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The Story of Quarks the first two, then three…eventually 6…quarks or partons

The Story of Quarks the first two, then three…eventually 6…quarks or partons all hadrons made up of quarks to “explain” their quantum numbers …partons to describe their scattering behavior. bubble chamber recordings all “strange” particles made in association with each other

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The Story of Quarks the first two, then three…eventually 6…quarks or partons

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  1. The Story of Quarks the first two, then three…eventually 6…quarks or partons all hadrons made up of quarks to “explain” their quantum numbers …partons to describe their scattering behavior

  2. bubble chamber recordings all “strange” particles made in association with each other …they come in pairs invent a new “charge,” strange charge that is conserved …see how the Λgot its name

  3. Discovery of the Omega- Fig 46-11a, p.1528

  4. the octets of the Eightfold Way… spin = ½ = ↑↑↓ spin = 0 = ↑↓ B=1 baryons, “nucleon-like” B=0, mesons, “generalized pions” bary = heavy, > 1 GeV meso = medium weight, 0.1 -0.5 GeV Q = charge, S = strangeness really nonets and decuplets

  5. the excited nucleon, the Δ++ resonance…width  lifetime

  6. the hunt for the omega minus…spin = 3/2 = ↑↑↑ B=1 …the decuplet doubly charged ↓ family of 4 excited → nucleons Ω-

  7. some examples:

  8. all conceivable combinations of quark & antiquark found…and nothing else

  9. all conceivable combinations of 3 quark found…and nothing extra

  10. in the end, 6 quarks discovered…the t (top) only a few years ago

  11. we study the point-like electron with point-like neutrinos

  12. +2/3 probing the quarks with point-like neutrino …behave identically as electrons W+ -1/3

  13. individual current quarks inside composite particle scatter

  14. remaining mystery …the problem of mass: if you scatter quarks with electrons or neutrinos, you get mu ~ 5 MeV, md ~ 7 MeV, …the vast majority of the momentum is carried by gluons! naively dividing the rest mass of the composite particles among quark constituents, you get much different rest energies:

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