hadron

hadron - any elementary particle that interacts strongly with other particles
Any particle that participates in the strong interactions.

One prominent representative of the lepton species, which comes in three families, each with an electrically charged lepton and a neutral neutrino, is the electron. It is known to play the all-important role in chemical and electrical phenomenoa. According to present-day knowledge, the leptons are elementary, i.,. are indivisible and have no substructure.

The proton (and neutron), i.e., nuclear matter, on the other hand, has been shown to be composed of more elementary units, the quarks. Supposedly six different kinds of quarks exist, again grouped in three families, in complete symmetry to the leptons. Five of these quarks have been found, and recent experimental evidence exists for the sixth quark. Only the two members of the first family are needed for "ordinary" nuclear matter, the "u" and the "d" quark. However, the quarks seem to always be bound together to form the nuclear particles, called hadrons, and never have been observed as free particles: Three such quarks make up the proton, two u quarks and one d quark, while the neutron consists of one u quark and two d quarks.

Figure 4.14 - Feynman's Triplet Structures of the proton and neutron. (from QED)
(click to enlarge)


See Also

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Atomic Triplet
Figure 1.9 - Keelys Molecular Morphology
Figure 4.12 - Keelys Formative Structural Dynamic Morphology
Figure 7.6 - Keelys Triune Morphology
Figure 7.7 - Keelys Morphology - Infinite Subdivision of Matter
Hadron
Quark
Table 15.02 - Triune Polar Streams
triune polar flows
Triune States of Matter and Energy


Hadrons containing the heavier quarks, s, c, and b have also been observed. These particles, however, have very short lifetimes and are being produced under "natural" condition[s] mostly in reactions of cosmic rays with nuclei in the terrestrial atmosphere. (Trefil, James S.; From Atoms to Quarks - An Introduction to the Strange World of Particle Physics; Charles Scribner's Sons, New York, 1980)

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