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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 P z is very large. Since taking the P z → ∞ limit is not feasible in lattice simulations, it is essential to provide guidance for which values of P z 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 P z ≳ 1.5–2 GeV. On the other hand, for large x~1 much larger P z > 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:
 [1];  [2];  [2];  [2]
  1. Penn State Berks, Reading, PA (United States)
  2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1198586
Alternate Identifier(s):
OSTI ID: 1200902
Grant/Contract Number:  
FG02-07ER41460; AC02-05CH11231; 20130783PRD2; 20130019DR
Resource Type:
Journal Article: Published Article
Journal Name:
Physics Letters. Section B
Additional Journal Information:
Journal Volume: 743; Journal Issue: C; Journal ID: ISSN 0370-2693
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS

Citation Formats

Gamberg, Leonard, Kang, Zhong -Bo, Vitev, Ivan, and Xing, Hongxi. Quasi-parton distribution functions: A study in the diquark spectator model. United States: 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. United States. doi:10.1016/j.physletb.2015.02.021.
Gamberg, Leonard, Kang, Zhong -Bo, Vitev, Ivan, and Xing, Hongxi. Thu . "Quasi-parton distribution functions: A study in the diquark spectator model". United States. doi: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 which 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. Section B},
number = C,
volume = 743,
place = {United States},
year = {Thu Feb 12 00:00:00 EST 2015},
month = {Thu Feb 12 00:00:00 EST 2015}
}

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

Citation Metrics:
Cited by: 12 works
Citation information provided by
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