The ALICE Experiment at the CERN LHC

P. Kuijer

for the Alice collaboration

ICHEP 2002

ICHEP, 27-7-2002 P. Kuijer 2

SPS-RHIC-LHC

Hotter, bigger and longer life time at higher energies:

Alice: properties of QGP well above threshold

PbPb central SPS RHIC LHC

dNch/dy 500 700-1500 2000-8000e [GeV/fm3] 2.5 3.5-7.5 15-40

Vf [fm3] 103 7*103 2*104

tQGP [fm/c] <1 1.5-4 1-10

t0 [fm/c] 1? 0.5 <0.2?

tQGP/t0 1 6 30

ICHEP, 27-7-2002 P. Kuijer 3

Observables for Alice• AA Event by event!

– Particle multiplicities: scaling laws pp to AA

– Particle correlations: Flow (eq of state) and HBT (size, lifetime)

– Particle spectra: Kinetic freeze-out temperature + suppression

– Particle yields: Chemical freeze-out temperature + suppression

– Jets: Energy loss of partons in matter

– Direct photons: Yield increases strongly with T

– Heavy quark + quarkonia: pQCD production + modification in medium

• pp and pA– Global pp properties: baseline for AA

– Structure functions in nuclei (shadowing)

• Cosmics– muons around ‘knee’ region

ICHEP, 27-7-2002 P. Kuijer 4

Alice detectors

•Low pT cut-off

•Particle ID

•High granularity tracking

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TRD e / PHOS /

TPC + ITS (dE/dx)

/K

/K

/K

K/p

K/p

K/p

e /

e /

HMPID (RICH)

TOF

ALICE uses ~all known methods

P [GeV/c] 0 1 2 3 4 5

P [GeV/c] 1 10 100

•p, K, identified in 2*1.8 units of by tracker (dE/dx) and TOF for 100 MeV/c up to several GeV/c

•e identified from 100 MeV/c to 100 GeV/c by tracker+TOF+TRD

•HMPID extends identification in small acceptance up to 5 GeV/c

•Photons with high resolution in PHOS, counting in PMD

ICHEP, 27-7-2002 P. Kuijer 6

HMPID

TOF

ITS+TPC

TPC

PID performance

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SSD

0

50

100

150

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350

1999 2000 2001

DAQ

Mass Storage (sust)

Mass Storage (peak)PHOS

• R&D phase finishing

PIX

SDD

0 100 200 300 400 500 600 700-50

0

50

100

150

200filter inputthreshold

0 100 200 300 400 500 600 700-50

0

50

100

150

200Filtered data and fixed threshold

filter outputthreshold

TPC

TOF

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•Production phase starting

SSD support

HMPID module

Muon stations 3-4 and 1-2

TPC field cage

TPC RO chamber

Muon magnet yoke

PHOS crystals

ICHEP, 27-7-2002 P. Kuijer 9

• Point 2 ready to receive ALICE

TPC assembly hall taking shape

ICHEP, 27-7-2002 P. Kuijer 10

Alice collaboration

0

200

400

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1990 1992 1994 1996 1998 2000 2002 2004

ALICE Collaboration statistics

LoI

MoU

TP

TRD

UKPORTUGAL

JINR

GERMANY

SWEDEN

CZECH REP.HUNGARYNORWAY

SLOVAKIAPOLANDNETHERLANDS

GREECE

DENMARKFINLAND

SWITZERLAND

RUSSIA CERN

FRANCE

MEXICOCROATIA ROMANIA

CHINA

USAARMENIA

UKRAINE

INDIA

ITALYS. KOREA

77 Institutions, 28 Countries

937 members (63% from CERN MS)

ICHEP, 27-7-2002 P. Kuijer 11

Summary

• Alice is an all-round Heavy Ion experiment– Excellent pT acceptance: 100 MeV/c up to 100 GeV/c

– Good particle ID

– The project is in transition from R&D to production

• The collaboration is still growing

• ALICE is on track for 2007!