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1
Introduction to relativistic heavy ion collisions
Zhangbu Xu 许长补 (BNL)
Quantum Chromodynamics
Theory of color
High-energy nuclear experiments
Practice of color
教材 相对论重离子碰撞物理导论 --- 黄卓然
Introduction to High-Energy Heavy-ion Collisions --- Cheuk-Yin Wong (Oak Ridge) STAR and PHENIX Beam Use Requests (run10 BUR) and presentations
to BNL Nuclear and Particle Program Advisory Committee (PAC) in 2009 RHIC whitepapers summarized first three-years’ discoveries:
Experimental and Theoretical Challenges in the Search for the Quark Gluon Plasma: The STAR Collaboration's Critical Assessment of the Evidence from RHIC CollisionsNucl. Phys. A 757 (2005) 102; e-Print Archives (nucl-ex/0501009)
Formation of dense partonic matter in relativistic nucleus-nucleus collisions at RHIC: Experimental evaluation by the PHENIX collaboration. Nucl.Phys.A757:184-283,2005; e-Print: nucl-ex/0410003
Quark gluon plasma and color glass condensate at RHIC? The Perspective from the BRAHMS experiment.Nucl.Phys.A757:1-27,2005. e-Print: nucl-ex/0410020
The PHOBOS perspective on discoveries at RHIC.Nucl.Phys.A757:28-101,2005. e-Print: nucl-ex/0410022
LHC: ALICE, ATLAS, CMS Heavy Ion Collisions at the LHC - Last Call for Predictions.
J.Phys.G35:054001,2008. e-Print: arXiv:0711.0974 [hep-ph] ALICE: Physics performance report, volume I, II.
J.Phys.G30:1517-1763,2004; J.Phys.G32:1295-2040,2006
International Conferences of Quark Matter (proceedings, talks)
2办公室 : 306 ( 陈宏芳教授);唐泽波:410
3
Outline of the lecture series1. Introduction2. Jet Quenching3. Initial Conditions 4. Hydrodynamics and
Thermalization5. Heavy Flavor 6. Color-Screening 7. Dilepton 8. Proton Spin9. RHIC Machine Complex10. Search for Exotic Particles
and phenomena 11. Correlation and fluctuations:
search for critical behavior
Detector, and R&D Detector overview Time Projection Chamber Time-of-Flight Heavy Flavor Tracker
STAR Upgrades Future frontiers
Schedule
4
09/07,09/10 09/14, 09/17 09/21,09/24 09/28
6 Introduction IRHIC movies
Initial Conditions Geometry II
Dr. Zebo Tang lectures: TOF
Heavy Flavor physics
7 Introduction IIHomework
HomeworkFlow and thermal models I
Concept of Time-of-Flight: scintillator, MRPC
Color Screening Ilow-pT effect
8 Discussions Q&A on homework
Flow and thermal models IIHomework
TOF Calibration and Performance
Color Screening II
high-pT effect
6 LHC MoviesJet Quenching I
Non-equilibrium and non-extensive statistics
Physics and Applications
7 Jet Quenching IIHomework
HomeworkSTAR Detector I
R&D (MTD, FAIR, BESIII)
8 Initial Conditions Geometry I
STAR Detector IIHomework
Homework
Schedule
5
10/12,10/15 10/19, 10/22 10/26,10/29 11/02
6 Proton Spin I Exotic particle Searches I Scientific debates on Physics cases
Final work on a recommendation for BUR
7 Proton Spin II Exotic Particle Searches II STAR vs PHENIX Beam Use Requests for run 10
Future Frontiers I
8 Homework Homework, Q&A Students present their cases (main physics cases)
Future Frontiers II
6 Detector Upgrades I Correlation and Fluctuation I (searching for onset)
Form groups to simulate the PAC review
7 Detector Upgrades II Correlation and Fluctuation II (searching for onset)
Scientific debates
8 Homework Homework, Q&A Homework
6
Outline
Introduction to theory of color (strong force)
Selected experimental studies of strongly interacting color medium – Perfect Liquid Introduce terms and methods
Exploring the properties with flavor and color via identified particles Color charge
Future prospects -- Detector upgrades necessary
7
Strong force – one of the four in nature
1.Gravity Makes apple fall to ground
2.(3.) Electromagnetic+weak (2 unified forces) Bonds atoms together; Makes apple red and tasty
4. Strong forceGenerates 98% of apple’s mass
8
Structure of an atom
1.Where is the strong force most relevant? Atomnucleusproton/neutronquarks/gluons
electron
nucleus
nucleons
proton
neutron
gluons quarks
10-10m 10-14m 10-15m (1fm) <10-19m
9
Theory of strong force
Quantum Chromodynamics charge: color (r,b,g) 3 constituents: quarkmediator: gluon
Quark: ONE color chargeGluon: TWO color charges
Ordinary hadrons are color neutral particles-- Mesons: 2 quarks (r+rbar)Baryons: 3 quarks (r+b+g)
Three quarks for Muster Mark!James Joyce. Finnegan's Wake
Electromagnetic force 1 lepton, quark, etc photon
photon: no charge
10
Asymptotic Freedom and Origin of Mass
Peculiar theory of color -- weak at large momentum
and short distance Confined 禁锢– required
energy grows with distance no FREE quark or gluon,
fragment to “jet”– cluster of color-neutral particles
Generate most of the mass of visible world (m=E/c2)
F. Wilczek, H.D. Politzer, and D.J. Gross, 1973; Nobel Prize 2004
jet
proton
neutron pion
Anti-quark
prot
on
neut
ronpion
quar
k
LEP at CERN
渐进自由和质量产生
喷注
11
Free the quarks and gluons
… our vacuum, though Lorentz invariant, to be quite complicated. Like any other physical medium, it can carry long-range-order parameters and it may also undergo phase transitions…
The experimental method to alter the properties of the vacuum may be called vacuum engineering. An effective way may well be to use relativistic heavy ions.
T.D. Lee 19741957 Nobel Prize winner
Quark-Gluon Plasma (Liquid)
Ene
rgy
Den
sity
/T4
加热真空达到相变的工程
( 释放夸克和胶子 )
12
Little Big Bang
RHIC
TIME
13
Units and dimensions
Temperature: 160MeV (trillion 0C)System size: 10fm (10-12cm) Lifetime: 10fm/c (10-22s)Particles#: thousandsAu: 79 protons + 118 neutronsNumber of Participant nucleons
Temperature Momentum Energy Mass
MeV 10billion 0C 5x10-28kg m/s c 2x10-13J 2x10-30kgc2
MeV = 1 million electron volt; GeV = 1 billion electron volt
Size of a proton: 1fmProton mass: 1 GeV/c2
Time: 1fm/c
14
In the rest of my talk
Introduction to theory of color (strong force)
Selected experimental studies of strongly interacting color medium – Perfect Liquid Introduce terms and methods
Exploring the properties with flavor and color via identified particles Color charge
Future prospects -- Detector upgrades necessary (RHIC II)
15
Four Detectors1200 Physicists 120 PhD theses Publications: topcite 50+ (72), 100+ (38), 250+ (9) CDF+D0 9
LEP 15
16
Event in real detectors
e+e-: tens of tracks, jet structure A+A: thousands of tracks, isotropic,
4m
17
(a) (b)
(d)(c)
(a) (b)
(d)(c)
中心对撞
偏心对撞
质心能量 =9.2 GeV
18
Color Glass CondensateModels prior to RHIC
Initial condition: high density gluonsDIS: ep, eA (eRHIC)
Physics Today, Ludlam/McLerran
CGC: high density gluons Dilute gas
momentum
Simple Counting
19
Study phase transition, 101
Count particles Energy System size
Phase boundary: 1 GeV/fm3
Normal nuclear density0.16GeV/fm3
1.Equilibration time 2.TemperatureWhat we need to know then are:
Energy Density and Temperature
Ene
rgy
Den
sity
/T4
20
Temperature from Chemistry among hadrons
Statistical Mechanics describes the relative particle abundances
This happens at the phase boundary (T=165+-10MeV)
STAR whitepaper
强子的热统分布 : 温度和化学势
21
Critical Temperature is not ONE number
22
QCD Phase Diagram
Baryon Density
23
Sensitive to equilibration time
Ideal hydrodynamics describes the anisotropic flow
Liquid-like matter
Strong coupling; Surprisingly Fast equilibrium(<<1fm); low viscosity 粘度 (shear 剪切 , bulk 体积 ) important theoretical implication
RHIC animations and multimedia: http://www.phenix.bnl.gov/WWW/software/luxor/ani/
24
Jet Quenching 喷注淬灭 Another probe of early stage Energetic quarks/gluons
traverse QGP, they radiate soft gluons and lose energy
Reduce the abundance of high momentum particles and their correlations
25
Experimental and Theoretical Challenges in the Search for the Quark Gluon PlasmaThe STAR Collaboration’s Critical Assessment of the Evidence from RHIC Collisions, Nucl. Phys. A 757 (2005) 102
Strong evidences pointing to a “dense, opaque, low-viscous, pre-hadronic liquid state of matter not anticipated before RHIC”
Study the properties of thisthis matter.What are the critical needs from future Experiments (STAR White paper)?
26
Connections to other fields
H2O
Black Hole, String Theory universal low viscosity limit 1/4
Big Bang
•Low-temperature Atomic Physics
•EOS of Neutron stars
•Strong field condensed matter physics of QCD
Phys.Rev.Lett.94:111601,2005; Phys.Rev.Lett.97:152303,2006http://www.bnl.gov/rhic/blackHoles2.asp
27
In the rest of my talk
Introduction to theory of color (strong force)
Selected experimental studies of strongly interacting color medium – Perfect Liquid Introduce terms and methods
Exploring the properties with flavor and color via identified particles Color charge
Future prospects -- Detector upgrades necessary (RHIC II)
28
Color factor (gluon and quark)?
Quark: ONE color charge => pionGluon: TWO color charges => proton
Difference between gluon and quark jet quenching
Need good hadron identification at very high transverse momentum
29
Quark vs gluon from hadron suppression
X.N. Wang and X.F. Guo, NPA 696, 788 (2001)W. Liu, C.M. Ko, B.W. Zhang, nucl-th/0607047
STAR, L. Ruan
PRL 97, 152301 (2006)
Curves: X-N. Wang et al PRC70(2004) 031901
No sign of stronger gluon energy loss in p/ or p/p ratios
Need good understanding of how quarks and gluons turn into hadrons
pT (GeV/c)
STAR, B. Mohanty
强子压底
30
Is Color charge a factor?
QCD Models: gluon, light quark and heavy quark lose different amount of energy
Experimental results so far do notgpbar, u/d c e
Jet Quenching picture works
Something interesting happens
Strongly interacting (radiational+collisional)
Future investigations
31
In the rest of my talk
Introduction to theory of color (strong force)
Selected experimental studies of strongly interacting color medium – Perfect Liquid Introduce terms and methods
Exploring the properties with flavor and color via identified particles Color charge
Future prospects -- Detector upgrades necessary (RHIC II)
32
Upgrades for STAR experiments
Thermometers: dilepton, photon
Color Screen: heavy quarkonium species.
Near/Long Term: STAR white paper Nucl. Phys. A 757 (2005) 102
33
QCD Phase Diagram
1. Can we put a point above? Exp(-e/T)
2. Can we study the mass structure directly (chiral symmetry restoration)
3. Electron, Muon, photon, heavy quarks
4. Rare probes need high luminosity
强相互作用相图
34
Brownian motion of Heavy quarks
Charm quarks m ~ 1200 MeVT ~ 165 MeV
“drag” and diffusion of “solid” object
Direct Reconstruction Elliptic flow Spectra
c c
0DK
0D
K- +
重味夸克的布朗运动
测 QGP 阻力和扩散系数
35
Color Screening of heavy quarks
J / suppression J /+- (e+e-)
Different states predicted to melt at different T in color medium (Td/Tc)
Charmonia(J/), bottomonia ()
Coalescence of charm
Quarkonium dissociation temperatures – Digal, Karsch, Satz
Active program at PHENIX, STAR, SPS
重味夸克介子的色屏蔽 :QGP 温度和相关长度
36
STAR Upgrades
Muon Dete
ctor
Time Of Flight
37
Time Projection Chamber (TPC):
45 padrow, 4 meters (diameter)
Magnetic field: 0.5Tesla
Identify particles by TPC 时间投影室带电粒子的电离能损随动量变化
38
Time-of-Flight (TOF):
1 tray (~1/200, prototype), (t)=85ps
m2 = p2/(1/2-1), =l/t
Identify particles by TPC + TOF
39
STAR Time-of-Flight
Multi-gap Resistive Plate ChamberNew technology, Cost-effectiveHadron PID, electron PID
Project supported by DOE(US) & NSFC, MST,CAS(China)
Time-of-Flight Module 4000 of them
40
Novel & Compact Muon Detector for QCDLab Novel and Compact -------- Convention
Timing, Position Track Segments+FastHits
Muon is penetrating probe
QCDLab (RHIC II, eRHIC)
Works with Accelerator High Luminosity upgrades
A BNL 2007 LDRD project
41
Hadron Rejection and Muon Trigger at STAR
Iron bars
•Muon penetrates iron bars Other particles are stopped
•Good Time Resolution (60ps) rejects background (>100)
•1 hit per 5 head-on Au+Au
•Large coverage: diameter of 7 meters
42
A prototype in the making
Resolution: ~60ps (6x10-11second)Signal propagation velocity: ~60ps/cm Spatial resolution: ~1cm20x larger than the TOF modules
1meterx20cmInstall in next RHIC data taking
43
Conclusions (a colorful journey)
Perfect Liquid
Continue to explore its: Flavor, color, sound, temperature Viscosity, in-medium mass,
critical point, correlation length Multi-discipline:
string, condensed matter, DIS, atomic, astrophysics
Detector and accelerator upgrades necessary (RHIC II)
The Holy Grail is not in the finding. It is in the journey!Saul Zaentz, 1997
44
BACKUP
45
作业题 I
你认为 RHIC 主要经费支出 (~1.5 亿 / 年 ) 是什么 ?
1. 买黄金 (Au+Au collisions,1010 ions per 8 hours)
2. 付电费 (15 megawatts)
3. 付员工工资 (~400 科学家 , 工程师 , 技术工 )
4. 分给合作单位 (~100 institutions, ~20 countries)
5. 发展新项目 (Rearch&Development)
6. 捐献给慈善机构
46
作业题 II1 )一只蚊子以其正常飞行速度撞到静止的玻璃,
所损失的动能, 和 RHIC 200 GeV p+p collision 一个事例的总能量相比 ?
2 ) RHIC 200 GeV Au+Au collision 能量密度是水密度的几倍?
3) QCD 相变温度是太阳表面温度的几倍?
4) RHIC, LHC 能产生黑洞吗?