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D. A. Rumyantsev

Publications and source records attributed to D. A. Rumyantsev.

13 recordsLinked to original sources
arXiv2015

Neutrino processes $ν\barν\to e^- e^+$ and $ν\to νe^- e^+$ in a strong magnetic field

The processes of neutrino production of electron-positron pairs, $ν\barν\to e^- e^+$ and $ν\to νe^- e^+$, in a magnetic field of arbitrary strength, where electrons and positrons can be created in the states corresponding to excited Landau levels, are analysed. The results can be applied for calculating the efficiency of the electron-positron plasma production by neutrinos in the conditions of the Kerr black hole accretion disc considered by experts as the most possible source of a short cosmological gamma burst.

hep-ph↗
arXiv2015

Generalized two-point tree-level amplitude $jf \to j^{\, \prime} f^{\, \prime}$ in a magnetized medium

The tree-level two-point amplitudes for the transitions $jf \to j^{\, \prime} f^{\, \prime}$, where $f$ is a fermion and $j$ is a generalized current, in a constant uniform magnetic field of an arbitrary strength and in charged fermion plasma, for the $jff$ interaction vertices of the scalar, pseudoscalar, vector and axial-vector types have been calculated. The generalized current $j$ could mean the field operator of a boson, or a current consisting of fermions, e.g. the neutrino current. The particular cases of a very strong magnetic field, and of the coherent scattering off the real fermions without change of their states (the "forward" scattering) have been analysed. The contribution of the neutrino photoproduction process, $γe\to e ν\bar ν$, to the neutrino emissivity has been calculated with taking account of a possible resonance on the virtual electron.

hep-ph↗
arXiv2014

Neutrino photoproduction on electron in dense magnetized medium

The effect of a strongly magnetized cold plasma on the Compton-like photoproduction of a neutrino-antineutrino pair on an electron, $γe \to e ν\bar ν$, has been considered. The contribution of this process to the neutrino emissivity in both the non-resonance and the resonance cases has been calculated with taking account of the photon dispersion properties in medium. Our results show that the neutrino emissivity owing to the $γe \to e ν\bar ν$ reaction is significantly modified as compared to the previously reported data.

hep-ph↗
arXiv2014

Generalized two-point tree-level amplitude $jf \to j^{\, \prime} f^{\, \prime}$ in a magnetized medium (extended version)

The tree-level two-point amplitudes for the transitions $jf \to j^{\, \prime} f^{\, \prime}$, where $f$ is a fermion and $j$ is a generalized current, in a constant uniform magnetic field of an arbitrary strength and in charged fermion plasma, for the $jf$ interaction vertices of the scalar, pseudoscalar, vector and axial-vector types have been investigated. The particular cases of a very strong magnetic field, and of the coherent scattering off the real fermions without change of their states (the "forward" scattering) have been analysed.

hep-ph↗
arXiv2014

Neutrino production of electron-positron pairs at excited Landau levels in a strong magnetic field

The process of neutrino production of electron positron pairs in a magnetic field of arbitrary strength, where electrons and positrons can be created in the states corresponding to excited Landau levels, is analysed. The mean value of the neutrino energy loss due to the process $ν\to νe^- e^+$ is calculated. The result can be applied for calculating the efficiency of the electron-positron plasma production by neutrinos in the conditions of the Kerr black hole accretion disc considered by experts as the most possible source of a short cosmological gamma burst. The presented research can be also useful for further development of the calculation technic for an analysis of quantum processes in external active medium, and in part in the conditions of moderately strong magnetic field, when taking account of the ground Landau level appears to be insufficient.

hep-ph↗
arXiv2014

Creation of electron-positron pairs at excited Landau levels by neutrino in a strong magnetic field

The process of neutrino production of electron positron pairs in a magnetic field of arbitrary strength, where electrons and positrons can be created in the states corresponding to excited Landau levels, is analysed. The mean value of the neutrino energy loss due to the process $ν\to νe^- e^+$ is calculated. The result can be applied for calculating the efficiency of the electron-positron plasma production by neutrinos in the conditions of the Kerr black hole accretion disc considered by experts as the most possible source of a short cosmological gamma burst. The presented research can be also useful for further development of the calculation technic for an analysis of quantum processes in external active medium, and in part in the conditions of moderately strong magnetic field, when taking account of the ground Landau level appears to be insufficient.

hep-ph↗
arXiv2012

Photon splitting and Compton scattering in strongly magnetized hot plasma

The process of photon splitting is investigated in the presence of strongly magnetized electron-positron plasma. The amplitude of the process is calculated in general case of plasma with nonzero chemical potential and temperature. The polarization selection rules and corresponding partial amplitudes for allowed splitting channels are obtained in the case of charge-symmetric plasma. It is found that the new splitting channel forbidden in magnetized vacuum becomes allowed. The absorption rates of the photon splitting are calculated with taking into account of the photon dispersion and wave function renormalization. In addition, the comparison of photon splitting and Compton scattering process is made. The influence of the reactions under consideration on the radiation transfer in the framework of magnetar model of SGR burst is discussed.

hep-ph↗
arXiv2010

Resonant $γ\to a$ transition in magnetar magnitosphere

The effect of a magnetized plasma on the resonant photoproduction of axions on the electromagnetic multipole components of the medium, $i \to f+a$, has been considered. It has been shown that the axion resonant emissivity, due to various reactions involving particles of the medium, is naturally expressed in terms of the emissivity of the photon $\to$ axion transition. The number of axions produced by the equilibrium cosmic microwave background radiation in the magnetar magnetosphere has been calculated. It has been shown that the resonant mechanism under consideration is inefficient for the production of cold dark mass.

hep-ph↗
arXiv2008

Electromagnetic Processes In Strongly Magnetized Plasma

The electromagnetic processes of Compton scattering and photon splitting/merging are investigated in the presence of strongly magnetized electron-positron plasma. The influence of these processes on the radiation transfer in the astrophysical environment is studied. In particular, the contribution of the processes under consideration in coefficients of the transfer equation is calculated. We show the importance of photon splitting/merging contribution and taking into account of photon dispersion and wave function renormalization in strong magnetic field and plasma.

hep-ph↗
arXiv2008

Influence of the photon - neutrino processes on magnetar cooling

The photon-neutrino processes $γe^{\pm} \to e^{\pm} ν\bar ν$, $γ\to ν\bar ν$ and $γγ\to ν\bar ν$ are investigated in the presence of a strongly magnetized and dense electron-positron plasma. The amplitudes of the reactions $γe^{\pm} \to e^{\pm} ν\bar ν$ and $γγ\to ν\bar ν$ are obtained. In the case of a cold degenerate plasma contributions of the considering processes to neutrino emissivity are calculated. It is shown that contribution of the process $γγ\to ν\bar ν$ to neutrino emissivity is supressed in comparision with the contributions of the processes $γe^{\pm} \to e^{\pm} ν\bar ν$ and $γ\to ν\bar ν$. The constraint on the magnetic field strength in the magnetar outer crust is obtained.

astro-ph↗
arXiv2006

The Compton effect in a strongly magnetized plasma

The process of Compton scattering $γe^{\pm} \to γe^{\pm}$ in a strongly magnetized medium of arbitrary temperature and zeroth chemical potential was considered. The analytical expressions for the partial cross section in the small concentration limit of the electron-positron plasma are obtained. The numerical estimations for the partial probabilities of this process are presented by taking into account the photon dispersion in a strong magnetic field and charge-symmetric plasma of arbitrary temperature. The comparision of the scattering probability with photon splitting in a plasma was investigated. The astrophysical applications of the obtaining results are considered.

hep-ph↗
arXiv2003

General amplitude of the n - vertex one-loop process in a strong magnetic field

A general analysis of the n-vertex loop amplitude in a strong magnetic field is performed, based on the asymptotic form of the electron propagator in the field. As an example, the photon-neutrino processes are considered, where one vertex in the amplitude is of a general type, and the other vertices are of the vector type. It is shown, that for odd numbers of vertices only the SV_1 ... V_{n-1} amplitude grows linearly with the magnetic field strength, while for even numbers of vertices the linear growth takes place only in the amplitudes PV_1 ... V_{n-1}, VV_1 ... V_{n-1} and AV_1 ... V_{n-1}. The general expressions for the amplitudes of the processes gamma gamma -> nu bar nu (in the framework of the model with the effective nu nu e e - coupling of a scalar type) and gamma gamma -> nu bar nu gamma (in the framework of the Standard Model) for arbitrary energies of particles are obtained. A comparison with existing results is performed.

hep-ph↗