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August 8, 2013Recent Results from the RHIC Beam Energy Scan Study emergent properties of matter with QCD degrees of freedomNu Xu(1) College of Physical Science & Technology, Central China Normal University, Wuhan, 430079, China (2) Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
Many Thanks to Organizers!
Introduction
- The QCD phase structure and STAR physics program
(2) Selected Recent Results
- RHIC Beam Energy Scan-I results
(3) Summary and Outlook
(4) CEE – CSR-External-Target-Facility Experiment
BRAHMS
RHIC
PHENIX
STAR
AGS
TANDEMS
Relativistic Heavy Ion ColliderBrookhaven National Laboratory (BNL), Upton, NYv = 0.99995c = 186,000 miles/sec
Au + Au at 200 GeV
Student Lecture, “Quark Matter 2006”, Shanghai, Nov. 14 - 20, 2006
Animation M. Lisa
TPC TOF TPC
TPC
K pd
π
e, μ
TOF
Log10(p)
Charged hadrons
Hyperons & Hyper-nuclei
MTD
HFT
Jets
EMC
Neutral particles
Jets & Correlations
High pTmuons
Heavy-flavor hadrons
Large, homogenous, collision energy independent acceptance
Multiple-fold correlations for the identified particles!
TE
RHIC, SPS
2
Large μB
FAIR, CSR
Tini, TC
LHC, RHIC
3
1
LHC+RHIC
sQGP properties
√sNN ~ 0.1 - 5 TeV
Future eRHIC
Cold nuclear matter properties
e + ion collisions
1
2
3
Emergent properties of QCD matter
Phase diagram: A map showsthat, at given degrees offreedom, how matterorganizeitself under externalconditions.
Water: H2O
The QCDPhase Diagram:
structure of matter with quark-
and gluon-degrees (color
degrees) of freedom.
Study QCD Phase Structure
- Signals for onset of sQGP
- Signals for phase boundary
- Signals for critical point
Observables:
1st order phase transition
(1) Azimuthally HBT
(2) Directed flow v1
Partonic vs. hadronic dof
(3) RAA: N.M.F.
(4) Dynamical correlations
(5) v2 - NCQ scaling
Critical point, correl. length
(6) Fluctuations
(7) Di-lepton production
- http://drupal.star.bnl.gov/STAR/starnotes
/public/sn0493; arXiv:1007.2613
BES-I: √sNN = 7.7, 11.5, 19.6, 27, 39GeV
Cleymans, Redlich
Chemical Freeze-out: (GCE)
- Central collisions => higher values of
Tch and μB!
- The effect is stronger at lower energy.
B. Schaefer et al., Phys. Rev. D75, (2007) 085015
(1) Lattice QCD calculations predict a first order phase transition seen, as a discontinuity in the density
(2) Slope of v1: manifestation of early pressure in the system
(3) Soft point?
Suppression of high pT hadrons is one of the key signatures for the formation of strongly interaction Quark-Gluon Plasma in high-energy nuclear collisions
The suppression was not observed in low energy Au+Au collisions, especially for √sNN ≤ 11.5GeV
The separation between the same-charge and opposite-charge correlations.
- Strong external EM field
- De-confinement and Chiral
symmetry restoration
AAA AA
- STAR: PR103, 251601; PRC81, 054908(2009)
STAR Preliminary
SS - OS
Below √sNN= 11.5 GeV, the splitting between the same- and opposite-sign charge pairs (SS-OS) disappear
If QGP is the source for the observed splitting at high-energy nuclear collisions hadronic interactions become dominant at √sNN ≤ 11.5 GeV
STAR: Phys. Rev. Lett. 110 (2013) 142301
Number of constituent quark (NCQ) scaling in v2 => partonic collectivity => deconfinement in high-energy nuclear collisions
At √sNN< 11.5 GeV, the v2 NCQ scaling is broken indicating hadronic interactions become dominant.
(1) Parton energy loss
(2) “Local Parity Violation”
(3) Partonic collectivity
STAR Preliminary
sQGP key signatures
turned off at √sNN < 11.5 GeV!
1) High moments for conserved quantum numbers: Q, S, B, in high-energy nuclear collisions
2) Sensitive to critical point (ξ correlation length):
3) Direct comparison with Lattice results:
Extract susceptibilities and freeze-out temperature. An independent/important test on thermal equilibrium in heavy ion collisions.
References:
- A. Bazavov et al. 1208.1220 (NLOTE) // STAR:PRL105, 22303(2010) // M. Stephanov: PRL102, 032301(2009) // R.V. Gavai and S. Gupta, PLB696, 459(2011) // S. Gupta, et al., Science, 332, 1525(2011) // F. Karsch et al, PLB695, 136(2011) // S.Ejirietal, PLB633, 275(06) // M. Cheng et al, PRD79, 074505(2009) // Y. Hatta, et al, PRL91, 102003(2003)
BES-II
RHIC
BES-I
STAR net-proton results:
All data show deviations below Poisson beyond statistical and systematic errors in the 0-5% most central collisions for κσ2 and Sσ at all energies. Larger deviation at √sNN ~ 20GeV.
UrQMD model show monotonic behavior in the moment products.
Higher statistics needed for collisions at √sNN< 20 GeV.
- STAR: X.F. Luo, QM2012
STAR Preliminary
RHIC BES-I Results:
- Partonic QGP dominant: √sNN >39GeV
Hadronic interactions become dominant: √sNN ≤11.5GeV
BES-II:
- High statistics data for energy region √sNN ≤ 20GeV.
The e-cooling at RHIC has started.
RHIC:Unique opportunities for exploring
QCD phase structure
Exploring the QCD Phase Structure
TE
RHIC, SPS
2
Large μB
FAIR, CSR
Tini, TC
LHC, RHIC
3
1
LHC+RHIC
sQGP properties
√sNN ~ 0.1 - 5 TeV
Future eRHIC
Cold nuclear matter properties
e + ion collisions
1
2
3
Partonic Matter
Hadronic
Matter
RHIC BES-II
QCD phase structure and critical point
√sNN ≤ 20 GeV
Emergent properties of QCD matter
- HF-II: B, ΛC
- Jet, gamma
CNM, spin
- QCD phase structure
- Critical Point
- CNM, CGC
- Phase structure with glue
HF, (e,μ)
BESII
HF’, pA
HFT/MTD
eSTAR
e-Cooling, iTPC
HFT’, Tracking, EM/HCAL (West side)
EMCAL (East side)
physics
upgrade
TE
RHIC, SPS
2
Large μB
FAIR, CSR
Tini, TC
LHC, RHIC
3
1
CEE 兰州重离子加速器
低温高密核物质测量谱仪
低温、高重子密度
强子相互作用
手征对称自发破缺
对称能Esym()
1
2
3
早期宇宙
发展演化
Partonic Matter
Hadronic
Matter
Quarkyonic matter?
部分子物质
(QGP)
强关联的核物质
重子化学势
强子物质
CEE – CSR-External-Target-Facility Experiment
SFC: 10 AMeV (H.I.), 17~35 MeV (p)
SSC: 100 AMeV (H.I.), 110 MeV (p)
CSRm: 1000 AMeV (H.I.), 2.8 GeV (p)
SSC
SFC
CSRe
RIBLL2
RIBLL1
CSRm
RIBLL1: 几十AMeV RIBs
RIBLL2: 百AMeVRIBs
CSRm: 冷却储存环
HIRFL-CSR 重离子加速器
外靶实验
装置(CEE)
二极磁铁
飞行时间探测器
多丝漂移室
靶
零度角量能器
重离子束
T0探测器
时间投影室
低温高密核物质测量谱仪(CEE)
利用当前最新技术在中国大型重离子加速器HIRFL-CSR(HIAF)上建设性能先进的多功能中高能重离子物理实验谱仪:
-三年完成基本实验设备建设
-高重子密度下的QCD相结构, 对称能高密行为, …
2)在中高能核物理领域建立一支由高校-中科院研究所密切结合的优秀科研团队
3)为国家中长期高能核物理规划, 核探测技术发展及其应用做贡献
哈尔宾工业大学,华中师范大学,山东大学,清华大学,中国科学技术大学,
中国科学院近代物理所,中国科学院上海应用物理所