English
Related papers

Related papers: Numerical solution of NLO Q^2 evolution equations …

200 papers

This is the introductory part of my PhD thesis which consists of two parts, the separate introduction and four published articles. The introduction begins by a technically detailed description of the DGLAP evolution and the fast numerical…

High Energy Physics - Phenomenology · Physics 2009-06-16 Hannu Paukkunen

We present an analytical solution for the evolution of parton distributions incorporating mixed-order QCD $\otimes$ QED corrections, addressing both polarized and unpolarized cases. Using the Altarelli-Parisi kernels extended to mixed…

High Energy Physics - Phenomenology · Physics 2026-02-16 Daniel de Florian , Lucas Palma Conte

In this paper, we present {\tt SMKA18} analysis which is a first attempt to extract the set of next-to-next-leading-order (NNLO) spin-dependent parton distribution functions (spin-dependent PDFs) and their uncertainties determined through…

High Energy Physics - Phenomenology · Physics 2018-05-09 Maral Salajegheh , S. Mohammad Moosavi Nejad , Hamzeh Khanpour , S. Atashbar Tehrani

Nuclear parton distributions $f_A(x,Q^2)$ are studied within a framework of the DGLAP evolution. Measurements of $F_2^A/F_2^D$ in deep inelastic $lA$ collisions, and Drell--Yan dilepton cross sections measured in $pA$ collisions are used as…

High Energy Physics - Phenomenology · Physics 2015-06-25 K. J. Eskola , V. J. Kolhinen , P. V. Ruuskanen , C. A. Salgado

We show that to correctly describe the effects of the heavy-quark mass, m_h, in DGLAP evolution, it is necessary to work in the so-called `physical' scheme. In this way, we automatically obtain a smooth transition through the heavy-quark…

High Energy Physics - Phenomenology · Physics 2015-06-16 E. G. de Oliveira , A. D. Martin , M. G. Ryskin , A. G. Shuvaev

We recently derived an explicit expression for the gluon distribution function G(x, Q^2) = xg(x, Q^2) in terms of the proton structure function F_2^{\gamma p} (x, Q^2) in leading-order (LO) QCD by solving the the LO DGLAP equation for the…

High Energy Physics - Phenomenology · Physics 2010-03-25 Martin M. Block , Loyal Durand , Douglas W. McKay

We present a novel semi-analytical method for parton evolution. It is based on constructing a family of analytic functions spanning $x$-space which is closed under the considered evolution equation. Using these functions as a basis, the…

High Energy Physics - Phenomenology · Physics 2025-01-13 Juliane Haug , Oliver Schüle , Fabian Wunder

We present recent progress towards a global determination of parton distribution functions (PDFs) at approximate N$^3$LO (aN$^3$LO) accuracy within the NNPDF framework. We construct a parametrisation of the $\mathcal{O}(\alpha_s^4)$ QCD…

High Energy Physics - Phenomenology · Physics 2023-06-28 Felix Hekhorn , Giacomo Magni

Using Laplace transform techniques, along with newly-developed accurate numerical inverse Laplace transform algorithms, we decouple the solutions for the singlet structure function $F_s(x,Q^2)$ and $G(x,Q^2)$ of the two leading-order…

High Energy Physics - Phenomenology · Physics 2010-04-12 Martin M. Block , Loyal Durand , Phuoc Ha , Douglas W. McKay

We present the next-to-next-to-leading order (NNLO) contributions to the main splitting functions for the evolution of longitudinally polarized parton densities of hadrons in perturbative QCD. The quark-quark and gluon-quark splitting…

High Energy Physics - Phenomenology · Physics 2015-06-22 S. Moch , J. A. M. Vermaseren , A. Vogt

We present an algorithm for massive parton evolution which is based on the differentially accurate simulation of soft-gluon radiation by means of a non-trivial azimuthal angle dependence of the splitting functions. The kinematics mapping is…

High Energy Physics - Phenomenology · Physics 2024-10-04 Benoit Assi , Stefan Höche

An analytical solution of the QCD evolution equations for the singlet and gluon distribution is presented. We decouple DGLAP evolution equations into the initial conditions by using a Laplace transform method at $N^{n}LO$ analysis. The…

High Energy Physics - Phenomenology · Physics 2019-05-13 B. Rezaei , G. R. Boroun

We have computed the complete next-to-next-to-leading order (NNLO) contributions to the splitting functions governing the evolution of unpolarized parton densities in perturbative QCD. Our results agree with all partial results available in…

High Energy Physics - Phenomenology · Physics 2009-11-10 S. Moch , J. A. M. Vermaseren , A. Vogt

The $Q^2$ evolution of polarised parton distributions at small $x$ is studied. Various analytic approximations are critically discussed. We compare the full evolution with that obtained from the leading-pole approximation to the splitting…

High Energy Physics - Phenomenology · Physics 2014-11-17 T. Gehrmann , W. J. Stirling

We present the polarized parton distribution functions from a QCD analysis of the worldwide polarized deep inelastic scattering data, based on the dynamical parton distribution model. All the sea quarks and gluons are dynamically generated…

High Energy Physics - Phenomenology · Physics 2022-11-23 Chengdong Han , Gang Xie , Rong Wang , Xurong Chen

We present a new method to solve in a semianalytical way the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi evolution equations at NLO order in the x-space. The method allows to construct an evolution operator expressed in form of a rapidly…

High Energy Physics - Phenomenology · Physics 2014-11-17 Pietro Santorelli , Egidio Scrimieri

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

The energy dependence for the singlet sector of Parton Distributions Functions (PDFs) is described by an entangled pair of ordinary linear differential equations. Although there are no exact analytic solutions, it is possible to provide…

High Energy Physics - Phenomenology · Physics 2024-02-28 Andrea Simonelli

The parton distributions in the proton are evaluated dynamically using a nonlinear QCD evolution equation - the DGLAP equation with twist-4 (the GLR-MQ-ZSR) corrections - starting from a low scale $\mu^2$, where the nucleon consists of…

High Energy Physics - Phenomenology · Physics 2014-09-11 Xurong Chen , Jianhong Ruan , Rong Wang , Pengming Zhang , Wei Zhu

We extract polarized parton distribution functions (PPDFs), referred to as "KTA17," together with the highly correlated strong coupling $\alpha_s$ from recent and up-to-date $g_1$ and $g_2$ polarized structure functions world data at…

High Energy Physics - Phenomenology · Physics 2017-04-07 Hamzeh Khanpour , Sara Taheri Monfared , S. Atashbar Tehrani