Conjectured Phase Diagram

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Acoustic scaling of anisotropic flow in shape- engineered events: implications for extraction B ,T) of the QGP Roy A. Lacey Stony Brook University 1 Roy A. Lacey, Stony Brook University, April 24th, 2014

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Acoustic scaling of anisotropic flow in shape-engineered events : implications for extraction ( μ B ,T) of the QGP Roy A. Lacey Stony Brook University. p. A Current Focus of our Field. Quantitative study of the QCD phase diagram. Conjectured Phase Diagram. Interest - PowerPoint PPT Presentation

Transcript of Conjectured Phase Diagram

Page 1: Conjectured  Phase Diagram

Acoustic scaling of anisotropic flow in shape-engineered events: implications for extraction (μB,T) of the QGP

Roy A. LaceyStony Brook University

1 Roy A. Lacey, Stony Brook University, April 24th, 2014

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p

Conjectured Phase Diagram

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Quantitative study of the QCD phase diagram

Roy A. Lacey, Stony Brook University, April 24th, 2014

Interest

Location of the critical End point (CEP)

Location of phase coexistence lines

Properties of each phaseAll are fundamental to the phase

diagram of any substanceSpectacular achievement:Validation of the crossover transition leading to the QGP Necessary for the CEP?

A Current Focus of our Field

Extraction of the ()-dependence of transport coefficients is central to the heavy ion programs at RHIC and the LHC

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LHC access to high T and small RHIC access to different systems anda broad domain of the (,T)-plane

Exploit system size and beam energy lever arm

Roy A. Lacey, Stony Brook University, April 24th, 2014

Energy scan

Current Strategy

LHC + BES access to an even broader domain of the (,T)-plane

(,T) at freeze-out

RHICBES to LHC 360 increase

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4 Roy A. Lacey, Stony Brook University, April 24th, 2014

Essential Questions

At the CEP or close to it, anomalies inthe dynamic properties of the medium can drive abrupt changes in transport

coe cientsffi

Lacey et. al, Phys.Rev.Lett.98:092301 (2007)

()-dependence of transport coefficients , , etc? The role of system size and fluctuations? Location of phase boundaries? Indications for a Critical EndPoint (CEP)?

Anisotropic flow is an invaluable probe

Lacey et. al, arXiv:0708.3512 (2008)

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(η/s)RHIC estimates – QM2009 Excellent Convergence on the magnitude of η/s at RHIC

Roy A. Lacey, Stony Brook University, April 24th, 2014

4πη/s ~ 1 - 2

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Reminder

Status QuoA major uncertainty in theextraction of η/s stems from Incomplete knowledge of the Initial-state eccentricity model

εn – η/s interplay?

T dependence of η/s? μB dependence of η/s? Possible signal for CEP?

Subsequently

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Song et al

6Roy A. Lacey, Stony Brook University, April 24th, 2014

Status Quo

Status QuoA major uncertainty in theextraction of η/s stems from Incomplete knowledge of the Initial eccentricity?

εn – η/s interplay?

New methodology and constraints required

Luzum et al. arXiv 0804.4015

15-20%ε2 difference

2x η/s difference

η/s is a property of the medium and should not

depend on initial geometry!This is NOT an uncertainty; It is a failure of the method of

extraction

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7Roy A. Lacey, Stony Brook University, April 24th, 2014

Improved Methodology

Higher harmonics provide important constraints!

4πη/s for LHC plasma ~ 2

arXiv:1301.5893Bjoern Schenke et. al.

Can we find methodologies and constraintswhich are insensitive to the initial-state geometry?

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Roy A. Lacey, Stony Brook University, April 24th, 20148

The acoustic nature of flow leads to specific scaling patterns which :

I. Give profound mechanistic insight on viscous damping

II. Provide constraints for

initial state geometry and its fluctuations Extraction of the specific viscosity

(,T) dependence of the viscous coefficients Hints for a possible critical point?

Essential message

Significant and important recent development in the field!

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s/

P ² Bj

, , /s, f, Ts fc

20

3

1 1

~ 5 45

TBj

dER dyGeVfm

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Idealized Geometry

2 2

2 2

y x

y x

Crucial parametersActual collision profiles are not smooth,

due to fluctuations!Initial Geometry characterized by many

shape harmonics (εn) drive vn

Initial eccentricity (and its attendant fluctuations) εn drive momentum anisotropy vn with specific viscous modulation

22, exp 03

tT t k k Ts T

Acoustic viscous modulation of vn

Staig & Shuryak arXiv:1008.3139

Isotropic p

Anisotropic p

Yield(f) =2 v2 cos[2(fY2]

The Flow Probe

1

1 2 cosn nn

dN v nd

ff

Y

Roy A. Lacey, Stony Brook University, April 24th, 2014

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n nv

22, exp 03

tT t k k Ts T

Acoustic viscous modulation of vn

Staig & Shuryak arXiv:1008.3139

/k n R

Scaling expectations:

2( ) expn T

n

v p n

2

2 2

( ) exp ( 4)( )n T n

T

v p nv p

ln n

n

vR

vn is related to v2 System size dependencen2 dependence

Each of these scaling expectations can been validatedη/s , ’

Initial Geometry characterized by many shape harmonics (εn) drive vn

Scaling properties of flow

Roy A. Lacey, Stony Brook University, April 24th, 2014

t R

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Demonstration of acoustic scaling

What do we learn from these scaling patterns?

Roy A. Lacey, Stony Brook University, April 24th, 2014

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A B

Geometric fluctuations included Geometric quantities constrained by multiplicity density.

*cosn nn f

Phys. Rev. C 81, 061901(R) (2010)

arXiv:1203.3605

σx & σy RMS widths of density distribution

Geometric quantities for scalingGeometry

Roy A. Lacey, Stony Brook University, April 24th, 2014

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Relationship between initial and freeze-out geometry

Roy A. Lacey, Stony Brook University, April 24th, 2014

exquisitely demonstrated via HBT measurement

t R

Femtoscopic measurements

R and mT scaling of the full set of HBT data Similar expansion dynamics Larger expansion rates at the LHC

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exquisitely demonstrated via HBT measurement for several systems

t R

R (fm)1 2

Rin

v (fm

)

0

4

8

12

16Pb+Pb 2.76 TeVp+Pb 5.02 TeV

0.2 <kT<0.3 GeV/c

R (fm)0.0 0.5 1.0 1.5 2.0 2.5

Rsi

de (f

m)

0

2

4

6

82.76 TeV Pb+Pb - ALICE200 GeV Au+Au - PHENIX200 GeV Au+Au - STAR200 GeV d+Au - PHENIX

kT~ 0.4 GeV/c

(a) (b)

ALICE

Femtoscopic measurements arXiv:1404.5291

Relationship between initial and freeze-out geometry

Larger expansion rate at the LHC

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Npart

0 100 200 300 400v 2

0.10

0.15

0.20

0.25pT = 2-3 GeV/c

ATLAS Pb+Pb @ 2.76 TeV

Centrality 5-70%

ln n

n

vR

Characteristic scaling prediction is non-trivial

Eccentricity change alone is not sufficientTo account for the Npart dependence of vn

Transverse size ( ) influences viscous damping

Acoustic Scaling –

Scaling properties of flow

Roy A. Lacey, Stony Brook University, April 24th, 2014

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ln n

n

vR

Acoustic Scaling –

Characteristic viscous damping validated at RHIC & the LHC A further constraint for η/s

Scaling properties of flow

Roy A. Lacey, Stony Brook University, April 24th, 2014

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ln n

n

vR

Characteristic a

The relative magnitude of vn provides an important constraint!

Scaling properties of flow

Roy A. Lacey, Stony Brook University, April 24th, 2014

η/s Viscous hydrodynamics can be used for calibration

- Viscous Hydrodynamics

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Shape-engineered events

Roy A. Lacey, Stony Brook University, April 24th, 2014

Note characteristic anti-correlation predicted for v3(q2) in mid-central events

Shape fluctuations lead toa distribution of the Q vector

at a fixed centrality

Cuts on qn should change the magnitudes , , at a given centrality due to fluctuations

These magnitudes can influence scaling

Crucial constraint for initial-geometry models

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Shape-engineered events

Cuts on qn should change the magnitudes , , at a given centrality due to fluctuations

Roy A. Lacey, Stony Brook University, April 24th, 2014

ALICE data

q2(Lo)

q2(Hi)

Viable models for initial-state fluctuations should still scale

Shape fluctuations lead toa distribution of the Q vector

at a fixed centrality

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Acoustic Scaling of shape-engineered events

Scaling properties of flow

Roy A. Lacey, Stony Brook University, April 24th, 2014

Characteristic viscous damping validated for different event shapes at the same centrality A further constraint for initial fluctuations model and η/s

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Song et al

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Characteristic viscous damping validated in viscous hydrodynamics; calibration 4πη/s ~

Extracted η/s value insensitive to initial conditions

η/s show 100% uncertainty due to “uncertainty” about the initial geometry

η/s is a property of the medium and should not depend on initial geometryThis is NOT an uncertainty; It is an incorrect method of extraction

Extraction of η/s ln n

n

vR

Slope sensitive to 4η/s

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n2 scaling validated in experiment and viscous hydrodynamics;

calibration 4πη/s ~ 2Note agreement with Schenke et al.

2( )expn T

n

v pn

n20 10 20 30 40

ln(v

n/ n)

-6

-5

-4

-3

-2

-1

0

1

012.5

s0 1 2 3

0.050

0.075

0.100

0.125

0.1504s

n20 10 20 30 40

Data

(a) (b) (c)Pb+Pb @ 2.76 TeV

0.1%

Viscous Hydro

arXiv:1301.0165 & CMS PAS HIN-12-011

Slope sensitive to η/s

Extraction of η/s

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Anisotropy Measurements

An extensive set of measurements now span a broad range of beam energies ().

STAR - Phys.Rev.C86, 014904 (2012); Phys.Rev.C86, 054908 (2012) CMS - Phys.Rev.C87, 014902 (2013)

arXiv:1305.3341

Roy A. Lacey, Stony Brook University, April 24th, 2014

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ln n

n

vR

Characteristic viscous damping validated across beam energies

First experimental indication for η/s variation in the -plane

7.7 GeV 19.6 GeV 39 GeV 62.4 GeV 200 GeV

2.76 TeV

Acoustic Scaling –

Scaling properties of flow

Roy A. Lacey, Stony Brook University, April 24th, 2014

HBT should show complimentary

signals for similar

Lacey et. al. Phys. Rev. Lett. 112, 082302

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Flow is acoustic – “as it should be” Obeys the dispersion relation for sound propagation

(n2 & ) constraints for 4πη/s & viable initial-state models

4πη/s for RHIC plasma ~ 1 ~ my 2006 estimate4πη/s for LHC plasma ~ 2Extraction insensitive to initial geometry model

Characteristic dependence of viscous coefficient β” on beam energy give constraints for:

()-dependence η/s Indication for CEP??

Scaling properties of anisotropic flow lend profound mechanistic insights, as well as new constraints for

transport coefficients

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What do we learn?

Summary

Roy A. Lacey, Stony Brook University, April 24th, 2014

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End

26Roy A. Lacey, Stony Brook University, April 24th, 2014