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New Perspectives for QCD: The Novel Effects of Final-State Interactions and Near-Conformal Effective Couplings

S. J. Brodsky
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Abstract

The effective QCD charge extracted from $τ$ decay is remarkably constant at small momenta, implying the near-conformal behavior of hadronic interactions at small momentum transfer. The correspondence of large-$N_C$ supergravity theory in higher-dimensional anti-de Sitter spaces with gauge theory in physical space-time also has interesting implications for hadron phenomenology in the conformal limit, such as constituent counting rules for hard exclusive processes. The utility of light-front quantization and light-front Fock wavefunctions for analyzing such phenomena and representing the dynamics of QCD bound states is reviewed. I also discuss the novel effects of initial- and final-state interactions in hard QCD inclusive processes, including Bjorken scaling single-spin asymmetries and the leading-twist diffractive and shadowing contributions to deep inelastic lepton-proton scattering.

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S. J. Brodsky. 2003-10-25. New Perspectives for QCD: The Novel Effects of Final-State Interactions and Near-Conformal Effective Couplings. https://arxiv.org/abs/hep-ph/0310289

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