martinez

Report
The heavy ion collider
experiment @ LHC
ALICE
Ginés MARTINEZ#
for the ALICE Collaboration
#Photon
Group @ SUBATECH(IN2P3/CNRS – ENM - UN) Nantes, France
Ginés MARTINEZ, SUBATECH
Rencontres de Moriond March 17-24 2001
1
Outlook
1. Why a Heavy Ion
Experiment @ LHC?
2. Goals
3. Building ALICE
Ginés MARTINEZ, SUBATECH
Rencontres de Moriond March 17-24 2001
2
The study of the Quark Gluon
Plasma
Krasch QM2001
Lattice QCD calculations
nf=2 Tc = 173±8±SysErr MeV
nf=3 Tc = 153±8±SysErr MeV
ec= 700 ± 300 MeV
• QCD-thermodynamics
• Properties of the QGP and of
the phase transition:
– Chiral transition
– Deconfinement
Ginés MARTINEZ, SUBATECH
Rencontres de Moriond March 17-24 2001
3
Towards QCD
thermodynamics
The TOOLS:
Heavy Ion Collisions: SPS => RHIC => LHC
The relation with QCD at finite temperature
–
–
–
–
The pp & pA baseline
Equilibration
Probes of QGP formation?
QGP Initial conditions?
Ginés MARTINEZ, SUBATECH
Collision dynamics
Rencontres de Moriond March 17-24 2001
4
collision dynamics
Sensitivity to late stages
in HI collisions!
p+p and p+A
baseline !
Final state
probes
Penetrating
probes
The QGP phase
Ginés MARTINEZ, SUBATECH
Rencontres de Moriond March 17-24 2001
5
Why HI program @
Central collisions SPS
RHIC
LHC ?
LHC
s1/2(GeV)
17
200
5500
dNch/dy
500
700-1500
3-8 x103
e (GeV/fm3)
2.5
3.5-7.5
15-40
Vf(fm3)
103
7x103
2x104
tQGP (fm/c)
<1
1.5-4.0
4-10
t0 (fm/c)
~1
~0.5
<0.2
@ LHC : Hotter – bigger - longer
Ginés MARTINEZ, SUBATECH
Rencontres de Moriond March 17-24 2001
J. Schukraft QM2001
6
The gluon-gluon
physics…
•
Gluon distribution in nuclei grows for small values of x
= 2pT /s1/2 and high gluon densities are reached .
• For high densities (rT >> L2QCD ) in large nuclei &
small x, the gluon distribution can be computed in the
weak coupling method.
• The classical color field.
• A large number of gluons are freed in the early stage of
the collision => Equilibration
PRD10(74)1649, PRC49(94)2233, PRD49(94)3352, PRD53(96)458, PRC56(97)2219
Ginés MARTINEZ, SUBATECH
Rencontres de Moriond March 17-24 2001
7
Advantages of Pb+Pb
collisions @ LHC
• Better connection with QCD theory (via the
asymptotically free field theory) A E
–
–
–
–
–
–
Initial gluon multiplicity (R.Venugopalan QM01, PRL86(01)1717)
Initial equilibration conditions (D. Son QM01,hep-ph/0009237)
Longer lifetime of the plasma
Ideal plasma : e/ec ~ 5 : higher T
Zero baryon density (already p/p ~ 0.6 @ RHIC)
New probes : Jets, Open charm & beauty, bottonium
Ginés MARTINEZ, SUBATECH
Rencontres de Moriond March 17-24 2001
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Final state probes
•
•
•
•
•
Forward energy
dN/dy
hadron pT distribution
Particle ratios
Strange particles
-1<h<1
Pb+Pb @ 5.5A TeV
Ginés MARTINEZ, SUBATECH
•
•
•
•
•
•
Multiplicity
Energy Density
HBT and dynamical evolution
Freeze-out temperature
Fluctuations
Collective motion
• 12200 p’s
• 1700 K’s
• 700 h’s
• 570 p, n, p, n ‘s
• ….
Rencontres de Moriond March 17-24 2001
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Penetrating probes
• Real and virtual
photons
• Quarkonia: J/Y & Y
• Open Charm &
Beauty
• Light vector mesons
• Jets
Ginés MARTINEZ, SUBATECH
• Initial stage
• Thermal radiation: Tini
• Colour screening of
heavy quarks
• Jet-matter interaction
• Chiral transition
Rencontres de Moriond March 17-24 2001
10
Jet Matter interaction
Large production of jets @ LHC energies
1 jet/GeV/s in the ALICE acceptance
at ET =50 GeV
1-3 GeV/fm#
Dt0
B
A
Looking for Jet matter interaction:
1. High pT particle distributions
2. Identification of jets …
3. Tagging with photons:
• High pT particles
• Jets
g
#Interference
with vacuum and LPM,
Jet enhancement
Ejet dependence of DE
pT> 10 – 20 GeV
Ginés MARTINEZ, SUBATECH
Urs. Wiedemann QM2001 et NPB588(00)203
Rencontres de Moriond March 17-24 2001
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Building
•
•
•
•
•
•
Event Characterisation
dNch/dy
pT distribution
Particle ratios
Strange baryons
Fluctuations
Ginés MARTINEZ, SUBATECH
•
•
•
•
•
•
ALICE
Light vector mesons
Quarkonium
Open charm & beauty
Photon & Dilepton
Jet quenching
…
Rencontres de Moriond March 17-24 2001
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dNch/dh
• Time Projection Chamber: Main
tracking detector of ALICE central
barrel
• Inner radius: Track separation
Rin = 0.8 m
• Outer radius: dE/dx & p resolution#
Rout= 2.5 m
• Large acceptance Dh <0.9
• 200Hz rate capability
• MWPC read-out 32 m2, 40% Oc
• 5 105 pads x 500 time bins
• 60 Mbyte/evt => DC, RoI, L3 …
#Magnetic
field of the L3 magnet 0.4T
5% @ 5 GeV/c
Ginés MARTINEZ, SUBATECH
Dh=1~
8000
Tracking efficiency ~90%
2 tracks eff. 80% Dp>15 MeV/c
5m
TPC
Ne+CO2(10%)
1. PID below ~600 MeV/c
2. Low Dp tracks
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The
• 0.5 < p < 5 GeV/c
• e, p, K, p
pT distributions
•Particles ratios: Tfreeze-out
•Fluctuations
•Strangeness production
•Light vector mesons
•Open charm
•Jet physics
Ginés MARTINEZ, SUBATECH
ALICE PID
Time of Flight
High Momentum Particle Identification
Transition Radiation Detector
ToF prototype
ToF
Multigap
Resistive
Plate
Chamber
• Large acceptance
• MRPC
• s= 150 ps
• p,K,p
• 0.5<p<2.5 GeV/c
Rencontres de Moriond March 17-24 2001
10cm
14
High momentum particles
High Momentum PID:
• Hard processes
1 GeV/c < p < 5 GeV/c
Rich-imaging technique
Small acceptance
7x
HMPID
Ginés MARTINEZ, SUBATECH
Rencontres de Moriond March 17-24 2001
15
Electron Identificator of
ALICE
• J/Y in Zero baryon density
• Open charm normalization
• J/Y source from Open Beauty
• D annihilation?
• G production
• Light vector resonances: f, w
e
channel
TRD
• Electron detector
• 10-3 pion rejection
• Large acceptance
• Transition Radiation Detector
Pb+Pb central collisions
6x
g ~ 103
EX ~ 3-30 KeV
Ginés MARTINEZ, SUBATECH
Rencontres de Moriond March 17-24 2001
16
Primary and secondary
Vertex Position
• Secondary vertex from hyperon
decays
• Open charm & beauty physics
• Tracking of low pT particles
• Improving momentum
resolution
• Strangelets
W-
p
L
K-
p-
I
T
S
ITS
• Large acceptance
• 15000 tracks
• s~100mm in rf
6 Silicon layers:
1. 2 Silicon Pixel layers
2. 2 Silicon Drift layers
3. 2 Silicon Strip layers
Ginés MARTINEZ, SUBATECH
D =>Kp
107 evt
Rencontres de Moriond March 17-24 2001
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Photon detection
10
• Thermal radiation
5x
• High pt physics
• Tagged jets
• 1200 g pT>40 GeV/c
1
0.1
PHOS
5%
PHOS Module
hep-ph/9906325
1
2
3
4 pT(GeV/c)
• EM calorimeter
• PbWO4: spectrometer: p0,h
• Small acceptance 0.07 DhDf/2p
• 1< pT < 5 GeV/c
• 5< pT <100 GeV/c
Ginés MARTINEZ, SUBATECH
Rencontres de Moriond March 17-24 2001
18
Di muon channel
Quarkonium physics:
J/Y and Y families
s~ 100 MeV
2.4 < h < 4.0
DiMuon
em coin.:
•Intermediate
rapidity
•DD, BB
production
Ginés MARTINEZ, SUBATECH
Rencontres de Moriond March 17-24 2001
19
ALICE = The result of QGP physics
requirements at LHC
+
PMD
FMD
CASTOR
ZDC
Trigger
DAQ
Offline
Ginés MARTINEZ, SUBATECH
Rencontres de Moriond March 17-24 2001
20
Running conditions
•
•
•
•
•
•
•
Pb+Pb @ 5.5A TeV
106s per year
8000 Hz (L=1027 cm-2s-1)
Data rate full ALICE 50 Hz (TPC challenge)
pp & pA running
Lighter ions @ higher luminosity.
Beginning 2007
Ginés MARTINEZ, SUBATECH
Rencontres de Moriond March 17-24 2001
21
conclusions
•
HI in LHC: a rigorous step towards the QGP
physics
–
–
•
The LHC HI dedicated experiment: ALICE
–
•
•
Perturbative + weak coupling methods
Direct partonic probes: Jets.
Penetrating and final state probes
884 members & 28 countries & 77 institutes
Rendez-vous @ CERN March-April 2007
Ginés MARTINEZ, SUBATECH
Rencontres de Moriond March 17-24 2001
22
A new research domain
Quark Matter
2002
in
Nantes
Ginés MARTINEZ, SUBATECH
Rencontres de Moriond March 17-24 2001
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