Microscopic derivation of the pion coupling to heavy-light mesons

The Goldberger--Treiman relation for heavy--light systems is derived in the context of a quark model. As a paradigmatic example, the case of ${\bar D}\to {\bar D}' \pi$ is studied in detail. The fundamental role played by the pion two-component wave function, in the context of the Salpeter equation, is emphasized.Comment: 6 pages, 2 figures, version to appear in Phys. Rev.

Chiral symmetry restoration in excited hadrons, quantum fluctuations, and quasiclassics

In this paper, we discuss the transition to the semiclassical regime in excited hadrons, and consequently, the restoration of chiral symmetry for these states. We use a generalised Nambu-Jona-Lasinio model with the interaction between quarks in the form of the instantaneous Lorentz-vector confining potential. This model is known to provide spontaneous breaking of chiral symmetry in the vacuum via the standard selfenergy loops for valence quarks. It has been shown recently that the effective single-quark potential is of the Lorentz-scalar nature, for the low-lying hadrons, while, for the high-lying states, it becomes a pure Lorentz vector and hence the model exhibits the restoration of chiral symmetry. We demonstrate explicitly the quantum nature of chiral symmetry breaking, the absence of chiral symmetry breaking in the classical limit as well as the transition to the semiclassical regime for excited states, where the effect of chiral symmetry breaking becomes only a small correction to the classical contributions.Comment: RevTeX4, 20 pages, 4 Postscript figures, uses epsfig.sty, typos correcte

Subjective well-being as a result of the realization of projects of the elderly's involvement into the social life

The paper analyses the subjective well-being and Successful Aging concepts. Unbiased analysis of such conditions is rather problematic by virtue of such facts as time-specific emotional state, climate of residence, culture, current developments and etc. The study concludes that there is no correlation between subjective well-being and economic health or objective socioeconomic factors. The subjective well-being is influenced in most cases by subjective factors: one’s health status satisfaction, financial situation, the level of self-reliance or independence, family interaction and other human relations. But the main factor is the recognition of their mission by the elderly which places the faith and hope in their future modeling. Two categories of the elderly are sorted out for the study: the involved and noninvolved in social activity. The research concludes that any formal or informal activity of the elderly is one of the main factors of the successful aging. Pursuit of activities is uncharacteristic for noninvolved in social activity elderly people. The paper analyses the projects organized and implemented by not only the elderly people themselves but also state and social structures.. Conducted analysis indicates that the level of subjective well-being of the two categories of the elderly is increasing as the result of these projects realization

QCD string in light-light and heavy-light mesons

The spectra of light-light and heavy-light mesons are calculated within the framework of the QCD string model, which is derived from QCD in the Wilson loop approach. Special attention is payed to the proper string dynamics that allows us to reproduce the straight-line Regge trajectories with the inverse slope being 2\pi\sigma for light-light and twice as small for heavy-light mesons. We use the model of the rotating QCD string with quarks at the ends to calculate the masses of several light-light mesons lying on the lowest Regge trajectories and compare them with the experimental data as well as with the predictions of other models. The masses of several low-lying orbitally and radially excited heavy--light states in the D, D_s, B, and B_s meson spectra are calculated in the einbein (auxiliary) field approach, which has proven to be rather accurate in various calculations for relativistic systems. The results for the spectra are compared with the experimental and recent lattice data. It is demonstrated that an account of the proper string dynamics encoded in the so-called string correction to the interquark interaction leads to an extra negative contribution to the masses of orbitally excited states that resolves the problem of the identification of the D(2637) state recently claimed by the DELPHI Collaboration. For the heavy-light system we extract the constants \bar\Lambda, \lambda_1, and \lambda_2 used in Heavy Quark Effective Theory (HQET) and find good agreement with the results of other approaches.Comment: RevTeX, 42 pages, 7 tables, 7 EPS figures, uses epsfig.sty, typos corrected, to appear in Phys.Rev.

QCD string and the Lorentz nature of confinement

We address the question of the Lorentz nature of the effective long-range interquark interaction generated by the QCD string with quarks at the ends. Studying the Dyson-Schwinger equation for a heavy-light quark-antiquark system, we demonstrate explicitly how a Lorentz-scalar interaction appears in the Diraclike equation for the light quark, as a consequence of chiral symmetry breaking. We argue that the effective interquark interaction in the Hamiltonian of the QCD string with quarks at the ends stems from this effective scalar interaction.Comment: LaTeX2e, 5 pages, uses jetpl.cls (included), to appear in JETP Let

Hamiltonian approach to the bound state problem in QCD_2

Bosonization of the two-dimensional QCD in the large N_C limit is performed in the framework of Hamiltonian approach in the Coulomb gauge. The generalized Bogoliubov transformation is applied to diagonalize the Hamiltonian in the bosonic sector of the theory, and the composite operators creating/annihilating bosons are obtained in terms of dressed quark operators. The bound state equation is reconstructed as a result of the generalized Bogoliubov transformation, and the form of its massless solution, chiral pion, is found explicitly. Chiral properties of the theory are discussed.Comment: 9 pages, LaTeX2

Mineral Concentrates As a Factor of the Khibiny Apatite-Nepheline Ores Efficiency Improvement

Apatite-nepheline ores of the Khibiny deposits contain the largest phosphorus-bearing resources in the world, and, at the same time, they contain associated valuable components in the rock-forming minerals — apatite, nepheline, sphene and titanium magnetite. Intensive development of the Khibiny deposits with production of only apatite concentrate and a small part of nepheline concentrate resulted in the accumulation of over 1.0 billion tons of wastes in tailing storage facilities and dumps during 90 years of JSC Apatit operation. The possibility of increasing the efficiency of the use of the main concentrates of apatite-nepheline ores of the Khibiny deposits and wastes for their processing is considered through the use of technological developments of the FRC KSC RAS, JSC RIFI and JSC Apatit to obtain traditional and new target products. A fundamentally new approach to the problem of sustainable use of natural resources is focused on establishment of the whole production chain in the region, from mining and processing operations to manufacturers of final high technology products (rare-earth products, welding and construction materials, coloring agents and other materials). They also determine the level of industrial technical progress. Keywords: Khibiny apatite-nepheline ores, mineral raw materials, extraction and processing, new material

What can radiative decays of the X(3872) teach us about its nature?

Starting from the hypothesis that the X(3872) is a $D\bar D^*$ molecule, we discuss the radiative decays of the X(3872) into $\gamma J/\psi$ and $\gamma\psi'$ from an effective field theory point of view. We show that radiative decays are very weakly sensitive to the long-range structure of the X(3872). In particular, contrary to earlier claims, we argue that the experimentally determined ratio of the mentioned branching fractions is not in conflict with a wave function of the X(3872) that is dominated by the $D\bar D^*$ hadronic molecular component.Comment: LaTeX2e, 10 pages, 1 figure, 2 tables, version ot appear in Phys.Lett.

A short distance quark-antiquark potential

Leading terms of the static quark-antiquark potential in the background perturbation theory are reviewed, including perturbative, nonperturbative and interference ones. The potential is shown to describe lattice data at short quark-antiquark separations with a good accuracy.Comment: 4 pages, 2 figures, talk at the NPD-2002 Conference, December 2-6, ITEP, Moscow, references update