PHENIX Upgrade and Nosecone Calorimeter

1. PHENIX Upgrade and Nosecone Calorimeter Ju Hwan Kang Yonsei University The 1st Asian Triangle Heavy Ion Conference (ATHIC 2006)Yonsei University, Seoul, Republic of KoreaJune 29, 2006 ~ July 1, 2006

2. The PHENIX Detector designed to measure rare probes:+ high rate capability & granularity + good mass resolution and particle ID - limited acceptance Au-Au & p-p (spin) • 2 central arms: ||<0.38 at y=0,  =  electrons, photons, hadrons • charmonium J/, ’ -> e+e- • vector mesonr, w,  -> e+e- • high pTpionπo ->γγ • open charm, beauty (D,Be) • direct photons • hadron physics • 2 muon arms: 1.2<||< 2.4,  = 2 muons • “onium” J/, ’,  -> m+m- • open charm, beauty (D,Bm)

3. Leading hadrons π0 γ π0 dAu AuAu Probing Partonic State of Matter The matter is so opaque that even a 20 GeV p0and charm is stopped. The matter is strongly coupled

4. requires highest AA luminosity Physics for PHENIX Upgrades The capability of the following physics can be enhanced by detector upgrades • High T QCD (AA, pA, and pp): • Electromagnetic radiation (e+e- pair continuum) • Heavy flavor (c- and b-production) • Jet tomography (high pT PID, jet-jet and g-jet) • Quarkonium(J/, ’ , c and (1s),(2s),(3s)) • Spin structure of the nucleon: • Gluon spin structure DG/G (heavy flavor and g-jet correlations) • Quark spin structure Dq/q (W-production for flavor decomposition) • Low x phenomena • gluon saturation in nuclei (particle production at forward rapidity)

5. barrel VTX |h| < 1.2 NCC 0.9 < h < 3.0 PHENIX Upgrades Project Precision vertex: VTX: Si tracker FVTX: forward Si e/π0 at forward y: NCC: nose cone calorimeter Dalitz, γ-conversion rejection: HBD: hadron blind detector High rate trigger: Muon trigger Provides displaced vertex & jet measurement over 2p endcap VTX 1.2 < h < 2.7 HBD FVTX VTX NCC MuonTrig MuonTrig

6. PHENIX Upgrades Physics Capabilities X upgrade critical for success O upgrade significantly enhancements program PHENIX upgrades designed for optimum physics output with RHIC II luminosity

7. HBD VTX & FVTX Future PHENIX Acceptance for Hard Probes NCC NCC EMCAL 0 f coverage 2p EMCAL MPC MPC -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 measurments with HBD + PHENIX central arms

8. PHENIX Upgrades Schedule R&D Phase Construction Phase Ready for Data

9. Two most recent PHENIX Upgrades (vertex displacement, track trajectory at forward rapidity) FVTX VTX (p0, photon measurements in Muon arm acceptance) NCC FVTX(~$4.5M) and NCC(~$4M) proposed to DOE, reviewed (March-2006) by external committee which recommended funding from FY08

10. p, K decays How FVTX Can Help • Significant reduction of backgrounds by accurately measuring the Distance of Closest Approach (DCA). Decay muon, punch-through hadron, and open heavy flavor decay muons can be separated on a track-by-track basis • Significant improvement in angular resolution of track leading to improvement in dimuon resolutions Prompt backgrounds cτ(D)=312µm cτ(K, π)=3.7m, 7.8m

11. EM1 electromagnetic EM2 electromagnetic HAD hadron identifier How NCC separate e/h p EM1/ETot e+ p EM2/ETot e+ Had/ETot

12. Leading hadrons π0 γ With FVTX Without FVTX What is the Physics I?With the vertex tracking & π0/γ at forward rapidity • Heavy Ion collisions (sQGP) • Getting a picture of collision system • Energy density of coll. sys. changes with rapidity  large rapidity coverage • Calibrated probe: γ-jet to get parton dE/dx (Eγ≈Ejet )large γ-jetacceptance • Understanding deconfinement, Tc • Testing J/ψ recombination, J/ψ melting at T>Tc from recent lattice: • better mass resolution, lower backgrounds, & separation of ’ • χcγJ/ψ: smaller BE, melts at lower T than J/ψ (~30% of J/ψ:χc decay feed-down) • measure both states to disentangle various effects • must go to forward rapidity to haveγ & J/ψ in muon arm acceptance

13. xG(x) x low x high x What is the Physics II? With the vertex tracking & π0/γ at forward rapidity • Proton Nucleus collisions (Colored Glass Condensate) • Gluon Saturation or Shadowing in Cold Nuclear Matter • Gluon Saturation, Color Glass Condensate (CGC) – large density of small-x gluons resulting in depletion at small-x • More saturation at lower x : y~log(1/x) since Measurement at lower x  cover the forward rapidity • Production (p+p vs. p+A) of high energy single hadrons (πo->γγ, φ->e+e-, …) at lower x to measure the amount of depletion • Kinematic variable of gluons can be readily reconstructed with γ-jet measurement: most of high pTγ’s are from “compton”  well determined xg measure gluon saturation via direct photons in forward region depletion at small-x

14. What is the Physics III?With the vertex tracking & π0/γ at forward rapidity Spin Puzzle from polarized DIS • polarized pp collisions (What makes up the nucleon spin?) • Precise measurement of the polarized gluon distribution, Δg(x)=g+(x)-g-(x), at RHIC to get the gluon spin contribution ΔG using double-spin asymmetry ALL • ΔG may be dominated by contributions from low-x where gluons are most abundant: y~log(1/x); e.g. x2=(e-y)2~10-3 for y=3, assumingx1=1 • Detection of both hadron jet and the photon with NCC: Jet + direct γ;givesconstraint on xg • ΔG with NCC at low-x through jet-γ, π0, J/Ψ, open charm NCC greatly expands reach of PHENIX in low x ΔΣ～20-30% σ++ σ+-

15. RHIC with Polarized Protons • Collisions of Longitudinally Polarized Protons • Gluon spin contribution (G) directly accessible • Direct photon is theoretically cleanest for gluon spin contribution • Use W± reaction to determine virtual sea contribution : not directly accessible in polarized DIS since gluon does not couple directly to photon and photon couples to q & q-bar in the same way

16. ΔG and Direct photons • Difficulties with π0 extraction of ΔG • Several diagrams contribute • fragmentation functions • ΔG using direct photons • ~90% of high pTγ’s are from compton • easier to find xg in this case

17. Detection of π0 in NCC (Nosecone Calorimeter) SM Total E: Calorimeter Position: PS Energy Asymmetry: SM π0 mass 500 um pitch Strips (“StriPixels”) PS “pre-shower” 2X0position SM “shower max” 7X0asymmetry 30 GeV π0 HAD hadron identifier Silicon pads 1.5x1.5 cm2 Tungsten 3 mm (EM) & 15mm (HAD) The PS and SM Detectors: identifyingπ0s Depth: 42X0 (1.6λABS)

18. p0 tracking: 5 GeV/c example p0 → gg, d = 25 mm Multitrack configuration tracks pointing to collision vertex (points in PS, EM1, SM, EM2, Had)

19. p0 tracking: 30 GeV/c example D(gg) ~ 4 mm single track configuration

20. ShowerMax PreShower

21. Fit to extract decay asymmetry Constrained to match gg separation measured in PS g1 g2 X-strip number Energy per strip [GeV] Y-strip number

22. π0 detection efficiency from simulation Single-particle (p0and e) simulation in NCC p0 efficiency

23. NCC: Schedule, Cost, and Groups • Scope of proposal to DOE: • 1st NCC ~ $4M • Recommend start of funding FY 2008 • Complete construction in 2010 • Groups working on NCC: BNL, Charles Univ, Columbia U, Czech Tech U, EWU-Korea, Inst Phys Czech Acad Sci, ISU, JINR-Dubna, Korea U, Moscow State, Myongji U, RIKEN, Stony Brook U, Tsukuba U, UCR, UIUC, Yonsei U • Four Korean groups and a company (SENS) are responsible for: • Fabrication and testing of prototype stripixel sensors • Production of entire stripixel sensors • Also partially responsible for the production of pad sensors, most of which may be produced in Russia and Czech

24. Production of stripixel sensors • Wafer will be ordered next week • First fabrication will be tried in the middle of July • Prototype fabrication of NCC stripixel sensors by ‘SENS’ company collaborating with YSU, EWHA, and KU • Two runs are foreseen by October • Sensors will be tested by Korean groups • More production in December for beam test • interleaved stripixel detector (ISD). • each pixel is divided into two parts: X-cell and Y-cell . X-strips and Y-strips connect X-cells and Y-cells, respectively. • Sensor: 62x62mm • Strip in pixel: width=10um, gap=14.7um • Readout strip pitch: 440um

25. Backup Slides

27. 60K pixels

28. Matching MuTr and Silicon tracks in Central AuAu (I) • Average 0.7% occupancy in highest occupancy areas (1.5% max. occ. tobe safe) • In Central AuAu events, ~ 3 silicon tracks match each MuTr track: use a Kalman-Filter fit to MuTr+Silicon hits and choose best χ2 • Pick track with best c2: 93%, 83%, 75% of the time the correct match is made for total momentum 9 GeV, 6 GeV, 3 GeV particles Hits/cm2 per Central AuAu event

29. NCC Silicon Stripixel Detector • The Si stripixel detector, developed at BNL (Brookhaven National Laboratory), • has been applied in the development of NCCdetector system for the • PHENIX Upgrade at RHIC. • The Si stripixel detector can generate X-Y two-dimensional(2D) position sensitivity • with single-sided processing and readout.