Related papers: Who discovered positron annihilation?
Dawning neutron physics was more complex than one might expect. The chance that the neutron comprised a proton and an electron was diffusely taken into account after the discovery of the neutron. Moreover, uncertainties persisted about the…
The annihilation of positrons in the Milky Way galaxy has been observed for $\sim 50$ years however the production sites of these positrons remains hard to identify. The observed morphology of positron annihilation gamma-rays provides…
We present evidence for small oscillations we observe in electron-positron and proton-antiproton annihilation data, with a periodicity of 76+-2 MeV, independent of the beam energy. We discuss some possible scenarios to explain the…
Annihilation of the electron-positron pairs in macroscopic polyelectrons is considered. It is shown that very fast collapse of the spatial area occupied by macroscopic polyelectron (or dense electron-positron plasma) produces an instant…
At the beginning of the twentieth century, two scientists, the Austrian Victor Hess and the Italian Domenico Pacini, developed two brilliant lines of research independently, leading to the determination of the origin of atmospheric…
Currently, forty-two thallium, forty-two lead, forty-one bismuth, and forty-two polonium isotopes have so far been observed; the discovery of these isotopes is discussed. For each isotope a brief summary of the first refereed publication,…
Positron and electron cosmic rays provide a complementary way to study the galactic environment. The actual cosmic rays experiments, for instance PAMELA and HEAT, have presented very exciting results in this field. The observed positron…
At the beginning of the twentieth century, two scientists, the Austrian Victor Hess and the Italian Domenico Pacini, developed two brilliant lines of research independently, leading to the determination of the origin of atmospheric…
A model-potential approach has been developed to study positron interactions with molecules. Binding energies and annihilation rates are calculated for positron bound states with a range of alkane molecules, including rings and isomers. The…
Bursts from the very early universe may lead to a detectable signal via the production of positrons, whose annihilation gives an observable X-ray signal. Using the absorption parameters for the annihilation photons of 511 keV, it is found…
Positron scattering and annihilation on noble gas atoms below the positronium formation threshold is studied ab initio using many-body theory methods. The many-body theory provides a near-complete understanding of the…
Preliminary results are presented from a new positron beam system currently under development at the University of Texas at Arlington for the coincident energy measurement of Doppler-shifted annihilation quanta and positron-induced Auger…
The concept of extremely dense matter at supra-nuclear density was first speculated by L. Landau in the beginning of 1930s when neutron was just discovered. A historical review on these issues not only explains the interaction between micro…
Positron physics touches on a wide-ranging variety of fields from materials science to medical imaging to high energy physics. In this paper we present the development of a flexible positron annihilation spectrometer appropriate for the…
Annihilation spectra are presented for aromatic and heterocyclic ring molecules resolved as a function of incident positron energy using a trap-based positron beam. Comparisons with the vibrational mode spectra yield positron-molecule…
Electron-positron annihilation largely occurs in local thermal and chemical equilibrium after the neutrinos fall out of thermal equilibrium and during the Big Bang Nucleosynthesis (BBN) epoch. The effects of this process are evident in BBN…
In the positron-electron annihilation process, finite deviations from the standard calculation based on the Fermi's Golden rule are suggested in recent theoretical work. This paper describes an experimental test of the predictions of this…
We report the first observation of the annihilation of positronium from the 2S state. Positronium (Ps) is excited with a two-photon transition from the 1S to the 2S state where its lifetime is increased by a factor of eight compared to the…
When Enrico Fermi discovered slow neutrons, he accounted for their great efficiency in inducing radioactivity by merely mentioning the well-known scattering cross-section between neutrons and protons. He did not refer to capture…
The positron-electron pair annihilation in two photons is known for its numerous applications using PET scanners. The decay of Positronium (Ps) from a standard sealed source in more than two photons is less likely but can be observed with a…