Transcript GSI and more energies

“Polarization studies as additional tool to search
and study of the quark-gluon plasma”
S.S. Shimanskiy (VBLHE, JINR)
QGP’2000 at CERN
A common assessment of the collected data leads
us to conclude that we now have compelling
evidence that a new state of matter has indeed
been created, at energy densities which had never
been reached over appreciable volumes in
laboratory experiments before and which exceed
by more than a factor 20 that of normal nuclear
matter. The new state of matter found in heavy
ion collisions at the SPS features many of the
characteristics of the theoretically predicted
quark-gluon plasma.
QGP’2003 at BNL
•
TJH RHIC PAC 9/29-30, 2003 TJH RHIC PAC 9/29-30, 2003
Conclusions About Matter at RHIC:
– The data on high pt suppression and correlations support the
conclusion that we have produced a medium that:
•
•
- is dense; (pQCD theory →many times cold nuclear matter density)
- is dissipative( very strongly interacting)
– We need to show that:
•
•
•
- dissipation and collective behavior occur at the partonic stage
- the system is deconfined and thermalized
- a transition occurs: can we turn the effects off ?
– We need:
• - extended AuAu run needed to address several important probes
that need large data sets ( e.g., pT-dependence of suppression; J/ψ, ϒ,
open charm, heavy baryon / meson flow); also, species and energy
scans to map the evolution of key observables
• - more guidance from theory (!) particularly on what to expect from
hadronic scenarios
QGP + SPIN
How we can use SPIN to find
thermalization?
the system
is
thermalized

in the plasma rest
frame there is no
preferred direction,
no polarization
Paul Hoyer, Physics Letters B,v.187 (1987)162
Particle polarization as a signal of plasma formation
“Heavy ion collisions leading to the
formation of quark-gluon plasma are
characterized by an isotropic distribution of
the parton momenta in the plasma rest
frame. We discuss the restrictions that this
isotropy imposees on the polarizations of
plasma-produced virtual photons,
hyperons and hadronic resonances. “
Dileptons as an unique probes for QGP
•
Haven’t strong interaction.
• Come out from all evolution
stages.
CERES/NA45 data
Dileptons Anisotropies. How we can
resolve sub processes using its?
NN-reactions
TRANSPARENCES
e+e- anisotropy (theory)
E.L. Bratkovskaya, O.V. Teryaev, V.D. Toneev from JINR
Phys. Lett. B 348 (1995) 283.
E.L. Bratkovskaya, O.V. Teryaev, V.D. Toneev +
W. Cassing, U. Mosel, M. Schafer from Giessen
Phys. Lett. B 348 (1995) 325.
W. Cassing, E.L. Bratkovskaya
Physics Reports 308 (1999) 65-233.
GSI and more energies
Bratkovskaya E.L. et al., Z. Phys. C 75, 119.126 (1997)
SPS energy
Bratkovskaya E.L. et al., Z. Phys. C 75, 119.126 (1997)
SPS energy II
Rapp R., hep-ph/0201101
The STAR Barrel TOF
MRPC Prototype
Prototype Tray
Construction
at Rice University
MRPC design developed at
CERN, built in China
28 MRPC
Detectors;
24 made at
USTC
FEE
Neighbor
CTB Tray
  70 ps, 2 meter path
Strong team including 6
Chinese Institutions in place
EMC
Rails
Completed Prototype 28 module MRPC
TOF Tray installed in STAR Oct. ‘ 02 in
place of existing central trigger barrel tray
Examples of Benefit of TOF
Open Charm and Resonances in central Au-Au collisions
pT
(GeV/c)
FOM
Do
All
4.6
Do
2-4
2.6
Do
4-6
2.0
Do
>6
1.0
K*o
0-1
2.0
K*o
1-2
1.85
K*o
2-3
1.74
K*o
3-5
1.39
f (1020)
0-2
5.0
f (1020)
2-5
L (1520)
0-1.6
3.4
11.4
FOM (figure of merit) = reduction
in required data set by using TOF
PID
TOF PID also reduces systematic
errors from correlated background due to misidentified
particles
Certain measurements are impossible
without TOF – unlike particle
correlations (X-p), scale dependent
correlation studies (velocity vs
momentum correlations), exotic
searches…
TOF + TPC electron Tag
• Works well at low energy –
complements calorimeter
• Gives access to vector meson
(,,f,J/) e+e- decays
• Thermal dileptons
• Single electron spectrum
• D meson yield, flow
RHIC energy
Rapp R., hep-ph/0201101
J/ polarization
Ioffe B.L., hep-ph/0310343
Dubna, SPIN 2003
What will be interesting for
investigations ?
(Will need to compare pp and
AA data, energy and impact
parameter dependences)
Thank you!