A vortex model for transport in the polar stratosphere

A semi-empirical model based on a Gaussian vorticity distribution was developed for determining eddy diffusivity and wind transport distributions in the polar stratosphere. The model uses as input data pressure surface heights measured at periods of the year when the stratospheric polar vortex exhibits nearly circular patterns around the pole. The components of the polar wind velocities that result from a Prandtl eddy viscosity distribution are found to be in general agreement with those obtained by other investigators

On kaonic deuterium. Quantum field theoretic and relativistic covariant approach

We study kaonic deuterium, the bound K^-d state A_(K d). Within a quantum field theoretic and relativistic covariant approach we derive the energy level displacement of the ground state of kaonic deuterium in terms of the amplitude of K^-d scattering for arbitrary relative momenta. Near threshold our formula reduces to the well-known DGBT formula. The S-wave amplitude of K^-d scattering near threshold is defined by the resonances Lambda(1405), Sigma(1750) and a smooth elastic background, and the inelastic channels K^- d -> NY and K^- d -> NY pion, with Y = Sigma^(+/-), Sigma^0 and Lambda^0, where the final-state interactions play an important role. The Ericson-Weise formula for the S-wave scattering length of K^-d scattering is derived. The total width of the energy level of the ground state of kaonic deuterium is estimated using the theoretical predictions of the partial widths of the two-body decays A_(Kd) -> NY and experimental data on the rates of the NY-pair production in the reactions K^-d -> NY. We obtain Gamma_{1s} = (630 +/-100) eV. For the shift of the energy level of the ground state of kaonic deuterium we predict epsilon_(1s) = (353 +/-60)eV.Comment: 73 pages,10 figures, Latex, We have slightly corrected the contribution of the double scattering. The change of the S-wave scattering length of K^-d scattering does not go beyond the theoretical uncertainty, which is about 18

The role of nucleon recoil in low-energy antikaon-deuteron scattering

The effect of the nucleon recoil for antikaon-deuteron scattering is investigated in the framework of effective field theory. In particular, we concentrate on the calculation of the nucleon recoil effect for the double-scattering process. It is shown that the leading correction to the static term that emerges at order xi^{1/2} with xi=M_K/m_N vanishes due to a complete cancellation of individually large contributions. The resulting recoil effect in this process is found to be of order of 10-15% as compared to the static term. We also briefly discuss the application of the method in the calculations of the multiple-scattering diagrams.Comment: 16 pages, 4 figure

Monitoring of all hydrogen isotopologues at tritium laboratory Karlsruhe using Raman spectroscopy

We have recorded Raman spectra for all hydrogen isotopologues, using a CW Nd:YVO4 laser (5 W output power at 532 nm) and a high-throughput (f/1.8) spectrograph coupled to a Peltier-cooled (200 K) CCD-array detector (512x2048 pixels). A (static) gas cell was used in all measurements. We investigated (i) “pure” fillings of the homonuclear isotopologues H2, D2, and T2; (ii) equilibrated binary fillings of H2+D2, H2+T2, and D2+T2, thus providing the heteronuclear isotopologues HD, HT and DT in a controlled manner; and (iii) general mixtures containing all isotopologues at varying concentration levels. Cell fillings within the total pressure range 13–985 mbar were studied, in order to determine the dynamic range of the Raman system and the detection limits for all isotopologues. Spectra were recorded for an accumulation period of 1000 s. The preliminary data evaluation was based on simple peak-height analysis of the ro-vibrational Q1-branches, yielding 3σ measurement sensitivities of 5x10–3, 7x10–3, and 25x10–3 mbar for the tritium-containing isotopologues T2, DT, and HT, respectively. These three isotopologues are the relevant ones for the KATRIN experiment and in the ITER fusion fuel cycle. While the measurements reported here were carried out with static-gas fillings, the cells are also ready for use with flowing-gas samples