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Relativistic Heavy Ion Experiments at Yonsei

Relativistic Heavy Ion Experiments at Yonsei. Ju Hwan Kang (Yonsei University) the 4th Stanford-Yonsei Workshop (HEP session) February, 26, 2010. OUTLINE. Introduction De-confinement and Quark-Gluon Plasma (QGP) Relativistic Heavy Ion Collider (RHIC) at BNL Highlights of RHIC results

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Relativistic Heavy Ion Experiments at Yonsei

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  1. Relativistic Heavy Ion Experiments at Yonsei Ju Hwan Kang (Yonsei University) the 4th Stanford-Yonsei Workshop (HEP session)February, 26, 2010

  2. OUTLINE • Introduction De-confinement and Quark-Gluon Plasma (QGP) Relativistic Heavy Ion Collider (RHIC) at BNL • Highlights of RHIC results High PT suppression Thermal photon • Our activities PHENIX upgrade ALICE at LHC

  3. Deconfinement & RHIC Lattice Calculations: Tc = 170 ± 15% MeV (~2 x 1012 K) • QCD : established theory of the strong interaction • Quarks and gluons deconfined at high temperatures, at least from Lattice QCD • RHIC : Relativistic Heavy Ion Collider (√s = 200 GeV/nucleon) • To make a hot QCD matter by colliding heavy ions

  4. RHIC’s Experiments STAR

  5. High pT particle production At RHIC, most of high pT particles are fromjets. hadrons jet • proton-proton collision: • hard scattered partons • fragment intojets of hadrons hadrons • nucleus-nucleus collision : parton energy loss if partonic matter supprssion of high pThadrons no suppression of high pTphotons

  6. High pT suppression or jet quenching • Compare high pT distribution of p+p and Au+Au after scaling with the number of nucleon-nucleon binary collisions (Ncoll). • If the properties of the medium produced after the collision is the same for both cases, the two distributions should be identical. • The suprression of high pT particles in Au+Au compared to p+p would indicate the existence of a partonic matter. Ncoll can be calculated by looking at ET or multiplicity of produced particles 100% 0 %

  7. direct / 0 in p+p at s = 200 GeV direct 0 p+p at s = 200 GeV Run 2005:preliminary (Run 2003 data: PRL 98 (2007) 012002) Agreement with pQCD: Prerequisite for jet quenching calculations in A+A

  8. direct / 0 in Au+Au at s = 200 GeV Au+Au p0 + X (peripheral) Au+Au p0 + X (central) Strong suppression Au+Au direct + X Blue lines:Ncoll scaled pQCD p+p cross-section Peripheral spectra agree well with p+p (data & pQCD) scaled by Ncoll Data exhibits suppression: RAA=red/blue < 1

  9. Evidence for Parton Energy Loss? No energy loss for g‘s Energy loss for quark and gluon jets 0’s and ’s are suppressed, direct photons are not:Evidence for parton energy loss (jet quenching, indicating production of deconfined state or QGP)

  10. Thermal photons in nucleus-nucleus collisions g q g q Time Thermalizedmedium (QGP!?), T0 > Tc ,Tc 170 - 190 MeV( thermal ) Phase transitionQGP → hadron gas Freeze-out Initial hard parton-partonscatterings( hard )

  11. Thermal photons (theory prediction) g q g q p p r g Hadron decay photons S.Turbide et al PRC 69 014903 • High pT (pT>3 GeV/c) pQCD photon • Low pT (pT<1 GeV/c) photons from hadronic gas • Themal photons from QGP is the dominant source of direct photons for 1<pT<3 GeV/c • Measurement is difficult since the expected signal is only 1/10 of photons from hadron decays

  12. Virtual Photon Measurement 0 Dalitz decay Compton Any source of real g can emit g* with very low mass. Relation between the g* yield and real photon yield is known. Process dependent factor • Case of hadrons (p0, h) (Kroll-Wada) • S = 0 at Mee > Mhadron • Case of direct g* • IfpT2>>Mee2 S = 1 • For m>mp, p0 background (~80% of background) is removed • S/B is improved by a factor of five Direct g p0 h

  13. Extraction of the direct  signal r = direct g*/inclusive g* fdirect : direct photon shape with S = 1 • Interpret deviation from hadronic cocktail (, , , ’, ) as signal from virtual direct photons • Fit in 120-300MeV/c2(insensitive to p0 yield) arXiv:0804.4168 arXiv:0912.0244 A. Adare et al., PRL accepted

  14. Direct photon spectra exp + TAA scaled pp arXiv:0804.4168 arXiv:0912.0244 • Direct photon measurements • real (pT>4GeV) • virtual (1<pT<5GeV) • pQCD consistent with p+p down to pT=1GeV/c • Au+Au = “scaled p+p” + “expon”: Fit to pp NLO pQCD (W. Vogelsang) The inverse slope TAuAu > Tc ~ 170 MeV

  15. Press release WHEN: Monday, February 15, 2010, 9:30 a.m. WHERE: The American Physical Society (APS) meeting, Marriott Wardman Park Hotel, Washington, D.C., Press Room/Briefing Room, Park Tower 8222 DETAILS: The Relativistic Heavy Ion Collider (RHIC) is a 2.4-mile-circumference particle accelerator/collider that has been operating at Brookhaven Lab since 2000, delivering collisions of heavy ions, protons, and other particles to an international team of physicists investigating the basic structure and fundamental forces of matter. In 2005, RHIC physicists announced that the matter created in RHIC's most energetic collisions behaves like a nearly "perfect“ liquid in that it has extraordinarily low viscosity, or resistance to flow. Since then, the scientists have been taking a closer look at this remarkable form of matter, which last existed some 13 billion years ago, a mere fraction of a second after the Big Bang. At this press event, scientists will present new findings, including the first measurement of temperature very early in the collision events, and their implications for the nature of this early-universe matter.

  16. Our activities in PHEMIX • PHENIX upgrades and NCC • NCC is W-Si Sandwich calorimeter • NCC measures /0 to study /jet correlations • Our activities for NCC • Silicon pad sensor production • Micromodule production • Cosmic muon test • Beam test at CERN

  17. PHENIX & RHIC upgrade plans 40x design luminosity for Au-Au via electron cooling Commissioning Long term upgrades FVTX, TPC/GEM, NCC Long term: full detector and RHIC upgrades Near term: Base line Medium term: first upgrades 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 Analysis of data on tape Near term detector upgrades of PHENIX TOF-W, HBD, VTX , mTrig RHIC luminosity upgrade PHENIX upgrades Full utilization of RHIC opportunities: Studies of QGP with rare probes: jet tomography, open flavor, J/, ’, c, (1s), (2s), (3s) Complete spin physics program p-A physics RHIC baseline program Au-Au ~ 250 mb-1 at 200 GeV Species scan at 200 GeV Au-Au energy scan Polarized protons  150 nb-1 Extended program with 1st detector upgrades: Au-Au ~ 1.5 nb-1 at 200 GeV Polarized p at 500 GeV (start p-A program)

  18. NoseCone Calorimeter (NCC, or ForCal) • EM (W-Si) calorimeter in the forward rapidity • good -0 separation with reasonable energy resolution • Measurement of /jet correlations and high pT photon

  19. EM Shower in W-Si Sandwich calorimeter 15mm, RM 20cm,  20X0,  1λ

  20. Exercise for silicon pad sensor production

  21. Micromodule (Packaging)

  22. Cosmic test setup (sensor & electronics) Micromodule(Sensor) Preamp card 8Ch. fADC(100MHz) Bridge board

  23. Beam test at CERN • PS for below 6GeV, and SPS for up to 100GeV 7 vertical channels grouped (cost issue) 8 pad sensors in one carrier board Preamp hybrid

  24. Production and test results ~ 100 sample micro-module production has completed. Mechanical and electrical issues have been checked Total yield = 102/141 = 73% (most loss from sensor fabrication) Beam test results : & good linearity

  25. ALICE (A Large Ion Collider Experiment) at CERN LHC To study even hotter QCD matter...

  26. LHC SPS ALICE

  27. Our activities in ALICE • R&D for Forward EM calorimeter • To measure high pT photon in forward rapidity • Discussing a similar type of detector as NCC • Presented the results from our NCC efforts • TRD participation • TRD measures electrons and low pT photons • Participating in TRD integration and taking TRD shifts • Plan to analysis TRD data for photon physics

  28. TRD (Transition Radiation Detector) • |η|<0.9, 45°<θ<135° • 18 supermodules in Φ sector • 6 Radial layers • 5 z-longitudinal stack  total 540 chambers  750m² active area  28m³ of gas • In total 1.18 million read-out channels

  29. Student at CERN Participating in TRD integration

  30. FoCAL in AliROOT • PHENIX at RHIC PHENIX upgrade plans NCC Involvement • ALICE at LHC R&D for ForCal Participation in TRD

  31. Hosted ALICE upgrade workshop

  32. 1st Paper

  33. “Current” plan for LHC Please find below the outcome of a meeting to define the LHC running schedule for the next few years. We will have a long run spanning 2010 and most of 2011 at 7 TeV (presumably with a short technical stop again during Christmas 2010, but this has still to be decided), followed by a long shutdown starting mid to end 2011 to bring the machine up to its design Energy. A long run now is the right decision for the LHC and for the experiments. It gives the machine people the time necessary to prepare carefully for the work that’s needed before allowing 14 TeV, or 5.5 TeV/nucleon .

  34. Backups

  35. Input hadron spectra for cocktail Fitting with a modified Hagedorn function for pion, for all other mesons assume m_T scaling by replacing p_T by

  36. Virtual photon emission rate Real photon yield Turbide, Rapp, Gale PRC69,014903(2004)

  37. Initial temperature Tave(fit) = 221 MeV TC from Lattice QCD ~ 170 MeV From data: Tini > Tavg = 220 MeV From hydrodynamicalmodels: Tini = 300 to 600 MeV, t0 = 0.15 to 0.6 fm/c Lattice QCD predicts a phase transition to quark gluon plasma at Tc ~ 170 MeV

  38. Further discussions?

  39. Direct Photons in Au+Au Blue line: Ncoll scaled p+p cross-section Direct photon is measured as “excess” above hadron decay photons Measurement at low pT difficult since the yield of thermal photons is only 1/10 of that of hadron decay photons PRL 94, 232301 (2005) Au+Au data consistent with pQCD calculation scaled by Ncoll

  40. Motivation : Direct  production • Leading order diagram in perturbation theory • Direct  production in p+p •  One of the best known QCD process… Really? Hard photon : Higher order pQCD Soft photon : Initial/final radiation, Fragmentation function

  41. (Plastic fiber + Air) Transition radiation (TR) is produced if a highly relativistic (γ>900) particle traverses many boundaries between materials with different dielectric properties. Electrons can be identified using total deposited charge, and signal intensity as function of drift time.

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