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Physics with identified particles at STAR. L ijuan Ruan for the STAR Collaboration ( Lawrence Berkeley National Laboratory ). Outline: STAR Detector configuration Motivation -- What has been observed at RHIC -- What still needs to be addressed - PowerPoint PPT Presentation
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Lijuan Ruan QM2006, Shanghai, Nov. 14, 2006 1
Physics with identified particles at STAR
Outline:• STAR Detector configuration • Motivation -- What has been observed at RHIC -- What still needs to be addressed• Highlight results of identified particle physics from STAR -- Low pT: bulk property -- Intermediate pT: coalescence -- High pT: parton energy loss
• Summary
Lijuan Ruan for the STAR Collaboration (Lawrence Berkeley National Laboratory)
Lijuan Ruan QM2006, Shanghai, Nov. 14, 2006 2
The STAR Detector
MagnetMagnet
CoilsCoils
Central Central TriggerTriggerBarrel Barrel (CTB)(CTB)
ZCalZCal
Time Time Projection Projection
ChamberChamber(TPC)(TPC)
Year 2000Year 2000
Barrel EM Cal Barrel EM Cal (BEMC)(BEMC)
Silicon Vertex Silicon Vertex Tracker (SVT)Tracker (SVT)Silicon Strip Silicon Strip Detector (SSD)Detector (SSD)
FTPCFTPCEndcap EM CalEndcap EM CalFPDFPD
TOFp, TOFrTOFp, TOFr
FPDFPD
Year 2001+Year 2001+
PMD
Large acceptance: 2 coverage at mid-rapidity
Future upgrade: Time of Flight, DAQ1000, Heavy Flavor Tracker, Muon Telescope DetectorFuture upgrade: Time of Flight, DAQ1000, Heavy Flavor Tracker, Muon Telescope Detector
Lijuan Ruan QM2006, Shanghai, Nov. 14, 2006 3
The theory-experiment comparison suggests that central Au+Au collisions at RHIC produce dense, rapidly
thermalizing matter characterized by • Initial energy densities above the critical values predicted by lattice
QCD for establishment of a Quark-Gluon Plasma• Nearly ideal fluid flow, marked by constituent interactions of very short
mean free path, established most probably at a stage preceding hadron formation
• Opacity to jets
What has been observed at RHIC
STAR Collaboration, NPA 757,102 (2005)
Lijuan Ruan QM2006, Shanghai, Nov. 14, 2006 4
What still needs to be addressed • EOS and thermalization
• Freeze out properties
• v2 scaling and baryon enhancement: coalescence
• Jet quenching: parton energy loss
• Energy dependence: testing model prediction (coalescence and jet quenching)
• Heavy flavor yields and flow: color screening and partonic collectivity.
• Thermometers: dilepton, photon
• heavy quarkonium species.
• Jet fragments tagged by a hard direct photon, a heavy flavor
• forward jet correlation: CGC
Energy and system size dependence of v2, fluctuation
Three particle correlation
K p at low pT, light nuclei production
Correlation and fluctuation
K*, , KS, Λ, , , , K, p v2 and RCP
Baryon/meson-charged hadron correlation
PID spectra at high pT Pbar and pion: Casimir factor
CA/CF=9/4 Charm and bottom: dead cone
Energy dependence of identified particle production
Topic in black color, see M. Calderon’s talk
Lijuan Ruan QM2006, Shanghai, Nov. 14, 2006 5
Elliptic flow and its fluctuation
Consistent v2/ scaling for all energies and collision systems. S. Voloshin’s talk(2.4)
First measurement of v2 fluctuation.
v2/<v2> ~36% observed.
P. Sorensen’s talk(2.4)
central
peripheral
Lijuan Ruan QM2006, Shanghai, Nov. 14, 2006 6
v1 measurement
v4/v22 measurement, see Y. Bai’s talk(2.4)
v1 depends on energy, not on system size. G. Wang’s talk(3.4)
Lijuan Ruan QM2006, Shanghai, Nov. 14, 2006 7
STAR preliminary
0-12% 200 GeV Au+Au
Hard-soft correlations
1. Hard-soft: away-side spectra approaching the bulk.
2. Mach-cone shock waves: a fast thermalization mechanism through dispersing energy into collective modes of shock waves.
Mediumaway
near
deflected jets
away
near
Medium
mach cone
M. Horner’s talk(3.2)
STAR Collaboration, PRL 95,152301 (2005)
Lijuan Ruan QM2006, Shanghai, Nov. 14, 2006 8
Three particle correlation
Two Analysis Approaches:• Cumulant Method
1) Unambiguous evidence for three particle correlations.
• Jet-Flowbackground Method
1) Within a model dependent analysis, evidence for conical emission in central Au+Au collisions
C. Pruneau ’s talk(1.3) J. Ulery’s poster(44)
pTtrig=3-4 GeV/c
pTassoc=1-2 GeV/c
off-
diag
onal
pro
ject
ion
d+Au
0-12% Au+Au
=(12)/2
Δ2
Δ1 Δ1
0-12% Au+Au: jet v2=0
Δ2
Lijuan Ruan QM2006, Shanghai, Nov. 14, 2006 9
What still needs to be addressed
• EOS and thermalization
• Freeze out properties
• v2 scaling and baryon enhancement: coalescence
• Jet quenching: parton energy loss
• Energy dependence: testing model prediction (coalescence and jet quenching)
Energy and system size dependence of v2, fluctuation
Three particle correlation
K p at low pT, light nuclei production
Correlation and fluctuation
K*, , KS, Λ, , , , K, p v2 and RCP
Baryon/meson-charged hadron correlation
PID spectra at high pT Pbar and pion: Casimir factor
CA/CF=9/4 Charm and bottom: dead cone
Energy dependence of identified particle production
Lijuan Ruan QM2006, Shanghai, Nov. 14, 2006 10
Fluctuation and freeze-out dynamics at RHIC
Energy scan to map out the critical point by measuring K/, p/ fluctuation and identified particle spectra in the future.
S. Das’s poster(107)
STAR preliminary
STAR Preliminary
5% central10% centralMin-Bias
Kp thermal fit
A. Iordanova’s poster(04)
Tc
h (G
eV
)
μB (MeV)
STAR PreliminarySTAR preliminary
K/ fluctuation: similar in 62 and 200 GeV
Positive long range correlation observed B. Srivastava poster(101)
Lijuan Ruan QM2006, Shanghai, Nov. 14, 2006 11
Soft physics measurements vs dNch/d
nucl-ex/0505014 Lisa et al.
Tkin,<pT>, HBT Radii are strongly correlated with (dNch/dη).
STAR Preliminary
A. Iordanova’s poster(04)
STAR Preliminary
D. Das’s poster(21)
Lijuan Ruan QM2006, Shanghai, Nov. 14, 2006 12
New direction
imagingvs Abeam
HBT measurement
Systematics!: s, mT, A+A, pair PID: consistent, detailed map of space-momentum substructure
mT scaling for space momentum correlation
P. Chaloupka’s poster(106) R. Witt’s talk(3.1)
D. Das’s poster(21)
mT (GeV/c)
Rin
v (
fm)
STAR preliminary
Cu+Cucentral
Cu+Cuperipheral
STAR preliminary
Exotic systems!Shifts from non-id!
*(1530)
Lijuan Ruan QM2006, Shanghai, Nov. 14, 2006 13
What still need to be addressed
• EOS and thermalization
• Freeze out properties
• v2 scaling and baryon enhancement: coalescence
• Jet quenching: parton energy loss
• Energy dependence: testing model prediction (coalescence and jet quenching)
Energy and system size dependence of v2, fluctuation
Three particle correlation
K p at low pT, light nuclei production
Correlation and fluctuation
K*, , KS, Λ, , , , K, p v2 and RCP
Baryon/meson-charged hadron correlation
PID spectra at high pT Pbar and pion: Casimir factor
CA/CF=9/4 Charm and bottom: dead cone
Energy dependence of identified particle production
Lijuan Ruan QM2006, Shanghai, Nov. 14, 2006 14
v2 of strangeness hadrons and nuclei in 200 GeV Au+Au collisions
Intermediate pT (0.7<pT/n<2GeV/c)
• KS K* Λ v2: follow NQ scaling.
• The centrality dependence of v2: similar to minbias.
• Heavy particle: d follows A scaling, 3He follows A scaling at low pT, maybe deviate at higher pTneed more statistics.S. Blyth’s talk ()(3.1)
H. Liu’s talk(3.4)
Y. Bai’s talk (KSΛ)(2.4) X. Dong’s poster (K*)(75)
STAR preliminarySTAR preliminary
STAR preliminary
0-80% Au+Au
Lijuan Ruan QM2006, Shanghai, Nov. 14, 2006 15
-h correlations-h correlations
__ifif Ω: sss (φ ss) at intermediate pT come mostly from TTT (TT) No near side correlation! Not consistent with data.
Same-side yield ≠0:Omegas with pOmegas with pTT less less
than 4.5 GeV/c contain than 4.5 GeV/c contain non-thermal non-thermal s-quarks: made in jets? s-quarks: made in jets?
Λ - h correlations are similar
__ifif Ω: sss (φ ss) at intermediate pT come mostly from TTT (TT) No near side correlation! Not consistent with data.
Same-side yield ≠0:Omegas with pOmegas with pTT less less
than 4.5 GeV/c contain than 4.5 GeV/c contain non-thermal non-thermal s-quarks: made in jets? s-quarks: made in jets?
Λ - h correlations are similar
J. Bielcikova’s talk(3.1)
R. C. Hwa et al., nucl-th/0602024.
Lijuan Ruan QM2006, Shanghai, Nov. 14, 2006 16
What still need to be addressed
• EOS and thermalization
• Freeze out properties
• v2 scaling and baryon enhancement: coalescence
• Jet quenching: parton energy loss
• Energy dependence: testing model prediction (coalescence and jet quenching)
Energy and system size dependence of v2, fluctuation
Three particle correlation
K p at low pT, light nuclei production
Correlation and fluctuation
K*, , KS, Λ, , , , K, p v2 and RCP
Baryon/meson-charged hadron correlation
PID spectra at high pT Pbar and pion: Casimir factor
CA/CF=9/4 Charm and bottom: dead cone
Energy dependence of identified particle production
Lijuan Ruan QM2006, Shanghai, Nov. 14, 2006 17
Gluon contribution factor to hadrons
1. q jets or g jets gluon jet contribution to protons is significantly larger than to pions at high pT in p+p collisions at RHIC; pbar/ < 0.1 from quark jet fragmentation at low beam energy . STAR Collaboration, PLB 637, 161 (2006).
2. From Kretzer fragmentation function, the g/q jet contribution is similar to AKK. S. Kretzer, PRD 62, 054001 (2000).
200 GeV p+p
Lijuan Ruan QM2006, Shanghai, Nov. 14, 2006 18
Particle ratios in 200 GeV Au+Au
At pT>5 GeV/c at RHIC at 200 GeV:1. p(pbar)/ are larger than the ratios from quark jet.
2. Expectation: pbar/ (Au+Au) < pbar/ (d+Au, p+p). (X.N. Wang, PRC 58, 2321,
(1998))
3. p(pbar)/ (Au+Au) ~ p(pbar)/ (d+Au, p+p). new experimental phenomena R.J. Fries et al., PRC 68, 044902 (2003); R.C. Hwa et al., PRC 70, 024905 (2004); DELPHI Collaboration, Eur. Phy. J. C 5, 585 (1998), Eur. Phy. J. C 17, 207 (2000); W. Liu et al., nucl-th/0607047.
gluon jet
quark jet
quark jet
STAR Collaboration, PRL 97 (152301) 2006
B. Mohanty’s talk(2.2)
Lijuan Ruan QM2006, Shanghai, Nov. 14, 2006 19
Energy dependence of RAA (RCP)
Steeper initial jet spectra ?Or Color charge dependence ?At same pT : ~ 3 difference in xT.Q. Wang and X.N. Wang, PRC 71, 014903 (2005)
At 1.5< pT < 6 GeV/c: RCP(p+pbar) > RCP()At pT>6 GeV/c, RCP(p+pbar) ~ RCP()Similar to 200 GeV Au+Au collisions.
B. Mohanty’s talk(2.2)
Lijuan Ruan QM2006, Shanghai, Nov. 14, 2006 20
Energy dependence of particle composition
system size dependence B. Mohanty’s talk(2.2)
In 62 and 200 GeV Au+Au collisions:
1. Λ/KS ratio: similar peak positions.2. p(pbar)/ ratios: similar shapes at pT>2 GeV/c.
STAR preliminary
Lijuan Ruan QM2006, Shanghai, Nov. 14, 2006 21
Discussion: recombination/coalescence model
Differences between data and current models: • The p(pbar)/ ratios in energy dependence at pT>2 GeV/c. R.J. Fries et al., PRC 68, 044902 (2003).
• The Ω/Ф ratio at pT>4 GeV/c. R. C. Hwa et al., nucl-th/0602024.
• The Ω-h correlation with 2.5<pT(trigger)<4.5 GeV/c and 1.5<pT(associate)<pT(trigger) GeV/c. R. C. Hwa et al., nucl-th/0602024.
S. Blyth’s talk(3.1)
B. Mohanty’s talk(2.2)
J. Bielcikova’s talk(3.1)
STAR preliminary
Lijuan Ruan QM2006, Shanghai, Nov. 14, 2006 22
Summary
• EOS and thermalization: 1) Significant v2 fluctuation 2) 3 particle jet correlation: evidence
for conical emission.
• Coalescence 1) Similar shape of p(pbar)/ ratios at
pT>2 GeV/c between 62 and 200 GeV 2) The / ratio peaks at pT~4 GeV/c 3) Significant -h correlation at
intermediate pT.
• Jet quenching: parton energy loss
The common suppression of pbar and pion new experimental phenomena
Energy and system size dependence of v2, fluctuation
Three particle correlation
K p at low pT, light nuclei production Correlation and fluctuation
K*, , KS, Λ, , , , K, p v2 and RCP
Baryon/meson-charged hadron correlation
PID spectra at high pT
Pbar and pion: Casimir factor CA/CF=9/4 Charm and bottom: dead cone
Energy dependence of identified particle production
Thanks to the STAR Collaboration!
Lijuan Ruan QM2006, Shanghai, Nov. 14, 2006 23
STAR QM2006 parallel talks• J.H. Chen --- Spin alignment of vector mesons (K*, ) in Au+Au and p+p collisions at 200 GeV.• H. Liu (3.4) --- Yields and elliptic flow of d(dbar) and 3He(anti-3He) in Au+Au collisions at 200 GeV.• G. Wang (3.4) --- Incident-energy and system-size dependence of directed flow.
• Y. Bai (2.4) --- v2, v4 centrality, pT and particle-type dependence in Au+Au collisions at RHIC
• I. Selyuzhenkov (3.4) --- Global polarization of Lambda hyperons in Au+Au collisions at RHIC
• S. Voloshin (2.4) --- Energy and system size dependence of elliptic flow and v2/ε scaling
• J. Putschke (1.3) --- Near-side correlations of high-pT hadrons from STAR
• B. Mohanty (2.2) --- Properties of particle production at large transverse momenta in Cu+Cu and Au+Au collisions at RHIC energies
• M. Horner (3.2) --- Low and intermediate pT azimuthal di-hadron correlations from 200 GeV Au+Au collisions measured in STAR
• J. Bielcikova (3.1) --- High pT azimuthal and pseudorapidity correlations with strange baryons and mesons at RHIC
• X. Lin (2.2) --- Study B and D contributions via azimuthal correlations between non-photonic electrons and charged hadrons• C. Zhong (2.1) --- Scaling of charm integrated cross section and modification of its transverse momentum spectra in d+Au and
Au+Au collisions at RHIC• R. Witt (3.1) --- 0(1530) production in heavy ion collisions and its implications for t(therm-chem)• S. Blyth (3.1) --- A measurement of the centrality dependence of the N()/N() ratio and anisotropic flow • P. Djawotho (3.1) --- Quarkonium production at STAR• S. Chattopadhyay (3.2) --- Azimuthal -charged hadron correlations in d+Au and p+p collisions from STAR at 200 GeV• M. Russcher (3.3) --- Direct photon production in p+p and d+Au collisions at 200 GeV from STAR• P. Sorensen (2.4) --- First measurements of elliptic flow fluctuations• C. Pruneau (1.3) --- Is there a Mach-cone? – Three particle azimuthal correlations from STAR• L. Molnar (1.1) --- Probing small-x gluons and large-x quarks: jet-like correlations between forward and mid-rapidity in p+p, d+Au and
Au+Au collisions at STAR• J. Wu (1.4) --- A barrel TOF for STAR at RHIC• A. Rose (1.4) --- A heavy flavor tracker for STAR
Lijuan Ruan QM2006, Shanghai, Nov. 14, 2006 24
STAR QM2006 posters
• P. Chaloupka --- - correlations in d+Au and Au+Au collisions at STAR• S. Das --- Strangeness fluctuations at RHIC• T. Tarnowsky --- Energy and system size dependence study of percolation phase transition• R. Raniwala --- Elliptic flow of inclusive photons and charged particles in Cu+Cu collisions at 200 GeV• J. Ulery --- Are there Mach cones in heavy ion collisions? Three particle azimuthal correlations in STAR• J. Bouchet --- Performance studies of the silicon detectors in STAR towards microvertexing of rare decays.• M. Cosentino --- Upsilon measurement in STAR• A. Iordanova --- System size dependence of freeze-out properties at RHIC• D. Das --- Identical Meson Interferometry in STAR Experiment• X. Dong --- K* production in Au+Au collisions at RHIC• H. Gose --- Proton femtoscopy in STAR• A. Knospe --- Strangeness and heavy flavor production
• G. Lin --- The inclusive photon and charged particle v2 at 200 GeV in Au+Au and Cu+Cu collisions.
• R. Longacre --- scaled correlation signals which increase with centrality of Au+Au collisions at 200 GeV• T. Nayak --- Net charge fluctuations using high order cumulants• P. Netrakanti --- Mechanism of particle production in p+p and d+Au collisions• M. Shao --- A study of the intrinsic time resolution of MRPC used in STAR-TOF • S. Monika --- Energy and system size dependence of photon production• B. Srivastava --- Understanding the particle production mechanism with correlation studies using long and short
range correlations and the balance function• A. Timmins --- The centrality dependence of strange baryon and meson production in Cu+Cu and Au+Au relativistic
heavy ion collisions with 200 GeV
Lijuan Ruan QM2006, Shanghai, Nov. 14, 2006 25
STAR Collaboration
U.S. Labs: Argonne, Lawrence Berkeley, and Brookhaven National Labs
U.S. Universities: UC Berkeley, UC Davis, UCLA, Caltech, Carnegie Mellon, Creighton, Illinois-Chicago, Indiana, Kent State, MIT, MSU, CCNY, Ohio State, Penn State, Purdue, Rice, Texas A&M, UT Austin, Washington, Wayne State, Valparaiso, Yale
Brazil: Universidade de Sao Paolo
China: IHEP - Beijing, IPP - Wuhan, USTC,Tsinghua, SINAP, IMP Lanzhou
Croatia: Zagreb University
Czech Republic: Nuclear Physics Institute
England: University of Birmingham
France: Institut de Recherches Subatomiques Strasbourg, SUBATECH - Nantes
Germany: Max Planck Institute – Munich University of Frankfurt
India:Bhubaneswar, Jammu, IIT-Mumbai, Panjab, Rajasthan, VECC
Korea:Pusan Nat’l University
Netherlands:NIKHEF
Poland:Warsaw University of Technology
Russia: MEPHI – Moscow, LPP/LHE JINR – Dubna, IHEP – Protvino
Thanks!