arXiv subjects

S. V. Fomichev

Publications and source records attributed to S. V. Fomichev.

12 recordsLinked to original sources

arXiv2025

On phenomenological relations for masses and mixing parameters of quarks and leptons

A comparative analysis of a number of phenomenological relationships between constants of the extended Standard Model of electromagnetic, strong and weak interactions of fundamental particles (hereinafter referred to as the extended Standard Model) is carried out to detect possible correlations between constants in the quark and lepton sectors. The presence of such correlations may indicate connections between constants within a more general theory than the extended Standard Model. Phenomenological relationships between masses of current and constituent quarks and mixing angles are considered. A phenomenological relationship between neutrino masses and neutrino mixing angle is found. The quark-lepton complementarity relationship for quark and neutrino mixing angles is confirmed. A typical estimate of the accuracy of such relationships is given. Estimates of the masses of sterile (right-handed) neutrinos are obtained at the phenomenological level using the seesaw mechanism. In this case, it is assumed that the values of the active neutrino masses depend on three characteristic scales, and the sum of the active neutrino masses is limited from above by $0.06$~eV. An example of a grand unification theory and possible stages of spontaneous breaking of its gauge symmetry to the level of gauge symmetry of the extended Standard Model due to additional Higgs particles are considered.

hep-ph↗

arXiv2025

Estimates of the masses of heavy right-handed neutrino particles using the seesaw mechanism

The mass estimates of active and sterile (right-handed) neutrinos are considered at the phenomenological level using the seesaw mechanism. It is assumed that the neutrino mass values depend on three characteristic scales, and the sum of the active neutrino mass values is limited from above by 0.06 eV. The neutrino mass values are estimated, as well as the observable neutrino mass values, namely, the average mass m_C of active neutrinos and the kinematic neutrino mass m_β of beta-decay.

hep-ph↗

arXiv2024

Active and sterile neutrino oscillations inside the Sun in a phenomenological (3+1+2)-model

The phenomenological model with three active and three light sterile neutrinos is considered taking into account terrestrial experimental data, which indicate anomalies at short distances beyond the minimally modified Standard Model with three massive active neutrinos. One of the sterile neutrinos is assumed to have distinctly different mass in comparison with masses of two others, that is corresponding to a $(3+1+2)$-model of neutrinos. Model parameters values used for the description of oscillations of both active and sterile massive neutrinos into the Sun are chosen. Oscillation characteristics of solar neutrinos together with sterile neutrinos contributions have been evaluated taking into account the neutrino interaction with the matter inside the Sun with the use of the standard solar model (SSM). Results obtained correlate with observational data and can be used for development of sterile neutrinos models.

hep-ph↗

arXiv2023

Light sterile neutrinos effects in processes with electron and muon neutrinos

Sterile neutrinos with various masses could be participated in astrophysical and cosmological processes including mixing with active neutrinos, if exist. It is considered the possible effects of mixing of active and sterile neutrinos with masses of the order or less than 1 eV. For oscillation processes involving electron and muon neutrinos, as well as for beta decay and neutrinoless double beta decay processes, the contributions of light sterile neutrinos in the characteristics of these processes are calculated. For this purpose the estimates of the mixing parameters in the model with three active and three sterile neutrinos are made taking into account experimental data. Two cases of sterile neutrinos masses distribution are considered in detail. The results obtained can be used for interpretation of available experimental data, and also for predictions of subsequent experimental results.

hep-ph↗

arXiv2020

Active neutrino oscillations and double beta decay characteristics with sterile neutrinos contributions

Light sterile neutrinos contributions both for active neutrinos oscillations and neutrinoless double beta decay characteristics are estimated in the framework of the phenomenological model with three active and three sterile neutrinos assuming the Majorana nature of neutrino. Appearance and survival probabilities for active neutrinos with contributions of eV-sterile neutrinos in application to the short-baseline anomalies in neutrino data are obtained at the same test values of the model parameters. Modified graphical dependences for the survival probability of electron neutrinos/antineutrinos and the probability of appearance of electron neutrinos/antineutrinos in muon neutrino/antineutrino beams as functions of distance and other model parameters at different neutrino energies, and also as functions of the ratio of the distance to the neutrino energy are presented. A significant difference was found between the probability curves of the considered neutrino model and the simple sinusoidal curves of the neutrino model with one sterile neutrino. Effective electron neutrino masses for the beta decay and the neutrinoless double beta decay are estimated with account of eV-sterile neutrinos contributions. Besides, the two-neutrino double beta decay characteristics for selenium-82 are calculated. These findings can be used for interpretation and prediction of results of ground-based experiments on search for the sterile neutrinos as well as the neutrinoless double beta decay.

hep-ph↗

arXiv2019

Sterile neutrinos influence on oscillation characteristics of active neutrinos at short distances in the generalized model of neutrino mixing

A phenomenological model with active and sterile neutrinos is used for calculations of neutrino oscillation characteristics at the normal mass hierarchy of active neutrinos. Taking into account the contributions of sterile neutrinos, appearance and survival probabilities for active neutrinos are calculated. Modified graphical dependencies for the probability of appearance of electron neutrinos/antineutrinos in muon neutrino/antineutrino beams as a function of the ratio of the distance to the neutrino energy and other model parameters are obtained. It is shown that in the case of a certain type mixing between active and sterile neutrinos it is possible to clarify some features of the anomalies of neutrino data at short distances. A new parametrization for a particular type mixing matrix of active and sterile neutrinos that takes into account the additional sources of CP violation is used. The comparison with the existing experimental data is performed and, with using this knowledge, the estimates of some model parameters are found. The theoretical results obtained for mixing of active and sterile neutrinos can be applied for interpretation and prediction of results of ground-based experiments on search of sterile neutrinos as well as for analyses of some astrophysical data.

hep-ph↗

arXiv2017

Neutrino Fluxes from a Core-Collapse Supernova in a Model with Three Sterile Neutrinos

The characteristics of the gravitational collapse of a supernova and the fluxes of active and sterile neutrinos produced during the formation of its protoneutron core have been calculated numerically. The relative yields of active and sterile neutrinos in core matter with different degrees of neutronization have been calculated for various input parameters and various initial conditions. A significant increase in the fraction of sterile neutrinos produced in superdense core matter at the resonant degree of neutronization has been confirmed. The contributions of sterile neutrinos to the collapse dynamics and the total flux of neutrinos produced during collapse have been shown to be relatively small. The total luminosity of sterile neutrinos is considerably lower than the luminosity of electron neutrinos, but their spectrum is considerably harder at high energies.

astro-ph.HE↗

arXiv2016

Oscillation characteristics of active and sterile neutrinos and neutrino anomalies at shot distances

A generalized phenomenological (3 + 2 + 1)-model with three active and three sterile neutrinos is considered for the calculation of the neutrino oscillation characteristics at normal mass hierarchy of active neutrinos and significant splitting between the mass of one sterile neutrino and the masses of other two sterile neutrinos. A new parametrization and a certain form of the general neutrino mixing matrix for active and sterile neutrinos are suggested taking into account the possible violation of CP invariance in the lepton sector. The test values of the neutrino masses and the mixing parameters are chosen. The transition probabilities for the different flavors of neutrino, which can be transformed into each other, are calculated, and the graphical dependences are obtained for the disappearance probability of muon neutrino/antineutrino and appearance probability of electron neutrino/antineutrino in the muon neutrino/antineutrino jet as a function of distance and other model parameters at their acceptable values and at neutrino energies not higher than 50 MeV, as well as a function of the ratio of the distance to the neutrino energy. It is shown that in the case of the mixing matrix of a definite type (of the a_2 type) between active and sterile neutrinos the explanation of the acceleration anomaly on small distances in the neutrino data (LSND anomaly) is possible, as well as the reactor and gallium anomalies. The theoretical results obtained can be used for the interpretation and prediction of results of the ground-based neutrino experiments on searching for the sterile neutrinos, and also for the analysis of certain astrophysical observation data.

hep-ph↗

arXiv2016

Plasmon-enhanced second harmonic generation in the laser-irradiated cubic metal nanoparticles

The plasmon-enhanced second harmonic generation in the subwavelength neutral metal cubic nanoparticles is calculated for the first time in the hydrodynamic and cold plasma approximations. The theory is developed that takes into account all singularities of the electromagnetic field at the cubic nanoparticle surface. The results are compared to the linear case for the nanocube and to those for a spherical nanoparticle. In the latter case, they demonstrate very strong enhancement of the local field strength and the second harmonic signal.

cond-mat.mes-hall↗

arXiv2015

Enhancement of the sterile neutrinos yield at high matter density and at increasing the medium neutronization

The relative yields of active and sterile neutrinos in the matter with a high density and different degree of neutronization are calculated. A significant increase in the proportion of sterile neutrinos produced in superdense matter when degree of neutronization approaches the value of two is found. The results obtained can be used in the calculations of the neutrino fluxes for media with a high density and different neutronization degrees in astrophysical processes such as the formation of protoneutron core of a supernova.

hep-ph↗

arXiv2015

Mass characteristics of active and sterile neutrinos in a phenomenological (3+1+2)-model

On the basis of the experimental data allowing existence of the anomalies going beyond the minimally extended Standard Model with three active neutrinos with different masses, we consider the generalized model with three active and three sterile neutrinos, one of which is relatively heavy ((3+1+2)-model). We study the basic characteristics that are used to describe the massive active and sterile neutrinos, the methods to determine the absolute scale of neutrino masses and the neutrino mass estimates based on the available experimental data. Taking into account the possible contributions of the sterile neutrinos, the dependences of the neutrino mass characteristics on the sterile neutrino mass are plotted. The results obtained can be used to interpret and to predict the results of various neutrino experiments.

hep-ph↗

arXiv2013

Neutrino mass characteristics in a phenomenological 3+2+1 model

The basic characteristics used for the description of both Dirac and Majorana massive neutrinos are studied. Currently available experimental data for these characteristics are presented with an evidence of possible anomalies beyond the Standard Model with three light neutrinos. Special attention has been paid to ways to determine the neutrino mass absolute scale. In accordance with the available data, the permissible values of the neutrino mass matrix elements are found numerically against the minimal mass of neutrino. Some phenomenological relations for the masses, the angles and the CP-violating phases of the neutrino mixing matrix are discussed, and the values of the neutrino mass characteristics and the Dirac CP-violating phase are evaluated for a model of bimodal neutrinos. The estimations made for masses of sterile neutrinos, the values of the neutrino mass characteristics and the Dirac CP-violating phase can be used for interpretation and prediction of the results of various neutrino experiments.

hep-ph↗