PositroniumPs is a system consisting of an electron and a positron bound together into an “hydrogenoid atom”. Ground statePs is formed for 75% as ortho-Ps (spin 1) and for 25% as para-Ps (spin 0). Para-Ps annihilates in two gamma rays with 511 keV each and ortho-Ps in vacuum is required to annihilate into three gamma rays at least, with a maximum … Leggi tutto Positronium