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Quarks

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The document discusses the four fundamental particles that make up all ordinary matter - up quarks, down quarks, strange quarks, and charm quarks. Murray Gell-Mann named quarks after a line in James Joyce's book "Finnegan's Wake" and received the 1969 Nobel Prize for his work classifying elementary particles. As particle accelerators achieve higher energies, they can probe matter at finer scales and produce more massive objects via E=mc^2, leading to the discoveries of heavier quarks like bottom and top quarks.

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Quarks
We are made of particles and so is everything else in the universe! We know now that just four kinds of building blocks are needed to account for all of ordinary matter. These particles are called:
The name "quark" was taken by Murray Gell- Mann from the book "Finnegan's Wake" by James Joyce. The line "Three quarks for Muster Mark..." appears in the fanciful book. Gell- Mann received the 1969 Nobel Prize for his work in classifying elementary particles.
Quarks
As we go to higher energy particle collisions: 1) Wavelength probe is smaller  see finer detail 2) Can produce more massive objects, via E=mc2 Today, high energy accelerators produce energetic beams which allow us to probe matter at its most fundamental level
Quarks
Quark Date Where Mass [GeV/c2] Comment up, down - - ~0.005, ~0.010 Constituents of hadrons, most prominently, proton and neutrons. strange 1947 - ~0.2 discovered in cosmic rays charm 1974 SLAC/ BNL ~1.5 Discovered simultaneously in both pp and e+e- collisions. bottom 1977 Fermi- lab ~4.5 Discovered in collisions of protons on nuclei top 1995 Fermi- lab ~175 Discovered in pp collisions Notice the units of mass !!! SLAC = Stanford Linear Accelerator BNL = Brookhaven National LabProton mass = 0.938 [GeV/c2]
 6 different kinds of quarks.  Matter is composed mainly of up quarks and down quarks bound in the nuclei of atoms.  The masses vary dramatically (from ~0.005 to 175 [GeV/c2])  The heavier quarks are not stable, and decay to lighter quarks quite rapidly
1.25 miles Main Injector Tevatron Experimental areas Top Quark discovered here at FNAL in 1995.
~ 6 ft
• Pros –Explains zoo of hadrons economically –Verified by high energy electron scattering experiments • Cons –Isolated quarks have never been seen –No explanation for qqq=baryon & qq = meson rule –Problems with Pauli exclusion principle
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Quarks

  • 2. We are made of particles and so is everything else in the universe! We know now that just four kinds of building blocks are needed to account for all of ordinary matter. These particles are called:
  • 3. The name "quark" was taken by Murray Gell- Mann from the book "Finnegan's Wake" by James Joyce. The line "Three quarks for Muster Mark..." appears in the fanciful book. Gell- Mann received the 1969 Nobel Prize for his work in classifying elementary particles.
  • 5. As we go to higher energy particle collisions: 1) Wavelength probe is smaller  see finer detail 2) Can produce more massive objects, via E=mc2 Today, high energy accelerators produce energetic beams which allow us to probe matter at its most fundamental level
  • 7. Quark Date Where Mass [GeV/c2] Comment up, down - - ~0.005, ~0.010 Constituents of hadrons, most prominently, proton and neutrons. strange 1947 - ~0.2 discovered in cosmic rays charm 1974 SLAC/ BNL ~1.5 Discovered simultaneously in both pp and e+e- collisions. bottom 1977 Fermi- lab ~4.5 Discovered in collisions of protons on nuclei top 1995 Fermi- lab ~175 Discovered in pp collisions Notice the units of mass !!! SLAC = Stanford Linear Accelerator BNL = Brookhaven National LabProton mass = 0.938 [GeV/c2]
  • 8.  6 different kinds of quarks.  Matter is composed mainly of up quarks and down quarks bound in the nuclei of atoms.  The masses vary dramatically (from ~0.005 to 175 [GeV/c2])  The heavier quarks are not stable, and decay to lighter quarks quite rapidly
  • 9. 1.25 miles Main Injector Tevatron Experimental areas Top Quark discovered here at FNAL in 1995.
  • 11. • Pros –Explains zoo of hadrons economically –Verified by high energy electron scattering experiments • Cons –Isolated quarks have never been seen –No explanation for qqq=baryon & qq = meson rule –Problems with Pauli exclusion principle