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S. M. Bilenky

Publications and source records attributed to S. M. Bilenky.

At least 55 records · Page 3Linked to original sources
arXiv2005

Neutrino Oscillations and Time-Energy Uncertainty Relation

Neutrino oscillations is a phenomenon which is characterized by a finite oscillation time (length). For such phenomena time-energy uncertainty relation is valid. This means that energy uncertainty is needed for oscillations to occur. We consider neutrino oscillations from this point of view. We demonstrate that for mixed neutrino states, which describe flavor neutrinos $ν_{e}$, $ν_μ$ and $ν_τ$, translational invariance does not take place.

hep-ph↗
arXiv2005

Neutrino Masses, Mixing and Oscillations

Basics of neutrino oscillations is discussed. Importance of time-energy uncertainty relation is stressed. Neutrino oscillations in the leading approximation and evidence for neutrino oscillations are briefly summarized.

hep-ph↗
arXiv2005

Neutrinoless Double $β$-Decay: Status and Future

A brief summary of the status of neutrino masses, mixing and oscillations is presented. Neutrinoless double $β$-decay is considered. Predictions for the effective Majorana mass are reviewed. A possible test of the calculations of nuclear matrix elements of the $0νββ$-decay is proposed.

hep-ph↗
arXiv2005

Neutrinoless double beta decay and neutrino mass hierarchies

In the framework of the see-saw mechanism the normal hierarchy is favorable for the neutrino mass spectrum. For this spectrum we present a detailed calculation of the half-lives of neutrinoless double beta decay for several nuclei of experimental interest. The half-lives are evaluated by considering the most comprehensive nuclear matrix elements, which were obtained within the renormalized QRPA by the Bratislava-Caltech-Tuebingen group. The dependence of the half-lives on sin^2 theta_{13}$ and the lightest neutrino mass is studied. We present also the results of the calculations of the half-lives of neutrinoless double beta decay in the case of the inverted hierarchy of neutrino masses.

hep-ph↗
arXiv2005

Neutrinoless Double $β$-Decay:The Problem of Nuclear Matrix Elements

The calculations of nuclear matrix elements of $0νββ$-decay is a challenge for nuclear physics. We are discussing here a model independent method, which could allow to test the calculations. The method is based on the factorization property of the nuclear matrix elements and requires observation of neutrinoless double $β$-decay of several nuclei.

hep-ph↗
arXiv2004

A Model Independent Approach to Solar Neutrino Experiments

In the first part of this report we present the results of a model independent analysis of the existing solar neutrino data. We obtained forbidden regions in the plane of the parameters Delta m^2 and sin^2 2 theta in two cases: A) Without any restrictions on the values of the solar neutrino fluxes from different reactions; B) With some restrictions that take into account the predictions of all the existing solar models. We show that the existing solar neutrino data allow to exclude rather large regions in the plane of the parameters Delta m^2 and sin^2 2 theta (especially in case B). In the second part of this report we present a general method for the analysis of solar neutrino data that can be applied to future solar neutrino experiments (SNO, Super-Kamiokande, Icarus) in which high energy 8B neutrinos will be detected. We show that these experiments will allow: 1) To reveal in a model independent way the presence of sterile neutrinos in the flux of solar neutrinos on the earth and to obtain lower bounds for the probability of transition of nu_e's into sterile states; 2) To obtain directly from the experimental data the initial 8B nu_e flux and the probability of nu_e's to survive (if there are no transitions of nu_e's into sterile states).

hep-ph↗
arXiv2004

Nuclear Matrix Elements of $0νββ$-Decay: Possible Test of the Calculations

A possible model independent test of the theoretically calculated nuclear matrix elements of $0νββ$-decay is proposed. The test can be accomplished if $0νββ$-decay of three (or more) nuclei is observed. The selection of the nuclei for the next generation of $0νββ$-decay experiments should be done taking into account {\it also} considerations regarding the possibility to test the nuclear matrix element calculations.

hep-ph↗
arXiv2004

A Remark on Neutrino Oscillations Observed in Kamland Experiment

It is demonstrated that the observation of neutrino oscillations in the atmospheric (K2K) neutrino experiments and unitarity of the mixing matrix implies that disappearance of the reactor $\barν_{e}$'s discovered in the KamLAND experiment is due to $\barν_{e}\to \barν_μ$ {\em and} $\barν_{e}\to \barν_τ$ transitions. At $θ_{23}=π/4$ the probabilities of these transitions are equal.

hep-ph↗
arXiv2004

The Majorana neutrino masses, neutrinoless double beta decay and nuclear matrix elements

The effective Majorana neutrino mass is evaluated by using the latest results of neutrino oscillation experiments. The problems of the neutrino mass spectrum,absolute mass scale of neutrinos and the effect of CP phases are addressed. A connection to the next generation of the neutrinoless double beta decay (0nbb-decay) experiments is discussed. The calculations are performed for 76Ge, 100Mo, 136Xe and 130Te by using the advantage of recently evaluated nuclear matrix elements with significantly reduced theoretical uncertainty. An importance of observation of the 0nbb-decay of several nuclei is stressed.

hep-ph↗
arXiv2004

Neutrinoless Double $β$-Decay

The neutrinoless double $β$-decay is reviewed. Model independent evidence in favor of neutrino masses and mixing is briefly summarized. The data of the recent experiments on the search for $0νββ$-decay are presented and some future experiments are discussed. The possible values of the effective Majorana mass, which can be predicted on the basis of the neutrino oscillation data under different assumptions on the pattern of the neutrino mass spectrum, are considered. A possible model independent test of the nuclear matrix element calculations is discussed.

hep-ph↗
arXiv2004

A Lecture on Neutrinos

The major steps in the development of our knowledge about neutrinos are reviewed. The basics of neutrino oscillation formalism is presented. Neutrino oscillations in the framework of three-neutrino mixing are considered. The evidence for neutrino oscillations is discussed.

hep-ph↗
arXiv2003

Looking for strangeness with neutrino-nucleon scattering

The possibility to determine the axial strange form factor of the nucleon from elastic neutrino-nucleon scattering experiments is studied. The existing experimental information is shortly mentioned and several observables which could be measured in the near future at new neutrino facilities are discussed.

hep-ph↗
arXiv2003

Neutrino Oscillations, Masses and Mixing

The original B. Pontecorvo idea of neutrino oscillations is discussed. Neutrino mixing and basics of neutrino oscillations in vacuum and in matter are considered. Recent evidences in favour of neutrino oscillations, obtained in Super-Kamiokande, SNO, KamLAND and other neutrino experiments are discussed. Neutrino oscillations in the solar and atmospheric ranges of the neutrino mass-squared differences are considered in the framework of the minimal scheme with the mixing of three massive neutrinos. Results of the tritium beta-decay experiments and experiments on the search for neutrinoless double-beta-decay are briefly discussed.

hep-ph↗
arXiv2003

Absolute Values of Neutrino Masses: Status and Prospects

Compelling evidences in favor of neutrino masses and mixing obtained in the last years in Super-Kamiokande, SNO, KamLAND and other neutrino experiments made the physics of massive and mixed neutrinos a frontier field of research in particle physics and astrophysics. There are many open problems in this new field. In this review we consider the problem of the absolute values of neutrino masses, which apparently is the most difficult one from the experimental point of view. We discuss the present limits and the future prospects of beta-decay neutrino mass measurements and neutrinoless double-beta decay. We consider the important problem of the calculation of nuclear matrix elements of neutrinoless double-beta decay and discuss the possibility to check the results of different model calculations of the nuclear matrix elements through their comparison with the experimental data. We discuss the upper bound of the total mass of neutrinos that was obtained recently from the data of the 2dF Galaxy Redshift Survey and other cosmological data and we discuss future prospects of the cosmological measurements of the total mass of neutrinos. We discuss also the possibility to obtain information on neutrino masses from the observation of the ultra high-energy cosmic rays (beyond the GZK cutoff). Finally, we review the main aspects of the physics of core-collapse supernovae, the limits on the absolute values of neutrino masses from the observation of SN1987A neutrinos and the future prospects of supernova neutrino detection.

hep-ph↗
arXiv2002

The possible test of the calculations of nuclear matrix elements of the $(ββ)_{0ν}$-decay

The existing calculations of the nuclear matrix elements of the neutrinoless double $β$-decay differ by about a factor three. This uncertainty prevents quantitative interpretation of the results of experiments searching for this process. We suggest here that the observation of the neutrinoless double $β$-decay of {\em several} nuclei could allow to test calculations of the nuclear matrix elements through the comparison of the ratios of the calculated lifetimes with experimental data. It is shown that the ratio of the lifetimes is very sensitive to different models.

hep-ph↗