Transcript Heavy Ions for Science and Society

Heavy Ions for Science and Society
Dieter Roehrich
UiB, Norway
• 50 Years of Heavy Ion Physics
• Heavy Ions for Science
• What is matter?
• Heavy Ions for Society
• Health
• Archaeology
• Materials
Why do we need particle accelerators?
To accelerate particles to high energies!
The higher energies allow us
i)
to look deeper into matter
(E  1/size), (“powerful microscopes”)
de Broglie
ii) to discover new, heavier particles
(E = mc2)
iii) to probe matter at extreme conditions;
to probe conditions of the early universe
(E = kT)
Einstein
Boltzmann
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What is matter?
Constituents of the universe
visible universe
M.S. Turner, Sci. Am., Sep. 2009
”QCD-matter”
made up of quarks and gluons - macroscopic manifestion of the strong interaction
nuclear matter
@ nuclei
QCD = Quantum ChromoDynamics
neutron/
quark matter
@ neutron stars?
q q q q
q
q qq
q q q q q
q
q q q q
q
q q qq
q quark-gluon
q qq q q q
matter
q qq q q
q
q
q
@ LHC
q q
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Questions
• Confinement
• Quarks and gluons are confined in bags of radius r0
• All hadrons (baryons and mesons) have the same radius
• Characteristic length scale: r0 = 1 fm
• Characteristic energy scale: hc/ r0= 200 MeV
• Generation of mass
• mUP  mdown  few MeV/c2
• Nucleon mass  940 MeV/c2
• Dynamic generation of mass!
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More questions
• History of the universe
• first 10 sec:
energy density
 1 GeV/fm3
temperature
 160 MeV
• hot soup of quarks,
leptons and force
carriers,…
• properties of new
states of matter at
high temperatures
and densities
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Rephrasing it ...
Habe nun, ach! Philosophie, Juristerei und Medizin,
Und leider auch Theologie
Durchaus studiert, mit heißem Bemühn.
Da steh ich nun, ich armer Tor!
Und bin so klug als wie zuvor;
[...]
Drum hab ich mich der Magie ergeben,
[...]
Daß ich erkenne, was die Welt
Im Innersten zusammenhält, ...
Goethe, Faust I, Vers 382 f.
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Heavy Ion Physics
Collision of heavy nuclei with
kinetic energies above the
Coloumb barrier
• High energy
• Quark-gluon plasma
• Degrees of freedom:
quarks and gluons
• Strong interaction
• Low energy
• Nuclear matter
• Degrees of freedom:
hadronic bound states
• Nuclear interaction
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History of heavy ion accelerators
• The early years (60’s) –
light ions (Li, C, O, Ne), a few MeV/nucleon
• Electrostatic accelerators: Van de Graaff, Tandem
The Bergen van de Graaff accelerator
– built in 1953, still running
The MPI Heidelberg Tandem
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History of heavy ion accelerators
• Cyclotrons and linear accelerators (since 70’s & 80’s)
– heavy ions, a few
10 MeV/nucleon
• UNILAC at GSI (since 1975)
• GANIL (Caen)
• …
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History of heavy ion accelerators
• Synchrotrons
• Relativistic heavy ion collisions (a few GeV/nucleon)
• Bevalac/LBL – 1974-1993
• AGS/BNL – 1986-1995
• SIS/GSI – since 1990
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Bevalac
SuperHILAC
Bevatron
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AGS
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History of heavy ion accelerators
• Synchrotrons
• Ultra-relativistic heavy ion collisions (a few hundred GeV/nucleon)
• Fixed target: SPS/CERN – since 1986
• Collider: RHIC/BNL – since 2000
• Ultra-relativistic heavy ion collisions (a few TeV/nucleon)
• Collider: LHC/CERN – since 2009
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RHIC
Relativistic
Heavy Ion Collider --- RHIC
• Au
+ Au collisions
- 100 GeV/nucleon + 100 GeV/nucleon
STAR
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Large Hadron Collider @ CERN
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LHC – accelerator complex
The counter rotating proton
and heavy ion beams are
brought into collision at four
experimental collision points
around the LHC:
At
CMS
LHCb
ATLAS
ALICE
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LHC–project: accelerator + experiments
• LHC circumference: 27 km
• about 100 m underground
• Protons and
heavy ions
circulate at
99.999999%
of the speed
of light
• Four large
caverns for
experiments
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LHC - components
• 1232 superconducting
dipole magnets bend
the beams
• Radiofrequency cavities
accelerate the ion
bunches
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Size: 16 x 26 meters
Weight: 10,000 tons
TOF TRD
HMPID
ITS
PMD
Muon Arm
PHOS
ALICE Set-up
TPC
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The physics
• Nuclear matter at extreme conditions
• Extreme shapes
• Superheavy elements
• Radioactive nuclei far away from stability
• Phase diagram of strongly interacting matter
• Liquid-gas phase transition
• Dense baryonic matter – neutron stars
• Quark Gluon Plasma – Little Big Bang
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Nuclear structure and dynamics
• Extreme shapes of nuclei
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Superheavy elements
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Radioactive nuclei far away from stability
• Nuclei relevant for astrophysical processes
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The QCD phase diagram
• Goal: exploring phases and structures of the QCD phase diagram
hot & dense
• Tool: (Ultra-)relativistic heavy ion collisions
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Liquid-gas phase transition
• Peripheral collisions of heavy nuclei at low energies
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Astrophysics – Neutron Star
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Heavy Ion Collisions at the LHC
On Sunday November 7th, 2010, the ALICE
experiment recorded the very first Pb-Pb collision
• Collision of two lead nuclei
at 5.5 TeV per nucleon pair
= 1100 TeV
• macroscopic energy
1100 TeV = 0.2 mJ
 collision of two mosquitos
BUT
energy is squeezed into a
microscopic volume
fireball – a billion times hotter than the sun
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Little Bangs vs Big Bang
• Many small events
• Strong initial
fluctuations
• One large event
• very homogenous
• Asymmetric event shape
Evolution of the fluctuating initial condition reveals matter properties
Measuring the energy loss of a parton
traversing the QGP
Photon
(191GeV)
Jet
(98 GeV)
• fast quarks and gluons
loose energy in the
medium
-> Quark-Gluon Plasma
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Heavy Ions for Society
• Health: 12C cancer therapy
• Accelerator Mass Spectroscopy
(AMS): 14C dating
Bevalac
treatment
beamline
• Material structuring: nanostructures
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The end
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