2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/196088We calculate the two-loop QCD corrections to paracharmonium decays $eta_{c} rightarrow gamma gamma$ and $eta_{c} rightarrow g g$ involving light-by-light scattering diagrams with light quark loops. Artificial large mass expansion and convergence improvement techniques are used to evaluate these corrections. The obtained corrections to the decays $eta_{c} rightarrow gamma gamma$ and $eta_{c} rightarrow g g$ account for $-1.25 %$ and $ -0.73 %$ of the leading order contribution, respectively.24 pages, 10 figures; REVTeX version; Version to appear in Phys. Rev. D, 9 pages, 4 figuresHigh Energy Physics - Phenomenologytext