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Physics Reach

Physics Reach. Christoph Blume University of Frankfurt/Main for the ALICE Collaboration. ALICE physics Strongly interacting matter Observables p+p physics The ALICE experiment Running conditions for Pb+Pb and p+p running Acceptance Tracking performance

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Physics Reach

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  1. Physics Reach Christoph Blume University of Frankfurt/Main for the ALICE Collaboration

  2. ALICE physics Strongly interacting matter Observables p+p physics The ALICE experiment Running conditions for Pb+Pb and p+p running Acceptance Tracking performance Particle identification Low pt physics examples Heavy quarks Open charm Open beauty Quarkonia family Parton energy loss High pt particle spectra Jets via correlations Physics ReachOutline Christoph Blume, LHC Symposium 2003, May 1-3, Fermi National Accelerator Lab.

  3. Exploring the phase diagram of strongly interacting matter LHC provides access to the high T, vanishing mB QGP phase LHC ALICE Physics Phases of Strongly Interacting Matter Lattice QCD, mB = 0 Christoph Blume, LHC Symposium 2003, May 1-3, Fermi National Accelerator Lab.

  4. Initial conditions Hard processes Probe of early state of reaction Pertubative QCD Significant part of cross section High density parton distributions Bulk of partons at x 10-3 Saturated gluon densities Classical QCD: QsA1/3/ xd Evolution of system will be dominated by partons Longer lifetime of QGP phase Collective effects will be strongly influenced by parton dynamics  partonic flow ALICE PhysicsProperties of QGP Phase @ LHC Christoph Blume, LHC Symposium 2003, May 1-3, Fermi National Accelerator Lab.

  5. ALICE PhysicsObservables Jets Open charm, beauty Christoph Blume, LHC Symposium 2003, May 1-3, Fermi National Accelerator Lab.

  6. Soft Regimept = 0–2 GeV/c non-perturbative Particle yields chem. freeze-out HBT interferometry thermal freeze-out Flow expansion ALICE PhysicsObservables Semi-hard Regimept = 2–5/10 GeV/c • Thermal photons  temp. evolution • Open charm, J/Y plasma screening • pt-Spectra mini-jets Hard Regimept > 10 GeV/c perturbative • Hard photons • Open beauty, U • Jets  initial collisions • ALICEwill cover the transition from the soft (hadronic) to the hard (partonic) regime • Correlations between soft and hard probes only possible within ALICE Christoph Blume, LHC Symposium 2003, May 1-3, Fermi National Accelerator Lab.

  7. Benchmark for Pb+Pb: Multiplicities (strangeness) J/Y and U Parton energy loss (jets) Thermal photons High energy densities @ LHC: e 1.2 GeV/fm3 Comparable to N+N @ SPS/RHIC Bulk of cross section at low pt Investigation in a new energy regime p+A program Nuclear structure functions Benchmark for Pb+Pb ALICE Physicsp+p Physics Christoph Blume, LHC Symposium 2003, May 1-3, Fermi National Accelerator Lab.

  8. HMPID PID (RICH) @ high pt TOF PID, talk by C. Williams TRD Electron ID PMD g multiplicity TPC Tracking, dEdx ITS Low pt tracking Vertexing MUON m-pairs talk by A. Morsch PHOS g,p0 The ALICE Experiment Christoph Blume, LHC Symposium 2003, May 1-3, Fermi National Accelerator Lab.

  9. Large charged multiplicity Estimates quite uncertain Design for dNch/dy|max = 8000 Luminosity: Lmax = 11027 cm-2s-1 Event rate: 8000 minimum bias coll./ s ~109 events/year 1% collected Trigger for low cross section observables MUON, PIXEL, PHOS, TRD High-Level Trigger (HLT) The ALICE ExperimentRunning conditions for Pb+Pb Christoph Blume, LHC Symposium 2003, May 1-3, Fermi National Accelerator Lab.

  10. The ALICE ExperimentEvent Display Pb+Pb HMPID TOF TRD TPC 60 < J < 62! PHOS Christoph Blume, LHC Symposium 2003, May 1-3, Fermi National Accelerator Lab.

  11. “Low“ luminosity: Lmax = 2-5  1030 cm-2 s-1 Event pile-up TPC drift 88 ms On average 25 events (for Lmax = 2  1030 cm-2 s-1) Pile-up can be removed with High-Level Trigger Reduction in data volume:  factor 5 Short run periods with ‘‘ultra-low‘‘ luminosity  no pile-up Lmax  1029 cm-2 s-1 The ALICE Experimentp+p Running Conditions Christoph Blume, LHC Symposium 2003, May 1-3, Fermi National Accelerator Lab.

  12. The ALICE ExperimentAcceptance Central Barrel Christoph Blume, LHC Symposium 2003, May 1-3, Fermi National Accelerator Lab.

  13. Reconstruction efficiency dNch/dy = 8000, B = 0.4T 98% in TPC Acceptance at high pt: ~90% Momentum resolution: dNch/dy = 8000, B = 0.4T Combined tracking ITS+TPC+TRD 9% (pt = 100 GeV/c) The ALICE ExperimentTracking Performance TPC primary tracks  9% Christoph Blume, LHC Symposium 2003, May 1-3, Fermi National Accelerator Lab.

  14. For heavy-ion collisions Large track statistics Resolution in bending projection: 10–15 mm (beam spot 15 mm) Resolution in non-bending projection: better than 10 mm For p+p collisions Low track statistics Effect on charm measurement The ALICE ExperimentMain Vertex Determination p+p Christoph Blume, LHC Symposium 2003, May 1-3, Fermi National Accelerator Lab.

  15. TPC dE/dx resolution: 6.8% for dN/dy = 8000 5.3% for dN/dy = 800 ITS dE/dx (a.u.) dE/dx HMPID Prototype in STAR Momentum Momentum (GeV/c) The ALICE ExperimentParticle Identification Christoph Blume, LHC Symposium 2003, May 1-3, Fermi National Accelerator Lab.

  16. The ALICE ExperimentPID Summary Christoph Blume, LHC Symposium 2003, May 1-3, Fermi National Accelerator Lab.

  17. Single event Raw correlation function Uncorrected for Coulomb R = 8 fm, l = 0.5 Tracking with ITS+TPC, B = 0.2T Low pt Physics ExamplesEvent-by-Event p+p+ HBT C(Qinv) Qinv (GeV) Christoph Blume, LHC Symposium 2003, May 1-3, Fermi National Accelerator Lab.

  18. Decay channel K* K+p- Invariant mass distribution for 550 events Low pt Physics ExamplesResonances: K* Entries M(K+p-) (GeV/c2) Christoph Blume, LHC Symposium 2003, May 1-3, Fermi National Accelerator Lab.

  19. Heavy quarks probe dynamics of whole QGP phase Perturbative in intial collisions Thermal production in QGP Direct measurement of heavy flavour in p+p and A+A mandatory Quarkonia (J/Y and U states) Binding energy in the order of mean energy in QGP Sensitive to screening effects Aim: correlation of heavy quark and quarkonia production as function of pt Heavy Quarks Uncertainty of factor  4 in predictions for pp @ LHC • Quarkonia m+m-: MUON • Quarkonia  e+e-: TPC+TRD • D  Kp, ITS+TPC+TOF • Semileptonic decays of D + B: ITS+TPC+TRD and MUON • DD (BB) via em coincidences: TRD+MUON Christoph Blume, LHC Symposium 2003, May 1-3, Fermi National Accelerator Lab.

  20. Heavy QuarksOpen Charm via Hadronic Decays cuts depend on D0pt D0 K-p+ ct = 123.7  0.8 mm BR: (3.83  0.09) % Affected by main vertex resolution in p+p case Christoph Blume, LHC Symposium 2003, May 1-3, Fermi National Accelerator Lab.

  21. Input to simulation cc: PYTHIA, tuned to NLO calculations, with CTEQ4L and nuclear shadowing EKS98 Background: HIJING Reconstruction effects included PID with TOF Heavy QuarksOpen Charm via Hadronic Decays Pb+Pb sminv = 12 MeV (B = 0.4T) Christoph Blume, LHC Symposium 2003, May 1-3, Fermi National Accelerator Lab.

  22. Heavy QuarksOpen Charm via Hadronic Decays Pb+Pb: pt > 1 GeV/c Significance dN/dpt p+p: pt > 0 GeV/c ! Significance = Significance dN/dpt Christoph Blume, LHC Symposium 2003, May 1-3, Fermi National Accelerator Lab.

  23. B  e- + X Electron ID in TPC + TRD Cuts: Impact parameter d0 Electron pt Heavy QuarksOpen Beauty via Semileptonic Decays Entries (a.u.) d0 (mm) pt > 2 GeV/c + d0 > 150 mm: 5-10·104 e with S/(S+B) = 90 % Christoph Blume, LHC Symposium 2003, May 1-3, Fermi National Accelerator Lab.

  24. Heavy QuarksJ/Y and U via Dielectrons J/Y: Mass resolution for U: 100 MeV (B = 0.4T) U: Acceptance down to pt = 0! Christoph Blume, LHC Symposium 2003, May 1-3, Fermi National Accelerator Lab.

  25. B J/Y e+e- (BR: 1%) Large contribution to observable J/Y signal Possibility to disentangle primary and secondary J/Ys Heavy QuarksSecondary J/Y from B Meson Decays J/Y from B decays Impactparameter Christoph Blume, LHC Symposium 2003, May 1-3, Fermi National Accelerator Lab.

  26. Parton Energy Loss Christoph Blume, LHC Symposium 2003, May 1-3, Fermi National Accelerator Lab.

  27. Medium induced gluon radiation Depends on traversed distance  L2 Stronger in deconfined matter Effects: Reduction of single inclusive high pt particles Parton specific (stronger for gluons than quarks) Flavour specific (stronger for light quarks) Measure identified hadrons (p, K, p, L, etc.) + partons (charm, beauty) at high pt Suppression of mini-jets same-side / away-side correlations Change of fragmentation function for hard jets (pt >> 10 GeV/c) Transverse and longitudinal fragmentation function of jets Jet broadening  reduction of jet energy, dijets, g-jet pairs p+p and p+A measurements crucial Parton Energy Loss Christoph Blume, LHC Symposium 2003, May 1-3, Fermi National Accelerator Lab.

  28. RAA clearly different between mesons and baryons Importance of PID at high pt p+p baseline measurement! High ptRHIC Results Christoph Blume, LHC Symposium 2003, May 1-3, Fermi National Accelerator Lab.

  29. Estimates for the pt limit in one year ALICE running 107 Pb+Pb events 109 p+p events p+p simulation PYTHIA 6.210 + CTEQ5L (default tuning) High ptMinimum Bias Pb+Pb and p+p Scaled to 107 Pb+Pb min. bias events dN/dpt ~2103 tracks pt > 50 GeV/c High pt trigger (TRD, HLT) will extend pt range to > 100 GeV/c pt (GeV/c) N( pt) 109 p+p events: 103 tracks with pt  40 GeV/c 104 rec. p+p evts. pt (GeV/c) Christoph Blume, LHC Symposium 2003, May 1-3, Fermi National Accelerator Lab.

  30. One year of ALICE running (107 events)  Ls up to pt = 12 GeV/c Can be improved using PID for L daughters High ptIdentified Particles: L % % of rec. Ls vs pt S/B  1 5.5 L/event pt (GeV/c) Entries L Yield Reconstructed pt spectrum M(pp) (GeV/c2) pt (GeV/c) Christoph Blume, LHC Symposium 2003, May 1-3, Fermi National Accelerator Lab.

  31. Inclusive g: Direct + p0 Directg High ptIdentified Particles: g+p0 without high-pt trigger for 107 events with high-pt trigger dN/dpt dN/dpt Inclusive g: Direct + p0 Directg pt (GeV/c) pt (GeV/c) • Separationofg/p0 and p0detection up to 100 GeV/c • Statistically for low pt (< 30-40 GeV/c) • E-by-E at higher pt (> 30-40 GeV/c) Christoph Blume, LHC Symposium 2003, May 1-3, Fermi National Accelerator Lab.

  32. Transformation d2N/dfdh  1/R dN/dR with: R2 = Dh2 + Df2 1000 HIJING events (default) Jets in Pb+PbCorrelations with Leading Particle pt(seed) = 5 GeV/c pt > 3 GeV/c 1 < R < 2 1/R dN/dR R < 0.3 pt (GeV/c) R Christoph Blume, LHC Symposium 2003, May 1-3, Fermi National Accelerator Lab.

  33. Correlation increases with pt Effect of gluon radiation System size dependence p+p Jets in Pb+PbTwo Particle Correlations Christoph Blume, LHC Symposium 2003, May 1-3, Fermi National Accelerator Lab.

  34. ALICE physics reach extends from: Low pt > 0.1 GeV/c Identified particles Correlations, HBT Event-by-event observables Flow to: High pt ~ 100 GeV/c Heavy quarks Quarkonia Photons Jets p+p and p+A physics Baseline for A+A Important physics on its own Integral part of ALICE physics program Physics Performance Report Full simulations for all projected physics observables Summary Christoph Blume, LHC Symposium 2003, May 1-3, Fermi National Accelerator Lab.

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