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【Abstract】

A 2+1d sheet configuration of the η′ meson bounded by a string (called a pancake or a Hall droplet) is recently proposed to describe the baryons with spin N_c/2. In order to understand its baryon number as well as the flavor quantum number, we argue that the vector mesons (the ρ and ω mesons) should play an essential role for the consistency of the whole picture. We determine the effective theory of large-N_c QCD with N_f massless fermions by taking into account a mixed anomaly involving the theta-periodicity and the global symmetry. The anomaly matching requires the presence of a dynamical domain wall on which a U(N_f)_{−N_c} Chern-Simons theory is supported. We consider the boundary conditions that should be imposed on the edge of the domain wall, and conclude that there should be a boundary term that couples the U(N_f)_{−N_c} gauge field to the vector mesons. We discuss the impact on physics of the chiral phase transition and the relation to the "duality" of QCD. This talk is based on arXiv:2011.14637.