Conveners
Positronium in fundamental investigations: Invited talks
- Kenji SHIMAZOE (The University of Tokyo)
Positronium in fundamental investigations: Contributed talks
- Zdenka Kuncic (University of Sydney, Australia)
Positronium in fundamental investigations: Future prospects
- Mihael Makek (Faculty of Science, University of Zagreb)
Recently, theoretical and experimental papers have been published that put forward different interpretations about the physics of the photons produced in positronium decay. Most of the publications claim that their data prove quantum entanglement. This talk will give an overview of the underlying assumptions and the prospects of the upcoming experiments.
The Jagiellonian Positron Emission Tomograph (J-PET) is the first PET scanner based on plastic scintillators.
It is designed to measure momentum vectors and the polarization of photons originating from the decays of positronium.
In combination with the newly invented positronium imaging method, J-PET enables the study of discrete symmetries in positronium without the use of magnetic fields....
We will present an overview of the activities undertaken with the experimental system based on single layer gamma-ray polarimeter. This modular system consist of 16 position sensitive scintillator matrices read out by silicon photomultipliers. We have shown that these simple detectors can successfully measure the polarization of gamma rays via internal Compton scattering. Owing to its...
We give an overview of basic concepts and formulas used in simulating the Compton scattering. Special emphasis is given to a Klein-Nishina expression for a differential scattering cross section for a single photon. In a context of entangled annihilation photons, a scattering of single (uncorrelated) photons is a reference point for gauging the quantum effects due to the entanglement itself. As...
Recently, different groups have performed measurement of polarization correlations of annihilation quanta after inducing decoherence of one of the gammas by Compton scattering yielding somewhat contradictory results. Watts et al. [Nat. Commun., 12, 2646, (2021)] reported the result hinting at loss of correlation, while Abdurashitov et. al. [Jour. Inst. 17, P03010, (2022)] reported strong...
An overview of the previous measurements of the polarization of photons in positronium annihilations, with special emphasis on ortho-positronium annihilations, will be given. Possibilities for the measurements of the polarization of all three photons in ortho-positronium annihilations with single-layer Compton scattering detector systems developed at the Department of Physics in Zagreb as well...
One of three Sahkarov conditions needed to explain the matter-antimatter asymmetry problem is the existence of CP symmetry breaking. This was indeed observed in the quark sector but with the magnitude which is not large enough to solve the matter-antimatter asymmetry problem. Since the CP violation is allowed by some leptogenesis models, the search for additional CP symmetry breaking was...
I shall discuss opportunities to do underground experiments by presenting our investigations of possible departures from the standard quantum mechanics’ predictions at the Gran Sasso underground laboratory in Italy.
In particular, with refined radiation detectors we are searching signals predicted by the dynamical collapse models (spontaneous emission of radiation) which were proposed to...
