Testing CPT symmetry in ortho-positronium decays with positronium annihilation tomography
Abstract
Charged lepton system symmetry under combined charge, parity, and time-reversal transformation (CPT) remains scarcely tested. Despite stringent quantum-electrodynamic limits, discrepancies in predictions for the electron-positron bound state (positronium atom) motivate further investigation, including fundamental symmetry tests. While CPT noninvariance effects could be manifested in non-vanishing angular correlations between final-state photons and spin of annihilating positronium, measurements were previously limited by knowledge of the latter. Here, we demonstrate tomographic reconstruction techniques applied to three-photon annihilations of ortho-positronium atoms to estimate their spin polarisation without magnetic field or polarised positronium source. We use a plastic-scintillator-based positron-emission-tomography scanner to record ortho-positronium (o-Ps) annihilations with single-event estimation of o-Ps spin and determine the complete spectrum of an angular correlation operator sensitive to CPT-violating effects. We find no violation at the precision level of 10^{-4}, with an over threefold improvement on the previous measurement.
Keywords
Cite
@article{arxiv.2112.04235,
title = {Testing CPT symmetry in ortho-positronium decays with positronium annihilation tomography},
author = {Paweł Moskal and Aleksander Gajos and Muhsin Mohammed and Jyoti Chhokar and Neha Chug and Catalina Curceanu and Eryk Czerwiński and Meysam Dadgar and Kamil Dulski and Marek Gorgol and Jacek Goworek and Beatrix Hiesmayr and Bożena Jasińska and Krzysztof Kacprzak and Łukasz Kapłon and Hanieh Karimi and Daria Kisielewska and Konrad Klimaszewski and Grzegorz Korcyl and Paweł Kowalski and Nikodem Krawczyk and Wojciech Krzemień and Tomasz Kozik and Ewelina Kubicz and Szymon Niedźwiecki and Szymon Parzych and Monika Pawlik-Niedźwiecka and Lech Raczyński and Juhi Raj and Sushil Sharma and Shivani Choudhary and Roman Shopa and Andrzej Sienkiewicz and Michał Silarski and Magdalena Skurzok and Ewa Stępień and Faranak Tayefi and Wojciech Wiślicki},
journal= {arXiv preprint arXiv:2112.04235},
year = {2021}
}
Comments
This is a preprint of an article published in Nature Communications. The final version is available at https://rdcu.be/cCQqq