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Related papers: Large x Resummation in Q^2 Evolution

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DGLAP evolution equations are modified in order to use all the quark families in the full scale range, satisfying kinematical constraints and sumrules, thus having complete continuity for the pdfs and observables. Some consequences of this…

High Energy Physics - Phenomenology · Physics 2011-11-15 C. Pascaud

Linear and non-linear QCD evolutions at high energy suffer from severe issues related to convergence, due to higher order corrections enhanced by large double and single transverse logarithms. We resum double logarithms to all orders by…

High Energy Physics - Phenomenology · Physics 2015-09-29 E. Iancu , J. D. Madrigal , A. H. Mueller , G. Soyez , D. N. Triantafyllopoulos

We investigate effects of threshold resummation of logarithmic corrections $\ln N$ in Mellin space quantitatively. Threshold resummation leads to enhancement of next-to-leading-order QCD predictions for jet production at large jet…

High Energy Physics - Phenomenology · Physics 2015-06-25 Hung-Liang Lai , Hsiang-nan Li

We extend the threshold resummation of the large logarithms $\ln x$ which appear in factorization formulas for exclusive $B$ meson decays, $x$ being a spectator momentum fraction, to the next-to-leading-logarithm (NLL) accuracy. It is shown…

High Energy Physics - Phenomenology · Physics 2021-07-28 Zhi-Qing Zhang , Hsiang-nan Li

The off-diagonal parton-scattering channels $g+\gamma^*$ and $q+\phi^*$ in deep-inelastic scattering are power-suppressed near threshold $x\to 1$. We address the next-to-leading power (NLP) resummation of large double logarithms of $1-x$ to…

High Energy Physics - Phenomenology · Physics 2020-12-02 Martin Beneke , Mathias Garny , Sebastian Jaskiewicz , Robert Szafron , Leonardo Vernazza , Jian Wang

The explicit expressions for the non-singlet DIS structure functions obtained at small x by resumming the most singular logarithmic contributions are discussed and compared in detail with the DGLAP evolution for different values of x and…

High Energy Physics - Phenomenology · Physics 2010-03-25 B. I. Ermolaev , M. Greco , S. I. Troyan

Using the conformal invariance the leading-log evolution of the off-forward structure function is reduced to the forward evolution described by the conventional DGLAP equation. The method relies on the fact that the anomalous dimensions of…

High Energy Physics - Phenomenology · Physics 2014-11-17 A. Shuvaev

Explicit expressions for the non-singlet and singlet structure functions g_1 in the small-x region are obtained. They include the total resummation of the double- and single- logarithms of x and account for the running QCD coupling effects.…

High Energy Physics - Phenomenology · Physics 2016-12-07 B. I. Ermolaev , M. Greco , S. I. Troyan

Recently-developed variational perturbation expansions converge exponentially fast for positive coupling constants. They do not, however, possess the correct left-hand cut in the complex coupling constant plane, implying a wrong large-order…

Quantum Physics · Physics 2009-10-28 H. Kleinert

We show that it is possible to improve the infrared aspects of the standard treatment of the DGLAP evolution theory to take into account a large class of higher order corrections that significantly improve the precision of the theory for…

High Energy Physics - Phenomenology · Physics 2010-03-25 B. F. L. Ward

Resummation techniques are essential for high-precision phenomenology at current and future high-energy collider experiments. Perturbative computations of cross sections often suffer from large logarithmic corrections, which must be…

The resummation of logarithmically-enhanced terms to all perturbative orders is a prerequisite for many studies of QCD final-states. Until now such resummations have always been performed by hand, for a single observable at a time. In this…

High Energy Physics - Phenomenology · Physics 2009-11-10 A. Banfi , G. P. Salam , G. Zanderighi

A matrix-based approach to numerical integration of the DGLAP evolution equations is presented. The method arises naturally on discretisation of the Bjorken x variable, a necessary procedure for numerical integration. Owing to peculiar…

High Energy Physics - Phenomenology · Physics 2014-11-17 Philip G. Ratcliffe

I review recent theoretical progress in the resummation of small x contributions to the evolution of parton distributions, in view of its potential significance for accurate phenomenology at future colliders. I show that a consistent…

High Energy Physics - Phenomenology · Physics 2016-09-06 Stefano Forte

Small-$x$ logarithmic enhancements arising from high-energy gluon emissions affect both the evolution of collinearly-factorized parton densities and partonic coefficient functions. With the higher collider energy reached by the LHC, the…

High Energy Physics - Phenomenology · Physics 2016-11-04 Marco Bonvini , Simone Marzani , Tiziano Peraro

We propose to modify the saturation model of Golec-Biernat and Wusthoff by including DGLAP evolution. We find considerable improvement for the total deep inelastic cross section, in particular in the large Q^2 region. The successful…

High Energy Physics - Phenomenology · Physics 2010-03-25 J. Bartels , K. Golec-Biernat , H. Kowalski

Perturbative corrections beyond leading-log accuracy to BFKL and BK equations, describing the rapidity evolution of QCD scattering amplitudes at high energy, exhibit strong convergence problems due to radiative corrections enhanced by large…

High Energy Physics - Phenomenology · Physics 2015-07-21 E. Iancu , J. D. Madrigal , A. H. Mueller , G. Soyez , D. N. Triantafyllopoulos

The Standard Approach (SA) for description of the structure function g_1 combines the DGLAP evolution equations and Standard Fits for the initial parton densities. The DGLAP equations describe the region of large Q^2 and large x, so there…

High Energy Physics - Phenomenology · Physics 2007-07-13 B. I. Ermolaev , M. Greco , S. I. Troyan

We extend our previous results on small-x resummation in the pure Yang--Mills theory to full QCD with nf quark flavours, with a resummed two-by-two matrix of resummed quark and gluon splitting functions. We also construct the corresponding…

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

We solve the LO DGLAP QCD evolution equation for truncated Mellin moments of the nucleon nonsinglet structure function. The results are compared with those, obtained in the Chebyshev-polynomial approach for $x$-space solutions. Computations…

High Energy Physics - Phenomenology · Physics 2014-11-18 D. Kotlorz , A. Kotlorz