Speaker
Description
One of the enduring challenges in fundamental physics is rigorously quantifying deviations from, or upholding the exactness of, discrete symmetries observed in nature. Measurements of angular correlations in the decays of polarized positronium (Ps) provide a sensitive probe for testing CPT symmetry in the electroweak interactions [1]. Due to its unique nature as the lightest bound state of an electron and its antiparticle, Ps plays a critical role in searches for CPT violation. The Jagiellonian Positron Emission Tomograph (J-PET) detector, employing plastic scintillators, facilitates high-precision measurements of these angular correlations in Ps decays [2]. J-PET has demonstrably achieved a sensitivity level of 10$^{−4}$ in its initial CPT symmetry test [3], which involved searching for non-vanishing CPT-violating correlations between the spin of polarized $^{3}$S$_{1}$ positronium and the momenta of its annihilation photons. Notably, J-PET has also established stringent limits on the CP symmetry test using the polarization of photons [4]. This work explores avenues for further enhancing the sensitivity of the CPT symmetry test by increasing the ortho-positronium (o-Ps) detection efficiency with a new detector prototype.
References
[1] W. Bernreuther, U. Low, J.P. Ma, O. Nachtmann, Z. Phys. C 41 (1988) 143
[2] P. Moskal et al., Acta Phys. Polon. B 47 (2016) 509
[3] P. Moskal et al., Nat. Commun. 12 (2021) 5658
[4] P. Moskal et al., Nat. Commun. 15 (2024) 78
