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We compute the gluon distribution in deep inelastic scattering at small x by solving numerically the angular ordering evolution equation. The leading order contribution, obtained by neglecting angular ordering, satisfies the BFKL equation.…

High Energy Physics - Phenomenology · Physics 2009-10-30 G. Bottazzi , G. Marchesini , G. P. Salam , M. Scorletti

The implications of the positivity constraint on the presently unknown polarized structure function of the photon, $g_1^{\gamma}(x,Q^2)$, are studied in detail. In particular the non-trivial consequences of this constraint,…

High Energy Physics - Phenomenology · Physics 2009-11-07 M. Gluck , E. Reya , C. Sieg

The nonsinglet spin dependent structure function $g_2(x,Q^2)$ is studied at small x within the double logarithmic approximation of perturbative QCD. Both positive and negative signature contributions are considered, and we find a power-like…

High Energy Physics - Phenomenology · Physics 2009-10-31 J. Bartels , M. G. Ryskin

We study the small $x$ diffractive contribution to the spin--dependent proton structure function $g_1(x)$. We find that the $x\to 0$ behaviour of $ g_1(x)$ has a singular form like $1/(x^\alpha \ln^2(x))$ with $\alpha \sim 0.2-0.3$.

High Energy Physics - Phenomenology · Physics 2008-02-03 S. V. Goloskokov

We consider the interaction of the partonic fluctuation of a scalar ``photon'' with an external color field to calculate the leading and next-to-leading order gluon distribution of the proton following the work done by…

High Energy Physics - Phenomenology · Physics 2009-11-10 H. -J. Pirner , A. I. Shoshi , G. Soyez

The low $x$ limit of deep inelastic electron proton scattering is considered using methods of perturbative QCD. In the first part we investigate the phenomenological consequences of the resummation of leading logarithms in $1/x$ given by…

High Energy Physics - Phenomenology · Physics 2007-05-23 H. Lotter

We investigate the one-gluon-exchange ($\alpha \alpha_s$) corrections to the polarized real photon structure function $g_1^\gamma(x,Q^2)$ in the massive parton model. We employ a technique based on the Cutkosky rules and the reduction of…

High Energy Physics - Phenomenology · Physics 2015-05-30 Norihisa Watanabe , Yuichiro Kiyo , Ken Sasaki

Using an analytical parameterization for the behavior of the x slope of the structure function F_2 at small x in perturbative QCD, at the leading twist approximation of the Wilson operator product expansion, and applying a flat initial…

High Energy Physics - Phenomenology · Physics 2014-11-17 A. V. Kotikov , G. Parente

Using the QCD dipole picture of the hard BFKL Pomeron, we perform a 3 parameter fit analysis of the recent inclusive structure function experimental measurements at small-$x$ and intermediate $Q^2$. As a byproduct, the longitudinal…

High Energy Physics - Phenomenology · Physics 2009-11-10 A. Lengyel , M. V. T. Machado

We examine the behaviour of the polarised structure function data for g_1(x) in the region of small x (~0.01 to 0.1) for the various available targets (proton, neutron and deuteron) with the aim of clarifying what may be safely deduced with…

High Energy Physics - Phenomenology · Physics 2007-05-23 Mehrdad Goshtasbpour , Philip G. Ratcliffe

The perturbative QCD predictions for the small $x$ behaviour of the nucleon structure functions $F_{2,L}(x,Q^2)$ and $g_1(x,Q^2)$ are summarized. The importance of the double logarithmic terms for the small $x$ behaviour of the spin…

High Energy Physics - Phenomenology · Physics 2007-05-23 J. Kwiecinski

In high-energy scattering processes involving two or more hadrons one can measure observables that are sensitive to partonic transverse momentum, which is encoded in so-called transverse momentum dependent (TMD) parton distribution…

High Energy Physics - Phenomenology · Physics 2016-10-27 Tom van Daal

The conventional and linearly polarized Weizs\"acker-Williams gluon distributions at small x are defined from the two-point function of the gluon field in light-cone gauge. They appear in the cross section for dijet production in deep…

High Energy Physics - Phenomenology · Physics 2018-03-14 Adrian Dumitru , Vladimir Skokov

Recent measurements of unpolarised and polarised nucleon structure functions and F_2(gamma) are reviewed. The implications for QCD and the gluon momentum distribution are discussed. The status of the understanding of the total…

High Energy Physics - Experiment · Physics 2007-05-23 Robin Devenish

The behavior of the gluon distribution function and the reduced cross section considered from the proton structure function and its derivatives at low values of $x$. These behaviors studied and compared with the experimental data. These…

High Energy Physics - Phenomenology · Physics 2020-11-17 B. Rezaei , G. R. Boroun

Gluon distribution function at small x is computed using the extended McLerran-Venugopalan model. A lipatov like enhancement is seen as well as a non-trivial transverse momentum dependence which is estimated. It is shown that gluon density…

High Energy Physics - Phenomenology · Physics 2007-05-23 Jamal Jalilian-Marian

The virtual photon structure function $g_1^{\gamma}(x,Q^2,P^2)$, which can be obtained in polarized $e^{+}e^{-}$ colliding-beam experiments, is investigated for $\Lambda^2 \ll P^2 \ll Q^2$, where $-Q^2$ ($-P^2$) is the mass squared of the…

High Energy Physics - Phenomenology · Physics 2007-05-23 Ken Sasaki , Tsuneo Uematsu

The spin-dependent structure functions g_2 (x, Q^2) are investigated within the framework of the chiral quark soliton model. It turns out that the twist-3 part of g_2 (x, Q^2) gives nonnegligible contributions to the total distributions at…

High Energy Physics - Phenomenology · Physics 2009-10-31 M. Wakamatsu

We discuss the large-x behaviour of the splitting functions P_qg and P_gq and of flavour-singlet coefficient functions, such as the gluon contributions C_2,g and C_L,g to the structure functions F_2,L, in massless perturbative QCD. These…

High Energy Physics - Phenomenology · Physics 2010-12-13 A. Vogt , G. Soar , S. Moch , J. A. M. Vermaseren

We fit the reduced cross section for deep-inelastic electron scattering data to a three parameter ln^2 s fit, A + beta ln^2 (s/s_0), where s= [Q^2/x] (1-x) + m^2, and Q^2 is the virtuality of the exchanged photon. Over a wide range in Q^2…

High Energy Physics - Phenomenology · Physics 2008-11-26 M. M. Block , E. L. Berger , C. -I. Tan