QCD matter studies with ALICE ALICE soft physics summary Dariusz Miskowiec, GSI Darmstadt v bulk particle production for the ALICE Collaboration v spatial extension v collective flow v introduction v probing QCD matter v bulk particle production v unexplained ridges in p-A v spatial extension v three questions and answers v collective flow v hard probes v collectivity in small systems? v summary 1
introduction
From the Big Bang to hadrons and nuclei Universe quark-gluon nucleons nuclei atoms plasma today Big Bang 10 –6 s 10 –4 s 3 min 1.4x10 10 y heavy-ion experiments QCD matter studies with ALICE / Dariusz Miskowiec / Bormio 2015 3
heavy-ion collisions UrQMD 160 GeV Au+Au normal nuclear matter ρ 0 = 0.17 /fm 3 • before collision ε 0 = 0.16 GeV/fm 3 • parton collisions initial-state effects • thermalization quark-gluon plasma ε > 0.5 GeV/fm 3 • hadronization • chemical freezeout (number of particles frozen) • kinetic freezeout (particle momenta frozen) QCD matter studies with ALICE / Dariusz Miskowiec / Bormio 2015 4
LHC experiments JURA MOUNTAINS LAKE GENEVA ALICE LHCb CMS ATLAS QCD matter studies with ALICE / Dariusz Miskowiec / Bormio 2015 5
ALICE apparatus SPD SDD SSD T0C V0C ACORDE EMCal HMPID MCH FMD ZDC MTR T0A, V0A PMD TPC ZDC TRD TOF ALICE apparatus: Size : Φ 16 x 26 m Weight : 10,000 tons Collaboration: 1200 members PHOS 131 institutes absorber L3 solenoid dipole 36 countries 6 QCD matter studies with ALICE / Dariusz Miskowiec / Bormio 2015 6
hadron identification QCD matter studies with ALICE / Dariusz Miskowiec / Bormio 2015 7
ALICE performance 2009-2013 arxiv:1402.4476 google for "alice performance" QCD matter studies with ALICE / Dariusz Miskowiec / Bormio 2015 8
ALICE measurements in LHC Run 1 (2009-2013) system sqrt(s NN ) data taking time pp 0.9, 2.36, 2.76, 7, 8 TeV 21 months* Pb-Pb 2.76 TeV 2 x 1 month p-Pb 5.02 TeV 1 month * at a reduced luminosity QCD matter studies with ALICE / Dariusz Miskowiec / Bormio 2015 9
tour through major ALICE results 2009-2013 selected highlights only biased towards soft physics comparison to RHIC (sqrt(s NN ) ≤ 200 GeV, STAR and PHENIX data) QCD matter studies with ALICE / Dariusz Miskowiec / Bormio 2015 10
bulk particle production
charged-particle production: pseudorapidity distributions Pb-Pb p-Pb PRL 110 (2013) 032301 PLB 726 (2013) 610 2200 ALICE 2000 AMPT UrQMD 1800 0-5% CGC based model 1600 5-10% 1400 η 1200 /d 10-20% ch 1000 N d 800 20-30% 600 400 200 constrains initial conditions of heavy-ion collisions 0 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 η models with shadowing or saturation describe the measurement within 20% constrains description of dynamics of heavy-ion collisions saturation models too steep QCD matter studies with ALICE / Dariusz Miskowiec / Bormio 2015 12
charged-particle production: collision energy dependence PRL 110 (2013) 032301 pp (p p ) NSD Central AA 0.15 ß Pb-Pb ∝ s 5 NN ALICE ALICE CMS ATLAS CDF CMS 〉 part 4 UA5 NA50 UA1 BRAHMS N STAR PHENIX 〈 )/ 3 pp (p p ) INEL STAR ß pp, p-Pb η 0.11 ∝ s /d ISR PHOBOS NN ch UA5 N 2 PHOBOS 0.10 ∝ s (d ALICE NN pPb ALICE 1 dAu PHOBOS pAu NA35 0 2 3 10 10 s (GeV) NN ALI − PUB − 46119 p-Pb comparable to pp Pb-Pb about 2 times higher faster growth with collision energy QCD matter studies with ALICE / Dariusz Miskowiec / Bormio 2015 13
Wounded Nucleon Model aka Glauber model aka nuclear overlap calculation à à Npart(b), Ncoll(b), d σ /db Fig.: A. Toia, CERN Courier 26-Apr-2013 For an online calculation: google for "nuclear overlap" QCD matter studies with ALICE / Dariusz Miskowiec / Bormio 2015 14
charged-particle production: centrality dependence PRL 106 (2010) 032301 ~2 times more particles than at RHIC, same centrality dependence QCD matter studies with ALICE / Dariusz Miskowiec / Bormio 2015 15
pion, kaon, proton spectra in Pb-Pb – comparison to RHIC -2 PRL 109 (2012) 252301 ) 6 10 c ) (GeV/ ALICE, Pb-Pb s = 2.76 TeV NN 5 10 STAR, Au-Au, s = 200 GeV NN PHENIX, Au-Au, s = 200 GeV y NN d 3 10 T p /(d N + - + ( 100) π π × 2 d 10 T p + - π K + K ( 10) × 1/2 -1 10 Blast Wave Fit p + p ( 1) × ev VISH2+1 N 1/ HKM -3 10 Kra kow 0-5% Central collisions 0 0 1 2 3 4 5 2 0 1 2 3 4 5 Data/Model proton deficit (compared to p (GeV/ c ) T hydro and thermal models) harder than at RHIC QCD matter studies with ALICE / Dariusz Miskowiec / Bormio 2015 16
Blast-wave parametrization of transverse-momentum spectra Schnedermann, Sollfrank, Heinz, PRC 48(1993)2462 outward collective velocity β T + local kinetic temperature T kin transverse velocity (flow) profile: β T p T spectra: QCD matter studies with ALICE / Dariusz Miskowiec / Bormio 2015 17
identified-hadron spectra – blast-wave fit PRC 88 (2013) 044910 0.2 (GeV) ALICE, Fit Range : 0.5 < p < 1 GeV/ c π 0.18 T K: 0.2 < p < 1.5 GeV/ c T kin 80-90% p: 0.3 < p < 3.0 GeV/ c 0.16 T T 0.14 70-80% 0.12 0-5% 0.1 STAR, Fit Range ALICE Pb-Pb : 0.5 < p < 0.8 GeV/ c 0-5% π √ s = 2.76 TeV 0.08 T K: 0.2 < p < 0.75 GeV/ c (a) T p: 0.35 < p < 1.2 GeV/ c STAR Au-Au 0.06 T √ s = 200 GeV 0.25 0.3 0.35 0.4 0.45 0.5 0.55 0.6 0.65 0.7 〈 β 〉 T 10% more transverse flow than at RHIC QCD matter studies with ALICE / Dariusz Miskowiec / Bormio 2015 18
spatial extension
Bose-Einstein correlation analysis technique (HBT) peak width ~ 1 / source size 1 fm source, simulation pion source size accessible experimentally QCD matter studies with ALICE / Dariusz Miskowiec / Bormio 2015 20
definition of out-side-long axes standard way to parametrize source size in 3-dim QCD matter studies with ALICE / Dariusz Miskowiec / Bormio 2015 21
10 pion HBT in central Pb-Pb collisions (fm) E895 2.7, 3.3, 3.8, 4.3 GeV a) NA49 8.7, 12.5, 17.3 GeV out 8 Phys. Lett. B 696 (2011) 328 (values scaled) R CERES 17.3 GeV 6000 ) 3 (fm E895 2.7, 3.3, 3.8, 4.3 GeV E895 2.7, 3.3, 3.8, 4.3 GeV 6 NA49 8.7, 12.5, 17.3 GeV NA49 8.7, 12.5, 17.3 GeV 5000 long CERES 17.3 GeV CERES 17.3 GeV 4 R STAR 62.4, 200 GeV STAR 62.4, 200 GeV side PHOBOS 62.4, 200 GeV PHOBOS 62.4, 200 GeV 4000 R 2 ALICE 2760 GeV ALICE 2760 GeV out R 3000 0 3/2 (fm) STAR 62.4, 200 GeV b) ) � PHOBOS 62.4, 200 GeV (2 side 8 2000 ALICE 2760 GeV R 6 1000 4 0 0 500 1000 1500 2000 2 dN /d � � � ch 0 (fm) KRAKOW c) homogeneity volume 2 x larger than at RHIC long HKM 8 R AZHYDRO HRM 6 growth with energy reasonably well described by hydro-based models tuned to RHIC data, containing 4 early flow, cross-over, realistic EOS, and hadronic rescattering phase 2 0 0 2 4 6 8 10 12 14 1/3 � dN /d � � ch QCD matter studies with ALICE / Dariusz Miskowiec / Bormio 2015 22
pion HBT in central Pb-Pb collisions Phys. Lett. B 696 (2011) 328 8 8 (fm) (fm) a) b) out side 6 6 R R 4 4 2 2 ALICE Pb-Pb 2.76 TeV STAR Au-Au 200 GeV 0 0 0 0.2 0.4 0.6 0.8 1 0 0.2 0.4 0.6 0.8 1 k (GeV/c) k (GeV/c) � � � � T T 10 (fm) side c) d) 1.4 /R pair transverse momentum long 8 out R R 1.2 6 1 4 0.8 k T dependence – sign KRAKOW HKM of transverse flow 2 0.6 AZHYDRO HRM 0 0.4 0 0.2 0.4 0.6 0.8 1 0 0.2 0.4 0.6 0.8 1 k (GeV/c) k (GeV/c) � � � � T T QCD matter studies with ALICE / Dariusz Miskowiec / Bormio 2015 23
pion HBT in pp collisions PRD 84 (2011) 112004 ALICE pp @ 7 TeV N 1-11 N 17-22 N 37-44 2 ch ch ch N 12-16 N 23-29 N 45-58 ch ch ch N 30-36 N 59-140 ch ch (fm) 1.5 inv R 1 1-dim HBT radius in pair c.m.s. 0.2 0.4 0.6 k (GeV/c) T in pp, a similar k T dependence develops with increasing multiplicity à collective flow in high-multiplicity pp? à QCD matter studies with ALICE / Dariusz Miskowiec / Bormio 2015 24
flow
elliptic flow in Au and Pb collisions centrality 20-30% PRL 105 (2010) 252302 0.08 2 v 0.06 0.04 0.02 ALICE STAR 0 PHOBOS PHENIX -0.02 NA49 CERES v2 -0.04 E877 second Fourier EOS -0.06 coefficient of E895 dN/d( φ - ψ RP ) FOPI -0.08 3 2 4 1 10 10 10 10 s (GeV) NN hydrodynamic behavior continues at LHC energies QCD matter studies with ALICE / Dariusz Miskowiec / Bormio 2015 26
elliptic flow 2 PRL 105 (2010) 252302 v (a) v {2} 40-50% 0.3 2 v {4} 40-50% 2 0.25 v {4} (STAR) 2 0.2 0.15 0.1 0.05 {4} 0 1 2 3 4 5 (b) 10-20% 2 v 20-30% 0.25 30-40% 10-20% (STAR) 0.2 20-30% (STAR) 30-40% (STAR) 0.15 0.1 0.05 0 1 2 3 4 5 p (GeV/ c ) t same p T dependence as at RHIC (and below, down to √ s NN =40 GeV!) inclusive v 2 at LHC higher only because <p T > higher QCD matter studies with ALICE / Dariusz Miskowiec / Bormio 2015 27
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