physics performance of alice

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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

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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 Presentation

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Page 1: Physics Performance of ALICE

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

Page 2: Physics Performance of ALICE

June 2005 2

Heavy Ion Collisions

Page 3: Physics Performance of ALICE

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

Page 4: Physics Performance of ALICE

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

Page 5: Physics Performance of ALICE

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

Page 6: Physics Performance of ALICE

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.

Page 7: Physics Performance of ALICE

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±)

Page 8: Physics Performance of ALICE

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)

Page 9: Physics Performance of ALICE

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

Page 10: Physics Performance of ALICE

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

Page 11: Physics Performance of ALICE

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

Page 12: Physics Performance of ALICE

June 2005 12

ALICE Detector

TPCTPC

PHOSPHOS

Muon armMuon arm

TOFTOF

TRDTRDHMPIDHMPID

PMDPMD

ITSITS

ACCORDEACCORDE

Page 13: Physics Performance of ALICE

June 2005 13

Stable Layout; Services (Cables, Cooling, Gas…)being installed

Page 14: Physics Performance of ALICE

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

Page 15: Physics Performance of ALICE

June 2005 15

Inside the Solenoid for the central detectors; L3 legacy of LEP

Page 16: Physics Performance of ALICE

June 2005 16

Preparing Space Frame for TPC/ITS/TRD/TOF Pre-Integration

Pre-Integrationof ITS/TPC/TRD/TOFongoing at present moment

Page 17: Physics Performance of ALICE

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

Page 18: Physics Performance of ALICE

June 2005 18

ALICE Tracking

Combine :ITS + TPC + TRD

Page 19: Physics Performance of ALICE

June 2005 19

Inner Traking System

Silicon Pixel Detector

ITS = SPD + SSD + SDD

Page 20: Physics Performance of ALICE

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

Page 21: Physics Performance of ALICE

June 2005 21

TPC principle

ALICE TPC has 88 μs drift timeTRD (2 μs drift only) can serve as trigger for TPC

Page 22: Physics Performance of ALICE

June 2005 22

Mounting the TPC Central ElectrodeWith 10-4 parallelism to readout chambers

Page 23: Physics Performance of ALICE

June 2005 23

ALICE TRD : Ionization, Tracklet, Triggering

Pad chambers with a total of 1 200 000 channels

Page 24: Physics Performance of ALICE

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

Page 25: Physics Performance of ALICE

June 2005 25

TRD prototype

Page 26: Physics Performance of ALICE

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

Page 27: Physics Performance of ALICE

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!

Page 28: Physics Performance of ALICE

June 2005 28

ALICE LAYOUT: PID

TOF

PID (K,p,)

-0.9<<0.9

HMPID: High Momentum Particle Identification (, K, p)

Page 29: Physics Performance of ALICE

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

Page 30: Physics Performance of ALICE

June 2005 30

Hadron and Lepton Identification

ALICE PPR CERN/LHCC 2003-049

Page 31: Physics Performance of ALICE

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

Page 32: Physics Performance of ALICE

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.

Page 33: Physics Performance of ALICE

June 2005 33

Thank you !