We study the worldsheet theory of a single infinitely long confining string; it defines relativistic 1+1 dimensional theory whose low energy excitation are Goldstone bosons of the spontaneously broken spacetime symmetry. It has been observed in lattice simulations that the worldsheet theory also contains a massive pseudo-scalar excitation - "worldsheet axion". The space of effective theory of a long string for the first two non-universal, irrelevant coefficients is bounded by numerical S-matrix bootstrap. The theories that live on the boundary of this space also contains a pseudo-scalar particle. We construct theories that live on the boundary of this space in a scaling limit. Our construction sheds light on properties of the worldsheet axion and also predicts behavior of the higher irrelevant coupling in our scaling asymptotic limit.
Zoom link: https://icts-res-in.zoom.us/j/88092766911?pwd=R3ZrVk9yeW96ZmQ4ZG9KRzVhenRKZz09
Meeting ID: 880 9276 6911