physics performance of alice
DESCRIPTION
Physics Performance of ALICE. Overview The LHC as Ion collider SPS-RHIC-LHC Global properties in the LHC regime ALICE and its experimental strategy Suite of detectors Performance Status. David Emschermann / IRTG meeting. Heavy Ion Collisions. 5.5. 10 27. 70-50. 10 6 **. 7.7. - PowerPoint PPT PresentationTRANSCRIPT
June 2005 1
Physics Performance of ALICE
• Overview• The LHC as Ion collider• SPS-RHIC-LHC• Global properties in the LHC
regime• ALICE and its experimental strategy
• Suite of detectors• Performance• Status
David Emschermann / IRTG meeting
June 2005 2
Heavy Ion Collisions
June 2005 3
LHC as Ion Collider
• Running conditions:
• + other collision systems: pA, lighter ions (Sn, Kr, Ar, O) & energies (pp @ 5.5 TeV).
Collision system
PbPb
pp
<L>/L0
(%)
107
Run time
(s/year)
geom
(b)
L0
(cm-2s-1)
√sNN
(TeV)
0.071034 * 14.0
70-50 106 ** 7.710275.5
*Lmax(ALICE) = 1031 ** Lint(ALICE) ~ 0.7 nb-1/year
June 2005 4
From SPS to RHIC to LHC‘hotter – bigger – longer lived’
<0.2~0.5~10 (fm/c)
4–101.5–4.0<1QGP (fm/c)
2x1047x103103Vf(fm3)
15–404–52.5 (GeV/fm3)
2–8 x103850500dNch/dy
550020017s1/2(GeV)
LHCRHICSPSCentral collisions
Formation time τ0 3 times shorter than RHICLifetime of QGP τQGP factor 3 longer than RHICInitial energy density ε0 3 to 10 higher than RHIC
June 2005 5
Novel aspects… Multiplicity
hep-ph0104010
5
√s (GeV)10 102 103 102 103 104
1.0
5.0
10.0
15.0
Nch
/(0
.5N
par
t)
dN
ch/d
|<
1
2
5
103
dNch/d ~ 1500dNch/d ~ 2500
(from K.Kajantie, K.Eskola)
Even with RHIC data extrapolation to LHC uncertainExpect multiplicity in range dN/dy (charged) ~ 1500 to 6000ALICE optimized for dN/dy(charged) 4000; operational up to ~ 8000
June 2005 6
Novel Aspects… soft processes
10-6 10-4 10-2 100
x
108
106
104
102
100
M2 (
GeV
2)
• Probe initial partonic state in a novel Bjorken-x range (10-3 - 10-5):• nuclear shadowing,• high-density saturated
gluon distribution.• Larger saturation scale
(QS=0.2A1/6 √sδ= 2.7 GeV): particle production dominated by the saturation region.
June 2005 7
Novel Aspects…Hard processes
LHC
RHIC
SPS
(h++h-)/2
0
17 GeV
200 GeV
5500 GeV=√s
LO p+p y=0
Hard processes contribute significantly to the total AA cross-section (σhard/σtot = 98%) Bulk properties
dominated by hard processes
Very hard probes are abundantly produced
Weakly interacting probes become accessible (γ, Z0, W±)
June 2005 8
Alice : required pT reach
Bulk propertiesHard processes
Modified by the medium
ALICEPID
T=QCD Qs
0 1 2 10 100
pt (GeV/c)
June 2005 9
ALICE Physics Reach…
• Global properties• Multiplicities, η distributions
• Degrees of Freedom vs Temperature• Hadron ratios and spectra• Dilepton continuum• Direct photons
• Collective effects• Elliptic flows
• De-confinement• Charmonium, bottonium spectroscopy
• Chiral symmetry restoration• Neutral to charge ratio• Resonance decays
• Partonic energy loss in QGP• Jet quenching, high pT spectra• Open charm and beauty
• Geometry of emission• HBT, zero-degree energy flow
• Fluctuations and critical behavior• Event-by-event particle composition and spectroscopy
June 2005 10
…and experimental consequences for ALICE
• Large Acceptance Coverage• Large Momentum Coverage (from 100 MeV/c to >
100 GeV/c)• High Granularity ( designed for dN/dy ~ 8000, i.e. 15 000 particles in acceptance)
• Spectroscopy and Identification of• hadrons and leptons
• c-, b- vertex recognition• Excellent photon detection ( in Δφ =450 and η = 0.1)
• Large acceptance em calorimetry very desirable, for which only the infrastructure exists, but not yet the detector
June 2005 11
SOUTH AFRICA
UK
PORTUGAL
JINR
GERMANY
SWEDEN
CZECH REP.
HUNGARYNORWAY
SLOVAKIA
POLANDNETHERLANDS
GREECEDENMARK
FINLAND
SWITZERLAND
RUSSIA CERN
FRANCE
MEXICOCROATIA
ROMANIA
CHINA
USA
ARMENIA
UKRAINE
INDIA
ITALY
S. KOREA
0
200
400
600
800
1000
1200
1990 1992 1994 1996 1998 2000 2002 2004
ALICE
Collaboration statistics
LoI
MoU
TP
TRD
•937 members•77 Institutions•Discussion with China, Japan, US
After more than 10 years of life, still healthy and growing!
ALICE collaboration
June 2005 12
ALICE Detector
TPCTPC
PHOSPHOS
Muon armMuon arm
TOFTOF
TRDTRDHMPIDHMPID
PMDPMD
ITSITS
ACCORDEACCORDE
June 2005 13
Stable Layout; Services (Cables, Cooling, Gas…)being installed
June 2005 14
ALICE Detector Suite: selected highlights
• Inner Silicon Tracker • Pixels, Si- Drift, Si- strips
• TPC : the world’s largest• Very ambitious performance specifications• Highly integrated readout electronics
• Transition radiation detector• 1.2*106 channels; trigger capability; (need collaborators for completion;
discussions with Japan)• HMPID : large area RICH with CsI photo-cathodes• FMD: large area Si- multiplicity detector array to complement central
tracking• PHOS : a 20 000 PbWO4 crystal calorimeter (need collaborators for
completion; discussions with China and Japan)• Muon Spectrometer
• with the world’s largest warm dipole• Advanced 1.2*106 channel precision tracker
• Infrastructure for large EM Calorimeter installed• In discussion with US groups
• And, and … arrays of specialized detectors
June 2005 15
Inside the Solenoid for the central detectors; L3 legacy of LEP
June 2005 16
Preparing Space Frame for TPC/ITS/TRD/TOF Pre-Integration
Pre-Integrationof ITS/TPC/TRD/TOFongoing at present moment
June 2005 17
ALICE Layout: Tracking (and event characterization)
Inner Tracking System (ITS):6 Si Layers (pixels, drift, strips)Vertex reconstruction, dE/dx-0.9<<0.9
TRDelectron identification, tracking, dE/dx -0.9<<0.9
TPCTracking, dE/dx-0.9<<0.9
June 2005 18
ALICE Tracking
Combine :ITS + TPC + TRD
June 2005 19
Inner Traking System
Silicon Pixel Detector
ITS = SPD + SSD + SDD
June 2005 20
TPC layout
GAS VOLUME88 m3
DRIFT GAS90% Ne - 10%CO2
Field cage finished
FEE finishedRead out chamber finished
At present pre-integration of field cage into
experimentReadout plane segmentation
18 trapezoidal sectors
each covering 20 degrees in azimuth
EE
510 cm
EE
88us
June 2005 21
TPC principle
ALICE TPC has 88 μs drift timeTRD (2 μs drift only) can serve as trigger for TPC
June 2005 22
Mounting the TPC Central ElectrodeWith 10-4 parallelism to readout chambers
June 2005 23
ALICE TRD : Ionization, Tracklet, Triggering
Pad chambers with a total of 1 200 000 channels
June 2005 24
TRD ; Chamber production in Heidelberg,GSI, Dubna, Bucharest
Chamber production lab in JINR
Electronics and MCM bonding at FZ Karlsruhe
Chamber production in Heidelberg
June 2005 25
TRD prototype
June 2005 26
TRD properties
• TRD will incerase the pion rejection by a factor 100 for e above 3 GeV/c
• TRD’s momentum resolution of 5% at 5 Gev/C will be combied with TPC and ITS
• TRD needs a high granularity in order to cope with the high multiplicity and thus have an acceptable occupancy of about 34% at dN/dy=8000
• Radiation thickness of TRD will be ~ 15% X/X0
June 2005 27
Combined Momentum Resolution
10 100pt (GeV/c)50
p/p
(%
)
10
30
50
resolution ~ 9% at 100 GeV/c excellent performance in hard region!
June 2005 28
ALICE LAYOUT: PID
TOF
PID (K,p,)
-0.9<<0.9
HMPID: High Momentum Particle Identification (, K, p)
June 2005 29
Under study: extension of PID to higher momenta
• Combine TPC and TRD dE/dx capabilities (similar number of samples/track) to get statistical ID in the relativistic rise region
8<p<10GeV/c
June 2005 30
Hadron and Lepton Identification
ALICE PPR CERN/LHCC 2003-049
June 2005 31
• 1 month statistics of PbPb √sNN=5.5 TeV
c/b Quarkonia
Even
ts/1
00 M
eV
103
J/Y
5 10 15
102
dN/d=8000
June 2005 32
Looking forward to first operation
• to a timely completion of LHC and experiments construction in April 2007;• Accelerators and experiments are in the production phase.
• For an exciting decade of HI physics in a new regime physics• Detailed physics program is taking shape ( Physics
Performance Reports, Yellow Report,..)
• The 2005 – 2007 challenge: • Keep the detector construction on its rather tight time scale • Continue preparation and bring to ready-state the physics
analysis programs• demonstrate world-wide distributed Monte-Carlo production
and data analysis.
June 2005 33
Thank you !