Illustration of electric charge of particles (left) and antiparticles (right). From top to bottom; electron/positron, proton/antiproton, neutron/antineutron.
Antimatter
Antiparticles
Positron
Antiproton
Antineutron
Antihydrogen
Antihelium
Onia
Antiprotonic hydrogen
Antiprotonic helium
Muonium
True muonium
Pionium
Positronium
Quarkonium
Concepts and phenomena
Annihilation
Baryogenesis
Baryon asymmetry
Comet
CP violation
Gravitational interaction
Positron emission
Devices
Cloud chamber
Particle accelerator
Antiproton decelerator
Relativistic Heavy Ion Collider
Penning trap
Uses
Positron emission tomography
Fuel
Weapon
People and bodies
Carl David Anderson
Paul Dirac
Andrei Sakharov
CERN
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In particle physics, every type of particle of "ordinary" matter (as opposed to antimatter) is associated with an antiparticle with the same mass but with opposite physical charges (such as electric charge). For example, the antiparticle of the electron is the positron (also known as an antielectron). While the electron has a negative electric charge, the positron has a positive electric charge, and is produced naturally in certain types of radioactive decay. The opposite is also true: the antiparticle of the positron is the electron.
Some particles, such as the photon, are their own antiparticle. Otherwise, for each pair of antiparticle partners, one is designated as the normal particle (the one that occurs in matter usually interacted with in daily life). The other (usually given the prefix "anti-") is designated the antiparticle.
Particle–antiparticle pairs can annihilate each other, producing photons; since the charges of the particle and antiparticle are opposite, total charge is conserved. For example, the positrons produced in natural radioactive decay quickly annihilate themselves with electrons, producing pairs of gamma rays, a process exploited in positron emission tomography.
The laws of nature are very nearly symmetrical with respect to particles and antiparticles. For example, an antiproton and a positron can form an antihydrogen atom, which is believed to have the same properties as a hydrogen atom. This leads to the question of why the formation of matter after the Big Bang resulted in a universe consisting almost entirely of matter, rather than being a half-and-half mixture of matter and antimatter. The discovery of charge parity violation helped to shed light on this problem by showing that this symmetry, originally thought to be perfect, was only approximate. The question about how the formation of matter after the Big Bang resulted in a universe consisting almost entirely of matter remains an unanswered one, and explanations so far are not truly satisfactory, overall.
Because charge is conserved, it is not possible to create an antiparticle without either destroying another particle of the same charge (as is for instance the case when antiparticles are produced naturally via beta decay or the collision of cosmic rays with Earth's atmosphere), or by the simultaneous creation of both a particle and its antiparticle (pair production), which can occur in particle accelerators such as the Large Hadron Collider at CERN.
Particles and their antiparticles have equal and opposite charges, so that an uncharged particle also gives rise to an uncharged antiparticle. In many cases, the antiparticle and the particle coincide: pairs of photons, Z0 bosons, π0 mesons, and hypothetical gravitons and some hypothetical WIMPs all self-annihilate. However, electrically neutral particles need not be identical to their antiparticles: for example, the neutron and antineutron are distinct.
associated with an antiparticle with the same mass but with opposite physical charges (such as electric charge). For example, the antiparticle of the electron...
process that occurs when a subatomic particle collides with its respective antiparticle to produce other particles, such as an electron colliding with a positron...
In modern physics, antimatter is defined as matter composed of the antiparticles (or "partners") of the corresponding particles in "ordinary" matter,...
muon neutrino, tauon and tauon neutrino), along with the corresponding antiparticle of each of these. Mathematically, there are many varieties of fermions...
matter that is composed of the antiparticles of those that constitute ordinary matter. If a particle and its antiparticle come into contact with each other...
mass 493.677±0.013 MeV and mean lifetime (1.2380±0.0020)×10−8 s. K+ (antiparticle of above) positively charged (containing an up quark and a strange antiquark)...
Particles have corresponding antiparticles with the same mass but with opposite electric charges. For example, the antiparticle of the electron is the positron...
(the same as the electron), and the same mass as an electron. It is the antiparticle (antimatter counterpart) of the electron. When a positron collides with...
General antiparticle spectrometer (GAPS) is a planned experiment that will use a high-altitude balloon flying in Antarctica to look for antideuteron particles...
fermion is a spin-½ particle (a fermion) which is different from its antiparticle. A vast majority of fermions fall under this category. In particle physics...
also Dirac fermions; that is, each known fermion has its own distinct antiparticle. It is not known whether the neutrino is a Dirac fermion or a Majorana...
neutrinos. For every lepton flavor, there is a corresponding type of antiparticle, known as an antilepton, that differs from the lepton only in that some...
rays. Photons can also be emitted when a particle and its corresponding antiparticle are annihilated (for example, electron–positron annihilation).: 572, 1114...
also referred to as a Majorana particle, is a fermion that is its own antiparticle. They were hypothesised by Ettore Majorana in 1937. The term is sometimes...
containing bottom quarks include: B mesons contain a bottom quark (or its antiparticle) and an up or down quark. B c and B s mesons contain a bottom quark along...
gravitation, electromagnetism, weak interactions, and strong interactions. The antiparticle of the up quark is the up antiquark (sometimes called antiup quark or...
energy and time, a single photon can briefly form a virtual particle-antiparticle pair, that influences the point charge. This effect is called vacuum...
accelerators). For every quark flavor there is a corresponding type of antiparticle, known as an antiquark, that differs from the quark only in that some...
gravitation, electromagnetism, weak interactions, and strong interactions. The antiparticle of the strange quark is the strange antiquark (sometimes called antistrange...
electron neutrino. For each neutrino, there also exists a corresponding antiparticle, called an antineutrino, which also has spin of 1 /2 and no electric...
spectroscopy for the photon radiation produced when a particle and its antiparticle collide and annihilate. Most commonly, this refers to 511-keV photons...
fermionic antiparticles that correspond to these 12 particles. For example, the antielectron (positron) e+ is the electron's antiparticle and has an...
own antiparticle. In other words, it remains itself under the charge conjugation, which replaces particles with their corresponding antiparticles. All...
identified as the muon neutrino. The electron neutrino has a corresponding antiparticle, the electron antineutrino ( ν e), which differs only in that some of...
antiquark's baryon numbers cancel. Each type of baryon has a corresponding antiparticle (antibaryon) in which quarks are replaced by their corresponding antiquarks...
Pair production is the creation of a subatomic particle and its antiparticle from a neutral boson. Examples include creating an electron and a positron...
C {\displaystyle {\mathcal {C}}} that transforms a particle into its antiparticle, C | ψ ⟩ = | ψ ¯ ⟩ . {\displaystyle {\mathcal {C}}\,|\psi \rangle =|{\bar...
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