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The PHENIX Potential in the Search for the QCD Critical Point

Workshop on the Critical Point and the Onset of Deconfinement – 7/4/06 Jeffery T. Mitchell for the PHENIX Collaboration (Brookhaven National Laboratory). The PHENIX Potential in the Search for the QCD Critical Point . Outline PHENIX Detector and Performance

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The PHENIX Potential in the Search for the QCD Critical Point

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  1. Workshop on the Critical Point and the Onset of Deconfinement – 7/4/06 Jeffery T. Mitchell for the PHENIX Collaboration (Brookhaven National Laboratory) The PHENIX Potential in the Search for the QCD Critical Point • Outline • PHENIX Detector and Performance • Demonstrating Capabilities with Current Measurements • Contribution of Upgrades Jeffery T. Mitchell - Workshop on the Critical Point and Onset of Deconfinement – Florence, Italy – 7/4/06

  2. The PHENIX Detector 2006 • Charged Particle Tracking: • Drift Chamber • Pad Chamber • Time Expansion Chamber/TRD • Cathode Strip Chambers (Mu Tracking) • Particle ID: • Time of Flight • Ring Imaging Cerenkov Counter • TEC/TRD • Muon ID (PDT’s) • Calorimetry: • Pb Scintillator • Pb Glass • Event Characterization: • Beam-Beam Counter • Zero Degree Calorimeter • Shower Max Detector • Forward Calorimeter Jeffery T. Mitchell - Workshop on the Critical Point and Onset of Deconfinement – Florence, Italy – 7/4/06

  3. Current PHENIX Datasets p+p d+Au Au+Au Cu+Cu 22.4 GeV 62.4 GeV 130 GeV 200 GeV Run 1 - 3 Run 4 - 5 Run 6 CuCu 200GeV 1.08 Billion Events 157TB on tape CuCu 62.4GeV 630 Million Events 42TB on tape CuCu 22GeV 48 Million Events 3TB on tape p-p 200GeV 6.8 Billion Events 286TB on tape ------------------------------ 488 TB on tape for Run 5 Advances in data logging and the implementation of “multi-event buffering” increased our Event rate dramatically in Runs 4 and 5 Jeffery T. Mitchell - Workshop on the Critical Point and Onset of Deconfinement – Florence, Italy – 7/4/06

  4. RHIC low-E Feasibility • No apparent show-stoppers for RHIC collisions at Ecm = 5-50 GeV/n • Only equal energies • Unequal species possible only if minimum rigidity > 200 T-m • Without cooling long vertex distribution • Small set of specific energies (and species?) should be a workshop deliverable for planning: • 2.5,3.2,3.8,4.4… GeV/n total beam energy • Studies that should be done soon: • A ~1 day study period at low total beam energy to identify power supply, lifetime, tuning issues/limitations • Low-current superconducting magnet measurements • Pre-cooling in AGS  10x luminosity ? • Electron beam cooling would make this a fantastic facility: ~100x luminosity, small vertex distribution, long stores. RHIC Heavy Ion Collisions Expected whole vertex minbias event rate [Hz] T. Roser, T. Satogata Jeffery T. Mitchell - Workshop on the Critical Point and Onset of Deconfinement – Florence, Italy – 7/4/06

  5. Initial Machine Projections T. Roser, T. Satogata • Assumes expected luminosity scaling as 3 below 9.8 GeV/u • b*/aperture and integrated luminosity tradeoffs must be studied • Projections do not include potential improvements • Electron and stochastic cooling (peak and integrated luminosity) • Lattice modifications to mitigate IBS (integrated luminosity) • Total bunch intensity from vacuum improvements (peak luminosity) Jeffery T. Mitchell - Workshop on the Critical Point and Onset of Deconfinement – Florence, Italy – 7/4/06

  6. Participant To ZDC b ToBBC Spectator 15-20% 10-15% 5-10% peripheral central 0-5% 0-5% Centrality Determination: 62, 200 GeV 200 GeV Multiplicity distribution 62 GeV Jeffery T. Mitchell - Workshop on the Critical Point and Onset of Deconfinement – Florence, Italy – 7/4/06

  7. Centrality Determination: <25 GeV • At low beam energy, the BBC acceptance can cover spectator nucleons, affecting the linearity of the response. • For 22.5 GeV Cu+Cu, pad chamber 1 is used for the centrality determination. • Only 4 centrality bins (0-10%, 10-30%, 30-60%, and 60-88% are defined. • Using PC1 can introduce autocorrelations into some measurements. • A new centrality detector would be very useful for PHENIX at low energies. Jeffery T. Mitchell - Workshop on the Critical Point and Onset of Deconfinement – Florence, Italy – 7/4/06

  8. Measurement: ET, Multiplicity PHENIX preliminary PHENIX preliminary • “Classical” Shape: Peak, Valley, Edge. • Top centrality classes are shown individually. BEHOLD THE LOW ENERGY PHENIX DATA… Jeffery T. Mitchell - Workshop on the Critical Point and Onset of Deconfinement – Florence, Italy – 7/4/06

  9. Measurement: ET, Multiplicity 62.4 GeV PHENIX Preliminary PHENIX preliminary PHENIX preliminary • Consistent behavior for ET and Nch • Both increase with energy • Both show a steady rise from peripheral to central collisions Jeffery T. Mitchell - Workshop on the Critical Point and Onset of Deconfinement – Florence, Italy – 7/4/06

  10. Measurement: <ET>/<Nch> • The ratio <ET>/<Nch> increases by ~20% from 19.6 GeV to 200 GeV and stays the same between 200 GeV and 130 GeV • Consistent with the average particle momentum increase between those two energies. • The ratio <ET>/<Nch> is independent of centrality • Since trigger and centrality related uncertainties cancel out, the flatness of the curves is precise. PHENIX preliminary Jeffery T. Mitchell - Workshop on the Critical Point and Onset of Deconfinement – Florence, Italy – 7/4/06

  11. √sNN dependence • Both ET and Nch show log-scaling. • Works even better on Nch for Np = 350. [The band on the right is a 2σ error] • Extrapolation to LHC dNch/dη = (6.1±0.13)×(0.5Np). Jeffery T. Mitchell - Workshop on the Critical Point and Onset of Deconfinement – Florence, Italy – 7/4/06

  12. Measurement: Charged Hadron Yields Jeffery T. Mitchell - Workshop on the Critical Point and Onset of Deconfinement – Florence, Italy – 7/4/06

  13. Measurement: Charged Hadron Spectra Blast wave Jeffery T. Mitchell - Workshop on the Critical Point and Onset of Deconfinement – Florence, Italy – 7/4/06

  14. Charged hadron identification in PHENIX PHENIX EmCal (PbSc) Time of Flight - /K separation ~ 3 GeV/c - K/p separation ~ 5 GeV/c Electromagnetic Calorimeter - /K separation ~ 1 GeV/c - K/p separation ~ 2 GeV/c Jeffery T. Mitchell - Workshop on the Critical Point and Onset of Deconfinement – Florence, Italy – 7/4/06

  15. Measurement: pT spectra for pions Filled symbols : + Open symbols : - Jeffery T. Mitchell - Workshop on the Critical Point and Onset of Deconfinement – Florence, Italy – 7/4/06

  16. Measurement: pT spectra for kaons Filled symbols : K+ Open symbols : K- Jeffery T. Mitchell - Workshop on the Critical Point and Onset of Deconfinement – Florence, Italy – 7/4/06

  17. Measurement: pT spectra for protons * No weak decay feed-down correction applied Jeffery T. Mitchell - Workshop on the Critical Point and Onset of Deconfinement – Florence, Italy – 7/4/06

  18. Measurement: pT spectra for antiprotons * No weak decay feed-down correction applied Jeffery T. Mitchell - Workshop on the Critical Point and Onset of Deconfinement – Florence, Italy – 7/4/06

  19. Measurement: -/+, K-/K+ vs. pT Jeffery T. Mitchell - Workshop on the Critical Point and Onset of Deconfinement – Florence, Italy – 7/4/06

  20. Measurement: p/ Ratios • p/+ ratio :increasing as a function of sNN. • p/- ratio : decreasing as a function sNN. • Cu+Cu 22.5 GeV central data reaches the p+p values. Jeffery T. Mitchell - Workshop on the Critical Point and Onset of Deconfinement – Florence, Italy – 7/4/06

  21. Measurement: pbar/p ratio vs. pT Jeffery T. Mitchell - Workshop on the Critical Point and Onset of Deconfinement – Florence, Italy – 7/4/06

  22. Measurement: RAA for pions • p+p reference: global fit of pion data at s ~23 GeV (D. d’Enterria). • Error notations: • - Error bars: statistical error for Cu+Cu spectra • - Gray boxes: • 1) sys. error for p+p reference. • 2) sys. error for Cu+Cu spectra. • - Lines: Ncoll error (1.) • p+p reference: global fit of pion data at s ~62 GeV. • nucl-ex/ nucl-ex/0411049, D. d’Enterria. Jeffery T. Mitchell - Workshop on the Critical Point and Onset of Deconfinement – Florence, Italy – 7/4/06

  23. Measurement: RAA for kaons Jeffery T. Mitchell - Workshop on the Critical Point and Onset of Deconfinement – Florence, Italy – 7/4/06

  24. Measurement: p,p RAA Jeffery T. Mitchell - Workshop on the Critical Point and Onset of Deconfinement – Florence, Italy – 7/4/06

  25. Measurement: p0 pT Spectra New Run4 Data Cu+Cu 200 GeV 2.2 B sampled • Au+Au 200 GeV • Luminosity 241b-1 (sampled) • 1.5B events New Run5 Data Jeffery T. Mitchell - Workshop on the Critical Point and Onset of Deconfinement – Florence, Italy – 7/4/06

  26. Measurement: p0 pT Spectra • Go near SPS Energies • p+p data at 21.7 – 23 GeV • Use of parameterization as reference • 3 days of RHIC Run5 • 6.8M Events after quality cuts • Centrality via PC1 multiplicity p0 Jeffery T. Mitchell - Workshop on the Critical Point and Onset of Deconfinement – Florence, Italy – 7/4/06

  27. Measurement: p0 RAA Similar Npart (WA98 : 132, PHENIX: 140) same behaviour Jeffery T. Mitchell - Workshop on the Critical Point and Onset of Deconfinement – Florence, Italy – 7/4/06

  28. Cu+Cu @ 22.4 GeV consistent with SPS (Note: different system size) Measurement: p0 RAA nucl-ex/0504001 Jeffery T. Mitchell - Workshop on the Critical Point and Onset of Deconfinement – Florence, Italy – 7/4/06

  29. Measurement: v2 200 GeV Au+Au See Roy Lacey’s talk PHENIX preliminary • Transverse kinetic energy scaling works for a large selection of particles • Supports the idea that all particles originate from a common flow field Jeffery T. Mitchell - Workshop on the Critical Point and Onset of Deconfinement – Florence, Italy – 7/4/06

  30. Measurement: v2 200 GeV Au+Au See Roy Lacey’s talk • Scaling holds over the whole range of KET • KET/n gives kinetic energy per quark, assuming that each quark carries equal fraction of kinetic energy of hadron PHENIX preliminary Observation of scaling of v2 with quark kinetic energy could be used as input for recombination models Jeffery T. Mitchell - Workshop on the Critical Point and Onset of Deconfinement – Florence, Italy – 7/4/06

  31. Critical Exponent analysis of centrality-dependent fluctuations • Let’s assume that the increased fluctuations are indicative of critical behavior. Then, it is expected that a) the system can be described by critical exponents, and b) all systems can be described by the same set of critical exponents. In the Grand Canonical Ensemble: • The critical exponent for compressibility is represented by the symbol g and is described by • Replacing and solving for 1/kNBD gives (A=constant, T=Temperature, V=volume) Jeffery T. Mitchell - Workshop on the Critical Point and Onset of Deconfinement – Florence, Italy – 7/4/06

  32. Measurement: Multiplicity Fluctuations  Critical Exponents? 0.2 < pT < 3.0 GeV/c Comparison to NA49 measurements at SPS energies. All scaled variance data have been corrected for impact parameter fluctuations from their 5% and 10% wide centrality bins and scaled to lie on the 200 GeV Au+Au curve. The fits use g=1.2 (p=1/3); or g=1.1 (p=0). The typical value is 1.2-1.3. The NA49 data amazingly exhibit the same universal behavior! PHENIX Preliminary Jeffery T. Mitchell - Workshop on the Critical Point and Onset of Deconfinement – Florence, Italy – 7/4/06

  33. Measurement: <pT> Fluctuations S. Adler et al., Phys. Rev. Lett. 93 (2004) 092301. 0.2 < pT < pTmax Highlights: Non-random fluctuations are observed. Non-monotonic centrality-dependence. Strong pT-dependence. pT fluctuations appear to be driven by high pT particles. The shape can be explained using a PYTHIA-based simulation estimating the relative contribution of correlations due to jets. However, simulations show that the sensitivity to temperature fluctuations is strongly multiplicity-dependent. PHENIX sensitivity takes a large hit at low beam energies. Jeffery T. Mitchell - Workshop on the Critical Point and Onset of Deconfinement – Florence, Italy – 7/4/06

  34. The Upgraded PHENIX Detector Run-3: Design Configuration! FCAL • Charged Particle Tracking: • Drift Chamber • Pad Chamber • Time Expansion Chamber/TRD • Cathode Strip Chambers(Mu Tracking) • Forward Muon Trigger Detector Si Vertex Tracking Detector- Barrel (Pixel + Strips) • Si Vertex Endcap (mini-strips) • Particle ID: • Time of Flight • Ring Imaging Cerenkov Counter • TEC/TRD • Muon ID (PDT’s) • Aerogel Cerenkov Counter • Multi-Gap Resistive Plate Chamber ToF • Hadron Blind Detector • Calorimetry: • Pb Scintillator • Pb Glass • Nose Cone Calorimeter • Muon Piston Calorimeter • Event Characterization: • Beam-Beam Counter • Zero Degree Calorimeter/Shower Max Detector • Forward Calorimeter • Reaction Plane Detector • Data Acquisition: • DAQ Upgrade • Detector Redundancy • Fine Granularity, Mass Resolution • High Data Rate • Good Particle ID • Limited Acceptance • High rate trigger • Precision vertex tracking • Charged Particle Tracking: • Drift Chamber • Pad Chamber • Time Expansion Chamber/TRD • Cathode Strip Chambers(Mu Tracking) • Particle ID: • Time of Flight • Ring Imaging Cerenkov Counter • TEC/TRD • Muon ID (PDT’s) • Aerogel Cerenkov Counter • Calorimetry: • Pb Scintillator • Pb Glass • Event Characterization: • Multiplicity Vertex Detector (Si Strip,Pad) • Beam-Beam Counter • Zero Degree Calorimeter/Shower Max Detector • Forward Calorimeter PID (k,,p) to 10 GeV Rejection of Dalitz/Conv. / coverage to very fwd FCAL SMD/ Jeffery T. Mitchell - Workshop on the Critical Point and Onset of Deconfinement – Florence, Italy – 7/4/06

  35. Extended PID: AGEL + TOF-W n=1.018 +2 GeV/c • “An aerogel and time-of-flight system to provide complete p/K/p separation for momenta up to ~10 GeV/c.” • Project well underway • Aerogel completely installed (first physics results now available) • TOF-W (‘Time-Of-Flight-West’) • Partial funding: J. Velkovska (Vanderbilt) OJI • Prototypes tested in Run-5 • System to be installed in next shutdown Jeffery T. Mitchell - Workshop on the Critical Point and Onset of Deconfinement – Florence, Italy – 7/4/06

  36. RxNP resolution BBC RP resolution 0% 25% 50% 75% 100% Reaction Plane Det (RxNP) • Scintillator paddles with lead converter at 1<||<3 • Measure reaction plane • resolution better by factor 2 • Trigger counter for low energy running, where  is reduced from beam energy Jeffery T. Mitchell - Workshop on the Critical Point and Onset of Deconfinement – Florence, Italy – 7/4/06

  37. Hadron-Blind Detector (HBD) partner positron needed for rejection  e+ e - po   e+ e - “combinatorial pairs” total background S/B ~ 1/500 Irreducible charm bkg all signal charm signal • “A hadron-blind detector to detect electrons from near the vertex.” • Dalitz rejection via opening angle • Identify electrons in field free region • Veto electrons with partner • HBD: a novel detector concept: • windowless CF4 Cherenkov detector • 50 cm radiator length • CsI reflective photocathode • Triple GEM with pad readout • reverse bias  hadron blind • 2x135 in  and || < 0.45 • Construction 2005-2006, Installation in 2006 (4-6 weeks from now) • Funding provided by DOE, NSF, Weizmann, Stony Brook • R&D completed Cherenkov blobs e- e+ qpair opening angle Jeffery T. Mitchell - Workshop on the Critical Point and Onset of Deconfinement – Florence, Italy – 7/4/06

  38. Silicon Tracker • “A vertex detector to detect displaced vertices from the decay of mesons containing charm or bottom quarks.” • ~$3M committed by RIKEN • MIE proposal submitted to DOE Aug-04: • DOE Cost & Schedule review May, 2006 • Total Project Cost = $4.6M • In President’s Budget for FY07 • Very active ongoing R&D program • |h|<1.2 • ~ 2p z~ ± 10 cm Hybrid Pixel Detectors (50 mm x 425 mm) at R ~ 2.5 & 5 cm Strip Detectors (80 mm x 3 cm) at R ~ 10 & 14 cm Jeffery T. Mitchell - Workshop on the Critical Point and Onset of Deconfinement – Florence, Italy – 7/4/06

  39. Nosecone Calorimeter (NCC) • “A forward calorimeter to provide photon+jet studies over a wide kinematic range.” • Forward physics with PHENIX • Large acceptance calorimeter • EM calorimeter ~42 X/Xo • hadronic section (1.6 l/l0) • Tungsten with Silicon readout • Extended physics reach with NCC • Extended A-A program • high pT phenomena: p0 and g-jet • χc→ J/ + g(deconfinement) • Small x-physics in p(d)-A • Polarized proton physics • G(x) via g-jet • Status • Submitted to DOE for FY08 funding start • New expert groups join R&D (Moscow State, Czech groups) • Construction FY08 – FY10 0.9 < h < 3.0 10 XAcceptance of Central Arms Constraint W-silicon sampling calorimeter • -space • 40 cm from collision vertex • 20 cm total depth Densest highest spatial resolution 20 cm Jeffery T. Mitchell - Workshop on the Critical Point and Onset of Deconfinement – Florence, Italy – 7/4/06

  40. NCC NCC HBD MPC MPC VTX & FVTX Future PHENIX Acceptance for Hard Probes EMCAL 0 f coverage 2p EMCAL -3 -2 -1 0 1 2 3 rapidity (i) p0 and direct g with combination of all electromagnetic calorimeters (ii) heavy flavor with precision vertex tracking with silicon detectors combine (i)&(ii) for jet tomography with g-jet (iii) low mass dilepton measurements with HBD + PHENIX central arms Jeffery T. Mitchell - Workshop on the Critical Point and Onset of Deconfinement – Florence, Italy – 7/4/06

  41. Upgrade Schedule Scenario R&D Phase Construction Phase Ready for Data Jeffery T. Mitchell - Workshop on the Critical Point and Onset of Deconfinement – Florence, Italy – 7/4/06

  42. Conclusions • RHIC is capable of performing a low energy scan. • PHENIX is capable of producing high quality measurements now and in the future on the wide variety of observables that could be needed to isolate the QCD critical point. • PHENIX would benefit from a centrality detector designed specifically for low energy running. • However, to do cover all the bases, it would be nice to complete the program with: • Enough energy steps with sufficient statistics to map out any inflections about the critical point. • More than one species in order to investigate universal behavior and critical exponents near the critical point. • Companion p+p and d+Au data at each energy in order to reduce any systematic errors in measuring baseline distributions – important for RAA measurements. • Estimated time for a 3s correlation function measurement: 18 days at 20 GeV Jeffery T. Mitchell - Workshop on the Critical Point and Onset of Deconfinement – Florence, Italy – 7/4/06

  43. a Jeffery T. Mitchell - Workshop on the Critical Point and Onset of Deconfinement – Florence, Italy – 7/4/06

  44. Thanks to those who contributed directly to this presentation… • Martin Purschke • Alexander Milov • Tatsuya Chujo • Peter Steinberg • Christian Klein-Bosing • Christoph Baumann • Henner Buesching • Hiroshi Masui • Michael Issah • Todd Satogata • Mickey Chiu • … and many more Jeffery T. Mitchell - Workshop on the Critical Point and Onset of Deconfinement – Florence, Italy – 7/4/06

  45. Happy Independence Day (USA) Photos from Round 1: Italy 1, USA 1 Good luck to Italy AND Germany tonight in the World Cup Semi! Jeffery T. Mitchell - Workshop on the Critical Point and Onset of Deconfinement – Florence, Italy – 7/4/06

  46. Auxiliary Slides Jeffery T. Mitchell - Workshop on the Critical Point and Onset of Deconfinement – Florence, Italy – 7/4/06

  47. PHENIX Static Backup Slide • Pad Chamber Detectors: • MWPC with binary pad readout • 2.5m and 5.0m from the IP • |η|< 0.35 Δφ = 900 • σφ= 1.4mrad (3.5mm PC1) • ση= 0.7×10-3 (1.7mm PC1) • Double Hit Resolution ~4cm • Electromagnetic Calorimeter: • Lead+Scintillator 18 X0 • 5.1m from the IP • |η|< 0.38 Δφ = 900 • σE= 8.1%/√E[GeV] ×2.1% • Beam-Beam Counters: • 64 Cherenkov Counters • 3.1<|η|< 3.9 Δφ = 3600 • σvertex= ~5mm (central) • σt= ~100 ps Jeffery T. Mitchell - Workshop on the Critical Point and Onset of Deconfinement – Florence, Italy – 7/4/06

  48. Recalculation between systems. Illustration only • In C.M.S.: • At Mid-Rapidity: ET~mT • dET/dy ≈ 1.25 dET/dη • In Lab: • dmT/dy ≈ 1.25 dET/dy • dET/dy ≈ dET/dη • In C.M.S.: • dNch/dy ≈ 1.25 dNch/dη • In Lab: • dNch/dy ≈ 1.04 dNch/dη • Recalculation parameters are “rather” independent on energy • A systematic error of 5% is assigned to any recalculated value Jeffery T. Mitchell - Workshop on the Critical Point and Onset of Deconfinement – Florence, Italy – 7/4/06

  49. Comparison to other SPS results. • Good agreement between PHENIX measurements at 19.6 GeV and SPS measurements at 17.2 GeV in both measured values. • SPS spread of the data is larger than RHIC, but the same averaging should be possible to reduce the systematic errors. Jeffery T. Mitchell - Workshop on the Critical Point and Onset of Deconfinement – Florence, Italy – 7/4/06

  50. Measurement: Multiplicity Fluctuations  Critical Exponents? 0.2 < pT < 3.0 GeV/c Comparison to NA49 measurements at SPS energies. The NA49 scaled variance data have been corrected for impact parameter fluctuations from their 10% wide centrality bins and scaled up by 20% to lie on the 200 GeV Au+Au curve. The fits use g=-1.2, p=1/3; or g=-1.1, p=0. The NA49 data amazingly exhibit the same universal behavior! PHENIX Preliminary Jeffery T. Mitchell - Workshop on the Critical Point and Onset of Deconfinement – Florence, Italy – 7/4/06

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