FrenchSpanish collaboration within the ALICE experiment

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French-Spanish collaboration within the ALICE
experiment
Néstor Armesto Universidade de Santiago de
Compostela, Spain

• Ginés Martínez García
• Subatech, Nantes, France

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Preface

• Experiment at the LHC
• Spanish teams have joined ALICE recently
• Collaboration meeting in Bologna in 2006
• Many topics of common interest have been
  identified
• Spanish contribution reminds modest 1 permanent
  physicist at CIEMAT and 3 physicists of the
  theoretical group from Santiago de Compostela.

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Phases of matter
Phases of matter
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Goal of the HI program

• Understanding of hadron mass in the Standard
  Model - confinement - through the creation of
  extended regions with large energy densities
  (parametric estimates ?4-40 GeV/fm3 for V1000
  fm3).

Complementary to other LHC high-energy studies -
potential for discovering new phenomena at high
energy density - using the same accelerator and
detectors.
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LHC running conditions _at_ P2
Nominal conditions

• Other Heavy-Ion like systems
• pp 5.5 TeV, pPb, lighter ions (O, Ar, Kr, Sn).

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A Large heavy Ion Collider Experiment
y
Side A
z
x
Side C
Inside LHC
LoI LHCC-93-16 (March 1st 1993), TP LHCC 95-71,
TDRs (1997-2008), PPRs JoP G30 11 (2004) JoP
G32 10 (2006), 1st Physics publication expected
in 2009.
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ALICE collaboration

• 1000 members (63 from CERN member states)
• 30 countries
• 100 laboratories
• France MO-2008 member list around 11
• Spain/Cuba MO-2008 member list around 1.

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Topics of common interest

• Hard probes
• Quarkonia and open heavy flavours
• High-pT particles and jets
• Alice computing grid
• Tiers-2 developments
• Future ALICE detector upgrades.

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Quarkonia Physics

• Color screening of the heavy quark potential
• New energy domain at LHC large number of HQ
  pairs
• Measuring upsilon resonances.

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Quarkonia in ALICE

• Heavy quarkonia states, heavy quark production in
  the muon electron channel
• Charmonia from pT0 GeV/c
• Separation of Upsilon states
• Acceptance hlt0.9 -2.5lthlt-4.0
• Potential complications
• Cold nuclear matter effects
• Feed-down from higher resonances
• B-hadron decays.

ALICE muon Spectrometer
Measurement of cc production in proton-proton
collisions via its radiative decay g J/y Item
developed by the CIEMAT group within the PWG3
group.
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cc Analysis

• cc (M3.5GeV) gt
• J/y(M3.1 GeV) g gt ll-g
• Photon detected via external conversion in the
  ALICE TPC

Work in progress Trigger efficiency,
extrapolation to AA. Collaboration with A. Marin,
GSI
P. Ladrón de Guevara et al., Hard Probes
2008 arXiv0811.1592v1 hep-ex
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Energy loss of Heavy Quarks

• Suppression of high-pT particles has been one of
  the golden observations at RHIC
• Interpretation of these data based on the energy
  loss of quarks and gluons crossing the QGP (in
  which Santiago is a leading international group)
  
• At LHC energies, muons will provide a
  non-ambiguous observation of beauty quark energy
  loss.

N. Armesto et al., PRD 71, 054027 (2005).
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Muon distribution at the LHC

• W as a medium blind reference of the beauty Eloss
  in QGP.

Z. Conesa del Valle et al. PLB663, 202 (2008)
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ALICE Computing Grid

• Standard computing Model
• Tier0 (CERN), Tier1, Tier2
• Lower event rate, but larger event size
• Requirements
• CPU 80 MSi2K
• DISK 30 PB
• MSS 40 PB

• France
• 1 Tier1 and 6 Tier2
• Spain
• 1 Tier2

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ALICE Tier2

• Averaged ALICE Tier2
• 1.7 MSI2K CPU and 270 TB disk
• Spain (Tier2 Madrid/Trujillo)
• 0.18 MSI2K CPU and 35 TB disk and 60 TB MSS.

• Potential collaboration
• Development of one new Tier2
• Analysis facilities.

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Other collaborations

• Organization of Conferences
• Contribution of IN2P3 to Hard Probes 2008 and Hot
  Quarks 2008
• European networks of I3HP2 7FP
• JetCal (Jet Physics in HIC)
• ReteQuarkonii (Quarkonia Physics in HIC)
• Other French-Spanish collaborations
• Ecole Polytechnique and LPT Orsay about cold
  nuclear matter effects
• LPTHE Jussieu about jets in heavy ion collisions.

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Future plans

• Reinforcement and extension of the
  collaborations training within EU networks
• Extension of studies of heavy quark energy loss
  to charm
• Studies of jet reconstruction with the TPC EMCAL
  in the heavy ion environment
• Enlargement of the contribution to the
  ALICE-GRID
• Future detector upgrades.

Meeting in2p3 - mcinn, jan 12th 2009, Madrid,
Spain
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