Relativistic Heavy Ion Collider and Ultra-Dense Matter. Physics Goal: Extended Volumes of Hadronic Matter with Energy Densities Greater Than 10 Times of Atomic Nuclei. Hadrons: Strongly interacting particles.
Relativistic Heavy Ion Collider
Physics Goal: Extended Volumes of Hadronic Matter with Energy Densities Greater Than 10 Times of Atomic Nuclei
Hadrons: Strongly interacting particles
Experiments agree: Matter has been made
exceeding this energy density which is strongly
interacting with itself, and to a good
Theorists call this matter the
Quark Gluon Plasma
What is the Quark Gluon Plasma?
The Color Glass Condensate?
Why is it important?
What is the evidence for these forms of matter?
The Quark Gluon Plasma:
Squeeze ordinary strongly interacting particles to a
density much larger than the density of matter inside
a typical strongly interacting particle. The quarks
and gluons should become unconfined.
When energy density jumps: mixed phase
Energy jumps do not set up pressure gradients
In the mixed phase
Confinement? Mass Generation?
Why is the Study of High Density Matter Important?
How is matter made from quarks and gluons?
What is the high energy limit of strong interactions?
How does confinement and mass arise?
How do phase transitions influence cosmology?
How do neutron stars and gamma ray bursters work?
What is the Color Glass Condensate?
Fast moving hadron with energy E
Many gluon constituents with energy e
X = e/E
Color: Gluons are carry color charge
Glass: Gluons at small x arise from fast moving gluons.
They evolve in time very slowly because their source’s
Time scale is Lorentz time dilated. Gluons are disordered.
Condensate: Gluon density is as high as it can be:
The phase space density
is as large as possible
Negative potential energy and repulsive interactions of order
Because density is high, separation of gluons is small,
interactions become weak:
Phase space density becomes large.
Matter is universal for all hadrons!
Gold-Gold Scattering at RHIC
100 Gev/A in each beam
~ thousands of particles per collision
Fast particles made last because
of Lorentz time dilation
Like Hubble expansion!
Enough energy density at RHIC to make new forms of matter!
Flow: Conversion of spatial gradients into momentum gradients
Flow is effective at early time before mixed phase
Requires very early time
T ~ .2-.3 Fm/c
Quark Gluon Plasma
Media can reduce number of jets seen
And can reduce back to back correlations
Requires very strong interactions!
Very high initial energy density!
Are particle distributed according to thermal distributions?
Measure temperature and density at late times.
A new range of parameter space to explore!
The Color Glass Condensate controls the
Good semi-quantitative and qualitative agreement
Color Glass Condensate Provides a Theory of
Modification of Gluonic Nuclear Wavefunction
Dramatic effects seen
In dA collisions!
Agrees with semi quantitative computation.
Small effect in the central region at RHIC
(particles with low longitudinal momentum in the center of mass frame)
RHIC has made new forms of matter.
For some of the lifetime of this matter it is to a good
approximation in thermal equilibrium
Theorists call this thermalized matter the Quark Gluon Plasma
At early times, strong hints of a Color Glass Condensate
Will characterize this matter in future experiments at RHIC
Experiments at higher energies and with electrons provide
potentially exciting ways to study this matter