Transcript 中国与RHIC-STAR的国际合作 马余刚，陈宏芳，程建平 中国RHIC-STAR合作组： 中国科大，清华大学，上海应物所， 华中师大，高能所，近物所 2005/6/28-29 2005/6/28-29 第59届东方论坛，上海 outline Chinese RHIC-STAR Group TOFr and Physics Results Impact of Chinese RHIC-STAR Group Physics with Full TOF Project Conclusion 2005/6/28-29 第59届东方论坛，上海.

中国与RHIC-STAR的国际合作
马余刚，陈宏芳，程建平
中国RHIC-STAR合作组：
中国科大，清华大学，上海应物所，
华中师大，高能所，近物所
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outline
Chinese RHIC-STAR Group
TOFr and Physics Results
Impact of Chinese RHIC-STAR Group
Physics with Full TOF Project
Conclusion
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Chinese RHIC-STAR Group
-History and present organization
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US-China Collaboration on STAR/ RHIC
 A STAR-China collaboration has been established (Six Institutions from China)
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University of Science and Technology of China, Hefei (USTC)
Tsinghua University
Shanghai Institute of Applied Physics (SINAP)
Central China Normal University, Wuhan (CCNU)
Institute of Modern Physics, Lanzhou (IMP)
Institute of High Energy Physics, Beijing (IHEP)
 Chinese collaborators are playing a major role in physics analyses involving
open charm, Cronin effect, and elliptic flow as part of STAR’s focus on studies
of a new state of matter (the quark-gluon plasma) at RHIC
 Chinese groups are leading in prototyping and development for a large-area
MRPC time-of-flight detector for STAR.
 This is the first major US-China collaboration on high energy nuclear physics
and we have had a very successful beginning.
 The STAR-China Time-of-Flight Construction Project has been covered under
the US-PRC HEP Agreement since 2001 to ensure smooth construction of the
TOF detector and operation of the STAR-China collaboration.
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Major Milestones of STAR-China TOF Project
 CCNU and IHEP joined STAR collaboration in 1999 for TOFp; SINAP, USTC,
Tsinghua and IMP joined STAR collaboration in Oct. 2001.
 USTC team began MRPC R&D in Aug. 2000 with the supports of NSFC,
STAR and other Chinese collaboration institutions.
 Joined in US/PRC Cooperative Agreement on High Energy Physics since
2001 (22nd Meeting)
 Prototype MRPC (multi-gap resistive plate) time-of-flight detectors,
produced jointly between USTC and Rice Univ. and operated successfully in
STAR (2002-3 and 2003-4 RHIC runs). Physics results on identified particle
spectra and on semi-leptonic charm decays have been published.
 Approval of "RHIC-STAR Physics and the Construction of Barrel STAR-TOF”
by the National Natural Science Foundation of China (Sept 10, 2004, Budget:
1.5M USD)
 Approval of the STAR TOF upgrade proposal by BNL Technical Advisory
Committee and Submission of the Proposal to DOE (July 2004)
 Technical Review of proposal by DOE, planned Aug. 2005
 Suppose DOE approval in Oct. 2005, full construction start October 2005
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MRPC TOF Barrel R&D
 RUN 2002-3: TOF installed in STAR
 24 MRPC modules produced at University of
Science Technology China
 6-channel front-end cards, with amplifiers
and discriminators, CAMAC read-out
2002
 Run 2003-4: TOF installed in STAR
 5 new modules from USTC and 5 from
Tsinghua University, Tsinghua developed
automated techniques for manufacturing
 24-channel front-end cards with amplifier and
discriminator
 RUN 2004-5, TOF installed in STAR,
 16 new modules from Tsinghua
 First time use of full on-board read-out
electronics: digitization of data on-board
 First use of ALICE PCI-PC based DAQ 2004
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G. Eppley et al.
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The STAR Barrel TOF MRPC Prototype
Prototype Tray
Construction
at Rice University
MRPC design developed at
CERN, built in USTC/China
28 MRPC
Detectors;
24 made at
USTC
FEE
Neighbor
CTB Tray
  70 ps, 2 meter path
Strong team including 6
Chinese Institutions in place
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EMC
Rails
Completed Prototype 28 module MRPC
TOF Tray installed in STAR Oct. ‘ 02 in
place of existing central trigger barrel tray
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batch production
40 MRPC production， more than 80％ of eligible rate , good
performance in on-line testing at RHIC-STAR (Tsinghua)
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Chinese Proposal to NSFC
Project Leader: Yu-Gang Ma (SINAP)
Deputy Leaders: Hongfang Chen (USTC)
Jian-Ping Cheng (Tsinghua)
Liaison person: Huanzhong Huang (UCLA)

Studies of the strong interaction matter at high
temperature/density and searching for QGP
(Yu-Gang Ma, SINAP) (SINAP, CCNU, USTC, Tsinghua etc.)
focus on the collective dynamics of rare particles, heavy quark
production, hadronic evolution dynamics and search for multi-quark
state particles

Design and Mass production of MRPC modules for STAR-TOF
(Jian-Ping Cheng, Tsinghua) (Tsinghua, USTC)
3840 MRPC for 120 tray, additional 6 tray (70% Tsinghua/30% USTC)

Quality control and calibration for STAR－TOF
(Xiao-Lian Wang, USTC) (USTC, Tsinghua)
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The Proposal of RHIC-STAR Full TOF Construction
Proposed major construction responsibilities:
 Chinese STAR Groups:
MRPC Production and Quality Assurance – NSFC/CAS/MoST
(Approved in Sept, 2004)
(Special thanks for Huanzhong, Nu, Zhangbu, Xinnian et al. for many important suggestions
and helps)
 US STAR Groups:
Electronics and Integration etc – DOE
Project Manager: G. Eppley
(with DOE)
Monetary Contributions:
China
~ US$2.5 M (US$ 1.5M from NSFC/CAS/MoST)
US- DOE ~ US$4.5 M
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STAR TOFr and Physics Results
TOF prototype:
1/120 coverage of Barrel STAR
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PID
TPC alone
TOF “alone”

k
p
TOF=110ps
TPC alone PID range:
pi/k ~0.6 GeV/c,
(pi,k)/p ~1.5GeV/c;
TOF “alone” PID range:
pi/k ~1.6GeV/c,
(pi,k)/p ~ 3.0GeV/c
m2
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m2
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Preliminary pion spectra till high pT
TPC+TOF:
 TPC:
 TOF:
 Pion: 0.2-~1.6GeV/c
 Pion: 0-~0.6GeV/c
 Kaon: 0.2-~0.6GeV/c  Kaon: 0.2-~1.6GeV/c
 Proton: 0.2-~1 GeV/c  Proton: 0.2-~3 GeV/c
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 TPC+TOF:
 Pion: 0.-~10 GeV/c
 Kaon: 0.2-~3GeV/c
 Proton: 0.2-~5 GeV/c
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Lepton decay from heavy quark
Electron identification
Electorns mixed with pions if
only dE/dx of TPC is used to
identify particles
Combined with
TOF，electrons
can be separated
from pions
cleanly
X. Dong, Z.B. Xu, LJ Ruan, J Wu et al
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RAuAu and RdAu of f
2.0
RdAu
1.6
2.5
Phi
kaon
pion
Proton
RdAu
2.0
RdAu or RAA
RdAu
d 2 N /( 2pT dpT dy )
pp

, TdAu  N bin /  inel
2 pp
TdAu d  inel /( 2pT dpT dy )
1.2
0.8
STAR Preliminary
0.4
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
2
PT (GeV/c )
•
1.5
1.0
RAA(60~80/pp)
RAA(05/pp)
______________
0.5
STAR Preliminary
0.0
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
2
PT (GeV/c )
RdAu of f is closer to that of p and k than that of p
•Particle production at intermediate pT region is sorted
by the particle’s type, not the mass
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Preliminary results v2
1. the elliptic flow of Φ-meson
gives similar behavior of Ks but
distinguish from Λ
2. a NCQ-scaling has been observed
in Φ-meson
3. error bars in higt pt range
(2.5GeV,5.0GeV) are still large
0-80%
STAR Preliminary data
AMPT calc.
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Impact of Chinese
RHIC-STAR Collaboration
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Organizing International workshop
Host:
 Aug 2002: 1st International CCAST Summer School and Workshop on “QCD and
RHIC Physics” in CCAST-WL, Beijing. Organized by Profs. X.L. Wang and P. F.
Zhuang. There were ~15 foreign speakers invited, ~100 participants
 Oct 2003, 1st STAR Regional Collaboration Meeting, USTC; ~10 STAR speakers
invited
 Aug 2004: 2nd International CCAST Summer School and Workshop on “QCD and
RHIC Physics” in CCAST-WL, Beijing. Organized by Profs. Y.G. Ma, E.K. Wang and
J.H. Fu. There were 19 foreign speakers and 22 domestic speakers, ~140
participants.
 Oct 2004: International Workshop on “Collective Dynamics in Relativistic Heavy Ion
Collisions” @ USTC, Organized by X.L. Wang and Nu Xu
 19－24 June 2005: 3rd International Workshop on “QCD and RICH Physics” was
organized by CCNU and CCAST et al.,, Wuhan; 20 foreign speakers, ~140
participants
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Talk @ Int. Conference
QM2006 in Shanghai:
 The proposal to host “Quark Matter 2006” in Shanghai was accepted
during QM2004 in Oakland. Shanghai Institute of Applied Physics and
Central China Normal University will co-organize the QM2006 in
Shanghai, preliminary date Nov 16-22, 2006
Co-chairs: Zhiyuan Zhu (SINAP) & Xu Cai (CCNU)
Honor Chair: T. D. Lee
Taks in some international conferences:
Conference Talks:
QM2004: one oral presentation (Ruan)
SQM2004: three oral presentations (Cai, Ruan, Ma)
ICEHP2004: one oral presentation (Wu)
QM2005: one Plenary Talk (Dong, from TOF phys results)
one parallel talk (Cai)
……
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Our excellent students
PhD Dissertations (incomplete statistics) :
Jinghua FU (CCNU): 获二○○五年全国优秀博士学位论文
Shengli HHUANG (USTC), Lijuan RUAN (USTC)，Zhixi LIU (CCNU)
Xing DONG (USTC):获二○○四年中国科学院院长奖学金特别奖
More PhD Students are involved in RHIC-STAR physics
Chinese Principal authors of STAR Publications or works:
Jinghua Fu et al.: Flow of Ks and  for 130GeV/c Au+Au (Phys. Rev. Lett. 89, 132301 (2002).)
Xin Dong et al. : electron spectra fro open Charm (nucl-ex/0407006), PRL94, 062301 (2005)
Lijuan Run et al.: Cronin Effect (nucl-ex /0309012 ), Phys Lett B 616, 8 (2005)
Lijuan Ruan (for the STAR Collaboration), π, K, p and production from Au+Au collisions at 62.4 GeV, J. Phys.
G: Nucl. Part. Phys. 31 S1029-S1033 (2005)
Xiangzhou Cai (for the STAR Collaboration) Production of K0s, Λ and Ξ from 200 GeV d+Au collisions at RHIC,
J . Phys. G: Nucl. Part. Phys. 31 S1015-S1018 (2005)
Ming Shao, Pion, Kaon, and (Anti-) Proton Production in Au+Au Collisions at \srt = 62.4 GeV, J.Phys. G31 (2005)
S85-S92
Shengli Huang et al.: azimuthal dependent fluctuation
Zhixu Liu et al.: flow of Ks and  for 63 GeV/c Au+Au
Guoliang Ma et al. : flow and spectra of f for 63 63 GeV/c Au+Au
Jinhui Chen et al., phi flow
Jiaxu Zuo et al., multi-strange partcile spactra,
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Physics with the
full coverage of
TOF
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STAR TPC + TOF (MC)
Central (top 10%) collisions
acceptance with TPC:
: ~ 60%
K: ~ 60%
p: ~ 50%
acceptance with TPC+TOF:
> 95% for all particles
S/N for f reconstruction will
increase by a factor of 5-10
 v2 measurement possible
Z. Liu, F. Liu, et al.
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STAR TPC + TOF
1) TOF will increase V0
reconstruction efficiency.
In the case of W, a factor
of 5 – 10 increase
expected in the region pT
~ 3-5 GeV/c!
2) TOF will also help future
D meson reconstruction –
increasing S/N ratios,
same way for other
resonances.
(D0 → K−+)
(D0-bar → K+−)
3) In the case for f, a factor
of 5-10 increase in S/N
ratio is expected.
H. Long et al.
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f=>K + + K -
(49.1%)
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STAR TPC + TOF
W v2 measurements
With TOF
w/o TOF
ideal
For integrated W v2 :
needs ~ few 106 MiniBias events.
More events without TOF
 Multi-years running.
pT dependence W v2:
for <20% around pT ~ 5 GeV/c,
needs ~ few 10th 106 MiniBias
events with TOF
 almost impossible without TOF in middle Pt
STAR 200 GeV results:
T = 0.45 GeV
dN/dy = 0.64, sum of W- and W+
< v2 > ~ 8%
all are usable events (1.5 -3 factor)
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TOF and  Hyperon
Embedded Data:
 reconstruction with and
without PID information!
A Factor of 3 !!
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Input spectrum:
T = 350 MeV f SB
 mt  exp mt / T 
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Chinese interests
Collective dynamics for rare particles
Heavy flavor quarks
Search for multi-quark state particles
Fluctuations
Correlation of rare particles
Hadronic evolution dynamics: resonance
…….
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Collective flow in partonic level:
Does the Recombination model work for heavy particles or strange quark?
how about flow of electron, f, W, D, J/ v2(p) ?
Need Full TOF for good efficiency and statistics
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Heavy flavor quark
•Initial condition
•J/ suppression
•Heavy quark energy loss
D0 Sensitivity in pT
Charm quark mostly produced
from the initial fusion of partons
(mostly gluons)
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Without TOF
With TOF
All pT
12M
2.6M
pT>2.
59M
23M
2>pT>4.
85M
42M
4>pT>6.
115M
115M
Important Measurement: Open Charm
TOF helps by a factor of ~5 (all PT)
TOF + Active Pixel Sensitive: x8
Other Open Charm States Possible only with TOF
Full Coverage needed
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Hadron evolution dynamics：resonance
Time scale of resonance state
Resonance
K*(892)
Decay channel
K
Branching Ratio % ~100
Width [MeV]
50.7
Life time [fm/c]
4
(770) f0(980)


~100 dominant
150
40 to 100
1.3
f(1020)
K K ee
49.2 0.3
4.46
40
(1232)
p
>99
~120
~1.6
(1520)
pK
22.5
15.6
13
(1385)

88.2
35.8
5.6
Increasing factor for statistical significance of the signal
Resonance Parent PT(GeV/c)
Kinetic Freeze-out
--- Interaction ceases
Chemical Freeze-out
--- formation of hadrons
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TPC+TOF
K*0
0-1
2.0
K*0
1-2
1.85
K*0
2-3
1.74
K*0
3-5
1.39
______________________
f(1020) 0-2
5.0
f(1020) 2-5
3.42
___________________________
(1520) 0-1.6
11.4
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Discoveries from Unexpected Areas?!
RHIC -- Frontier for bulk partonic matter formation
(quark clustering and rapid hadronization)
-- Factory for exotic particles/phenomena
Potential exotic particles/phenomena:
penta-quark states (uudds, uudds!)
di-baryons
H – (, uuddss)
[WW] (ssssss)
strange quark matter…….
penta-quark states?
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Search for multi-quark state particles
 Z.Y. Zhang et al., Phys. Rev. C 61, 065204 (2000); Phys. Rev. C66, 015205 (2002)
 3 body decay：
2 body decay：
A chrial SU(3) model and analyses of the symmetry properties of
two-baryon systems, some features:
A deeply bound, Eb ~ 100MeV;
A compact object, Rrms~0.63fm, <<Rd
may be six strange quark state rather than a di-baryon configuration
Phenomenological estimation (coalescence/statistical): yield 10-4_10-7/central
Au-Au; Full barrel TOF ~ 100M central AuAu events needed.
It is impossible to search di-omega in RHIC without STAR-TOF
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Conclusion
 We have strong team to collaborate with
RHIC-STAR, especially we have excellent
young students and excellent overseas
Chinese Americans
 Chinese Proposal to make B35arrel TOF has
been approved by NSFC, we are playing
leading role in STAR TOF upgrade
 We have great opportunity to do some new
and important physics with full TOF
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Quark Confinement？
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Recall Shanghai TOF meeting for
Discussion of NSFC
proposal draft, Jan 2003
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别有洞天
We have a new
scenery !
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Hadron spectra and Cronin effect
Traditional Cronin Effect is not the whole story at RHIC
TPC
With TOFr
STAR d+Au from
TOFr analysis
(USTC+BNL+RICE)
Results on KS, 
and f will reach
higher pT
(SINAP+UCLA)
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PID dependent Cronin effect
PID Cronin Effect
nucl-ex /0309012 )
With TOFr
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recentlyIn order to know about the elliptic flow of
f ,W, D, J/, Full TOF is necessary for good
efficiency and statistics.
In order to improve the measurements of Open
Charm, TOF helps by a factor of ~5 (all PT) and Full
Coverage needed
In order to investigate the hadronic evolution
dynamics, TOF increases important factor for
statistical significance of the resonance production.
TOF will significantly enhance the hyperon detection
efficiency. RHIC provides a unique environment for
possible production of multiply strange di-baryons.
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Heavy flavor （D-->e+X)
D meson and electron spectra :Dong, ZB, Ruan et al
The total photonic
backgrounds are
shown as solid lines.
Dashed lines depict
the various
contributing sources.
The fractions were
derived from
simulations.
Bottom:
Ratios of the inclusive
electrons over the
total back-grounds.
signal excesses are
visible with pT > 1
GeV/c.
With TOF tray
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(dN/dpT/<Nbin>)|cent/(dN/dpT/<Nbin>)|periph
Rcp of f for different collision system
STAR Preliminary
2.0
• yield suppression at intermediate PT
in central Au+Au collisions
RCP of  meson
1.8
1.6
1.4
•no clear suppression is showed in the
62.4 GeV Au+Au collision. It become
flat at PT>1GeV/c2
1.2
1.0
0.8
• RCP in d+Au collision is enhanced
0.6
0.4
0.2
0
1
2
32
4
5
PT(GeV/c )
200GeV d+Au RCP(0~20%/40~100%)
200GeV Au+Au RCP(0~5%/60~80%)
Low pT, RCP <1
High pT, RCP >1
It is difficult to draw some definite
conclusion due to the large error bar
62.4GeV Au+Au RCP(0~20%/60~80%)
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