The%202004%20Nobel%20Prize%20in%20Physics

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The 2004 Nobel Prize in Physics

• Sourendu Gupta (TIFR)
• St. Xaviers College, 6/1/2005

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The people

• David J. Gross
• Kavli Institute of Theoretical Physics
• University of California at Santa Barbara
• USA
• (b. 1941)

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The people

• H. David Politzer
• California Institute of Technology
• USA
• (b. 1949)

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The people

• Frank Wilczek
• Massachusetts Institute of Technology
• USA
• (b. 1951)

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The prize

• for the discovery of asymptotic freedom in
  strong interactions

1,300,000
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The work

• Gross and Wilczek, Ultraviolet behaviour of
  non-Abelian gauge theories, Physical Review
  Letters, vol 30, p 1343-1346, 1973
• Politzer Reliable perturbative results for
  Strong Interactions?, Physical Review Letters,
  vol 30, p 1346-1349, 1973

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Nobel Prizes for theStrong Interactions

• 2004 Gross, Politzer, Wilczek
• 1990 Friedman, Kendall, Taylor (DIS)
• 1982 Kenneth G. Wilson (RG/LGT)
• 1976 Richter, Ting (J/?)
• 1969 Murray Gell-Mann (quark model)
• 1968 Luis Alvarez (hadrons)

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The two arms of physics

• Variables what are the things that make up what
  we study analysis
• Dynamics how do the variables interact and move
  .synthesis

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Elementary Particles variables

• 1895 e
• 1935 e,p,n,?,?
• Who ordered that? - Rabi
• 1950 e,p,n,?,?,?,?,?,?,?,?
• Had I foreseen that, I would have
  gone into botany - Fermi

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QED

• Variables are e, ?, ?, ?
• Dynamics is Maxwells dynamics with quantization
  Dirac, Heisenberg, Bethe (1930s)
• Theory solved in the 40s (Feynman, Schwinger,
  Tomonaga)
• Very successful in describing experiments

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Quantum Hadron Dynamics?

• Theory of meson baryon interactions was in a
  mess.
• Yukawa theory (1932)
• 1960s S-matrix, dual resonance, Regge, string
  theory.
• Variables were wrong, the dynamics was premature

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The Eightfold Way (variables)

• The periodic table of hadrons
• Building block of hadrons are quarks
• Mesons contain a quark and an anti-quark, baryons
  have 3 quarks
• Masses of hadrons are predictions
• Gell-Mann, Zweig, Nishijima (1953)

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The Eightfold Way (variables)
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The Eightfold Way (variables)
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The Eightfold Way (variables)
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The Eightfold Way (variables)
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The era of massive confusion

• Quark search experiments failed.
• Idea of confinement quarks live only inside
  hadrons
• Colour Nambu, Fritzsch, Gell-Mann

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The crucial experiment

• Deep inelastic scattering- the Rutherford
  experiment of particle physics
• First view of quarks
• Friedman, Kendall, Taylor (1969)
• Bjorken, Feynman

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Particles in the Standard Model (1990s)
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Quantum Chromo-Dynamics the dynamics ofquarks
and gluons
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Screening in a plasma
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Effective charge

• A modification to Coulombs law is the same as a
  distance dependent charge renormalization

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The bubbling vacuum

• Quantum fluctuations ????t lt h/2?
• Particles can be produced from vacuum for a short
  time
• In a quantum field theory the vacuum bubbles over
  with particles
• Since it has mobile charges, the vacuum screens

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Charge renormalization screening in QED
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Anti-screening in QCD

• Asymptotic freedom is anti-screening the
  opposite of electrodynamics

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QCD is born (SLAC to LEP)

• Asymptotic freedom allowed computation of
  deep-inelastic cross sections, predicted lepton
  pair production, jets, etc
• many physicists
• (1970s to 1990s)

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Open problems for you

• Does anti-screening in vacuum become screening in
  matter?
• Are there new phases of matter in xxtreme
  conditions, like a QCD plasma?
• Relativistic heavy-ion collisions and LGT

• At long distances charge grows does confinement
  follow?
• Are there glueballs? New 5q or 6q states?
• Why is a proton so heavy?
• Lattice gauge theory

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Where it all connects

• High temperature matter early in the history of
  the universe
• High density matter in neutron stars and other
  supernova remnants

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The RHIC at Brookhaven
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The CRAY in TIFR
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Thank You
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How good is QCD?
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How good is QCD?