The experiment Neutrino-4 started in 2014 with a detector model and continued with a full-scale detector in 2016–2021. In this article, we describe all the steps of the preparatory work on this ...experiment. We present all results of the Neutrino-4 experiment with increased statistical accuracy provided to date. The experimental setup is constructed to measure the flux and spectrum of the reactor antineutrinos as a function of distance to the center of the active zone of the SM-3 reactor (Dimitrovgrad, Russia) in the range of 6–12 meters. Using all the collected data, we performed a model-independent analysis to determine the oscillation parameters Δm214 and sin22θ14. The method of coherent summation of measurement results allows us to directly demonstrate the oscillation effect. We present the analysis of possible systematic errors and the MC model of the experiment, which considers the possibility of the effect manifestation at the present precision level. As a result of the analysis, we can conclude that at currently available statistical accuracy, we observe the oscillations at the 2.9 σ level with the parameters Δm214 = (7.3 ± 0.13st ± 1.16syst) eV2 = (7.3 ± 1.17) eV2 and sin22θ = 0.36 ± 0.12 stat(2.9σ). Monte Carlo based statistical analysis gave an estimation of the confidence level at 2.7σ. We plan to improve the currently working experimental setup and create a completely new setup in order to increase the accuracy of the experiment by 3 times. We also provide a brief analysis of the general experimental situation in the search for sterile neutrinos.
Abstract
The next core-collapse supernova in the Milky Way or its satellites will represent a once-in-a-generation opportunity to obtain detailed information about the explosion of a star and provide ...significant scientific insight for a variety of fields because of the extreme conditions found within. Supernovae in our galaxy are not only rare on a human timescale but also happen at unscheduled times, so it is crucial to be ready and use all available instruments to capture all possible information from the event. The first indication of a potential stellar explosion will be the arrival of a bright burst of neutrinos. Its observation by multiple detectors worldwide can provide an early warning for the subsequent electromagnetic fireworks, as well as signal to other detectors with significant backgrounds so they can store their recent data. The supernova early warning system (SNEWS) has been operating as a simple coincidence between neutrino experiments in automated mode since 2005. In the current era of multi-messenger astronomy there are new opportunities for SNEWS to optimize sensitivity to science from the next galactic supernova beyond the simple early alert. This document is the product of a workshop in June 2019 towards design of SNEWS 2.0, an upgraded SNEWS with enhanced capabilities exploiting the unique advantages of prompt neutrino detection to maximize the science gained from such a valuable event.
This multidisciplinary study deals with a population cluster of migrant multilinguals as a complex phenomenon of Social Physics with the help of the mathematical-statistical tools. It enlightens two ...statistical methods used to analyse the quantitative data on the plurilingual competence of the university students: the Rasch analysis and the T-test. These methods are able to give a more profound picture of the individual migrants' plurilingual ability in terms of migration as a sociophysical phenomenon. We consider the strengths that each method has as the physical values in order to understand the linguistic behavior of migrant flow as a complex matter and each migrant student as a part of this flow. Our multidisciplinary study empirically investigates whether the positive impact of the statistical methods is relevant by using recent dataset on the example of the multilinguals' social cluster. The main conclusion of the study shows the positive impact of the Rasch model in measurement of complex sociophysical matters with respect to the ability of a migrant social cluster to the plurilingualism, and results in the statement that this tool is capable to decipher the empirical data in a qualitative manner, in particular, for its application to the group educational trajectories. However, T-test showed the statistical insignificance of the current data set if this data set is used to predict further development of plurilingual competence.
We report Neutrino-4 experiment results of measurements of reactor antineutrinos flux and spectrum dependence on the distance in range 6–12 m from the center of the reactor core. The fit of ...experimental dependence with the law 1/
L
2
, where
L
is the distance from the reactor center, gave satisfactory result with goodness of fit 81%. However, we discovered that the experimental neutrino spectrum is different from the calculated one. Using experimental spectrum, we performed the model independent analysis of restrictions on oscillation parameters Δ
m
14
2
and sin
2
2θ
14
. The results of this analysis exclude area of reactor and gallium anomaly at CL more than 99.7% (>3σ) for values Δ
m
14
2
< 3 eV
2
and sin
2
2θ
14
> 0.1. However, we observed an oscillation effect at CL 2.8σ in vicinity of Δ
m
14
2
Δ
m
14
2
≈ 7.3 eV
2
and sin
2
2θ
14
≈ 0.39. The method of coherent addition of results of measurements, which allows us to directly observe the effect of oscillations, is proposed. The analysis of that effect is presented. In general, it seems that the effect predicted in gallium and reactor experiments is being confirmed but at sufficiently large value of Δ
m
14
2
. Future prospects of the experiment are discussed.
The XIII International Conference "Computer-aided technologies in applied mathematics" was successfully held from 7th to 9th of September, 2020, at the National Research Tomsk State University, ...Tomsk, Russia. The conference was organized by National Research Tomsk State University, Angarsk State Technical University and The Institute of Computational Mathematics and Mathematical Geophysics. Originally, the conference was to be held in June on Lake Baikal. But due to the COVID-19 coronavirus pandemic, the dates, venue, and format of the conference were changed. List of Program Committee, Editors, Organizing Institutions, Images are available in this pdf.
(
) and (
) reactions induced by the alpha decays of uranium, thorium, and their daughter nuclides generate the intrinsic neutron and gamma backgrounds in modern ultralow background neutrino and dark ...matter detectors. In order to minimize the background, it is essential to select materials on the basis of a detailed analysis of relative concentrations of radionuclides and calculations of neutron and gamma-radiation yields. The NeuCBOT (Neutron Calculator Based On TALYS) program makes it possible to perform such calculations. The present article gives a review of a new version of the NeuCBOT program and a comparison of the results of calculations with different software tools.
Abstract
Radio wave tomography (radiotommography) allows restoring the shape of objects hidden behind radio-transparent barriers. Radiotommography detectors use this technology for location and ...visualization for metal, metalized, and dielectric communications in walls and floors. An interpretation of tomography images obtained during radio wave measuring is a difficult task for non-specialists. Moreover, they have no visual reference to the objects of the scene under exploration. To simplify a perception and analysis of the obtained data of radio wave measurements, we propose to combine digital radio and optical images of the scene. This article describes the solution to the problem of combining optical and radio wave images. It allows to estimate visually the size and position of the hidden objects.
•The dynamics of the two-component (HF-LF) soliton with initial displacement of the HF component is investigated.•The study is performed in the framework of the Zakharov-type system of coupled ...linear-Schrödinger and KdV equations, with an arbitrary ratio of nonlinearity and dispersion coefficients.•Analytical and numerical results are produced.•The oscillation frequency of the displaced HF component of the two-component soliton is found.•Stability of the perturbed two-component solitons is demonstrated.
The dynamics of two-component solitons with a small spatial displacement of the high-frequency (HF) component relative to the low-frequency (LF) one is investigated in the framework of the Zakharov-type system. In this system, the evolution of the HF field is governed by a linear Schrödinger equation with the potential generated by the LF field, while the LF field is governed by a Korteweg-de Vries (KdV) equation with an arbitrary dispersion-nonlinearity ratio and a quadratic term accounting for the HF feedback on the LF field. The oscillation frequency of the soliton's HF component relative to the LF one is found analytically. It is shown that the solitons are stable against small perturbations. The analytical results are confirmed by numerical simulations.
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