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Prospects on identified particle correlation in ALICE

Prospects on identified particle correlation in ALICE. Levente Molnar INFN-Bari, KFKI-RMKI. RHIC results on particle ratios. STAR, PRL 97,152301. PHENIX, PRL 91, 172301. Enhanced baryon/meson ratio in 200 GeV Au+Au collisions

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Prospects on identified particle correlation in ALICE

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  1. Prospects on identified particle correlation in ALICE Levente Molnar INFN-Bari, KFKI-RMKI Levente Molnar, INFN-Bari, KFKI-RMKI

  2. RHIC results on particle ratios STAR, PRL 97,152301 PHENIX, PRL 91, 172301 • Enhanced baryon/meson ratio in 200 GeV Au+Au collisions • (Anti-)proton-pion ratio above fragmentation, ... • Limited intermediate pT window Levente Molnar, INFN-Bari, KFKI-RMKI

  3. Soft and hard interplay at RHIC Fries,Muller, PRL90 202303, PRCC 68 044902 • Particle spectra, RCP and particle ratios are “well” described • by soft and hard component models: • Recombination + fragmentation • Hydro + jets • Hydro + pQCD • Soft + quenched Levente Molnar, INFN-Bari, KFKI-RMKI

  4. Soft and hard interplay at LHC Fries R. J.,Müller B. Eur. J. Phys. C 34 S279 LHC: Pb+Pb R.Hwa, PRL97,04230 • The relative soft + hard contribution • changes at higher energies: • Recombination predictions… • How well do we know the hard component? • Measure p+p baseline … Levente Molnar, INFN-Bari, KFKI-RMKI

  5. Contribution of quark and gluon jets in p+p STAR, PLB 637,161 200 GeV S. Albino et al., NPB 597,337 Λ K0 • Missing higher • energy: 630 GeV • PID in jet correlations • Good description at • 200GeV Levente Molnar, INFN-Bari, KFKI-RMKI

  6. Particle correlations at RHIC STAR, nucl-ex/0601042 F.Wang,NPA783,157, L.M. nucl-ex/0701061 • Two particle correlations in the intermediate pT region with trigger particle (4 <pTtrig<6 GeV/c ) exhibit: • broadening of away side correlation • (0.15<pTassoc<4.0 GeV/c) • suppression of high pT particles in • central Au+Au collisions • (2 GeV/c <pTassoc<pTtrig) STAR, 91 (2003) 072304 STAR, 91 (2003) 072304 Mid-rapidity Forward-rapidity Mid-rapidity Levente Molnar, INFN-Bari, KFKI-RMKI

  7. Particle correlations at RHIC II. J.Putschke, QM’06 Au+Au 200GeV 0-10% STAR, nucl-ex/0601042 F.Wang,NPA783,157, L.M. nucl-ex/0701061 • Presence of long range ∆η • correlations • Extends to forward rapidities? • Particle composition of “bulk” and • “ridge”, ongoing effort at RHIC Levente Molnar, INFN-Bari, KFKI-RMKI

  8. Particle correlations at RHIC III. STAR, nucl-ex/0601042 J.Ulery, IWCF’06 M.Ploskon Au+Au Central 0-12% Triggered • Identified particles in the cone region, • similarly to “ridge” measurements N.Ajitanand IWCF’06 Levente Molnar, INFN-Bari, KFKI-RMKI

  9. The ALICE detector ACORDE cosmics FMD ch multiplicity V0, T0 Trigger + multiplicity HMPID PID (RICH) @ high pt TOF PID TRD Electron ID PMD g multiplicity TPC Tracking, dEdx ITS Low pt tracking Vertexing MUON m-pairs PHOS g,p0 • First run setup: • ITS, TPC, MUON • HMPID • 10-15% TRD • 50% ToF EM Calorimeter Levente Molnar, INFN-Bari, KFKI-RMKI

  10. Particle identification in ALICE ALICE PPR II, JPG 32,1295 EMCAL separation @ 3s separation @ 2s • Low magnetic field (0.2-0.5T) • Wide momentum range (tracking): ~ 100 MeV up to >100 GeV • Strong PID capabilities in the central region (|η|<0.9) • Direct hadron PID: (p, K, p) • up to ~ 5 GeV, rdEdx ~ 50 GeV/c • Photons, Leptons • Topological PID up to ~ 20 GeV/c Levente Molnar, INFN-Bari, KFKI-RMKI

  11. Multiplicity at the Tevatron and LHC Probability for an event to have larger than Nch multiplicity (|h|<0.9) T.Nayak, QM’06 W.D.Walker PRD 69, 034007 14TeV 5.5TeV 2.2TeV 900GeV Nch • At LHC: • further multiplicity reach • study multi-parton interactions • dedicated high multiplicity trigger (?) • Increasing cms. energy, broken KNO scaling Levente Molnar, INFN-Bari, KFKI-RMKI

  12. Soft and hard events a la CDF CDF, PRD65, 072005 • EMCAL+tracking (|η|<1.2) • In a cone R = 0.7 define (EMCAL + tracking) • Soft events: • no cluster with ET > 1.1 GeV • Hard events: • ET seed >= 1.0 GeV or track with pT >= 0.7 GeV/c • ET adj. > 0.1 GeV or track with pT > 0.4 GeV/c Levente Molnar, INFN-Bari, KFKI-RMKI

  13. Soft and hard events a la CDF II. CDF, PRD65, 072005 • (CDF) conclusions: • Momentum distribution of “soft” events depends on Nch not on √s • <pT> scales with √s Levente Molnar, INFN-Bari, KFKI-RMKI

  14. Soft and hard events a la CDF III. CDF, hep-ex/0504048 • The soft production of • Λ0 and K0S similar Levente Molnar, INFN-Bari, KFKI-RMKI

  15. High multiplicity trigger D.Elia HMPID ITS/SPD • Enhance high multiplicity events • Limited HMPID : PID acceptance: • fastOR trigger of SPD layers • LHC commissioning … Levente Molnar, INFN-Bari, KFKI-RMKI

  16. Identified particles at Tevatron E735, PRD48,984 STAR, nucl-ex/0607033 B. Hippolyte, EPJ. C49:121-124,2007 • Mapping identified particles • in pT, Nch at each possible • energies. Levente Molnar, INFN-Bari, KFKI-RMKI

  17. Particle correlations at ALICE • Full jet reconstruction possible • event by event: • ETmin ~ 40 GeV • jet fragments: pT ~ 2GeV/c • RHIC results: statistical approach • LHC: • enhanced yield of leading hadrons • but increase in comb. background • How does it look like? Levente Molnar, INFN-Bari, KFKI-RMKI

  18. Charged hadron correlations in ALICE Appelshäuser H and Ploskon M 2005 ALICE-INT-2005-49 • Significant away side at low pTassoc in 5.5TeV PbPb. Levente Molnar, INFN-Bari, KFKI-RMKI

  19. Particle correlations at ALICE • Full jet reconstruction possible • event by event: • ETmin ~ 40 GeV • jet fragments: pT ~ 2GeV/c • RHIC results: statistical approach • LHC: • enhanced yield of leading hadrons • but increase in comb. background • Focus on the near side: full PID for leading and associated particle(s) • ITS+TPC+ToF+TRD (full azimuth, |η|<0.9) • HMPID (57.61º in azimuth, |η|<0.6, track-by-track PID) Levente Molnar, INFN-Bari, KFKI-RMKI

  20. PID Particle correlations at ALICE • Leading particle correlations: • trigger bias, determination of Ejet, • swing of away side parton, … • γ – PID correlations: • measures Ejet, fix direction • low pT limit • Utilize ALICE geometry → PID • PHOS module opposite to HMPID + ITS/TPC/TRD/ToF • Adjacent to EMCAL+PHOS map out the underlying events • PID of leading and assoc. particles: dial q/g jets? • Measure resonance particles Levente Molnar, INFN-Bari, KFKI-RMKI

  21. Summary • RHIC results show a “complicated” intermediate pT region in HI collisions • p+p measurement at the same cms energy are essential baseline to interpret HI collision • PID (γ/h) correlations could provide more refined tools • First data in ~ 8 months … Levente Molnar, INFN-Bari, KFKI-RMKI

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