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Related papers: Small-$x$ Helicity Evolution: an Operator Treatmen…

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Relating the high-energy dipole description of deep-inelastic scattering to the standard light-ray operator formulation at finite Bjorken $x_B$ is essential for connecting the small-$x$ framework to the usual partonic description. I…

High Energy Physics - Phenomenology · Physics 2026-04-08 Giovanni Antonio Chirilli

We solve a unified integral equation to obtain the $x, Q_T$ and $Q$ dependence of the gluon distribution of a proton in the small $x$ regime; where $x$ and $Q_T$ are the longitudinal momentum fraction and the transverse momentum of the…

High Energy Physics - Phenomenology · Physics 2014-11-17 J. Kwiecinski , A. D. Martin , P. J. Sutton

We investigate the Q^2 evolution of parton distributions at small x values, obtained in the case of flat initial conditions. The contributions of twist-two and (renormalon-type) higher-twist operators of the Wilson operator product…

High Energy Physics - Phenomenology · Physics 2007-05-23 A. V. Kotikov , G. Parente

Using the recently obtained Pgq splitting function we extend the low x evolution equation for gluons to account for contributions originating from quark-to-gluon splitting. In order to write down a consistent equation we resum virtual…

High Energy Physics - Phenomenology · Physics 2016-12-21 M. Hentschinski , A. Kusina , K. Kutak

We investigate the renormalization of a class of gauge-invariant nonlocal quark bilinear operators, including a finite-length Wilson-line (called Wilson-line operators). The matrix elements of these operators are involved in the recent…

High Energy Physics - Lattice · Physics 2018-11-09 Gregoris Spanoudes , Haralambos Panagopoulos

We calculate single-logarithmic corrections to the small-$x$ flavor-singlet helicity evolution equations derived recently in the double-logarithmic approximation. The new single-logarithmic part of the evolution kernel sums up powers of…

High Energy Physics - Phenomenology · Physics 2022-04-08 Yuri V. Kovchegov , Andrey Tarasov , Yossathorn Tawabutr

We determine the small Bjorken $x$ asymptotics of the quark and gluon orbital angular momentum (OAM) distributions in the proton in the double-logarithmic approximation (DLA), which resums powers of $\alpha_s \ln^2 (1/x)$ with $\alpha_s$…

High Energy Physics - Phenomenology · Physics 2019-05-01 Yuri V. Kovchegov

In this paper, we investigate the small-$x$ behavior of the flavor-singlet, leading-twist quark Transverse Momentum Dependent parton distribution functions (TMDs) using the Light-Cone Operator Treatment. This formalism allows us to express…

High Energy Physics - Phenomenology · Physics 2026-01-15 M. Gabriel Santiago , Daniel Adamiak , Yossathorn Tawabutr

We discuss the spin structure of the proton in a light-cone treatment of the chiral quark model. Based on the fact that the quark helicity ($\Delta q$) measured in polarized deep inelastic scattering experiments is actually the quark spin…

High Energy Physics - Phenomenology · Physics 2012-07-03 Xinyu Zhang , Bo-Qiang Ma

We develop simple analytic representations of the polarized quark and gluon distributions in the nucleon at low $Q^2$ which incorporate general constraints obtained from the requirements of color coherence of gluon couplings at $x \sim 0$…

High Energy Physics - Phenomenology · Physics 2009-09-25 Stanley J. Brodsky , Matthias Burkardt , Ivan Schmidt

Analysing the asymptotic behaviour of the quark-quark elastic scattering amplitude at high energy and fixed transferred momentum and assuming that gluon is reggeized, we obtain the evolution equation for the gluon Regge trajectory in QCD.…

High Energy Physics - Phenomenology · Physics 2009-10-28 I. A. Korchemskaya , G. P. Korchemsky

We study the transverse momentum dependent (TMD) parton distributions at small-x in a consistent framework that takes into account the TMD evolution and small-x evolution simultaneously. The small-x evolution effects are included by…

High Energy Physics - Phenomenology · Physics 2017-06-28 Bo-Wen Xiao , Feng Yuan , Jian Zhou

By analyzing experimental data on semi-inclusive deep inelastic scattering off longitudinally polarized targets, we extract the transverse momentum dependence of the quark helicity distribution, i.e., the difference between the…

High Energy Physics - Phenomenology · Physics 2024-09-27 Alessandro Bacchetta , Alessia Bongallino , Matteo Cerutti , Marco Radici , Lorenzo Rossi

We discuss perturbative evolution of the polarized structure function g_1 in the (x,Q^2) plane, with special regard to the small-x region. We determine g_1 in terms of polarized quark and gluon distributions using coefficient functions to…

High Energy Physics - Phenomenology · Physics 2009-10-28 R. D. Ball , S. Forte , G. Ridolfi

We study the Q^2 evolution of parton distributions at small x values, obtained in the case of flat initial conditions. The contributions of twist-two and (renormalon-type) higher-twist operators of the Wilson operator product expansion are…

High Energy Physics - Phenomenology · Physics 2007-05-23 A. V. Kotikov , G. Parente

We use an s-channel picture of hard hadronic collisions to investigate the parton distribution function for quarks at small momentum fraction x, which corresponds to very high energy scattering. We study the renormalized quark distribution…

High Energy Physics - Phenomenology · Physics 2008-11-26 F. Hautmann , D. E. Soper

The high-energy evolution of Wilson line operators, which at leading order is described by the Balitsky-JIMWLK equations, receives large radiative corrections enhanced by single and double collinear logarithms at next-to-leading order and…

High Energy Physics - Phenomenology · Physics 2016-09-21 Yoshitaka Hatta , Edmond Iancu

We study the evolution of the small $x$ gluon transverse momentum dependent(TMD) distribution in the dilute limit. The calculation has been carried out in the Ji-Ma-Yuan scheme using a simple quark target model. As expected, we find that…

High Energy Physics - Phenomenology · Physics 2016-07-20 Jian Zhou

We propose a modified Balitsky-Fadin-Kuraev-Lipatov equation from the viewpoint of the resummation technique, which contains an intrinsic dependence on momentum transfer Q, and satisfies the unitarity bound. The idea is to relax the strong…

High Energy Physics - Phenomenology · Physics 2016-09-06 Hsiang-nan Li

We derive the complete Wilson renormalization group equation which governs the evolution of the gluon distribution and other gluonic observables at low $x$ and arbitrary density.

High Energy Physics - Phenomenology · Physics 2008-11-26 Jamal Jalilian-Marian , Alex Kovner , Heribert Weigert