Recent results on the positronium decay studies with the J-PET detector

Abstract

Positronium, as a bound state of electron and positron and the lightest matter-antimatter system and at the same time an eigenstate of the C and P operators is a unique probe to search for possible violation of combined charge, parity, and time-reversal symmetries (CPT). The test is performed by a measurement of angular correlations in the annihilations of the lightest leptonic bound system. The J-PET detector is the only device which enables the determination of the polarization of photons from positronium annihilation together with the positronium spin axis on an event-by-event basis. This allows to explore a new class of discrete symmetry odd operators that were not investigated before. The first test of CPT symmetry at J-PET is presented together with preliminary results of CP, P and T symmetry test.