Duality between different mechanisms of QCD factorization in γ^*γcollisions

Abstract

We study the phenomenon of duality in hard exclusive reactions to which QCD factorization applies. Considering "two-photon"-like processes in the scalar ${\varphi }_E^3$ model and also hadron-pair production from the collisions of a real (transversely polarized) and a highly virtual, longitudinally polarized, photon in QCD, we identify two regimes of factorization each of them associated with a distinct nonperturbative mechanism. One mechanism involves twist-3 Generalized Distribution Amplitudes, whereas the other one employs leading-twist Transition Distribution Amplitudes. In the case of the scalar ${\varphi }_E^3$ model, we find duality in that kinematical region where the two mechanisms overlap. In the QCD case, the appearance of duality is sensitive to the particular nonperturbative model applied and can, therefore, be used as an additional adjudicator.

14 pages, 8 figures. Substantial changes in the text, 4 figures added, 1 removed; no changes in conclusions

References in corpus (4)

• A Unified Picture for Single Transverse-Spin Asymmetries in Hard Processes
• Moments of pseudoscalar meson distribution amplitudes from the lattice
• Exclusive meson pair production in gamma* gamma scattering at small momentum transfer
• The Pion-Photon Transition Distribution Amplitudes in the Nambu-Jona Lasinio Model

Cited by in corpus (5)

• The Use of Dispersion Relations in Hard Exclusive Processes and the Partonic Interpretation of Deeply Virtual Compton Scattering
• Generalized Parton Distributions of Pions. Spin Structure of Hadrons
• Angular distributions in pion-nucleon Drell-Yan process
• Photon 2009: Summary of Theory Talks
• Duality and Factorization Theorem in QCD