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Particle Physics - Classification, 1 of 3 There are now more than 200 particles being discovered. Just like the periodic table in chemistry, these particles can also be classified in a systematic way. In fact, all matter of every types: be those seen in Earth, or outer space or those only exist in high energy conditions, are made of various combinations of twelve basic building blocks or fundamental particles. Together with the basic force carriers, these particle made up of all known matter. These fundamental particles are grouped according to the quark-lepton model: Quarks Generations Leptons + 2/3 u Up ~9 x 10-30 - 1/3 d Down ~1 x 10-29 First -1 e Electron 9.1 x 10-31 0 ne electron- neutrino < 2 x 10-35 + 2/3 c Charm ~3 x 10-27 - 1/3 s Strange ~3 x 10-28 Second -1 m Muon 1.9 x 10-28 0 nm muon- neutrino < 4 x 10-31 + 2/3 t Top ~3 x 10-25 - 1/3 b Bottom ~8 x 10-27 Third -1 t Tauon 3.2 x 10-27 0 nt tau- neutrino < 6 x 10-29 In addition to the above listed twelve fundamental particles there are also twelve corresponding antiparticles. They are the basic building blocks of antimatter which made up the anti-universe. Antiparticles are identical to particles, except the sign of the values change. For example, the electron has a charge -1, while the antiparticle counterpart is +1, and is called positron. Similarly, a proton is +1 while antiproton is -1. From the table it is shown that for each generation there is a pair of quarks and a pair of leptons. There is also an increase in mass as the generation is increased, which indicates an increase in energy for the matter to exist in a given generation. The first generation particles are responsible to make all the ordinary matter. From all the existing experimental evidence and observations of our present universe there is a strong indication that there is only three generations and the list shown above is complete. This fundamental model structure is known as the Standard Model. Notice the word Standard and it does not mean complete. More about the Standard Model will be discussed in the section Unification.

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