QCD in the Twenty-First Century

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Nu Xu 1/20 ATHIC2012“, Pusan, Korea, November 14 - 17, 2012 QCD in the Twenty-First Century (1)Higgs (-like) Particle - Origin of Mass, QCD dof - Standard Model The Theory (2) QCD Emerging Properties - Confinement, χ C symmetry - QCD Phase Structure - Nucleon helicity structure Emergent properties with QCD degrees of freedom!

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QCD in the Twenty-First Century. Emergent properties with QCD degrees of freedom! . Higgs (-like) Particle – - Origin of Mass , QCD dof - Standard Model  The Theory (2) QCD Emerging Properties – - Confinement, χ C symmetry - QCD Phase Structure - PowerPoint PPT Presentation

Transcript of QCD in the Twenty-First Century

Page 1: QCD in the Twenty-First Century

Nu Xu 1/20 ”ATHIC2012“, Pusan, Korea, November 14 - 17, 2012

QCD in the Twenty-First Century

(1) Higgs (-like) Particle – - Origin of Mass, QCD dof

- Standard Model The Theory

(2) QCD Emerging Properties –- Confinement, χC symmetry- QCD Phase Structure

- Nucleon helicity structure - … - Non-linear QCD at small-x - …

Emergent properties with QCD degrees of

freedom!

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Nu Xu 2/20 ”ATHIC2012“, Pusan, Korea, November 14 - 17, 2012

High-Energy Nuclear Collisionsand QCD Phase Structure

Nu Xu(1,2)

(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

Page 3: QCD in the Twenty-First Century

Nu Xu 3/20 ”ATHIC2012“, Pusan, Korea, November 14 - 17, 2012

2 TE RHIC, SPS, FAIR

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3 Phase boundaryRHIC, FAIR, NICA

Exploring the QCD Phase Structure

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LHC, RHIC

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QCD ThermodynamicsSB Ideal GasRHIC

LHC

1) At μB = 0: cross over transition, 150 < Tc < 200 MeV

2) The SB ideal gas limit: T/Tc ~ 107

3) Tini (LHC) ~ 2-3*Tini (RHIC)

4) Thermodynamic evolutions are similar for RHIC and LHC

Zoltan Fodor, Lattice 2007

Page 5: QCD in the Twenty-First Century

Nu Xu 5/20 ”ATHIC2012“, Pusan, Korea, November 14 - 17, 2012

Jets at SPS, RHIC and LHC

1) Stronger suppression at higher collision energies 2) RAA ~ 0.5 for charged hadrons at high pT (~100 GeV/c)

in central Pb+Pb central collisions

Nuclear modification factor:

R AA =dNAA /dp T

⟨TAA⟩dσ pp /dp T

⟨TAA⟩=⟨ncoll ⟩σ inel

NN

RCP =dNAA /dp T /ncoll centdNAA /dp T /ncoll per

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Nu Xu 6/20 ”ATHIC2012“, Pusan, Korea, November 14 - 17, 2012

Medium Effects:Quarkonia

key words: thermometer, deconfinement, Debye screen, regeneration (coalescence)

Page 7: QCD in the Twenty-First Century

Nu Xu 7/20 ”ATHIC2012“, Pusan, Korea, November 14 - 17, 2012

J/ψ Suppression or Enhancement

mid-rapidity forward-rapidity

1) Due to large charm production cross section at LHC and coalescence process, the J/ψ RAA increased in mid-rapidity at central collisions. More such increase is expected in √sNN = 5.5 TeV Pb+Pb collisions.

2) Both suppression: “Debye Screening” and the recent observed increase: “Coalescence”, demonstrating the sQGP medium effect.

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Model Comparisonsmid-rapidity forward-rapidity

1) Models predict yield RAA well.2) To indentify the production

mechanism and study the properties of the medium: shadowing, collectivity, coalescence, etc, study:

More see Pengfei’s talk.

R AA(pT2 ) = pT

2 AA/ pT

2 pp

Page 9: QCD in the Twenty-First Century

Upsilon Productions

1) Temperature measurement?2) Systematic study transverse momentum

dependence of quarkonia productions in high-energy nuclear collisions:

R AA(N) = NAA / N pp

RAA(pT) =N(pT)AA /N(pT)

pp

RAA(pT2 ) = pT

2 AA/ pT

2 pp

Page 10: QCD in the Twenty-First Century

Nu Xu 10/20 ”ATHIC2012“, Pusan, Korea, November 14 - 17, 2012

Medium Effects:Collectivity

key words: partonic collectivity, thermalization, perfect liquid

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1) Collectivity increase as collision energy

2) √sNN > 39 GeV, partonic dominant √sNN ≤ 11 GeV, hadronic dominant

STAR data: arXiv:1206.5528ALICE data: Phys. Rev. Lett. 105, 252302 (2010)

Collectivity vs. Collision Energy

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Nu Xu 12/20 ”ATHIC2012“, Pusan, Korea, November 14 - 17, 2012

Collectivity ~ Collision EnergyALICE: PRL105, 252302(10); arXiv:1208.1974STAR: PRC66, 034904(02); PRC72, 014904(05); PHENIX: PRL98, 162301(07); PHOBOS: PRL98, 242302 (07) CERES: NPA698, 253c(02); E877: NPA638, 3c(98); E895: PRL83, 1295(99).

STAR Preliminary

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Nu Xu 13/20 ”ATHIC2012“, Pusan, Korea, November 14 - 17, 2012

Di-electrons: √sNN Dependence

1) Di-lepton: penetrating-bulk probe2) LMR: no significant energy dependence in enhancement3) Future: focus in 1 < mll < 3 GeV/c2, to

- Measure correlated charm contributions- Extract direct radiation information

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Nu Xu 14/20 ”ATHIC2012“, Pusan, Korea, November 14 - 17, 2012

Light hadron collectivity: partonic + hadronic

(s, c) hadron collectivity: partonic!

Di-leptons (m > 1 GeV) collectivity: 1) partonic2) direct radiation

√sNN = 200 GeV Au + Au Collisions

Future: Partonic Collectivity, Direct Radiation

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Nu Xu 15/20 ”ATHIC2012“, Pusan, Korea, November 14 - 17, 2012

sQGP and QCD Phase Structure

sQGP formed at μB ~ 0: - Collectivity: NCQ scaling in v2, … - Jet-quenching, Quarkonia, γ, …

RHIC BES-I Program: - Partonic dominant: √sNN > 39 GeV (μB ≤ 100 MeV) - Hadronic dominant: √sNN ≤ 11.5 GeV (μB ≥ 300 MeV)

What is the structure of the QCD phase diagram? - phase boundary? - QCD critical point?

Observations:(1) Azimuthally HBT 1st order phase transition

(2) Directed flow v1

1st order phase transition

(3) Dynamical correlations partonic vs. hadronic dof

(4) v2 - NCQ scaling partonic vs. hadronic dof

(5) Fluctuations Critical point, correl. length

- http://drupal.star.bnl.gov/STAR/starnotes/public/sn0493- arXiv:1007.2613

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Medium Effects:Critical Point

key words: QGP phase, hadronic phase, 1st order phase boundary, critical end point, correlation length, critical

slowing down...

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Nu Xu 17/20 ”ATHIC2012“, Pusan, Korea, November 14 - 17, 2012

Higher Moments

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:

4) Extract susceptibilities and freeze-out temperature. An independent/important test on thermal equilibrium in heavy ion collisions.

- A. Bazavov et al. 1208.1220 (NLOTE)- STAR Experiment: 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)- M.Cheng et al, PRD79, 074505(2009)- Y. Hatta, et al, PRL91, 102003(2003)

dN( )2 ≈ ξ 2, δN( )

3 ≈ ξ 4.5, δN( )4 ≈ ξ 7

S *σ ≈ χ B3

χ B2 , κ *σ 2 ≈ χ B

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χ B2

M. Cheng et al, PRD79, 074505(2009)

R. Gavai and S. Gupta, QM2012

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Higher Moment: Net-charge

STAR Preliminary

- PHENIX: E. O’Brien, QM2012- STAR: D. McDonald, QM2012 - HRG Model: K. Redlich et al, private communications, 2011

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STAR net-proton results: 1) 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.

2) UrQMD model show monotonic behavior

3) Higher statistics needed for collisions at √sNN < 20 GeV

Net-proton Higher Moments

STAR Preliminary

STAR: X.F. Luo, QM2012

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Summary and Outlook1) Heavy flavor:

(a) NMF for HF jets and hadrons extract transport properties and understand energy loss

mechanism (b) Collectivity of HF hadrons thermalization of the medium

2) Di-lepton: pT, v2, RAA, polarization temperature and collectivity of the partonic medium

3) RHIC BES-II/NICA/FAIR at √sNN < 20 GeV exploring QCD phase diagram, search for the possible critical point, quarkyonic matter

4) small-x (forward-y) physics exploring the structure of cold nuclear matter, dynamical evolution from the CNM to sQGP

LHC/RHIC provides unique opportunities for exploring matter with QCD degrees of freedom!

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2 TE RHIC, SPS

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3 Large μB

NICA, FAIR, CSR

研究 量子色动力学 (QCD) 相结构

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LHC+RHICsQGP properties

√sNN ~ few TeV

RHIC BES-IIQCD phase

structure and critical point √sNN ≤ 20 GeV

NICA/FAIRQCD phase structure

√sNN ≤ 12 GeV

Future eRHICCold nuclear

matter properties

e + ion collisions

Emergent properties of QCD matter

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