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Process

This technical note discusses the process and requirements for a strawman detector to achieve more realistic physics simulations and goals in the field of physics. It includes information on spin, gluon structure function, open charm and beauty, energy loss of heavy quarks, and more.

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Process

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  1. Process Physics Goals Requirements, strawman detector Technical options More realistic simulations LOI, R&D $….. Technical note May 02 Craig Ogilvie

  2. Physics Goals • Spin, broad range in x of gluon spin structure function • 0.002 < x < 0.4 via open charm, beauty • Gluon structure function in A • Same channels and x-range as above • Information on early stage of HI collision • Open charm enhancement • More robust, and to higher pt, than existing capability • Open beauty • J/y / open charm • Energy-loss of heavy quarks • Upsilon…. Displaced vertices matched to central, muon arms Equal physics justificationfor each arm Craig Ogilvie

  3. Strawman Detector (Fall 2001) Established that a schematic detector could meet physics goals Each Si layer, 1% radiation length {detector, cooling, support} • Barrel r = 2.5, 6, 8, 10 cm, -1.2 < h < 1.2 * pixel barrels * strip barrels * pixel disks endcap, pixels 4 circular disks z=16, 23, 30, 37cm 1.2 < |h| < 2.4 End of this talk, plans to make this simulation more realistic Determine how large the endcaps need to be Craig Ogilvie

  4. Summary of Strawman Simulations, Technical Note May 2002 • Measure electron displaced vertex, rms < 40 mm • (Charm electrons)/(other electrons) at pt = 1 GeV/c • Improves from S/B ~1 to ~5 with a DCA cut of 125 mm • D => Kpp seems feasible • Measure muon displaced vertex, z rms ~ 100 mm • (Charm muons)/(other muons) • Improves from S/B < 1 to ~ 10 at pt ~ 3 GeV/c • Measure J/y displaced vertex, B => J/y • Muon channel simulated, z rms ~ 133 mm • Mean decay position z ~ 1mm • Vertex cut ~ 1mm removes several sigma of direct J/y • Rate, pp lum. 8*1031 , total 400 B per day into both arms Craig Ogilvie

  5. Technical Progress 1.5mm 1.5mm 80mm*1mm 700mm 300mm 1.5mm 2.7cm 2.4cm 3cm 2.785cm 6cm • Si Strip sensors • Sample ordered, test this summer/fall • Response, cross-talk,… 375 strips * 2 (x, stereo)* 2-ends = 1500 channels Craig Ogilvie

  6. Strip Readout Electronics • John Haggerty, survey of existing readout chips • SVX4, Fermilab, • 0.25mm CMOS final verison being tested this fall • pipeline 20-30 ms • ADC output, checking if physics benefits from this • ABCD/SCTA128-VG • DMILL process, low-yield, being phased out? • Long pipeline • Binary output / discrimnator • AP6 • Analog optical output • Hybrid pixel readout Craig Ogilvie

  7. Si Pixels • Hybrid • NA60/Alice • Johann, Hiroaki @ CERN working on prototypes • FPX2 from Fermilab • Should be evaluated • Both ~ 50 mW per pixel channel (110 W inner barrel) • Monolithic • Strasbourg design modified by Iowa State • Amp/adc at base/top of each column • Each pixel read twice to subtract correlated noise • Submission to MOSIS June 2002 Craig Ogilvie

  8. Next Steps for LOI • Simulations • End-cap, establish size to match muon acceptance • Joint effort with HBD/TPC • Move to semi-realistic masses, electronics, cooling • Simplified detector response • Does ADC help position resolution (centroid) ? • Track in B-field • Resolution improvements for upsilon • High-pt background rejection • Link to physics goals • x-range for structure functions • S/B, Rates, … Craig Ogilvie

  9. Next Steps for Technical and R&D Funding Proposal • Continue evaluation of strip readout options • R&D Funds FY03, FY04.. • Strips, • System tests with leading FEE candidate • Hybrid pixel, • Thinning, FEE tests • Monolithic pixel • Iteration of FEE with pipelining • Tests with thick epitaxial layer Craig Ogilvie

  10. Backups Craig Ogilvie

  11. Spin Structure Function of Proton GS95 ΔG（ｘ） prompt photon cc->eX bb->eX J/ x • Broad range of observables => low-x and large-x • Vertex detector adds p+p =>cc =>eX p+p =>bb =>emX 2 displaced vertices e, m b-tags Explores production mechanism for variety of channels, global fit, how much spin does the glue carry Craig Ogilvie

  12. pA Charm, Bottom Production prompt photon cc->eX bb->eX J/ • Reaction mechanism of heavy-flavor, e.g. initial state scattering • Towards extracting gluon structure function nuclei, shadowing • consistency of several observables • At very low-x, possibility of gluon saturation Vertex detector adds p+A =>cc =>eX p+A =>bb =>emX L. Frankfurt, M. Strikman Eur. Phys. J A5, 293 (99) Q = 2 GeV Q = 5 GeV Q = 10 GeV Craig Ogilvie

  13. Matching to Muon Arms • Match tracklets in Si to muon spectrometer • cut on same charge • momentum similar to 50% before/after muon shielding • match hit within 3s on first tracking layer m xhit-xproj (cm) Craig Ogilvie

  14. Central Arm: Electrons from D decay • Without cuts on displaced vertex • S/B ~ 1 for high-pt • S/B ~ 0.1 pt=0.5 GeV/c Craig Ogilvie

  15. Distance of Closest Approach e-track dca collision vertex 50mm x 425mm pixels, full multiple scattering dca resolution (electrons) < 50 mm less than ct, D0: 125mm D±: 317 mm Craig Ogilvie

  16. Signal/Background With DCA Cut • S/B from 2 to 10 => sample largely e from D-decay • large momentum range => spectra and yields of D Craig Ogilvie

  17. Hadronic Decays of D • Construct invariant mass => extract counts => spectra • multiple scattering, slow hadrons, makes this very tough • Provides 2nd measure of D spectra, consistency with D=>e+X D+ => K-p+ p+(BR 9%) full multiple-scattering three displaced tracks, parent points to collision Lc Craig Ogilvie

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