new theoretical approaches to heavy flavor suppression
DESCRIPTION
New Theoretical Approaches to Heavy Flavor Suppression. A. Adil and I.V., hep-ph/0611109, H. van Hees I.V. and R. Rapp, in progress. Ivan Vitev, T-16 and P-25, LANL. Energy loss in QCD – application to light / heavy hadrons Implementation in heavy quark diffusion simulations - PowerPoint PPT PresentationTRANSCRIPT
Ivan Vitev&
New Theoretical Approachesto Heavy Flavor Suppression
Ivan Vitev, T-16 and P-25, LANL A. Adil and I.V., hep-ph/0611109, H. van Hees I.V. and R. Rapp, in progress
• Energy loss in QCD – application to light / heavy hadrons • Implementation in heavy quark diffusion simulations • Alternative theory of heavy flavor suppression in the QGP• Conclusions
Ivan Vitev&
I.V., Phys.Lett.B 639 (2006)
Light Hadron Quenching in A+A
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
.( , )colldEconst E
dz
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
Very important: Laldau-Pomeranchuk-Migdal effect
Important: mass dependence
Ivan Vitev&
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
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)
Ivan Vitev&
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&
Collisional versus Radiative Energy Loss
Radiative energy loss is dominant except for b-quarks and very small systems
Input in a Langevin simulation of heavy quark diffusionH. 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:
Two regimes (light partons):
jet coll radt L E E
jet coll radt L E E
g
Ivan Vitev&
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&
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
20 fm 1.5 fm 0.4 fmform ( 10 )Tp GeV
PartonHadron
p
zp
(1 )z p
~ QCDk
B
D
QGP extent
2 2 2
form
(0.2 . ) 2 (1 )1
(1 ) (1 )
/(1 )
h q
Q
GeV fm z z py
p k z m z z M
y
2
, ,02
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&
Light Cone Wave Functions
• Distribution of internal momenta
…and their distortion
A.Adil, I.V., hep-ph/0611109
S.Brodsky, D.S.Hwang, B.Q.Ma, I.Schmidt, Nucl.Phys.B 592 (2001)
2
32
; ,2 2
( ,
)
; ,
ni i
Mi i
i i i
i i i
dx d kP P
x
i k x P
k x
x P
2
2
222 (1 ) ( )
(
4 4
4
,1
( ))
Q qm mE
k x x
x xk x xp
2 2
surv. surv., 01 1q q
P L P L
• Heavy meson acoplanarity
• Distortion of the light cone wave function (meson decay)
2 22
surv. (* ( , ), )f iP L dxd k x kx k
2 22 2q
LK
Ivan Vitev&
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&
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&
Summary of Open Heavy Flavor Suppression
Langevin simulation of heavy quark diffusion • Calculated drag and diffusion from the collisional and radiative e-loss • Combined with a chiral model of quark-resonance interactions: obtained
large v2 and RAA . Work in progress• Normal suppression hierarchy: B- much less suppressed than D- mesons
Collisional QGP-induced B- / D-meson dissociation• Derived formation and dissociation times in the QGP. They are short • Solved the set of coupled rate equations. More sensitive to QGP properties and formation / expansion dynamics than e-loss• Found that suppression of non-photonic electrons from heavy mesons, including B, is large. Not inconsistent with light pions • B-mesons are as suppressed as D-mesons at pT ~ 10 GeV, unique
Toward experimental resolution of the B- / D- puzzle • Identify the B- and D-meson contribution to the inclusive electron spectra and the suppression factor RAA separately for Bs and Ds
Ivan Vitev&
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&
• 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&
• 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
1gf
D
L
LPM
Understanding the LPM Effect
Ivan Vitev&
• Bertsch-Gunion Energy Loss
• 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&
I.V., Phys.Lett.B 639 (2006)
Light Hadron Quenching in A+A
Establishing the E-loss mechanism
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&
Nuclear Effects at Forward Rapidity
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
Ivan Vitev&
• 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&
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&
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&
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&
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&
I.Vitev,in preparation; hep-ph/0511273
Results on Energy and Centrality Dependence
Establishing the E-loss mechanism
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&
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&
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&
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&
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&
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&
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&
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
Experimental y = 1.4-2.2
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&
2 2
q
E E FM
Reduce large theoretical spreadof "melting" temperatures of
Future / LDRD Research Directions
F.Karsch, Nucl.Phys.A698 (2002)
• 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&
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&
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