arXiv subjects

N. V. Mikheev

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

At least 19 recordsLinked to original sources

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↗

arXiv2012

The third type of fermion mixing and indirect limits on the Pati-Salam leptoquark mass

The low-energy manifestations of a minimal extension of the electroweak standard model based on the quark-lepton symmetry $SU(4)_V \otimes SU(2)_L \otimes G_R$ of the Pati-Salam type are analyzed. Given this symmetry the third type of mixing in the interactions of the $SU(4)_V$ leptoquarks with quarks and leptons is shown to be required. An additional arbitrariness of the mixing parameters could allow, in principle, to decrease noticeably the indirect lower bound on the vector leptoquark mass originated from the low-energy rare processes, strongly suppressed in the standard model.

hep-ph↗

arXiv2012

The third type of fermion mixing in the lepton and quark interactions with leptoquarks

The low-energy manifestations of a minimal extension of the electroweak standard model based on the quark-lepton symmetry $SU(4)_V \otimes SU(2)_L \otimes G_R$ of the Pati--Salam type are analyzed. Given this symmetry the third type of mixing in the interactions of the $SU(4)_V$ leptoquarks with quarks and leptons is shown to be required. An additional arbitrariness of the mixing parameters could allow, in principle, to decrease noticeably the lower bound on the vector leptoquark mass originated from the low-energy rare processes, strongly suppressed in the standard model.

hep-ph↗

arXiv2011

Ultra-high energy neutrino dispersion in plasma and radiative transition $ν_L \to ν_R + γ$

Qualitative analysis of additional energy of neutrino and antineutrino in plasma is performed. A general expression for the neutrino self-energy operator is obtained in the case of ultra-high energies when the local limit of the weak interaction is not valid. The neutrino and antineutrino additional energy in plasma is calculated using the dependence of the $W$ and $Z$--boson propagators on the momentum transferred. The kinematical region for the neutrino radiative transition (the so-called "neutrino spin light") is established for some important astrophysical cases. For high energy neutrino and antineutrino, dominating transition channels in plasma, $ν_e + e^+ \to W^+$, $\barν_e + e^- \to W^-$ and $\barν_{\ell} + ν_{\ell} \to Z$, are indicated.

hep-ph↗

arXiv2011

Neutrino-triggered asymmetric magnetorotational mechanism for pulsar natal kick

The sterile neutrino mechanisms for natal neutron star kicks are reanalyzed. It is shown that the magnetic field strengths needed for obtaining the observable values of kicks were underestimated essentially. Another mechanism with standard neutrinos is discussed where the outgoing neutrino flux in a supernova explosion with a strong toroidal magnetic field generation causes the field redistribution in "upper" and "lower" hemispheres of the supernova envelope. The resulting magnetic field pressure asymmetry causes the pulsar natal kick.

hep-ph↗

arXiv2010

Reexamination of a Bound on the Dirac Neutrino Magnetic Moment from the Supernova Neutrino Luminosity

We investigate the neutrino helicity-flip process under supernova core conditions, where the left-handed neutrinos being produced can be converted into right-handed neutrinos sterile with respect to the weak interaction due to the interaction of magnetic moments with plasma electrons and protons. Instead of the uniform ball model for the SN core used in previous analyses, realistic models for radial distributions and time evolution of physical parameters in the supernova core are considered. We have obtained new upper limits on the Dirac neutrino magnetic moment averaged over flavours and time from the condition that the influence of the right-handed neutrino emission on the total cooling time scale should be limited.

astro-ph.HE↗

arXiv2010

Neutrino magnetic moment in a magnetized plasma

The contribution of a magnetized plasma to the neutrino magnetic moment is calculated. It is shown that only part of the additional neutrino energy in magnetized plasma connecting with its spin and magnetic field strength defines the neutrino magnetic moment. It is found that the presence of magnetized plasma does not lead to the considerable increase of the neutrino magnetic moment in contrast to the results presented in literature previously.

hep-ph↗

arXiv2010

A decay of the ultra-high-energy neutrino $ν_e \to e^- W^+$ in a magnetic field and its influence on the shape of the neutrino spectrum

The width of the neutrino decay into the electron and $W$ boson in a strong external magnetic field is obtained from the imaginary part of the neutrino self-energy. This result corrects the formulae existing in the literature. The mean free path of an ultra-high energy neutrino in a strong magnetic field is calculated. An energy cutoff for neutrinos propagating in a strong field is defined.

hep-ph↗

arXiv2010

Dirac neutrino magnetic moment and a possible time evolution of the neutrino signal from a supernova

We analyze the influence of neutrino helicity conversion, $ν_L \to ν_R$, on the neutrino flux from a supernova caused by the interaction of the Dirac neutrino magnetic moment with a magnetic field. We show that if the neutrino has a magnetic moment in the interval $10^{-13} \, μ_{\rm B} < μ_ν< 10^{-12} \, μ_{\rm B}$ and provided that a magnetic field of $\sim 10^{13} - 10^{14}$ G exists in the supernova envelope, a peculiar kind of time evolution of the neutrino signal from the supernova caused by the resonance transition $ν_L \to ν_R$ in the magnetic field of the envelope can appear. If a magnetar with a poloidal magnetic field is formed in a supernova explosion, then the neutrino signal could have a pulsating behavior, i.e., a kind of a neutrino pulsar could be observed, when it rotates around an axis that does not coincide with its magnetic moment and when the orientation of its rotation axis is favourable for our observation.

astro-ph.HE↗

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↗

arXiv2010

High energy neutrino absorption by W production in a strong magnetic field

An influence of a strong external magnetic field on the neutrino self-energy operator is investigated. The width of the neutrino decay into the electron and W boson, and the mean free path of an ultra-high energy neutrino in a strong magnetic field are calculated. A kind of energy cutoff for neutrinos propagating in a strong field is defined.

hep-ph↗

arXiv2009

Reexamination of a Bound on the Dirac Neutrino Magnetic Moment from the Supernova Neutrino Luminosity

The neutrino helicity-flip process under the conditions of the supernova core is reinvestigated. Instead of the uniform ball model for the SN core used in previous analyses, realistic models for radial distributions and time evolution of physical parameters in the SN core are considered. A new upper bound on the Dirac neutrino magnetic moment is obtained from the limit on the supernova core luminosity for nu_R emission.

hep-ph↗

arXiv2009

Dirac-Neutrino Magnetic Moment and the Dynamics of a Supernova Explosion

The double conversion of the neutrino helicity $ν_L \to ν_R \to ν_L$ has been analyzed for supernova conditions, where the first stage is due to the interaction of the neutrino magnetic moment with plasma electrons and protons in the supernova core, and the second stage, due to the resonance spin flip of the neutrino in the magnetic field of the supernova envelope. It is shown that, in the presence of the neutrino magnetic moment in the range $10^{-13} μ_{\rm B} < μ_ν< 10^{-12} μ_{\rm B}$ and a magnetic field of $\sim 10^{13}$ G between the neutrinosphere and the shock-stagnation region, an additional energy of about $10^{51}$ erg, which is sufficient for a supernova explosion, can be injected into this region during a typical shock-stagnation time.

hep-ph↗

arXiv2008

Neutrino dispersion in magnetized plasma

The neutrino dispersion in the charge symmetric magnetized plasma is investigated. We have studied the plasma contribution into the additional energy of neutrino and obtained the simple expression for it. We consider in detail the neutrino self-energy under physical conditions of weak field, moderate field and strong field limits. It is shown that our result for neutrino dispersion in moderate magnetic field differ substantially from the previous one in the literature.

hep-ph↗

arXiv2008

Fermion dispersion in axion medium

The interaction of a fermion with the dense axion medium is investigated for the purpose of finding an axion medium effect on the fermion dispersion. It is shown that axion medium influence on the fermion dispersion under astrophysical conditions is negligible small if the correct Lagrangian of the axion-fermion interaction is used.

hep-ph↗

arXiv2008

Plasma induced fermion spin-flip conversion $f_L \to f_R + γ$

The fermion spin-flip conversion $f_L \to f_R + γ$ is considered, caused by the difference of the additional energies of the electroweak origin, acquired by left- and right-handed fermions (neutrino, electron) in medium. An accurate taking account of the fermion and photon dispersion in medium is shown to be important.

hep-ph↗

arXiv2008

Dirac neutrino magnetic moment and the shock wave revival in a supernova explosion

The process of the two-step conversion of the neutrino helicity, $ν_L \to ν_R \to ν_L$, is analysed in the supernova conditions, where the first stage is realized due to the interaction of the neutrino magnetic moment with the plasma electrons and protons in the supernova core. The second stage is caused by the neutrino resonant spin-flip in a magnetic field of the supernova envelope. Given the neutrino magnetic moment within the interval $10^{-13} μ_{\rm B} < μ_ν< 10^{-12} μ_{\rm B}$, and with the existence of the magnetic field at the scale $\sim 10^{13}$ G between the neutrinosphere and the shock-wave stagnation region, it is shown that an additional energy of the order of $10^{51}$ erg can be injected into this region during the typical time of the shock-wave stagnation. This energy could be sufficient for stumulation of the damped shock wave.

hep-ph↗

arXiv2007

Plasma induced neutrino spin flip via the neutrino magnetic moment

The neutrino spin flip radiative conversion processes nu_L -> nu_R + gamma^* and nu_L + gamma^* -> nu_R in medium are considered. It is shown in part that an analysis of the so-called spin light of neutrino without a complete taking account of both the neutrino and the photon dispersion in medium is physically inconsistent.

hep-ph↗