23
1 ISMD, Berkeley, Aug 4 9, 2007 Kai Schweda Bulk Properties of QCD – matter at Highest Colider Energies Kai Schweda, University of Heidelberg / GSI Darmstadt
1 ISMD, Berkeley, Aug 4 9, 2007 Kai Schweda
Bulk Properties of QCD – matter at Highest Colider Energies
Kai Schweda, University of Heidelberg / GSI Darmstadt
2 ISMD, Berkeley, Aug 4 9, 2007 Kai Schweda
QCD Phase Diagram
3 ISMD, Berkeley, Aug 4 9, 2007 Kai Schweda
Outline
Identify and study QCD bulk-matter with
partonic degrees of freedom:
• Gobal observable multiplicity
• Chemical freeze-out, Tch and B
• Partonic collectivity, Tfo and T
• Heavy – quark collectivity
• Summary
4 ISMD, Berkeley, Aug 4 9, 2007 Kai Schweda
Mid rapidity DensitiesPHOBOS fit
HIJING BBar
Armesto et al.
AMPT
Eskola
CGC
KLN
ASW
DPMJET-III
EHNRR
at LHC, dN/d 1000 3000
estimate energy density Theory points: HI at LHC – last call for predictions, CERN, May 2007.PHOBOS compilation: W. Busza, SQM07.
dy
dE
RT
Bj0
2
11
5 ISMD, Berkeley, Aug 4 9, 2007 Kai Schweda
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 LHCZ. Fodor et al, JHEP 0203:014(02)
C.R. Allton et al, hep-lat/0204010
F. Karsch, Nucl. Phys. A698, 199c(02).
LHC ?RHICSPS
6 ISMD, Berkeley, Aug 4 9, 2007 Kai Schweda
Chemical Freeze - out
ISMD, Berkeley, Aug 4 9, 2007 Kai Schweda
Hadron Yield Ratios
1) At RHIC:
Tch = 160 ± 10 MeV
B = 25 ± 5 MeV
2) S = 1.
The hadronic system is thermalized at RHIC.
3) Short-lived resonances show deviations.
There is life after chemical freeze-out.
RHIC white papers - 2005, Nucl. Phys. A757, STAR: p102; PHENIX: p184;Statistical Model calculations: P. Braun-Munzinger et al. nucl-th/0304013.
8 ISMD, Berkeley, Aug 4 9, 2007 Kai Schweda
Chemical Freeze-Out vs Energy
A. Andronic et al., NPA 772 (2006) 167.
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 !
B decreases, B = 1MeV at LHC
Nearly net-baryon free !
9 ISMD, Berkeley, Aug 4 9, 2007 Kai Schweda
Baryon Ratios
Compilation: N. Xu
With increasing energy:
• Baryon ratios approach unity
• At LHC, pbar / p 0.95
challenge,
need 1% precision to
address net-baryon
transport !
10 ISMD, Berkeley, Aug 4 9, 2007 Kai Schweda
Partonic Collectivity
11 ISMD, Berkeley, Aug 4 9, 2007 Kai Schweda
Elliptic Flow
Theory points: C.M. Ko – last call for predictions, CERN, May 2007.
“Elliptic flow is larger for
pions but smaller for
protons at LHC than at
RHIC”.
This is expected from simple, hydro-like blast-wave fits !
larger collective flow: mass ordering more pronounced !
12 ISMD, Berkeley, Aug 4 9, 2007 Kai Schweda
Collectivity Energy Dependence
Collectivity parameters <T>
and <v2> increase with energy
Two extreme secenarios:
(a) Tfo Tch AND T 0.8
pure partonic
collectivity at LHC!
(b) Tfo Tch , T 0.3
no collectivity,
no QGP !
ISMD, Berkeley, Aug 4 9, 2007 Kai Schweda
Quark Masses
1) Higgs mass: electro-weak symmetry breaking. (current quark mass)
2) QCD mass: Chiral symmetry breaking. (constituent quark mass)
Strong interactions do not
affect heavy-quark masses.
Important tool for studying properties of the hot/dense medium at RHIC and LHC.
Test pQCD predictions at RHIC and LHC.
Total quark mass (MeV)
X. Zhu, M. Bleicher, K.S., H. Stoecker, N. Xu et al., PLB 647 (2007) 366.
14 ISMD, Berkeley, Aug 4 9, 2007 Kai Schweda
Charm Correlations
c-cbar are correlated
• Pair creation: back to back
• Gluon splitting: forward
• Flavor excitation: flat
Correlations vanish
frequent interactions
among partons !
probe light-quark
thermalization !
Pythia calcs.: G. Tsiledakis.
15 ISMD, Berkeley, Aug 4 9, 2007 Kai Schweda
Hadronic Re-scattering
Hadronic re-scattering can not completely wash out DD-correlations
Frequent partonic re-scattering needed light quark
thermalization !X. Zhu, M. Bleicher, K.S., H. Stoecker, N. Xu et al., PLB 647 (2007) 366.
16 ISMD, Berkeley, Aug 4 9, 2007 Kai Schweda
J/ Production
suppression,compared to scaled p+p
regeneration,enhancement
Low energy (SPS): few ccbar quarks in the system suppression of J/
High energy (LHC): many ccbar pairs in the system enhancement of J/
Signal of de-confinement + thermalization of light quarks !
(SPS)
P. Braun-Munzinger and J. Stachel, Nature 448 (2007) 302.
17 ISMD, Berkeley, Aug 4 9, 2007 Kai Schweda
Predictions for LHC
large ccbar production at
LHC
corona effects negligible
regeneration of J/
dominates
striking centrality
dependence
Signature for QGP
formation !
Initial conditions at LHC ?
A. Andonic et al., nucl-th/0701079.
cc
18 ISMD, Berkeley, Aug 4 9, 2007 Kai Schweda
Pb+Pb
ccc / D :
p+p
Multiply Heavy-flavored Hadrons
F. Becattini, Phys. Rev. Lett. 95, 022301 (2005);P. Braun-Munzinger, K. Redlich, and J. Stachel, nucl-th/0304013.
Statistical hadronization
- de-confined heavy-quarks
- equilibrated heavy-quarks
Enhancement up to x1000 !
Measure cc, cc, Bc, (ccc)
Need total charm yields
Probe deconfinement and
thermalization @ LHC
QGP !
Quarks and gluons hadrons
c
c c
x1000
19 ISMD, Berkeley, Aug 4 9, 2007 Kai Schweda
Heavy Quark Production
1) Charm x 10
2) Beauty x 100
3) Heavy-quarks abundantly produced at LHC !STAR data: A. Suaide, P. Djawothoto QM2006;Calcs.: R. Vogt.
20 ISMD, Berkeley, Aug 4 9, 2007 Kai Schweda
ATLAS CMS
Low – momentum
CMS/ATLAS: Si only tracking
CMS: pT > 0.150 GeV
Mid Rapidity Performance
CMS: TDR.v2, CERN-LHCC-2007-009; ATLAS: B. Cole, SQM2007; ALICE: PPR.vol.II, J. Phys. G 32 (2006) 1295.
ALICE: large momentum coverage in full azimuth
address bulk properties !
characterize Quark Gluon Plasma !
21 ISMD, Berkeley, Aug 4 9, 2007 Kai Schweda
J/ e+ + e- Reconstruction
J/ e+ + e-
identify electrons
through their transition
radiation
Precise
Measurement of
Quarkonia !
J/: c c : b b
22 ISMD, Berkeley, Aug 4 9, 2007 Kai Schweda
Measure secondary vertex
Direct reconstruction of D0
precise measurement
of total heavy-quark
yield
address heavy – quark
collectivity !
D Meson Performance
ALICE: PPR.vol.II, J. Phys. G 32 (2006) 1295.
23 ISMD, Berkeley, Aug 4 9, 2007 Kai Schweda
Summary
Bulk properties at LHC:
dN / d 1000 – 3000
Tch 160 ± 10 MeV, B 0 – 5 MeV
Tfo Tch all collectivity from partonic stage
<T> = 0.8 ± 0.05 (c), <v2> 0.08
Measure spectra, correlations and v2 of:
D0, D+, Ds, J/b,
to identify and characterize QGP !
ALICE is well suited for these studies
