Presented at the 5th Jagiellonian Symposium on Advances in Particle Physics and Medicine, Cracow, Poland, June 29–July 7, 2024

Based on plastic scintillators, Jagiellonian PET (J-PET) is a multi-discipilinary PET scanner having a wide range of applications. With the potential of J-PET to register multiphotons, we aim at exploring the rare and forbidden decay channels of the Positronium triplet state, the ortho-Positronium (o-Ps). The o-Ps decaying into a higher number of photons than the predominant mode (o-Ps 3γ) is six orders of magnitude smaller than expected from the Quantum Electrodynamics (QED) calculations. In this article, we intend to present the status of the preliminary studies of the multi-photon decays of ortho-Positronium. We will explain toy Monte Carlo simulations involving 4- and 5-gamma decays of the o-Ps, together with a preliminary estimation of a J-PET-like detector efficiencies for these channels.