2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/56386Extending previous work on $a_2^{(1)}$, we present a set of reflection matrices, which are explicit solutions to the $a_n^{(1)}$ boundary Yang-Baxter equation. Unlike solutions found previously these are multiplet-changing $K$-matrices, and could therefore be used as soliton reflection matrices for affine Toda field theories on the half-line.6 pagesHigh Energy Physics - Theorytext