### 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, P_{z} →∞. Since taking such limit is not feasible in lattice simulations, it is essential to provide guidance for what 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 fP_{1}, helicity distribution P_{1}, and transversity distribution hP_{1}). 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 find that the Soffer positivity bound does not hold in general for quasi-PDFs.

Original language | English (US) |
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Article number | 45 |

Journal | Proceedings of Science |

Volume | 26-30-May-2015 |

State | Published - Jan 1 2015 |

Event | 2015 QCD Evolution, QCDEV 2015 - Newport News, United States Duration: May 26 2015 → May 30 2015 |

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### All Science Journal Classification (ASJC) codes

- General

### Cite this

*Proceedings of Science*,

*26-30-May-2015*, [45].