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

    Full text link
    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 (RARA) with values of the principal quantum number of n10n\approx10. Under the presence of external electric fields a rearrangement of RARA emission spectra is possible to associate with manifestations of the Stark effect. The threshold for electric field ionization of RARA is E3104E\approx3\cdot10^{4} V/cm for states with n>10n>10. This means that the emission of RARA with n10n\ge10 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 RARA 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 (RERE) in the manifold of quantum levels and hence change the excitation energies of RARA, which lead to anomalies in the IR spectra.Comment: in press Advances in Space Researc

    Degenerate Neutrinos and CP Violation

    Full text link
    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

    Full text link
    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

    Full text link
    We discuss the transition radiation process ννγ\nu \to \nu \gamma 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 Eν=1E_\nu =1MeV neutrino crossing polyethylene-vacuum interface the transition radiation probability is about 103910^{-39} and the energy intensity (deposition) is about 103410^{-34}eV. At the surface of the neutron stars the transition radiation probability may be 1020\sim 10^{-20}. 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

    Full text link
    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
    corecore