PERSPECTIVE OF CP VIOLATION SEARCH BY MODULAR J-PET DETECTOR IN THE ORTHO-POSITRONIUM DECAY

The positronium atom, a bound state of electron and positron, is a suitable leptonic test site for Charge-Parity (CP) discrete symmetry research. According to the Standard Model, the photon-photon interaction in the final state due to the vacuum polarization may mimic CP violation of the order of 10(-9), while weak interaction effects lead to a violation of the order of 10(-14). So far, the experimental limits on CP symmetry violation in the decay of o-Ps are set at the level of 10(-3). The J-PET detector can be used to explore discrete symmetries by looking for probable non-zero expectation values of the symmetry-odd operators, constructed from spin of ortho-Positronium (o-Ps) and momentum, and polarization vectors of gamma (gamma) quanta resulting from o-Ps annihilation. The upgraded version of the J-PET detector, with an additional fourth layer of detection modules increases signal acceptance, which allows to triple the efficiency of gamma quanta detection for CP discrete symmetry studies.