Dynamical explanation of higher-twist cancellations in quark–hadron duality

Determine the dynamical origin of the cancellations among higher-twist contributions that make suitably averaged resonance-region structure functions approximate leading-twist scaling predictions in quark–hadron duality.

Background

The paper describes quark–hadron duality as the empirical observation that averages of resonance-region structure functions closely follow leading-twist scaling curves. Within the operator product expansion, this behavior is associated with small effective higher-twist contributions after averaging, even though individual resonances involve strong nonperturbative effects.

The operator product expansion identifies the suppression of the averaged higher-twist terms but does not explain why the relevant contributions cancel dynamically. The paper identifies the origin of these cancellations as an unresolved topic requiring theoretical investigation using approaches such as lattice QCD, effective field theory, large-N_c methods, and resonance-transition models.