present the basic elements of the theory of neutrinoless double-β decay, our view of the present status of the challenging problem of the calculation of the nuclear matrix element of the process and a summary of the experimental results.

Isotopenanalyse der Edelgase in einem Tellurerz von Boliden (Schweden)

1967 ◽  
Vol 22 (11) ◽  
pp. 1783-1792 ◽  
Author(s):  
T. Kirsten ◽  
W. Gentner ◽  
O. Müller
Keyword(s):  
Neutron Flux ◽  
Lower Limit ◽  
Half Life ◽  
Atmospheric Composition ◽  
Selenium Content ◽  
Β Decay ◽  
Subsequent Decay ◽  
Double Β Decay

The stable He-, Ne-, Ar-, Kr- and Xe-isotopes and the Te-, K-, U-, Th- and Se-concentrations in a Precambrian bismuth-tellurium ore have been measured. We have found an age of 0.53 x 109 y with K-Ar, 0.55 x 109 y with U/Th-He4 and 1.56 x 109 y by the U-Xe136 method.The Xe131-excess and part of the Xe129-excess result from n-capture and subsequent decay of Te128and Te130. The remaining part of the Xe129-excess and the high U-Xe136 age give evidence for a higher neutron flux before the last cooling of the ore. The tellurium was probably associated with much more uranium than now. Before 0.54 x 109 y, differentiation of this uranium occured. Moreover, He and Ar but not all of the Xe were removed at this time. After cooling, the Xe129excess was formed by the decay of the long-lived I129 which had been formed from (n,γ) reactions on Te128 by the higher neutron flux.From the excess in Xe130, a half life for the double β-decay of Te130 of 6.2 x 1020 y is calculated.Besides fission-Kr, there is an excess of Kr with atmospheric composition and in addition an excess of Kr82 and Kr83 also. From the Kr82-excess and the selenium content a lower limit for the Se82-double β-decay half life of T1/2≥ 1018 y is calculated. No evidence is given for Ar38 from U-fission.

Nuclear transition matrix elements for neutrinoless double-β decay of 76Ge isotope within PHFB approach

2019 ◽  
Vol 28 (11) ◽  
pp. 1950096
Author(s):  
P. K. Rath ◽  
A. Kumar ◽  
R. Chandra ◽  
R. Gautam ◽  
P. K. Raina ◽  
...  
Keyword(s):  
Transition Matrix ◽  
Tensor Decomposition ◽  
Nuclear Transition ◽  
Matrix Elements ◽  
Spin Tensor ◽  
Β Decay ◽  
Hartree Fock ◽  
Transition Matrix Elements ◽  
Majorana Neutrinos ◽  
Double Β Decay

Employing projected–Hartree–Fock–Bogoliubov (PHFB) model, nuclear transition matrix elements (NTMEs) [Formula: see text] for the neutrinoless double-[Formula: see text] decay of [Formula: see text]Ge isotope are calculated within mechanisms involving light as well as heavy Majorana neutrinos, and classical Majorons. By considering the spin-tensor decomposition of realistic KUO and empirical JUN45 effective two-body interactions, it is noticed that the effect due to SRC on NTMEs [Formula: see text] and [Formula: see text] involving the exchange of light and heavy Majorana neutrinos, respectively, is maximally incorporated by the central part of the effective two-body interaction, which varies by a small amount with the inclusion of spin-orbit and tensor components. Presently, the model-dependent uncertainties in the average NTMEs [Formula: see text] and [Formula: see text] turn out to be about 10% and 37%, respectively.

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