Developing Analysis Criteria for Charge-Parity Symmetry Studies Using Photons From Ortho-Positronium Annihilation and Compton Scattering

K.V. Eliyana, b, M. Skurzoka, b, P. Moskala, b on behalf of the J-PET Collaboration) aFaculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, Łojasiewicza 11, 30-348 Kraków, Poland bCenter for Theranostics, Kopernika Street 40, 31-501 Kraków, Poland

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The main aim of this research is to test the charge-parity discrete symmetry in the ortho-positronium (o-Ps) atom decay using the modular Jagiellonian positron emission tomography (J-PET) detector. The J-PET is distinguished by its ability to determine the polarization plane of photons emitted during positronium annihilation. The J-PET detector can investigate discrete symmetry by examining the non-zero expectation values of the symmetry-odd operators constructed from the momentum and direction of polarization plane of gamma (γ) quanta coming from o-Ps annihilation. In positronium decay, the photon-photon interactions in the final state due to vacuum polarization may mimic a charge-parity symmetry violation at the level of 10-9, according to the Standard Model prediction. Currently, with the help of the 192-strip J-PET detector, the experimental limits on charge-parity symmetry violation in o-Ps decay are set at a precision value of 0.0005±0.0007. Using the modular J-PET detector, we aim to improve this value by at least an order of magnitude. This article focuses on developing analysis criteria towards improving the sensitivity level for charge-parity-discrete symmetry studies in o-Ps decay using the modular J-PET detector.

DOI:10.12693/APhysPolA.148.S115 topics: positronium, polarization, charge-parity (CP) symmetry, Jagiellonian positron emission tomography (J-PET)