Transcript The `Little Bang` in the Laboratory

The ‘Little Bang in the Laboratory’
– Accelorator Physics.
Christina Markert
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Big Bang
Quarks and Strong Interaction
Heavy Ion Collisions ‘Little Bang’
Our Heavy Ion Group at UT Austin
Conclusions
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Physics Workshop UT Austin November 11 2006
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Our basic Questions are:
What is matter made of ?
How does matter organize itself
& stay together?
How does matter behave?
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Physics Workshop UT Austin November 11 2006
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Space Time Diagram of the Early Universe
quarks
molecule crystal
nuclei atom
Expansion:
proton
Temperature decrease
Density decreases
Volume expands
It takes time
More structure
Universe is
13*109
Years old
The Cosmic Timeline
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Physics Workshop UT Austin November 11 2006
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What do we know about the smallest building
blocks?
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Physics Workshop UT Austin November 11 2006
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Quarks in a Neutron or Proton = Mass
Theory:
Quantum
Chromo
Dynamics
Quarks are the smallest building blocks of massive matter
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Physics Workshop UT Austin November 11 2006
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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
quark-antiquark pair
created from vacuum
quark
“white” proton (baryon)
(confined quarks)
Christina Markert
quarks
u,d, (s,c,t,b)
Strong color field
“white” 0 (meson)
“white”
proton
Force
grows
with separation(confined
!!!
quarks)
QCD Quantum Chromo Dymanics
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Generating a deconfined state
Present understanding of
Quantum Chromodynamics (QCD)
• heating
• compression
 deconfined matter !
Hadronic
Nuclear
Matter
Matter
Quark
Gluon
Plasma
(confined)!
deconfined
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Physics Workshop UT Austin November 11 2006
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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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Physics Workshop UT Austin November 11 2006
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Phase Diagram
Pressure
We heat up the system
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Physics Workshop UT Austin November 11 2006
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Create Quark Gluon Plasma
Quark Gluon
Plasma
Hadrons
q
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Compress
and
Add heat
Christina Markert
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T = 1,000,000,000,000 K
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Temperature
Phase Diagram of Nuclear Matter
LHC
RHIC
~150
MeV
q
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q q
q
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q q
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hadrons
q
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quarks and gluons
q
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hadrons
SPS
Center of mass energies:
for different accelerators
AGS: √s ~
5 GeV
SPS : √s ~ 17 GeV
RHIC: √s ~ 200 GeV
LHC: √s ~ 5500 GeV
AGS
Pressure
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Physics Workshop UT Austin November 11 2006
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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 ?)
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Physics Workshop UT Austin November 11 2006
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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Physics Workshop UT Austin November 11 2006
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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’ (Au+Au)
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Physics Workshop UT Austin November 11 2006
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Relativistic Heavy Ion Collider (RHIC)
PHOBOS
PHENIX
1 mile
Au+Au @ sRHIC
NN=200 GeV
BRAHMS
STAR
v = 0.99995c
AGS
TANDEMS
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Physics Workshop UT Austin November 11 2006
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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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Physics Workshop UT Austin November 11 2006
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Space Time Diagram of the Early Universe
quarks
molecule crystal
nuclei atom
Expansion:
proton
Temperature decrease
Density decreases
Volume expands
More structure
Takes time
atoms 6*105years
The Cosmic Timeline
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Physics Workshop UT Austin November 11 2006
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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 don’t exist
in ground state nuclear matter (neutrons+protons)
System expands new particles are produced:
Protons (uud) , anti-protons (antimatter)
Lambdas (uds)
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Physics Workshop UT Austin November 11 2006
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STAR Experiment at the RHIC Collider
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Physics Workshop UT Austin November 11 2006
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Particle Tracks in the Detector
Head-on Au+Au collision
~1500 charged hadrons (protons,…)
and leptons (electrons,..)
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Physics Workshop UT Austin November 11 2006
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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
K-
p
(1520)
Energy loss dE/dx
End view STAR TPC

p

e
momentum [GeV/c]
p
-
• Identify decay candidates
(p, dedx, E)
• Calculate invariant mass
minv 
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K
Physics Workshop UT Austin November 11 2006
E1  E2 2  p1  p 2 
2
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Time of Flight Detector
Our Group at UT Austin
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Physics Workshop UT Austin November 11 2006
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Conclusion
 Data show evidence that we created a Quark
Gluon Plasma
 We have a phase transition proton -> 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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Physics Workshop UT Austin November 11 2006
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The world takes notice !
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Physics Workshop UT Austin November 11 2006
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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
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Physics Workshop UT Austin November 11 2006
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