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Elementary Particles and Interactions — Overview
Published in K Grotz, H V Klapdor, S S Wilson, The Weak Interaction in Nuclear, Particle and Astrophysics, 2020
K Grotz, H V Klapdor, S S Wilson
For every particle, i.e. for each of the elementary fermions referred to above, there exists an antiparticle. This has the same mass, spin, isospin and eigenparity as the particle, and if the particle is unstable, the antiparticle has the same lifetime. It differs from the particle in the sign of its electric charge, and in the signs of all its other additive quantum numbers (see Section 1.3). That antiparticles with these properties must exist is a fundamental result of relativistic quantum field theory. The notation for antiparticles is not uniform. The antiparticle of any fermion f may be unambiguously denoted by fC. The ‘C’ stands for ‘charge conjugation’, this terminology reflects the change in the sign of the charge on transition to the antiparticle. However, this notation is not used very often. The charge conjugation operation effects the transition to an antiparticle state; however care is needed if the state of motion of the particle has a role to play, as with the neutrino (see Subsections 1.3.8 – 1.3.10).
Radioactivity and Matter
Published in Ivan G. Draganić, Zorica D. Draganić, Jean-Pierre Adloff, Radiation and Radioactivity on Earth and Beyond, 2020
Ivan G. Draganić, Zorica D. Draganić, Jean-Pierre Adloff
When an antiparticle collides with its corresponding particle, they both disappear and their masses are transformed into energy. The annihilation of an electron and a positron releases energy which is twice the mass of electron, or 2×0.511=1.022MeV. The energy of annihilation radiation in the event of a proton-antiproton collision is about 2000 times higher because of the correspondingly larger masses involved in the process. The products of annihilation reactions are photons, particles, and antiparticles. Today it is possible to create and examine antimatter particles in the laboratory in the same manner as for their material counterparts.
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Published in Philip A. Laplante, Comprehensive Dictionary of Electrical Engineering, 2018
anticomet tail (ACT) antiparticle a particle having the same mass as a given fundamental particle, but whose other properties, while having the same magnitude, may be of opposite sign. Each particle has a partner called an antiparticle. For example, electrical charge in the case of the electron and positron, magnetic moment in the case of the neutron and antineutron. On collision a particle and its antiparticle may mutually annihilate with the emission of radiation. Some properties of the antiparticle will be identical in magnitude but opposite in sign to the particle it is paired with.
Coexistence of positive and negative polarity solitons, double layers and supersolitons in electron-positron multi-ion plasmas
Published in Waves in Random and Complex Media, 2023
Debaditya Kolay, Debjit Dutta, Biswajit Sahu
The plasmas that have positrons act differently than usual plasma containing ions and electrons. The positrons are produced by the interplay of atoms and cosmic ray nuclei in the interstellar medium [1,2]. So in nature electron-positron-ion plasma appear in the early universe [3,4], pulsar magnetosphere [5], active galactic nuclei [6], neutron stars [7,8]) and solar atmosphere [9] etc. The electron's anti-particle is a positron that is positively charged and has equal mass and magnitude of charge as the electron. In very early universe [3,4] (when the temperature was nearly ), due to high temperature, photons had enough energy to produce electron-positron pairs. To be more precise, during the first second after the big-bang a huge number of electron-positron pair is created maintaining thermodynamic equilibrium. The electron-positron pair comes into exist in active galactic nuclei [6], when the gamma ray with energy interacts with soft photons of energy . In neutron star [7,8], the electron-positron pairs are formed during the magnetosphere filling period through curvature radiation which supplies electron-positron pairs to the neutron star's surroundings. In their paper, Dwyer et al. [10] suggested that the Earth's inner magnetosphere could be a new source of highly energetic electrons and positrons. According to new data from the Ramaty High Energy Solar Spectroscopic Imager (RHESSI), the Sun can emit positrons under specific circumstances, and solar flare-induced plasma collisions near the surface can provide enough energy to produce positron-electron pairs [11]. According to Greaves et al. [12], the modified positron trapping method have produced room-temperature plasmas containing positrons with s lifespan. Thus, majority of astrophysical and laboratory plasmas end up being an amalgam of electrons, positrons, and ions due to the long lifespan of positrons. Consequently, the e-p-i plasma has recently gained interest among plasma physicists.