2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/177776We analyze the role of final state interactions in decay of the lighest exotic meson, $pi_1$ with $J^{PC}=1^{-+}. We use the relativistic Lippmann-Schwinger equation for two coupled $πb_{1}$ and $πρ$ channels. The first one is the predicted dominant decay mode of the $π_{1}$, whereas in the other a narrow $π_1(1600)$ exotic signal has been reported by the E852 collaboration. The FSI potential is constructed, based on the $ω$ meson exchange between the two channels. We find that this process introduces corrections to the $π_{1}$ widths of the order of only a few MeV. Therefore, we conclude that a substantial $πρ$ mode cannot be generated through level mixing.7 pages, 11 figuresHigh Energy Physics - Phenomenologytext