Strong decays of radially excited mesons in a chiral approach

We study radial excitations of pseudoscalar and vector (q bar q) mesons within a chiral approach. We derive a general form for a chiral Lagrangian describing processes involving excited pseudoscalar and vector mesons. The parameters of the chiral Lagrangian are fitted using data and previous calculations in the framework of the 3P0 model. Finite-width effects are examined and predictions for mesons previously not discussed are given. Available experimental data is analyzed whenever possible. Possible hints for exotic mesons and open interpretation-issues are discussed.Comment: 16 page

Electronic and atomic kinetics in solids irradiated with free-electron lasers or swift-heavy ions

In this brief review we discuss the transient processes in solids under irradiation with femtosecond X-ray free-electron-laser (FEL) pulses and swift-heavy ions (SHI). Both kinds of irradiation produce highly excited electrons in a target on extremely short timescales. Transfer of the excess electronic energy into the lattice may lead to observable target modifications such as phase transitions and damage formation. Transient kinetics of material excitation and relaxation under FEL or SHI irradiation are comparatively discussed. The same origin for the electronic and atomic relaxation in both cases is demonstrated. Differences in these kinetics introduced by the geometrical effects ({\mu}m-size of a laser spot vs nm-size of an ion track) and initial irradiation (photoabsorption vs an ion impact) are analyzed. The basic mechanisms of electron transport and electron-lattice coupling are addressed. Appropriate models and their limitations are presented. Possibilities of thermal and nonthermal melting of materials under FEL and SHI irradiation are discussed

NJL interaction derived from QCD: vector and axial-vector mesons

In previous works effective non-local $SU(2)\times SU(2)$ NJL model was derived in the framework of the fundamental QCD. All the parameters of the model are expressed through QCD parameters: current light quark mass $m_0$ and average non-perturbative $\alpha_s$. The results for scalar and pseudo-scalar mesons are in satisfactory agreement to existing data. In the present work the same model without introduction of any additional parameters is applied for a description of masses and strong decay widths of $\rho$- and $a_1$-mesons. The results for both scalar and vector sectors agree with data with only one adjusted parameter $m_0$, with account of average $\alpha_s \simeq 0.415$, which is obtained in a previous work as well.Comment: 19 pages, 2 figures, 1 tabl

Comment on "Exact results for survival probability in the multistate Landau-Zener model"

We correct the proof of Brundobler-Elser formula (BEF) provided in [2004 \textit{J. Phys. B: At. Mol. Opt. Phys.} \textbf{37} 4069] and continued in Appendix of [2005 \textit{J. Phys. B: At. Mol. Opt. Phys.} \textbf{38} 907]. After showing that some changes of variables employed in these articles are used erroneously, we propose an alternative change of variables which solves the problem. In our proof, we reveal the connection between the BEF for a general $N$-level Landau-Zener system and the exactly solvable bow-tie model. The special importance of the diabatic levels with maximum/minimum slope is emphasized throughout.Comment: 10 page

Bogoliubov compensation approach in QCD and in the electroweak theory

We describe application of Bogoliubov compensation principle to calculation of non-perturbative contribution in the electroweak theory and QCD. We obtain unique solutions of compensation equations, which impose strong restrictions on parameters of theories and on functional dependence of corresponding form-factors. We calculate value of running gauge electroweak coupling $\alpha_w(M_W)=0.0374$, that differs from the experimental value less than by 10%. We derive effective Nambu-Jona-Lasinio interaction from fundamental QCD and express its parameters in terms of initial QCD parameters: $\alpha_s$ at low-momenta and current mass of light quarks. This leads to satisfactory description of low-mass hadron physics.Comment: 6 pages, no figures, talk presented at the International Bogolyubov Conference, August 21-27, 2009, Moscow-Dubna, Russi

Production of π0ρ0\pi^0\rho^0 pair in electron-positron annihilation in the Nambu-Jona-Lasinio model

The process $e^+e^- \to \pi^0\rho$ is described in the framework of the expanded NJL model in the energy region from 0.9 GeV to 1.5 GeV. The contribution of intermediate state with vector mesons $\omega(782), \,\,\phi(1020)$, and $\omega'(1420)$, where $\omega'$ is the first radial excitation of $\omega$ - meson was taken into account. Results obtained are in satisfactory agreement with experimental data.Comment: 5 pages, 1 figure, 1 tabl

Theory of Ferromagnetism in Doped Excitonic Condensates

Nesting in a semimetal can lead to an excitonic insulator state with spontaneous coherence between conduction and valence bands and a gap for charged excitations. In this paper we present a theory of the ferromagnetic state that occurs when the density of electrons in the conduction band and holes in the valence band differ. We find an unexpectedly rich doping-field phase diagram and an unusual collective excitation spectrum that includes two gapless collective modes. We predict regions of doping and external field in which phase-separated condensates of electrons and holes with parallel spins and opposing spins coexist.Comment: 5 pages, 3 postscript file

Alloying of Surface Layers of the Fuel Claddings from Sponge Based E110 Alloy to Increase High Temperature Oxidation Resistance

The results of experiments of parts of cladding tubes from sponge based zirconium E110 alloy near-surface layers doping by means of ion-plasma technologies are presented in this paper. Alloying of material by method of pre-deposited Fe, Y, Mo, Al, Mg, Cr films ion mixing is performed on installation ILUR-03 by means of radialAr+ion beam 3-4 keV average energy. State of modified material layer and oxides, grown on the modified samples in argon-water steam mixture at 1200 ∘C studied by scanning electron and ion microscopy methods, X-ray analysis and secondary ion mass spectroscopy. It is shown that treating modes defined contribute to the barrier for oxygen penetration and material oxidation formation near ion-doped surface