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N. V. Mikheev

Publications and source records attributed to N. V. Mikheev.

At least 55 records · Page 3Linked to original sources
arXiv2001

Familon emission by dense magnetized plasma

Emission of a familon caused by the processes $e^- \to e^- + ϕ$, $ e^- \to μ^- + ϕ$ in dense magnetized plasma is investigated in the model in which a familon have both direct and no direct coupling to leptons via plasmon. The process probabilities and the integral familon action on plasma are calculated. It is shown that the $ P$ odd interference phenomenon in the process $e^- \to μ^- + ϕ$ leads to the familon force acting on plasma along the magnetic field.

hep-ph↗
arXiv2001

Photon Damping Caused by Electron-Positron Pair Production in a Strong Magnetic Field

Damping of an electromagnetic wave in a strong magnetic field is analyzed in the kinematic region near the threshold of electron-positron pair production. Damping of the electromagnetic field is shown to be noticeably nonexponential in this region. The resulting width of the photon $γ\to e^+ e^-$ decay is considerably smaller than previously known results.

hep-ph↗
arXiv2001

Neutrino Scattering in a Magnetic Field

Motivated by the evidence for a finite neutrino mass we examine anew the interaction of neutrinos in a magnetic field. We present the rate for radiative scattering for both massless and massive neutrinos in the standard model and give the corresponding numerical estimates. We also consider the effects arising from a possible neutrino magnetic moment.

hep-ph↗
arXiv2000

Neutrino-electron processes in a dense maqnetized plasma

The neutrino-electron processes in a dense strongly degenerate magnetized plasma are analyzed in the framework of the Standard Model. The total probability and the mean values of the neutrino energy and momentum losses are calculated. It is shown that neutrino scattering on the excited electrons with Landau level number conservation dominates under the conditions "mu^2 > eB >> mu T" but does not give a contribution into the neutrino force acting on plasma along the magnetic field.

hep-ph↗
arXiv2000

Compton-like interaction of massive neutrinos with virtual photons

The amplitude of a Compton-like process nu_i gamma^* -> nu_j gamma^* with virtual photons is calculated in the standard GWS theory with lepton mixing. The contribution of this process to the high energy neutrino scattering on the nucleus with single photon radiation nu N -> nu N gamma is discussed. The bremsspectrum and the total cross-section are estimated in the leading log approximation.

hep-ph↗
arXiv2000

Radiative neutrino transition $ν\to νγ$ in strongly magnetized plasma

The influence of strongly magnetized electron-positron plasma on the radiative neutrino transition $\nng$ is investigated. The probability and mean losses of the neutrino energy and momentum are calculated taking account of the photon dispersion and large radiative corrections near the resonance. It is shown that the combined effect of plasma and strong magnetic field decreases the probability and mean values of the neutrino energy and momentum loss in comparison with these values obtained in pure magnetic field.

hep-ph↗
arXiv2000

Mass Shift of Axion in Magnetic Field

A mass-shift of the axion propagating in an external constant homogenious magnetic field is calculated. The contributions via an electron loop and a virtual photon are examined. It is shown that the virtual photon contribution dominates substantially over the electron-loop one. Under the conditions of the early Universe the electron-loop contribution to the massless axion mass-shift is equal to zero while the virtual photon contribution is finite and can be of order of the recent restrictions on the axion mass.

hep-ph↗
arXiv1999

Neutrino - electron processes in a strong magnetic field and plasma

The total set of the neutrino - electron processes in a presence of both components of an active medium, hot dense plasma and strong magnetic field, is investigated for the first time. The contribution of the processes $νe^- \to νe^-$, $νe^+ \to νe^+$, $ν\to νe^- e^+$, $νe^- e^+ \to ν$ is shown to dominate and not to depend on the chemical potential of electron-positron gas. Relatively simple expressions for the probability and mean losses of the neutrino energy and momentum are obtained, which are suitable for a quantitative analysis.

hep-ph↗
arXiv1999

Plasma influence on the neutrino - electron processes in a strong magnetic field

An influence of the magnetized electron - positron plasma on the absorption and loss of the energy and momentum in a process of neutrino propagation is investigated. A total contribution of all crossed processes, $ν\to νe^- e^+$, $νe^- \to νe^-$, $νe^+ \to νe^+$, $νe^- e^+ \to ν$, is found for the first time, which appears not to depend on the chemical potential of electron-positron gas. Relatively simple expressions for the probability and mean losses of the neutrino energy and momentum are obtained, which are suitable for a quantitative analysis.

hep-ph↗
arXiv1999

Axion in an External Electromagnetic Field

We investigate the effective interaction of a pseudoscalar particle with two photons in an external electromagnetic field in the general case of all external particles being off the mass shell. This interaction is used to study the radiative decay $a \to γγ$ of the axion, a pseudoscalar particle associated with the Peccei-Quinn symmetry, and the crossing channel of photon splitting $γ\to γa$. It is shown that the external field removes the suppression associated with the smallness of the axion mass and so leads to the strong catalysis of these processes. The field-induced axion emission by photon is analyzed as one more possible source of energy losses by astrophysical objects.

hep-ph↗
arXiv1999

Axion Decay of a Photon in an External Electromagnetic Field

An interaction of a pseudoscalar particle with two photons induced by an external electromagnetic field is used to study the photon decay $γ\to γa$ where a is a pseudoscalar particle associated with the Peccei-Quinn U(1) symmetry. The field-induced axion emission by photon is analyzed as a possible source of energy losses by astrophysical objects.

hep-ph↗
arXiv1999

Field-induced axion decay $a \to e^+ e^-$ in plasma

The axion decay $a \to e^+ e^-$ is investigated in the presence of a plasma and an external magnetic field. The results demonstrate a strong catalyzing influence of medium. The axion lifetime in the magnetic field of order $10^{15}$ G and at the temperature of order 10 MeV is reduced to $10^4$ s.

hep-ph↗
arXiv1998

Field-induced axion decay $a \to e^+ e^-$ via plasmon

The axion decay $a \to e^+ e^-$ via a plasmon is investigated in an external magnetic field. The results we have obtained demonstrate a strong catalyzing influence of the field as the axion lifetime in the magnetic field of order $10^{15}$ G and at temperature of order 10 MeV is reduced to $10^4$ sec.

hep-ph↗
arXiv1998

Field-induced axion emission via process $e^+ e^- \to a$ in plasma

The annihilation into axion $e^+ e^- \to a$ is investigated in a plasma and an external magnetic field. This process via a plasmon intermediate state has a resonant character at a particular energy of the emitted axion. The emissivity by $e^+ e^- \to a$ is compared with the axion cyclotron emissivity.

hep-ph↗
arXiv1998

The transitions gamma gamma -> nu bar nu and gamma -> gamma gamma in a strong magnetic field

The photon-neutrino process gamma gamma -> nu bar nu and photon splitting are considered in a strong magnetic field. The partial polarization amplitudes are calculated within the standard model in the limit of a strong field. The amplitudes do not depend on the field strength in this limit. Using the vector parts of the amplitudes, the process of the photon splitting gamma -> gamma gamma is investigated both below and above the pair creation threshold. The splitting probabilities are calculated taking account of the photon dispersion and large radiative corrections near the resonance.

hep-ph↗
arXiv1998

Photon splitting above the pair creation threshold in a strong magnetic field

The process of photon splitting $γ\to γγ$ in a strong magnetic field is investigated both below and above the pair creation threshold. Contrary to the statement by Baier et al., the ``allowed'' channel $\alw$ is shown not to be a comprehensive description of splitting in the strong field because the ``forbidden'' channel $\frb$ is also essential. The partial amplitudes and the splitting probabilities are calculated taking account of the photon dispersion and large radiative corrections near the resonance.

hep-ph↗