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High Energy Density Quantum Chromo-Dynamics Frontier at LHC-ALICE

Discover the latest research at the intersection of high-energy density Quantum Chromo-Dynamics (QCD) and particle physics, focusing on ALICE experiments probing the QCD phase diagram and emerging phenomena. Learn about novel findings, thermal photon strategies, and ALICE's contributions to understanding the early Universe and new states of matter. Dive into the world of high-energy nucleus accelerators and the key outcomes from the RHIC collider. Explore exciting news from RHIC and LHC, including the measurement of temperatures above critical thresholds. Delve deeper into the realm of relativistic heavy ion collisions, photon production mechanisms, and the significance of thermal photons as thermometers of matter states. 8 Relevant

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High Energy Density Quantum Chromo-Dynamics Frontier at LHC-ALICE

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  1. High Energy DensityQuantum Chromo-Dynamics Frontierat LHC-ALICE Kenta Shigaki (Hiroshima University ) for theALICE Collaboration GCOE Symposium “Emerging Frontiers of Physics” February 23, 2011 Kyoto University

  2. Presentation Outline • experimental expeditions on QCD phase diagram • two exciting news • temperature well above the boundary at RHIC • newly started LHC/ALICE physics programs • ALICE first physics results from p+pand Pb+Pb • thermometer at ALICE • thermal photon strategies, feasibilities, prospects • summary and concluding remarks Emerging Frontiers of Physics – High Energy Density QCD Frontier at ALICE – K.Shigaki

  3. Goals of High Energy Nuclear Physics • why nucleus-nucleus at GeV/TeV range? • “system” of particles under strong QCD field • cf. “processes” between elementary particles • state of matter at ~ 10-5 seconds after Big Bang • cf. production/interaction of matter at ~ 10-12 seconds • hadronic mass generation via confinement • cf. particle mass generation via Higgs mechanism Emerging Frontiers of Physics – High Energy Density QCD Frontier at ALICE – K.Shigaki

  4. Expeditions on QCD Phase Diagram High Energy A+A Collisions • toward deconfined partonic phase • lattice Quantum Chromo-Dynamics predictions • critical temperature ~ 170 MeV • critical energy density ~ 1 GeV/fm3 Early Universe DeconfinedPartonic Phase (Quark-Gluon Plasma) Energy Density (Temperature) Tri-Critical Point Critical Temperature ~ 170 MeV Color Super-Conductivity Hadron Gas Color-Flavor Locking F. Karsch, Lect. Notes Phys. 583 (2002) 209 Neutron Star? Nucleus Baryon Density Emerging Frontiers of Physics – High Energy Density QCD Frontier at ALICE – K.Shigaki

  5. High Energy Nucleus Accelerators • from Bevalac/SIS/AGS/SPS to RHIC/LHC • from high density to high energy density regime • recent major facilities • BNL-AGS (11 A GeV 197Au + fixed target) • 28Si since 1986, 197Au since 1991; programs terminated • CERN-SPS (200 A GeV 208Pb + fixed target) • 32S since 1986, 208Pb since 1994; programs terminated • BNL-RHIC (100 + 100 A GeV 197Au + 197Au) • since 2000; in operation • CERN-LHC (2.8 + 2.8 A TeV 208Pb + 208Pb) • since 2009; in operation Emerging Frontiers of Physics – High Energy Density QCD Frontier at ALICE – K.Shigaki

  6. Two Exciting News from RHIC/LHC • temperature above Tc measured at RHIC • Phys.Rev.Lett. 104, 132301 (2010) • Phys.Rev.C 81, 034911 (2010) • new energy regime at ALICE/LHC • 900 GeV, 2.36 TeV, 7 TeV p+p in 2009–2010 • 2.76 TeV Pb+Pb in 2010 • higher statistics runs in 2011–2012 Emerging Frontiers of Physics – High Energy Density QCD Frontier at ALICE – K.Shigaki

  7. Relativistic Heavy Ion Collider at BNL • 2 independent super-conducting synchrotrons • up to 100 A GeV Au and/or 250 GeV (polarized) p • Au+Au/Cu+Cu/d+Au/p+p/… • 4 (2 presently) complimentary experiments Emerging Frontiers of Physics – High Energy Density QCD Frontier at ALICE – K.Shigaki

  8. RHIC Outcomes: New State of Matter • partonic: quarks’ degrees of freedom, screening • constituent quark number scaling of collective motion • J/Y suppression • dense: energy loss of (even heavy) quarks • jet quenching (high pT suppression) • jet modification • strongly coupled: perfect fluidity • hydro-dynamical collective motion • hot: thermally radiative • thermal (virtual) photons The matter is dense The matter is strongly coupled The matter may melt and/or regenerate J/y’s The matter modifies jets The matter is hot Emerging Frontiers of Physics – High Energy Density QCD Frontier at ALICE – K.Shigaki

  9. Photons as Thermometer • thermal radiation if in equilibrium • emission spectrum  temperature • real and virtual thermal photons Emerging Frontiers of Physics – High Energy Density QCD Frontier at ALICE – K.Shigaki

  10. Photon Production in HI Collisions Hadronization (Freeze-out) + Expansion Thermalization QGP phase? Mixed phase Pre-equilibrium Thermal Photon (QGP) Thermal Photon (HG) Jet-Photon Conversion Jet-Bremsstrahlung (QGP) Jet+Medium Compton/Annihillation Fragmentation Prompt Photon Thermal Photon Time Evolution Emerging Frontiers of Physics – High Energy Density QCD Frontier at ALICE – K.Shigaki

  11. Where to Catch Thermal Photons g q g q p p r g • high pT: pQCD photons • low pT: photons from hadronic gas • intermediate pT: QGP thermal photons dominant ! • also other sources • plus hadron decay photons everywhere hadron decay photons S.Turbideet al., PRC 69 014903 Emerging Frontiers of Physics – High Energy Density QCD Frontier at ALICE – K.Shigaki

  12. Naïve Way: Direct Real Photons • measured as “excess” above hadron decay photon • Au+Au result consistent with pQCD×binary scaling • challenging at lower pT due to smaller S/B ratio PRL 94, 232301 (2005) Emerging Frontiers of Physics – High Energy Density QCD Frontier at ALICE – K.Shigaki

  13. Alternative: “Almost Real” Photons • low mass electron-positron pairs • p+p: hadronic decay + pQCD photon at high pT • Au+Au: enhancement above ~ 135 MeV • no p0 decay virtual photon above p0 mass PHENIX (A. Adareet al.), PRL 104, 132301 (2010) Emerging Frontiers of Physics – High Energy Density QCD Frontier at ALICE – K.Shigaki

  14. Direct Photon Spectra via g and g* • real and virtual photon methods consisitent • p+p data consistent with pQCD down to low pT • Au+Au above scaled pQCD at low pT • excess ~ exponential with 221  19  19 MeV PHENIX (A. Adareet al.), PRL 104, 132301 (2010) NLO pQCD (W. Vogelsang) Emerging Frontiers of Physics – High Energy Density QCD Frontier at ALICE – K.Shigaki

  15. Initial Temperature Evaluation • initial temperature > data slope ~ 220 MeV • 300–600 MeV from models • hydro-dynamical models describing data within factor of 2 • w/ t0 = 0.15–0.6 fm/c • cf. phase transition predicted at ~ 170 MeV slope transition temperature PHENIX (A. Adareet al.), PRC 81, 034911 (2010) Emerging Frontiers of Physics – High Energy Density QCD Frontier at ALICE – K.Shigaki

  16. Across the Boundary and Beyond • phase boundary: Tc ~ 170 MeV, ec ~ 1 GeV/fm3 “free gas” ? “perfect fluid” Emerging Frontiers of Physics – High Energy Density QCD Frontier at ALICE – K.Shigaki

  17. ALarge Ion Collider Experiment • the heavy ion experiment at LHC • 33 countries; 116 institutes; > 1,000 members • as of November, 2010 CMS LHCb ALICE ATLAS, LHCf Emerging Frontiers of Physics – High Energy Density QCD Frontier at ALICE – K.Shigaki

  18. ALICE Control Room on 23.11.2009 ~ 16:35 Emerging Frontiers of Physics – High Energy Density QCD Frontier at ALICE – K.Shigaki

  19. The First Event ~ 16:41 Emerging Frontiers of Physics – High Energy Density QCD Frontier at ALICE – K.Shigaki

  20. Collisions! Collisions!! Collisions!!! ~ 16:42 events reconstructed in hours Emerging Frontiers of Physics – High Energy Density QCD Frontier at ALICE – K.Shigaki

  21. First LHC Physics Paper, 28.11.2009 • charged particle density measurement • dNch/dh in p+p at 900 GeV • 3.10  0.13  0.22 (inel.) • 3.51  0.15  0.25 (NSD) ALICE Collaboration Eur.Phys.J.C65:111-125, 2010 National Geographic News (04.12.2009) ‘….a machine called ALICE.... found that a (!) proton-proton collision recorded on November 23 created the precise ratio of matter and antimatter particles predicted from theory..’ Emerging Frontiers of Physics – High Energy Density QCD Frontier at ALICE – K.Shigaki

  22. 7 TeV; The Highest Ever! • ALICE 2010 p+p data taking • > 800 M interactions • > 100 M muon triggers for J/Y • > 25 M high multiplicity triggers Emerging Frontiers of Physics – High Energy Density QCD Frontier at ALICE – K.Shigaki

  23. High Precision Measurements • wide pT coverage with particle identification • unique low pT reach at LHC Emerging Frontiers of Physics – High Energy Density QCD Frontier at ALICE – K.Shigaki

  24. Almost Zero Baryo-Chemical Potential • anti-proton/proton ratio in mid-rapidity region • 0.957  0.006 (stat)  0.014 (sys) at 900 GeV • 0.990  0.006 (stat)  0.014 (sys) at 7 TeV ALICE (K. Aamodtet al.), PRL 105, 072002 (2010) Emerging Frontiers of Physics – High Energy Density QCD Frontier at ALICE – K.Shigaki

  25. Vital Reference in New Energy Domain • e.g. closed/open heavy flavors • J/Y (c + c), D0, D, D (c + u/d (/s), u/d (/s) + c) J/Y m+m- J/Y e+e- Emerging Frontiers of Physics – High Energy Density QCD Frontier at ALICE – K.Shigaki

  26. Now, Long Awaited Pb+Pb Run • 2.76 TeV Pb+Pb from 07.11.2010–06.12.2010 • 14 times higher sNN than at RHIC Emerging Frontiers of Physics – High Energy Density QCD Frontier at ALICE – K.Shigaki

  27. ALICE 2010 Pb+Pb Data Taking • ~ 10 mb-1 delivered; > 90 M recorded in total • ~ 3 ×initial expectation Emerging Frontiers of Physics – High Energy Density QCD Frontier at ALICE – K.Shigaki

  28. Collision “Centrality” • tight correlation among several measures • scaling to “# participants” + “# binary collisions” • based on geometrical Glauber model • most peripheral collisions not separable from EM processes Emerging Frontiers of Physics – High Energy Density QCD Frontier at ALICE – K.Shigaki

  29. Multiplicity and Energy Density • dNch/dh = 1600  76 (sys) • high side of predictions • faster growth with s than in p+p • i.e. s dependent nuclear amplification • ~ 3 times higher energy density than at RHIC • lower limit; likely higher with shorter time scale ALICE (K. Aamodtet al.), PRL 105, 252301 (2010) back at RHIC Emerging Frontiers of Physics – High Energy Density QCD Frontier at ALICE – K.Shigaki

  30. Hotter, Bigger, Longer-Lived Fireball Enhancement p+p 7 TeV radius ~ 1/width Pb+Pb 2.76 TeV Pair Momentum Difference • particle interferometry • aka HBT or Bose Einstein correlations • quantum enhancement of identical bosons close in phase space • space-time evolution of co-moving volume • lifetime also accessible via Fourier transformation (E, p)  (t, x) • ~ 2 times bigger, 20–30% long-lived than at RHIC • ~ 300 fm3, ~ 10 fm/c ALICE (K. Aamodtet al.), PLB 696, 328 (2010) Emerging Frontiers of Physics – High Energy Density QCD Frontier at ALICE – K.Shigaki

  31. Jet Quenching and Mono-Jet Df Dh Dh Df • quark/gluon energy loss in partonic matter • first signature of hot and dense matter at RHIC • jet energy imbalance in single events • new at LHC! • full statistics analysis in progress • ALICE uniquely capable to include low pT particles high pT hadron quenched jet hadrons (jet) quark (anti-)quark hadrons (jet) high pT hadron Emerging Frontiers of Physics – High Energy Density QCD Frontier at ALICE – K.Shigaki

  32. Jet Quenching in Traditional View normalization including CDF data normalization by 0.9 TeV ×NLO (2.76 TeV) / NLO (0.9 TeV) • particle yields suppressed at high pT • quantified with “nuclear modification factor” • similar overall trend at LHC and RHIC • minimum value ~1.5 times smaller • rising with pT; newly clear at LHC • p+p reference limiting; 2.76 TeV p+p needed ALICE (K. Aamodtet al.), PLB 696, 30 (2011) LHC-ALICE charged particles RHIC-PHENIX p0 Emerging Frontiers of Physics – High Energy Density QCD Frontier at ALICE – K.Shigaki

  33. Heavy/Hard Probes at QCD Machine • ~ 10×charming and ~ 100×beautiful than at RHIC • powerful probes with known mass and color charge charm/beauty sNN (mb) shadowing multiplicity • p+p 14 TeV 11.2/0.5 1.0/1.0 0.16/0.007 • central Pb+Pb 6.6/0.2 0.65/0.85 115/4.6 • jets also even more powerful than at RHIC Emerging Frontiers of Physics – High Energy Density QCD Frontier at ALICE – K.Shigaki

  34. Closed Heavy Flavors in Pb+Pb • J/Y suppression as a signature of deconfinement • observed at RHIC and SPS; interpretation ambiguous • sequential melting?  further suppression at LHC • melting and regeneration competing?  enhancement at LHC •  another key to resolve mechanism • (partial) answer expected from 2010 data • ~ a few 103 J/Y in hand Emerging Frontiers of Physics – High Energy Density QCD Frontier at ALICE – K.Shigaki

  35. More Fun Stuffs, Too • e.g. anti-nuclei • … and even more exotics, e.g. anti-hyper-nuclei ~ 2 M minimum-bias Pb+Pb Emerging Frontiers of Physics – High Energy Density QCD Frontier at ALICE – K.Shigaki

  36. LHCRun History and Plan • LHC run history and schedule • 09.2008 first beam circulation • 11–12.2009p+p, s = 900 GeV, 2.36 TeV • 2010–2012 p+p at s = 7 TeV (and 2.76 TeV) Pb+Pb at sNN = 2.76 TeV • expectations in following few years • p+ps = 14 TeV, 1031 cm-2s-1 (ALICE), 107 s/y s = 5.5 TeV, 1031 cm-2s-1, 106 s/y×1 y • Pb+PbsNN = 5.5 TeV, 1027 cm-2s-1, 106 s/y • p+Pb sNN = 8.8 TeV, 1029 cm-2s-1, 106 s/y×1 y • Ar+Ar sNN = 6.3 TeV, 1029 cm-2s-1, 106 s/y×1 y Emerging Frontiers of Physics – High Energy Density QCD Frontier at ALICE – K.Shigaki

  37. Thermal Photon Hunting at ALICE • ALICE photon spectrometer: PHOS • photons,nuetral mesons, jet tagging • + L0, L1 trigger capability • wide coverage from 100 MeV to 100 GeV • high eneregy resolution, high granularity • s/E ~ 3 %/E up to 100 GeV • PbWO4 crystals of 22 (1.0 RMoliere)×22×180 (20 X0) mm3 • APD+ charge sensitive pre-amplifier readout • cooled and controlled at -250.1 C • |h| < 0.12, Df = 100 at 4.6 m • 56×64×5 modules; 17,920 channels, 12.5 t • 3 (/5) modules in operation hadron decays pQCD processes ~ pT-n compton scattering annihilation fragmentation thermal ~ e-E/T jet-medium interaction jet-photon conversion bremsstrahlung Emerging Frontiers of Physics – High Energy Density QCD Frontier at ALICE – K.Shigaki

  38. Early Physics Prospects via Photons • (very) high pT neutral meson suppression • high acceptance/statistics in early p+p and Pb+Pb • comparable to (or better than) years at RHIC • higher pT reach + stronger suppression at LHC • clearer measurement of quark energy loss • (less background for direct photon measurement) Emerging Frontiers of Physics – High Energy Density QCD Frontier at ALICE – K.Shigaki

  39. Toward Thermometer at LHC • prospect of thermal photon direct measurement • hotter, bigger, longer-lived fireball • reduced background due to quenching • ALICE-PHOSdetector • signal/background ~ 4–10 % (3 GeV/c) – 25–50 % (10 GeV/c) • systematic error ~ 8.9 % (2 GeV/c) – 5.7 % (10 GeV/c) • access to thermal properties of partonic system • Quark-Gluon Plasma factory • frontier expeditions on QCD phase diagram Emerging Frontiers of Physics – High Energy Density QCD Frontier at ALICE – K.Shigaki

  40. Summary and Concluding Remarks • boundary to partonic phase crossed at RHIC! • Tinit = 300–600 MeV “measured” • transition predicted at ~ 170 MeV by lattice QCD • LHC/ALICE now exploring new QCD frontier regime • 900 GeV, 2.36 TeV, 7 TeV p+p in 2009–2010 • 2.76 TeV Pb+Pb in 2010 • higher statistics p+p and Pb+Pb in 2011–2012 • expeditions hunting partonic phase properties • hard/heavy probes at “QCD machine” • “soft” photonic probes for comprehensive understanding • physics harvests blooming at LHC HI programs Emerging Frontiers of Physics – High Energy Density QCD Frontier at ALICE – K.Shigaki

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