KATRIN—a new tritium beta decay experiment to study the electron neutrino mass in the sub-eV range

Author(s):  
1986 ◽  
Vol 266 (3-4) ◽  
pp. 669-686 ◽  
Author(s):  
Paul Langacker ◽  
B. Sathiapalan ◽  
Gary Steigman

2020 ◽  
Vol 9 ◽  
pp. 14
Author(s):  
A. Faessler

The standard model predicts a ratio of 2 for the number of atmospheric muon to electron neutrinos, while super-Kamiokande and others measure a much smaller value (1.30±0.02 for super-Kamiokande). Super-Kamiokande is also able to measure roughly the direction and the energy of the neutrinos. The zenith-angle dependence for the muon neutrinos suggests that the muon neutrinos oscillate into a third neutrino species, either into the r neutrino or a sterile neutrino. This finding is inves- tigated within the supersymmetric model. The neutrinos mix with the neutralinos, this meaning the wino, the bino and the two higgsinos. The 7 x 7 mass matrix is calculated on the tree level. One finds that the mass matrix has three linearly dependent rows, which means that two masses are zero. They are identified with the two lightest neutrino masses. The fit of the super-Kamiokande data to oscillations between three neutrinos yields, together with the result of supersymmetry, that the third neutrino mass lies between 2x10^-2 and 10^-1 eV. The two lightest neutrino masses are in supersymmetry on the tree level zero. The averaged electron neutrino mass which is the essential parameter in the neutrinoless double-beta decay is given by {m_ve) ~ m_v3 P_ze < 0.8 x10^-2 eV (95% confidence limit). It is derived from the super-Kamiokande data in this supersymmetric model to be two orders smaller than the best value (1 eV) from the neutrinoless double-beta decay.


1982 ◽  
Author(s):  
B. Jonson ◽  
J. U. Andersen ◽  
G. J. Beyer ◽  
G. Charpak ◽  
A. De Rújula ◽  
...  

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Sabin Stoica ◽  
Andrei Neacsu

The study of the neutrinoless double beta(0νββ)decay mode can provide us with important information on the neutrino properties, particularly on the electron neutrino absolute mass. In this work we revise the present constraints on the neutrino mass parameters derived from the0νββdecay analysis of the experimentally interesting nuclei. We use the latest results for the phase space factors (PSFs) and nuclear matrix elements (NMEs), as well as for the experimental lifetime limits. For the PSFs we use values computed with an improved method reported very recently. For the NMEs we use values chosen from the literature on a case-by-case basis, taking advantage of the consensus reached by the community on several nuclear ingredients used in their calculation. Thus, we try to restrict the range of spread of the NME values calculated with different methods and, hence, to reduce the uncertainty in deriving limits for the Majorana neutrino mass parameter. Our results may be useful to have an updated image on the present neutrino mass sensitivities associated with0νββmeasurements for different isotopes and to better estimate the range of values of the neutrino masses that can be explored in the future double beta decay (DBD) experiments.


1983 ◽  
Vol 396 ◽  
pp. 479-493 ◽  
Author(s):  
B. Jonson ◽  
J.U. Andersen ◽  
G.J. Beyer ◽  
G. Charpak ◽  
A. De Rújula ◽  
...  

1978 ◽  
Vol 56 (4) ◽  
pp. 399-402 ◽  
Author(s):  
Charles Picciotto

Double-beta decay half-lives are calculated with the assumption that the emission of electron–neutrino pairs occurs via a Δ(1232) resonance in the nucleus. Numerical results are obtained with a quark model for the hadrons. By assuming that total rates are produced by a combination of neutrinoless and two-nuetrino modes, a lepton-nonconservation parameter η ~ 10−5 is obtained. Although the actual modes of decay and underlying mechanisms are undetermined, the present calculation can be used to obtain an upper limit for the probability admixture of resonances in the nucleus of a few percent.


2016 ◽  
Vol 31 (38) ◽  
pp. 1650207 ◽  
Author(s):  
M. Sruthilaya ◽  
Srinu Gollu

To accommodate the recently observed nonzero reactor mixing angle [Formula: see text], we consider the lepton mixing matrix as tri-bimaximal mixing (TBM) form in the leading order along with a perturbation in neutrino sector. The perturbation is taken to be a rotation in 23 plane followed by a rotation in 13 plane, i.e. [Formula: see text]. We obtain the allowed values of the parameters [Formula: see text], [Formula: see text] and [Formula: see text], which can accommodate all the observed mixing angles consistently and calculate the phenomenological observables such as the Dirac CP violating phase [Formula: see text], Jarlskog invariant [Formula: see text], effective Majorana mass [Formula: see text] and [Formula: see text], the electron neutrino mass. We find that [Formula: see text] can take any values between [Formula: see text] and [Formula: see text] and [Formula: see text] always comes below its experimental upper limit.


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