prospects on identified particle correlation in alice
DESCRIPTION
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 - PowerPoint PPT PresentationTRANSCRIPT
Levente Molnar, INFN-Bari, KFKI-RMKI
March, 2007, Jyväskylä 1
Prospects on identified particle correlation in ALICE
Levente MolnarINFN-Bari, KFKI-RMKI
Levente Molnar, INFN-Bari, KFKI-RMKI
March, 2007, Jyväskylä 2
RHIC results on particle ratiosPHENIX, PRL 91, 172301
• Enhanced baryon/meson ratio in 200 GeV Au+Au collisions • (Anti-)proton-pion ratio above fragmentation, ...• Limited intermediate pT window
STAR, PRL 97,152301
Levente Molnar, INFN-Bari, KFKI-RMKI
March, 2007, Jyväskylä 3
Soft and hard interplay at RHIC
• Particle spectra, RCP and particle ratios are “well” described by soft and hard component models:
• Recombination + fragmentation• Hydro + jets• Hydro + pQCD• Soft + quenched
Fries,Muller, PRL90 202303, PRCC 68 044902
Levente Molnar, INFN-Bari, KFKI-RMKI
March, 2007, Jyväskylä 4
Soft and hard interplay at LHC
• The relative soft + hard contribution changes at higher energies:
• Recombination predictions…
• How well do we know the hard component?
• Measure p+p baseline …
Fries R. J.,Müller B. Eur. J. Phys. C 34 S279
LHC: Pb+PbR.Hwa, PRL97,04230
Levente Molnar, INFN-Bari, KFKI-RMKI
March, 2007, Jyväskylä 5
Contribution of quark and gluon jets in p+p
• Good description at 200GeV
200 G
eV
STAR, PLB 637,161
Λ K0
S. Albino et al., NPB 597,337
• Missing higher energy: 630 GeV
• PID in jet correlations
Levente Molnar, INFN-Bari, KFKI-RMKI
March, 2007, Jyväskylä 6
Particle correlations at RHICSTAR, nucl-ex/0601042
Two particle correlations in the intermediate pT region with trigger particle (4 <pT
trig<6 GeV/c ) exhibit:
• broadening of away side correlation (0.15<pT
assoc<4.0 GeV/c)
• suppression of high pT particles in central Au+Au collisions (2 GeV/c <pT
assoc<pTtrig)F.Wang,NPA783,157, L.M. nucl-ex/0701061
Mid-rapidity Forward-rapidity Mid-rapidity
STAR, 91 (2003) 072304 STAR, 91 (2003) 072304
Levente Molnar, INFN-Bari, KFKI-RMKI
March, 2007, Jyväskylä 7
Particle correlations at RHIC II.
• Presence of long range ∆η correlations
• Extends to forward rapidities?
• Particle composition of “bulk” and “ridge”, ongoing effort at RHIC
STAR, nucl-ex/0601042
F.Wang,NPA783,157, L.M. nucl-ex/0701061
J.Putschke, QM’06
Au+Au 200GeV0-10%
Levente Molnar, INFN-Bari, KFKI-RMKI
March, 2007, Jyväskylä 8
Particle correlations at RHIC III.STAR, nucl-ex/0601042
Au+Au Central 0-12% Triggered
J.Ulery, IWCF’06
N.Ajitanand IWCF’06• Identified particles in the cone region, similarly to “ridge” measurements
M.Ploskon
Levente Molnar, INFN-Bari, KFKI-RMKI
March, 2007, Jyväskylä 9
ITSLow pt trackingVertexing
ITSLow pt trackingVertexing
TPCTracking, dEdxTPCTracking, dEdx
TRDElectron IDTRDElectron ID
TOFPIDTOFPID
HMPIDPID (RICH) @ high pt
HMPIDPID (RICH) @ high pt
PHOS,0 PHOS,0
MUON -pairs MUON -pairs
PMD multiplicityPMD multiplicity
V0, T0Trigger + multiplicity
ACORDEcosmics
FMDch multiplicityFMDch multiplicity
EM Calorimeter
The ALICE detector
First run setup:• ITS, TPC, MUON• HMPID• 10-15% TRD• 50% ToF
Levente Molnar, INFN-Bari, KFKI-RMKI
March, 2007, Jyväskylä 10
• 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)
Particle identification in ALICE
• Direct hadron PID: (p, K, p) up to ~ 5 GeV, rdEdx ~ 50 GeV/c
• Photons, Leptons
• Topological PID up to ~ 20 GeV/c
separation @ 3 separation @ 2
EMCAL
ALICE PPR II, JPG 32,1295
Levente Molnar, INFN-Bari, KFKI-RMKI
March, 2007, Jyväskylä 11
Multiplicity at the Tevatron and LHCW.D.Walker PRD 69, 034007
• Increasing cms. energy, broken KNO scaling
Nch
900GeV
14TeV5.5TeV
2.2TeV
Probability for an event to have larger than Nch multiplicity
(||<0.9)
T.Nayak, QM’06
At LHC: • further multiplicity reach• study multi-parton interactions• dedicated high multiplicity trigger (?)
Levente Molnar, INFN-Bari, KFKI-RMKI
March, 2007, Jyväskylä 12
Soft and hard events a la CDF
• 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
CDF, PRD65, 072005
Levente Molnar, INFN-Bari, KFKI-RMKI
March, 2007, Jyväskylä 13
Soft and hard events a la CDF II.
(CDF) conclusions:
• Momentum distribution of “soft” events depends on Nch not on √s
• <pT> scales with √s
CDF, PRD65, 072005
Levente Molnar, INFN-Bari, KFKI-RMKI
March, 2007, Jyväskylä 14
Soft and hard events a la CDF III.
CDF, hep-ex/0504048
• The soft production of Λ0 and K0
S similar
Levente Molnar, INFN-Bari, KFKI-RMKI
March, 2007, Jyväskylä 15
High multiplicity trigger
D.Elia
ITS/SPD
HMPID
• Enhance high multiplicity events
• Limited HMPID : PID acceptance: fastOR trigger of SPD layers
• LHC commissioning …
Levente Molnar, INFN-Bari, KFKI-RMKI
March, 2007, Jyväskylä 16
Identified particles at Tevatron
E735, PRD48,984
B. Hippolyte, EPJ. C49:121-124,2007 STAR, nucl-ex/0607033
• Mapping identified particles in pT, Nch at each possible energies.
Levente Molnar, INFN-Bari, KFKI-RMKI
March, 2007, Jyväskylä 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
March, 2007, Jyväskylä 18
Charged hadron correlations in ALICE
• Significant away side at low pTassoc in 5.5TeV PbPb.
Appelshäuser H and Ploskon M 2005 ALICE-INT-2005-49
Levente Molnar, INFN-Bari, KFKI-RMKI
March, 2007, Jyväskylä 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
March, 2007, Jyväskylä 20
PID Particle correlations at ALICELeading 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
March, 2007, Jyväskylä 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 …