The

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The Little Bang in the Laboratory
Accelorator Physics.
Christina Markert

• Big Bang
• Quarks and Strong Interaction
• Heavy Ion Collisions Little Bang
• Our Heavy Ion Group at UT Austin
• Conclusions

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Our basic Questions are

• What is matter made of ?
• How does matter organize itself
• stay together?
• How does matter behave?

3
Space Time Diagram of the Early Universe
crystal
molecule
atom
nuclei
proton
Expansion Temperature decrease Density
decreases Volume expands It takes time More
structure
quarks
Universe is 13109 Years old
The Cosmic Timeline
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What do we know about the smallest building
blocks?
5
Quarks in a Neutron or Proton Mass
Theory Quantum Chromo Dynamics
Quarks are the smallest building blocks of
massive matter
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Analogies and differences between QED and QCD
to study structure of an atom
electron
separate constituents
nucleus
QED Quantum Electro Dynamics
neutral atom
Confinement fundamental crucial (but not
understood!) feature of strong force - colored
objects (quarks) have ? energy in normal vacuum
quarks u,d, (s,c,t,b)
quark
Strong color field Force grows with separation !!!
white ?0 (meson) (confined quarks)
white proton (baryon) (confined quarks)
white proton
QCD Quantum Chromo Dymanics
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Generating a deconfined state

• Present understanding of Quantum Chromodynamics
  (QCD)
• heating
• compression
• ? deconfined matter !

Nuclear Matter (confined)
Hadronic Matter (confined)
Quark Gluon Plasma deconfined !
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Going back in time
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Phase Transitions
ICE
WATER
Add heat
Quark Gluon Plasma is another phase of matter!
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Phase Diagram
Pressure
We heat up the system
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Create Quark Gluon Plasma
Hadrons
Quark Gluon Plasma
Compress andAdd heat
T 1,000,000,000,000 K
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Phase Diagram of Nuclear Matter
hadrons quarks and gluons hadrons
Pressure
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Phase transition of nuclear matter predicted
Gross, Politzer, Wilczek win 2004 Nobel Prize in
physics for the theory of asymptotic freedom in
strong interaction. The Relativistic Heavy Ion
Collider (RHIC) at Brookhaven National
Laboratory (BNL) was built to measure the phase
transition of nuclear matter to an
asymptotically free partonic state (deconfined)
under the condition of maximum particle and
energy density. (after Big Bang ?)
Wilczek
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What can we do in the laboratory ?

• a.) Re-create the conditions as close as
  possible to the Big Bang, i.e. a condition of
  maximum density and minimum volume in an
  expanding macroscopic system.
• b.) Measure a phase transition, characterize the
  new phase, measure the de-excitation of the new
  phase into ordinary matter do we come out
  the way we went in ?
• c.) Learn about hadronization ? how matter is
  formed
• (mechanism how quarks from hadrons
• protons, neutrons, etc)

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How do we do heavy ion collisions in laboratory ?

• We take an atom (Au)
• We take away the electrons ? ion
• We accelerate the ion
• We collide the ions and hopefully create the
  predicted quark gluon plasma in our
• little bang (AuAu)

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Relativistic Heavy Ion Collider (RHIC)
1 mile
v 0.99995?c
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STAR experiment at RHIC collider
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Study all phases of a heavy ion collision
If the Quark Gluon Plasma was formed, it will
only live for 10-23 s !!!! Nuclei are so thin
because of velocity nearly speed of light
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Space Time Diagram of the Early Universe
crystal
molecule
atom
nuclei
proton
Expansion Temperature decrease Density
decreases Volume expands More structure
quarks
Takes time
atoms 6105years
The Cosmic Timeline
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Heat and Compress Nuclear Matter

• We produce new quark-antiquark pairs
• Producing new matter out of Energy
• Producing new quarks s,c,t,b which dont exist
• in ground state nuclear matter
  (neutronsprotons)
• System expands? new particles are produced
• Protons (uud) , anti-protons (antimatter)
• Lambdas (uds)

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STAR Experiment at the RHIC Collider
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Particle Tracks in the Detector
Head-on AuAu collision
1500 charged hadrons (protons,) and leptons
(electrons,..)
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What can we measure ?

• a.) Which particles are produced ?
• b.) How many are produced ?
• c.) How are they arranged (angle)
• d.) What does the theory tell us?

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Resonance Reconstruction in STAR TPC
Energy loss in TPC dE/dx
End view STAR TPC
?
p
?-

• Identify decay candidates
• (p, dedx, E)
• Calculate invariant mass

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Time of Flight Detector
                                                
                                         
Our Group at UT Austin
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Conclusion

• Data show evidence that we created a Quark Gluon
  Plasma
• We have a phase transition proton -gt quarks
• Quark-gluon plasma lasts less than
  0.00000000000000000000001 seconds
• It is very dense and very hot
• It behaves like a liquid not like a plasma
• New experiment at larger Collider LHC at CERN to
  investigate properties of the Quark Soup

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The world takes notice !
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Questions
1.Can we produce anti matter here on earth ?
Yes 2.Can we create matter out of energy ?
Yes 3.Is the proton the smallest building block
of nuclear matter ? No (quark) 4.Can we
accelerate particles up to nearly the speed of
light ? Yes 5.Can we observe a single quark ? No