Quarks were theorized in 1964 and experiementally verified in 1968. To say "invented" would be a misnomer.
This next part is a direct quote from the Wikipedia article titled "Quark" [ http://en.wikipedia.org/wiki/Quarks ]:
The quark model was independently proposed by physicists Murray Gell-Mann and George Zweigin 1964. There was little evidence for this model until 1968, when electron-proton scattering experiments indicated that the electrons were scattering off three point-like constituents inside the proton. All six flavors of quark have been observed, following the discovery of the top quark at Fermilab in 1995.
Neutrons consist of small particles, called "Quarks". Protons also consist of quarks, but what quarks is made of, is still not discovered.
In an atom, the neutrons and protons are made up of up quarks and down quarks. Strange quarks, charms quarks, top quarks, and bottom quarks also exist, but do not play as much of a role in the structure of an atom.
A proton contain 2 up quarks and 1 down quark; quarks are bonded by gluons.
The subatomic particles found in protons and neutrons are quarks. There are two types of quarks that combine to make either particle, up and down quarks. Protons are 2 ups and a down and neutrons are 2 downs and an up.
A mixture of down and up quarks and antiquarks. D-antiD, D-antiU, U-antiD, or U-antiU.
There are 6 different types of quarks, named in pairs:Top, BottomStrange, CharmUp, Down0123qwerty0123But don't forget that all particles, besides force particles ( gravity-graviton, electromagnetism-photon, weak force-low guage boson, strong force-gluon ), have antimatter counterparts.Anti-top, Anti-bottomAnti-strange, Anti-charmAnti-up, Anti-down
Protons and neutrons are composite particles make up of up and down quarks. There are two up quarks and one down quark in a proton, and two down quarks and an up quark in a neutron.
Quarks, gluons and gauge bosons are the simplest particles currently discovered.
Neutrons consist of small particles, called "Quarks". Protons also consist of quarks, but what quarks is made of, is still not discovered.
A proton is made up of two up quarks and one down quark.
There are six quarks, the up, down, charm, strange, top, and bottom quarks.
Three common quarks are up, down, and strange. Up and down quarks are found in protons and neutrons, while strange quarks are found in certain types of subatomic particles.
There are two up quarks and one down quark in one proton.
Up quarks and down quarks are in protons and neutrons.
Up quarks and down quarks are in protons and neutrons.
Protons and neutrons are made of smaller particles called quarks. Protons are composed of two up quarks and one down quark, while neutrons are composed of two down quarks and one up quark. These quarks are held together by the strong nuclear force.
The last quark to be discovered was the top quark in 1995 at Fermilab in the United States. It is the heaviest of all quarks and completes the six-member family of quarks.