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First physics results with the Silicon Vertex Trigger at CDF-II

First physics results with the Silicon Vertex Trigger at CDF-II. 2 nd Workshop on the CKM Unitarity triangle. April 5 th -9 th IPPP Durham, England, UK Ivan Vila Instituto de Fisica de Cantabria. Outline . SVT motivation and overview. SVT performance. Charm and B physics with the SVT:

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First physics results with the Silicon Vertex Trigger at CDF-II

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  1. First physics results with the Silicon Vertex Trigger at CDF-II 2nd Workshop on the CKM Unitarity triangle. April 5th-9th IPPP Durham, England, UK Ivan Vila Instituto de Fisica de Cantabria

  2. Outline • SVT motivation and overview. • SVT performance. • Charm and B physics with the SVT: • Hadronic triggers • Semileptonic triggers • Summary Related CDF talks: Review on B lifetimes and lifetime differences J. Rademacker Bs mixing results and prospects at CDF/D0 D. Lucchesi Performance of CDF for B Physics R. Oldeman I. Vila 2nd CKM Workshop Durham

  3. B physics at Tevatron • Large b production cross-section • s(bb) ~ 100mb (10kHz @ E32) • s(B+, |y|<1, PT>6) ~ 3mb (300Hz @ E32) • compare: s(bb) ~ 1nb at U(4S) (5Hz @ 5E33) • Many B hadrons states produced: • B0, B+, Bs, Lb, Bc, b • But… HUGE inelastic cross section ~ 100mb A dedicated trigger needed I. Vila 2nd CKM Workshop Durham

  4. A new tool for selecting B’s Only available for Run I • CDF has three dedicated triggers for B/Charm physics • Dimuon • J/ygmm • Lepton + track • Semileptonic decays • Two track • Hadronic decays Implemented by the Silicon Vertex Trigger ~ 1 mm b, c decays primary vertex Silicon microstrip detector included in trigger ! secondary vertex impact parameter I. Vila 2nd CKM Workshop Durham

  5. Trigger Overview SVX II COT Tracks 0, Pt hits XFT hits SVT d0, 0, Pt s(1/PT)=1.0%/GeV s(f)=1.5mrad s(d)=35um d0 Beam axis • Bunch crossing: 396 ns: 2.5 MHz • Level 1: fast programmable logic • Synchronous 5.5 ms latency • Calorimeter, Muon, Tracks • Accept rate 15kHz (reduc. ~x200) • SVT trigger paths ~ 40% bandwidth • Level 2: programmable logic + CPU • Asynchronous ~ 20 ms latency • Cal cluster, Silicon track • Accept 300 Hz (reduction ~x50) • SVT trigger paths ~ 17 % bandwidth • Level 3: Linux PC farm • ~ Offline quantities • 50 Hz (reduction ~ x6) • SVT trigger paths ~ 25% bandwidth I. Vila 2nd CKM Workshop Durham

  6. SVT: key techniques • How do we do silicon track reconstruction in about 15 microseconds? • (1) Do everything you can in parallel and in a pipeline. • (2) Pattern recognition: • Database with all patterns corresponding to good tracks • Compare in parallel hits in each event with previous patterns to find track candidates • Bin coordinate information coarsely into roads. • This is done in a custom VLSI chip (Associative Memory). • (3) Linearize the fitting problem. • i.e. solvable with matrix arithmetic I. Vila 2nd CKM Workshop Durham

  7. SVT:Pattern Recognition Single Hit XFT info road 1 road z Road road y 4 Detector Layers Superstrip The AM chip is the physical realization of the template matching pattern recognition algorithm: each AM Chip can compare each hit with all the patterns in memory in parallel, providing the high speed necessary for trigger applications. With the AM, pattern recognition is complete as soon as the last hit of an event is read! Like in a bingo game. Coarser resolution 250 m superstrips 95% coverage each 30o slice: 2AM boardx128chipsx128roads~32.000 roads I. Vila 2nd CKM Workshop Durham

  8. SVT Performance: precise and fast 24 ms Level 1 accept to SVT done 9 ms before the first hit is received + ~ 15 ms processing time • IP resolution ~ 50 mm • Includes 33 mm beam spot • Beam position is computed at real time and subtracted online I. Vila 2nd CKM Workshop Durham

  9. SVT Performance:Efficiency • Efficiency evaluated on a sample of J/   Efficiency can still be improved by requiring 4 hits out of the five SVX layers, so far 4 out of 4 I. Vila 2nd CKM Workshop Durham

  10. SVT Performance:Online monitor. Using tracks found at L3 calculate Kinvariant mass Excellent online trigger Monitor: The number of D0 per luminosity unit has to remain constant if detector and trigger are performing well. I. Vila 2nd CKM Workshop Durham

  11. The Two Track Trigger • 2Tracks with: PT>2. GeV, SVT 1 mm > IP >120mm & PT1+PT2 >5.5 GeV • Collect ~70 pb-1 of Data ~ 0.5M D0gKp signal • Will have O( 107 ) fully reconstructed decays in 2 fb-1 data set !! • Competive, compare FOCUS today’s standard for huge: 139K D0K-p+, 110K D+K-p+p+ • Charm production cross section measured and compatible SM I. Vila 2nd CKM Workshop Durham

  12. The Two Track Trigger (2) with D* tag W/o D* tag • Very high purity D0 signal using “D* tag” technique • D*+gD0p • M(D*)–M(D0): • s(MD) ~ 10 MeV • s(DM) ~ 0.6 MeV • 20% of the D0 : D*+ tagged • Eliminate the “reflection” background (D0gKp and pK) • Initial flavor of D0 is known • D*+g D0 + p+ / D*-g D0 + p- • The best place to study D0 mixing and CP violation I. Vila 2nd CKM Workshop Durham

  13. The Two Track Trigger (and 3) + Magnetic field correction + Energy loss correction (dE/dx in the tracking detector) Before correction • Ds, D+gfp ; fgKK • 10 pb-1 of two track trigger • Measure mass difference • 99 ± 0.38 ± 0.21 MeV/c2 • PDG: 99.2±0.5 MeV (CLEO2, E691) • Momentum scale of the tracking detector is calibrated using the J/ygmm • Then extensively tested using Ksgpp, D0gKp, Ugmm, … First Run II paper ! DM I. Vila 2nd CKM Workshop Durham

  14. Lepton + Track Trigger • Lepton + Track : 1 m/e pT> 4 GeV +1 other track with pT > 2 GeV, SVT 1mm >IP > 120 mm and M(l-Track) < 5 GeV • Collect ~60 pb-1 of data ~ 0.5M B g lX signal • Lepton + Track dataset (60 pb-1) • BglD0X (D0gKp) : ~ 10K • BglD*+X (D*gD0p): ~ 1.5K • BglD+X (D+gKpp): ~ 5K • Good signals for calibration • Measure B+ and B0 lifetime • Study B0-B0 mixing I. Vila 2nd CKM Workshop Durham

  15. Lepton + Track Trigger (2) • Bsgln DsX (Dsgfp) • LbglnLcX (LcgpKp) Lifetime studies ~ 0.12 ps (PDG:0.08 ps) Future: semileptonic form factor Lifetime studies ~ 0.07 ps (PDG:0.057 ps) Future: Bs mixing (low Dms case) I. Vila 2nd CKM Workshop Durham

  16. Summary • The Silicon Vertex Trigged significant step forward in the quality of fast track finding in hadron collider physics. • A massively parallel/pipelined architecture was used combined with innovative techniques: the associative memory and linearized track fitting • A world plenty of Charm: • Used as benchmark for B two body charmless decays. • The large statistics CDF as world class charm factory. • B fully hadronic and semileptonic decays are under reconstruction • First physics measurements using SVT based samples. • Getting ready for the large luminosity: Bs mixing, Lb and Bs lifetimes, sin 2b… I. Vila 2nd CKM Workshop Durham

  17. Back up slices • JUST IN CASE… I. Vila 2nd CKM Workshop Durham

  18. CDF II Forward Muon Muon system Central Calorimeters Solenoid Old Partially New New Plug Calorimeter Time of Flight Drift Chamber Silicon Microstrips Tracker I. Vila 2nd CKM Workshop Durham

  19. Tevatron D0 CDF Tevatron Lpeak: ~1x1032s-1cm-2 Bunch spacing: 396 ns p source Main Injector & Recycler I. Vila 2nd CKM Workshop Durham

  20. Integrated Luminosity Good Run Silicon is off (beam condition) Mar 02 Jan 03 Data used for Today’s results Mar 02 – Jan 03 130 pb-1 (delivered) 100 pb-1 (to tape) Jet physics: ~ 85 pb-1 B/Charm: ~ 70 pb-1 commissioning I. Vila 2nd CKM Workshop Durham

  21. SVT:Track Fitting I. Vila 2nd CKM Workshop Durham

  22. SVT for B0  1 MHz 1 kHz SVT 20 Hz 1 Hz picobarns • SVT reduces the background rate by a factor of 1000 • data recording possible by DAQ I. Vila 2nd CKM Workshop Durham

  23. Fake rate I. Vila 2nd CKM Workshop Durham

  24. Charm Xsec I. Vila 2nd CKM Workshop Durham

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