What we havelearned at RHIC andhomework to LHC
Success of soft physics andjet as a homework from RHIC
to LHC

Yasuo MIAKE
Univ. of Tsukuba

Yasuo MIAKE, 2010.07.07,Tsukuba

1Quark-Gluon Plasma
RHIC(200GeV)
since 2000

LHC(5.6TeV)
soon✓Physics of QCD in extremeT, ρ and small x✓Nucleus-Nucleus collisions✓˜ 10 years of RHIC runningYasuo MIAKE, 2010.07.07,Tsukuba

2Soft & Hard comp. in pp✓At ISR in 1972, deviation from

hard
soft

the mt scaling at high pt region
is observed as a first time.
✓Binary parton scattering
followed by fragmentation
produces back-to-back jet.
✓Main source of high pt
particles.
back-to-back jet

d 3σ
mt
C1
E 3 = C0 exp(− ) +ndp
T0( pt + p0 )Yasuo MIAKE, 2010.07.07,Tsukuba

3Outline✓Soft component and hard component✓RHIC• Soft physics➡well understood• Hard physics➡poor understanding✓RHIC vs. LHC• Expected property of QGP• Plenty of jets

✓Physics of Jet quench✓Summary
Yasuo MIAKE, 2010.07.07,Tsukuba

4

Relativistic AA collision

QGP

Yasuo MIAKE, 2010.07.07,Tsukuba

5

Key1; Time Evolution✓It is like Big Bang.
✓Time evolution in
statistical nature• Parton cascade followedby partonic
thermalization (QGP)• Hadron production• Freezeout of v2 ?
• Chemical freeze-out• Kinematical freeze-out

Need consistent understanding of these epocs,
in particular, aspects of statistical nature.
Yasuo MIAKE, 2010.07.07,Tsukuba

6

Key2 ; Statistical Nature
3

�QGP ∼ 2 [GeV/fm ]
�QGP
2GeV
< nq,q̄ > ∼∼∼5< mT >
1GeV
1
λq =
nσqq
1
∼
= 0.2 [fm]5 × 0.4
λq � Rsystem
4[fm2 ]σN N∼
∼1
∵ σqq ∼nq
3

Ex. Lattice QCD

Animation by Jeffery Mitchell (Brookhaven National
Laboratory). Simulation by the UrQMD Collaboration✓What we expect,• Statistical physics at quark level• Hydrodynamical behavior at quark level

Yasuo MIAKE, 2010.07.07,Tsukuba

7

Soft comp.
Statistical andCollective Nature
characteristic to the
QGP formation

Yasuo MIAKE, 2010.07.07,Tsukuba

8

Chemical Eq. from particle
yield ratio
M.Kaneta, N.Xu, nucl-th/0405068

gi
ni = 2
2π

� ∞
0

p2 dp
e(Ei −µi )/T ± 1

Tch [MeV]

200
150
100
50
0
0

100 200 300 400
Npart✓Only few parameters fit every ratio very well !
✓Tch stays constant from peripheral to central collisions
Yasuo MIAKE, 2010.07.07,Tsukuba

9

Kinematical Distr.:
Transverse mass distr.
mt =

2
t

p +m

2

PHENIX, PRC69,034909(2004)✓ Exponential in mt• Known as mt scaling• Thermal distr.
✓ Flatter mt distr for heavier

particle mass
• Mass Ordering of Slope param.
• Effect of Collective Flow

Yasuo MIAKE, 2010.07.07,Tsukuba

1
2
T ≈ T0 + m v r
2

Collective
Flow
10

Blast Wave Model⎛ p sinh ρ ⎞ ⎛ m cosh ρ ⎞R
1 dN
= A ∫ 0 f (r)rdrmT I 0 ⎜⎜ T⎟⎟ K1⎜⎜ T⎟⎟mT dmT⎝ Tfo ⎠ ⎝ Tfo⎠

PRC48(1993)2462.

−1

ρ(r) = tanh (βT ) ⋅ r/R

I0 , K1: modified Bessel function
Phobos, J.Phys.G34,S1103-7(2007)€
PHENIX, PRC69,034909(2004)€✓Good tool to separate
Yasuo MIAKE, 2010.07.07,Tsukuba

thermal and collective✓Well describe < 2 GeV/c

11

Time evolution &Freeze-out
conditions
S =πr =πr A
dN / dyS
2dN / dy20

2/ 3

Gluon saturation scale:QS ≈dN / dy≈ 1STAR
GeV
Experiment
2
πr

TC
Tch

✓Difference of Tch and Tkincorresponds to time
evolution of the system.

✓Kinematical & Chemical

<β>
200
400
dNch/dηYasuo MIAKE, 2010.07.07,Tsukuba

600

freeze-out show differencein centrality dependence!

➡Chem. freeze-out by T
➡Kin. freeze-out by what?
12

q

Yet, another Temp.

e+
e-

!*"

g

q

PHENIX P.R.L.104:132301(2010)✓Excess of electron
pair at low pt in AA
scaled by TAA for pT < 2.5 GeV/c, indicating that thedirect photon yield in the low pT range increases fasterthan the binary N N collision scaled p + p cross section.

n
T
TABLE I: Summary of the fits. The first and second errorsAe" p T /T+ Bp

are statistical and systematic, respectively.
centrality dN/dy(pT > 1GeV/c)
T (MeV)χ2 /DOF
0-20%
1.50 ± 0.23 ± 0.35
221 ± 19 ± 19
4.7/4
20-40%
0.65 ± 0.08 ± 0.15
217 ± 18 ± 16
5.0/3
Min. Bias
0.49 ± 0.05 ± 0.11
233 ± 14 ± 19
3.2/4

!

We fit an exponential plus the TAA -scaled p + p fit
function (Ae−pT /T + TAA × App (1 + p2T /b)−n ) to the
Au + Au data. The only free parameters in the fit are
A and the inverse slope T of the exponential term. The
systematic uncertainties in T are estimated by changing the p + p fit component and the Au + Au data
points within the systematic uncertainties. The resultsof the fits are summarized in Table I, where A is con-13✓Imply initial highYasuo MIAKE, 2010.07.07,Tsukuba

temperature !?

Fun
EPJ C46, 451 (2006

Thermal photons: Au+Au # !+X [0-10% central]
D.d’Enterria-D.Peressounko. T0 = 590 MeV, %0 =0.15 fm/cS.Rasanen et al. T0 = 580 MeV, %0 =0.17 fm/c

テキスト

D.K.Srivastava. T0 = 450--600 MeV, %0 =0.2 fm/c
S.Turbide et al. T0 = 370 MeV, %0=0.33 fm/c
J.Alam et al. T0 = 300 MeV, %0 =0.5 fm/c
PHENIX Au+Au [0-10% central]
Prompt !: NLO pQCD $ T AA [0-10%]
Yasuo MIAKE, 2010.07.07,Tsukuba

14

Re
pl ac
an tioe nLarge Elliptic Flow as a signature
Py

Z

Pz

Px
Y
X

y 2 − x2
�εecc = � 2
2y +x

p2y − p2xv2 = � 2
�2
py + px✓ In non-central collisions, participant region has almond shape.
➡azimuthal anisotropy in coordinate space✓ If λ<< R, azimuthal anisotropy of the coordinate space isconverted to that of the momentum space.

➡v2 ; second Fourier harmonics of azimuthal distribution✓ Goodies :N (φ ) = N 0 {1+ 2v1 cos(φ − Ψ0 ) + 2v 2 cos(2(φ − Ψ0 ))}• Clear origin of the signal• Collision geometry can be determined experimentally
Yasuo MIAKE, 2010.07.07,Tsukuba

15

Beautiful scalings of v2
PHENIX PRL 98(2007)162301

Au+Au 200 GeV✓mt scaling & quark number scaling hold!!
Yasuo MIAKE, 2010.07.07,Tsukuba

16

Universal scaling of v2?
By Maya Shimomura✓Systematics• Au+Au, Cu+Cu• 200, 62 GeV• Centrality• Pions, Kaons, protons✓45 curves scaled to
be one curve!

Yasuo MIAKE, 2010.07.07,Tsukuba

17

Puzzles in the mid-pt regionp/π enhances above 1.5 GeV/cv2 deviates from the mass ordering
above 2 GeV/c

Phenix; P.R.L. 91(2003)172301

y
l
a

m
o
n
A
n

o
y
ar

B

✓ In central col., p/π ratio is very large, while in peripheral, p/π ratio similar to
those in ee/pp suggesting fragmentaton process.


Fragmentation process should show np < nπ as seen in ee/pp.

✓ While mass ordering of v2 seen at low pt region, clear departure observed.
✓ Suggesting other production mechanism.
Yasuo MIAKE, 2010.07.07,TsukubaQuark Recombination Model(Quark Coalescence Model)

18

Quark Coalescence explains
Baryon Anomaly, and ...
✓ Quarks, anti-quarks combine to form

Hadronmesons and baryons from universal quark
distribution, w(pt).
Mom. distr. of meson (2q)；p
W M ( pt ) ≈ CM ⋅ w ( t 2 )2Mom. distr. of baryon (3q)；p
W B ( pt ) ≈ CB ⋅ w ( t 3 )3€w(pt)；

Universal
mom.
€
distr. of quarks｛steep in pt｝

QGP
Because of the steep distr. of w(pt), RECO
wins at high pt even w. small Cx.
Yasuo MIAKE, 2010.07.07,Tsukuba

Characteristic scaling features expected.
Quark Number Scaling (QNS)
19

also explains nq scaling !
✓Characteristic scaling behavior→Quark Number Scaling

HadronAzimutal distr. of meson (2q)；

dN M
2
2
∝ w = (1+ 2v 2,q cos2φ )dφ≈ (1+ 4v 2,q cos2φ )Azimuthal distr. of baryon (3q)；€

QGP

Azimuthal distr of quark; w€
Yasuo MIAKE, 2010.07.07,TsukubadN B∝ w 3 = (1+ 2v 2,q cos2φ ) 3dφ≈ (1+ 6v 2,q cos2φ )w ∝ (1+ 2v 2,q cos2φ )20

Adiabatic Expansion Model✓Intuitive Model✓Assuming,• Cylindrical expansion• Freeze-out condition
V (t) = ctπR(t)2 = ctπ(R0 + βT t)2
V (tfo )∼ R(tfo )knpart σ�R02 + 4 kσ
cπ βT npart − R0
tfo =
2βT

V0
1/3
T (tfo ) = T0 ()
tfo (R0 + βT tfo )2
Yasuo MIAKE, 2010.07.07,Tsukuba

1
λ=
∼R
nσ
• Adiabatic expansion
T 3 (t)V (t) = Const.
(∵ s ∝ T 3 )✓Larger fireballfreezees out laterin time21

Kinematical Freeze-out w.
Adiabatic Expansion
Adiabatic Expansion Model (M.Konno,Y.M. 2008)

Tch
Tkin

✓Adiabatic Expansion Model
explains centrality
dependence very well.
• Freeze-out conditions ; λ~R✓In central collsions, the F.B. is

tfo (A.U.)

Central collisions freeze-out late.

Yasuo MIAKE, 2010.07.07,Tsukuba

so large that F.O. occurs
later than peripheral.

➡Kinematical freeze-out iscollisional, while chemical isnot.
22Blast Wave Fitting of v2
and spectra
Adiabatic Expansion Model (M.Konno,Y.M. 2008)
By Masahiro Konno()*#+,#$%&"'Fitting pt range:
0.6-1.2 GeV/c for pi
0.4-1.4 GeV/c for K
0.6-1.7 GeV/c for p!"#"!"#$%&"'!"#$%$"&'()%*"+,&&-./"()!&0$)-1"""2(330-/"()40,*(5-1"0'6-./"',%!'7!&0$)-8"!"9()-*/":0$*%!6$5-";%".-*,0%*

✓pt distributions measured in plane andout-of plane are B.W. fitted independently
Yasuo MIAKE, 2010.07.07,Tsukuba

23

B.W. Fitting Results
Adiabatic Expansion Model (M.Konno,Y.M. 2008)

in-planeβT

By Masahiro Konno

Tfo

out-of plane✓T are the same in plane and out-of plane, while
βT(in-plane) > βT(out-of plane) !
Yasuo MIAKE, 2010.07.07,Tsukuba

24

Modulations wrt. theφRP
Adiabatic Expansion Model (M.Konno,Y.M. 2008)

Au+Au 200 GeV 20-30 %Tfo (φ) = 1 + 2T2 cos(φ − φRP )T2 = (-5.4 +/- 4.0) x 10-3

βT
β2

By Masahiro Konno

T2

Tfo

βT (φ) = 1 + 2β2 cos(φ − φRP )!2 = (3.3 +/- 0.2) x 10-2

✓T2 ≃ 0, while clear modulation in β.
✓Reaction Plane is determined independently.
Yasuo MIAKE, 2010.07.07,Tsukuba25

β２/ε is the constant !
Adiabatic Expansion (M.Konno,Y.M. 2008)

v２/ε

β２/ε

Tfo

✓β２/ε is the constant in Au+Au and Cu+Cu,
while v２/ε shows ˜ Npart1/3 .
➡Difference comes from the fact that v2 is sensitive to Tfo aswell. Strength of v2 is diluted if the Tfo is high.
➡Central collision shows lower Tfo because of the late freeze-out.
Yasuo MIAKE, 2010.07.07,Tsukuba

26

Soft
d
o

Statistical and
o

t
s

r
CollectiveeNaturedcharacteristic
to thenull
QGPformationew

Yasuo MIAKE, 2010.07.07,Tsukuba

27

Refer to the textbook !

Yasuo MIAKE, 2010.07.07,Tsukuba

28

Hard comp.
Partonic energy loss
Medium response
Tomography

Yasuo MIAKE, 2010.07.07,Tsukuba

29

Effects in Hard comp.
observed immediately✓For comparison, Au+Au & pp spectra
scaled by Nbinary.
Scaled pp
spectraCentral✓In peripheral
collisions,
Au+Au ˜ pp

✓In central collisions,
Peripheral

Au+Au < pp
 Suppression of yield ?
 Loss of pT ?

Yasuo MIAKE, 2010.07.07,Tsukuba

30

High pt suppression in AA
22David d’Enterria

80-92%
p-p " ! X @ 200 GeV # T AA
80-92%
NLO # T AA
[CTEQ6, KKP, µ =p -2p ]
T
T
i
0

-1

10

-2

10

103

10-3

10

0-10%

10-5
10-6

10

T

T

[W.Vogelsang]

10-3
10-4

10-6

-9

10-7

-10

10-8

10

0

i

10-2

10-8

10

[CTEQ6, KKP, µ =p -2p ]

10-1

10-5

-11

0-10%

NLO # T AA

1

10-7

10

p-p " !0 X @ 200 GeV # T AA

T

T

10-4

Au-Au " !0 X @ 200 GeV [0-10%]

2

T[W.Vogelsang]

1/[2! p ] d2N/dp dy (GeV/c)-2

Au-Au " !0 X @ 200 GeV [80-92%]

1T

1/[2! p ] d2N/dp dy (GeV/c)-2

Phenix; P.R.L. 91, 232301 (2008), PRD76,051106(2007)

Peripheral
2

4

6

8

10

10-9
12

14

16

18

20

p (GeV/c)T

0Central
2

4

6

8

10

12

14

16

18

20

p (GeV/c)T

Fig. 15. Invariant !0 yields measured by PHENIX in peripheral (left) and central (right)
AuAu collisions (squares) [89], compared to the (TAA -scaled) pp → !0 + X cross section (circles) [134] and to a NLO pQCD calculation (curves and yellow band) [119].

✓Clear and similar suppression up to ˜20 GeV/c
Yasuo MIAKE, 2010.07.07,Tsukuba

31Suppression of high pt
particles
10-8

10-6

10-9

10-7

-10

10-8

-11

10-9

10

10

0

4

6

8

10

12

RAA

Cronin effect

1

0.34

16

18

20

0

2

4

6

8

10

12

14

16

18

p (GeV

T

T

Fig. 15. Invariant!0 yieldsQCDmedium”
measured by PHENIX in peripheral(left)and central (rig”hot/dense
dnAA /dp
T dy
RAAcollisions==AA -scaled) pp → !0 + X cross section (AuAu(squares) [89], compared to the (T”QCD vacuum”
�Nbinary � · dnpp /dpT dycles) [134] and to a NLO pQCD calculation (curves and yellowband) [119].
Au+Au - 200 GeV (central collisions):
Direct $ , $ * [PHENIX]
Inclusive h± [STAR]!0 [PHENIX]% [PHENIX]g
GLV energy loss (dN /dy = 1400)

10

binary collisionscaling

Ncoll scaling

1

participant scalingpT

14

p (GeV/c)

RAA

NuclearModification
Factor2-1

10

Npart scaling

0

2

4

6

8

10

12

14

16
18
20
p (GeV/c)directphotons
arenot✓Pions are suppressed,
Fig. 16. R (p ) measured in central AuAu at 200 GeV for ! [89] and % [135] meso
T

AA

0

T

hadrons[114], anddirect photons
with
Npart
scaling!?[136, 137] compared to theoretical predictions• Accidentalcharged
parton energy loss in a dense medium with dN /dy = 1400 (yellow curve) [138].

Yasuo MIAKE, 2010.07.07,Tsukubag32

Au+Au vs d+Au
Phenix; P.R.L. 91, 072303 (2003)

Au+Au at sNN = 200 GeV

d+Au→h +X at sNN = 200 GeV✓High pt suppression in Au+Au, while notobserved in d+Au.
Yasuo MIAKE, 2010.07.07,Tsukuba➡Effect is not due to initial state, but final state.

33

Npart & Nbinary✓Npart;• # of participant nucleons• Particle production in hA is

Participant

prop. to Npart, (WoundedNucleon Model)
Au+Au collisions✓Nbinary;• # of binary nucleon-nucleon
collisions• Pass through at high energy.
• Evaluation of Npart & Nbinary
by Glauber Model.
Yasuo MIAKE, 2010.07.07,Tsukuba

34

Npart scaling?

RAPID COMMUNICATIONSPHYSICAL REVIEW C 67, 061901$R% $2003%

Phys. Rev. C 67,061902(2003)
Q(pT)✓Rate of initial hard

0.25

scattering should be
prop. to Nbinary.

0.2

0.1

✓Npart scaling may be due

BDMS
BH
RW

0.15

6

8

10

12

14

16

pT

FIG. 2. Dependence of the quenching factor Q on p T for central
collisions. The parameter ( is chosen such that Q(p T )00.2 forp T !10 GeV/c in each case. The scaling laws $BH, RW% exhibit
stronger quenching with increasing p T , in agreement with preliminary RHIC data, in contrast to the BDMS law. Equation $5% provides a good description of the dependence on p T seen here.

etry is not axially symmetric. This is known to lead to anangular asymmetry of a quadrupole shape in the spectra of
Yasuo
2010.07.07,Tsukuba
high-pMIAKE,
particles#23,24&. The elliptic flow parameter v is

to surface emission ofparticles;➡strong quenching limit✓Need LHC data !!
35

Jet quenching3“Jet Quench”-perturbatively into a set of final-state hadrons. The characteristic colliray of hadrons resulting from the fragmentation of an outgoing parton isjet”.

✓Two quarks suffer aIV.2 Perspective view of the DCal and PHOS integrated on a common support. As
discussed in the text, the support structure is a component of the full international project
scope. Five PHOS modules are shown although only three, those contiguous with theproposed DCal, are installed in ALICE at the moment and considered part of DCal.

hard scattering in AA
collision
28• One goes out to vacuum

creating jet,
• but the other goes
through the QGP
suffering energy loss due
to gluon✓Manifestation:
attenuation/•quenching” in a head-on nucleus-nucleus collision. Two quarks suffer a hard scat-“Jet quenching” in nucleusnucleus collision.
•of jetgoes out directly to the vacuum, radiates a few gluons and hadronises,disappearance
the othergh the dense plasma created (characterised by transport coefficient q̂, gluon
density
suppression
of
high
pt
nd temperature T ), suffers energy loss due to medium-induced gluonstrahlung andhadrons
ments outside into a (quenched) jet.
Yasuo MIAKE, 2010.07.07,Tsukuba• modification of jet frag.

36

near side

Modification of
back-to-back corr.

Star; P.R.L. 91, 72304 (2003)
away side
pTtrig = 4˜6 GeV/cpTassoc > 2 GeV/cpedestal and flow
subtracted

Yasuo MIAKE, 2010.07.07,Tsukuba✓Direct evidence ofloss of ʻjetʼ✓Azimuthal
correlation w.r.t. highpt leading particle(trigger).
pp ; clean di-jetdAu; similar to pp



Au+Au; Similar on thesame side (suggesting
jet-like mechanism), but bto-b disappeared Effect is not in initial
but in final stage
 Energy loss of partonsin dense mattercreated in Au+Au

37

ergy losses in QEDEnergy loss in QED

an illustrative example, we show in Fig. 4 the stopping power of muons in copAt low and high energies, the collisional (aka “Bethe-Bloch”) and the radiativergy losses dominate respectively.

Stopping power [MeV cm2/g]

Energy loss of charged particle in a matter

Collisional✓Bethe-Bloch
Bremsstrahlungµ+ on Cuµ(

10LindhardScharff

100

Bethe-BlochRadiative✓Bethe-Heitler(thin; L<<λ)✓LandauPomeranchukMigdal(thick; L>>λ)Radiative

AndersonZiegler

Eµc
Minimum
ionization

NuclearlossesRadiative
lossesRadiative
effects
reach 1%

Without %
1
0.001

0.01

0.1

1

10

0.1

1

10

100

1

[MeV/c]

&'

100

1000

10 4

10 5

10 6

10

100

1

10

100

[GeV/c]Muon momentum[TeV/c]✓

4. Stopping
power, −dE/dl, for positivein coppergives
as a functionof &' = p/Mc
Measurements
ofmuonsdE/dx
prop.
of (ormattermentum p). The solid curve indicates the total stopping power [15].

• Energy loss in QED plasma gives T & mD info.

Yasuo MIAKE, 2010.07.07,Tsukuba

38

the particle per unit-time (related to the transport coefficient as ( ≈ q̂ v) – and"byg &gg ) # 0.45 fm (the quark mean-free-path ismomentum drag coefficient )D .
/Cthe
F = 9/4 is the ratio of gluon-to-quark colouris therefore q̂ # m2D /'g # 2.2 GeV2 /fm. Notebeenobtained witha LO expression
in loss!s forMechanisms
of in-medium
energyHigher-order scatterings (often encoded in a
ault
generalway,
the values
total energy
in muchlargerof q̂. loss of a particle traversing a medium is the sum of
4 : *E = *Elisionalthe
anddynamics
radiativeofterms
erisingheavy
non-relativisticcoll + *Erad . Depending on the kinematic
5ion, a (colour)chargelose energy
a plasma with temperature T mainly byaversing
the plasma,is canconnected,
via theinEin6
o mechanisms .
T 2 /( = T /(M )D )(3)

Energy Loss in QCD

E-!E
ent ( – theEaverage momentum
squared gained
ed to the transport coefficient as ( ≈ q̂ v) – andE.
!E

gy loss

Collisional

!E
E-!E

of a particle traversing a medium is the sum ofX= *Ecoll + *Erad . Depending on the kinematic (medium)rgy5 in a plasma with temperature T mainly by. 3. Diagrams for collisional (left) and radiative (right) energy losses of a quark of energy
raversing a quark-gluon medium.

E!E

Collisional energy loss through elastic scatterings with the medium constituents(Fig. 3, left) dominates at low particle momentum. The average energy loss inRadiative

E-!E by powers of ! c # 0.2 GeV fm (other useful equalities:
For unit conversion, multiply
10 mb = 1 fm2 , and 1 GeV−2 = 0.389 mb).
X
In addition, synchrotron-,Čerenkov- and transition-radiation energy losses can take place(medium)
respectively if the particle interacts with the medium magnetic field, if its velocity is greaterthan the local phase velocity of light, or if it crosses suddenly from one medium to another.
radiative (right) energy losses of a quark of energy
Also, plasma instabilities may lead to energy losses. Yet, those effects – studied e.g. in [11,12, 13, 14] for QCD plasmas – are generally less important in terms of the amount of Eloss .
Note that if the energy of the particle is similar to the plasma temperature, E ∼ O(T ), theparticle can also gain energy while traversing it.
asticthatscatterings
with themediumconstituentsNotethe separation
is notso clear-cut
since the diagrams assume well-defined asymprticle
momentum.
Theoutgoingaverageparticles
energymay
lossstillin be in the medium and further rescatter.
totic outstates, but the✓Many theories on• Collisional loss
• Radiative loss

wers of ! c # 0.2 GeV fm (other useful equalities:mb).
nd transition-radiation energy losses can take placeh the medium magnetic field, if its velocity is greaterr if it crosses suddenly from one medium to another.
nergy losses. Yet, those effects – studied e.g. in [11,erally less important in terms of the amount of Eloss .
s similar to the plasma temperature, E ∼ O(T ), theversing it.
cut since the diagrams assume well-defined asympes Yasuo
may stillMIAKE,
be in the medium
and further rescatter.
2010.07.07,Tsukuba➡Bethe-Heitler regime➡LPM regime➡“dead-cone”effect∆E ∝ αS CR �q̂�L2(Executive) Summary
Radiative loss is dominantEﬀects are;•suppression of high pt hadron•unbalanced back-to back•modiﬁcation of jet fragmentation
softer, larger multiplicity,
angular broadening∆Egluon > ∆Equark > ∆Echarm > ∆Ebottom 39

Intuitive analysis ofenergy loss of parton
In pp collisions,

3

d n
E 3
dp

d 3n
dn
A
E 3=
= n with n = 8.1
dp
2"pT dpT dy pT
In Au + Au collisions, fraction of pT loss; Sloss
pT# = (1$ Sloss ) pT

−8.1
pT

dn
dn dpTA
1
A(1$ Sloss )
=
= n$1
=
n$1
#
#
#
dpT dpT dpT pT (1$ Sloss )pT

n$2

A(1$ Sloss ) n$2 pT#n$1
n$2
RAA =
= (1$ Sloss )
n
A pT

pT
Yasuo MIAKE, 2010.07.07,Tsukuba

1% Sloss = 1$ RAAn$2✓Energy loss ˜ 0.2 @ RHIC

40

asymmetry of the system produced in non-central nuclear collisions (Fig. 21, left).
Partons produced “in plane” (“out-of-plane”) i.e. along the short (long) direction of
the ellipsoid matter with eccentricity " will comparatively traverse a shorter (longer)
thickness.

L-dependence of
suppression

ε lossPhenix; P.R.L. 76, 034904 (2007)

0.25

5 < pT < 8 GeV/c

0.2
0.15
0.1
0.05
0
-0.05
0

1

2

3

4

5

L# (fm)6

Fig. 21. Left: Effective thicknesses along various azimuthal directions with respect to theof suppression
on reaction
plane
angleloss "loss✓Dependence
reactionplane in the overlap
region of two heavy-ions.
Right: Fractionof energy
versus effective path-length L" measured for high-pT neutral pions in AuAu at 200 GeV [142].

✓Assume Glauber Model w. Wood-saxon

Yasuo MIAKE, 2010.07.07,Tsukuba

41

dimensions of the ellipse, the above analysis ignores
the dependence of participant density on position in
the transverse plane. Thus as a natural extension of thesimple length scale in (i), for another analysis of thedependence of energy loss on !φ, we assume that thecolor-charge density in the medium is proportional toparticipant density (see Refs. [29,59]) and evaluate ρL,
the integral of this density along the path length of theparticle. This quantity is proportional to the opacity ofthe medium (n = L/λ) divided by some undetermined0

To account for the possible role of LPM coherence inthe energy loss process, we evaluate a similar quantity,
including an extra factor of r in the integrand.
! ∞
2
ρL =
dr rρpart (r, !φ).
(19)

Universal Behavior
0

We note that a Bjorken 1/τ expansion of the medium
would approximately cancel one power of r in the aboveThen,ρL, might represent LPM energy
Phenix; P.R.L. 76, expressions.
034904(2007)

1.4

0.25

3 < pT < 5 GeV/c✓RAA and Sloss

3 < pT < 5 GeV/c

are universal asa function ofpath length L

1.2

0.2
1

0.15

Sloss

RAA

0.8
0.6

0.05

0.4

0

0.2
0
0

0.5

1

1.5

2

L∈ (fm)

1.4

2.5

3

3.5

4

5 < pT < 8 GeV/c

1.2

Sloss

RAA

-0.05
0

1

0.25

5 < pT < 8 GeV/c2

3L∈ (fm)

4

5

6

0.8
0.6

• all centrality• all pT range✓No suppresion

0.2

1

0.15

for L < 2 fm

0.1
0.05

0.4

0

0.2
0
0

0.1

-0.05
0.5

1

1.5

2

L∈ (fm)2.5

Yasuo MIAKE, 2010.07.07,Tsukuba

3

3.5

4

0

1

2

3

L∈ (fm)

4

5

6

42

studied in detail in [89, 143] taking into account the experimental (though not th
retical) uncertainties. The PHENIX !0 suppression data allows
one
toconstrain23+2.1 Jet quenching+6.3
transport coefficient of the PQM model [78] "q̂# as 13.2 −3.2 and −5.2 GeV2 /fm aT ≈ 0.4 GeV [72]. The quality of agreement between the theory and data has been
one and two standard-deviation(Fig.
right).the experimental (though not theostudied in detail levels
in [89, 143]
taking17,
into accountHigh pt supp. w PQM model

retical) uncertainties.
allows one to constrain the+2.1 The PHENIX
6.3 !0 suppression
2 data+2.1
2transport coefficientmodel [78] "q̂# as 13.2 −3.2 and +6.3
−5.2
−3.2 of the PQM−5.2 GeV /fm at theone and two standard-deviation levels (Fig. 17, right).

andGeV /fm

%
$
2

2

1
1
PHENIX !0 (Au+Au
0-5% Central)

$%

RAA

RAA

q̂ = 13.2

PHENIX !0 (Au+Au
0-5% Central)
Global Systematic Uncertainty± 12%

Global Systematic Uncertainty ± 12%

30
30

25

25
20

10-10

2

4

6

8

10 12 14 16 18 20
p (GeV/c)

0

5

10

15

20

25

PQM Model # q " (GeV2/fm)

T

20

10-10

2

4

6

Fig. 17. Left: RAA (pT ) for neutral pions in central AuAu collisions (triangles) [89] compared to PQM predictions [78] for varying values of the q̂ coefficient (red curve, best fit
for "q̂# = 13.2 GeV2 /fm). Right: Corresponding (data vs. theory) $2 values for the PQM q̂
8
10 12 14 16 18 20
0
5
10
15
20
parameters that fit the data points on the left plot [143].

p (GeV/c)T

Yasuo MIAKE, 2010.07.07,Tsukuba

2

PQM Model # q " (GeV

The consistency between the extracted q̂, dN g /dy and T values in the various

43Phenomenological quench w.
hydrodynamical expansion

the ASW, AMY and HT schemes are shown in Table 1. The ASW calculations consistently predict a higher q̂ than AMY or HT. Seemingly, as of today, comparisons ofmodel predictions to RHIC results for RAA (pT ) can only constrain q̂ within a factorof 2 – 3. The origin of such a large variability can be traced to a combination of(i) the relative insensitivity of using just a single-inclusive observable28, RAA (pT ),in the data–model comparisons [91] (additional independent measurements placeextra constraints on q̂ as discussed in Section 5.1), and (ii) the assumptions about
the equation-of-state of the medium (and its time evolution) and the correspond2
ing approximations relating its thermodynamical and ∆Etransport
properties.
Genuine∝ αS CR �q̂�Lmodel differences (e.g. AMY accounts for collisional loses which are neglected in
the purely radiative ASW approach) play also a role. A working group [146] hasbeen recently created to clarify discrepancies among the formalisms.

+

See arXiv:0902.2011 for references

Table 1. Transport coefficients q̂ derived in a 3-D hydro simulation of an expanding QGP withinitial temperature T0 = 0.4 GeV (at "0 = 0.6 fm/c) [145] with different parton energy loss
implementations (ASW, HT and AMY schemes) that reproduce the high-pT $0 suppression
observed in central AuAu at RHIC [89]. The a, b exponents indicate two choices of scaling ofq̂(r, ") with the initial plasma temperature or energy-density: (a) q̂0 % T03 (r, "), and (b) q̂0 %
3/4&0 (r, "). The PQM/ASW result (Fig. 17, !q̂" for a static plasma) is also listed for comparison.

q̂ (GeV2 /fm)
Yasuo MIAKE, 2010.07.07,Tsukuba

ASW

HT

AMY

10(a) – 18.5(b) , 13.2(PQM)

2.3(a) – 4.3(b)4.1(a)
44

coupled medium. In this model the azimuthal anisotropy
is only due to the path length dependence of energy loss,
and the data clearly favor larger vHF
2 than predicted fromthis effect alone.

Heavy Flavor, c & b
PHENIX PRL 98(2007)172301

RAA

1.8
1.6

(a)

0-10% central✓Electrons fromArmesto et al. (I)1.4

van Hees et al. (II)1.2



Heavy Flavor
decay (charm,bottom)✓HF suffers similarenergy loss

3/(2πT) Moore &12/(2πT) Teaney (III)

1
0.8
0.6
0.4

vHF
2

0.2

(I) q̂ = 14 GeV /fm
2

Au+Au @ sNN = 200 GeV

0.2

(b)

0.15

✓Large v2HF

π 0 RAA
π 0 v 2, p > 2 GeV/c

minimum bias

indicates charm
flows

T

e± RAA , e± vHF
2

0.1
0.05

➡Heavy quarks are

0

0

1

2

Yasuo MIAKE, 2010.07.07,Tsukuba

3

4

5

6

7

8

9

pT [GeV/c]coupled to themedium45

Should we
study
Jet Quench
inJets?
Yasuo MIAKE, 2010.07.07,Tsukuba

46Jet - hadron correlation
High Tower Trigger (HT) : (ηxφ)=(0.05x0.05) ET>5.4GeV

RHIC-AGSʼ09, J. Putschke✓On away side, less high pt particles,
while more low pt particles✓No mach cone structure !?
Yasuo MIAKE, 2010.07.07,Tsukuba

47

Jet - hadron corr.

✓Study of “jet quenching”in terms of the energy flow
Yasuo MIAKE, 2010.07.07,Tsukuba

48

Jet analysis ˜ cone radius✓Effects are energy loss and broadening !!
✓Narrow cone may be another control variable➡We like to extend and bring up to a precision meas.
Yasuo MIAKE, 2010.07.07,Tsukuba

49

Now, LHC

Yasuo MIAKE, 2010.07.07,Tsukuba

50

View from RHICians✓Nothing much changes
RHIC

LHC

from RHIC to LHC.

√ sNN (GeV)

200

5500

• Nevertheless,

T/Tc

1.9

3.0-4.2ε(GeV/fm3)

5

15-60

τQGP (fm/c)

2-4

>10

Yasuo MIAKE, 2010.07.07,Tsukuba➡Larger/longer QGP➡Nice to confirm RHIC results✓Moreover, higher
energy jets become
available!

51

Chances are at LHC✓Many orders ofmagnitude!

✓Jet Quench as afunction of,• jet energy• path length,
reaction plane angle• quark/gluon diff.

✓From particle ID toparton ID !!
Yasuo MIAKE, 2010.07.07,Tsukuba52dominated by quark (gluon) scatterings. A full NLO calcu
predicts that hadrons with pT ≈ 5 GeV/c at SPS (LHC)
duced by quarks (gluons), whereas at RHIC they come 50
RAA (p = 4 GeV/c)parton ! hadron+X at pT = 5 GeV/c :1gluonsquarks

0.9
0.8

1
0.7
0.5

T

relative parton (q,g) contribution

More gluons !!

0.7
0.6
0.5

SPS

RHIC

LHC

0.4

0.3
0.2
0.1

Energ

0.3

Energ

0.2
0.1
0

10

NLO pQCD, KKP FF [W.Vogelsang]

0.01

102

103

s (GeV)

Fig. 22. Left: Relative fraction of√quarks and gluons fragmenting

Yasuo MIAKE, 2010.07.07,Tsukuba

53How we study
Jet quench
at LHC
Meas. of high pt
suppression/
Hadron corr.
↓
Full back-to back jet
analysis of higher
energy jets
Yasuo MIAKE, 2010.07.07,Tsukuba

54

Probes for the study
γ-Jet

Di-jet✓Quark Jet✓Mostly Gluon Jet✓Small Xsection ✓Larger Xsection✓Experimentally ✓Interpretation
challenging

is complicatedπ0-Jet0 trigCleanπ✓✓Large Xsection✓Important for
DCal

Systematic meas. of these processes for modelcomparison provides at high precision level.
Yasuo MIAKE, 2010.07.07,Tsukuba

55

DCal as an extension of
EM-Cal✓For better performanceof back-to back capability➡Define back-to back jets
➡Trigger back-to back jets

ALICE EMCAL✓Progress• Proposed in Feb.,09• Discussed w. IN2P3 in May,

Extension proposed

DiJet Calorimeter
Yasuo MIAKE, 2010.07.07,Tsukuba

09• Discussed in March,09• Proposal in May, 09• Partial approval in July, 09• Full approval by ALICE in
Oct. 09✓Construction started !
56

EMC-2

Beam View

EMC-1

EMC-3

✓5 contiguous
6

modules possible,
while exact backto-back is 3

g
e
d
0

EMC-5

g
e
d
60
JCal-3JCal-1

Yasuo MIAKE, 2010.07.07,Tsukuba

JCal-2

57

G
00
~1

~2

00

G

eV

eV

What we expect;
Reach of Jet Energy✓For 104 events/year in Pb+Pb@5.5TeV,• Inclusive jet up to 200 GeV• Di-Jet to 100 GeV

Yasuo MIAKE, 2010.07.07,Tsukuba

58

E1JET

What we expect;sensitivity!

E1JET − E2JETBalance ≡1/2(E1JET + E2JET )E2JEThing” in a head-on nucleus-nucleus collision. Two quarks suffer a hard scatout directly to the vacuum, radiates a few gluons and hadronises, the otherdense plasma created (characterised by transport coefficient q̂, gluon density
erature T ), suffers energy loss due to medium-induced gluonstrahlung andoutside into a (quenched) jet.

Figure II.7 Distribution of di-jet energy balance ! for quenche(qhat = 50 GeV2/fm), for DCal jet energy threshold of 100 GeVbars show the statistical precision of the signal for 0.5 nb-1 offirst proposed “smoking guns” of QGP formation was “jet quenchattenuation or disappearance of the spray of hadrons resulting fromon of a parton having suffered energy loss in the dense plasma proction (Fig. 2). The energy lost by a particle in a medium, !E, protal information on its properties. In a general way, !E depends both
istics of the particle traversing it (energy E, mass m, and charge) androperties (temperature T , particle-medium interaction coupling1 ",), i.e. !E(E, m, T, ", L). The following (closely related) variables are
l to characterise the interactions of a particle inside a medium:ee path # = 1/($%), where $ is the medium density ($ & T 3 for an
nd % the integrated cross section of the particle-medium interaction2,
N = L/# or number of scatterings experienced by the particle in ahickness L,
ass mD (T ) ∼ g T (where g is the coupling parameter) is the inverse ofg length of the (chromo)electric fields in the plasma. mD characterises
Yasuo MIAKE, 2010.07.07,Tsukuba

Pb+Pb (0-10% central collisions). Solid line represents a fit totruncated Gaussian function.
!
!
!
!

✓ Sensitiv
ity indata of1 year!

59

Assembled in Japan/
Italy

E DCal Proposal Revision 0.0

DCal assembly
APD tested in Italy

Assembled in Grenoble/
NantesMarch 2010

Installed at CERN

Perspective view of the DCal and PHOS integrated on a common support. As
Yasuo
MIAKE,
ussedin the text,
the support 2010.07.07,Tsukuba
structure is a component of the full international project

Tested in Nantes

60Summary✓10 years of RHIC running was very successful✓QGP formation and time evolution of thereaction well understood (personal bias!)• Need quantitative understanding of QGP phase✓Next steps are,
• Discover phase transition point by lower energy
scanning at RHIC

• Quantitative study of QGP property using jet as aprobe at LHC
Yasuo MIAKE, 2010.07.07,Tsukuba

61

Backups
Yasuo MIAKE, 2010.07.07,Tsukuba

62

near side

Shape change ofaway-side
away side

pTtrig = 3˜4 GeV/cpTassoc
PHENIX, arXiv:0705.3238 [nucl-ex]

e
d
i
-s

y
a
w

s
s
Lo

a
f
o

✓From broad/none to distinct two shoulders
at ΔΦ＝πYasuo MIAKE, 2010.07.07,Tsukuba

1 with decreasing momentum.

63

Shoulders at ΔΦ＝π

1 !?

PHENIX, arXiv:0705.3238 [nucl-ex]✓Location & <pt> of shoulder seem to be independentof centrality and pt.
➡If confirmed, Shock Wave / Mach Cone !
✓Effect is very fragile, sensitive to mom. range and
ZYAM correction
Yasuo MIAKE, 2010.07.07,Tsukuba

64