Quasi Parton Distribution Functions in Covariant Quark Models
Abstract
Quasi parton distribution functions (QPDFs) are defined in terms of QCD fields at spacelike separations evaluated in matrix elements of hadrons moving with velocity v. These objects can be studied in lattice QCD. In the limit when v approaches the speed of light, QPDFs converge to PDFs. It is insightful to study QPDFs and their convergence in models. In this work, we first study the QPDFs in a broad class of quark models characterized by one common feature, namely the absence of gauge degrees of freedom. We provide general proofs for the convergence and sum rules of the unpolarized quark and antiquark QPDFs for both choices γ0 and γ3. We choose the Covariant Parton Model (CPM) as an illustration. We derive analytical results for the small-xv behavior of QPDFs and the energy-momentum tensor form factor c̅q(t) at zero momentum transfer. These results are of interest as they correspond to a Wandzura-Wilczek-type approximation.
Versions
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BibTeX
@misc{aslan2026quasi,
title = {{Quasi Parton Distribution Functions in Covariant Quark Models}},
author = {Fatma Aslan and Asli Tandogan and Peter Schweitzer},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2605.12373},
eprint = {2605.12373},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2605.12373},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Quasi Parton Distribution Functions in Covariant Quark Models
AU - Fatma Aslan
AU - Asli Tandogan
AU - Peter Schweitzer
PY - 2026
DA - 2026/10/30
PB - arXiv
DO - 10.48550/arxiv.2605.12373
UR - https://arxiv.org/abs/2605.12373
AB - Quasi parton distribution functions (QPDFs) are defined in terms of QCD fields at spacelike separations evaluated in matrix elements of hadrons moving with velocity v. These objects can be studied in lattice QCD. In the limit when v approaches the speed of light, QPDFs converge to PDFs. It is insightful to study QPDFs and their convergence in models. In this work, we first study the QPDFs in a broad class of quark models characterized by one common feature, namely the absence of gauge degrees of freedom. We provide general proofs for the convergence and sum rules of the unpolarized quark and antiquark QPDFs for both choices γ^0 and γ^3. We choose the Covariant Parton Model (CPM) as an illustration. We derive analytical results for the small-x_v behavior of QPDFs and the energy-momentum tensor form factor c̅^q(t) at zero momentum transfer. These results are of interest as they correspond to a Wandzura-Wilczek-type approximation.
ER -