A study of quasi-parton distribution functions in the diquark spectator model

Leonard Gamberg, Zhong Bo Kang, Ivan Vitev, Hongxi Xing

Research output: Contribution to journalConference article

2 Citations (Scopus)

Abstract

To facilitate lattice QCD calculations of nucleon structute, a set of quasi-parton distributions were recently introduced. These quasi-PDFs were shown to reduce to standard PDFs when the nucleon is boosted to high energies, Pz →∞. Since taking such 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 fP1, helicity distribution P1, and transversity distribution hP1). 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 find that the Soffer positivity bound does not hold in general for quasi-PDFs.

Original languageEnglish (US)
Article number45
JournalProceedings of Science
Volume26-30-May-2015
StatePublished - Jan 1 2015
Event2015 QCD Evolution, QCDEV 2015 - Newport News, United States
Duration: May 26 2015May 30 2015

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partons
distribution functions
approximation
quantum chromodynamics
quarks
momentum
simulation
energy

All Science Journal Classification (ASJC) codes

  • General

Cite this

Gamberg, Leonard ; Kang, Zhong Bo ; Vitev, Ivan ; Xing, Hongxi. / A study of quasi-parton distribution functions in the diquark spectator model. In: Proceedings of Science. 2015 ; Vol. 26-30-May-2015.
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A study of quasi-parton distribution functions in the diquark spectator model. / Gamberg, Leonard; Kang, Zhong Bo; Vitev, Ivan; Xing, Hongxi.

In: Proceedings of Science, Vol. 26-30-May-2015, 45, 01.01.2015.

Research output: Contribution to journalConference article

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AU - Kang, Zhong Bo

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N2 - To facilitate lattice QCD calculations of nucleon structute, a set of quasi-parton distributions were recently introduced. These quasi-PDFs were shown to reduce to standard PDFs when the nucleon is boosted to high energies, Pz →∞. Since taking such 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 fP1, helicity distribution P1, and transversity distribution hP1). 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 find that the Soffer positivity bound does not hold in general for quasi-PDFs.

AB - To facilitate lattice QCD calculations of nucleon structute, a set of quasi-parton distributions were recently introduced. These quasi-PDFs were shown to reduce to standard PDFs when the nucleon is boosted to high energies, Pz →∞. Since taking such 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 fP1, helicity distribution P1, and transversity distribution hP1). 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 find that the Soffer positivity bound does not hold in general for quasi-PDFs.

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