equation of state study in uu collisions at csr, lanzhou
DESCRIPTION
Equation of State Study in UU collisions at CSR, Lanzhou. Z. G. Xiao Institute of Modern Physics, CAS, Lanzhou, China. Quark Matter 2006 Nov14-20 Shanghai, China. Collaborators: X. Dong 2 , F. Liu 3 , X.F. Luo 2 , K.J. Wu 3 , H. S. Xu 1 , N. Xu 4 1 Institute of Modern Physics - PowerPoint PPT PresentationTRANSCRIPT
Equation of State Study in UU collisions at CSR, Lanzhou
Quark Matter 2006
Nov14-20 Shanghai, China
Z. G. XiaoInstitute of Modern Physics, CAS, Lanzhou, China
Collaborators:X. Dong2, F. Liu3, X.F. Luo2, K.J. Wu3, H. S. Xu1, N. Xu4
1 Institute of Modern Physics2 University of Science and Technology of China3 Central China Normal University4 Lawrence Berkeley National Laboratory
Contents
1 Introduction: EOS interest 2 HIRFL-CSR* complex
2.1 Machine status2.2 Experiment: status & plan
3 UU collision simulations3.1 High density in UU3.2 Event selection
4 Summary
HIRFL: Heavy Ion Research Facility at Lanzhou
CSR : Cool Storage Ring (500~1000MeV/u for HI )
EOS and its general interest EOS used as input, tested by exp./model. consistency.
Nucl. EOS
Initial conditions
Star fate, …
M-R
Max. M.Const.
… …
Evolution dynamicsCompact Star:
Initial conditions
Freeze
Out
Flow
K, …
Cluster
GMR …
Transport Process
H I C:
EOS representation
T. Klaehn et al., Phys. Rev. C 74, 035802 (2006)
00sym
20sym
20 )()()()(),( EEEEE
...
3...
1621823
22 L
JaV
Esym
Key Issues for EoS Program
1 Identify the bulk-matter with partonic degrees of freedom
2 Study the properties of the partonic matter
3 Demonstrate the transition between partonic and hadronic worlds
4 Understand multi-facets of HIC relevant to EOS study
CSR
1 Introduction: EOS interest 2 HIRFL-CSR* complex
2.1 Machine status2.2 Experiment: status & plan
3 UU collision simulations3.1 High density in UU3.2 Event selection
4 Summary
HIRFL-CSRcomplex
ECR Ion Source SFC k=70 (few AMeV) SSC k=450(~100 AMeV) CSRm Cooler synch.
~12.6Tm
~2.8GeV proton CSRe Acc./Deccel.
~9.6Tm RIBLL2 R~1200
ITE
ETE
J. W. Xia et al., NIM A 488, (2002) 11
Commission: 2006~2007
CSR Performance
CSRm CSRe
Ion species proton, C-U p, C-U,RIB,HCI
Beam Energy
(MeV/u)
Bmax=1.6T
2.8GeV p
1.1GeV/u 12C6+
0.52GeV/u 238U72+
2.3GeV p
~1 GeV/u 12C6+
~ 0.5 GeV/u 238U72+
P/P <10 - 4 <10 - 5
P/P 0.15% 0.5%
Emittance 5 mm mrad 1 mm mrad
7→1000MeV/u (C6+) Ramping Test 06/10/15 22:45
H = 2→1, frf = 0.45→1.63MHz, G = 11.3Tm
Particles: 2x108
External Target Facility (I)
Neutron + LCP + First experiment shifted to 2007
Conceptual Layout of ETF (II)
• 4 times larger acceptance of Dipole + Tracking inside;
• Gamma ball made of CSI;
• TOF (mRPC) covers forward region (30o).
Five years of construction after approved
NW: Prototype test/simulation results
Simulation
Real Test
Scintillator : <80
Calorimeter: <100
1 Introduction: EOS interest 2 HIRFL-CSR* complex
2.1 Machine status2.2 Experiment: status & plan
3 UU collision simulations3.1 High density in UU3.2 Event selection
4 Summary
Advantageous UU collisions
δ=0.23, A=238
Deformation larger volume along z axis
Good for collision dynamics studies
? Experimental observation
? Event selection
Tip-TipBody-Body
Density achieved in UU UU > AuAu at both energies 20AGeV: Tip-tip > Body-Body
520AMeV: Tip-tip ~ Body-Body
High energy
Low energy
B. A. Li et al., PRC61(2000), 021903
Idea of the event selections
At b=0
Tip-TipBody-Body
v2 = 0 v2 ≠ 0- high density!- longer duration!- easier reach thermalization!
Event selection in UU
Body-Body collisions exhibit large anisotropy in azimuth.
Event selection in UU
Event selection:
1) neutron multiplicity cut suppress body-body events
2) Larger ratio of tip-tip collisions survives a additional v2 cut.
3) Random geometrical configuration to be simulated.
5 Summary
EOS studies are drawing much attention and calling for more systematic studies.
HIRFL-CSR at Lanzhou, China can hope to add opportunities for nuclear EOS study in the high net-baryon density region. An External Target Facility (ETF) is in the preparing stage and detector R&D has started.
UU collisions provide a unique opportunity for creating a system with extended energy density and duration. The advantage is maintained only by effective identification of the geometrical configuration. Correlation between v2 and forward neutron multiplicity might practically help in the relevant energy region.
BACKUP SLIDES START HERE
Phase Space at 400MeV/u symmetrical collisions
BUU calculations
QCD Phase Diagram
CSR
EOS from HIC
DF favors softer EOS, while EF favors harder one; K roughly constrained in (167, 380)
P. Danielewicz et al., Science, 298(2002), 1592
Puzzles found more in detailed investigatioPuzzles found more in detailed investigationnMore in A. Andronic et al., PRC67(2003), 034907; PLB612(2005), 173
C. Fuchs et al., Phys. Rev. Lett 86, 1974 (2001)
Complication arises (1): Finite size effect
Due to nuclear transparency, density and/or pressure achieved in HIC is not so high as the full stopped scenario predicts. reduce the sensitivity on EOS ? virtually “soften” EOS ?
W. Reisdorf et al., PRL92(2004), 232301
CSR range
Esym and its density dependence
Probes: Mesons: pion ratio, Kaon rat
io n/p differential flow, ratio n/p ratio of fast nucleons Isospin diffusion IMF isospin HBT correlation function ……
00symsym )()( EE
CSR range
Esym: Isospin diffusion 124Sn+112Sn
Ein= 50MeV/u
69.0
0sym 6.31)(
E
B. A. Li et al., PRC 72, 064611 (2005)
L. W. Chen et al., PRL 94, 032701(2005)
M. B. Tsang et al., PRL92, 062701(2005)
Esym: n/p flow n/p flow predicted different, while experimentall
y NOT observed!
BUU model
Aladin+FOPI
Why ???
B. A. Li, PRL88 (2001), 192701
Y. Leifels et al., PRL71(1993),963
Au+Au 400MeV/u
Neutron Wall
Active area 1.5×1.5m2
Thickness 1m
Acceptance ±3.80
coverage 11~20 mSr
Angular resolution 0.30
Efficiency ( 1 GeV n ) >90%
Position resolution ±8cm
E resolution ( < 1 GeV n )
5 %
Main parameters
Big Dipole ready
Main parameters
B Field 1.6 Tesla
Gap height 270 mm
Gap Width 1000 mm
Thickness 980 mm
Distance to target 1 m
MWDC before and after dipole