Parton distributions and lattice-QCD calculations: Toward 3D structure

Journal Article · 25 August 2021 · Prog.Part.Nucl.Phys.

DOI:https://doi.org/10.1016/j.ppnp.2021.103908· OSTI ID:1843473

Constantinou, Martha ^[1]; Courtoy, Aurore ^[2]; Ebert, Markus A. ^[3]; Engelhardt, Michael ^[4]; Giani, Tommaso ^[5]; Hobbs, Tim ^[6]; Hou, Tie-Jiun ^[7]; Kusina, Aleksander ^[8]; Kutak, Krzysztof ^[8]; Liang, Jian ^[9]; Lin, Huey-Wen ^[10]; Liu, Keh-Fei ^[9]; Liuti, Simonetta ^[11]; Mezrag, Cédric ^[12]; Nadolsky, Pavel ^[13]; Nocera, Emanuele R. ^[14]; Olness, Fred ^[13]; Qiu, Jian-Wei ^[15]; Radici, Marco ^[16]; Radyushkin, Anatoly ^[17] ; Rajan, Abha ^[18]; Rogers, Ted ^[17]; Rojo, Juan ^[19]; Schierholz, Gerrit ^[20]; Yuan, C.-P. ^[10]; Zhang, Jian-Hui ^[21]; Zhang, Rui ^[10]

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1. Temple U.
2. Mexico U.
3. MIT, Cambridge, CTP
4. New Mexico State U.
5. U. Edinburgh, Higgs Ctr. Theor. Phys.
6. Southern Methodist U.; Jefferson Lab; Fermilab; IIT, Chicago
7. Shenyang, Northeast U. Tech.
8. Cracow, INP
9. U. Kentucky, Lexington
10. Michigan State U.
11. Virginia U.
12. IRFU, Saclay
13. Southern Methodist U.
14. NIKHEF, Amsterdam
15. Jefferson Lab
16. INFN, Pavia; Pavia U.
17. Jefferson Lab; Old Dominion U.
18. Brookhaven
19. NIKHEF, Amsterdam; Vrije U., Amsterdam
20. DESY
21. Beijing Normal U.

The strong force which binds hadrons is described by the theory of quantum chromodynamics (QCD). Determining the character and manifestations of QCD is one of the most important and challenging outstanding issues necessary for a comprehensive understanding of the structure of hadrons. Within the context of the QCD parton picture, the parton distribution functions (PDFs) have been remarkably successful in describing a wide variety of processes. However, these PDFs have generally been confined to the description of collinear partons within the hadron. New experiments and facilities provide the opportunity to additionally explore the transverse structure of hadrons which is described by generalized parton distributions (GPDs) and transverse-momentum-dependent parton distribution functions (TMD PDFs). In our previous report Lin et al. (2018), we compared and contrasted the two main approaches used to determine the collinear PDFs: the first based on perturbative QCD factorization theorems, and the second based on lattice-QCD calculations. In the present report, we provide an update of recent progress on the collinear PDFs, and also expand the scope to encompass the generalized PDFs (GPDs and TMD PDFs). We review the current state of the various calculations, and consider what new data might be available in the near future. We also examine how a shared effort can foster dialog between the PDF and lattice-QCD communities, and yield improvements for these generalized PDFs.

• Research Organization: Beijing Normal U.; DESY; Vrije U., Amsterdam; Shenyang, Northeast U. Tech.; U. Kentucky, Lexington; NIKHEF, Amsterdam; New Mexico State U.; Virginia U.; Cracow, INP; Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States); MIT, Cambridge, CTP; Michigan State U.; INFN, Pavia; U. Edinburgh, Higgs Ctr. Theor. Phys.; IRFU, Saclay; Old Dominion U.; Temple U.; Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Brookhaven National Laboratory (BNL), Upton, NY (United States); IIT, Chicago; Mexico U.; Southern Methodist U.; Pavia U.
• Sponsoring Organization: US Department of Energy
• DOE Contract Number: AC02-07CH11359
• OSTI ID: 1843473
• Report Number(s): Nikhef 2020-018; MIT-CTP/5213; MSUHEP-20-012; IFJPAN-IV-2020-3; SMU-HEP-20-03; DESY-20-109; FERMILAB-PUB-20-787-SCD; oai:inspirehep.net:1801417; arXiv:2006.08636
• Journal Information: Prog.Part.Nucl.Phys., Journal Name: Prog.Part.Nucl.Phys. Vol. 121
• Country of Publication: United States
• Language: English

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