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Related papers: The HOPPET NNLO parton evolution package

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We present a new regression model for the determination of parton distribution functions (PDF) using techniques inspired from deep learning projects. In the context of the NNPDF methodology, we implement a new efficient computing framework…

High Energy Physics - Phenomenology · Physics 2019-09-04 Stefano Carrazza , Juan Cruz-Martinez

In this proceedings we describe the computational challenges associated to the determination of parton distribution functions (PDFs). We compare the performance of the convolution of the parton distributions with matrix elements using…

High Energy Physics - Phenomenology · Physics 2019-09-25 Stefano Carrazza , Juan Cruz-Martinez , Jesús Urtasun-Elizari , Emilio Villa

The interest into parton distribution functions (PDFs) and fragmentation functions (FFs) in current high energy physics research is twofold. On the one hand, they are fundamental objects to conduct precision phenomenology studies, e.g. at…

High Energy Physics - Phenomenology · Physics 2025-09-22 Tanishq Sharma

We present a new QCD evolution library for unpolarized parton distribution functions: EKO. The program solves DGLAP equations up to next-to-next-to-leading order. The unique feature of EKO is the computation of solution operators, which are…

High Energy Physics - Phenomenology · Physics 2022-11-15 Alessandro Candido , Felix Hekhorn , Giacomo Magni

In this talk, we present the results from our recent global reanalysis of nuclear parton distribution functions (nPDFs), where the DGLAP-evolving nPDFs are constrained by nuclear hard process data from deep inelastic $l+A$ scattering (DIS)…

High Energy Physics - Phenomenology · Physics 2008-11-26 K. J. Eskola , V. J. Kolhinen , H. Paukkunen , C. A. Salgado

We review the current status of the global DGLAP analysis of nuclear parton distribution functions, nPDFs, focusing on the recent EPS09 analysis, whose output, EPS09NLO, is the best-constrained NLO nPDF set on the market. Collinear…

High Energy Physics - Phenomenology · Physics 2015-05-20 K. J. Eskola , H. Paukkunen , C. A. Salgado

In this talk, we present our recent next-to-leading order (NLO) nuclear parton distribution functions (nPDFs), which we call EPS09. As an extension to earlier NLO analyses, we supplement the deep inelastic scattering and Drell-Yan dilepton…

High Energy Physics - Phenomenology · Physics 2009-11-18 Kari J. Eskola , Hannu Paukkunen , Carlos A. Salgado

In this paper, we discuss the algorithms used in the LO evolution program for nondiagonal parton distributions in the DGLAP region and discuss the stability of the code. Furthermore, we demonstrate that we can reproduce the case of the LO…

High Energy Physics - Phenomenology · Physics 2007-05-23 Andreas Freund , Vadim Guzey

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

In this talk, we present our recent work on next-to-leading order (NLO) nuclear parton distribution functions (nPDFs), which we call EPS09. As an extension to earlier NLO analyses, we complement the deep inelastic scattering and Drell-Yan…

High Energy Physics - Phenomenology · Physics 2009-06-17 Kari J. Eskola , Hannu Paukkunen , Carlos A. Salgado

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

Numerical solution of DGLAP $Q^2$ evolution equations is studied for polarized parton distributions by using a ``brute-force" method. NLO contributions to splitting functions are recently calculated,and they are included in our analysis.…

High Energy Physics - Phenomenology · Physics 2007-05-23 M. Hirai , S. Kumano , M. Miyama

We formulate the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) evolution of the Deep Inelastic Scattering (DIS) structure functions $F_2$ and $F_{\rm L}$ at next to leading order in $\alpha_s$ (NLO) directly in terms of the structure…

High Energy Physics - Phenomenology · Physics 2024-07-17 Tuomas Lappi , Heikki Mäntysaari , Hannu Paukkunen , Mirja Tevio

Parton Distribution Functions (PDFs) model the parton content of the proton. Among the many collaborations which focus on PDF determination, NNPDF pioneered the use of Neural Networks to model the probability of finding partons (quarks and…

Computational Physics · Physics 2020-07-21 Juan M Cruz-Martinez , Stefano Carrazza , Roy Stegeman

We present a parton shower which implements the DGLAP evolution of parton densities and fragmentation functions at next-to-leading order precision up to effects stemming from local four-momentum conservation. The Monte-Carlo simulation is…

High Energy Physics - Phenomenology · Physics 2017-11-01 Stefan Höche , Frank Krauss , Stefan Prestel

This paper describes the design and work of a set of computer routines capable for numerical computation of generalized parton distributions (GPDs) evolution at the leading order. The main intention of this work is to present a fast-working…

High Energy Physics - Phenomenology · Physics 2007-05-23 A. V. Vinnikov

We formulate and numerically solve the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi~(DGLAP) evolution equations at next-to-leading order in perturbation theory directly for a basis of 6 physical, observable structure functions in deeply…

High Energy Physics - Phenomenology · Physics 2025-09-03 Tuomas Lappi , Heikki Mäntysaari , Hannu Paukkunen , Mirja Tevio

We investigate numerical solution of the Dokshitzer-Gribov-Lipatov-Altarelli- Parisi (DGLAP) Q^2 evolution equation for the transversity distribution Delta_T q or the structure function h_1. The leading-order (LO) and next-to- leading-order…

High Energy Physics - Phenomenology · Physics 2014-11-17 M. Hirai , S. Kumano , M. Miyama

We present a determination of the parton distributions of the nucleon from a global set of hard scattering data using the NNPDF methodology: NNPDF2.0. Experimental data include deep-inelastic scattering with the combined HERA-I dataset,…

High Energy Physics - Phenomenology · Physics 2014-11-20 Richard D. Ball , Luigi Del Debbio , Stefano Forte , Alberto Guffanti , Jose I. Latorre , Juan Rojo , Maria Ubiali

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