I’m ever curious (and I forget things quickly), so I thought I’d look up some information on string theory, but I got stuck in the world of quarks (a quagmire of information), so string theory will have to wait for another day…
The following is what I understood of the theory of quarks (illustration found Here):
Quarks — along with leptons (six of them: the electron, muon, tau, and their associated neutrinos) — are thought to be the elementary particles, the building blocks that matter is made of.
Quarks come in six flavors (three pairs): up and down, charm and strange, and top and bottom. The flavor identifies the quark’s properties (the different leptons are also referred to as flavors, and the three types of lepton (with their associated neutrino) are referred to as generations).
Quarks are not observed alone in nature: three quarks combine to make a baryon (e.g.: protons and neutrons, which are built from up and down quarks), and two quarks combine to create a meson (a quark-antiquark pair that is unstable). The up and down quarks are the most stable and common in our universe, and are named after their up and down isospin; strange quarks are components of the previously discovered ‘strange particles’ in cosmic radiation (they have unusually long life-times for their type); the charmed quark was so named because theorists “…were fascinated and pleased by the symmetry brought to the sub-nuclear world” (Attributed to James Daniel Bjorken in The Hunting of the Quark: A True Story of Modern Physics, by Michael Riordan); and top and bottom are “…logical partners for up and down quarks” (Haim Harari).
Each of the six flavors of quarks comes in three colors (which identify color charge and have nothing to do with color, but allows for three differing quantum states: red, blue, and green; which, when combined, give white). The concept of color is used because all observed particles have either three quarks (baryons) or two quarks (mesons), with combinations which can be ‘colorless’ or ‘color neutral’ using the three values of color (in nature, matter is ‘colorless’).
And I don’t think I’ve mentioned bosons yet (the virtual (guage) bosons are force carriers: photons for the electromagnetic field; the W and Z bosons for the weak force of radioactive decay; the gluons for the strong force of nuclear binding; and the long-searched-for graviton, the postulated force carrier of gravity), but that’s enough theory for me today…if you’re thirsty for more, a good place to start looking is HERE.
The odd nomenclature associated with quarks started with Murray Gell-Mann (who, along with George Zweig, co-proposed the quark theory). Gell-Mann discovered the word in a James Joyce novel:
“Three quarks for Muster Mark!
Sure he has not got much of a bark
And sure any he has it’s all beside the mark.”
(Finnegans Wake, Book 2, Episode 4, page 383 in my copy)
Gell-Mann further described his choice for the spelling of quark in The Quark and the Jaguar (p. 180):
“In 1963, when I assigned the name “quark” to the fundamental constituents of the nucleon, I had the sound first, without the spelling, which could have been “kwork”. Then, in one of my occasional perusals of Finnegans Wake, by James Joyce, I came across the word “quark” in the phrase “Three quarks for Muster Mark”. Since “quark” (meaning, for one thing, the cry of the gull) was clearly intended to rhyme with “Mark”, as well as “bark” and other such words, I had to find an excuse to pronounce it as “kwork”. But the book represents the dream of a publican named Humphrey Chimpden Earwicker. Words in the text are typically drawn from several sources at once, like the “portmanteau” words in “Through the Looking-Glass”. From time to time, phrases occur in the book that are partially determined by calls for drinks at the bar. I argued, therefore, that perhaps one of the multiple sources of the cry “Three quarks for Muster Mark” might be “Three quarts for Mister Mark”, in which case the pronunciation “kwork” would not be totally unjustified. In any case, the number three fitted perfectly the way quarks occur in nature.”
George Zweig preferred the name ace, but Gell-Mann’s name stuck.