Unitary Structure of the QCD Sum Rules and KYN and KY\Xi Couplings

New relations between QCD Borel sum rules for strong coupling constants of K-mesons to baryons are derived. It is shown that starting from the sum rule for the coupling constants $g_{\pi\Sigma\Sigma}$ and $g_{\pi\Sigma\Lambda}$ it is straightforward to obtain corresponding sum rules for the $g_{K Y N}$, $g_{K Y \Xi}$ couplings, $Y=\Sigma,\Lambda$.Comment: 7 pages, 2 tables, International Workshop on Quantum Chromodynamics:Theory and Experiment, QCD@Work-2005, Coversano(Bari, Italy), 16-20 June, 200

Polarization of the electron and positron produced in combined Coulomb and strong laser fields

The process of $e^+e^-$ production in the superposition of a Coulomb and a strong laser field is considered. The pair production rate integrated over the momentum and summed over the spin projections of one of the particles is derived exactly in the parameters of the laser field and in the Born approximation with respect to the Coulomb field. The case of a monochromatic circularly polarized laser field is considered in detail. A very compact analytical expression of the pair production rate and its dependence on the polarization of one of the created particles is obtained in the quasiclassical approximation for the experimentally relevant case of an undercritical laser field. As a result, the polarization of the created electron (positron) is derived.Comment: 16 pages, no figure

The Gailitis-Damburg oscillations in the three-body e−e+pˉe^-e^+\bar{p} system

We study the near threshold behavior of cross sections of low-energy antiproton scattering off the ground and excited states of positronium with zero total orbital momentum $L=0$. In our computational experiment, the existence of singularities called the Gailitis-Damburg oscillations above the thresholds of excited states of positronium and antihydrogen atoms is confirmed. In the future the obtained results can be useful for developing proposals for improving the conditions of experiments with antimatter.Comment: 7 pages, 4 figure