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Parton distributions and lattice QCD calculations: a community white paper

Authors :
Lin, Huey-Wen
Nocera, Emanuele R.
Olness, Fred
Orginos, Kostas
Rojo, Juan
Accardi, Alberto
Alexandrou, Constantia
Bacchetta, Alessandro
Bozzi, Giuseppe
Chen, Jiunn-Wei
Collins, Sara
Cooper-Sarkar, Amanda
Constantinou, Martha
Del Debbio, Luigi
Engelhardt, Michael
Green, Jeremy
Gupta, Rajan
Harland-Lang, Lucian A.
Ishikawa, Tomomi
Kusina, Aleksander
Liu, Keh-Fei
Liuti, Simonetta
Monahan, Christopher
Nadolsky, Pavel
Qiu, Jian-Wei
Schienbein, Ingo
Schierholz, Gerrit
Thorne, Robert S.
Vogelsang, Werner
Wittig, Hartmut
Yuan, C. -P.
Zanotti, James
Publication Year :
2017

Abstract

In the framework of quantum chromodynamics (QCD), parton distribution functions (PDFs) quantify how the momentum and spin of a hadron are divided among its quark and gluon constituents. Two main approaches exist to determine PDFs. The first approach, based on QCD factorization theorems, realizes a QCD analysis of a suitable set of hard-scattering measurements, often using a variety of hadronic observables. The second approach, based on first-principle operator definitions of PDFs, uses lattice QCD to compute directly some PDF-related quantities, such as their moments. Motivated by recent progress in both approaches, in this document we present an overview of lattice-QCD and global-analysis techniques used to determine unpolarized and polarized proton PDFs and their moments. We provide benchmark numbers to validate present and future lattice-QCD calculations and we illustrate how they could be used to reduce the PDF uncertainties in current unpolarized and polarized global analyses. This document represents a first step towards establishing a common language between the two communities, to foster dialogue and to further improve our knowledge of PDFs.<br />Comment: 80 pages, 15 figures, 28 tables, minor typos corrected, published in Progress in Particle and Nuclear Physics

Details

Database :
arXiv
Publication Type :
Report
Accession number :
edsarx.1711.07916
Document Type :
Working Paper
Full Text :
https://doi.org/10.1016/j.ppnp.2018.01.007