2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/45129The experimental information on the search for non $q \bar q$ mesons as glueballs, hybrids and multiquark states is reviewed. Candidate states which are particularly amenable to detailed study by accumulating large samples of $J/ψ$, $η_c$, $χ$ decays at a $τ$-charm factory are discussed.25 pages, LaTex, 22 Figures (available from the authors on request), BARI-TH/94-172High Energy Physics - Phenomenologytext