Related papers: QED and Fundamental Symmetries in Positronium Deca…
Despite its very short lifetime positronium provides us with a number of accurate tests of the bound state QED. In this note a brief overview of QED theory and precision experiments on the spectrum and annihilation decay of the positronium…
Discrete symmetries play an important role in particle physics with violation of CP connected to the matter-antimatter imbalance in the Universe. We report the most precise test of P, T and CP invariance in decays of ortho-positronium,…
Positronium is a unique laboratory to study fundamental symmetries in the Standard Model, reflection in space ($\mathcal{P}$), reversal in time ($\mathcal{T}$), charge conjugation ($\mathcal{C}$) and their combinations. The experimental…
High-order perturbative corrections to positronium decays and hyperfine splitting are briefly reviewed. Theoretical predictions are compared to the most recent experimental data. Perspectives of future calculations are discussed.
The construction of positronium decay amplitudes is handled through the use of dispersion relations. In this way, emphasis is put on basic QED principles: gauge invariance and soft-photon limits (analyticity). A firm grounding is given to…
Positronium, the electron-positron bound state, is described to a good approximation by pure QED. The states of positronium have definite values of C and P. Consequently, positronium is an attractive system for the investigation of possible…
The Positronium (Ps) system, a bound state of an electron and a positron, is suitable for testing the predictions of quantum electrodynamics (QED), since its properties can be perturbatively calculated to high accuracy and, unlike the…
As an unstable light pure leptonic system, positronium is a very specific probe atom to test bound state QED. In contrast to ordinary QED for free leptons, the bound state QED theory is not so well understood and bound state approaches…
Fundamental symmetry tests with neutrons can provide unique information about whatever will be the new Standard Model of fundamental interactions. I review two aspects of this possibility: searches for the permanent electric dipole moment…
We briefly review the theoretical and experimental results concerning decays of positronium. Possible solutions of the "orthopositronium lifetime puzzle" are discussed. Positronium annihilation into neutrinos is examined and disagreement is…
Theory results on precision measurements in electron-positron annihilation at low and high energies are collected. These cover pure QCD calculations as well as mixed electroweak and QCD results, involving light and heavy quarks. The impact…
In this paper we present prospects for using the J-PET detector to search for discrete symmetries violations in a purely leptonic system of the positronium atom. We discuss tests of CP and CPT symmetries by means of ortho-positronium decays…
Positronium is the simplest bound state, built of an electron and a positron. Studies of positronium in vacuum and its decays in medium tell us about Quantum Electrodynamics, QED, and about the structure of matter and biological processes…
The Jagiellonian Positron Emission Tomograph (J-PET) was constructed as a prototype of the cost-effective scanner for the simultaneous metabolic imaging of the whole human body. Being optimized for the detection of photons from the…
I briefly review Non-Relativistic QCD and related effective theories, and discuss applications to heavy quarkonium decay, and production in electron-positron colliders.
A first result related to a CPT test in the decay of ortho-positronium based on data collected by means of the J-PET detector is already available, and a new test of CP symmetry is under investigation. Both results are based on the…
We present a brief overview of precision tests of bound state QED and mainly pay our attention to laser spectroscopy as an appropriate tool for these tests. We particularly consider different precision tests of bound state QED theory based…
Positronium annihilation amplitudes that are computed by assuming a factorization approximation with on-shell intermediate leptons, do not exhibit good analytical behavior. We propose an ansatz which allows to include binding energy…
We present the first calculation of QED radiative corrections to deep-inelastic electron-photon scattering in terms of those variables that are reconstructed in measurements of the photon structure function in electron-positron collisions.…
An effective theory of the excited states of positronium is derived and some of its consequences are explored. At large physical separation, the binding of the electron and positron is assumed to be described completely by QED, whereas all…