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Search Results: 1 - 10 of 200943 matches for " V. I. Kopeikin "
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On Search for New Physics in Nonequilibrium Reactor Antineutrino Energy Spectrum
V. I. Kopeikin
Physics , 2001, DOI: 10.1134/1.1563708
Abstract: The calculations of the time-dependent reactor antineutrino energy spectrum are presented. Some problems associated with sensitive searches for neutrino magnetic moment and neutrino oscillations in reactor antineutrino flux are considered.
Search for the Neutrino Magnetic Moment in the Non-Equilibrium Reactor Antineutrino Energy Spectrum
V. I. Kopeikin,L. A. Mikaelyan,V. V. Sinev
Physics , 1999, DOI: 10.1134/1.855741
Abstract: We study the time evolution of the typical nuclear reactor antineutrino energy spectrum during reactor ON period and the decay of the residual antineutrino spectrum after reactor is stopped. We find that relevant variations of the soft recoil electron spectra produced via weak and magnetic ${\widetilde {\nu}}_{e},e$ scattering process can play a signigicant role in the current and planned searches for the neutrino magnetic moment at reactors.
Inelastic Scattering of Tritium-Source Antineutrinos on Electrons of Germanium Atoms
V. I. Kopeikin,L. A. Mikaelyan,V. V. Sinev
Physics , 2003, DOI: 10.1134/1.1575570
Abstract: Processes of the inelastic magnetic and weak scattering of tritium-beta-source antineutrinos on the bound electrons of a germanium atom are considered. The results obtained by calculating the spectra and cross sections are presented for the energy-transfer range between 1 eV and 18 keV.
Inverse Beta Decay in a Nonequilibrium Antineutrino Flux from a Nuclear Reactor
V. I. Kopeikin,L. A. Mikaelyan,V. V. Sinev
Physics , 2001, DOI: 10.1134/1.1378874
Abstract: The evolution of the reactor antineutrino spectrum toward equilibrium above the inverse beta-decay threshold during the reactor operating period and the decay of residual antineutrino radiation after reactor shutdown are considered. It is found that, under certain conditions, these processes can play a significant role in experiments seeking neutrino oscillations.
On Possibilities of Studying of Supernova Neutrinos at BAKSAN
Domogatsky, G. V.;Kopeikin, V. I.;Mikaelyan, L. A.;Sinev, V. V.
High Energy Physics - Phenomenology , 2007, DOI: 10.1134/S1063778807060105
Abstract: We consider the possibilities of studying a supernova collapse neutrino burst at Baksan Neutrino Observatory (Institute for Nuclear Research, Russian Academy of Sciences) using the prposed 5-kt target-mass liquid scintillation spectrometer. Attention is given to the influence of mixing angle ${\theta}_{13}$ on the expected rates and spectra of neutrino events.
Numerical Data-Processing Simulations of Microarcsecond Classical and Relativistic Effects in Space Astrometry
Sergei M. Kopeikin,N. V. Shuygina,M. V. Vasilyev,E. I. Yagudina,L. I. Yagudin
Physics , 2000,
Abstract: The accuracy of astrometric observations conducted via a space-borne optical interferometer orbiting the Earth is expected to approach a few microarcseconds. Data processing of such extremely high-precision measurements requires access to a rigorous relativistic model of light ray propagation developed in the framework of General Relativity. The data-processing of the space interferometric observations must rely upon the theory of general-relativistic transformations between the spacecraft, geocentric, and solar barycentric reference systems allowing unique and unambiguous interpretation of the stellar aberration and parallax effects. On the other hand, the algorithm must also include physically adequate treatment of the relativistic effect of light deflection caused by the spherically-symmetric (monopole-dependent) part of the gravitational field of the Sun and planets as well as the quadrupole- and spin-dependent counterparts of it. In some particular cases the gravitomagnetic field induced by the translational motion of the Sun and planets should be also taken into account for unambigious prediction of the light-ray deflection angle. In the present paper we describe the corresponding software program for taking into account all classical (proper motion, parallax, etc.) and relativistic (aberration, deflection of light) effects up to the microarcsecond threshold and demonstrate, using numerical simulations, how observations of stars and/or quasars conducted on board a space optical interferometer orbiting the Earth can be processed and disentangled.
Electromagnetic Pulse Propagation Over Nonuniform Earth Surface: Numerical Simulation
Alexei V. Popov;Vladimir V. Kopeikin
PIER B , 2008, DOI: 10.2528/PIERB08031102
Abstract: Computational aspects of EM pulse propagation along the nonuniform earth surface are considered. For ultrawide-band pulses without carrier, the exact wave equation in a narrow vicinity of the wave front is reduced to a time-domain version of the Leontovich- Fock parabolic equation. To solve it by finite differences, we introduce a time-domain analog of the impedance BC and a nonlocal BC of transparency. Numerical examples are given to demonstrate the influence of soil conductivity on the received pulse waveform. For a high-frequency modulated EM pulse, we develop an asymptotic approach based on the ray structure of the monochromatic wave field calculated at the carrier frequency. As an example, a problem of target altitude determination from overland radar data is considered.
Electromagnetic Pulse Propagation over Nonuniform Earth Surface: Numerical Simulation
Alexei V. Popov,Vladimir V. Kopeikin
Mathematics , 2007,
Abstract: We simulate EM pulse propagation along the nonuniform earth surface using so called time-domain parabolic equation. To solve it by finite differences, we introduce a time-domain analog of the impedance boundary condition and a nonlocal BC of transparency reducing open computational domain to a strip of finite width. Numerical examples demonstrate influence of soil conductivity on the wide-band pulse waveform. For a high-frequency modulated EM pulse, we develop an asymptotic approach based on the ray structure of the monochromatic wave field at carrier frequency. This radically diminishes the computation costs and allows for pulsed wave field calculation in vast domains measured by tens of thousands wavelengths.
The Kr2Det project: Search for mass-3 state contribution |U_{e3}|^2 to the electron neutrino using a one reactor - two detector oscillation experiment at Krasnoyarsk underground site
V. Martemianov,L. Mikaelyan,V. Sinev,V. Kopeikin,Yu. Kozlov
Physics , 2002, DOI: 10.1134/1.1619504
Abstract: The main physical goal of the project is to search with reactor antineutrinos for small mixing angle oscillations in the atmospheric mass parameter region around {\Delta}m^{2}_{atm} ~ 2.5 10^{-3} eV^2 in order to find the element U_{e3} of the neutrino mixing matrix or to set a new more stringent constraint (U_{e3} is the contribution of mass-3 state to the electron neutrino flavor state). To achieve this we propose a "one reactor - two detector" experiment: two identical antineutrino spectrometers with $\sim$50 ton liquid scintillator targets located at ~100 m and ~1000 m from the Krasnoyarsk underground reactor (~600 mwe). In no-oscillation case ratio of measured positron spectra of the \bar{{\nu}_e} + p \to e^{+} + n reaction is energy independent. Deviation from a constant value of this ratio is the oscillation signature. In this scheme results do not depend on the exact knowledge of the reactor power, nu_e spectra, burn up effects, target volumes and, which is important, the backgrounds can periodically be measured during reactor OFF periods. In this letter we present the Krasnoyarsk reactor site, give a schematic description of the detectors, calculate the neutrino detection rates and estimate the backgrounds. We also outline the detector monitoring and calibration procedures, which are of a key importance. We hope that systematic uncertainties will not accede 0.5% and the sensitivity U^{2}_{e3} ~4 10^{-3} (at {\Delta}m^{2} = 2.5 10^{-3} eV^2) can be achieved.
On the Gravitomagnetic Time Delay
I. Ciufolini,S. Kopeikin,B. Mashhoon,F. Ricci
Physics , 2002, DOI: 10.1016/S0375-9601(02)01804-2
Abstract: We study the gravitational time delay in ray propagation due to rotating masses in the linear approximation of general relativity. Simple expressions are given for the gravitomagnetic time delay that occurs when rays of radiation cross a slowly rotating shell and propagate in the field of a distant rotating source. Moreover, we calculate the local gravitational time delay in the Goedel universe. The observational consequences of these results in the case of weak gravitational lensing are discussed.
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