Baryon octet distribution amplitudes in Wandzura-Wilczek approximation

We study higher twist distribution amplitudes for the SU_F(3) baryon octet. We identify independent functions for all baryons in the isospin symmetry limit and calculate the Wandzura-Wilczek contributions to the twist-4 and 5 distributions amplitudes.Comment: 7 page

Strong and radiative decays of the Ds0*(2317) meson in the DK-molecule picture

We consider a possible interpretation of the new charm-strange meson Ds0*(2317) as a hadronic molecule - a bound state of D and K mesons. Using an effective Lagrangian approach we calculate the strong Ds0* to Ds pi0 and radiative Ds0* to Ds* gamma decays. A new impact related to the DK molecular structure of the Ds0*(2317) meson is that the presence of u(d) quarks in the D and K mesons gives rise to a direct strong isospin-violating transition Ds0* to Ds pi0 in addition to the decay mechanism induced by eta-pi0 mixing considered previously. We show that the direct transition dominates over the eta-pi0 mixing transition in the Ds0* to Ds pi0 decay. Our results for the partial decay widths are consistent with previous calculations.Comment: 22 pages, 4 figures, accepted for publication in Phys. Rev.

Ds0*(2317) and Ds1(2460) mesons in two-body B-meson decays

We analyze the branching ratios of B to D(*) + Ds0*(Ds1) decays using the factorization hypothesis. The B to D(*) transition form factors are taken from a model-independent analysis done by Caprini, Lellouch and Neubert based on heavy quark spin symmetry and dispersive constraints, including short-distance and power corrections. The leptonic decay constants fDs0* and fDs1 are calculated assuming a molecular structure for the Ds0* and Ds1 mesons. The calculated branching ratios of B-meson two-body decays are compared with experimental data and other theoretical results.Comment: 12 pages, 2 figure

Theory and phenomenology of helicity amplitudes for high energy exclusive leptoproduction of the rho-meson

We review here two approaches to describe hard leptoproduction of transversally polarized rho-meson, based on recent calculation of the gamma*T -> rhoT impact factor up to twist 3 accuracy in the collinear factorization frame, including 2- and 3- particles Fock-states. The first approach uses a model of the unintegrated gluon density (the proton impact factor) which allows a comparison of our predictions with H1 and ZEUS data for the ratios of helicity amplitudes T(gamma*T -> rhoT)/T(gamma*L -> rhoL) and T(gamma*T -> rhoL)/T(gamma*L -> rhoL). In the second approach, we transform the gamma*T -> rhoT impact factor into the impact parameter space. We show that the transformed amplitude factorizes according to conventional dipole picture. We shortly discuss a way to implement the nucleon saturation effects in our approach.Comment: 5 pages, 2 figures, to appear in the proceedings of 6th International Conference on Quarks and Nuclear Physics (QNP 2012), Palaiseau, France, April 16-20, 201

High Energy exclusive Leptoproduction of the rho-meson: Theory and Phenomenology

We describe the hard leptoproduction of transversally polarized rho-meson, up to twist 3 accuracy, including 2- and 3- particles Fock-states, in the HERA kinematics of high center-of-mass energy. We first build a model based on a simple approach to the unintegrated gluon density (the parton impact factor) that we compare with H1 and ZEUS data for the ratios of helicity amplitudes T(gamma*T -> rhoT)/T(gamma*L -> rhoL) and T(gamma*T -> rhoL)/T(gamma*L -> rhoL) and get a good description of the data. We also show how saturation effects can be included in this model by extending the dipole representation of the scattering amplitude in coordinate space up to twist 3.Comment: 4 pages, 3 figures, to appear in the proceedings of 20th International Workshop on Deep-Inelastic Scattering and Related Subjects (DIS 2012), Bonn, Germany, 26-30 March 201

Real Compton Scattering via Color Dipoles

We study photoabsorption reaction and real Compton scattering (RCS) within the color dipole model. We rely on a photon wave function derived in the instanton vacuum model, and on the energy dependent phenomenological elastic dipole amplitude. Data for the photoabsorption cross section at high energies agree with our parameter free calculations. We also provide predictions for the differential RCS cross section. Although no data for small angle Compton scattering are available so far, this process can be measured in ultra-peripheral hadronic and nuclear collisions at the LHC.Comment: 9 pages, 4 figures. Some statements clarified, bibliographic inaccuracy correcte

A phenomenological study of helicity amplitudes of high energy exclusive leptoproduction of the rho meson

We apply a previously developed scheme to consistently include the twist-3 distribution amplitudes for transversely polarized rho meson in order to evaluate, in the framework of kT factorization, the helicity amplitudes for exclusive leptoproduction of a light vector meson, at leading order in alphaS. We compare our results with high energy experimental data for the ratios of helicity amplitudes T11/T00 and T01/T00 and get a good description of the data.Comment: 20 pages, 11 figures, published version in PR

Methods For Evaluation Of The Education Quality In Higher Education Institutions

The article aims to disclose the essence of the “education quality” concept, to study the international approaches and concepts of the higher education quality evaluation, to analyze specific methods and tools within one of the approaches. Establishing education quality assessment necessitates choosing the teaching personnel of higher educational institution, as well as a target group of students and independent experts in the field of organization of the educational process, on a distance basis particularly. Monitoring requires using such methods as interviews, surveys, questionnaires, and similar. The results were processed according to the authors’ algorithm allowing to calculate the quality of education. The authors’ interpretation of the concept of “education quality” is proposed. Given the insufficient study of the topic of distance education in the domestic scientific discourse, authors’ attention to this problem is an important contribution to study of the issue of distance education. The methods used to evaluate the education quality in higher education institutions at the international level are an integral element in the development of the educational space, although they cause certain controversy and criticism. The authors advise to select the methods for evaluating the educational process quality with account of the specific evaluation stage and purpose

Model study of generalized parton distributions with helicity flip

Generalized parton distributions with helicity flip are studied in the quark sector, within a simple version of the MIT bag model, assuming an SU(6) wave function for the proton target. In the framework under scrutiny it turns out that only the generalized transversity distribution, H_T^q, is non vanishing. For this quantity, the forward limit is properly recovered and numerical results are found to underestimate recent lattice data for its first moment. Positivity bounds recently proposed are fulfilled by the obtained distribution. The relevance of the analysis for the planning of measurements of the quark generalized transversity is addressed.Comment: 15 pages, 4 figures; shortened version accepted for publication in Phys. Rev.