Anti-electron

The hole theory was perceived as a Active mathematical construction and was initially rejected by prominent contemporary physicists such as Pauli and Bohr. The physical reality of antiparticles was not taken seriously even by Dirac himself. In 1931 he wrote about his anti-electron we should not expect to find it in Nature [2]. Surprisingly, the first anti-electrons were discovered already in 1932 by Anderson, who studied cosmic rays in Caltech s magnet cloud chamber. Anderson noticed abnormally bending trajectories indicating the presence of light positively charged particles and, as related by Fowler [3], "could not resist the devastating conclusion that they are caused by positive electrons The first piece of antimatter, a positron, made its physical appearance. 

The first anti-particle discovered was the anti-electron, the so-called positron, in 1933 by Anderson [3] in the cloud chamber due to cosmic radiation. The existence of the anti-electron (positron) was described by Dirac s hole theory in 1930 [4], The result of positron—electron annihilation was detected in the form of electromagnetic radiation [5]. The number and event of radiation photons is governed by the electrodynamics [6, 7]. The most common annihilation is via two- and three-photon annihilation, which do not require a third body to initiate the process. These are two of the commonly detected types of radiation from positron annihilation in condensed matter. The cross section of three-photon annihilation is much smaller than that of two-photon annihilation, by a factor on the order of the fine structure constant, a [8], The annihilation cross section for two and three photons is greater for the lower energy of the positron—electron pair it varies with the reciprocal of their relative velocity (v). In condensed matter, the positron—electron pair lives for only the order of a few tenths to a few nanoseconds against the annihilation process. 

Special Topic 11.1 describes anti-particles, such as anti-electrons (positrons). Every particle has a twin anti-particle that formed along with it from very concentrated energy. When a particle meets an antimatter counterpart, they annihilate each other, leaving pure energy in their place. For example, when a positron collides with an electron, they both disappear, sending out two gamma (y) photons in opposite directions. 

Positron A high-velocity anti-electron released from radioactive nuclides that have too few neutrons. 

In 1996 physicists created an anti-atom of hydrogen. In such an atom, which is the antimatter equivalent of an ordinary atom, the electrical charges of all the component particles are reversed. Thus the nucleus of an anti-atom is made of an anti-proton, which has the same mass as a proton but bears a negative charge, while the electron is replaced by an anti-electron (also... 

All the particles in Table 10.1 have spin. Quantum mechanical calculations and experimental observations have shown that each particle has a fixed spin energy which is determined by the spin quantum number s s = h for leptons and nucleons). Particles of non-integral spin are csWeA fermions because they obey the statistical rules devised by Fermi and Dirac, which state that two such particles cannot exist in the same closed system (nucleus or electron shell) having all quantum numbers the same (referred to as the Pauli principle). Fermions can be created and destroyed only in conjunction with an anti-particle of the same class. For example if an electron is emitted in 3-decay it must be accompanied by the creation of an anti-neutrino. Conversely, if a positron — which is an anti-electron — is emitted in the ]3-decay, it is accompanied by the creation of a neutrino. 

The anti-electron was indeed detected in 1932 by the American physicist Carl David Anderson (1905- ), in his study of cosmic rays. When... 

The anti-proton defied detection for another quarter-century. Since the anti-proton is 1836 times as massive as the anti-electron, 1836 times as much energy is required for its formation. The necessary energies were not created in manmade devices until the 1950s. Using huge accelerators, the Italian-American physicist Emilio Segre (1905- ) and... 

Positron -tl 1/1836 Fast anti-electrons emitted from radioactive materials... 

Historically, synchrotron radiation sources were associated with particle accelerators constructed for high energy physics experiments - so-called first generation sources. Electrons or positrons (anti-electrons) are accelerated in a closed orbit through an evacuated pipe at speeds exceedingly close to the speed of light ... 

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