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.

This is a preprint of an article published in Nature Communications. The final version is available at https://rdcu.be/cCQqq

References in corpus (9)

• Measurement of the fine-structure constant as a test of the Standard Model
• Test of a single module of the J-PET scanner based on plastic scintillators
• J-PET: a new technology for the whole-body PET imaging
• Multichannel FPGA based MVT system for high precision time (20~ps~RMS) and charge measurement
• A feasibility study of ortho-positronium decays measurement with the J-PET scanner based on plastic scintillators
• QED and Fundamental Symmetries in Positronium Decays
• Toward inertial sensing with a monochromatic $2^{3}S$ positronium beam
• Colloquium: Time-reversal violation with quantum-entangled B mesons
• Estimating relationship between the Time Over Threshold and energy loss by photons in plastic scintillators used in the J-PET scanner

Cited by in corpus (19)

• Positronium Physics and Biomedical Applications
• Discrete symmetries tested at 10${}^{-4}$ precision using linear polarization of photons from positronium annihilations
• Multi-photon time-of-flight MLEM application for the positronium imaging in J-PET
• Decoherence puzzle in measurements of photons originating from electron-positron annihilation
• Comparative studies of plastic scintillator strips with high technical attenuation length for the total-body J-PET scanner
• New opportunities for kaonic atoms measurements from CdZnTe detectors
• Measurements of high-n transitions in intermediate mass kaonic atoms by SIDDHARTA-2 at DA$\mathrm{\Phi }$NE
• Pair Production in Circularly Polarized Waves
• J-PET detection modules based on plastic scintillators for performing studies with positron and positronium beams
• TOF MLEM Adaptation for the Total-Body J-PET with a Realistic Analytical System Response Matrix
• Development of the normalization method for the Jagiellonian PET scanner
• First Positronium Lifetime Imaging using ${}^{52}$Mn and ${}^{55}$Co with a plastic-based PET scanner
• Measurement of the ${\text{1}}^{\text{3}}{\text{S}}_{\text{1}}\to {\text{2}}^{\text{3}}{\text{S}}_{\text{1}}$ interval in positronium using field-ionization of Rydberg states
• A reconciliation of the Pryce-Ward and Klein-Nishina statistics for semi-classical simulations of annihilation photons correlations
• First tests of the full SIDDHARTA-2 experimental apparatus with a 4 He gaseous target
• Coupled cluster theory for positron binding in anions and polyatomic molecules
• Many-body theory predictions of positron binding energies in five-membered heterocycles involving N, O, S and NH substituents
• Quantum Entanglement Degree, Mean Positronium Lifetime, and the $3\gamma$/$2\gamma$ Annihilation-Rate Ratio as Novel PET Biomarkers for Hypoxia -- Concept, Challenges, and Predictions
• New constraints on CPT symmetry violation in charm mesons