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Title: Quasi-parton distribution functions: A study in the diquark spectator model

Abstract

A set of quasi-parton distribution functions (quasi-PDFs) have been recently proposed by Ji. Defined as the matrix elements of equal-time spatial correlations, they can be computed on the lattice and should reduce to the standard PDFs when the proton momentum Pz is very large. Since taking the Pz → ∞ limit is not feasible in lattice simulations, it is essential to provide guidance for what values of Pz the quasi-PDFs are good approximations of standard PDFs. Within the framework of the spectator diquark model, we evaluate both the up and down quarks' quasi-PDFs and standard PDFs for all leading-twist distributions (unpolarized distribution f1, helicity distribution g1, and transversity distribution h1). We find that, for intermediate parton momentum fractions x, quasi-PDFs are good approximations to standard PDFs (within 20–30) when Pz ≳ 1.5–2 GeV. On the other hand, for large x ~ 1 much larger Pz > 4 GeV is necessary to obtain a satisfactory agreement between the two sets. We further test the Soffer positivity bound, and find that it does not hold in general for quasi-PDFs.

Authors:
; ; ;
Publication Date:
Research Org.:
Los Alamos National Laboratory (LANL), Los Alamos, NM (United States); Penn State Berks, Reading, PA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Nuclear Physics (NP); USDOE Laboratory Directed Research and Development (LDRD) Program
OSTI Identifier:
1198586
Alternate Identifier(s):
OSTI ID: 1200902; OSTI ID: 1906136
Grant/Contract Number:  
20130783PRD2; 20130019DR; FG02-07ER41460; AC02-05CH11231
Resource Type:
Published Article
Journal Name:
Physics Letters. B
Additional Journal Information:
Journal Name: Physics Letters. B Journal Volume: 743 Journal Issue: C; Journal ID: ISSN 0370-2693
Publisher:
Elsevier
Country of Publication:
Netherlands
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; 73 NUCLEAR PHYSICS AND RADIATION PHYSICS; Quantum chromodynamics, Parton distributions

Citation Formats

Gamberg, Leonard, Kang, Zhong-Bo, Vitev, Ivan, and Xing, Hongxi. Quasi-parton distribution functions: A study in the diquark spectator model. Netherlands: N. p., 2015. Web. doi:10.1016/j.physletb.2015.02.021.
Gamberg, Leonard, Kang, Zhong-Bo, Vitev, Ivan, & Xing, Hongxi. Quasi-parton distribution functions: A study in the diquark spectator model. Netherlands. https://doi.org/10.1016/j.physletb.2015.02.021
Gamberg, Leonard, Kang, Zhong-Bo, Vitev, Ivan, and Xing, Hongxi. Wed . "Quasi-parton distribution functions: A study in the diquark spectator model". Netherlands. https://doi.org/10.1016/j.physletb.2015.02.021.
@article{osti_1198586,
title = {Quasi-parton distribution functions: A study in the diquark spectator model},
author = {Gamberg, Leonard and Kang, Zhong-Bo and Vitev, Ivan and Xing, Hongxi},
abstractNote = {A set of quasi-parton distribution functions (quasi-PDFs) have been recently proposed by Ji. Defined as the matrix elements of equal-time spatial correlations, they can be computed on the lattice and should reduce to the standard PDFs when the proton momentum Pz is very large. Since taking the Pz → ∞ limit is not feasible in lattice simulations, it is essential to provide guidance for what values of Pz the quasi-PDFs are good approximations of standard PDFs. Within the framework of the spectator diquark model, we evaluate both the up and down quarks' quasi-PDFs and standard PDFs for all leading-twist distributions (unpolarized distribution f1, helicity distribution g1, and transversity distribution h1). We find that, for intermediate parton momentum fractions x, quasi-PDFs are good approximations to standard PDFs (within 20–30) when Pz ≳ 1.5–2 GeV. On the other hand, for large x ~ 1 much larger Pz > 4 GeV is necessary to obtain a satisfactory agreement between the two sets. We further test the Soffer positivity bound, and find that it does not hold in general for quasi-PDFs.},
doi = {10.1016/j.physletb.2015.02.021},
journal = {Physics Letters. B},
number = C,
volume = 743,
place = {Netherlands},
year = {2015},
month = {4}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record
https://doi.org/10.1016/j.physletb.2015.02.021

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Cited by: 38 works
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