Baryon Junction and String Interactions: Part II

We study junctions between confining strings. These junctions arise in Yang-Mills theories, and we focus on their universal low-energy dynamics. Using open-closed duality, we map junctions with nonlinear corrections to the $s$-wave scattering amplitudes between confining string loops. In $(3+1)$ dimensions, we uncover an accidental $\mathbb{Z}_2$ symmetry. This symmetry implies novel selection rules for loop scattering amplitudes and is broken by the junction mass at subleading order. We determine the total mass of baryons up to order $(\text{baryon size})^{-3}$, providing new, testable predictions for lattice simulations.