2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/45729Here we discuss three separate topics in charmonium physics. (1) The Omicron \OMC as $1^{--}$ trigluonia, and the charmonium puzzle; the $η_c' (3600)$ search. (2) The decay $ψ(^1P_1) \to π^o + J/ψ$ and isospin violating charmonium decays. (3) How to search for $χ_c' = χ_c(2P)$ charmonium states.7 pages, LATEX formatHigh Energy Physics - Phenomenologytext