the 2004 nobel prize in physics sourendu gupta (tifr) st. xavier’s college, 6/1/2005
TRANSCRIPT
The 2004 Nobel Prize in Physics
Sourendu Gupta (TIFR)
St. Xavier’s College, 6/1/2005
Nobel 2004, Sourendu Gupta, Xavier's College, 2005
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The people
David J. GrossKavli Institute of Theoretical Physics
University of California at Santa BarbaraUSA
(b. 1941)
Nobel 2004, Sourendu Gupta, Xavier's College, 2005
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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 Maxwell’s dynamics with quantization: Dirac,
Heisenberg, Bethe (1930s)Theory solved in the 40’s (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 quarksFriedman, Kendall, Taylor
(1969)
Bjorken, Feynman
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Particles in the Standard Model (1990s)
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Quantum Chromo-Dynamics: the dynamics of
quarks and gluons
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Screening in a plasma
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Effective charge
A modification to Coulomb’s law is the same as a distance dependent charge: renormalization
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The bubbling vacuum
Quantum fluctuations: t < h/2Particles 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?