# APEC Seminar (Astronomy - Particle Physics - Experimental Physics - Cosmology)

Speaker: Ryutaro Matsudo (KEK) Vector mesons on the wall Wed, Feb 24, 2021, 13:30 - 14:30 Zoom 2644.pdf We show that the effective theory for pions and $\eta'$ is inconsistent with a mixed anomaly involving the $\theta$-periodicity and the global symmetry unless there is a dynamical domain wall on which a $U(N_f)_{-N_ c}$ Chern-Simons theory is supported. When the domain wall has a boundary, we conclude that there should be a boundary term that couples the $U(N_f)_{-N_c}$ gauge field to the vector mesons. We also confirm that the recent proposal that the domain wall bounded by the string describes the baryon with spin $N_c/2$ by determining the coupling of the background gauge fields to the wall. We discuss the impact on physics of the chiral phase transition and the relation to the duality'' of QCD. This talk is based on the paper arXiv:2011.14637.