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PHENIX Heavy Flavor Measurements in the RHIC II Era

PHENIX Heavy Flavor Measurements in the RHIC II Era. Vince Cianciolo RHIC II Heavy Flavor Workshop April 28, 2005. Outline. Why are we interested in heavy flavor? PHENIX upgrades RHIC II luminosity guidance Into an era of precision heavy-flavor measurements at RHIC….

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PHENIX Heavy Flavor Measurements in the RHIC II Era

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  1. PHENIX Heavy Flavor Measurements in the RHIC II Era Vince Cianciolo RHIC II Heavy Flavor Workshop April 28, 2005

  2. Outline • Why are we interested in heavy flavor? • PHENIX upgrades • RHIC II luminosity guidance • Into an era of precision heavy-flavor measurements at RHIC… PHENIX RHIC II Heavy Flavor Measurements

  3. q: fast color triplet Induced gluon radiation? g: fast color octet Q: slow color triplet Energy Loss? QQbar: slow color singlet/octet Dissociation? Virtual photon: colorless Controls Real photon: colorless Unknown Medium Generic Advantages of Hard Probes • Produced early • Sample medium • Scale w/ Nbinary(in the absence of medium effects) • pp reactions calibrate probes, allowing detection of medium effects, test pQCD PHENIX RHIC II Heavy Flavor Measurements

  4. What would we like to know that heavy flavor measurements can tell us about? • Initial gluon density, shadowing • Dominance of gluon fusion production mechanism • Gluon spin structure function • Interaction of slow heavy quarks in the medium • Less energy loss than light quarks? • Participation in flow? • Test for additional thermal production • Onium production mechanism, suppression pattern • Backgrounds for other interesting signals • Drell-Yan, thermal di-leptons PHENIX RHIC II Heavy Flavor Measurements

  5. What can we measure? • Open heavy flavor (HF) • y, pT dependence • Centrality dependence • Reaction plane dependence • Tagged HF jets • HF di-lepton correlations • J/ • y, pT dependence • Centrality dependence • Reaction plane dependence • J/ - hadron correlations • Polarization • ’, c and B contributions • Compare to ’,  • Everything should be studied vs. √s, collision species. PHENIX RHIC II Heavy Flavor Measurements

  6. What have we measured (or collected data for)? • Open heavy flavor (HF) • y, pT dependence e • Centrality dependence e • Reaction plane dependence e • Tagged HF jets No • HF di-lepton correlations No • J/ • y, pT dependence e • Reaction plane dependence No • J/ - hadron correlations No • Polarization No • ’, c and B contributions No • Compare to ’,  No • Everything should be studied vs. √s, collision species. e • e – Good start on exploratory measurements • c : 0.8 < pT (GeV/c) < 2.5 • c+b : pT (GeV/c)< 4.5 • Species : dAu, pp, CuCu, AuAu • √s : 200 GeV • Statistics : More is always better (allows reduction in statistical and systematic errors) PHENIX RHIC II Heavy Flavor Measurements

  7. Silicon Vertex Detector • Four barrel layers • Two ALICE pixel bus layers • Two strip-pixel layers • Four end-cap pixel layers • Displaced vertex (σ ~50 m) • Full azimuthal inner tracking |η| < ~2.4 • Improve acceptance for -jet correlations, D  K • Connect to tracks in central and muon arms • Tag heavy flavor decays • c,b  e, • B  J/ • Improve onium resolution • Eliminate decay hadrons • Reduce high-pT background PHENIX RHIC II Heavy Flavor Measurements

  8. Nose Cone Calorimeter • Replace central arm magnet nosecones (Cu) w/ tungsten-silicon calorimeters • Coverage at forward/backward rapidity: 0.9 < |η| < 3.5 • /0 separation for pT < 30 GeV/c • Jet identification •  identification gives good acceptance for c  J/ +  PHENIX RHIC II Heavy Flavor Measurements

  9. Muon Trigger Upgrade • Three layers of RPCs with 2D (θ,φ) pad readout • Provides online momentum measurement to improve Level-1 trigger rejection • Single-particle • pT cut • W spin-measurements in pp • Two-particle • Minv cut • onium measurements in AA • Necessary to take complete advantage of luminosity upgrades • Provides improved high-multiplicity background rejection PHENIX RHIC II Heavy Flavor Measurements

  10. Be wary of Hypothetical Future Value predictions… As always, the Devil is in the details. Disclaimer When rate estimates look too good to be true they probably are. PHENIX RHIC II Heavy Flavor Measurements

  11. x 35 increase for pp x 10 increase for CuCu x 15 increase for dAu x 15 increase for AuAu RHIC II Luminosity – CAD Guidance http://rhicii-heavy.bnl.gov/doc/RHIC_II_Luminosity_Roser.xls PHENIX RHIC II Heavy Flavor Measurements

  12. RHIC II Yields – ADF, MJL Guidance • Assume CAD “Maximum Average” Luminosity Projection, 12 week runs, known PHENIX uptime (60%) to get Live Delivered Luminosity. • Use measured values when possible to calculate ppσ’s, B.R.’s. • Assume nuclear scaling - (AB), w/=1 for , =0.92 for others. • Use stated RF efficiency, diamond size to get vertex cut efficiency. • Use measured PHENIX performance, assume PHENIX SiVTX, Nosecone Calorimeter, Muon Trigger upgrades to get acceptances, efficiencies. PHENIX RHIC II Heavy Flavor Measurements

  13. Onium Yields • Precision measurements of the J/ • Exploratory measurements of the other onium states. • Steep increase at √s = 500 GeV illustrates the significant difficulties for measurements at lower energies. PHENIX RHIC II Heavy Flavor Measurements

  14. Other Yields • From similar estimates in SiVTX proposal: • D  K : 1000 counts (S/B ~ 3%) for central AuAu pT> 2 GeV/c • cc  e or  : pT< 7 GeV/c • bb  e or  : pT< 8 GeV/c • From CDR estimates scaled by onium yield expectations then and now • cc , cc  ee, cc  e : Minv < 8 GeV/c PHENIX RHIC II Heavy Flavor Measurements

  15. K- p+ Measuring Open Heavy Flavor in PHENIX • Measurement of open heavy flavor in PHENIX is based on the semi-leptonic decay modes of B and D mesons. • Other contributions to inclusive lepton spectra are determined and subtracted; remainder attributed to heavy flavor decays. PHENIX RHIC II Heavy Flavor Measurements

  16. Measuring Heavy Flavor (y=0) in PHENIX Cocktail Method • Many sources contribute to inclusive electron spectrum. • Dominant contribution from 0’s (via Dalitz decay and  conversion). • These are very well measured by PHENIX in the same apparatus. • S/B decreases w/ increasing pT. Inclusive electron spectrum in AuAu @ 200 GeV/c PHENIX RHIC II Heavy Flavor Measurements

  17. Measuring Heavy Flavor (y=0) in PHENIX Converter Method • At low-pT we directly measure dominant -conversion backgrounds by inserting an extra converter of known thickness. • Dalitz contribution follows deterministically. • Statistics-limited at high-pT (rely on cocktail, OK since S/B higher). Non-/ electron ratio For pT > 0.8 GeV/c S/B > 0.4 PHENIX RHIC II Heavy Flavor Measurements

  18. Note: Bottom dominates for pT> 2.5 GeV/c pp Results PHENIX data • Comparison with PYTHIA (tuned to available data) • pT < 1.5 GeV/c: reasonable • pT > 1.5 GeV/c: spectra “harder” than PYTHIA LO • hard fragmentation? • bottom enhancement? • higher order contributions? consistent with STAR (PRL 94, 062301 (2005)) within errors! • Comparison with FONLL • Fixed Order Next-to-Leading Log pQCD calculation (M. Cacciari, P. Nason, R. Vogt hep-ph/0502203) • better description of spectral shape • still room for further contributions • from jet fragmentation? PHENIX RHIC II Heavy Flavor Measurements

  19. Total Charm Yield  Nbinary • Background-subtracted “heavy-flavor” e± pT spectra vs. centrality w/ converter analysis • Insufficient statistics at pT > 1.5 GeV/c to study modification of spectral shape PHENIX: PRL 94, 082301 (2005) • Total charm yield in AuAu agrees with binary scaled pp yield (as expected for point-like pQCD process)! Total yield for pT > 0.8 GeV/c PHENIX RHIC II Heavy Flavor Measurements

  20. Charm May Flow • PHENIX HF electron spectra @ 130 GeV/c are compatible w/ no interactions and also with hydrodynamics. • Measure flow, go to higher pT S.S. Adler et al., nucl-ex/0502009 Theoretical predictions from Greco et al., Phys. Lett. B595, 202 Batsouli et al., Phys. Lett. B557, 26 PHENIX RHIC II Heavy Flavor Measurements

  21. PHENIX Preliminary RAA with yield above 2.5 GeV/c Charm RAA(pT) 1 • Need to go to cocktail analysis to obtain sufficient statistics at high-pT. • Will lower systematics at low-pT by combining with converter method. PHENIX RHIC II Heavy Flavor Measurements

  22. I hadron Idecay muon Iprompt muon Reconstructed to gap4 I3inclusive Total flux log I (particle flux) I3exclusive absorber Final Decay Muon flux Hadron punch-through Gap 0 1 2 3 4 Z (cm) 120 0 40 Measuring Heavy Flavor at Forward Rapidity in the PHENIX Muon Arms PHENIX RHIC II Heavy Flavor Measurements

  23. Decay muons Punch-through hadrons Prompt muons Measuring Heavy Flavor at Forward Rapidity in the PHENIX Muon Arms • Extract decay component from z-vertex slope of normalized muon yield. • Calculate punchthrough component with simplified absorption model: • Cocktail input not well-measured as in central-arm measurement. • Absorber thick, any error in strong interaction description amplified by ~e10. • At low (high)-pT systematics dominated by decays (punchthroughs, competing c/b production) PHENIX PRELIMINARY PHENIX RHIC II Heavy Flavor Measurements

  24. Detector upgrades assist by determining decay vertex. Allows direct measurement of charm via D  K Reduces backgrounds at low-pT Allows statistical separation of c/b at high-pT Allows direct elimination of hadron decay muons. Luminosity upgrades extend pT reach and allow reduction of systematic errors. Additional special runs (e.g., w/ different converter thicknesses and locations, different field configurations, etc.) Finer binning of DCA dependence for c/b separation. Better determination of punchthrough absorption. Expected D Kstatistical significance (S/√B) for different DCA cuts (pT > 2 GeV/c, 200M AuAu min. bias. events) Synergistic Benefits of Detector/Luminosity Upgrades for Open Heavy Flavor Measurement PHENIX RHIC II Heavy Flavor Measurements

  25. J/ in pp In pp we’ve measured the J/ close to pT = 0 and over much of the rapidity range. PHENIX RHIC II Heavy Flavor Measurements

  26. J/ in dAu Modest cold nuclear effects seen, but data are not sufficient to completely understand those effects. dA/ pp = (2A) PHENIX RHIC II Heavy Flavor Measurements

  27. Dy = 1.0 Coalescence model (Thews et al) Phys.Rev.C69, 014901,2004 Dy = 4.0 Stat. Model (Andronic et al.) Absorption model (Grandchamp et al.) J/ in AuAu • Low-statistics measurement in central arm from Run-2. • Much larger data sets in central and muon arms from Run-4 are currently in production. PHENIX RHIC II Heavy Flavor Measurements

  28. central arm north muon arm J/ in CuCu • We’re just getting started, but we have nice mass peaks from near-line analysis of LVL2-filtered data. PHENIX RHIC II Heavy Flavor Measurements

  29. Minv() – Minv() =1.0-1.5 Synergistic Benefits of Detector/Luminosity Upgrades for Onium Measurements • Statistics, statistics, statistics • Higher pT coverage • More centrality bins • More systems, energies • Triggering improvements needed for Level-1 di-muon triggering in ion collisions w/ RHIC II luminosity • Polarization • ′ and  • Background elimination • J/   background dominated by hadron decays which can be largely eliminated w/ silicon detector. • Resolution • Especially important for ′ and ’s • Feeddown • c  J/ +  (NC Calorimeter) • B  J/ + X (Forward Silicon) PHENIX RHIC II Heavy Flavor Measurements

  30. R. Rapp, nucl-th/0204003 Other HF Topics • cc  e+e- • Drell-Yan • IM di-leptons • Gluon structure function • Charm-jet tomography • Tag charm jet w/ electrons • Measure J/ near- and far-side correlations PHENIX RHIC II Heavy Flavor Measurements

  31. Fan? Wall? Spear? Rope? Tree? Snake? Conclusions • There’s a famous Indian fable about six blind men who come to very different conclusions about the form of an elephant due to their limited examinations. • With detector upgrades and RHIC II luminosities we can truly embark on precision heavy flavor measurements of sQGP (or whatever we choose to call the stuff we’ve made) and come to a better understanding of its full nature. • …Moral: • So oft in theologic wars, • The disputants, I ween, • Rail on in utter ignorance • Of what each other mean, • And prate about an Elephant • Not one of them has seen! • John Godfrey Saxe (1816-1887) PHENIX RHIC II Heavy Flavor Measurements

  32. Backup slides PHENIX RHIC II Heavy Flavor Measurements

  33. Silicon Vertex Detector – Details 2D single-sided detectors for outer barrels Vital stats Modified BTeV chip for end cap readout ALICE pixel bus for inner barrels PHENIX RHIC II Heavy Flavor Measurements

  34. Silicon Vertex Detector - Coverage • Complete coverage of central arms • Nearly complete coverage of muon arms • Two small regions w/ only two hit Si planes • Essentially 4 tracking for |η| < ~2.4 PHENIX RHIC II Heavy Flavor Measurements

  35. e/m compartments Hadronic (leakage) downstream 0/ identifier (strip-pixels) tungsten Single layer of stripPixels Nosecone Calorimeter – DetailsNot This Talk upstream Si pads PHENIX RHIC II Heavy Flavor Measurements

  36. scintillator RPC HV Muon Trigger Upgrade – Details Raw signals Time resolution ~ 3.5 ns Efficiency for cosmics PHENIX RHIC II Heavy Flavor Measurements

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