On convergence properties of GPD expansion through Mellin/conformal moments and orthogonal polynomials

Autor: Hao-Cheng Zhang, Xiangdong Ji
Jazyk: angličtina
Rok vydání: 2025
Předmět:
Zdroj: Nuclear Physics B, Vol 1010, Iss , Pp 116762- (2025)
Druh dokumentu: article
ISSN: 0550-3213
DOI: 10.1016/j.nuclphysb.2024.116762
Popis: We examine convergence properties of reconstructing the generalized parton distributions (GPDs) through the universal moment parameterization (GUMP). We provide a heuristic explanation for the connection between the formal summation/expansion and the Mellin-Barnes integral in the literature, and specify the exact convergence condition. We derive an asymptotic condition on the conformal moments of GPDs to satisfy the boundary condition at x=1 and subsequently develop an approximate formula for GPDs when x>ξ. Since experimental observables constraining GPDs can be expressed in terms of double or even triple summations involving their moments, scale evolution factors, and Wilson coefficients, etc., we propose a method to handle the ordering of the multiple summations and convert them into multiple Mellin-Barnes integrals via analytical continuations of integer summation indices.
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