Heavy Ion Program in ALICE A. Mastroserio Bari University & INFN On behalf of the ALICE collaboration Outline ALICE @ LHC Multiplicity, particle ratios high pt probes Summary and ALICE start up configuration 04/04/2019 A. Mastroserio - XLIIIth Rencontres de Moriond

A. Mastroserio - XLIIIth Rencontres de Moriond ALICE @ LHC ~8.5 km LHC SPS CERN ALICE 04/04/2019 A. Mastroserio - XLIIIth Rencontres de Moriond

A. Mastroserio - XLIIIth Rencontres de Moriond ALICE Setup ALICE Setup ITS HMPID TRD TPC MUON ARM TOF PHOS 04/04/2019 A. Mastroserio - XLIIIth Rencontres de Moriond

Physics topics of ALICE Event characterization Multiplicity, centrality Bulk properties of the hot and dense medium (dynamics of hadronization) hadron ratios, hadronic resonances Chiral symmetry restoration Short lived resonance masses Space-time fireball description and fireball expansion dynamics Momentum correlations (HBT), Radial and anisotropic flow Heavy quark production Charmonium and bottonium (Debye screening, recombination(?)) Partonic energy loss in QGP Jet reconstruction, Jet quenching, high pt spectra, inclusive high pTsuppression, open charm (Mass/color dependence of E loss) Fluctuation phenomena Event-by-Event analysis ……….. 04/04/2019 A. Mastroserio - XLIIIth Rencontres de Moriond

Multiplicity and hadronic yields 04/04/2019 A. Mastroserio - XLIIIth Rencontres de Moriond

A. Mastroserio - XLIIIth Rencontres de Moriond HI Day 1 measurement dNch/dy = 2900 Eskola hep-ph/050649 dNch/dy = 1200 ln(√s) extrapolation ε(RHIC) ~ 15 GeV/fm3 ε(LHC) ~ 3 - 5 x RHIC dNch/dy ~ 1200-2900 ALICE performances tested up to dNch/dη = 8000! 04/04/2019 A. Mastroserio - XLIIIth Rencontres de Moriond

A. Mastroserio - XLIIIth Rencontres de Moriond ALICE performances ALICE PPR Vol II J. Phys. G: Nucl. Part. Phys. 32 (2006) 1295–2040 dNch/dy = 6000 Efficiency (%) pt/pt pt/pt pt/pt ~ 3 % at 100 GeV/c Photon tagging also feasible: direct , π0, η (PHOS) 04/04/2019 A. Mastroserio - XLIIIth Rencontres de Moriond

A. Mastroserio - XLIIIth Rencontres de Moriond Hadronic ratios Statistical models assume a chemical freeze out stage: hadron abundances are fixed. Chemical equilibrium model: depends on two parameters (T, μB) and it is able to describe succesfully hadron yields from SPS to RHIC energies. It predicts a chemical freeze out at LHC energies: A.Andronic, P.Braun-Munzinger, J. Stachel: arXiv:0707.4076v1 [nucl-th] rate of strange (especially multi-strange) hadrons is expected to strongly increase with respect to the equilibrium yields A.Andronic, P. Braun-Munzinger, J. Stachel. Nucl. Phys. A 772: 167-199, 2006 Non-equilibrium scenario: the strangeness phase space is oversaturated (S>1 in the partition function). Tch temperature depends on S and it is lower than the chemical equilibrium prediction. arXiv:0707.4076v1 [nucl-th]. 3 < S < 5 ---> 13 5 < Tch (Mev) < 125 EPJ C49 (2007) 04/04/2019 A. Mastroserio - XLIIIth Rencontres de Moriond

ALICE particle ID performances Unique capability to identify and reconstruct particles - “stable particles” through dE/dx (TPC+ITS) + TOF + Cherenkov (HMPID) π, k, p : 0.15 – 5 GeV/c -> 50 GeV/c (relativistic rise) Invariant mass reconstruction already done for many resonances and strange weak decaying hadrons (K0s, , , ) L Pt limits for 107 central Pb-Pb events (1-year data taking) resolution ~ 1.2 MeV f (1020)  K+K- 04/04/2019 A. Mastroserio - XLIIIth Rencontres de Moriond

A. Mastroserio - XLIIIth Rencontres de Moriond High PT probes 04/04/2019 A. Mastroserio - XLIIIth Rencontres de Moriond

A. Mastroserio - XLIIIth Rencontres de Moriond High PT probes What if QGP is formed: Partons propagate in a hot and dense medium before fragmenting in the vacuum E loss medium > E lossvacuum and depends on the the length of the traversed medium High pT hadrons are suppressed “Jet quenching” -> q [medium dependent] QGP probes: inclusive hadron yields at high pT, Jet Structure 04/04/2019 A. Mastroserio - XLIIIth Rencontres de Moriond

Inclusive hadron yields Factor 5 suppression @RHIC: RAA ~ 0.2 constant at pT > 5 GeV/c Possible LHC scenario: - light flavour RAA - constant ~0.1 at 10< pT (GeV/c) < 20 (gluon dominance) - slow rise up to 0.2 at 20 < pT (GeV/c)< 100 [arXiv:0707.0564v1 [hep-ph] and arXiv:0711.0974v1 [hep-ph] - slow rise to 0.4 up to pT < 400 GeV/c [arXiv:0711.0974v1 [hep-ph] ] Heavy flavour / light flavour RAA : - D quenching vs h quenching probes color charge dependence (ΔEQ < ΔE g) - B quenching vs D quenching probes parton mass dependence of parton E loss 04/04/2019 A. Mastroserio - XLIIIth Rencontres de Moriond

A. Mastroserio - XLIIIth Rencontres de Moriond Jet physics in HI Jet in QCD: cascades of consecutive emissions of partons initiated by partons from an initial hard scattering What if QGP is formed: The initial energy of fast partons is degraded in the medium Broadening of the parton shower along the fast parton direction Modified jet structure and fragmentation functions N. Borghini & U. Wiedemann 04/04/2019 A. Mastroserio - XLIIIth Rencontres de Moriond

Jet Reconstruction: RAA(x) e-by-e jet reconstruction feasible A. Morsch @ QM08 GeV2/fm [AQM] 04/04/2019 A. Mastroserio - XLIIIth Rencontres de Moriond

A. Mastroserio - XLIIIth Rencontres de Moriond Summary ALICE is a versatile experiment which will study the QGP formation in different physics domains (statisical thermodynamics, hydrodynamics, pQCD,etc.) Only few topics of the ALICE Heavy Ion Physics programme have been shown! first 105 events: global event properties multiplicity, rapidity density elliptic flow first 106 events: source characteristics particle spectra, resonances flow analysis interferometry first 107 events: high-pt, heavy flavours jet quenching, heavy-flavour energy loss first 108 events: heavy quark production J/Ψ,  -> initial conditions -> chemical equilibrium -> Parton E loss in the medium 04/04/2019 A. Mastroserio - XLIIIth Rencontres de Moriond

ALICE start up configuration complete – fully installed & commissioned ITS, TPC, TOF, HMPID, MUON SPECTROM., PMD, V0, T0, FMD, ZDC, ACORDE partially completed TRD (25%) to be completed by 2009 PHOS (60%) to be completed by 2010 HLT (30%) to be completed by 2009 EMCAL (0%) to be completed by 2010/11 at start-up full hadron and muon capabilities partial electron and photon capabilities ….looking forward to “detect” this! 04/04/2019 A. Mastroserio - XLIIIth Rencontres de Moriond

A. Mastroserio - XLIIIth Rencontres de Moriond 04/04/2019 A. Mastroserio - XLIIIth Rencontres de Moriond

A. Mastroserio - XLIIIth Rencontres de Moriond Bkp slides 04/04/2019 A. Mastroserio - XLIIIth Rencontres de Moriond

A. Mastroserio - XLIIIth Rencontres de Moriond QGP in lQCD 04/04/2019 A. Mastroserio - XLIIIth Rencontres de Moriond

HI collisions from SPS to LHC Central collisions SPS RHIC LHC sNN (GeV) 17 200 5500 Bj nom(GeV/fm3) 2.9 5 15 (?) QGP(fm/c) <1 1.5-4 4-10 (?) 0(fm/c) 1 0.5 < 0.2 (?) hard/tot ~ 50% ~ 98% Phase transition (lattice QCD): Tcr ~ 170 MeV εcr~ 1 GeV/fm3 New scenario: Hard processes dominate AA cross section QGP at LHC > RHIC : parton dynamics dominate the fireball expansion 04/04/2019 A. Mastroserio - XLIIIth Rencontres de Moriond

A. Mastroserio - XLIIIth Rencontres de Moriond Alice ID 04/04/2019 A. Mastroserio - XLIIIth Rencontres de Moriond

A. Mastroserio - XLIIIth Rencontres de Moriond Hadron ratios Non equilibrium Chemical equilibrium 04/04/2019 A. Mastroserio - XLIIIth Rencontres de Moriond

Strangeness production in HI - No initial net strangeness strange particle are a direct consequence of the collision dynamics Strangeness production mechanism is in the QGP phase: gg-> s sbar (no hadron mass thresholds to be overcome! ) arXiv:0705.2511v1 [nucl-ex] 17 May 2007 04/04/2019 A. Mastroserio - XLIIIth Rencontres de Moriond

A. Mastroserio - XLIIIth Rencontres de Moriond 1 year data taking >107 Jets Background ~ R2 — no pT cut — pT >1 GeV/c — pT >2 GeV/c ETjet 100 GeV 150 GeV 50 GeV 30 GeV R E(R), charged [GeV] 04/04/2019 A. Mastroserio - XLIIIth Rencontres de Moriond

A. Mastroserio - XLIIIth Rencontres de Moriond LHC rates and HQ σ 04/04/2019 A. Mastroserio - XLIIIth Rencontres de Moriond