PDRC 2/4/03 #1 RHIC d-A and A-A Mike Leitch, P-25 PHENIX  Arms Parton structure, modification in nuclei and the Quark Gluon Plasma (QGP) PHENIX: Muon arms, Multiplicity & Vertex Detector (MVD) and Forward Calorimeter (FCal) –Performance & Commissioning LANL Contributions & Obligations MVD

PDRC 2/4/03 #2 RHIC/HENP Physics Program at LANL Parton structure, modification in nuclei, spin-dependence and the Quark Gluon Plasma (QGP): Flavor asymmetry of the nucleon sea and its spin-dependence (M. Liu) Polarized structure functions from polarized p-p collisions (M. Liu) Gluon structure functions and their shadowing in nuclei Energy loss of partons in nuclei. Contrast cold-nuclear matter (d-Au collisions) with hot/high-density matter (Au-Au collisions) Heavy-quark production and suppression: J/  suppression in d-Au collisions and in hot/dense matter Reaction plane and centrality dependence for d-Au and A-A collisions, e.g. how much nuclear matter does a pass through after it is created or what densities are achieved in a collision

PDRC 2/4/03 #3 Drell-Yan E866 R(W/Be) E772 R(W/D) Ratio(W/Be) Drell-Yan Process Modification of parton momentum distributions of nucleons embedded in nuclei, e.g. shadowing – depletion of low-momentum partons. Gluon Shadowing - Largely Unknown Gluon shadowing for J/Ψ -> μ + μ  in PHENIX? Eskola et al. hep-ph/ : ~ 0.8 Kopeliovich et al. hep-ph/ : ~ 0.4 Need to measure it in d-Au collisions x 2 is the momentum fraction of the target nucleon that a parton (quark or gluon) carries x F is fraction of maximum CM momentum, i.e. “how fast is it (e.g. a J/  ) going” X2X2 Eskola Kopeliovich d+Au -> J/  xFxF Anti-quark Shadowing

PDRC 2/4/03 #4 Kopeliovich et al hep-ph/ & hep-ph/ without Shadowing much weaker for open- charm production than for charmonium Anti-shadowing Whereas in the ordinary parton model shadowing “factorizes” and is a “property” of the nuclear structure function Process Dependence of Shadowing? with shadowing

PDRC 2/4/03 #5 Analysis of our p-A Drell-Yan data (E772 & E866) using the color-dipole model gives: dE/dz = ± 0.37 GeV/fm Johnson, Kopeliovich et al. PRL 86, 4483 (2001) Shadowing only dE/dx & Shadowing Quark energy loss in nuclear matter E772 Drell-Yan data x1x1 x1x1

PDRC 2/4/03 #6 Central Au-Au Scaled p-p pTpT E. Wang and X.N. Wang, hep-ph/ Anomolous Suppression of high-p T Hadrons peripheral central PHENIX Preliminary (Au-Au)/(p-p) Most significant result from RHIC so far, e.g. Wang -> 7.3 GeV/fm parton dE/dx d-Au baseline is critical for verification

PDRC 2/4/03 #7 Production: color singlet or octet ( ) and color neutralization timescale Hadronization time, i.e. distance before physical resonance formed Absorption on nucleons or on co-moving light quarks Feed-down from higher mass resonances, e.g. χ c Production of heavy vector mesons, e.g. J/Ψ, Ψ ',  and the QGP J/Ψ suppression – an effective signature of Quark-gluon plasma (QGP) formation? Color screening in a QGP would destroy pairs before they can hadronize into charmonium Began with prediction by Matsui and Satz (Phys. Lett. B178, 416 (1986)) that Debye color screening will lead to suppression of charmonium production in heavy ion collisions, if a quark-gluon plasma is formed. More recent predictions of increased J/  production at RHIC from recombination. But ordinary nuclear effects also absorb or modify J/Ψ’s Quark-gluon Plasma (QGP) deconfined quarks in a hot- dense region, a phase transition

PDRC 2/4/03 #8 Nuclear Dependence of Charm Production: E866/NuSea J/Ψ and Ψ’ similar at large x F where they both correspond to a traversing the nucleus But Ψ’ absorbed more strongly than J/Ψ near mid- rapidity (x F ~ 0) where the resonances are beginning to be hadronized in nucleus. open charm: no A-dep at mid-rapidity Hadronized J/  E866/NuSea: 800 GeV p-A (Fermilab) PRL 84, 3256 (2000) Phys. Rev. D52, 4251 (1995)

PDRC 2/4/03 #9 NA50 -- Anomalous J/  Suppression, Evidence for QGP?? Expected J/  yields are corrected for "ordinary" nuclear absorption assuming 6.4 mb absorption cross section J/  ->  decays measured / expected We need a comprehensive understanding of charmonium production in nuclei as a baseline for QGP studies PL B477, 28 (2000)

PDRC 2/4/03 #10 We can not discriminate between scenarios, given our present statistical accuracy 200A GeVAu-Au J/  ee Phys. Lett B 521 (2002) 195 All curves normalized to pp data point (bit of a hoax) QM02 – Run-II Au-Au Data (~10 J/  events)

PDRC 2/4/03 #11 Expected J/  ’s in present PHENIX d-Au (run-III) PHENIX has very broad coverage in x F, p T and x 2 by combining –North Arm –Central Arm –South Arm #J/  d-Au 10 wks p-p 3 wks South8.2k10.8k North7.5k9.9k Central2.1k2.8k from PHENIX Beam Use Proposal 8/16/02

PDRC 2/4/03 #12Magnet Muon Identifiers Muon 12.5° 35°35° 10.5° 2 Muon Trackers = 2x3 stations 2x3 stations 2 Muon Identifiers = 2x5 planes South Arm: Began operations in run. North Arm: Installed in 2002, now running. PHENIX Muon Arms Acceptance : 1.2 < |  | < 2.4,  Muon minimum momentum ~ 2 GeV/c Tracking Stations

PDRC 2/4/03 #13 South Muon Arm North Muon Arm Multiplicity & Vertex Det. (MVD)

PDRC 2/4/03 #14 North Chambers and Mechanics Tracking chambers – designed at LANL and built with collaborators Station 1 Quadrant at BNL Station 2 Octant at BNL Station 3 Octant at BNL Station 2 Support Structure

PDRC 2/4/03 #15 Front-End Electronics (FEE) Installation and Commissioning Copy of South arm FEE led and built by LANL, with minor changes With strong contribution from French for North arm including funding and manpower Electronics being assembled And installed

PDRC 2/4/03 #16 LANL North Arm FEE Contributions Mechanical support designed and overseen at LANL, built at NMSU Calibration system Optical Fiber Copper electronics system HV Distribution system designed and built at LANL Rack and cable layout completed at LANL Optical  Copper Translation System North Magnet Layout and FEE Support Structures Calibration System HV dist.

PDRC 2/4/03 #17 J/  from the 1st Year

PDRC 2/4/03 #18 Factor of ~1.8 more J/  ’s for p-p from tuning of pattern recognition software Better handling of skipped planes Corrections for swapped cables Better projections between stations Important for p-p (not just Au-Au) Realistic sigma’s for points in each plane Mixing with real events to determine efficiencies more reliably Resolved acceptance disagreements between simulations and data Mass resolution now agrees between simulations and data: ~180 MeV for J/  Tracking/pattern recognition progress led by LANL (We wrote the original code and have led all developments)  = 265 MeV  = 185 MeV Old Latest  Mass(GeV) Run-II p-p data

PDRC 2/4/03 #19 Sta-1 Sta-2 Sta-3 Radiographs of active area for South arm in run-II. (Three stations with 3 or 2 gaps each) Vast improvement for present (run-III) after extensive repairs to electronics and HV during shutdown 2003 Newly installed North Arm is working well Gap-1 Sta-1 Sta-2 Sta-3 Gap-2 Gap-3 Gap-1 Gap-2 Gap-3

PDRC 2/4/03 #20 Dimuon Event from Run-III

PDRC 2/4/03 #21 Pad detectors Beam goes through here Multiplicity and Vertex Detector (MVD) ~64 cm long barrel “1.5 layers” with ~25K Si strips ~6K Si pad detectors in endcaps covers -2.5 < y < 2.5 (9 <  < 181 deg) 1/4 MVD under construction: Readout electronics What is it? Brief history: Problems with Multi-chip module (MCM) yield & production schedule. Phenix year-1 ~30% instrumented Phenix year-2 ~60% instrumented Phenix year-3 completed

PDRC 2/4/03 #22 From the Review of the MVD at BNL, Oct. 29, 2002: “The MVD group has made good progress in dealing with the technical problems that have plagued them in the past two runs. Hardware problems have all been solved and a majority of electronics problems have been solved. Construction and installation are under control with adequate manpower.” “The physics case for the MVD is compelling in pp, dA, with no significant drawbacks. These include – giving a precision vertex for muon measurements, multiplicity measurements over a wide rapidity region, reaction plane measurements, and Dalitz rejection and track confirmation for pp measurements and centrality determination.”

PDRC 2/4/03 #23 Multiplicity & Vertex detector (MVD) dN/dη from MVD for 125 Au-Au simulated events PHENIX w/o MVD : | η | < 0.35 simulation Au-Au data from PHENIX run-III data (from MVD) dN ch /d  arbitrary units) Rapidity Precision vertex (~0.1 mm) Multiplicity (impact parameter) reaction plane fluctuations dN/d  for charged particles over very broad rapidity range

PDRC 2/4/03 #24 MVD vertex resolution & efficiency for p-p, p-Au & Au-Au collisions 2 cm or better vertex resolution needed by muon tracking to preserve J/  resolution of ~130 MeV; otherwise 200 MeV MVD-BBC vertex diff. ( cm): Good resol- ution Simulation Run-II Au-Au data

PDRC 2/4/03 #25 Reaction Plane In a heavy ion collision, the initial collision zone is “almond-shaped” High pressure in the excited region translates the initial spatial asymmetry into a measurable asymmetry in the final state. The asymmetry is ~5%, but there are ~5K particles. The MVD should be able to find this reaction plane to within degrees. This gives another interesting way to look at jet suppression and J/  suppression vs. the length of excited matter traversed. b = impact parameter (beam into page) shorter path longer path

PDRC 2/4/03 #26 The PHENIX forward-hadron calorimeter Tagging with grey protons Refurbished E864 calorimeters installed inside ring for PHENIX – Measuring forward protons from the fragmenting nucleus in d-A collisions provides a sensitive measure of N binary (# binary collisions) – Measurement of the undeflected proton from a deuteron in the d-A program can help differentiate between p-A like collisions and n-A like collisions. First result - correlation with the PHENIX beam-beam counter

PDRC 2/4/03 #27 LANL Contributions to PHENIX Defined much of the physics program for PHENIX muons and spin & major contributors to PHENIX CDR Led in getting the muon arms into PHENIX & conceived the spin program including bringing the Japanese (RIKEN) group into PHENIX. Physics-based design & construction of Muon spectrometers & MVD in PHENIX Continuing Contributions: Finish commissioning MVD & Muon Arms (2003) Planning for Run-III, e.g. triggering (Silvermyr) Run-III: d-Au ~ Jan. 1 (11 wks); p-p ~ Apr. 7 (3 wks) Shifts (~2 weeks/person), sub-system experts (MVD & MuTr) on call 24hrs/7 days, 7 periods as shift-leader so far, period coordinator(Leitch, 2 weeks as floor mgr.), … Luminosity targets are sufficient to get, e.g. ~ 15k (d-Au) J/  ’s Detector Council representatives for MVD (Sullivan) and Muon Tracking (Leitch); PHENIX Executive Council (Leitch) Software/Analysis lead for Muon tracking (Brooks, McGaughey, Liu) and MVD (Sullivan, vanHecke).

PDRC 2/4/03 #28 Physics Working Groups, particularily Heavy Quarks, Global and Spin. Convenor for hadron group (Sullivan, 2-yr term) Many paper writing committees, e.g. first J/  paper (Brooks), single- electrons (Leitch), long hadron paper (Burward-Hoy, van Hecke), 1 st PHENIX paper (Silvermyr), … Former high-p T convenor for STAR (Kunde) RHIC/AGS Users Executive Committee (Burward-Hoy) Maintenance with strong French contribution for muon electronics For MVD; lifetime limited by plans for silicon vertex detector (<= 2005?) Silicon vertex upgrade design & construction (LDRD seeded, R&D funding requested); focus on conceptual/engineering & design in next year (Lee, McGaughey). Many students have worked with us on this project LANL Contributions to PHENIX - II

PDRC 2/4/03 #29 People in RHIC/HENP Program Barnes, Brooks, Kunde, Lee, Leitch, Liu, McGaughey, Moss, Sullivan, VanHecke; Silvermyr(PD), Burward-Hoy(PD); and Sondheim, Boissevain (Engineers) Recently added two new high-level physics leaders (Liu, Kunde) and 1 postdoc. Plan to add at least one more postdoc. Issues & Concerns Finally emerging from construction & need to assure a strong leadership in physics. Relying on good people – e.g. new high-level staff and more postdocs are critical! Working towards more visability to the community & our sponsors in terms of physics leadership Advancing new physics-motivated construction projects while still maintaining a balance with strong leadership in physics