Théorie
Hadronic light-by-light scattering according to holographic QCD
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Europe/Paris
Amphi Besse
Amphi Besse
Description
Conventional hadronic models with a finite number of resonances are incapable of satisfying short-distance constraints on hadronic light-by-light scattering such as the longitudinal Melnikov-Vainshtein (MV) constraint derived from the chiral anomaly and its one-loop exactness. I review how minimal models of holographic QCD naturally solve this problem by their infinite tower of resonances, and to what extent models which include the axial U(1) anomaly lead to a realistic quantitative description. Transverse short-distance constraints that are not fixed by the anomaly are only partially solved and point to the importance of tensor meson contributions.