consistency of jet quenching predictions at the lhc

Ivan Vitev&

Consistency of Jet Quenching Predictions at the LHC

Ivan Vitev, T-16 and P-25, LANL

“High PT Physics at the LHC” workshop, March 23-27, Jyvaskyla, Finland

[ “The hot, the heavy and the cold” ]

Ivan Vitev&

2

Outline of the Talk

The problem of predictions versus fits for QGP suppression

• Consistency between hard and soft observables • Entropy density, energy-momentum conservation, … • Examples from RHIC and LHC

The problem of applicability of the jet-quenching approaches

• Light hadrons versus heavy quarks – the issue of formation time • New approach to D- and B-mesons suppression in the QGP• Results for the LHC

The problem of completeness in jet quenching phenomenology

• Inclusion of cold nuclear matter effects• Understanding initial- versus final-state radiative energy loss • Example at the LHC

Conclusions

Ivan Vitev&

3

• Can you live without 11 dimensions in the QGP?

Part I [ The Hot ]

Ivan Vitev&

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Few Real Predictions

dy

dN

dy

dN chg

2

3

--- Levai L/λ = 4

--- Wang dE/dx =0.25 GeV/fm

--- Vitev dNg/dy = 900

Saskia Mioduszewski, QM 2002

• Before the real high pT

data appeared

Entropy rapidity density:

QGP formation time:

• Afterwards – many fits from various models with parameter tuning

Require consistency

fm15.00

Ivan Vitev&

5

I.V., Phys.Lett.B 639 (2006)

Light Hadron Quenching in A+A (E-Loss)

(1) R s

3(1)

2

2g

g

2R s

2CE Log ... ,

4

Static medium

9 C 1E Log ... ,

4 A

(L)

dNdy (L

1+1D

)

L 2E

Bjo

L

2EL

L

rken

• Theoretical reason: the only wayto formulate energy loss without unphysical sensitivity to the formation time

400T MeV3

exp 0318 . 1( ) 00 0.14 .GeV fm GeV fm

2 10.35 0.8 .ˆ 5 GeVq fm Significantly different values areindicative a theoretical inconsistency

Ivan Vitev&

6

Scales in Thermalized QGP (GP)

3e

2exp

0

xp 0

1200

1( ) , 120

0

6

( ) 1

.

7

g

g

dN

dydN

A fmA dy

f

m

m

f

• Experimental: Bjorken expansion• Theoretical: Gluon dominated plasma2

/ 30

32

#( ) [

1 4#

1 (2 )

where # 2( ) 8( ), [3] 1.2

3]the Tory p

p dpDoF

e

DoF polarizati

D

on

oFT

colo

T

r

400T MeV

• Energy density4

( )30 [3]

( )theory theory T TT

3

exp 0318 . 1( ) 00 0.14 .GeV fm GeV fm

• Transport coefficients (not a good measure for expanding medium)2

, 2 2.5 ( 0.3 0.5)4sD

gggT

0.8 1D GeV 2

2

9 1

2,gg s

Dg gg

2 29ˆ

2D

g

sq

11 5 .ˆ 2. Gq eV fm

0.75 0.42g fm

• Define the average for Bjorken0

20

2ˆ( )ˆ

( )

L

zq z zdzq

L z

2 10.35 0.8 .ˆ 5 GeVq fm

3

2

chg d

d d

dN

y y

dN

d

Ivan Vitev&

7

Energy momentumviolation

The Cause of the Inconsistency

2200 GeVˆ 14 GeV /fmq

25500 GeVˆ 100 GeV /fmq

2/ˆ 2Lqc Typical gluon energy

( 5 )c L fm

• Note that the region of PT at RHIC is 10-20 GeV and at the LHC 100-500 GeV

cR L

R

~10000~100000Difference

C.A.Salgado, U.Wiedeman, Phys.Rev.D (2003)

2200 GeVˆ 0.4 GeV /fmq ~500

GLV

A useful table

Realistic0 gNP e

Consistent, energy-momentum conservingcalculations should be used before one

looks at string theory for help

GeV875GeV6250

GeV25

Ivan Vitev&

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Ivan Vitev, LANL

Gluon Feedback to Single Inclusives

I.V., Phys. Lett. B 639 (2006)

• High pT suppression at the LHC can be comparable and smaller than at RHIC

• LHC quenching follows the steepness of the partonic spectra. There is a constant suppression region

• The redistribution of the lost energy is very important at the LHC. 100% correction and pT<15 GeV affected

Ivan Vitev&

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• Can you really quench heavy flavor?

Part II [ The Heavy ]

Ivan Vitev&

10

Heavy Quark Mass and Radiative Energy Loss

11

(1 ) (1 )

2

2 22

2 2

22

2

,g

n ngm x M

m

xE

k k k

x Mx

p Ek k

M.Djordjevic, M.Gyulassy, Nucl.Phys.A (2004)

2 s

1

sin * in *

gvac R sdN C

d d d

For massive quarks - "dead cone effect"

2 22 2sin

sin *

(sin * / )*

gvac R sdN C

d d d M E

Cuts part of phase space*

Ivan Vitev&

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S. Wicks et al., nucl-th/0512076

• Radiative Energy Loss using (D)GLV (both c + b)

• Radiative + Collisional + Geometry (both c + b) (overestimated)

• Deviation by a factor of two

• Is it accidental or is it symptomatic?

Non-Photonic Electron / Heavy Flavor Quenching

• Single electron measurements (presumably from heavy quarks) may be problematic for mainstream theory

Proceed to A+A collisions

Ivan Vitev&

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Conceptually Different Approach to D / B

• Fragmentation and dissociation of hadrons from heavy quarks inside the QGP

• Problem: treated in the same way as light quarks

D B

25 fm 1.6 fm 0.4 fmform ( 10 )Tp GeV

PartonHadron

p

zp

(1 )z p

~ QCDk

B

D

QGP extent

2

orm

2

f

2

(0.2 . ) 2 (1 )1

(1 ) (1 )

/(1 )Q

h q

GeV fm z zy

p k z z z

y

m M

p

2

, ,02

qq

Mp p

p

2 2

, ,2

hh

k mp zp k

zp

2

(1 ) , ,2(1 )g

kp z p k

z p

+

C.Y.Wong, Phys.Rev.C 72, (2005)

Ivan Vitev&

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Light Cone Wave Functions

22

2

2 2 (1 ) (4 4

4

)

(( , )

1 )Q qk x

k xx

xx

x

m mE p

2 22

surv. (* ( , ), )f iP L dxd k x kx k

S.Brodsky, D.S.Hwang, B.Q.Ma, I.Schmidt, Nucl.Phys.B 592 (2001)

2

32

2 2

; ,2 2

1 ;

)

,

( ,n

i iM

i i

n n

i i i i ii

i

i

i i

dx d kP P

x

x k i k x P x P

k x

Fix two momentum scales

2

surv.diss ln 1 ( )q

P td

dtL

• Find dissociation time

Ivan Vitev&

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Heavy Meson Dissociation at RHIC and LHC

Coupled rate equations

• The asymptotic solution in the QGP - sensitive to t0~0.6 fm and expansion dynamics

• Features of energy loss

• B-mesons as suppressed as D-mesons at pT~ 10 GeV (unique feature)

A.Adil, I.V., hep-ph/0611109

1

/20

1

/20

( , ) ( , )

( / , )

( / , )

( , )

( / , )

( , )

( / , )

1

1 1 + ( )

1

1 1

(

+ ( )

, ) ( , )

form T

diss T

diss T

for

t t

Q H

t t

m

H

H H

Q

T T

H

QT T

T

QT

T

Q

f

f p

p t

p x t

p t

p z

dx xx

dz

f p

t f

t f p t

p x t

f p z tzt

z

t

D

p

1, 1x z

Ivan Vitev&

15

Quenching of Non-Photonic Electrons

A.Adil, I.V., hep-ph/0611109• PYTHIA used to decay all B- and D-mesons / baryons into (e++e-)

Predictions also made for Cu+Cu (RHIC) and Pb+Pb (LHC)

• Suppression RAA(pT) ~ 0.25 is large

• B-mesons are included. They give a major contribution to (e++e-)

1

/( ; ) 1/n

ii

B b Df c

• Similar to light , however, different physics mechanism

0

2

2coll

(/

)/

ee

AAAA

TT

epp T

dN dyd p

N d dy pp

dR

Ivan Vitev&

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Example at the LHC

35002000/ dydN g

• For the same t0~0.6 fm the suppression is similar to RHIC since the larger parton density is compen-sated by the stiffer spectra

• Sensitivity to the formationtime

What can we learn fromHeavy Flavor at the LHC?

)(then

)(then

0

0

TAA

TAA

pRt

pRt

t0 – QGP formation time

Ivan Vitev&

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• How about cold nuclear matter effects?

Part III [ The Cold ]

Ivan Vitev&

18

/Pb Pb p PbR R

preliminary

When One ≠ One

• Theoretical results: cancellation between factor of 4 Cronin enhancement and 2- to 3-fold quenching

Ncoll,Pb+Pb = 807 ± 81

• Experimental findings:

S.Bathe., LANL seminarI.V., Phys.Lett.B 632 (2005)

• With any multiple scattering effect there is no reason to expect 1)( TAB PR• If one understands this in A+A collisions one should also accept this is p+A collisions

Ivan Vitev&

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• Bertsch-Gunion Energy Loss

• Initial-State Energy Loss• Final-State Energy Loss

M.Gyulassy, P.Levai, I.V., Phys.Rev.Lett. (2000)

Regimes of QCD Radiative Energy Loss

2

1~ B

21

2

12

1cos.2~

HBHB

I.V., hep-ph/0703002

I.V., hep-ph/0703002

G.Bertsch, F.Gunion., Phys.Rev.D (1982)

Limited applicability(no hard scattering)

R.Baier et al., Nucl.Phys.B (1997)

P.Arnold,G.Moore, L.Yaffe, JHEP (2003)

E.K.Wang, X.N.Wang, Phys.Rev.Lett. (2002)

Best studiedQGP applications

New resultDominant cold nuclear matter effect

2

1

112

1cos1.~

CBC

Ivan Vitev&

20


• Initial-State Energy Loss

• Final-State Energy Loss

0

(1) lng

E L Econst

E Q

2 20ln /

(3)g

E QE Lconst

E E

0(2) ln

(2) (1)

g

QE Lconst

E

const const

I.V., hep-ph/0703002

Quantitative Behavior of E-loss

<<

Correct way to study E-loss in nuclei: in the rest frame of the nucleus

)cosh( targetjet yypE T

Ivan Vitev&

21

Consistency of Cold Nuclear Matter Tomography

GeV2Tp

TeV20jet E

• Dynamical shadowing (coherent final-state scattering) HT/LT?

• Cronin effect (initial-state transverse momentum diffusion)

• Initial state energy loss (final state at these energies - negligible)

22

1/3( ) 2

2

( 1)( , ) ,LTA

T T

xF x Q FA Q

Ax

Q

Consistency in the extracted cold nuclear matter properties

2 2

,( ) 0

2 A

q g F

C

C r

2 2( , )1

,/

xx Q Q

E E

medvactotkkk 222

Ivan Vitev&

22

Evidence at all Rapidities

Very similar behavior of charmquarks (D-mesons) to light hadrons

I.V., T.Goldman, M.Johnson, J.W.Qiu, Phys. Rev. D 74 (2006)

Experimental y = 1.4-2.2

0d A X d A D X

Even at mid-rapidity seemingly small modification 10% - 25% may arise from cancellation of nuclear effects as large as a factor of 2

Ivan Vitev&

23

Example at the LHC

I.V. in preparation

• How important is cold nuclear matter energy loss? – Has the same effect as doubling the parton rapidity density

• At the expected larger medium density and stiffer spectra at the LHC there is reduced sensitivity to the medium density 0-10% central Pb+Pb

0-10% central Pb+Pb1

)loss-E Cold ,2000/(

)loss-E Cold no,4000/(

dydNR

dydNRg

AA

gAA

• Consistent inclusion of cold nuclear matter energy loss may be more important at the LHC (Y=0)

Ivan Vitev&

24

Summary

Cold nuclear matter effects• Calculated dynamical shadowing, Cronin and initial-state energy los • Quantitatively important both in p+A and A+A recations • Affect in a major way the extraction of the QGP properties at the LHC

Collisional QGP-induced B- / D-meson dissociation• Derived formation and dissociation times in the QGP. They are short • B-mesons are as suppressed as D-mesons at pT ~ 10 GeV, unique• At the LHC obtain the same qualitative behavior as at RHIC

Light flavor quenching

• Requires consistency: already a RHIC models sacrifice this consistency• At LHC: regions of less suppression than at RHIC, new effects

Ivan Vitev&

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Energy Loss in QCD

Establishing the E-loss mechanism

2q

0 3p p0 'p

3 'p

2q

0 3p p0 'p

3 'p

• Collisional:

• Radiative:

/ 4 2220

( )coll el

sdE ddq z

qE q

dz d

.( , )colldE

const Edz

0

raddE E

dz X

min

1 22

1 1 1( , )

rad

R xq

dEC x dx d k f k q

dz x kE

Important: mass dependence

Important: no mass dependence

Qualitatively:

Qualitatively:

Ivan Vitev&

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Strategy for Calculating HF Suppression

• Calculate the baseline D- and B-meson cross sectionsin p+p collisions

• Calculate the fragmentation probability of heavy quarks

• Solve the system of coupled rate equations and predict the heavy quark (single electron) suppression

• Calculate the QGP-induced dissociation probabilityfor heavy mesons

Ivan Vitev&

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Detailed Analysis to LO

Single inclusive D - mesons D - meson triggered back-to-back correlations

Flavor excitation Flavor creation

F.Olness et al., Phys.Rev.D59 (1999)

Two different expansions

Faster convergence ofthe perturbative series Slower convergence of

the perturbative series

Ivan Vitev&

28

c g c g c q q c q q

Heavy Quark Production in p+p Collisions

• Gluon fusion is not the dominant process in single inclusiveopen charm (bottom)production

I.V.,T.Goldman,M.Johnson,J.W.Qiu, Phys.Rev.D74 (2006)

p p D X

• Comparable to “NLO” results: (under-predicts the cross section by 30% - x 2 )

Ivan Vitev&

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Fragmentation Probability for Heavy Quarks

Recall

• Fragmentation probability

• Time-dependent implementation

1

/( ; ) 1/n

ii

B b Df c

1

,0 ,2

/ ( , ) ( ), / ,i iD B c b ii iD z Q dz Bf D c b

form form /

1 2

0( , , , ) ( , )

ihi Qi

h Qz m M p D z Q dz

form

( ) (0)expQ Q

tN t N

2 2

r

2

fo m

(0.2 . ) 2 (1 )1( , , , )

(1 ) (1 )

( , , , ) /(1 )

h Q

h Q Q

qh

GeV fm z zy z m M p

p k z z z

z m M p y

p

m M

B-mesons

( )Bx z

( )Bx z

K.Cheung,T.Z.Yuan, Phys.Rev.D53 (1996)

Ivan Vitev&

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22

2

2 2 (1 ) (4 4

4

)

(( , )

1 )Q qk x

k xx

xx

x

m mE p

• Longitudinal momentum fractions

2 2 22 2 2j i ji i i

i i j j

m m km m k

x x x x

From general theory of LCWF for the lowest-lying Fock state

• Results for heavy flavor

Meson boost – equal quark rapidity

Begin to understand hadron structure / parton distributions from first principles

Ivan Vitev&

31

Heavy Meson Propagation in Dense Matter

• Solve for the color and kinematic structure of this operator (automatically ensures unitarity)

( )n

• Single scattering in the medium

21 2

2 22

*( ) ( '~ ') ( )' M p q M pd q dd

q qqq

qel

d

222

21

2 *(1

2' ) ( )~ ) '('

d el

dM p q qd q d q q qM p

q

q q’

q’q

Ivan Vitev&

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• Expansion in Fock components

S.Brodsky, D.S.Hwang, B.Q.Ma, I.Schmidt, Nucl.Phys.B 592 (2001)

2

32

2 2

; ,2 2

1 ;

)

,

( ,n

i iM

i i

n n

i i i i ii

i

i

i i

dx d kP P

x

x k i k x P x P

k x

Fix two momentum scales

• Transverse momentum scale

( )V r brr

q, g

P

P

Fourier transform to momentum space

02 10 max( ( )) 2 3,a r r a GeV

M. Avila, Phys.Rev.D49 (1994)

Cornell potential

20

2 1

2k

a Typical transverse momentum squared

Ivan Vitev&

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22

2

2 2 (1 ) (4 4

4

)

(( , )

1 )Q qk x

k xx

xx

x

m mE p

• Longitudinal momentum fractions

2 2 22 2 2j i ji i i

i i j j

m m km m k

x x x x

From general theory of LCWF for the lowest-lying Fock state

• Results for heavy flavor

Meson boost – equal quark rapidity

Begin to understand hadron structure / parton distributions from first principles

Ivan Vitev&

34

Heavy Meson Propagation in Dense Matter

• Solve for the color and kinematic structure of this operator (automatically ensures unitarity)

( )n

• Single scattering in the medium

21 2

2 22

*( ) ( '~ ') ( )' M p q M pd q dd

q qqq

qel

d

222

21

2 *(1

2' ) ( )~ ) '('

d el

dM p q qd q d q q qM p

q

q q’

q’q

Ivan Vitev&

35

Heavy Meson Propagation in Dense Matter II

• Heavy meson acoplanarity: 2 22 2q

LK

Initial distribution:i

Resum multiple scattering in impact parameter (B,b) space

• Broaden (separate) the q q-bar pair:

2 2

0

12 2 2 2 ( )

( )

L

q q

Ll dl

l

Ivan Vitev&

36

Deriving Heavy Meson Dissociation

2 2

surv. surv., 01 1q q

P L P L

• Distortion of the light cone wave function leads to meson decay

2 22

surv. (* ( , ), )f iP L dxd k x kx k

Properties of survival probabilities:

Dissociation time: 2

surv.diss ln 1 ( )q

P td

dtL

Meson survival probability:

Ivan Vitev&

37

Langevin Simulation of Heavy Quark Diffusion

Radiative energy loss is dominant except for b-quarks and very small systems

Input in a Langevin simulation of heavy quark diffusion

H. van Hees, I.V., R. Rapp, in preparation

• Drag coefficient:

1( , )i

i

i

Ap t

p tp

1

2( , )ji

j ipp

pt

tB

• Diffusion coefficient:

g

( , )( , )( ,( , ) )ii

i ijiA p

f p tp f p tB p

t p pt t

Equilibration is imposed by Einstein’s fluctuation-dissipation relation:

( ) (), ,) ( )( iT t E tB Ap p pt

Ivan Vitev&

38

Transport + Quenching Approach

• The suppression and v2 are large when e-loss and q-resonance interactions are combined

• Normal hierarchy: c quarks are significantly more suppressed than b-quarks

Numerical results for heavy quark diffusionH. van Hees, I.V., R. Rapp, in preparationResults are preliminary

Ivan Vitev&

39

• LDRD DR proposal

• Best reason to measure D- and B-mesons separately

Experimental Tools

• Used to leverage full scale detector upgrade (FVTX)

Experimentally validate / disprovetheories

( ; ) ( ; )AA T AA TR R pBp D ( ; ) ( ; )AA T AA TR R pBp D

Collisional dissociation

Mainstreamapproach

Ivan Vitev&

40

Ivan Vitev&

41

Comparison to Other Models

Wicks et al.

Ivan Vitev, LANL

How do you build from T = 400 MeV

22ˆ 10 /

g

q GeV fm LHC: from T = 1 GeV

22ˆ 100 /

g

q GeV fm

Wang

Ivan Vitev&

42

Come to your one conclusions

• One should use adequate energy-momentum conserving formalism

• Instead authors scurry around to seek for justification

- Argued that transverse expansion leads to 4 times energy loss, Armesto, Salgado, Wiedeman (2005)

– wrong on the basis of elementary physics (translational invariance)

- Killed even by the original authors, Baier et al. (2006)

- Found comfort in String theory, Rajagopal, Wiedeman (2006)

Ivan Vitev&

43

Langevin Simulations of C- / B-Quark Diffusion

Fokker-Plank diffusion equation

• Expansion of gain / loss terms to second order

Equilibration is imposed by Einstein’s fluctuation-dissipation relation:

H. van Hees, R. Rapp, Phys.Rev.C71 (2005)

( , )( , )( ,( , ) )ii

i ijiA p

f p tp f p tB p

t p pt t

• Model of quark-resonance interaction near the QCD phase transition

( ) (), ,) ( )( iT t E tB Ap p pt

( , )iA p t - drag ~ equilibration1/

( , )jiB p t - diffusion ~ fluctuation1/

• Efficient at

• Include e-loss at high pT

resonances M

Ivan Vitev&

44

High Twist Shadowing Theory (Dynamical)

Coherent final state scattering theory Shadowing is the ratio of DIS reduced cross sections – structure functions

J.W.Qiu, I.V., Phys.Rev.Lett. 93 (2004)

2 2

2 20 0

2 00

3 ( ) 3 ( )( lim ()

8 2 8)x

i p ys sQ dy Qe p F F p y

r rxG x

• Dynamical parton mass (QED analogy):

2 1/32dynm A

*, *g

• QCD factorization approach, background color magnetic field

Calculate versus parameterize

S.Brodsky et al, Phys.Rev.D65 (2002)

Ivan Vitev&

45


• Initial-State Energy Loss

• Final-State Energy Loss

0

(1) lng

E L Econst

E Q

2 20ln /

(3)g

E QE Lconst

E E

0(2) ln

(2) (1)

g

QE Lconst

E

const const

I.V., in preparation

Regimes of QCD Radiative Energy Loss

Ivan Vitev&

46

Nuclear Effects at Forward Rapidity (Light H)

I.V., in preparation

• The most detailed calculation so far at forward rapidity

• Dynamical shadowing (FS)

• Cronin effect (IS)

• Initial state energy loss (IS)

• Consistency in the extracted cold nuclear matter properties

22

1/3( ) 2

2

( 1)( , ) ,LTA

T T

xF x Q FA Q

Ax

Q

2

2 2

2

2

For 2

med

tot vac med

k

k k k

cmx^

^ ^ ^

D =

D = D + D

2 2( , )1

,/

xx Q Q

E E

• Now apply for heavy quarks

Ivan Vitev&

47

• Bremsstrahlung is the most efficient way to lose energy since it carries a fraction of the energy

p

k xp k 2

2

1 1 ( )ln ln

2 2g k xpy

k k

• Acceleration: radiation

1q 1q 2q 3q 4q 4q 5q 5q 6q 6q 7q

f

1

1

1

1 1

1 1

1 1

...2 2

( ... )( ... ) 2 2

...,

( ... )

... ...

( ... ) ( ... )

n

m

m

m n

m n

m n

i ii i

i i

i i j ji i j j

i i j j

k q qkH C

k k q q

k q q k q qB

k q q k q q

• Formation time: coherence effects

1

1

2 21 1

0

21

...

( ),

( ... )m

m

f i f

i ii i f

k k q

k k

k q q

k

• Onset of coherence • Full coherence1f g

D

1

gfD

L

LPM

Understanding the LPM Effect

Ivan Vitev&

48

Cold Nuclear Matter Effects on D- Production

Very similar behavior of charmquarks (D-mesons) to light hadrons

E-loss plays a similarly important role

I.V., T.Goldman, M.Johnson, J.W.Qiu, Phys. Rev. D 74 (2006)


Nuc

lear

sup

pres

sion

in d

+A

rea

ctio

ns

0d A X d A D X

Important at forward Y. Not so important at Y = 0

Ivan Vitev&

49

Outline of the Talk

Energy loss in QCD

• Radiative and collisional energy loss, recent developments • Application to A+A collisions and p+A collisions

Applications to heavy quarks • Discrepancy between PQCD and c- and b-quark quenching• Transport+quenching approach to D- and B mesons

Alternative theory of heavy flavor suppression• In-medium formation and dissociation of D- and B- mesons• Suppression of non-photonic electrons

Conclusions

I.V., work in progressA.Adil and I.V., hep-ph/0611109H. van Hees I.V. and R. Rapp, work in progress

Based upon:

Ivan Vitev&

50

• Collisional: / 4 2220

( )coll el

sdE ddq z

qE q

dz d

Arises from the acceleration of the charges in the target. No significant mass dependence

2

0

1coll qdE

dz Q

/ 0EE E 2q

0 3p p0 'p

3 'p

Types of Energy Loss

• Radiative:min

1 22

1 1 1( , )

rad

R xq

dEC x dx d k f k q

dz x kE

0

raddE E

dz X

2q

0 3p p0 'p

3 'p

Arises from the acceleration of the incident charge.Can have significant mass dependence

/ 0EE E

/ EE E const Much more efficient

Ivan Vitev&

51

I.V., Phys.Lett.B 639 (2006)

Light Hadron Quenching in A+A


Centrality

C.M

. en

ergy

D. d’Enterria, Eur.Phys.J C (2005)

Theory (constrained) / Experiment

3

2

g chdN dN

dy dy

Ivan Vitev&

52

• Cancellation of collinear radiation

I.V., Phys.Lett.B630 (2005)

What Happens to Medium-Induced Radiation?

In A+A

+2Re

2

x

2 *2 Resin *

...gmed

a b c

dNM M M

d d d

0, / 0k k

Correlated!

2

2

1 1 ( )ln ln

2 2g k xpy

k k

How about p+A?

First quantitative PQCD calculation

Ivan Vitev&

53

I. Heavy Ion Theory Effort at LANL

Core theory staff• Terry Goldman (T-16, quark models, neutrinos, PQCD)• Rajan Gupta (T-8, energy future, LQCD)• Mikkel Johnson (P-25, energy loss, shadowing, PQCD)• Emil Mottola (T-8, gravity, black holes, non-equilibrium FT)

J.Robert Oppenheimer fellow• Ivan Vitev (P-25 & T-16, energy loss, shadowing, PQCD)

External Collaborators• Miklos Gyulassy (Columbia U.)• Boris Kopeliovich (Heidelberg U., Germany)• Peter Levai (KFKI, Hungary)• Jianwei Qiu (Iowa State U.)• Joerg Raufeisen (Heidelberg U., Germany)• Ivan Schmidt (Santa-Maria U., Chile)

Columbia university

Collaborating institution

Ivan Vitev&

54

Publications and Workshops

Publications.

• Ivan Vitev, LARGE ANGLE HADRON CORRELATIONS FROM MEDIUM- INDUCED GLUON RADIATION.

Phys.Lett.B630:78-84,2005. • Ivan Vitev, T. Goldman, Mikkel Johnson, Jian-Wei Qiu, NUCLEAR EFFECTS ON OPEN CHARM PRODUCTION IN

P+A REACTIONS. HEP-PH 0511220 • Ivan Vitev, JET QUENCHING AT INTERMEDIATE RHIC ENERGIES. Phys.Lett.B606:303-312,2005. . • Mikkel B. Johnson, PROPAGATION OF FAST PARTONS IN THE NUCLEAR MEDIUM. Eur.Phys.J.A19:2004. • B.Z. Kopeliovich, J. Nemchik, I.K. Potashnikova, M.B. Johnson, I. Schmidt, BREAKDOWN OF QCD

FACTORIZATION AT LARGE FEYNMAN X. Phys.Rev.C72:054606,2005. • Fred Cooper, Ming X. Liu, Gouranga C. Nayak, J / PSI PRODUCTION IN PP COLLISIONS AT S**(1/2) = 200-GEV

AT RHIC. Phys.Rev.Lett.93:171801,2004.

• Jian-Wei Qiu, Ivan Vitev, RESUMMED QCD POWER CORRECTIONS TO NUCLEAR SHADOWING,

Phys.Rev.Lett.93:262301,2004Conferences / Workshops• Emil Mottola, organizer, “QCD and Gauge Theory Dynamics in the RHIC Era”, April 2002, KITP• Rajan Gupta, organizer, “Modeling the QCD Equation of State at RHIC”, February 2006, LLNL• Ivan Vitev, organizer, “LHC workshop at PANIC’05” November 2005, Santa Fe• Terry Goldman, Mikkel Johnson, organizers, “PANIC’05” November 2005, Santa Fe (Martin Cooper, Joe Carlson, P-25, T-16 )

LANL - LLNL

Ivan Vitev&

55

II. Theory: Jet Quenching

Breakthrough theoretical work:

• Formalism for calculating the energy loss: GLV (Gyulassy-Levai-Vitev)

• Implementation of energy loss, Croninscattering in PQCD hadron production

TNN

TAA

collTAA dpdd

dpdd

NpR

/

/1),(

2

2

Nuclear modification

M.Gyulassy,P.Levai,I.Vitev Phys.Rev.Lett. 85 (2000);

Nucl.Phys.B571 (2000); Nucl.Phys.B594 (2001)

I.Vitev, M.Gyulassy, Phys.Rev.Lett. 89 (2002);

I.Vitev, Phys.Lett. B562 (2003); Phys.Lett. B630 (2005)

I.Vitev,M.Gyulassy,P.Levai,I.Vitev, in preparation

Ivan Vitev&

56

PQCD Factorization and Energy Loss Theory

11

2

/1 1 2

1 1

1

2min min 1

2( )(

()

))(

a b

sa b a b

ab

h

cd a bx x

ab cT

dc

hNNd

dx dD z

zx x x

x xSd pM

ydas

ff ®= å ò ò

(1) R s

3(1)

2

2g

g

2R s

2CE Log ... ,

4

Static medium

9 C 1E Log ... ,

4 A

(L)

dNdy (L

1+1D

)

L 2E

Bjo

L

2EL

L

rken• Bjorken expanding medium: 0

0( ) ( )

M.Gyulassy,I.Vitev,X.N.Wang, Phys.Rev.Lett. 86 (2001)

Challenge: connection

v c

Box of plasma

0p p X

Pio

n cr

oss

sect

ion

Ivan Vitev&

57

I.Vitev,in preparation; hep-ph/0511273

Results on Energy and Centrality Dependence


Centrality

C.M

. en

ergy

D. d’Enterria, Eur.Phys.J C (2005)

I.Vitev, M.Gyulassy, Phys.Rev.Lett. 89 (2002)I.Vitev, Phys.Lett.B 606 (2005)

Theory / Experiment

3

2

chg d

d d

dN

y y

dN

d

Experimentallymeasured

Pio

n su

ppre

ssio

n in

A+

A r

eact

ions

Pio

n su

ppre

ssio

n in

A+

A r

eact

ions

0A A X

Ivan Vitev&

58

E-loss in Back-to-Back Di-jets and Correlations

1 2

1 2

1 2(2) 1 2

1 2 1 2

h hAA

T Th hApp

T T

A

bin

d

dy dy dp dp

d

dy d pN

dp

R

y d

1

1

1

1

2/

1 / 2

/0 / 2

2

1

/ ( ) (1

( )

( )

)1 1

( ) ( )

h d med

T gh g g vac

g

h d

g

zD f

p dzD z d f

z

dN

D

z

z

d d

0

0

/E E

A+A

Tag

I.Vitev, Phys.Lett.B630 (2005)

• Multi-particle modification• Angular gluon distribution

Tw

o pa

rtic

le s

uppr

essi

on /

enha

ncem

ent i

n A

+A

rea

ctio

ns

1 2A A h h X

See talk by M. Brooks

Ivan Vitev&

59

Theory: High Twist Shadowing Theory

Coherent final state scattering theory Shadowing is the ratio of DIS reduced cross sections – structure functions

J.W.Qiu, I. Vitev, Phys.Rev.Lett. 93 (2004)

2 2

2 20 0

2 00

3 ( ) 3 ( )( lim ()

8 2 8)x

i p ys sQ dy Qe p F F p y

r rxG x

• Dynamical parton mass (QED analogy): 2 1/32dynm A

Data from: NMC

*, *g

• QCD factorization approach, background color magnetic field

Shadowing

Twist Dimension Spin O

Power suppressed ~ 1/QT

Ivan Vitev&

60

A-, x- and Q2-Dependence: Numerical Results

222 ( ) 2 ( ) 2

2

1/

2

3( 1)( , ) , = 1 ,dynLT LTA

T T T

mxF x Q F

Ax Q F x Q

QA

QA

• The scale of higher twist per nucleon is small: 2 20.1 0.12 GeV

J.W.Qiu, I. Vitev, Phys.Rev.Lett. 93 (2004)

• The nuclear effect is of power law nature: Q2 dependent

2 ) 22

2( 2 4

( , ) ( , ) ( , )A AL TLT

LF x Q x Q F QQ

A F x

Sup

pres

sion

in D

IS S

truc

ture

Fun

ctio

ns

Sup

pres

sion

in D

IS S

truc

ture

Fun

ctio

ns

Ivan Vitev&

61

Shadowing in Neutrino+A and p+A Reactions

2( )( ) b

ab cdbb

xF x M

x

f®=

21/ 3( 1( ) )b b b dx C A

tF x F x

J.W.Qiu, I. Vitev, Phys.Lett.B 587 (2004)

J.W.Qiu, I. Vitev, Phys.Lett.B 632 (2006)

p+A

STAR

• DIS-like t-channel FS scattering

g u sea u valS S S

Nuc

lear

sup

pres

sion

in p

+A

rea

ctio

ns

Str

uctu

re F

unct

ions

No nuclear effect

d A h X

• Dynamical shadowing for sea quarks, valence quarks and gluons

Ivan Vitev&

62

Theory: Energy Loss in Cold Nuclear Matter

M.B.Johnson et al., Phys.Rev.C72 (2005)

I.Vitev,T.Goldman,M.Johnson,J.W.Qiu, in preparation

• Evidence from low energy p+A reactions

( , , ) 0.25Ty y p A Eff. E-loss

( ) 2

2 2 2 2( )

BGg s

A

d qNC

qdyd k k k

(1 ) 1gN

F F FS x x Suppression

( 1) 1gN y

+ +2 2~ | |B

Nuc

lear

sup

pres

sion

in d

+A

rea

ctio

ns

Nuc

lear

sup

pres

sion

at f

orw

ard

rapi

dity

d A h X

See talk by M. Brooks

2 22

1 2 2 21

( ) /( , , )

( ) /

ABT

y T ABT

d y dyd pR p y y

d y dyd p

Ivan Vitev&

63

c g c g c q q c q q

+ ...+ ...

III. Heavy Quark Production and Modification

Gluon fusion is not the dominantprocess in open charm production

I.V.,T.Goldman,M.Johnson,J.W.Qiu, Phys.Rev.D74 (2006) • Proposed back-2-back charm triggered correlations

( ) 2

( ) 2

/

/

process iT

process iT

i

d dyd pR

d dyd p

p p D X

Ivan Vitev&

64

Nuclear Matter Effects on Charm Production

PHENIX data

(min. ) 0.25,y bias No Cronin Very similar behavior of charmquarks (D-mesons) to light hadronsE-loss seems to play a similarly

important role

I.Vitev,T.Goldman,M.Johnson,J.W.Qiu, in preparation hep-ph/0511220


LDRD: “Heavy Quarks as a Probe of a New State of Matter”

Nuc

lear

sup

pres

sion

in d

+A

rea

ctio

ns

Nuc

lear

sup

pres

sion

in d

+A

rea

ctio

ns

0d A X d A D X

See talks by M. Brooks and P. McGaughey

Ivan Vitev&

65

2 2

q

E E FM

Reduce large theoretical spreadof "melting" temperatures of

Future / LDRD Research Directions

F.Karsch, Nucl.Phys.A698 (2002)

qq

• Lattice QCD equation-of-state and heavy quarkoniaFrom Nt=4 to Nt=6, 8 lattices Improved lattice actions

• E-loss of heavy quarks at

• Transport coefficients of the QGP

I.Vitev

0Y

Thermal and electrical conductivityNon-equilibrium field theory

Fra

ctio

nal q

uark

ene

rgy

loss

Ene

rgy

dens

ity

See talk by P. McGaughey

R. Gupta

I. Vitev

E. Mottola

Ivan Vitev&

66

Summary of Theory Effort / Directions

Heavy Ion Theory at Los Alamos • 4+1 staff, new external collaborations, extensive publication record.

Participated / organized HIT conferences / workshops

Recent Theoretical Progress • Establishing the jet quenching theory: verified predictions versus C.M.

energy, predictions versus centrality Cu+Cu, Au+Au• Understanding high twist shadowing: final state interactions. DIS structure

functions F1, F2, neutrino-nucleus reactions F3, p+A reactions • Energy loss in cold nuclear matter: understanding the p+A rapidity

asymmetry and verification at lower C.M. energies.

Future Theoretical Developments, LDRD• Heavy quark production / modification: charm on gluon scattering• Energy loss mechanism for heavy quarks: non-zero Y, novel e-loss• Transport coefficients: electrical and thermal conductivity of the plasma• Lattice QCD Equation-of-State and heavy quarkonia: improved simulations

Ivan Vitev&

70

Analytic Models of Jet Quenching

2 /2 23

1 1

1 '1

AA n

T part

n

T

RNp

p

20( ) nn

T T T

d a a

dyd p p p p

/ 2 /32 3par

g

t

L dNA

A dEN

y

E

PQCD baseline:

• Predictions

2/3

2/3

ln

exp

AA part

AA part

R N

R N

I.Vitev,in preparation; hep-ph/0511273

• Centrality dependence

Verified with PHENIX and STAR

GLV E-loss:

Quenched PQCD: 2 )/(1n nT TT T

d a

dy p p pd p

Comparison

consistency of jet quenching predictions at the lhc

Documents