1. Bulk  Eigenschaften von QCD  Materie bei höchsten Kolliderenergien
Kai Schweda, Universität Heidelberg / GSI Darmstadt

2. Building Blocks of Matter
Quantum Chromodynamics (QCD) is the established theory of strongly interacting matter.
Gluons hold quarks together to from hadrons:
Gluons and quarks, or partons, typically exist in a color singlet state: confinement.
meson
baryon

3. Quark Gluon Plasma Quark Gluon Plasma: Deconfined and
Source: Michael Turner, National Geographic (1996)
Quark Gluon Plasma:
Deconfined and
thermalized state of quarks and gluons
 Study partonic Equation of State: relation between p, , T

4. Colliding Heavy Nuclei

5. Outline
Identify and study QCD bulk-matter with partonic degrees of freedom:
Collectivity at RHIC
ALICE at LHC at the energy frontier
CBM at FAIR at the baryon density frontier
Summary

6. High-Energy Nuclear Collisions
Time 
1) Initial condition: 2) System evolves: 3) Bulk freeze-out
Baryon transfer - parton/hadron expansion - hadronic dof
- ET production - inel. interactions cease:
Partonic dof particle ratios, Tch, mB
- elas. interactions cease
Particle spectra, Tth, <bT>
The only possibility to create such a state is by colliding heavy nuclei at the highest energies.
You see here a schematic view of a nuclear collisions. Both nuclei are lorentz contracted along the beam direction. They overlap and deposit energy in the collision region. The systems then evolves, it expands and therefore cools down. Hadrons are formed. The system gets more and more dilute. When inelastic interaction cease, hadron yields are fixed, this is commonly referred as chemical freeze out.
Finally, elastic interaction cease and particle spectra are fixed, kinetic freeze-out.
Plot: Steffen A. Bass, Duke University

7. Au + Au Collisions at RHIC
Peripheral Event
STAR
(real-time Level 3)

8. Au + Au Collisions at RHIC
Mid-Central Event
STAR
(real-time Level 3)

9. Au + Au Collisions at RHIC
Central Event
STAR
(real-time Level 3)

10. Hadron Yield - Ratios 1) At RHIC: Tch = 160 ± 10 MeV B = 25 ± 5 MeV
 The hadronic system is thermalized at RHIC.
3) Short-lived resonances show deviations.
 There is life after chemical freeze-out.
RHIC white papers , Nucl. Phys. A757, STAR: p102; PHENIX: p184;
Statistical Model calculations: P. Braun-Munzinger et al. nucl-th/

11. Chemical Freeze-Out vs Energy
With increasing energy:
Tch increases and saturates at Tch = 160 MeV
Coincides with Hagedorn temperature
Coincides with early lattice results  limiting temperature for hadrons, Tch  160 MeV !
mB decreases, mB  1MeV at LHC
 Nearly net-baryon free !
A. Andronic et al., NPA 772 (2006) 167.

12. QCD Phase Diagram

13. Pressure, Flow, … Thermodynamic identity – entropy p – pressure
U – energy V – volume
t = kBT, thermal energy per dof
In A+A collisions, interactions among constituents and density distribution lead to:
pressure gradient  collective flow
number of degrees of freedom (dof)
Equation of State (EOS)
cumulative – partonic + hadronic

14. (Anti-)Protons From RHIC
More central collisions
In central collisions, spectra become more convex  stronger collective flow !

15. Kinetic Freeze-out at RHIC
1) Multi-strange hadrons  and  freeze-out earlier than (p, K, p)
 Collectivity prior to hadronization
2) Sudden single freeze-out*:
Resonance decays lower Tfo
for (p, K, p)
 Partonic Collectivity
STAR Preliminary
STAR Data: Nucl. Phys. A757, ( ),
*A. Baran, W. Broniowski and W. Florkowski, Acta. Phys. Polon. B 35 (2004) 779.

16. Anisotropy Parameter v2
coordinate-space-anisotropy  momentum-space-anisotropy y py x px
Initial/final conditions, EoS, degrees of freedom

17. v2 in the Low-pT Region
P. Huovinen, private communication, 2004
Minimum bias data! At low pT, model result fits mass hierarchy well!
- Details do not work, need more flow in the model!

18. v2 of Multi-Strange Hadrons  and 
Strange-quark flow - partonic collectivity at RHIC! NB:  K+ + K- (BR 49%)  e+ + e- (BR 0.03%)
QM05 conference: M. Oldenburg; nucl-ex/

19. Collectivity - Energy Dependence
Collectivity parameters <bT> and <v2> increase with energy
Two extreme scenarios: (a) Tfo  Tch AND br  0.8  pure partonic collectivity at LHC! (b) Tfo  Tch , br  0.3  no collectivity, no QGP !
K.S., ISMD07, arXiv: ﾊ[nucl-ex].

20. Partonic Collectivity at RHIC
1) Copiously produced hadrons freeze-out p,K,p:
Tfo = 100 MeV, T = 0.6 (c) > T(SPS)
2) Multi-strange hadrons freeze-out :
Tfo = MeV (~ Tch), T = 0.4 (c)
3) Multi-strange v2:
Multi-strange hadrons f,  and  do flow!
4) Constituent Quark scaling:
Seems to work for v2 and RAA (RCP)
Deconfinement &
Partonic (u,d,s) Collectivity !

21. Particle Multiplicities
PHOBOS fit
HIJING BBar
Armesto et al.
AMPT
Eskola
CGC
KLN
ASW
DPMJET-III
EHNRR
at LHC, dN/dh 
estimate energy density
PHOBOS compilation: W. Busza, SQM07.
Theory points: HI at LHC – last call for predictions, CERN, May 2007.

22. EoS from Lattice QCD 1) Large increase in  ! Large increase in Ndof:
Hadrons vs. partons
2) TC ~ 160 MeV
3) Boxes indicate max. initial temperatures
Longest expansion duration at LHC
Expect large partonic collectivity at LHC
SPS
RHIC
LHC ?
Z. Fodor et al, JHEP 0203:014(02)
C.R. Allton et al, hep-lat/
F. Karsch, Nucl. Phys. A698, 199c(02).

23. Heavy  Quark Production
Heavy-quark production at LHC, compared to RHIC expect factors
Charm  10
Beauty  100
(i) Heavy-quarks abundantly produced at LHC energies !
(ii) Large theoretical uncertainties  energy scan (LHC,FAIR) will help !
Plots: R. Vogt,Eur. Phys. J. C, s x (2008).

24. Quark Masses Strong interactions do not affect heavy-quark masses.
Higgs mass: electro-weak symmetry breaking (current quark mass).
QCD mass: Chiral symmetry breaking (constituent quark mass).
Strong interactions do not affect heavy-quark masses.
New scale: mc >> QCD.
Calibrated probe:
- test pQCD, initial cond. - drag/diffusion - chiral symmetry rest.
X. Zhu, M. Bleicher, K.S., H. Stoecker, N. Xu et al., PLB 647 (2007) 366.

25. Debye Screening

26. J/y Production  suppression, compared to scaled p+p
P. Braun-Munzinger and J. Stachel, Nature 448 (2007) 302.
 suppression, compared to scaled p+p
 regeneration, enhancement
(SPS)
Low energy (SPS): few ccbar quarks in the system  suppression of J/y
High energy (LHC): many ccbar pairs in the system  enhancement of J/y
 Signal of de-confinement + thermalization of light quarks !

27. Predictions for LHC scc large charm production at LHC
strong regeneration of J/y
striking centrality dependence
Signature for QGP formation !
Initial conditions at LHC ?
Need to measure total charm production in PbPb !
Also: check ’ ratio vs stat. model predictions
scc
A. Andronic et al., Phys. Lett. B 652 (2007) 259.

28. D  Dbar Correlations vs 
PYTHIA: p + 14 TeV
c-cbar Mesons are correlated
Pair creation: back to back
Gluon splitting: forward
Flavor excitation: flat
Exhibit strong correlations !
Baseline at zero: clear measure of correlations !
 probe thermalization among partons !
G. Tsiledakis and K.S., [nucl-ex], [nucl-ex].

29. Where does all the charm go?
J c
D*± Ds D0 D
Measure open-charm mesons, e.g. D0 and D* to address: (a) total charm production (b) heavy-quark collectivity
Statistics plot: H. Yang and Y. Wang.

30. Hadronen mit schweren Quarks (charm und beauty)
Viele neue interessante Signale in ALICE bei LHC: z.B.
Hadronen mit schweren Quarks (charm und beauty)
D0, D+, D*, Ds, J/y, y’, Lc, Lb, 

31. Large Hadron Collider LHC at CERN p + p @ 7 + 7 TeV
Pb TeV
LHC TeV c km/h
Tevatron TeV c km/h
RHIC GeV c km/h
Geiger and Marsden MeV c * 5%

32. ALICE at LHC 1000 scientists, 30 nations
TRD
ITS
TPC
ITS: measures secondary vertex, open heavy-flavor, c and b
TPC: tracks and identifies charged particles, (e,), , K, p
TRD: identifies electrons above 1 GeV, fast trigger (6s)

33. D0  p+ + K- Reconstruction
D0, ct = 123 mm
Plot: A. Shabetai

34. D0 - Meson Performance
Measure secondary vertex  Direct reconstruction of D0  precise measurement of total heavy-quark yield  address heavy – quark collectivity !
ALICE: PPR.vol.II, J. Phys. G 32 (2006) 1295.

35. D* meson Identification
D*+  D0 + +
Identify D*+ through M[D*+ - D0]
Subtract resonance decay to D0
Two different methods to address total charm production
D*± analysis: Yifei Wang, Ph.D. thesis, University of Heidelberg, in preparation.

36. J/y  e+ + e- Reconstruction
J/y: c c
: b b
J/y  e+ + e-
identify electrons through their transition radiation
 Precise Measurement of Quarkonia !
Wolfgang Sommer, Ph.D. thesis, Frankfurt University.

38. ALICE in 2004

39. ALICE: Getting ready…

40. ALICE - Ready for Physics !

41. Summary LHC
Bulk properties at LHC: dN / dh  1000 – 3000 Tch  160 ± 10 MeV, mB  0 – 5 MeV Tfo  Tch  all collectivity from partonic stage <bT> = 0.8 ± 0.05 (c), <v2>  0.08
Measure spectra, correlations and v2 of: D0, D+, D*, Ds, J/y, y’, Lc, Lb,  to identify and characterize QGP !
ALICE is well suited for these studies

42. Energy Dependence
Look for statistical hadronization of charm at top FAIR energies
c most sensitive !
Need total charm cross section as reference: measure D-mesons !
 Need -vertex detector

43. Chiral Partners ? cu-system D-mesons: heavy-light system
hydrogen atom of QCD
(0+)
(1+)
Belle
(2003)
~Mq
D(2308)
D(2427)
Chiral mass shifts  420 MeV
(constituent quark mass)
D(0+)  D(0-) +  c u 1- 0-
D*(2010)
~1/mQ
Light-quark-cloud
probes chiral symmetry
D(1869)
Look for effects of chiral symmetry restoration at CBM/FAIR using heavy-quarks !

44. Kurtosis Analysis for Net  Baryons
Quark Number Susceptibility
On Lattice: a spike in susceptibility means long range correlation at the critical point.
The equilibration of the medium is assumed in all Lattice calculations.
In Experiment: measure the correlation function of net-baryons or p, .
Need -vertex detector !
Light quarks
Strange quarks

45. Nuclear phase diagram Heavy quarks with ALICE at LHC:
- Study medium properties
- pQCD in hot and dense environment
FAIR/GSI program:
- Search for the possible phase boundary.
- Chiral symmetry restoration
Energy scan