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Related papers: THE GLUON DISTRIBUTION AT SMALL x OBTAINED FROM A …

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We perform analysis of the small x non-linear evolution equation formulated in momentum space supplemented by higher order terms. The equation is defined in wide range of transverse momentum and longitudinal momentum fraction extending…

High Energy Physics - Phenomenology · Physics 2025-06-03 Krzysztof Kutak , Wanchen Li , Anna Stasto , Robert Straka

We propose an improvement of the splitting functions at small x which overcomes the apparent problems encountered by the BFKL approach. We obtain a stable expansion for the x-evolution function chi(M) near M=0 by including in it a sequence…

High Energy Physics - Phenomenology · Physics 2008-11-26 Guido Altarelli , Richard D. Ball , Stefano Forte

This talks examines the effect of angular ordering on the small-x evolution of the unintegrated gluon distribution, and discusses the characteristic function for the CCFM equation.

High Energy Physics - Phenomenology · Physics 2007-05-23 M. Scorletti

We recall the origin of angular ordering of soft parton emission in the region of small $x$ and show that this coherent structure can be detected in associated distributions. For structure functions at small $x$ and at fixed transverse…

High Energy Physics - Phenomenology · Physics 2009-10-28 Giuseppe Marchesini

In this paper we have solved the nonlinear Gribov-Levin-Ryskin-Mueller-Qiu (GLR-MQ) evolution equation for gluon distribution function G(x,Q^2) and studied the effects of the nonlinear GLR-MQ corrections to the Leading Order (LO)…

High Energy Physics - Phenomenology · Physics 2014-02-24 Mayuri Devee , J. K. Sarma

Parton distributions in the small $x$ region are numerically predicted by using a modified DGLAP equation with the GRV-like input distributions. We find that gluon recombination at twist-4 level obviously suppresses the rapid growth of…

High Energy Physics - Phenomenology · Physics 2014-11-17 Wei Zhu , Jian-hong Ruan , Ji-feng Yang , Zhen-qi Shen

We investigate the recently proposed nonlinear equation for the unintegrated gluon distribution function which includes the subleading effects at small $x$. We obtained numerically the solution to this equation in $(x,k)$ space, and also…

High Energy Physics - Phenomenology · Physics 2008-11-26 K. Kutak , A. M. Stasto

Evolution of gluon distribution function from Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) evolution equation in next-to-leading order (NLO) at low-x is presented assuming the Regge behaviour of quarks and gluons at this limit. We…

High Energy Physics - Phenomenology · Physics 2010-03-25 U. Jamil , J. K. Sarma

We study the nuclear shadowing effect in the context of Glauber-Gribov multiple-scattering model and perturbative QCD. We find that at small x, the $Q^2$ evolution of the shadowing is much slower than the DGLAP evolution, due to the…

High Energy Physics - Phenomenology · Physics 2007-05-23 Ina Sarcevic

We revisit the problem of the small Bjorken-$x$ asymptotics of the quark and gluon orbital angular momentum (OAM) distributions in the proton utilizing the revised small-$x$ helicity evolution derived recently. We relate the quark and gluon…

High Energy Physics - Phenomenology · Physics 2024-07-24 Yuri V. Kovchegov , Brandon Manley

In this paper we derive an integral equation for the evolution of unintegrated (longitudinally) polarized quark and gluon parton distributions. The conventional CCFM framework is extended at small x in order to incorporate the QCD…

High Energy Physics - Phenomenology · Physics 2009-11-07 Jan Kwiecinski , Martin Maul

We evaluate the unintegrated gluon distribution of the proton starting from a parametrization of the color dipole cross section including DGLAP evolution and saturation effects. To this end, we perform the Fourier-Bessel transform of…

High Energy Physics - Phenomenology · Physics 2022-12-14 Agnieszka Łuszczak , Marta Łuszczak , Wolfgang Schäfer

The gluon distribution is dominated by the hard pomeron at small $x$ and all $Q^2$, with no soft-pomeron contribution. This describes well not only the DGLAP evolution of the hard-pomeron part of $F_2(x,Q^2)$, but also charm photoproduction…

High Energy Physics - Phenomenology · Physics 2014-11-17 A Donnachie , P V Landshoff

The $k_{\perp}$ dependent gluon distribution is calculated accounting for the resummation of small~$x$ effects due to the Lipatov equation. It is represented by a convolution of a gluon density in the collinear limit and a universal…

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

In this work we aim to gain qualitative insight on the far-from-equilibrium behavior of the gluon plasma produced in the early stages of a heavy-ion collision. It was recently discovered arXiv:1810.10554 that the distribution functions of…

High Energy Physics - Phenomenology · Physics 2022-06-08 Jasmine Brewer , Bruno Scheihing-Hitschfeld , Yi Yin

The solution of non-linear evolution equations for dense nuclear gluon density has been suggested as one of the relevant mechanisms of pA and AA collisions at collider energies. Here we study a simple parameterization for the unintegrated…

High Energy Physics - Phenomenology · Physics 2010-02-11 M. A. Betemps , M. V. T. Machado

In recent papers, we have established the existence of gauge-invariant decomposition of nucleon spin, each term of which can be related to known high-energy deep-inelastic-scattering observables. A subtlety remains, however, for the…

High Energy Physics - Phenomenology · Physics 2011-08-12 Masashi Wakamatsu

We present some simple methods to find gluon distribution from analysis of deuteron F_{2} structure function data at moderately low-x. Here we use the leading order(LO) Altarelli -Parisi(AP) evolution equation and New Muon Collaboration…

High Energy Physics - Phenomenology · Physics 2014-11-17 J. K. Sarma , G. A. Ahmed

We determine the small-$x$ asymptotics of the gluon helicity distribution in a proton at leading order in perturbative QCD at large $N_c$. To achieve this, we begin by evaluating the dipole gluon helicity TMD at small $x$. In the process we…

Nuclear Theory · Physics 2018-08-31 Yuri V. Kovchegov , Daniel Pitonyak , Matthew D. Sievert

WE propose a new unified evolution equation for parton distribution functions appropriate for both large and small Bjorken x. Compared with the Ciafaloni- Catani-Fiorani-Marchesini equation, the cancellation of soft poles between virtual…

High Energy Physics - Phenomenology · Physics 2007-05-23 Jyh-Liong Lim