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A short-lived association of an electron and a positron bound together in a configuration resembling the hydrogen atom.


(Atomic Physics) physics a short-lived entity consisting of a positron and an electron bound together. It decays by annihilation to produce two or three photons
[C20: from positron + -ium]


(ˌpɒz ɪˈtroʊ ni əm)

a short-lived atomic system consisting of a positron and an electron bound together.
[1945; positron + -ium2]
References in periodicals archive ?
Suppose we start with an excited positronium state [[PSI].
22]Na radioisotopes, they produce Positronium (Ps), which is a positron, that is, the antimatter of an electron, combined with an electron, that is, annihilated free positrons [21, 22].
Among his topics are the diffraction of particles in polarized crystals, positronium and muonium spin rotation and oscillations, the phenomenon of time-reversal violating magnetic field generation by a static electric field and electric field generation by a static magnetic field, spin rotation of particles moving in bent crystals and measuring the magnetic moment of short-lived particles and nuclei, and synchrotron-type radiation processes in crystals and polarization phenomena accompanying them.
Physicists David Cassidy and Allen Mills first separated the positron from the electron in positronium so that this unstable system would resist annihilation long enough for the physicists to measure the effect of gravity on it.
Total and positronium formation cross sections for positron scattering from H2O and HCOOH;
Antimatter matter Physicists showed that positronium "atoms" consisting of an electron and a positron (the electron's antimatter counterpart), could bind together briefly to form positroninm molecules.
The aim of this special collection is to present recent progress made, and reflect current ideas, in research fields where positron and positronium are involved.
The latter case is manifested for example in positronium or meson where (though very unstable) matter and antimatter reside together as the unity of the opposites.
When constituent polymers are not miscible in molecular level, ihe interphases or interlaces between two phases will affect the positronium formation and annihilation probabilities.
Positron and positronium chemistry; 10; proceedings.
Washington, July 12 (ANI): Physicists at the University of California, Riverside have found a new way to create positronium, an exotic and short-lived atom that could help answer what happened to antimatter in the universe, and why nature favoured matter over antimatter at the universe's creation.
Unlike antihydrogen, however this unusual matter-antimatter hybrid, called positronium, is unstable.