OGCF@K8K@FEF=?8I;
(GIF9<J8E;%<KJ
KFJKL;PK?<,"+
N@K?'#'$
ALICE DCal Proposal Revision 0.0

March 2010

48JLF($&
0E@M F=/JLBL98

YasuoviewMIAKE,
Juneand
15,PHOS2010,
LAPP, onFranceIV.2 Perspectiveof the DCal
integrated
a common support. As
discussed in the text, the support structure is a component of the full international project1

*LKC@E<✓,"+• N?8KN<C<8IE<;8K-#$
8E;?FD<NFIB=FI'#

✓%<KHL<E:?

• %<KJ ?8I; (• GIFG<IKPF=,"+✓@%<K8CFI@D<K<I• ;<J@>EI8K<JJ:?<;LC<• %8G8E!I<E:?:FCC89FI8K@FE)<NGIFGFJ8C@E
!%++'@EK?@JK8CB
=F:LJFE%<K,L<E:?

✓E8CPJ@J(<:?8E@JD✓.LDD8IP
Yasuo MIAKE, June 15, 2010, LAPP, France

2

,L8IB"CLFE+C8JD8RHIC(200GeV)
since 2000

LHC(5.6TeV)
soon✓+?PJ@:JF=,@E<OKI<D</i8E;JD8CCO✓)L:C<LJ)L:C<LJ:FCC@J@FEJ
Yasuo MIAKE, June 15, 2010, LAPP, France3

2?8KN<C<8IE<;8K-#$
3

�QGP ∼ 2 [GeV/fm ]
�QGP
2GeV
< nq,q̄ > ∼∼∼5< mT >
0.4GeV
1
λq =
nσqq
1
∼
= 0.5 [fm]5 × 0.4
λq � Rsystem

N<CC<JK89C@J?<;!#8;IF:?<D@:8C<HL@C@9I@LD/gY!&@E<D8K@:8C<HL@C@9I@LD/b
!0E@M<IJ8CGK8Q@DLK?8C;@JKI@9LK@FEJF=HL8IBJ
,L8IB:F8C<J:<E:<DF;<C
Yasuo MIAKE, June 15, 2010, LAPP, France

w So
el f
lu tp
( I nd hy
th e siin rs csk) tood

• .KIFE>CP@EK<I8:K@E>,"+• .K8K@JK@:8CE8KLI<JG8:< K@D<<MFCLK@FEF=:FCC@J@FEJ

4

"FF;K<OK9FFBFE,"+

Yasuo MIAKE, June 15, 2010, LAPP, France

5

-#$MJ'#
IV.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.

-#$_J))"<1

'#

28



/ /:







d"<1 =Dj,"+=D :✓#FD<NFIBKFK?<'#G?PJ@:JF=A<KHL<E:?
!'#?8JJLG<I@FI8;M8EK8><@E?8I;GIF9<J
Yasuo MIAKE, June 15, 2010, LAPP, France

6Jet quenching3

W%<K,L<E:?X

nt non-perturbatively into a set of final-state hadrons. The characteristic collited spray of hadrons resulting from the fragmentation of an outgoing parton isled a “jet”.

✓/NFHL8IBJJL==<I8

IV.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.

?8I;J:8KK<I@E>@E:FCC@J@FE
28• *E<>F<JFLKKFM8:LLD

:I<8K@E>A<K• 9LKK?<FK?<I>F<JK?IFL>?K?<,"+
JL==<I@E><E<I>PCFJJ;L<KF>CLFE✓(8E@=<JK8K@FE

8KK<EL8K@FE•. 2. “Jet quenching” in a head-on nucleus-nucleus collision. Two quarks suffer a hard scat-

W%<KHL<E:?@E>X@EEL:C<LJ
EL:C<LJ:FCC@J@FE•

ng: one goes out directly to the vacuum, radiates a few gluons and hadronises,;@J8GG<8I8E:<F=A<K
the others through the dense plasma created (characterised by transport coefficient q̂, gluon
densityJLGGI<JJ@FEF=?@>?GKg /dy and temperature T ), suffers energy loss due to medium-induced gluonstrahlung and?8;IFEJ
lly fragments outside into a (quenched) jet.
Yasuo MIAKE, June 15, 2010, LAPP, France• DF;@=@:8K@FEF=A<K=I8>

7

E<8IJ@;<(F;@=@:8K@FEF=
98:BKF98:B:FII
8N8PJ@;<.K8I+ - '    G/KI@>R"<1 :[G/8JJF: "<1 :

pedestal and flow
subtracted

Yasuo MIAKE, June 15, 2010, LAPP, France✓@I<:K<M@;<E:<F=

CFJJF=UA<KV✓Q@DLK?8C
:FII<C8K@FEN I K ?@>?
GKC<8;@E>G8IK@:C<KI@>><I!

GG:C<8E;@A<K!

;LJ@D@C8IKFGG!

LL.@D@C8IFEK?<
J8D<J@;<JL>><JK@E>
A<KC@B<D<:?8E@JD9LK9
KF9;@J8GG<8I<;
"==<:K@JEFK@E@E@K@8C
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@E;<EJ<D8KK<I
:I<8K<;@ELL
8

.LGGI<JJ@FEF=?@>?GK
G8IK@:C<J
NuclearModification
FactorRAA =”hot/dense QCDmedium”
dnAA /dpT dy=”QCD vacuum”
�Nbinary � · dnpp /dpT dy

Scaled pp
spectra<EKI8C+<I@G?<I8C~ 0.2✓+@FEJ8I<JLGGI<JJ<;;@I<:KG?FKFEJ8I<EFK
Yasuo MIAKE, June 15, 2010, LAPP, France9E<8IJ@;<

?8E><F=J?8G<@EK?<8N8PJ@;<
8N8PJ@;<

G/KI@>R"<1 :[G/8JJF:+# )$38I3@M    S6EL:C<O7

@
PJ

JF
J
F

;<

N8
8

=

'

✓!IFD9IF8; EFE<KF;@JK@E:KKNFJ?FLC;<IJ8K
`a\hZ N@K?;<:I<8J@E>DFD<EKLD• @J:LJJ<;@EK<IDJF=(8:?FE<?<I<EBFM D

Yasuo MIAKE, June 15, 2010, LAPP, France10

2?PK?<A<K
HL<E:?@J@DGFIK8EK?8I8:K<I@JK@: E<I>P'FJJ@E;<EJ<D8KK<I^
K?<GIFG<IKP
F=K?<D8KK<I
Yasuo MIAKE, June 15, 2010, LAPP, France

11Energy losses in QED

E<I>PCFJJ@E, 

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

IV.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.

Stopping power [MeV cm2/g]

Energy loss of charged particle in a matter

Bremsstrahlungµ+ on Cuµ(

10LindhardScharff

100

Bethe-BlochFCC@J@FE8C✓<K?<CF:?
28

Radiative-8;@8K@M<✓<K?<#<@KC<I

AndersonZiegler

Eµc
Minimum
ionization

NuclearlossesRadiative
effects
reach 1%

Radiative
lossesTK?@E'f✓'8E;8L

Without %+FD<I8E:?LB
(@>;8C
K?@:B'f

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]✓Fig. 4. Stopping
power, −dE/dl, for positive muons in copper
as a function of &' = p/Mc
(or(<8JLI<D<EKJF=;;O>@M<JGIFG
F=D8KK<I
momentum p). The solid curve indicates the total stopping power [15].

• E<I>PCFJJ@E, GC8JD8>@M<J/D@E=F

Yasuo MIAKE, June 15, 2010, LAPP, France

Yet, the hot and dense plasma environment that one encounters in “jet quench-122 /(2m2 ) ≈ 1.5
themomentum
diffusion( –freethe average momentum squared gained
on is &gg # to9#!
mb. Thecoefficient
gluon mean
s
D
by
the
particleperunit-time(relatedtotheis 'g = 1/("g &gg ) # 0.45 fm (the quark mean-free-path istransport coefficient as ( ≈ q̂ v) – andmomentumdragofcoefficient)D . colour
where CA /Cthe
9/4 is the ratio
gluon-to-quarkF =2
coefficient is therefore q̂ # mD /'g # 2.2 GeV2 /fm. Notevalue hasobtained witha LO expression
in loss!s for
2.2beenMechanisms
of in-medium
energyss section. Higher-order scatterings (often encoded in a
uld well In
resultin muchlargerof q̂. loss of a particle traversing a medium is the sum of
a generalway,
the values
total energy
4 : *ED, characterising
dynamics
heavy
non-relativisticcollisionaltheandradiativeofterms= *Ecoll + *Erad . Depending on the kinematic
5 inEinspeed v)region,
traversing
the plasma,is connected,
via thea (colour)chargecan lose energy
a plasma with temperature T mainly by
6
two mechanisms .
D = 2T 2 /( = T /(M )D )(3)

E<I>P'FJJ@E,

ion coefficient ( – theEaverage momentum
squared gained
E-!Etime (related to the transport coefficient as ( ≈ q̂ v) – andE
efficient )D .
!E

dium energy loss

FCC@J@FE8C

IV.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.

!E
E-!E
28

nergy loss of a particle traversing a medium is the sum ofX
rms4 : *E = *Ecoll + *Erad . Depending on the kinematic (medium)an lose energy5 in a plasma with temperature T mainly by
Fig. 3. Diagrams for collisional (left) and radiative (right) energy losses of a quark of energy
E traversing a quark-gluon medium.

E

E

•

E

!E

Collisional energy loss through elastic scatterings with the medium constituents(Fig. 3, left) dominates at low particle momentum. The average energy loss in-8;@8K@M<

E-!E by powers of ! c # 0.2 GeV fm (other useful equalities:
3 For unit conversion, multiply
10 mb = 1 fm2 , and 1 GeV−2 = 0.389 mb).

X
4 In addition, synchrotron-,Čerenkov- and transition-radiation energy losses can take placerespectively(medium)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.
al (left) and 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,edium.
12, 13, 14] for QCD plasmas – are generally less important in terms of the amount of Eloss .
5 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.
s through 6elastic
scatterings
with themediumconstituents
Note thatthe separation
is notso clear-cut
since the diagrams assume well-defined asymps at low particle
momentum.
Theoutgoingaverageparticles
energymay
lossstillin be in the medium and further rescatter.
totic outstates, but the✓(8EPK?<FI@<JFE• FCC@J@FE8CCFJJ• -8;@8K@M<CFJJ

iply by powers of ! c # 0.2 GeV fm (other useful equalities:−2 = 0.389 mb).
Čerenkov- and transition-radiation energy losses can take placenteracts with the medium magnetic field, if its velocity is greater
y of light, or if it crosses suddenly from one medium to another.
may lead to energy losses. Yet, those effects – studied e.g. in [11,as – are generally less important in terms of the amount of Eloss .
he particle is similar to the plasma temperature, E ∼ O(T ), thegy while traversing it.
not so clear-cut since the diagrams assume well-defined asympgoing particles may Yasuo
still be inMIAKE,
the medium
and15,
further
rescatter.
June
2010,
LAPP, France!<K?<#<@KC<II<>@D<!'+(I<>@D<!W;<8;:FE<X<==<:K∆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 13

#FNN<JKL;P%<KHL<E:?
8K'#(<8J F=?@>?GKJLGGI<JJ@FE#8;IFE:FII^!LCC98:BKF98:BA<K
8E8CPJ@JF=?@>?<I<E<I>PA<KJ

Yasuo MIAKE, June 15, 2010, LAPP, France

14

8C8J8E<OK<EJ@FEF=
(8C

✓!FI9<KK<IG<I=FID8E:<

IV.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.

F=98:BKF98:B:8G89@C@KP!<=@E<98:BKF98:BA<KJ!/I@>><I98:BKF98:BA<KJ

'$  ('28✓+IF>I<JJ• +IFGFJ<;@E!<9  • @J:LJJ<;N $) +@E(8P

OK<EJ@FEGIFGFJ<;

@%<K8CFI@D<K<I
Yasuo MIAKE, June 15, 2010, LAPP, France• @J:LJJ<;@E(8I:? • +IFGFJ8C@E(8P • +8IK@8C8GGIFM8C@E%LCP • !LCC8GGIFM8C9P'$ @E*:K  ✓FEJKIL:K@FEJK8IK<;
15

EMC-2

<8D1@<N

EMC-1

EMC-3

✓:FEK@>LFLJ
6

DF;LC<JGFJJ@9C<
N?@C<<O8:K98:B
KF98:B@J

g
e
d
0

EMC-5

e
60 d

g
JCal-3JCal-1

Yasuo MIAKE, June 15, 2010, LAPP, France

JCal-216

+IF9<J=FIK?<JKL;P
IV.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.

c%<K

@A<Kh %<K28✓,L8IB%<K✓(FJKCP"CLFE%<K✓.D8CC3J<:K@FE ✓'8I><I3J<:K@FE✓ OG<I@D<EK8CCP ✓$EK<IGI<K8K@FE
:?8CC<E>@E>@J:FDGC@:8K<;✓C<8Eh KI@>✓'8I><3J<:K@FE✓$DGFIK8EK=FI
8C.PJK<D8K@:D<8J F=K?<J<GIF:<JJ<J=FIDF;<C:FDG8I@JFEGIFM@;<J8K?@>?GI<:@J@FEC<M<C
Yasuo MIAKE, June 15, 2010, LAPP, France

17

2?8KN<<OG<:K
-<8:?F=%<K E<I>P
IV.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.

✓!FI<M<EKJ

~1

~2

00

00

G

G

eV

eV

28

P<8I@E+9+9 /<1• $E:CLJ@M<A<KLGKF
"<1• @%<KKF

Yasuo MIAKE, June 15, 2010, LAPP, France

"<1
18

a “jet”.

E1JET

2?8KN<<OG<:K
J<EJ@K@M@KP!

IV.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.

E1JET − E2JETBalance ≡1/2(E1JET + E2JET )

28

E2JET

“Jet quenching” in a head-on nucleus-nucleus collision. Two quarks suffer a hard scatone goes out directly to the vacuum, radiates a few gluons and hadronises, the otherough the dense plasma created (characterised by transport coefficient q̂, gluon density
and temperature T ), suffers energy loss due to medium-induced gluonstrahlung andragments outside into a (quenched) jet.

Figure II.7 Distribution of di-jet energy balance ! for quenched jets
2(qhat = 50 GeV /fm), for DCal jet energy threshold of 100 GeV. Error
bars show the statistical precision of the signal for 0.5 nb-1 of 5.5 TeV

e of the first proposed “smoking guns” of QGP formation was “jet quench] i.e. the attenuation or disappearance of the spray of hadrons resulting fromgmentation of a parton having suffered energy loss in the dense plasma proin the reaction (Fig. 2). The energy lost by a particle in a medium, !E, proundamental information on its properties. In a general way, !E depends bothcharacteristics of the particle traversing it (energy E, mass m, and charge) andplasma properties (temperature T , particle-medium interaction coupling1 ",ckness L), i.e. !E(E, m, T, ", L). The following (closely related) variables are
ely useful to characterise the interactions of a particle inside a medium:mean free path # = 1/($%), where $ is the medium density ($ & T 3 for an
al gas) and % the integrated cross section of the particle-medium interaction2,
opacity N = L/# or number of scatterings experienced by the particle in adium of thickness L,
Debye mass mD (T ) ∼ g T (where g is the coupling parameter) is the inverse of
screening length of the (chromo)electric fields in the plasma. mD characterises
Yasuo MIAKE, June 15, 2010, LAPP, France
typical momentum exchanges with the medium and also gives the order of

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

✓ .<EJ@K@M@KP@E;8K8F=
P<8I

!
19

JJ<D9C<;@E%8G8E$K8CP

8C8JJ<D9CP
+K<JK<;@E$K8CP

ALICE DCal Proposal Revision 0.0

JJ<D9C<;@E"I<EF9C<)8EK<J

March 2010

$EJK8CC<;8K -)/<JK<;@E)8EK<J

IV.2 Perspective view of the DCal and PHOS integrated on a common support. As
Yasuo MIAKE, June 15, 2010, LAPP, France
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.

20

France-Japan collaboration for ALICE-DCal
Institute & People
LPSC Grenoble• Christophe Furget• Jean-François Muraz

DCal SM platform (LPSC)

DCal support structure (Subatech)

Subatech Nantes• Manoel Dialinas
IPHC Strasbourg• Christelle RoyContributions to DCal

DCal SM shipping crate (LPSC)

LPCS Grenoble:-DCal module straps-DCal supper module (SM) cables-DCal platform, shipping boxes-DCal SM assembly

DCal installation tool (Subatech)

DCal straps (LPSC)
Subatech Nantes:•DCal SM installation tool, support structure, integration•DCal strip module production, DCal strong back
DCal weight cal. (Subatech)
2

LPSC Grenoble (July, 2009)

Christophe Furget

Jean-François Muraz
3

4

ALICE DCal Proposal Revision 0.0

March 2010-<JGFEJ@9@C@K@<J
Table V.1 Proposed individual group responsibilities for the major national groups
participating in DCAL.
Group
USA

Group Leader
T.J. Symons, LBNL

Japan
FranceY. Miake, Tsukuba
C. Roy, IPHC Strasbourg

China
Italy

D. Zhou
N. Bianchi

Proposed Responsibilities
3 super modules
Detector design
Overall project management
Project technical coordination
DCal LED system
1.5 super module
0.5 super modules
Support structure design, fabrication
Oversight and payment of up to 2/3 thecost
Installation tooling design
Installation oversightJet trigger Design, hardware and integration
SM integration and cosmic calibration
1 super module
Module assembly
Fiber production facilities

As this document is written and before the multi-national LOI is emplaced, the distributionof proposed project responsibilities, as it is presently understood, is given in Table V.1.

Yasuo MIAKE, June 15, 2010, LAPP, France24

!"#"$%&%'($")*&+&',"-+)+.*'/+&-0&&%/'1+.2',3%$-2'%4#%3.&'
1+.2+$'(&+"$'-5660$+7%&'".'8+35&2+6"'+$'!"$9':;<;
Remarks from the workshop;! Active discussion started.
! FJPPL project members involved.
! Successful PROOF demo. carried out.
! Asian communities quite interested in.
! Task-force group formed.
! All activities are in scope of this project.

FJPPL project members in color

JP
KR FR
JP KR KR JP JP
JP
JP
JP FR JP CN CN CN CN JP

ALICE Tier-2 at Hiroshima"The ALICE WLCG site “JP-HIROSHIMAWLCG” with EGEE/gLite3.2 on SLC5;"A full WLCG service up and running;
VOBOX , LCG-CE, CREAM-CE, BDII,WMS/LB, XROOTD-SE, APEL, UI, etc..
"CPU and storage resources;
752 Xeon-cores and 276 TB disk
servers
Currently ~2/3 of resources in local
use"Network B/W: MPLS 1Gbps to KEK on
SINET3"ALICE associated Tier-1 in CCIN2P3/
Lyon
37/50Mbps to CCIN2P3/Subatech"Responsible by Prof. T. Sugitate/Deputy
Leader! Some more resources at Tsukuba andTokyo.

Summary of Japanese Analysis Facility"Infrastructure (CPU, storage, network) exists in Asian
institutes, e.g., at Hiroshima and KISTI"Software framework exists or under development in
French institutes"Closer collaboration between France/Japan turns outto! challenge fast data analyses and strengthen Asian
communities! establish and spread new technologies, e.g.,
PROOF on GRID
! innovate a global computing model at large
distances"Primary people involved and request! France: YS/SUBATECH, RV/CCIN2P3, ??
! Japan: TS/Hiroshima, HH/Tokyo, ??/Tsukuba

*LII<HL@I<D<EKJ✓!I<E:?

G<FGC<8JB@E>

✓%8G8E<J<G<FGC<8JB@E>
Yasuo MIAKE, June 15, 2010, LAPP, France€=FIKI8M<C
B]=FIJLGGFIK
28

.LDD8IP✓)<N8GGC@:8K@FEKF!%++'✓JB@E>JLGGFIK=FI8C (8CGIFA<:KJ
• N?@:??8J<D<I><8JI8G@;>IFN@E>GIA<:KJ8K
'$

• /@>?K<E%8G8E!I8E:<0.$K8CP?@E8
:FCC89FI8K@FE• 8@CP:FCC89FI8K@FE9<KN<<E%8G8E!I8E:<!/NFJKL;<EKJ +N@CCJK8P)8K<J"I<EF9C<

Yasuo MIAKE, June 15, 2010, LAPP, France

29