1 introduction to relativistic heavy ion collisions zhangbu xu 许长补 (bnl) quantum...

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




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






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






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？

1 introduction to relativistic heavy ion collisions zhangbu xu 许长补 (bnl) quantum...

Documents