Constraints of ξ-moments computed using QCD sum rules on piondistribution amplitude models*

Abstract

Abstract To date, the behavior of the pionic leading-twist distribution amplitude (DA) which is a universal physical quantity and is introduced into high-energy processes involving pions based on the factorization theorem is not completely consistent. The form of is usually described by phenomenological models and constrained by the experimental data on exclusive processes containing pions or the moments computed using QCD sum rules and the lattice QCD theory. Evidently, an appropriate model is extremely important to determine the exact behavior of . In this paper, by adopting the least squares method to fit the ξ-moments calculated using QCD sum rules based on the background field theory, we perform an analysis on several commonly used models of the pionic leading-twist DA in the literature; these include the truncation form of the Gegenbauer polynomial series, the light-cone harmonic oscillator model, the form extracted from the Dyson-Schwinger equations, the model from the light-front holographic AdS/QCD, and a simple power-law parametrization form.