the 2004 nobel prize in physics sourendu gupta (tifr) st. xavier’s college, 6/1/2005

The 2004 Nobel Prize in Physics

Sourendu Gupta (TIFR)

St. Xavier’s College, 6/1/2005

Nobel 2004, Sourendu Gupta, Xavier's College, 2005

2

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

3

The people

H. David Politzer California Institute of Technology

USA(b. 1949)

Nobel 2004, Sourendu Gupta, Xavier's College, 2005

4

The people

Frank Wilczek Massachusetts Institute of Technology

USA(b. 1951)

Nobel 2004, Sourendu Gupta, Xavier's College, 2005

5

The prize

“for the discovery of asymptotic freedom in strong interactions”

$1,300,000

Nobel 2004, Sourendu Gupta, Xavier's College, 2005

6

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

Nobel 2004, Sourendu Gupta, Xavier's College, 2005

7

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)

Nobel 2004, Sourendu Gupta, Xavier's College, 2005

8

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

Nobel 2004, Sourendu Gupta, Xavier's College, 2005

9

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

Nobel 2004, Sourendu Gupta, Xavier's College, 2005

10

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

Nobel 2004, Sourendu Gupta, Xavier's College, 2005

11

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

Nobel 2004, Sourendu Gupta, Xavier's College, 2005

12

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)

Nobel 2004, Sourendu Gupta, Xavier's College, 2005

13

The Eightfold Way (variables)

Nobel 2004, Sourendu Gupta, Xavier's College, 2005

14

The Eightfold Way (variables)

Nobel 2004, Sourendu Gupta, Xavier's College, 2005

15

The Eightfold Way (variables)

Nobel 2004, Sourendu Gupta, Xavier's College, 2005

16

The Eightfold Way (variables)

Nobel 2004, Sourendu Gupta, Xavier's College, 2005

17

The era of massive confusion

Quark search experiments failed.

Idea of confinement: quarks live only inside hadrons

Colour: Nambu, Fritzsch, Gell-Mann

Nobel 2004, Sourendu Gupta, Xavier's College, 2005

18

The crucial experiment

Deep inelastic scattering- the ‘Rutherford experiment’ of particle physics

First view of quarksFriedman, Kendall, Taylor

(1969)

Bjorken, Feynman

Nobel 2004, Sourendu Gupta, Xavier's College, 2005

19

Particles in the Standard Model (1990s)

Nobel 2004, Sourendu Gupta, Xavier's College, 2005

20

Quantum Chromo-Dynamics: the dynamics of

quarks and gluons

Nobel 2004, Sourendu Gupta, Xavier's College, 2005

21

Screening in a plasma

Nobel 2004, Sourendu Gupta, Xavier's College, 2005

22

Effective charge

A modification to Coulomb’s law is the same as a distance dependent charge: renormalization

Nobel 2004, Sourendu Gupta, Xavier's College, 2005

23

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

Nobel 2004, Sourendu Gupta, Xavier's College, 2005

24

Charge renormalization: screening in QED

Nobel 2004, Sourendu Gupta, Xavier's College, 2005

25

Anti-screening in QCD

Asymptotic freedom is anti-screening: the opposite of electrodynamics

Nobel 2004, Sourendu Gupta, Xavier's College, 2005

26

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)

Nobel 2004, Sourendu Gupta, Xavier's College, 2005

27

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…

Nobel 2004, Sourendu Gupta, Xavier's College, 2005

28

Where it all connects

High temperature matter: early in the history of the universe

High density matter: in neutron stars and other supernova remnants

Nobel 2004, Sourendu Gupta, Xavier's College, 2005

29

The RHIC at Brookhaven

Nobel 2004, Sourendu Gupta, Xavier's College, 2005

30

The CRAY in TIFR

Nobel 2004, Sourendu Gupta, Xavier's College, 2005

31

Thank You

Nobel 2004, Sourendu Gupta, Xavier's College, 2005

32

How good is QCD?

Nobel 2004, Sourendu Gupta, Xavier's College, 2005

33

How good is QCD?