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Diffraction in Run I New Detectors for Run II Diffractive dijets: Q 2 dependence

Diffractive Physics at CDF II: diffractive structure function. Michele Gallinaro – The Rockefeller University (for the CDF collaboration) Small- x and Diffraction, Fermilab. Diffraction in Run I New Detectors for Run II Diffractive dijets: Q 2 dependence. Diffraction in Run I.

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Diffraction in Run I New Detectors for Run II Diffractive dijets: Q 2 dependence

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  1. Diffractive Physics at CDF II: diffractive structure function Michele Gallinaro – The Rockefeller University (for the CDF collaboration) Small-x and Diffraction, Fermilab • Diffraction in Run I • New Detectors for Run II • Diffractive dijets: Q2 dependence

  2. Diffraction in Run I • Large rapidity gaps are signatures for diffraction • Soft diffraction • SD • DD • DPE • multi-Gap control sample • Hard diffraction • SD (W, jet-jet, b-quark, J/y) • SD (w/RP) dijets (630 GeV and 1.8 TeV) • Forward jets (Jet-Gap-Jet) • DPE dijets SD dijets Michele Gallinaro, "Diffractive Results at CDF II" - Small-x and Diffraction, Fermilab, Sept. 17-20, 2003

  3. If you want to know more… for a review: hep-ph/0306085 …see Goulianos’ talk tomorrow ! Michele Gallinaro, "Diffractive Results at CDF II" - Small-x and Diffraction, Fermilab, Sept. 17-20, 2003

  4. First Goals for Run II • Diffractive structure function  Q2 and x dependence • Exclusive production  dijet, heavy flavor, low-mass Michele Gallinaro, "Diffractive Results at CDF II" - Small-x and Diffraction, Fermilab, Sept. 17-20, 2003

  5. Chicago  Booster CDF DØ Tevatron p source Main Injector (new) Tevatron Collider • Tevatron and detector upgrades • C.M. energy 1.96 TeV • 396 nsec bunch spacing • high (low ?) inst. luminosity • (L ~ 2-3 x 1031 cm-2sec-1) • multiple interactions Michele Gallinaro, "Diffractive Results at CDF II" - Small-x and Diffraction, Fermilab, Sept. 17-20, 2003

  6. New Detectors for Run II time-of-flight tracker • Tracking • Silicon • Central Outer Tracker • Time of Flight • Expanded Muon Coverage • Endplug Calorimeter • Forward Detectors • Trigger • Tracks @ L1 • Silicon Tracks @ L2 • DAQ (132 ns) MiniPlug calorimeter Michele Gallinaro, "Diffractive Results at CDF II" - Small-x and Diffraction, Fermilab, Sept. 17-20, 2003

  7. Forward Detectors • Roman Pots Spectrometer • Beam Shower Counters • MiniPlug Calorimeter  Larger h coverage for rapidity gaps and jets Michele Gallinaro, "Diffractive Results at CDF II" - Small-x and Diffraction, Fermilab, Sept. 17-20, 2003

  8. Beam Shower Counters L1 Trigger Beam Losses Michele Gallinaro, "Diffractive Results at CDF II" - Small-x and Diffraction, Fermilab, Sept. 17-20, 2003

  9. Roman Pot Spectrometer Fiber Tracker • 3 stations • 57 meters from IP • 3 trigger counters • 240 channels MIPs ( >1000 counts) Michele Gallinaro, "Diffractive Results at CDF II" - Small-x and Diffraction, Fermilab, Sept. 17-20, 2003

  10. New MiniPlug Calorimeter • liquid scintillator + lead • towerless geometry • full coverage: 3.5< || < 5.1 Measure: very forward jet energies and position multiplicity Michele Gallinaro, "Diffractive Results at CDF II" - Small-x and Diffraction, Fermilab, Sept. 17-20, 2003

  11. MiniPlug Design East MP (viewed from IP) Michele Gallinaro, "Diffractive Results at CDF II" - Small-x and Diffraction, Fermilab, Sept. 17-20, 2003

  12. Path to diffractive results • 2) Data • triggers are prescaled • more than 100 pb-1 collected • 1) Detectors • installed (MP/November 2001) • triggers implemented • fully instrumented • ready in September 2002 • 3) Results • what do we find? (what do you see?) • next Michele Gallinaro, "Diffractive Results at CDF II" - Small-x and Diffraction, Fermilab, Sept. 17-20, 2003

  13. Diffractive Dijets x: fraction of anti-proton momentum loss b: fraction of pomeron momentum carried by parton parton xBj  b . x (LO QCD) • CDF Run I result suppressed • by a factor of ~10 relative to HERA • breakdown of QCD factorization (renormalization removes s-dependence) • K. Goulianos, PLB 358 (1995) 379 Michele Gallinaro, "Diffractive Results at CDF II" - Small-x and Diffraction, Fermilab, Sept. 17-20, 2003

  14. Trigger • RP is triggered on leading antiprotons • Use RP + jet triggers require jets Michele Gallinaro, "Diffractive Results at CDF II" - Small-x and Diffraction, Fermilab, Sept. 17-20, 2003

  15. Event Samples Dedicated triggers  total rate ~3Hz Michele Gallinaro, "Diffractive Results at CDF II" - Small-x and Diffraction, Fermilab, Sept. 17-20, 2003

  16. x : Momentum Loss Fraction Measure fractional momentum loss of anti-proton MX 2 x = s S ETe-h  x = s Dy= ln (1/x) Diffractive events are boosted towards positive h  small x Michele Gallinaro, "Diffractive Results at CDF II" - Small-x and Diffraction, Fermilab, Sept. 17-20, 2003

  17. Single Diffractive Dijets • Compare diffractive events to ND • Measure diffractive structure function • from RSD/NDvsx Bj overlap events Measure x ( p momentum loss fraction) from calorimeter information Approx. flat at x<0.1 constant Michele Gallinaro, "Diffractive Results at CDF II" - Small-x and Diffraction, Fermilab, Sept. 17-20, 2003

  18. SD: Event Selection Data presented from 8 pb-1: • RP acceptance ~80% (from Run I) • negligible (< 1-2%) RP background trigger Michele Gallinaro, "Diffractive Results at CDF II" - Small-x and Diffraction, Fermilab, Sept. 17-20, 2003

  19. Kinematic Properties Compare ND and SD Michele Gallinaro, "Diffractive Results at CDF II" - Small-x and Diffraction, Fermilab, Sept. 17-20, 2003

  20. Ratio of SD/ND Events Sjet ET e-h xBj= s (jet=1,2,3 if ET>5 GeV) • slope and normalization agree with Run I result • work in progress to evaluate ratio at smaller x values Michele Gallinaro, "Diffractive Results at CDF II" - Small-x and Diffraction, Fermilab, Sept. 17-20, 2003

  21. Q2 dependence ET1+ ET2 ET* = 2 • select energy intervals • overall norm. only • no significant Q2 dependence Pomeron evolves similarly to proton (?) Michele Gallinaro, "Diffractive Results at CDF II" - Small-x and Diffraction, Fermilab, Sept. 17-20, 2003

  22. Summary • CDF forward detectors working well • dedicated diffractive triggers • re-established Run I measurements • no significant Q2 dependence in SD/ND ratio Run II analyses are well underway ! Michele Gallinaro, "Diffractive Results at CDF II" - Small-x and Diffraction, Fermilab, Sept. 17-20, 2003

  23. More CDF Run II results in the following talks… Michele Gallinaro, "Diffractive Results at CDF II" - Small-x and Diffraction, Fermilab, Sept. 17-20, 2003

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