Process

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