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"Efremov, A V"
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Semi-inclusive deep-inelastic scattering in Wandzura-Wilczek-type approximation
A
bstract
We present the complete cross-section for the production of unpolarized hadrons in semi-inclusive deep-inelastic scattering up to power-suppressed
O
1
/
Q
2
terms in the Wandzura-Wilczek-type approximation, which consists in systematically assuming that
q
¯
g
q
-terms are much smaller than
q
¯
q
-correlators. We compute all twist-2 and twist-3 structure functions and the corresponding asymmetries, and discuss the applicability of the Wandzura-Wilczek-type approximations on the basis of available data. We make predictions that can be tested by data from COMPASS, HERMES, Jefferson Lab, and the future Electron-Ion Collider. The results of this paper can be readily used for phenomenology and for event generators, and will help to improve the description of semi-inclusive deep-inelastic processes in terms of transverse momentum dependent parton distribution functions and fragmentation functions beyond the leading twist.
Journal Article
How to measure the linear polarization of gluons in unpolarized proton using the heavy-quark pair production
In recent papers [1, 2], two new ways have been proposed to probe the linear polarization of gluons in unpolarized proton: using the azimuthal asymmetries and Callan-Gross ratio in heavy-quark pair leptoproduction, lN → l′QQ̅X . In this talk, we discuss in details the sensitivity of the QCD predictions for the azimuthal cos φ and cos 2 φ asymmetries to the contribution of linearly polarized gluons inside unpolarized proton, where the azimuth φ is the angle between the lepton scattering plane ( l, l ′) and the heavy quark production plane ( N, Q ). Our analysis shows that the azimuthal distributions under consideration vary from 0 to 1 depending on the value of the gluonic counterpart of the Boer- Mulders function,$h_{1}^{ \\bot g}$ . We conclude that the cos φ and cos 2 φ asymmetries in heavy-quark pair production in DIS processes are predicted to be large in wide kinematic ranges and sensitive to the contribution of linearly polarized gluons.
Journal Article
Semi-inclusive deep inelastic scattering in Wandzura-Wilczek-type approximation
We present the complete cross-section for the production of unpolarized hadrons in semi-inclusive deep-inelastic scattering up to power-suppressed O (1/ Q 2 ) terms in the Wandzura–Wilczek-type approximation which consists in systematically assuming that q̅gq –terms are much smaller than q̅q –correlators. We compute all twist-2 and twist-3 structure functions and the corresponding asymmetries, and discuss the applicability of the Wandzura–Wilczek-type approximations on the basis of available data. We make predictions that can be tested by data from Jefferson Lab, COMPASS, HERMES, and the future Electron-Ion Collider. The results of this paper can be readily used for phenomenology and for event generators, and will help to improve our understanding of the TMD theory beyond leading twist. For more details see [1] or slides of Anatoly Efremov talk at https://indico.jinr.ru/getFile.py/access?contribId=25&sessionId=15&resId=0&materialId=slides&confId=433 .
Journal Article
Modeling and study of properties of surfaces equidistant to a sphere and a plane
In the present paper geometric locus of points (GLP) equidistant to a sphere and a plane is considered; the properties of the acquired surfaces are studied. Four possible cases of mutual location of a sphere and a plane are considered: the plane passing through the center of the sphere, the plane intersecting the sphere, the plane tangent to the sphere and the plane passing outside the sphere. GLP equidistant to a sphere and a plane constitutes two co-axial co-focused paraboloids of revolution. General properties of the acquired paraboloids were studied: the location of foci, vertices, axis and directing planes, distance between the sphere center and the vertices, the distance between the vertices. GLP for each case of mutual location of a plane and a sphere constitutes: in case one passes through the center of other, two co-axial co-focused oppositely directed paraboloids of revolution symmetrical with respect to the given plane; in case they intersect each other, two co-axial co-focused oppositely directed non-symmetrical paraboloids; in case they are tangent to each other, a paraboloid and a straight line passing through the tangency point; in case they have no common points, a pair of co-axial co-focused mutually directed paraboloids of revolution.
Journal Article
Application of vectorized algorithms for solving problems of continuum mechanics
The paper discusses the possibilities of constructing vectorized algorithms for solving problems of continuum mechanics, as well as the specialties of their software implementation in the MATLAB. These algorithms, on the one hand, widely use MATLAB functions designed to treat vectors and sparse matrixes, and on the other hand, are distinguished by high efficiency and counting speed.
Journal Article
Integration of the inverse dynamics with a reference model technique, and its application for the improvement of the helicopter flying qualities
The application of inverse dynamics for the improvement of flying qualities is considered. It is shown that the use of the inverse dynamics in the control loop suppresses the dynamics of the aircraft considerably, leaving only the dynamics of the integral in almost the entire frequency range. The inverse dynamics however could not help in case of atmospheric disturbances or modeling uncertainties. A new scheme using a reference model and its inverse was presented to counter these effects. The results of the mathematical modeling showed that the inverse dynamics allow to improve the tracking performances and all other parameters of the pilot-aircraft system compared to the controller synthesized with feedback gains only. These results were confirmed using ground based simulation. These simulations showed that the use of the inverse dynamics based technique allowed to decrease the variance of error up to 60% during a tracking compensation task. The simulations also showed to that the addition of the reference model and its inverse proved to be able to reduce or suppress atmospheric turbulence, couplings between different control channels and effects of modeling uncertainties, while improving the tracking accuracy and decreasing the pilot workload, thus enhancing the flying qualities of the helicopter.
Journal Article
Correlation of Phase Composition, Structure, and Mechanical Properties of Natural Basalt Continuous Fibers
This paper presents a study of the influence of basalt rocks’ phase composition, acidity modulus, and structural parameter NBO/T on the tensile strength and elastic modulus of basalt continuous fibers (BCFs) derived from them. A series of BCF samples based on 14 different basalt deposits was obtained under equal conditions. The tensile strength and elastic modulus of the BCFs from different deposits vary in the ranges of 1495–3380 MPa and 58.2–78.7 GPa, respectively. Using the original method of quantitative phase analysis based on the Rietveld method, the phase compositions of the 14 deposits were defined. All deposits can be used to obtain BCFs. In the studied natural rocks, the main component is tectosilicates; the mass content of framework aluminosilicates is in the range of 16.5–3.3 mass percent. The second main component is inosilicates; the mass content of chain aluminosilicates is in the range of 6.0–58.0 mass percent. The correlations among phase composition, acidity modulus, ratio of non-bridging oxygens to tetrahedral cations, tensile strength, and elastic modulus of the BCFs from the 14 different basalt deposits were calculated. There were strong positive correlation between tectosilicate minerals mass content and elastic modulus [Pearson correlation coefficient (PCC) of 0.7] and strong negative correlation between content of chain and layered aluminosilicates and elastic modulus (PCC of − 0.74).
Journal Article
Probing the linearly polarized gluons in unpolarized proton with heavy-quark pair production
We consider the azimuthal cos φ and cos 2φ distributions and the Callan-Gross ratio R = dσL/dσT in heavy-quark pair electroproduction, lN→ l ′ Q Q ¯ X , as probes of linearly polarized gluons in unpolarized nucleons. Our analysis shows that the azimuthal asymmetries and Callan-Gross ratio are predicted to be large and very sensitive to the contribution of the gluonic counterpart of the Boer-Mulders function, h 1 ⊥g , describing the linear polarization of gluons inside unpolarized nucleon. In particular, the maximum values of the azimuthal distributions vary from 0 to 1 depending on h 1 ⊥g . We conclude that future measurements of these quantities at the proposed EIC and LHeC colliders could clarify in details the proton spin decomposition puzzle.
Journal Article
Power Generation at PAO Koks
The history of power generation at PAO Koks is outlined.
Journal Article