Testing momentum dependence of the nonperturbative hadron structure in a global QCD analysis
Abstract
We discuss strategies for comparisons of nonperturbative QCD predictions for parton distribution functions (PDFs) with high-energy experiments in the region of large partonic momentum fractions x . Analytic functional forms for PDFs cannot be uniquely determined solely based on discrete experimental measurements because of a mathematical property of mimicry of PDF parametrizations that we prove using a representation based on Bézier curves. Predictions of nonperturbative QCD approaches for the x dependence of PDFs instead should be cast in a form that enables decisive comparisons against experimental measurements. Predictions for effective power laws of (1 -x ) dependence of PDFs may play this role. Expectations for PDFs in a proton based on quark counting rules are compared against the effective power laws of (1 -x ) dependence satisfied by CT18 next-to-next-to-leading-order parton distributions. We comment on implications for studies of PDFs in a pion, in particular on the comparison of nonperturbative approaches with phenomenological PDFs.
- Publication:
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Physical Review D
- Pub Date:
- March 2021
- DOI:
- 10.1103/PhysRevD.103.054029
- arXiv:
- arXiv:2011.10078
- Bibcode:
- 2021PhRvD.103e4029C
- Keywords:
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- High Energy Physics - Phenomenology
- E-Print:
- 23 pages, 8 figures