34 research outputs found
Field-induced axion decay in plasma
The axion decay 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
G and at the temperature of order 10 MeV is reduced to s.Comment: 9 pages, latex, 2 PS figures, corrected some typo
The radiative decay of a high energy neutrino in the Coulomb field of a nucleus
In the framework of the Standard Model with lepton mixing the radiative decay
of a neutrino of high () and super-high () energy is investigated in the
Coulomb field of a nucleus. Estimates of the decay probability and ``decay
cross-section'' for neutrinos of these energies in the electric field of a
nucleus permit one to discuss the general possibility of carrying out a
neutrino experiment, subject to the condition of availability in the future of
a beam of neutrinos of these high energies. Such an experiment could give
unique information on mixing angles in the lepton sector of the Standard Model
which would be independent of the specific neutrino masses if only the
threshold factor () was not close to zero. (Published in
Phys.Lett.B 323 (1994) 179).Comment: 5 pages, LaTeX, Yaroslavl, Yaroslavl State University preprint
YARU-HE-93/0
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.Comment: 8 pages, LaTeX, typos fixed, minor modifications, version accepted to
Physics Letters
Axion decay in a strong magnetic field
The axion decay into charged fermion-antifermion pair is
studied in external crossed and magnetic fields. The result we have obtained
can be of use to re-examine the lower limit on the axion mass in case of
possible existence of strong magnetic fields at the early Universe stage.Comment: 6 pages, latex. Amended version, references added, to be published in
Phys.Lett.
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.Comment: 13 pages, LaTeX, 1 EPS figure, submitted to Physics Letters
Electromagnetic Catalysis of the Radiative Decay of the Axion
The radiative decay of the axion is investigated in an
external electromagnetic field in DFSZ model in which axion couples to both
quarks and leptons at tree level. The decay probability is strongly catalyzed
by the external field, namely, the field removes the main suppression caused by
the smallness of the axion mass.Comment: Minor revision, references added, to be published in Phys.Lett.
Photon splitting above the pair creation threshold in a strong magnetic field
The process of photon splitting 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.Comment: 13 pages, 3 figures, LaTeX, uses epsf.sty, numerical error in eq.(11)
corrected, typos fixed, presentation improved, accepted to Physics Letters
Vector Leptoquarks Could Be Rather Light?
Some low-energy manifestations of a minimal extension of the Standard Model
based on the quark-lepton 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 originated from the and decays and the conversion. The only mixing independent bound emerging from the cosmological
limit on the decay width is .Comment: 10 pages, LaTeX, Yaroslavl, Yaroslavl State University preprint
YARU-HE-94/0
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, , , , , 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.Comment: 8 pages, 1 ps figure, LaTeX, uses espcrc2.sty,epsf.sty, based on the
talks presented at the Xth International Baksan School "Particles and
Cosmology", Baksan Valley, Kabardino Balkaria, Russia, April 19-25, 1999 and
the International Workshop "Particles in Astrophysics and Cosmology: From
Theory to Observation", Valencia, Spain, May 3-8, 199
Neutrino-electron processes in a dense magnetized plasma
The neutrino-electron scattering in a dense degenerate magnetized plasma
under the conditions is investigated.
The volume density of the neutrino energy and momentum losses due to this
process are calculated. The results we have obtained demonstrate that plasma in
the presence of an external magnetic field is more transparent for neutrino
than non-magnetized plasma. It is shown that neutrino scattering under
conditions considered does not lead to the neutrino force acting on plasma.Comment: 11 pages, LATEX, to be published in Central European Science Journa