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Heavy Quarks Measurements with a Forward Silicon Upgrade

Heavy Quarks Measurements with a Forward Silicon Upgrade. μ. Patrick L. McGaughey. April 29, 2005. Outline. Why Measure Heavy Quarks? Make quantitative measure of QGP properties PHENIX Silicon Vertex Endcap Detector Detector Design (4.6M$ cost) Simulations of Performance

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Heavy Quarks Measurements with a Forward Silicon Upgrade

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  1. Heavy Quarks Measurements with a Forward Silicon Upgrade μ Patrick L. McGaughey April 29, 2005

  2. Outline • Why Measure Heavy Quarks? • Make quantitative measure of QGP properties • PHENIX Silicon Vertex Endcap Detector • Detector Design (4.6M$ cost) • Simulations of Performance • Estimated Event Rates • Impacts on Muon Arm Performance • Summary

  3. Why Heavy Quarks ? • Have only qualitative evidence for QGP formation - can make • quantitativemeasurements with heavy quarks • Heavy quarks (charm and beauty) - produced early in the • collision. Live long enough to sample the plasma • Intrinsic large mass scaleallows precise calculations • Mass dependence of diffusion of heavy quarks determines • plasma properties, e.g. viscosity and conductivity • Yields of charm and beauty pairs compared to first principle • lattice simulations determine the energy density and • temperature • Comparison between light and heavy quark suppression • distinguishes between theoretical models of energy loss in the • QGP Heavy quarks can provide a unique determination of the properties of the plasma

  4. Heavy Quarks - Signals • Energy loss • Energy loss of heavy quarks in QGP is expected to be much larger than in normal nuclear matter, contrast with light quarks • Debeye screening • J/Y dissociates into DD in the QGP  measures temperature • Flow • Heavy quarks that thermalize in the QGP will show hydrodynamic flow • Total charm • In a QGP, increase from thermal production, strongly temperature dependent Currently large theoretical spread of "melting" temperatures of heavy quark bound states

  5. z y x Evidence for the Quark-Gluon Plasma – Hydrodynamic Flow Hydrodynamic pressure gradients drive system evolution – results in anisotropic particle emission Au Anisotropy: Au First time hydro limit with QGP equation-of- state is reached in heavy ion collisions! No Flow

  6. D (charm)  e + X Data from PHENIX Au+Au Large flow S/N < 1/1 No flow Charm and beauty inferred from electrons, but electrons come from many sources  Poor S/N! v2 from electron measurement Note large errors, electrons (and muons) are difficult, but provide heavy quark signal 20+% Systematic error on yield

  7. Evidence for Strongly Interacting Opaque Plasma Energetic quarks undergo large energy loss in the QGP Data – PHENIX (from cover of PRL!) Predictions – Vitev, LANL JRO Au Au d+Au RAA Absence of QGP effect Au+Au Strong suppression of pions from Au+Au versus p+p and d+Au collisions

  8. Measuring Plasma Characteristics Using Quark Energy Loss Light quark energy loss Ivan Vitev • State-of-the-art heavy • quark E-loss calculations To independently constrain and to and to incorporate non-equilibrium field theory transport coefficients into the evaluation of energy loss

  9. The PHENIX Detector Muon Arm Au Au J/ Muon Arm

  10. Silicon Vertex Detector Upgrade Pinpoint the decay vertex to eliminate backgrounds! Au   Au Endcaps detect following by displaced vertex (r, z) of muons: D (charm)  μ + X B (beauty) μ + X B  J/  + X  μ+ μ- Si planes constructed of strips 50 m by few mm long

  11. Design of SVD  x x x x • 4 Tracking stations composed of Si pixels, 50 um by few mm long • Electronics recently developed by FNAL, ~250,000 channels / pixels. • First low power, high speed and high resolution pixel detector • Can detect large numbers of B decays and D decays per year at RHIC

  12. Hytec, Inc. Conceptual Design of PHENIX Vertex Detector Upgrade April 1, 2005?

  13. Vertex Detector CAD Drawings

  14. Vertex Detector CAD Drawings

  15. Endcap Detector Components -Conceptual layout of the PHX pixel readout chip. PHX is derived from BTeV FPIX readout chip 512 channels/chip Bump or wire bonds Left panel : Green is bonding, blue the programming interface, red the discriminator, orange the pipeline and yellow the digital interface.Right panel : bonding layout, 200 micron pad spacing. Signal and power bus is routed on the surface on the chip.

  16. Endcap Detector Components –Conceptual Detectors mm Three silicon detectors sizes - largest has 6 chips with 3072 strips, intermediate has 5 chips with 2560 strips, smallest silicon has 3 chips and 1536 strips.

  17. Endcap Detector Assemblies Octagon panel structure with cooling channel. Heat load is 0.1 W/cm2. Detectors mount on front and back. Octagonal disk structures for the endcap ministrips. Cooling tubes shown to demonstrate number and routing.

  18. Endcap Detector Electronics Chain

  19. Fiber 2.5 Gbit/s OASE chip Slow Control ~100 Hz LVDS 6 x 160 MBit RISC onboard Hit: 9 bit address ,3 bit adc, 4 bit chip-id, tag 8bit, i.e.24 bits 1 % Occupancy translates into: 60 x 24-bits in <0.6 micro seconds ! 5 x 512 channels Overview of Asynchronous Panel Readout Simulations give 0.7% max Occupancy, 1st layer, in central Au-Au

  20. LINUX PCs PHENIX DAQ Emulator FPGA GLink Event Tag DATA (copy) Readout Unit (PCI bus) Fiber 2.5 Gbit/s OASE chip Slow Control ~100 Hz TRACKING FPGA DATA IN FPGA Arcnet Level I or II Trigger Output Overview of Receiver Board Physical interface – PCI cards in Linux farm

  21. Outer envelope : radius 20cm, length 80cm Silicon : inner radius 2.5cm, outer radius 14 cm Radiation length goal : 1% per disk Endcap Tracker Specifications

  22. Dramatic Signal / Background Improvement for Heavy Quarks with SVD After vertex cuts Before vertex cuts Muon Events charm Background charm Background beauty pT (GeV/c) pT (GeV/c) Simulated Signal to Noise for D +X without SVD and with SVD, 10 X improvement is signal / background  accurateyield, slope of charm

  23. Endcap performance - Vertex Resolution for Single Muons Charm: s=290 mm Beauty: s=230 mm Simulated endcap z-vertex resolution for D m+X and B m+X Z reconstructed B lifetime is ~ 1 mm at low pT()=1.7 GeV c (B+-) = 496 um, c (B0) = 464 um c(D+-) = 315 um, c(D0) = 124 um

  24. Simulation of B-> J/y -> m+m-with Endcap VTX 1mm cut Prompt J/y σ=133μm 1mm vertex cut eliminates >99.95% of prompt J/y Ratio of B decay to prompt J/y ~ 1% Events B decays p+p √S=200 GeV L=1036 RHIC 10*L0 ~400 B-> J/y per day Decay Distance (cm)

  25. Measurement of gluon shadowing and spin structure function with VTX Extracting gluon structure function • Vertex detector provides broad range in x in the predicted shadowing region (x <= 10-2) and at larger x • Measure gluon shadowing in p+A versus p+p, gluon spin in polarized p+p Gluon Shadowing Predictions coverage

  26. Correlation between Muon Momenta and Gluon x-Values for Charm Decays x2 x1 PZμ PTμ Similar correlation for Beauty decays

  27. PHENIX Decadal Plan

  28. PHENIX Run Plans from Beam Use Proposal Done Now 

  29. From Tony Frawley, for two full silicon endcaps.

  30. Other Benefits of VTX upgrade to PHENIX muon program , J/,’-VTX will improve mass resolution and background rejection. , ’, ’’ – VTX can improve detection of these at rapidities near zero. μ+ μ-Continuum - S/N can be greatly improved by VTX. Charm, beauty and Drell-Yan pairs can be separated. Possible detection of thermal charm pairs. e μpairs– VTX upgrade would improve S/N of these charm decays.

  31. Summary • Goal: • Detailed study of Heavy Quark production in p-p, p-A (d-A) and A-A collisions at RHIC. • Physics with VTX upgrade • Total charm and beauty cross sections, thermal charm • Energy loss and flow of charm and beauty in nuclear/quark matter • Nuclear dependence (gluon shadowing) of charm and beauty production over a wide x range • DG(x) measurement over wide x range (polarized protons) • Proposed Silicon vertex detector • 2 Si end caps (4 mini-strip layers each) • Proposal for central Si barrel sent to DOE (July 2004), proposal for endcap to follow in 2005.

  32. Backup slides

  33. From Tony Frawley, for two full silicon endcaps

  34. gconversion p0 gee h gee, 3p0 w ee, p0ee f ee, hee r ee h’  gee Cocktail Calculation • pT distribution of 0 are constrained with PHENIX 0 and  measurement • pT slope of , ’  and  are • estimated with mT scaling • pT = sqrt(pT2 + Mhad2 – M2) • Hadrons are relatively normalized by • 0 at high pT from the other • measurement at SPS, FNAL, ISR, RHIC • Material in acceptance are studied for • photon conversion • Signal above cocktail calculation can be seen at high pT

  35. e X D Au Au D J/ m B m X p K Direct Observation of Open Charm and Beauty Detection of displaced decay vertex will allow clean identification of charm and bottom decays • Detection options: • Beauty and low pT charm through displaced e and/or m • Beauty via displaced J/ • Charm through D   K Central arm & barrel VTX muon arm & endcap VTX Need secondary vertex resolution < 50 mm (barrel), < 150 mm (barrel)

  36. Silicon Vertex Upgrade μ B IP Endcaps detect following by displaced vertex of muons : D  μ+ X B  μ+ X B  J/ + X μ+ μ- Endcap mini-strips : 50 mm x few mm long ~1.0% X0 per layer Instrumented with BTeV ASICs Secondary vertex resolution ~133 mm

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