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A. V. Kuznetsov

Publications and source records attributed to A. V. Kuznetsov.

67 records · Page 4Linked to original sources
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↗
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↗
arXiv1998

Photon decay gamma->nu anti-nu in an external magnetic field

The process of the photon decay into the neutrino - antineutrino pair in a magnetic field is investigated. The amplitude and the probability are analysed in the limits of relatively small and strong fields. The probability is suppressed by a factor (G_F m^2_e)^2 as compared with the probability of the pure electromagnetic process gamma -> e- e+. However, the process with neutrinos could play a role of an additional channel of stellar energy-loss.

hep-ph↗
arXiv1997

Neutrino transitions nu -> nu gamma, nu -> nu e+ e- in a strong magnetic field as a possible origin of cosmological gamma-burst

The high energy neutrino transitions with the photon and electron-positron pair creation in a strong magnetic field in the framework of the Standard Model are investigated. The process probabilities and the mean values of the neutrino energy and momentum loss are presented. The asymmetry of outgoing neutrinos, as a possible source of sufficient recoil ``kick'' velocity of a remnant and the emission of e+ e- pairs and gamma-quanta in a ``polar cap'' region of a remnant, as a possible origin of cosmological gamma-burst are discussed.

hep-ph↗
arXiv1997

Creation of photons and electron - positron pairs by a neutrino in a strong magnetic field

The processes of the photon and electron-positron pair production by a neutrino propagating in a strong magnetic field are investigated in the framework of the Standard Model. The process probabilities and the mean values of the neutrino energy and momentum loss are calculated. Possible astrophysical manifestations of the processes considered are briefly analysed.

hep-ph↗
arXiv1995

THREE TYPES OF FERMION MIXING AND POSSIBLE MANIFESTATIONS OF A PATI--SALAM LEPTOQUARK IN THE LOW--ENERGY PROCESSES

I report the recent studies\cite{1,2} on the low--energy manifestations of a minimal extension of the Standard Model based on the quark-lepton symmetry $SU(4)_V \otimes SU(2)_L \otimes G_R$ of the Pati-Salam type. Given this symmetry the third type of mixing in the interactions ot 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. The decays $μ\rightarrow e γ$, $μ\rightarrow e γγ$, and $μ\rightarrow e e \bar e$ via the vector leptoquark are analysed and the specific hierarchy of the decay probabilities $Γ(μ\rightarrow e e \bar e) \gg Γ(μ\rightarrow e γγ) \gg Γ(μ\rightarrow e γ)$ is shown to exist. The upper limits on the branching ratios at a level of $10^{-18}$ for the $μ\rightarrow e γγ$ decay and at a level of $10^{-15}$ for the $μ\rightarrow e e \bar e$ decay are established.

hep-ph↗
arXiv1994

Muon decays with lepton--number violation via vector leptoquark

The decays $μ\rightarrow e γ$, $μ\rightarrow e γγ$, and $μ\rightarrow e e \bar e$ are analysed in the framework of the Pati-Salam type quark-lepton symmetry $SU(4)_V \otimes SU(2)_L \otimes G_R$ where the effects of mixing in the quark-lepton currents are taken into account. It is shown that the $μ\rightarrow e γγ$ and $μ\rightarrow e e \bar e$ decays via the vector leptoquark have not a GIM--type suppression, while the $μ\rightarrow e γ$ decay has. So, the specific hierarchy of the decay probabilities could take place $Γ(μ\rightarrow e e \bar e) \gg Γ(μ\rightarrow e γγ) \gg Γ(μ\rightarrow e γ)$. The existing bounds on the vector leptoquark mass and on the mixing matrix elements, based on the data for the $μe$ conversion in nuclei and for the ratio of the $K_{e 2}$ and $K_{μ2}$ decays allow to set the upper limits on the branching ratios at a level of $10^{-18}$ for the $μ\rightarrow e γγ$ decay and at a level of $10^{-15}$ for the $μ\rightarrow e e \bar e$ decay.

hep-ph↗
arXiv1994

Could Vector Leptoquarks be Rather Light?

A possible Standard Model extension of the Pati-Salam type with a lepton number as the fourth color is reexamined. A new type of mixing in the interaction of the $SU(4)_V$--leptoquark with quarks and leptons is shown to be required. An additional arbitrariness of the mixing parameters could allow to decrease noticeably the lower bound on the leptoquark mass $M_X$ originated from the $π$ and $K$ decays and the $μe$ conversion. The only mixing independent bound emerging from the cosmological limit on the $π^0 \rightarrow ν\barν$ decay width is $M_X > 18~TeV$.

hep-ph↗
arXiv1994

Vector Leptoquarks Could Be Rather Light?

Some low-energy manifestations of a minimal extension of the Standard Model based on the quark-lepton $SU(4)_V \otimes SU(2)_L \otimes G_R$ symmetry of the Pati-Salam type are analysed. Given this symmetry a new type of mixing in the quark-lepton interactions is shown to be required. An additional arbitrariness of the mixing parameters could allow to decrease noticeably the lower bound on the leptoquark mass $M_X$ originated from the $π$ and $K$ decays and the $μe$ conversion. The only mixing independent bound emerging from the cosmological limit on the $π^0 \rightarrow ν\barν$ decay width is $M_X > 18~TeV$.

hep-ph↗