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Related papers: The Challenge of Small x

200 papers

The nonlinear Balitsky-Kovchegov equation at small x is solved numerically, incorporating impact parameter dependence. Confinement is modeled by including effective gluon mass in the dipole evolution kernel, which regulates the splitting of…

High Energy Physics - Phenomenology · Physics 2015-05-28 Jeffrey Berger , Anna M. Stasto

We review the parton model and the Regge approach to the QCD description of the deep-inelastic $ep$ scattering at the small Bjorken variable $x$ and demonstrate their relation with the DGLAP and BFKL evolution equations. It is shown, that…

High Energy Physics - Phenomenology · Physics 2014-11-17 L. N. Lipatov

The perturbative QCD predictions concerning deep inelastic scattering at low $x$ are summarized. The theoretical framework based on the leading log $1/x$ resummation and $k_t$ factorization theorem is described and some recent developments…

High Energy Physics - Phenomenology · Physics 2010-03-25 J. Kwiecinski

A computer study is performed to estimate the influence of the small-$k_T$ region in the BFKL evolution equation. We consider the small-x region of the deep inelastic structure function $F_2$ and show that the magnitude of the small-$k_T$…

High Energy Physics - Phenomenology · Physics 2014-11-17 J. Bartels , H. Lotter , M. Vogt

At present there is no correct theory of evolution of F_2(x,Q^2) at small x. It is a mixture of hard and soft pomeron exchange and perturbative QCD very successfully describes the evolution of the hard-pomeron component. This allows the…

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

This paper is devoted to the study of generalised time-fractional evolution equations involving Caputo type derivatives. Using analytical methods and probabilistic arguments we obtain well-posedness results and stochastic representations…

Analysis of PDEs · Mathematics 2022-05-03 M. E. Hernández-Hernández , V. N. Kolokoltsov , L. Toniazzi

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 report an evaluation of subleading eigenvalues and eigenfunctions of the BFKL equation in the color dipole representation with a running gauge coupling. We present an expansion of the small-$x$ proton structure function $F_{2p}(x,Q^2)$…

High Energy Physics - Phenomenology · Physics 2009-10-30 Vladimir R. Zoller

We study coagulation-fragmentation equations inspired by a simple model proposed in fisheries science to explain data for the size distribution of schools of pelagic fish. Although the equations lack detailed balance and admit no…

Analysis of PDEs · Mathematics 2016-11-03 Pierre Degond , Jian-Guo Liu , Robert L. Pego

The HERA data on the proton structure function, $F_2(x,Q^2)$, at very small $x$ and $Q^2$ show the dramatic departure of the logarithmic slope, $\partial F_2/\partial\log Q^2$, from theoretical predictions based on the DGLAP evolution. We…

High Energy Physics - Phenomenology · Physics 2014-11-17 N. N. Nikolaev , V. R. Zoller

The recent progress in color BFKL-Regge phenomenology of small-x DIS on nucleons, pions and photons is reviewed

High Energy Physics - Phenomenology · Physics 2007-05-23 N. N. Nikolaev , V. R. Zoller

We construct an anomalous dimension for small x evolution which goes beyond standard fixed order perturbative evolution by including resummed small x logarithms deduced from the leading order BFKL equation with running coupling.…

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

The consistency of the BFKL equation with the renormalization group is investigated at next-to-leading log-x level.By use of Kt-factorization, it is found that,besides next-to-leading small-x resummation formulae, a leading, x-dependent…

High Energy Physics - Phenomenology · Physics 2009-10-28 Marcello Ciafaloni

We determine an approximate expression for the O(alpha_s^3) contribution chi_2 to the kernel of the BFKL equation, which includes all collinear and anticollinear singular contributions. This is derived using recent results on the relation…

High Energy Physics - Phenomenology · Physics 2010-03-25 Simone Marzani , Richard D. Ball , Pietro Falgari , Stefano Forte

Recent evidence suggests that, at small Bjorken $x$, QCD evolution drives the proton into a state of maximal entanglement. If the evolution kernel is assumed to be conformally invariant -- as is the case for the…

High Energy Physics - Phenomenology · Physics 2026-05-26 Sebastian Grieninger , Kun Hao , Dmitri E. Kharzeev , Vladimir Korepin

We present a detailed description of the Q^2 and x dependence of the structure functions F2 and FL as extracted from the Deep Inelastic Scattering data at HERA in the small Bjorken x region. Making use of a collinearly-improved BFKL…

High Energy Physics - Phenomenology · Physics 2013-04-10 Martin Hentschinski , Agustin Sabio Vera , Clara Salas

A semiclassical description of structure functions in DIS at small $x$ is presented. It gives an intuitive picture of the transition from the Double Leading Log approximation at large $Q^2$, to the powerlike dependence on $x$ in the BFKL…

High Energy Physics - Phenomenology · Physics 2016-08-16 Gösta Gustafson

We recalculate the gluon Regge trajectory in next-to-leading order to clarify a discrepancy between two results in the literature on the constant part. We confirm the result obtained by Fadin et al.~\cite{FFK}. The effects on the anomalous…

High Energy Physics - Phenomenology · Physics 2009-12-30 J. Blümlein , V. Ravindran , W. L. van Neerven

Starting from the old idea that Fermi statistics for quarks play a fundamental role to explain some features of hadron structure, we study the modification of the scaling behaviour of parton distributions due to quantum statistical effects.…

High Energy Physics - Phenomenology · Physics 2007-05-23 G. Mangano , G. Miele , G. Migliore

We present a global fit to the structure function F_2 measured in lepton-proton experiments at small values of Bjorken-x, x< 0.01, for all experimentally available values of Q^2, 0.045< Q^2 < 800 GeV^2, using the Balitsky -Kovchegov…

High Energy Physics - Phenomenology · Physics 2009-06-16 J. L. Albacete , N. Armesto , J. G. Milhano , C. A. Salgado