heavy - flavor (c,b) collectivity at rhic and lhc
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1 USTC, Hefei, Nov 22, 2005
HeavyFlavor (c,b) Collectivity
at RHIC and LHC
Kai Schweda, University of Heidelberg
A. Dainese, X. Dong, J. Faivre, Y. Lu, H.G. Ritter, L. Ruan,A. Shabetai, P. Sorensen, N. Xu, H. Zhang, Y. Zhang.
2 USTC, Hefei, Nov 22, 2005
Outline
1) Introduction
2) Multi-strange baryons elliptic flow
3) Heavy-quark Collectivity
4) Summary
3 USTC, Hefei, Nov 22, 2005
Quark Gluon Plasma
Source: Michael Turner, National Geographic (1996)
Quark Gluon Plasma:
(a) Deconfined and
(b) thermalized state of quarks and gluons
Study partonic EOS at RHIC(?) Probe thermalization using heavy-quarks
4 USTC, Hefei, Nov 22, 2005
Phase Diagram
5 USTC, Hefei, Nov 22, 2005
Heavy Ion CollisionsHeavy Ion Collisions
PCM & clust. hadronization
NFD
NFD & hadronic TM
PCM & hadronic TM
CYM & LGT
string & hadronic TM
1) Initial condition: 2) System evolves: 3) Bulk freeze-out:
- baryon transfer - parton/hadron expansion - hadronic dof
- ET production - interaction cease
- Partonic dof Tth, <T>
Time
Plot: Steffen A. Bass, Duke University
Heavy-Flavor , K, p
USTC, Hefei, Nov 22, 2005
7 USTC, Hefei, Nov 22, 2005
The STAR Detector
Coils
Silicon Vertex Tracker
E-M Calorimeter
Trigger Barrel
Time Projection Chamber
Forward Time Projection Chamber
Electronics Platforms
Magnet
8 USTC, Hefei, Nov 22, 2005
Peripheral Event
STARSTAR
Au + Au Collisions at RHICAu + Au Collisions at RHIC
(real-time Level 3)
9 USTC, Hefei, Nov 22, 2005STARSTAR
Mid-Central Event
Au + Au Collisions at RHICAu + Au Collisions at RHIC
(real-time Level 3)
10 USTC, Hefei, Nov 22, 2005
Au + Au Collisions at RHICAu + Au Collisions at RHIC
STARSTAR
Central Event
(real-time Level 3)
11 USTC, Hefei, Nov 22, 2005
Particle IdentificationParticle Identification
Reconstruct multi-strange resonances in 2 acceptance of STAR!
12 USTC, Hefei, Nov 22, 2005
Pressure, Flow, …Pressure, Flow, …
pdVdUd Thermodynamic identity
– entropy p – pressureU – energy V – volume= kBT, thermal energy per dof
In A+A collisions, interactions among constituentsand density distribution lead to: pressure gradient collective flow
number of degrees of freedom (dof) Equation of State (EOS) cumulative – partonic + hadronic
13 USTC, Hefei, Nov 22, 2005
1) Compared to 1) Compared to , , KK, and , and p,p, multi-strange particles multi-strange particles ,, are found at lower <are found at lower <TT>>
but higher T ~ Tbut higher T ~ Tchch
Collectivity prior to Collectivity prior to hadronization hadronization
2) Sudden single freeze-out*:2) Sudden single freeze-out*:Resonance decays lower TResonance decays lower Tfofo
for (for (, , KK, , pp)) Collectivity prior to Collectivity prior to
hadronizationhadronization
Partonic Partonic Collectivity ?Collectivity ?
Kinetic Freeze-out at RHIC
Data: Data: STAR preliminary Au+Au@200GeV: Nucl. Phys. A715, 129c(2003).*A. Baran, W. Broniowski and W. Florkowski; nucl-th/0305075
STAR Preliminary
Disentangle collective flow (T) and random walk (T)
14 USTC, Hefei, Nov 22, 2005
Anisotropy Parameter v2
y
x
py
px
coordinate-space-anisotropy momentum-space-anisotropy
y2 x 2
y 2 x 2v2 cos2 , tan
1(pypx)
Initial/final conditions, EoS, degrees of freedom
15 USTC, Hefei, Nov 22, 2005
v2 in the Low-pT Region
P. H
uo
vi ne
n, p
r ivate
com
mu
nica
t i on
s, 20
04
- Minimum bias data! At low pT, model result fits mass hierarchy well!- Details does not work, need more flow in the model!
16 USTC, Hefei, Nov 22, 2005
Collectivity, Deconfinement at RHIC
- v2, spectra of light hadrons and multi-strange hadrons - scaling with the number of constituent quarks
At RHIC, it seems we have:
Partonic Collectivity
Deconfinement
Thermalization ?
PHENIX: PRL91, 182301(03) STAR: PRL92, 052302(04)
S. Voloshin, NPA715, 379(03)Models: Greco et al, PRC68, 034904(03)X. Dong, et al., Phys. Lett. B597, 328(04).….
17 USTC, Hefei, Nov 22, 2005
Partonic Collectivity at RHIC
1) Copiously produced hadrons freeze-out: Tfo = 100 MeV, T = 0.6 (c) > T(SPS)
2) Multi-strange hadrons freeze-out: Tfo = 160-170 MeV (~ Tch), T = 0.4 (c)
3) Multi-strange v2: Multi-strange hadrons and do flow!
4) Constituent Quark scaling: Seems to work for v2 and RAA (RCP)
Deconfinement &Partonic (u,d,s) Collectivity !
18 USTC, Hefei, Nov 22, 2005
Heavy-Flavor Quarks
Plot: B. Mueller, nucl-th/0404015.
Symmetry is broken:
QCD dynamical mass
EW Higgs mass
Even in a QGP, charm and
beauty quark-mass heavy !
Heavy-flavor (c,b) are
good probes !
If heavy quarks flow:
frequent interactions
among all quarks
light quarks (u,d,s)
likely to be thermalizedPlot: B. Mueller, nucl-th/0404015.
Mas
s (M
eV/c
2 )
106
105
104
103
102
10
1
19 USTC, Hefei, Nov 22, 2005
Charm-quark Elliptic Flow
V. Greco et al., PLB 595(2004)202
Coalescence approach
Large X-sec needed to reach large v2 → Charm quark flows →Indication of light flavor thermal equilibrium!Theoretical justification of the large cross section?
AMPT transport model
B. Zhang et al., nucl-th/0502056
20 USTC, Hefei, Nov 22, 2005
The key point is to determine
Heavy-Flavor Collectivity
21 USTC, Hefei, Nov 22, 2005
V. Greco et al.PLB 595(2004)202
B. Zhang et al.nucl-th/0502056
Non-photonic electron v2
c (b) e + X
Large syst. uncertainties due to large background
Experimental data do not agree at 2<pT(e)<5 GeV/c!
v2(e) favors non-zero v2(c) at pT(e)<2 GeV/c.
22 USTC, Hefei, Nov 22, 2005
D0 Reconstruction in STAR
• D0 + K, BR = 3.8%, c = 124m
• calculate invariant mass in + K system
• Peak around 1.86 GeV/c2
• Large combinatorial background
Large stat. and syst. uncertainties
Need precise track information !
Need precise pointing device !
Central Au + Au collisions in STAR
TPC only
23 USTC, Hefei, Nov 22, 2005
STAR Detector Upgrade
• D0 K + c = 123m
• Measure decay vertex,
50m
• enhance S/B by factor 100
precise heavy-flavor
measurements !
Full Barrel MRPC - TOF Heavy Flavor Tracker
Active Pixel Sensors: M. Winter et al., IReS/LEPSI, Strasbourg.
24 USTC, Hefei, Nov 22, 2005
Flow Measurements
• Au + Au, 50M central events
• D0 K +
• Expected statistical
uncertainties small
Probe charm quark flow !
Also: Measure Ds +
D0 simulations: A. ShabetaiD0 v2-predictions: D. Molnar, J. Phys. G31, S421.
25 USTC, Hefei, Nov 22, 2005
The Alice Detector @ LHC
TPC: main tracking device
ITS: high spatial resolution
TRD: good electron PID (high pion rejection)
ToF: extend PID to large pT
26 USTC, Hefei, Nov 22, 2005
ALICE @ LHC : D0 K-+
|y| < 1 and pt > 1 GeV/c • Pb + Pb central, 1st year
• D0 K +
• Expected stat. + syst.
uncertainties small
Probe heavy-flavor flow !
D0 simulations: A. Dainese, nucl-ex/0510082.
Other (possible?) channels:
c pK (BR ~ 5%)
c K0, K+
27 USTC, Hefei, Nov 22, 2005
J/Enhancement at LHC Statistical hadronization
strong centrality dependence
of J\ yield at LHC
Need total charm yields !
Measure D0, D±, c, c
Probe deconfinement
and thermalizationCalculations:P. Braun Munzinger, C. Redlich,and J. Stachel, nucl-th/0304013.
28 USTC, Hefei, Nov 22, 2005
Multiply Heavy-flavored Hadrons
F. Becattini, Phys. Rev. Lett. 95, 022301 (2005);P. Braun Munzinger, C. 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
QGP !
Quarks and gluons hadrons
Pb+Pb
ccc / D :
p+p
x1000
29 USTC, Hefei, Nov 22, 2005
Summary
Multi-strange hadrons and flow
Partonic collectivity at RHIC
Deconfinement at RHIC
Measure spectra, elliptic flow and yields of
D0, D, D+s, C, J/, B±
Probe (u,d,s)-quark thermalization
ALICE: TPC + Vertex + TRD (+ToF)
30 USTC, Hefei, Nov 22, 2005
Building Blocks of Matter
Elementary particles –
microscopic laws:
Electroweak force
Hunt for theStrong force
Gravitation
Masses are free
parameters !
Origin of Mass ?
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