Musings on Jet Medium Interaction Roy A. Lacey Chemistry Dept. Stony Brook University

Musings on Jet MediumInteraction

Roy A. LaceyChemistry Dept.

Stony Brook University

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1. Characteristics of the Medium2. Jet-medium interactions

Extraction of jet functions3. Summary of few things learned

“Any man who knows all the answers most likely misunderstood the questions”Nancy Willard

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Roy A. Lacey, Stony Brook University; CATHIE-RIKEN Workshop, BNL

Feb 25 - 26, 2009

Goldnucleus

Gold nucleus

v~0.99c

z:collision axis

t

0

t = z/

c

t = -z/c “Thermalized” partonic Fluid!(s)QGP?

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1 1 TBj

dE

R dy

eBjorken ~ 5 - 15 GeV/fm3

~ 35 – 100 ε0

A “little Bang” occurs in RHIC collisions

How do we probe the properties this fluid?

3

u

Extraction of transport coefficients (η/s, q, cs, λ, etc) can lend decisive insight

Accurate measurements are crucial!

Correlation measuremen

ts

Flow Correlati

ons

Jet Correlatio

ns


Feb 25 - 26, 2009

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The case is now closed on issues of non-flow etc, via 5 separate measurements of v2 and v4 in the same experiment

The non-flow “chicken” has come home to roost

The non-flow “chicken” has come home to roost

New RXNdetector

3.1 3.9BBC

3.1 3.9MPC

1.5 2.8iRXN

1.0 1.5RXNo

1.0 2.8ioRXN

Event planes

PHENIX Preliminary


Feb 25 - 26, 2009

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Kinetic Energy DensityP KET – CQN ScalingKET – CQN Scaling

Phys. Rev. Lett. 98, 162301 (2007)

Mesons

Baryons

Quark-Like Degrees of Freedom EvidentIndication of strong coupling?


Feb 25 - 26, 2009

~

~

~dbr

vl

s nm

mvls

Arguments which say that quark degreesof freedom can not be

present are silly!

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KET & nq2 scaling validated for

v4

KET and CQN Scaling for v4KET and CQN Scaling for v4

PHENIXPreliminary


Feb 25 - 26, 2009

Further Indication of strong coupling?

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2

1

) (pv

) (pv

T2

q2,

Tq4,

4,q T4,M

2 22,M T 2,q T

4,q T4,B

2 22,B T 2,q T

v (p )v (2p ) 1 1( )

v (2p ) 4 2 v (p )

v (p )v (3p ) 1 1( )

v (3p ) 3 3 v (p )

T

T

a

a

Hints?1. Hadronization?2. Partonic Thermalization?

Is this an indication that the partonic fluid is thermalized?

Is this an indication that the partonic fluid is thermalized?

aRelated to η/s ?


Feb 25 - 26, 2009

Vn is universal

Further Indication of

strong coupling?

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Npart

0 100 200 300

v 2/

0.1

1

0.5 < pT < 0.8 (GeV/c)0.8 < pT < 1.21.2 < pT < 1.61.6 < pT < 2.4

Npart

0100200300

v 2/

0.0

0.2

0.4

0.6

0.8

0.5<pT<0.8 (GeV/c)

0.8<pT<1.2

1.2<pT<1.6

1.6<pT<2.4

PHENIX Preliminary

42

v

Straightforward estimation of the degree of local equilibrium and η/s as a function of centrality!

10-15% larger than for fluid with η/s =1/4π in central events.

λ = 0.3 – 0.35

~npart

KN

12 2

1 10

khdk k nk k

n

v v K

K K

~ ( )s n sTc K RT cs

Better constrained estimates of coefficients

Better constrained estimates of coefficients

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x10

x20

4 1~ 0.1, 0.2, 0.5

3s sT T

QCD Sonic Boom

Same-Side Jet

High pT trigger

**

Gives sound speed directly; Sets upper limit on viscosity.

M

cos M sc

Medium Response & Transport Coefficients

Medium Response & Transport Coefficients


Feb 25 - 26, 2009

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2P & 3P correlation measurements? Strategy

Compare jet correlations in pp & AA Collisions

A B

B It is necessary to decompose flow and Jet correlations Jet function

ZYAM


Feb 25 - 26, 2009

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There are three methods to gaining wisdom.

The first is reflection, which is the highest. The second is limitation, which is the easiest. The third is experience, which is the bitterest.”

Confucius

Reflection• Based on a two source model

Two source models with similar Input same result.• Jets correlate [or/not] with event

plane• Flow contributions dominate• Accurate determination of v2

required• Jet function (shape) is insensitive

to ZYAM assumption

The “’wisdom” of ZYAM!

Limitations• Uncertainty in jet

yields


Feb 25 - 26, 2009

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Same-Side Jet

Away-Side Jet

*

High pT trigger

Assoc. pTs

*

(2+1) processes efficiently removed via two-event mixing to obtain true three particle correlations

Deflected jet Mach Cone

* *

* * Re* *

,3 ,

,al

Mix

NC

N

Validation test of the use of two event mixing to remove 2+1 processes


Feb 25 - 26, 2009

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Di-jet correlation measurements?

A B

BA

B


Feb 25 - 26, 2009

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Medium Response

Modified Away-side topology is pT independent


Feb 25 - 26, 2009

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Medium Response“Particle composition”

Composition of away-side jet similar to inclusive measurement


Feb 25 - 26, 2009

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Data

Simulated Deflected jet

Simulated Mach Cone

Data compatible with the presence of a Mach Cone away-side jet

Total 3PC jet correlations

True 3PC jet correlations

QCD Sonic Boom?QCD Sonic Boom?

1~ 0.35, ~ 2

4sc s


Feb 25 - 26, 2009

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simul

Jet Suppression

Simultaneous fits to IAA and RAA provide improved constraints


Feb 25 - 26, 2009

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A central goal of current relativistic heavy ion research is the extraction of the transport

properties of the recently discovered sQGP.

Correlation measurements provide important constraints for a number of these properties• Scattering power• Sound speed• Sound attenuation• viscosity• etc.

Summary


Feb 25 - 26, 2009

Documents

Musings on Jet Medium Interaction Roy A. Lacey Chemistry Dept. Stony Brook University