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Related papers: Small-x evolution with Q dependence and unitarity

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The proton structure function F2 is studied in the low x regime using BFKL evolution. The next to leading logarithmic (NLL) analysis requires the inclusion of running coupling effects which lead to off-diagonal terms in the evolution…

High Energy Physics - Phenomenology · Physics 2012-06-12 M. Hentschinski , A. Sabio Vera , C. Salas

We present a small x resummation for the GLAP anomalous dimension and its corresponding dual BFKL kernel, which includes all the available perturbative information and nonperturbative constraints. Specifically, it includes all the…

High Energy Physics - Phenomenology · Physics 2010-03-25 Guido Altarelli , Richard D. Ball , Stefano Forte

We investigate the evolution of parton densities at small values of the momentum fraction, x, by including resummed anomalous dimensions in the renormalization group equations. The resummation takes into account the leading-logarithmic…

High Energy Physics - Phenomenology · Physics 2016-09-01 R. K. Ellis , F. Hautmann , B. R. Webber

We derive the evolution equations of parton distribution functions appropriate in different kinematic regions in a unified and simple way using the resummation technique. They include the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi equation…

High Energy Physics - Phenomenology · Physics 2007-05-23 Hsiang-nan Li

We report a semi-analytical approach for the solution of the nonlinear Gribov-Levin-Ryskin-Mueller-Qiu (GLR-MQ) evolution equation for sea quark distribution and investigate the effect of gluon shadowing on the small-x and moderate-Q^2…

High Energy Physics - Phenomenology · Physics 2018-08-09 Mayuri Devee

We discuss several methods of calculating the DIS structure functions F_2(x,Q^2) based on BFKL-type small x resummations. Taking into account new HERA data ranging down to small x and low Q^2, the pure leading order BFKL-based approach is…

High Energy Physics - Phenomenology · Physics 2009-10-30 I. Bojak , M. Ernst

We summarize recent progress in the resummation of perturbative evolution at small x. We show that the problem of incorporating BFKL small x logs in GLAP evolution is now completely solved, and that the main effect of small x resummation is…

High Energy Physics - Phenomenology · Physics 2017-08-23 Stefano Forte , Guido Altarelli , Richard D. Ball

We consider a system of evolution equations for quark and gluon structure functions satisfying the leading-logarithmic behaviour due to both QCD collinear $ \left(LLQ^2 \right) $ and infrared $ (LL1/x) $ singularities. We show that these…

High Energy Physics - Phenomenology · Physics 2008-11-26 R. Peschanski , S. Wallon

We propose a phenomenological study of the Balitsky-Fadin-Kuraev-Lipatov (BFKL) approach applied to the data on the proton structure function $F_2$ measured at HERA in the small-$x_{Bj}$ region ($x_{Bj}<0.01$) and $Q^2$ in the range 5 to…

High Energy Physics - Phenomenology · Physics 2007-05-23 L. Schoeffel

We investigate the energy dependence of the photo-production cross-section of vector mesons $J/\Psi$ and $\Upsilon$, measured by both HERA experiments H1 and ZEUS in electron-proton collisions and by LHC experiments ALICE, CMS and LHCb in…

High Energy Physics - Phenomenology · Physics 2019-08-12 Martin Hentschinski , Krzysztof Kutak

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

We computed the longitudinal proton structure function $F_{L}$, using the nonlinear Dokshitzer-Gribov-Lipatov-Altarelli-parisi (NLDGLAP) evolution equation approach at small $x$. For the gluon distribution, the nonlinear effects are related…

High Energy Physics - Phenomenology · Physics 2014-02-07 G. R. Boroun

The Leding-Logarithmic (LL) gluon Sudakov formfactor is derived from rapidity-ordered BFKL evolution with longitudinal-momentum conservation. This derivation further clarifies the relation between High-Energy and TMD-factorizations and can…

High Energy Physics - Phenomenology · Physics 2021-10-04 Maxim Nefedov

It is well understood that the leading logarithmic approximation for the amplitudes of high energy processes is insufficient and that the next-to-leading logarithmic effects are very large and lead to instability of the solution. The…

High Energy Physics - Phenomenology · Physics 2020-04-22 Michal Deak , Leonid Frankfurt , Mark Strikman , Anna Stasto

It is widely believed that at small x, the BFKL resummed gluon splitting function should grow as a power of 1/x. But in several recent calculations it has been found to decrease for moderately small-x before eventually rising. We show that…

High Energy Physics - Phenomenology · Physics 2014-11-17 Marcello Ciafaloni , Dimitri Colferai , Gavin P. Salam , Anna M. Stasto

Within the framework of the dipole factorisation, we use a recent collinearly-improved version of the Balitsky-Kovchegov equation to fit the HERA data for inclusive deep inelastic scattering at small Bjorken $x$. The equation includes an…

High Energy Physics - Phenomenology · Physics 2020-02-19 B. Ducloué , E. Iancu , G. Soyez , D. N. Triantafyllopoulos

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

This paper presents a solution to the nonlinear small x ``projectile side'' evolution equations as derived by Balitskii in 1996. The solution is based on functional Fokker-Planck methods. The fixed point at small x is explicitly calculated…

High Energy Physics - Phenomenology · Physics 2009-10-31 Heribert Weigert

The evolution of polarized quark distribution functions is taken into account the gluon emission and absorption, quark pair production and annihilation processes and treated by a statistical method which provides quark distribution…

High Energy Physics - Phenomenology · Physics 2016-09-06 Hai Lin

We construct small-x evolution equations which can be used to calculate quark and anti-quark helicity TMDs and PDFs, along with the $g_1$ structure function. These evolution equations resum powers of $\alpha_s \, \ln^2 (1/x)$ in the…

High Energy Physics - Phenomenology · Physics 2016-07-15 Yuri V. Kovchegov , Daniel Pitonyak , Matthew D. Sievert