2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/46411This thesis examines three problems of the quark model, split between two general areas. The general areas are: 1) models of meson decay ($^3P_0$ and flux-tube breaking), 2) final state interactions (FSI's). The three specific problems are: 1) identification of the $f_4(2220)$ state, 2) determination of the mixing angle between the $K_1(1270)$ and $K_1(1400)$ mesons, 3) examination of FSI's in the reaction $γγ\rightarrow ππ$ near threshold. A more complete abstract is included in the thesis.Ph.D. thesis, 137 pages, latexHigh Energy Physics - PhenomenologyNuclear Theorytext