Matching meson resonances to OPE in QCD

We investigate the possible corrections to the linear Regge trajectories for the light-quark meson sector by matching two-point correlators of quark currents to the Operator Product Expansion. We find that the allowed modifications to the linear behavior must decrease rapidly with the principal quantum number. After fitting the lightest states in each channel and certain low-energy constants the whole spectrum for meson masses and residues is obtained in a satisfactory agreement with phenomenology. The perturbative corrections to our results are discussed.Comment: 4 pages, talk given at the First Workshop on Quark Hadron Duality and the Transition to pQCD (June 2005, Frascati, Italy) and at the International Conference on QCD and Hadronic Physics (June 2005, Beijing, China

Parity doubling in particle physics

Parity doubling in excited hadrons is reviewed. Parity degeneracy in hadrons was first experimentally observed 40 years ago. Recently new experimental data on light mesons caused much excitement and renewed interest to the phenomenon, which still remains to be enigmatic. The present retrospective review is an attempt to trace the history of parity doubling phenomenon, thus providing a kind of introduction to the subject. We begin with early approaches of 1960s (Regge theory and dynamical symmetries) and end up with the latest trends (manifestations of broader degeneracies and AdS/QCD). We show the evolution of various ideas about parity doubling. The experimental evidence for this phenomenon is scrutinized in the non-strange sector. Some experiments of 1960s devoted to the search for missing non-strange bosons are re-examined and it is argued that results of these experiments are encouraging from the modern perspective.Comment: Version to appear in Int. J. Mod. Phys. A, 63 pages, 9 figure

Implications of the Crystal Barrel data for meson-baryon symmetries

Making use of numerous resonances discovered by the Crystal Barrel Collaboration we discuss some possible relations between the baryon and meson spectra of resonances composed of the light non-strange quarks. Our goal is to indicate new features that should be reproduced by the realistic dynamical models describing the hadron spectrum in the sector of light quarks.Comment: Completely modified version; to appear in Mod. Phys. Lett.

1/N_c and 1/n preasymptotic corrections to Current-Current correlators

We obtain the corrections in $1/n$ and in $1/\ln n$ ($n$ is the principal quantum number of the bound state) of the decay constants of scalar and pseudoscalar currents in two and four dimensions in the large $N_c$. We obtain them from the operator product expansion provided a model for the large $n$ mass spectrum is given. In the two-dimensional case the spectrum is known and the corrections obtained in this paper are model independent. We confirm these results by confronting them with the numerical solution of the 't Hooft model. We also consider a model at finite $N_c$ and obtain the associated decay constants that are consistent with perturbation theory. This example shows that that the inclusion of perturbative corrections, or finite $N_c$ effects, to the OPE does not constrain the slope of the Regge trajectories, which remain a free parameter for each different channel.Comment: 29 pages, 11 figures. Two references adde

Use of information technology to increase economic efficiency and credibility in public administration in the context of digitization

Purpose: The article analyzes the use of information technologies to increase the level of economic efficiency and trust in public administration in Ukraine. Design/Methodology/Approach: We use the concept of digital management for the purpose of integrated interaction of municipal and state structures with business, civil society institutions and the population. Findings: The conducted research concludes the active digital transformation of public administration in Ukraine. The following trends in the use of information technology are identified: the development of institutional support; the creation of analytical portals for ensuring public control; the level of accountability, transparency, accountability of the activity of civil servants; the implementation of e-government projects; the changing philosophy of development of electronic services. Practical Implications: The concept of state policy in the field of digital infrastructure was developed on the basis of a multi-stakeholder approach according to which the main purpose of the state bodies is to identify, prioritize, harmonize and satisfy the stakeholders. Originality/Value: In this article, we show the level of individual regions in Ukraine where there is uneven implementation and use of e-learning tools management.peer-reviewe

About the possibility of five-dimensional effective theories for low-energy QCD

The AdS/QCD models suggest an interesting idea that the effective theory of low-energy QCD may be formulated as a 5-dimensional field theory in the weak coupling regime in which the fifth coordinate plays a role of inverse energy scale. Taking the point of view that this is just an efficient parametrization of the non-perturbative dynamics of strong interactions, we discuss on a qualitative level an alternative possibility for a simpler 5-dimensional parametrization of main phenomena in the low-energy QCD. We propose to interpret the effect of chiral symmetry breaking as an effective appearance of compactified extra dimension with the radius of the order of inverse scale of chiral symmetry breaking. Following some heuristic arguments two dual scenarios for the emergence of the excited light mesons are introduced: In the first scenario, the meson resonances are interpreted as the effects of Kaluza-Klein excitations of quarks inside mesons, in the second one, as the formation of gluon strings wound around the compactified dimension an appropriate number of times. Matching of these scenarios permits to express the slope of radial Regge trajectories through the order parameters of the chiral symmetry breaking, with the compactification radius being excluded. This example shows qualitatively that the extra dimension may play an auxiliary role providing a short way for deriving new relations.Comment: 11 pages, accepted by Eur. Phys. J.

Motivation of youth participation in volunteering

В статье приводятся результаты авторского социологического исследования, посвященного изучению особенностей мотивации участия молодежи в волонтерском движении. Особое внимание при этом уделяется исследованию олимпийского волонтерства.The article presents the results of author’s sociological research devoted to the study of motivation of youth participation in volunteer movement. Special attention is paid to the study of оlympic volunteering.Работа выполнена в рамках инициативной НИР ЯрГУ № ВИП: 003

Weinberg like sum rules revisited

The generalized Weinberg sum rules containing the difference of isovector vector and axial-vector spectral functions saturated by both finite and infinite number of narrow resonances are considered. We summarize the status of these sum rules and analyze their overall agreement with phenomenological Lagrangians, low-energy relations, parity doubling, hadron string models, and experimental data.Comment: 31 pages, noticed misprints are corrected, references are added, and other minor corrections are mad