How many subatomic particles are known to exist?

markswood

According to Wikipedia, dozens. Subatomic particles include the atomic constituents electrons, protons, and neutrons. Protons and neutrons are composite particles, consisting of quarks. A proton contains two up quarks and one down quark, while a neutron consists of one up quark and two down quarks; the quarks are held together in the nucleus by gluons. There are six different types of quark in all ('up', 'down', 'bottom', 'top', 'strange', and 'charm'), as well as other particles including photons and neutrinos which are produced copiously in the sun. Most of the particles that have been discovered are encountered in cosmic rays interacting with matter and are produced by scattering processes in particle accelerators. There are dozens of subatomic particles. Ref:http://en.wikipedia.org/wiki/Subatomic_particles Feb 02 08, 4:33 AM

zbeckabee

The last link (below) shows a complete list of ALL known subatomic particles. In 1940, the number of subatomic particles known to science could be counted on the fingers of one hand: protons, neutrons, electrons, neutrinos, and positrons. That view of matter changed dramatically over the next two decades. With the invention of particle accelerators (atom-smashers) and the discovery of nuclear fission and fusion, the number of known subatomic particles increased. Scientists discovered a number of particles that exist at energies higher than those normally observed in our everyday lives: sigma particles, lambda particles, delta particles, epsilon particles, and other particles in positive, negative, and neutral forms. By the end of the 1950s, so many subatomic particles had been discovered that some physicists referred to their list as a "particle zoo." In 1964, American physicist Murray Gell-Mann (1929– ) and Swiss physicist George Zweig (1937– )suggested that only a relatively few elementary particles existed, and the other subatomic particles that had been discovered were composed of various combinations of these truly elementary particles. http://www.scienceclarified.com/Sp-Th/Subatomic-Particles.html http://www.physics.adelaide.edu.au/cssm/overheads/MoreInfo.html Feb 02 08, 10:29 AM