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Re: GRAVITONS (reply To Follow-up Of William Gunn)
Forum List | Follow Ups | Post Message | Back to Thread Topics | In Response To Posted by Fabian Helms/">Fabian Helms on September 28, 1999 17:13:30 UTC |
A graviton is definitely a boson which means that its spin quantum is expressed as a whole number (0,1,2...). Mostly it's assumed to carry a spin of 0. These particles - bosons - are obviously exchange quanta of the four basic forces (strong and weak nuclear force, electromagnetic force, gravity). Anti-particles of the known basic bosons (photons, gluons, w- and z-bosons) do not fit into the common (GUT-based) theories and hypotheses - as far as I know them. The other big class of basic particles - the fermions - contain their own anti-particles as a subset. Their spin is counted as half units (1/2, 3/2...). They divide into three families with growing masses and decreasing stabilities. Each family consists of a neutral and a charged lepton as well as two quarks which occur in three different "colors". The first family's members are the up- and down-quarks, the electron and the e-neutrino AS WELL AS THEIR ANTI-PARTICLES. In opposite to the bosons fermions accomplish the "Pauli exclusion principle" which doesn't allow two related fermions of the same kind to occupy the same quantum properties (energy, charge, and spin). So the fermion matter has the tendency to spread while bosons can easily be concentrated as bundles or rays. To make it even more confusing, other - fermion composed - particles can be considered as bosons. Examples are pions or kaons which consist of two quarks and a "lake" of corresponding gluons. Addition of all the spin quantum numbers within the pion or kaon always results in whole numbers (because of the two quarks which compensate their half spins). Last related item is the theory of super-symmetry which states that there is a corresponding partner boson for every fermion and vice versa. A graviton would be related to a hypothetical fermion called "gravitino" which WOULD have a corresponding anti-particle. If nature turns out to be that way the fermion families will have to be completed - and I know some mathematicians who would feel very uncomfortable. The basics of group theory and string theories which lead to this hypothesis are a bit too extended to be resumed here (and should better be explained by a physicist - not an amateur like me). |
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