Transcript martinez
The heavy ion collider experiment @
LHC
A L I C E
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 n f =2 T c = 173±8±SysErr MeV n f =3 T c = 153±8±SysErr MeV e c = 700 ± 300 MeV Ginés MARTINEZ, SUBATECH • QCD-thermodynamics • Properties of the QGP and of the phase transition: – Chiral transition – Deconfinement 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?
Collision dynamics Ginés MARTINEZ, SUBATECH 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 Ginés MARTINEZ, SUBATECH Rencontres de Moriond March 17-24 2001 The QGP phase 5
Why HI program @
LHC
?
Central collisions SPS s 1/2 (GeV) dN ch /dy e (GeV/fm 3 ) V f (fm 3 ) t QGP (fm/c) t 0 (fm/c) 17 500 2.5
10 3 <1 ~1 RHIC 200 700-1500 LHC 5500 3-8 x10 3 3.5-7.5
7x10 1.5-4.0
~0.5
@ LHC : Hotter – bigger - longer Ginés MARTINEZ, SUBATECH Rencontres de Moriond March 17-24 2001 3 15-40 2x10 4 4-10 <0.2
J. Schukraft QM2001
6
The gluon-gluon physics…
• Gluon distribution in nuclei grows for small values of x = 2p T /s 1/2 and high gluon densities are reached .
• For high densities ( r T >> L 2 QCD ) 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/e c ~ 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 8
Final state probes
• Forward energy • dN/dy • hadron pT distribution • Particle ratios • Strange particles
Pb+Pb @ 5.5A TeV
Ginés MARTINEZ, SUBATECH -1< h <1 • Multiplicity • Energy Density • HBT and dynamical evolution • Freeze-out temperature • Fluctuations • Collective motion • 12200 • 700 • …. h p ’s • 1700 K’s ’s • 570 p, n, p, n ‘s Rencontres de Moriond March 17-24 2001 9
Penetrating probes
• • Real and virtual photons • Quarkonia: J/ Y &
Y Open Charm & Beauty
• • Light vector mesons
Jets
• Initial stage • Thermal radiation: T ini • Colour screening of heavy quarks • Jet-matter interaction • Chiral transition Ginés MARTINEZ, SUBATECH Rencontres de Moriond March 17-24 2001 10
Jet Matter interaction
1-3 GeV/fm B # Dt 0 A Large production of jets @ LHC energies 1 jet/GeV/s in the ALICE acceptance at E T =50 GeV Looking for Jet matter interaction: g 1. High p T particle distributions 2. Identification of jets … 3. Tagging with photons: • High p T particles • Jets # Interference with vacuum and LPM, Jet enhancement E jet dependence of D E p T > 10 – 20 GeV Ginés MARTINEZ, SUBATECH
Urs. Wiedemann QM2001 et NPB588(00)203
Rencontres de Moriond March 17-24 2001 11
Building
ALICE
• Event Characterisation • dN ch /dy • pT distribution • Particle ratios • Strange baryons • Fluctuations • Light vector mesons • Quarkonium • Open charm & beauty • Photon & Dilepton • Jet quenching • … Ginés MARTINEZ, SUBATECH Rencontres de Moriond March 17-24 2001 12
dN
ch
/d
h Dh =1
~ 8000
• Time Projection Chamber:
Main tracking detector of ALICE central barrel
• Inner radius: Track separation R in = 0.8 m • Outer radius: dE/dx & p resolution # R out = 2.5 m • Large acceptance Dh <0.9
• 200Hz rate capability • MWPC read-out 32 m 2 , 40% Oc • 5 10 5 pads x 500 time bins • 60 Mbyte/evt => DC, RoI, L3 … Tracking efficiency ~90% 2 tracks eff. 80%
TPC
D p>15 MeV/c 5 m
Ne+CO 2 (10%)
# Magnetic field of the L3 magnet 0.4T
5% @ 5 GeV/c Ginés MARTINEZ, SUBATECH 1. PID below ~600 MeV/c 2. Low Rencontres de Moriond March 17-24 2001 D p tracks 13
The
ALICE
PID
• 0.5 < p < 5 GeV/c • e, p , K, p pT distributions •Particles ratios: T freeze-out •Fluctuations •Strangeness production •Light vector mesons •Open charm •Jet physics Ginés MARTINEZ, SUBATECH Time of Flight High Momentum Particle Identification Transition Radiation Detector ToF prototype
ToF
• • • Large acceptance • MRPC s = 150 ps p ,K,p • 0.5 Multigap Resistive Plate Chamber Rencontres de Moriond March 17-24 2001 10cm 14 High Momentum PID: • Hard processes 1 GeV/c < p < 5 GeV/c Rich-imaging technique Small acceptance 7x Ginés MARTINEZ, SUBATECH Rencontres de Moriond March 17-24 2001 15 • J/ • Open charm normalization • J/ Y Y in Zero baryon density source from Open Beauty • D annihilation? • G production • Light vector resonances: f, w e channel • Electron detector • 10 -3 pion rejection • Large acceptance • Transition Radiation Detector Pb+Pb central collisions 6x g ~ 10 3 E X ~ 3-30 KeV Ginés MARTINEZ, SUBATECH Rencontres de Moriond March 17-24 2001 16 resolution • Strangelets p • Secondary vertex from hyperon decays • Open charm & beauty physics • Tracking of low pT particles • Improving momentum W - L K p I T S • • Large acceptance • 15000 tracks s ~100 m m in r f 6 Silicon layers: 1. 2. 3. 2 Silicon Pixel layers 2 Silicon Drift layers 2 Silicon Strip layers Ginés MARTINEZ, SUBATECH D =>K p 10 7 evt Rencontres de Moriond March 17-24 2001 17 10 1 0.1 5% • Thermal radiation • High p t physics • Tagged jets • 1200 g p T >40 GeV/c hep-ph/9906325 1 2 3 4 p T (GeV/c) • EM calorimeter • PbWO4: spectrometer: p 0 ,h • Small acceptance 0.07 DhDf/2p • 1< p T • 5< p T < 5 GeV/c <100 GeV/c 5x PHOS Module Ginés MARTINEZ, SUBATECH Rencontres de Moriond March 17-24 2001 18 Quarkonium physics: J/ Y and Y families s ~ 100 MeV 2.4 < h < 4.0 Ginés MARTINEZ, SUBATECH e m coin.: •Intermediate rapidity •DD, BB production Rencontres de Moriond March 17-24 2001 19 + PMD FMD CASTOR ZDC Trigger DAQ Offline Ginés MARTINEZ, SUBATECH Rencontres de Moriond March 17-24 2001 20 • Pb+Pb @ 5.5A TeV • 10 6 s per year • 8000 Hz (L=10 27 cm -2 s -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 • • • • HI in LHC: a rigorous step towards the QGP physics – Perturbative + weak coupling methods – Direct partonic probes: Jets. The LHC HI dedicated experiment: ALICE – 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 Ginés MARTINEZ, SUBATECH Rencontres de Moriond March 17-24 2001 Quark Matter 2002 in Nantes 23High momentum particles
HMPID
Electron Identificator of ALICE
TRD
Primary and secondary Vertex Position
ITS
Photon detection
PHOS
Di muon channel
DiMuon
ALICE = The result of QGP physics requirements at LHC
Running conditions
conclusions
A new research domain