On the mistake in the implementation of the minimal model of the dual parameterization and resulting inability to describe the high-energy DVCS data

We correct the mistaken claim made in \cite{Guzey:2005ec,Guzey:2006xi} that the minimal model of the dual parameterization of nucleon generalized parton distributions (GPDs) gives a good, essentially model-independent description of high-energy data on deeply virtual Compton scattering (DVCS). In the implementation of the dual parameterization in \cite{Guzey:2005ec,Guzey:2006xi}, the numerical prefactor of two in front of the DVCS amplitude was missing. We show that the corrected minimal model of the dual parameterization significantly overestimates the HERA data (H1 and ZEUS) on the DVCS cross section.Comment: 8 pages, 1 figur

Nuclear physics with a medium-energy Electron-Ion Collider

A polarized ep/eA collider (Electron-Ion Collider, or EIC) with variable center-of-mass energy sqrt(s) ~ 20-70 GeV and a luminosity ~ 10^{34} cm^{-2} s^{-1} would be uniquely suited to address several outstanding questions of Quantum Chromodynamics (QCD) and the microscopic structure of hadrons and nuclei: (i) the three-dimensional structure of the nucleon in QCD (sea quark and gluon spatial distributions, orbital motion, polarization, correlations); (ii) the fundamental color fields in nuclei (nuclear parton densities, shadowing, coherence effects, color transparency); (iii) the conversion of color charge to hadrons (fragmentation, parton propagation through matter, in-medium jets). We briefly review the conceptual aspects of these questions and the measurements that would address them, emphasizing the qualitatively new information that could be obtained with the collider. Such a medium-energy EIC could be realized at Jefferson Lab after the 12 GeV Upgrade (MEIC), or at Brookhaven National Lab as the low-energy stage of eRHIC.Comment: 9 pages, 5 figures. Mini-review compiled in preparation for the MEIC Conceptual Design Report, Jefferson Lab (2011

Complete analysis of spin structure function g1 of He-3

We present a comprehensive analysis of the nuclear effects important in DIS on polarized He-3 over a wide range of Bjorken x, 10^{-4} \leq x \leq 0.8. Effects relevant for the extraction of the neutron spin structure function, g1^n, from the He-3 data are emphasized.Comment: 30 pages, 6 figures, LaTe

Production of Theta+ in gamma + D -> Lambda + Theta+ and gamma + D -> Sigma + Theta+ reactions

The gamma + D -> Lambda + Theta+ and gamma + D -> Sigma + Theta+ reactions can be used to determine the width of Theta+ almost model-independently. We calculate the differential cross sections of the gamma +D -> Lambda + Theta+, gamma + D -> Sigma + Theta+ and relevant background reactions in the photon energy range 1.2 < E_{\gamma} < 2.6 GeV. We determine the most favorable kinematic conditions and observables for the experimental studies of Theta+ in the considered processes. We argue that a comparison of the gamma + D -> Lambda + Theta+ and gamma + D -> Sigma + Theta+ cross sections should unambiguously determine isospin of Theta+.Comment: 22 pages, 9 figures. Final published versio

Non-singlet structure function of the 3He-3H system and divergence of the Gottfried integral

We study shadowing and antishadowing corrections to the flavor non-singlet structure function F_2(3He)-F_2(3H) and show that the difference between the one-particle density distributions of 3He and 3H plays an important role at very small x. We find that the flavor non-singlet structure function in these mirror nuclei is enhanced at small x by nuclear shadowing, which increases the nuclear Gottfried integral, integrated from 10^{-4} to 1, by 11-36 %. When integrated from zero, the Gottfried integral is divergent for these mirror nuclei. It seems likely that, as a consequence of charge symmetry breaking, this may also apply to the proton-neutron system.Comment: 29 pages, 6 figures, RevTe

The dual parameterization of the proton generalized parton distribution functions H and E and description of the DVCS cross sections and asymmetries

We develop the minimal model of a new leading order parameterization of GPDs introduced by Shuvaev and Polyakov. The model for GPDs H and E is formulated in terms of the forward quark distributions, the Gegenbauer moments of the D-term and the forward limit of the GPD E. The model is designed primarely for small and medium-size values of x_B, x_B \leq 0.2. We examined two different models of the t-dependence of the GPDs: The factorized exponential model and the non-factorized Regge-motivated model. Using our model, we successfully described the DVCS cross section measured by H1 and ZEUS, the moments of the beam-spin A_{LU}^{\sin \phi}, beam-charge A_{C}^{\cos \phi} and transversely-polarized target A_{UT}^{\sin \phi \cos \phi} DVCS asymmetries measured by HERMES and A_{LU}^{\sin \phi} measured by CLAS. The data on A_{C}^{\cos \phi} prefers the Regge-motivated model of the t-dependence of the GPDs. The data on A_{UT}^{\sin \phi \cos \phi} indicates that the u and d quarks carry only a small fraction of the proton total angular momentum.Comment: 33 pages, 11 figure

Nuclear shadowing in inclusive and tagged deuteron structure functions and extraction of F_2^p-F_2^n at small x from electron-deuteron collider data

We review predictions of the theory of leading twist nuclear shadowing for inclusive unpolarized and polarized deuteron structure functions F_2^D, g_1^D and b_1^D and for the tagged deuteron structure function F_2^D(x,Q^2,\vec{p}). We analyze the possibility to extract the neutron structure function F_2^n from electron-deuteron data and demonstrate that an account of leading twist nuclear shadowing leads to large corrections for the extraction of F_2^n from the future deuteron collider data both in the inclusive and in the tagged structure function modes. We suggest several strategies to address the extraction of F_2^n and to measure at the same time the effect of nuclear shadowing via the measurement of the distortion of the proton spectator spectrum in the semi-inclusive e D \to e^{\prime}NX process. We address the issue of the final state interactions in the e D \to e^{\prime}NX process and examine how they affect the extraction of F_2^n.Comment: 19 pages, 7 figures. Published in Mod. Phys. Lett.

Nondiagonal Parton Distributions in the Leading Logarithmic Approximation

In this paper we make predictions for nondiagonal parton distributions in a proton in the LLA. We calculate the DGLAP-type evolution kernels in the LLA, solve the nondiagonal GLAP evolution equations with a modified version of the CTEQ-package and comment on the range of applicability of the LLA in the asymmetric regime. We show that the nondiagonal gluon distribution $g(x_{1},x_{2},t,\mu^2)$ can be well approximated at small $x$ by the conventional gluon density $xG(x,\mu^2)$. Keywords: Hard Diffractive Scattering, Nondiagonal distributions, EvolutionComment: 20 pages, RevTex. Final version with updated figures. Published in Phys. Lett.

Methodological and analytical provision of region monitoring

The article reflects methodological and applied aspects of the quality and completeness of information provided to the monitoring taking into account the level of spatial aggregation. The authors suggest an algorithm on forming informational blocks of monitoring on the region level which allows to implement the functions of the given analytical tool. Furthermore, the article provides the reasons for integrating information within the united methodological and legal area of Russian public statistics in order to form the representative database for regional monitoring and analysis.peer-reviewe

Medium modifications of the bound nucleon GPDs and incoherent DVCS on nuclear targets

We study incoherent DVCS on He-4 in the He-4(e.e\u27gamma p)X reaction, which probes possible medium-modifications of the bound nucleon GPDs and elastic form factors. Assuming that the bound nucleon GPDs are modified in proportion to the corresponding bound nucleon elastic form factors, as predicted in the quark-meson coupling model, we develop an approach to calculate various incoherent nuclear DVCS observables. As an example, we compute the beam-spin DVCS asymmetry, and predict the x(B)- and t-dependence of the ratio of the bound to free proton asymmetries, A(LU)(p*)(phi)/A(LU)(p)(phi). We find that the deviation of AP(LU)(p*)(phi)/A(LU)(p)(phi) from unity is as Much as similar to 6%. (C) 2009 Elsevier B.V. All rights reserved