??????? Quarks and Asymptotic Freedom

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???????Quarks and Asymptotic Freedom

• ????? (Professor Ming-Chung Chu) ?????????????
• ????? (Professor Kenneth Young)
  ?????????????????????????
• 15/10/2004

2
2004 ??????

• "for the discovery of asymptotic freedom in the
  theory of the strong interaction"
• David Gross, David Politzer and Frank Wilczek
  discovered a property of the strong interaction
  which explains why quarks may behave almost as
  free particles only at high energies. The
  discovery laid the foundation for the theory for
  the colour interaction (a more complete name is
  Quantum ChromoDynamics, QCD).

3
??????? Quarks and Asymptotic Freedom

• ??????
• 1/3, 2/3 ????
• ??????
• ???????
• ??? ????
• ??? ????

4
I. ?????

• ??(quark)?????(strong force)
• ??????
• - 1.????(quark matter)
• - 2.???(strange star)

Ref. C. Quigg, Elementary Particles and
Forces, Scientific American April 1985, P. 64-75.
5
???????

• ????(strong force) ???????
• ?????nucleons(?????hadrons)?????,
  ???proton,??neutron , ? ??meson,K??,? ??????

?? (10-15 m),?(?ltlt ?? lt ? lt ?) ???? 10-40
10-2 0.3 1
coupling constant
Ref. Serway, Moses, Moyer, Modern Physics
(Saunders College Publishing, 1996)
D.H. Perkins, Introduction to High Energy
Physics (Addison-Wesley, 1982)
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??(hadron) ???????
????????????????????,??????????
?? ??(baryon) ?p, n???(meson) ??, K
http//hyperphysics.phy-astr.gsu.edu/hbase/particl
es/hadron.html
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???????

• ????????? (M. Gell-Mann G. Zweig, 1964)
• ?????????(flavors)
• u (? up) d (? down)
  c (? charm) s (?? strange) t (? top) b
  (? bottom/beauty)
• ??????????????
• ??????????10-18 m

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?????!

• ???????????
• ???????
• ?????????(colorless)?????

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???? (Quark Model)

• ???????????
  (??????????????)
• ???? (q q q) ??? (baryon) (q q ) ???
  (meson)
• ?? ??(proton) uud
• ??(neutron) udd
• ?? ( meson) ud
  K0 ?? ( K0 meson) ds

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?? Hadron (1)
??????
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???? Exotic baryon
???? Pentaquark m 1.5 GeV
??????2003???
http//www.aip.org/enews/physnews/2003/644.html
http//news.bbc.co.uk/1/hi/sci/tech/3034754.stm
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???? (Strong interaction) (1)

• ??????(gluon)
• ??????,???
• ????/????????,?

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???? (Strong interaction) (2)

• ??
• ??????

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???? (Strong interaction) (3)

• ????????
• ????
• ???????????,????????????????(color singlet)
  f 3/4?

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?? (2)

• ??,??????????????
• ????????????????,????
• ???????????????????

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???? Elementary particles
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????????

• ????
• (Quark matter)

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??????? Ultra-relativistic heavy-ion collisions

• QCD???????????????
• ??????????????? ??(phase transition)
• ???????

kTc 140 MeV
Tc1012 K!
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???? Quark Matter
?????
????????
Figures courtesy Brookhaven National
Lab http//www.bnl.gov/RHIC/
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????????? Relativistic Heavy Ion
Collider (1)
??? 2000???
???(??)??? 200 GeV/n (v 0.99995c)
??,???????1012 K,?????????
Brookhaven National Lab, NY
Figures courtesy Brookhaven National Lab
http//www.bnl.gov/RHIC/
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????????? Relativistic Heavy Ion
Collider (2)
Photo downloaded from http//www.bnl.gov/rhic/fas
cinating.htm
??????
?????????? STAR
Photo downloaded from http//www.star.bnl.gov/
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????? Au Au
Downloaded from Brookhaven National Lab
webpage http//www.bnl.gov/rhic/fascinating.htm
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?????

?????
Downloaded from Brookhaven National Lab
webpage http//www.bnl.gov/rhic/full_en_images.htm

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??????

• ???????????? ?????? (Quark-gluon
  Plasma)?
• ?????????,???????? 10-23 s
• ????????TltTc?????(?, K, p, n,)
• ?????????????
• ????

http//www.bnl.gov/bnlweb/pubaf/pr/2003/bnlpr06110
3.htm
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????????

• 2. ???
• (strange stars)

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??? (Compact Stars)

• ?????(M gt 3Mo)??????????(supernova)
• ???????????,????????? (1.5Mo, R10-100 km)

??? ???????????????????
?????
Animation courtesy Bryan Preston (STScI/AVL)
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??? Neutron Stars
50 km
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??? (Strange Stars)
??? u, d, s ??????? ?????????????????
???,????????? (R 7 km)
??? ????
4/2002 3C58 ?RXJ 1856.5-3754 ??????!
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RXJ 1856.5-3754
Photos courtesy NASA/CXC/SAO downloaded from
http//chandra.harvard.edu/press/kits/strangematte
r/index.html
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3C58
SN1181 ?????? ???? lt 106 K
Chandra X-ray
31
??????????

• ?????????????
• ??????? (Klaus Colanero, PhD)
• ?????? (??? MPhil)
• ????????????(??? MPhil)
• ?????????????? (??????,FYP)

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II. ???????

• ??? ????
• ??? ????

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?????

• ???????
• ??????
• deep inelastic scattering

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?????

• 1911
• ?? ? ??
• MeV
• ?????????
• 10-10 m ? 10-13 m

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?????? (1)

• 1960s
• ??????? 18 GeV
• ????/????????

Photos Courtesy Stanford Linear Accelerator
Center.
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?????? (2)
e
p
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?????? (3)

• ? ??????
• ? ??
• ??? (scaling)
• ?????? ??
• Feynman ??? (parton)

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?????? (4)
39
?????????

• ??? (parton)
• ????
• ?????? (????)?

partons
quarks
Richard Feynmann
Murray Gell-Mann
40
??????????

• ????????? (field theory)
• ????
• Gross, Politzer, Wilczek ??
• ?????? (Yang-Mills)
• ??????

41
???
42
????

• ?????????
• ???? (????) ?????,????
• ???? (????) ?????,?????
• ????????????,???????????

43
????

• ?
• ?

44
???

• ??
• ??
• ???
• ????

45
????

• ????

46
????
Running of the strong coupling constant
measurement at different scales compared to QCD
predication for??s0.1180.003. The last three
points correspond to the new LEP 2 measurements.
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???? ?s ??? (1)

• ??? renormalization group
• Gell-Mann Low
• Callan Symanzik

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???? ?s ??? (2)

• ??

?
?
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????

• ?????????
• tHooft (1971)
• ????????????,??????????

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??? Yang-Mills field

• EM
• YM

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??? Yang-Mills field
?????? Quantum ChromoDynamics
52
????
H. David Politzer
David J. Gross
Frank Wilczek
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?? ? ???

• ??? G(p) ??
• ? ??
• ??????

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?????

• ?
• ????,????
• 
  
• ? ???,?????
• ????????
• (non-perturbative)

59
?????

• ???????? lattice QCD
• ?????

t
x
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?????

• ?????
• ??

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????

• ?
• ?

????
2004????
????
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????????

• ?
• ??????????
• ????????

63
???????

• ?r?? ?????
• ????3x6???
• ????3???
• ??????????
• ????(?????)??-
• ???????-
• ???????????
• ??(????????)????
• ???????????

64
????
x

• ??
• ??

x
x
y
y
4???Einstein ?? 6???Calabi-? ??
S. T. Yau
?-Mills ?
C.N. Yang
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???????

• ??????