Physics with DCal in ALICE

Tatsuya Chujo
University of Tsukuba(for the ALICE DCal Project)
Symposium on Jet Physics at RHIC and LHC, Hangzhou, China,
July 21, 2011 (T. Chujo)

由于ALICE DCal 的喷射物理的研究

中條 達也
筑波大学
Symposium on Jet Physics at RHIC and LHC, Hangzhou, China,
July 21, 2011 (T. Chujo)

Before	  my	
  talk…	
  A	
  short	  history;	
  Rela4onship	
  between	
  Hangzhou	
  and	  Japan	Hangzhou
杭州~1000 km

Hakata博多

南宋2代皇帝 孝宗
Emperor Xiaozong(1127-1194)
•
•
•
•
•

平清盛
General Taira no Kiyomori(1118-1181)

Hangzhou 杭州：Capital of Song dynasty (Southern Song 1127-1279).
There is a trade between Song Dy. and Japan (Hakata) in 10-13 cent, 日宋貿易
From Song: Cupper Coin, Silk, Chinaware, Book, Canon of Buddhism, etc.
From Japan: Gold, Silver, Sulfur, Pearl, Handcrafts, etc.
Big impact on development of Japanese economy at that time!
3

Symposium on Jet Physics at RHIC and LHC, Hangzhou, China,
July 21, 2011 (T. Chujo)

Outline	
1. Introduc/on	
  – Parton	  energy	
  loss	  &	
  jet	
  quenching	  – First	  results	
  on	
  jet	
  quenching	
  at	
  LHC	
  2. Dijet	
  Calorimeter	  (=DCal)	
  in	
  LHC-­‐ALICE	  3. Physics	
  cases	
  for	
  DCal	  4. Current	
  stats	
  and	
  plan	  5. Summary	  Symposium on Jet Physics at RHIC and LHC, Hangzhou, China,
July 21, 2011 (T. Chujo)

4

1.	
  Introduc/on:	  Parton	  Energy	
  Loss	• A?er	  the	  discovery	
  of	
  
QGP	
  at	
  RHIC,	
  we	
  are	  now	  interested	
  in	
  the	
  proper4es	
  of	
  QGP	  in	
  detail.	
  • From	  discoveries	
  to	
  precision	
  measurements.	
  • Energy	
  loss	
  of	
  parton	
  
(ΔE)	
  in	
  hot	
  and	
  dense	  medium	  has	  a	
  rich	  and	  key	
  contents	
  to	
  iden4fy	
  the	
  QGP	
  proper4es.	
Symposium on Jet Physics at RHIC and LHC, Hangzhou, China,
July 21, 2011 (T. Chujo)

5Analogy:	
  dE/dx	
  in	
  QED	Can we understand dE/dx of parton in QGP like this?
Symposium on Jet Physics at RHIC and LHC, Hangzhou, China,
July 21, 2011 (T. Chujo)

6Ingredients	
  of	
  parton	  energy	
  loss	  in	
  hot/dense	
  maQer	Figures taken from Christof Roland’s talk (QM11)(a) Radiative energy
loss in medium(b) Collisional energy
loss in medium(c) Fragmentation (invacuum, or medium
modified), and jets.

• These ingredients are sensitive to medium properties, and location andtime of the process happens.
• Direct jet reconstruction à a crucial role to determine the medium
properties.
Symposium on Jet Physics at RHIC and LHC, Hangzhou, China,
July 21, 2011 (T. Chujo)

7Direct	
  jet	
  quenching	
  is	
  seen	
  at	
  LHC!	

Symposium on Jet Physics at RHIC and LHC, Hangzhou, China,
July 21, 2011 (T. Chujo)

8

AJ:	
  di-­‐jet	
  asymmetry	
  ATLAS R=0.4

pT ,1 ! pT ,2
AJ =
pT ,1 + pT ,2

CMS R=0.5• Quantify jet energy imbalance by the asymmetry ratio.
• Large asymmetry is seen in energy imbalance.
Symposium on Jet Physics at RHIC and LHC, Hangzhou, China,
July 21, 2011 (T. Chujo)

Highlights	
  on	
  jets	
  at	
  LHC	
  (QM2011)	
  	
  	
1. Extremely	
  large	
  energy	
  loss	
  on	
  the	
  away	  side	  jets.	
  – Large	
  energy	
  asymmetry	
  in	
  central	
  Pb+Pb.	
  – Jet	
  Rcp	  ~	
  0.5.	
  
2. LiVle	  modiﬁca4on	
  of	
  jet	
  shape	  	
  – both	  near	  and	
  away	  side.	
  	
  – Both	  transverse	
  (jT)	
  and	
  longitudinal	
  (FF).	
  – No	
  broadening	
  of	
  jets.	
  AJ

3. Lost	  energy	
  is	
  used	  for	  the	
  low	  pT	  bulk	  par/cle	
  produc/on	
  at	
  large	
  angle!	
  Symposium on Jet Physics at RHIC and LHC, Hangzhou, China,
July 21, 2011 (T. Chujo)

10What’s	
  next?	
• One	
  has	  to	
  study	  this	  very	  interes4ng	
  phenomena	
  in	
  great	  detail	
  from	
  many	  aspects.	
  • (personally)	
  Interested	
  in	
  the	
  medium	
  response	
  (so?	
  par4cle	
  produc4on)	
  by	
  the	
  passage	
  of	
  energe4c	
  parton	
  and	
  its	
  energy	
  loss.	
  – Re-­‐heated	
  maVer?	
  – If	
  so,	
  what	  the	
  mechanism	
  of	
  re-­‐hea4ng?	
  
– …	
  	
  
In	
  order	
  to	
  answer	
  this	  ques/on:	
  “Jet	
  axis”	
  is	
  one	  of	
  the	
  key	  parameters.	
  Then,	  measure	
  the	
  other	  observables	
  surrounding	
  the	
  jet	
  jet	
  axis,	  including	
  so?	  par4cles.	
  – Par4cle	
  composi4on	
  of	
  bulk	
  so?	  par4cles	
  produced	
  by	
  jets.	
  – Reac4on	
  plane	  dependence	
  of	
  jet	
  proper4es	
  (path	  length	
  eﬀect).	
  • ALICE	  has	  an	
  advantage	
  of	
  this	  kind	  of	
  analysis.	
  
	
  	
  	
  	
  	
  	
  	
  	
  	
  	
  	
  	
  	
  
Symposium on Jet Physics at RHIC and LHC, Hangzhou, China,
July 21, 2011 (T. Chujo)

11

2.	
  DIJET	  CALORIMETER	  (=DCAL)	
  IN	
  LHC-­‐ALICE	
  Symposium on Jet Physics at RHIC and LHC, Hangzhou, China,
July 21, 2011 (T. Chujo)

12

ALICE	  experiment	
  	
  	
  	
  	
  	
  	
  	
  	
  
ALICE	  =	  A	  Large	  Ion	  Collider	
  Experiment	  •Dedicated	
  heavy	
  ion	
  experiment	
  at	
  LHC:	
  	
  
	
  

Symposium on Jet Physics at RHIC and LHC, Hangzhou, China,
July 21, 2011 (T. Chujo)

13

Key	
  detectors	
  for	
  jet	
  measurement	
  in	
  ALICE	
•

•

•

TPC	
  (+ITS)	
  – Charged	
  par/cles	
  Δη	
  =	
  1.8.	
  – Excellent	
  momentum	
  resolu4on.	
  – Excellent	  PID	
  and	
  heavy	
  ﬂavor	  tagging.	
  EMCal	
  – Pb-­‐Scint	  sampling	
  EMC.	
  
– Δφ	
  =	
  107°,	
  Δη	  =	
  1.4	  – Energy	  resolu/on	
  ~10%/√Eγ	

– Jet	
  and	  γ	  trigger	
  
PHOS	
  
– PWO	
  crystal	  EMC.	
  – 220°	
  <	
  φ	
  <	
  320°,	
  Δη	  =	
  0.24	  – Energy	  resolu/on	
  ~3%//√Eγ	

– γ trigger.	
  

TPC

EMCal
PHOS

Symposium on Jet Physics at RHIC and LHC, Hangzhou, China,
July 21, 2011 (T. Chujo)

14Fluctua/on	
  by	
  neutral	
  Charged(2/3)~15@100Gev

EJET
Neutral(1/3)~7@100Gev

EJET=ECHARGED+ENEUTRAL
dECHARGED = -dENEUTRAL• Current jet identification in ALICE is limited, due to the limited
acceptance of EMCal; neutral component does matter.
• Statistical fluctuation with total energy limitation.
– Total jet energy is fixed.
• fluctuation of neutral play significant role
• Need larger acceptance EMC on opposite side of EMCal in
15
ALICE.
Symposium on Jet Physics at RHIC and LHC, Hangzhou, China,
July 21, 2011 (T. Chujo)

ALICE	
  Dijet	  Calorimeter	
  (DCal)	
•Extension of the acceptance of
EMCal .

•

Lead-scintillator sampling type EMC
with APD readout.
– EMCal: Δφ = 110°
– DCal: Δφ = 60° (on opposite sideof EMCal)– Δη = 0.7 for both EMCal and DCal

+ PHOS– ~10%/√E•
DCal

Allow back-to-back hadron-jet, di-jet
measurements in ALICE, with R =0.4, up to pT ~ 150 GeV/c.

PHOS

•

Enhance jet, γ trigger capability.

Symposium on Jet Physics at RHIC and LHC, Hangzhou, China,
July 21, 2011 (T. Chujo)

16

D-Cal Design
DCal – 6 supermodulesΔη~0.74
3
2

PHOS – 5 modulesshown
6 Super Module configuration was chosen to have alargest possible jet radii in DCal, together with PHOS,
i.e. R=0.4
Workshop for ALICE upgrades by Asian countries, Yonsei Univ. Seoul, Nov. 6, 2009 (T. Chujo)

17

ALICE-DCal Collaboration
China
Huazhong Normal University (CCNU), Wuhan
Finland
University of Jyvaskyla
FranceLPSC Grenoble, Subatech Nantes, IPHC Strasbourg
Italy
INFN Catania, LNF Frascati,
Japan
Hiroshima University, University of Tokyo, University of Tsukuba,
Switzerland
CERN
USA
Lawrence Berkeley National Laboratory, Wayne State University, University of
Houston, University of Tennessee, Lawrence Livermore National Laboratory,
Yale University, Oak Ridge National Laboratory, Creighton University, Cal PolySan Luis Obispo, Purdue University
Workshop for ALICE upgrades by Asian countries, Yonsei Univ. Seoul, Nov. 6, 2009 (T. Chujo)

18

3.Physics	
  case	  of	
  DCal	• Case1:	
  Jet-­‐Jet	
  in	
  p+p	  • Case2:	
  Jet-­‐Jet	
  in	
  Pb+Pb	
  (quenching	  eﬀect)	
  • Case3:	
  π0-­‐Jet	
  in	
  Pb+Pb	  – Notes:	
  • MC	
  simula4on	
  study	  using	
  qPYTHIA.	
  • “DCal”	  means	  including	
  PHOS	
  acceptance,	
  i.e.	
  DCal+PHOS.	
  • Uncertainty	
  on	
  data	  points:	
  Pb+Pb	
  (central	
  0-­‐10%)	
  @	
  5.5	  TeV	
  one	
  year	  running	
  sta4s4cal	
  uncertainty	
  (=	
  0.5	
  nb-­‐1).	
  • Jet	  reconstruc4on:	
  FAST	
  jet	
  an4-­‐kT	
  algorithm,	
  R=0.4.	
Symposium on Jet Physics at RHIC and LHC, Hangzhou, China,
July 21, 2011 (T. Chujo)

19Case1:	
  Dijet	  in	
  p+p	Jet (trig)

Jet (assoc)(E TDCal # E TEMCal )" = DCal(E T + E TEMCal ) /2

• Dijet energy balance, Δ.
• No quenching (p+p)• True dijet peak Δ~0, except
without DCal.
• No clear peak EMC-TPC (noDCal).
• Asymmetric shape due to recoil
jet escape the acceptance of
DCal, and jet from BG.
•DCal is essential for better Δ
resolution.

Symposium on Jet Physics at RHIC and LHC, Hangzhou, China,
July 21, 2011 (T. Chujo)

20Case1:	
  Dijet	  in	
  p+p	Jet (trig)

Jet (assoc)l DCal improves the energy balance
resolution from ~35% to ~25% @ETEMCal = 60 GeV, down to <20% forhigher ETEMCal.

l Small effect by gap between PHOS
and DCal.

Symposium on Jet Physics at RHIC and LHC, Hangzhou, China,
July 21, 2011 (T. Chujo)21Case2:	
  Dijet	  in	
  Pb+Pb,	
  quenched	
  jet	Jet (assoc)

Jet (trig)•••(E TDCal # E TEMCal )" = DCal(E T + E TEMCal ) /2

•

Same	
  as	
  “Case1”	
  but,	
  required	
  trigger	
  
jet	
  in	
  DCal	  side	  instead.	
  “Tail”	
  on	
  posi4ve	
  side	  due	  to	
  trigger	
  for	
  DCal.	
  In	
  this	  case,	
  <qhat>	
  =	
  50	
  GeV2/fm,	
  and	  	  DCal	
  jet	
  energy	  threshold	
  of	
  100	
  GeV.	
  	
  Peak:	
  true	  dijet	
  with	  quencing.	
  
–

•

look	
  at	
  sigma,	
  and	
  centroid	
  to	
  quan4fy	
  the	  jet	
  quenching	  eﬀect	  (see	  next	  slide).	
  Tail:	  recoil	
  jet	
  out	  of	
  acceptance,	
  BG.	
  Symposium on Jet Physics at RHIC and LHC, Hangzhou, China,
July 21, 2011 (T. Chujo)22Case2:	
  Dijet	  in	
  Pb+Pb,	
  quenched	
  jet	
Width

CentroidJet (assoc)

Jet (trig)

150 GeV

150 GeV• Red:	
  <qhat>	
  =	
  50	
  GeV2/fm,	
  Black:	
  <qhat>	
  =	
  0	
  GeV2/fm.	
  • Broadening	
  of	
  peak	  is	
  seen	
  for	
  jet	
  quenching.	
  • Shi?	
  of	
  centroid	
  -­‐>	
  energy	
  loss.	
  • Using	  one	
  year	  Pb+Pb	
  running	
  (in	
  this	  model	  &	  parameter	
  set),	
  possible	
  to	
  study	  jet	  	  
	  quenching	  eﬀect	
  up	
  to	
  ETDCal	
  ~	
  150	
  GeV.	
Symposium on Jet Physics at RHIC and LHC, Hangzhou, China,
July 21, 2011 (T. Chujo)23Case	  3:	  π0-­‐jet,	
  control	
  path	  length	
Geometry of π0 trigger and associated recoil jet

Jet (assoc)

π0 (trig)• Trigger	
  π0	
  in	
  DCal,	  requiring	  jet	  in	
  EMCal.	
  • Producing	
  strong	
  geometry	
  bias	  by	
  hand,	
  i.e.	
  “control”	
  the	  path	
  length	
  of	
  jet.	
Symposium on Jet Physics at RHIC and LHC, Hangzhou, China,
July 21, 2011 (T. Chujo)24Case	  3:	  π0-­‐jet,	
  control	
  path	  length	Jet (assoc)

π0 (trig)• Hard scattering point (in x-y plane)of trigger π0 with associate recoil jet.
• The higher ET π0, the stronger
surface bias.
• <qhat> = 20 & 50 GeV2/fm• small difference.
à can be used as geometry
measure of emission point, without
knowing the quench parameters.
Symposium on Jet Physics at RHIC and LHC, Hangzhou, China,
July 21, 2011 (T. Chujo)25Case	  3:	  π0-­‐jet,	
  control	
  path	  length	Jet (assoc)

Recoil jet (EMC)

Trig π0 (DCal)

π0 (trig)

Path Length [fm]••••Path Length [fm]Trigger	
  π0	
  (right):	
  Minimizing	
  path	  length.	
  Recoil	  jet	  (lep):	
  Maximizing	
  path	  length.	
  Path	
  length	  	  of	
  jet	
  medium,	
  “control”	
  experiment.	
  Eﬃcient	
  trigger	
  of	
  π0	
  (Level	
  1)	
  is	
  the	
  key,	
  and	  it	
  is	
  capable	
  by	
  u4lizing	
  exis4ng	
  level	  26
1	
  readout	
  for	
  EMC.	
Symposium on Jet Physics at RHIC and LHC, Hangzhou, China,
July 21, 2011 (T. Chujo)Other	  interes/ng	
  measurements	
  with	  DCal	• γ-­‐jet:	
  – Golden	
  channel.	
  – Complementally	
  to	
  h	
  (π0)	
  -­‐jet,	
  jet-­‐jet.	
  • Medium	
  responses	
  with	  jet	
  axis	  	
  • Ridge	
  study	
  with	  di-­‐jet	
  &	
  π0	
  -­‐	
  jet	  	
  • Reac/on	
  plane	  dependence	
  of:	  – di-­‐jet	
  energy	
  balance	  – π0-­‐jet	
  • Discrimina/on	
  of	
  quark	
  jet,	
  gluon	  jet	
  High multiplicity p+p event @ 7 TeV (ALICE)– Study	  of	
  energy	
  loss	  mechanism.	
  – Mul4plicity,	  γ-­‐jet	
  (mostly	
  quark	
  jet)	
  can	  be	
  used.	
  • Heavy	
  ﬂavor	
  tagged	
  jets	  – Energy	
  loss	  for	  c,	  b	
  quarks.	
  • Mul/-­‐jet	
  events	  • Jet	
  quenching	  in	
  High	  mul/plicity	
  p+p	
  events?	
  Symposium on Jet Physics at RHIC and LHC, Hangzhou, China,
July 21, 2011 (T. Chujo)

27

4.	
  Current	
  status	
  and	
  schedule	• DCal	  has	  been	
  approved	
  by	
  the	
  ALICE	  collabora4on,	
  Oct.	
  2009.	
  • Module	
  produc4on	
  in	
  France,	
  Japan	
  and	
  China	
  has	  been	
  basically	
  completed.	
  – 3.0	  SM	  from	  Wayne	  State	  Univ.	
  (USA)	
  – 1.5	  SM	  from	  Tsukuba	
  (Japan)	
  – 1.0	  SM	  from	  	
  Wuhan	
  (China)	
  – 0.5	  SM	  from	  Nantes	  (France)	
  • Total:	
  6	
  SM	
  (192	
  x	
  6	
  =	
  1152	
  modules)	
  for	
  DCal.	
  • Integrated	
  SM	
  in	
  Nantes,	
  Grenoble.	
  	
  • Installed	
  in	
  the	
  ALICE	  experimental	
  area	  during	
  the	
  long	
  LHC	
  shutdown	
  in	
  2012-­‐2013.	
  Symposium on Jet Physics at RHIC and LHC, Hangzhou, China,
July 21, 2011 (T. Chujo)

28

EMCal	  status	
  in	
  2011	

• On	
  Jan.	
  2011,	
  EMCal	  installa4on	
  has	  been	  completed.	
  – 2880	
  modules	
  installed	
  in	
  10	
  super	  modules.	
  – Principal	
  construc4on	
  sites:	  	
  USA,	
  France,	
  Italy.	
  • Started	
  data	  taking	
  with	  the	
  full	
  EMCal	
  coverage	
  from	  LHC11.	
  Symposium on Jet Physics at RHIC and LHC, Hangzhou, China,
July 21, 2011 (T. Chujo)

29

Next,	
  DCal	

3/5 PHOS
10/18 TRD
18/18 TOF
7/7 HMPID
10/10 EMCALALICE Status
2x
2x

2x
5

2x

4

3

6

2

7

2x

1

8

0

9

17
10

16
15

11
12

13

14
4

0
1

2

3

Symposium on Jet Physics at RHIC and LHC, Hangzhou, China,
July 21, 2011 (T. Chujo)

11/07/21 2:03 PM

DCal	
  +	
  PHOS	

30

At	
  Tsukuba	
  (Japan)	
All module production has been completed (July 2011).

Symposium on Jet Physics at RHIC and LHC, Hangzhou, China,
July 21, 2011 (T. Chujo)

31

At	
  Nantes	  (France)	
All module production has been (or to be) sent to Nantes.

Symposium on Jet Physics at RHIC and LHC, Hangzhou, China,
July 21, 2011 (T. Chujo)

32

At	
  Catania	
  (Italy)	

Module Assembly & APD assembly/calibration at Catania
Symposium on Jet Physics at RHIC and LHC, Hangzhou, China,
July 21, 2011 (T. Chujo)

33

At	
  Wuhan,	
  CCNU	
  (China)	
All module production will be finished by July 2011.

Symposium on Jet Physics at RHIC and LHC, Hangzhou, China,
July 21, 2011 (T. Chujo)

34

5.	
  Summary	•Dijet Electromagnetic Calorimeter (DCal) in ALICE experiment
provide a powerful & crucial tool to investigate hot and dense matterin HI collisions at LHC, through dijet and π0-jet using jet axis:
1. Di-Jet correlations:• Energy balance of jet.
2. π0-Jet correlations:• Control path length of jet.

•

Together with other measurements (e.g. γ-jet, reaction plane dep.,
medium response), one may get a complete understanding of jet
quenching mechanism at LHC energy, i.e. “jet tomography”, and thenature of QGP.

•

DCal will be installed in the next LHC long shutdown (2012-2013), andwill be ready to take 5.5 TeV Pb+Pb data in the following year.
Symposium on Jet Physics at RHIC and LHC, Hangzhou, China,
July 21, 2011 (T. Chujo)

35

謝謝！	

Symposium on Jet Physics at RHIC and LHC, Hangzhou, China,
July 21, 2011 (T. Chujo)

36

BACKUP SLIDES	
Symposium on Jet Physics at RHIC and LHC, Hangzhou, China,
July 21, 2011 (T. Chujo)

37

DCal	  Integra/on	
  VHMPID

DCal

PHOS

11/07/21 2:03 PM
Symposium on Jet Physics at RHIC and LHC, Hangzhou, China,
July 21, 2011 (T. Chujo)

38

DCal	
  components	

Symposium on Jet Physics at RHIC and LHC, Hangzhou, China,
July 21, 2011 (T. Chujo)

39

Possibility of Parton ID
CDF, PRL94(2005)171802

lAs a new generation exp., from
Particle ID to Parton ID !

• According to CDF exp.,
charged/neutral workslMight be very difficult in heavy ion
gluon jetenvironment

quark jetlNevertheless, challenge!
lIt becomes feasible for higher pt
jetWorkshop for ALICE upgrades by Asian countries, Yonsei Univ. Seoul, Nov. 6, 2009 (T. Chujo)40Jet trigger in Pb+Pb
Fig.8.4 of TDR

Backgrounds
Rcone = 0.2
Ejet = 100 GeV
50 GeVlWith Rcone = 0.2, triggering jet of < 50 GeV

Rcone

becomes difficult.

lBack-to backWorkshop for ALICE upgrades by Asian countries, Yonsei Univ. Seoul, Nov. 6, 2009 (T. Chujo)

41

Full	
  jet	  reconstruc/on,	
  and	  	
  h-­‐jet	
  correla/ons	
  at	
  RHIC	Key to understand jet in HI collisions:(1) correlations, (2) fully reconstructed jet.

• Used fully reconstructed jet (by STAR TPC & EMC).
• Trigger high pT hadron, and look at recoil jet in away side, measureconditional yield in (Au+Au / p+p).
• Stronger suppression for lower recoil jet energy.
• indicating broadening of recoil jet cone size.
• “Controlled” surface bias.
Symposium on Jet Physics at RHIC and LHC, Hangzhou, China,
July 21, 2011 (T. Chujo)

42Case	  3:	  π0-­‐jet,	
  control	
  path	  length	Jet (assoc)

semi-inclusive jet spectrum(π0-jet)Au+Au/p+p

Symposium on Jet Physics at RHIC and LHC, Hangzhou, China,
July 21, 2011 (T. Chujo)

π0 (trig)

43

RHIC	
  vs.	
  LHC	
RHIC	

LHC	

√sNN	
  (GeV)	

200	

5500	

T/Tc	

1.9	

3.5-­‐4.0	

ε	
  (GeV/fm3)	

5	

15-­‐60	

τ	
  QGP	  (fm/c)	

2-­‐4	

>	
  10	

RHIC

• LHC:	
  Jet	
  produc/on	
  dominant.	
  – Study	
  the	
  maQer	
  by	
  clean	  many	  hard	
  probes,	
  and	
  look	  at	
  response	  of	
  bulk	  maQer	
  in	
  HI	
  collisions.	
  
LHC:	
  
Inclusive	  jets	  (R=0.4),	
  annual	  yield;	
  104	
  @	
  	
  
pT	
  =	
  200	
  GeV/c	
  (5.5	
  TeV,	
  Year-­‐1)
Symposium on Jet Physics at RHIC and LHC, Hangzhou, China,
July 21, 2011 (T. Chujo)

JPS 2010, Sep. 13, T. Chujo

RAA:	  	
  RHIC	  vs.	
  LHC,	
  Similar	
  RAA!	
  0-5% ALICE with 0-10%
PHENIX Centrality

0-5% ALICE with 0-5%
PHENIX Centrality

45
Symposium on Jet Physics at RHIC and LHC, Hangzhou, China,
July 21, 2011 (T. Chujo)

RAA:	
  Rise	  for	
  pT>10	
  GeV/c	  Minimum RAA is ~0.1 at pT~6 GeV/c; stronger suppression than RHIC (RAA~0.2)
Rise to RAA ~ 0.5 at pT~30-40 GeV/c and stay constant (?)
Symposium on Jet Physics at RHIC and LHC, Hangzhou, China,
July 21, 2011 (T. Chujo)

Where	  energy/momentum	
  goes	  (CMS)	
  (1)	
  Symposium on Jet Physics at RHIC and LHC, Hangzhou, China,
July 21, 2011 (T. Chujo)

Where	  energy/momentum	
  goes	  (2)	
  Symposium on Jet Physics at RHIC and LHC, Hangzhou, China,
July 21, 2011 (T. Chujo)