If you wish to view a bunch of antiparticles, your best bet is to produce them yourself. The positron, however, is a stranger in a strange land, and is quickly annihilated like a German tourist in Miami. When a gamma ray passes through a metal, for example, and produces an electron and a positron, the electron is quite at home amongst its fellow electrons in the metal. And cosmic rays are high energy particles or antiparticles from outer space.Īntiparticles do not usually last very long. A gamma ray (high energy photon) when going through material may convert its energy to an electron-positron pair via mc2 = E. You can also get positrons from radioactive decay such as carbon-11 –> boron-11 + positron + neutrino (beta+ decay). For instance, fusion processes in the sun produce scads of positrons (e.g., helium-3 + proton –> helium-4 + positron + neutrino). But what about pions? The pion+ is equal and opposite to the pion-, but which is the matter and which is the antimatter? For physicists, it doesn’t really matter (uh, no pun intended), each is the antiparticle of the other.Ģ) When a particle and its equal and opposite antiparticle get together, all the additive quantum numbers add to 0 and they annihilate, giving up both their masses into energy, via E = mc2.Īntiparticles do indeed exist in nature, mostly freshly produced in processes associated with radiation or radioactivity. Since the universe is composed of electrons, protons, and neutrons, we think of those as the matter, and positrons, antiprotons, and antineutrons as antimatter. Antimatter is equal and opposite to matter matter is equal and opposite to antimatter. A proton has charge +1 and baryon number +1, etc., and an antiproton has charge -1 and baryon number -1, etc.ġ) You cannot define antimatter without the context of matter. The positron (=antielectron) has electric charge quantum number +1 and fermion number -1, etc. For instance, an electron has electric charge quantum number -1 and fermion number +1, etc. in antimatter.Īntimatter is composed of particles which are identical to matter particles except that their additive quantum numbers have opposite sign. When I get done, you’ll have a freaking Ph.D.
ANTIMATTER FULL
Dear Straight Dope: What is antimatter? Does it occur naturally? If not, then how was it discovered? Did some scientist say, “I think that there is a such thing as antimatter” and then prove it? -Davidįinally! A question that requires the full power of a penguinist.
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