3,342,086 research outputs found
Anomalies in radiation-collisional kinetics of Rydberg atoms induced by the effects of dynamical chaos and the double Stark resonance
Radiative and collisional constants of excited atoms contain the matrix
elements of the dipole transitions and when they are blocked one can expect
occurring a number of interesting phenomena in radiation-collisional kinetics.
In recent astrophysical studies of IR emission spectra it was revealed a gap in
the radiation emitted by Rydberg atoms () with values of the principal
quantum number of . Under the presence of external electric fields
a rearrangement of emission spectra is possible to associate with
manifestations of the Stark effect. The threshold for electric field ionization
of is V/cm for states with . This means that
the emission of with is effectively blocked for such fields. In
the region of lower electric field intensities the double Stark resonance (or
F\"{o}rster resonance) becomes a key player. On this basis it is established
the fact that the static magnetic or electric fields may strongly affect the
radiative constants of optical transitions in the vicinity of the F\"{o}ster
resonance resulting, for instance, in an order of magnitude reduction of the
intensity in some lines. Then, it is shown in this work that in the atmospheres
of celestial objects lifetimes of comparatively long-lived states and
intensities of corresponding radiative transitions can be associated with the
effects of dynamic chaos via collisional ionization. The F\"{o}ster resonance
allows us to manipulate the random walk of the Rydberg electron () in the
manifold of quantum levels and hence change the excitation energies of ,
which lead to anomalies in the IR spectra.Comment: in press Advances in Space Researc
Degenerate Neutrinos and CP Violation
We have studied mixing and masses of three left handed Majorana neutrinos in
the model, which assumes exactly degenerate neutrino masses at some "neutrino
unification" scale. Such a simple theoretical ansatz naturally leads to
quasidegenerate neutrinos. The neutrino mass splittings induced by
renormalization effects. In the model we found that the parameters of the
neutrino physics (neutrino mass spectrum, mixing angles and CP violation
phases) are strongly intercorrelated to each other. From these correlations we
got strong bounds on the parameters which could be checked in the oscillation
experiments.Comment: 5 pages, latex, presented at CAPP200
Electromagnetic form factor of pion in the field theory inspired approach
A new formula for the pion form factor F_pi is proposed which takes into
account the pseudoscalar meson loops and the mixing among rho(770), rho(1450),
and rho(1700). The expression possesses correct analytical properties and can
be used in both timelike and spacelike kinematical regions. The comparison is
made with the existing experimental data on F_pi collected by the detectors
SND, CMD-2, KLOE, and BaBaR restricted to energies below 1 GeV. A good
description of all four data sets is obtained. In the spacelike region, upon
substituting the resonance parameters found in the timelike one, the formula
gives F_pi, in agreement with the measurements of the NA7 Collaboration.Comment: 12 pages, 8 figures. Text rearranged. Clarifying remarks and
references adde
Transition Radiation by Standard Model Neutrinos at an Interface
We discuss the transition radiation process at an
interface of two media. The medium fulfills the dual purpose of inducing an
effective neutrino-photon vertex and of modifying the photon dispersion
relation. The transition radiation occurs when at least one of those quantities
have different values in different media. We present a result for the
probability of the transition radiation which is both accurate and analytic.
For MeV neutrino crossing polyethylene-vacuum interface the
transition radiation probability is about and the energy intensity
(deposition) is about eV. At the surface of the neutron stars the
transition radiation probability may be . Our result on three
orders of magnitude is larger than the results of previous calculations.}Comment: invited talk, to appear in the proceedings of the XLVIth Rencontres
de Moriond EW 201
Discrete transformation for matrix 3-waves problem in three dimensional space
Discrete transformation for 3- waves problem is constructed in explicit form.
Generalization of this system on the matrix case in three dimensional space
together with corresponding discrete transformation is presented also.Comment: LaTeX, 16 page
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