1 / 23

QCD Results at CDF

QCD Results at CDF. Inclusive Jet Cross Section Dijet Mass Jet Shapes Diffractive Dijets. Chicago . Booster. CDF. DØ. Tevatron. p sou rce. Main Injector (new). Tevatron Collider. C.M. energy 1.96 TeV 396 nsec bunch spacing. inst. lum. 2-3 x 10 31 cm -2 sec -1

andreap
Télécharger la présentation

QCD Results at CDF

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. QCD Results at CDF • Inclusive Jet Cross Section • Dijet Mass • Jet Shapes • Diffractive Dijets Michele Gallinaro, "QCD Results at CDF" - XXXVIII Rencontres de Moriond, March 22-29, 2003

  2. Chicago  Booster CDF DØ Tevatron p source Main Injector (new) Tevatron Collider • C.M. energy 1.96 TeV • 396 nsec bunch spacing • inst. lum. 2-3 x 1031 cm-2sec-1 • delivered 4-7 pb-1 per week • goal: 12 pb-1 per week Michele Gallinaro, "QCD Results at CDF" - XXXVIII Rencontres de Moriond, March 22-29, 2003

  3. CDF II Detector • Tracking • Silicon • Central Outer Tracker • Time of Flight • Expanded Muon Coverage • Endplug Calorimeter • Forward Detectors • Trigger • Tracks @ L1 • Silicon Tracks @ L2 • DAQ (132 ns) Michele Gallinaro, "QCD Results at CDF" - XXXVIII Rencontres de Moriond, March 22-29, 2003

  4. QCD at the Tevatron • Tevatron Collider is a tool for precision tests of QCD • Compare to QCD predictions • Probe to small distance scales • Look for new physics • Higher center-of-mass energy than Run I • s = 1.96 TeV • Higher jet cross section Michele Gallinaro, "QCD Results at CDF" - XXXVIII Rencontres de Moriond, March 22-29, 2003

  5. Jet ET Spectrum Excess at high jet ET in Run I • Use cone algorithm • Different ET triggers • Use data when trigger is 99 % efficient Michele Gallinaro, "QCD Results at CDF" - XXXVIII Rencontres de Moriond, March 22-29, 2003

  6. Inclusive Jet Cross Section Continuous spectrum to higher Jet ET Systematic uncertainties Largest uncertainty (~ 5 %) Run II data extends Run I results by ~ 150 GeV Michele Gallinaro, "QCD Results at CDF" - XXXVIII Rencontres de Moriond, March 22-29, 2003

  7. Cross Section Fit Best fit to central jet cross section provided by CTEQ 6.1 Gluon distribution has large uncertainty in high x region Michele Gallinaro, "QCD Results at CDF" - XXXVIII Rencontres de Moriond, March 22-29, 2003

  8. Jet Cross Section vs h • QCD sub-processes at small angles • Central jets are more likely to signal new physics (hep-ph 0303013) Michele Gallinaro, "QCD Results at CDF" - XXXVIII Rencontres de Moriond, March 22-29, 2003

  9. Dijet Mass • Two highest ET jets • Search for resonances  Larger dijet mass events than in Run I Michele Gallinaro, "QCD Results at CDF" - XXXVIII Rencontres de Moriond, March 22-29, 2003

  10. High Dijet Mass Event Jet 1 ET = 666 GeV (corr) hdet = 0.31 Jet 2 ET = 633 GeV (corr) hdet = - 0.30 Run 152507 event 1222318 Dijet Mass = 1364 GeV (corr) CDF Run 2 Preliminary Michele Gallinaro, "QCD Results at CDF" - XXXVIII Rencontres de Moriond, March 22-29, 2003

  11. Dijet Mass Ratio: Run II/Run I Higher jet cross section than Run I  ratio agrees with theory to ~ 10 % in rate (~ 2 % in energy scale) Michele Gallinaro, "QCD Results at CDF" - XXXVIII Rencontres de Moriond, March 22-29, 2003

  12. Limits on New Particles • Search for new particles decaying to dijets. • Fit data to background • plus a narrow resonance • Calculate cross section • Find 95 % CL upper limit • Compare with theory  set upper limits on cross section Michele Gallinaro, "QCD Results at CDF" - XXXVIII Rencontres de Moriond, March 22-29, 2003

  13. Jet Shapes • Jets narrow at high ET • Herwig/Pythia agree well with data Michele Gallinaro, "QCD Results at CDF" - XXXVIII Rencontres de Moriond, March 22-29, 2003

  14. Forward Physics • Hard Single Diffraction • Double Pomeron Exchange Michele Gallinaro, "QCD Results at CDF" - XXXVIII Rencontres de Moriond, March 22-29, 2003

  15. 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 Michele Gallinaro, "QCD Results at CDF" - XXXVIII Rencontres de Moriond, March 22-29, 2003

  16. Ratio of SD/ND Events Ratio is independent of x interval Ratio is independent of Q2 Michele Gallinaro, "QCD Results at CDF" - XXXVIII Rencontres de Moriond, March 22-29, 2003

  17. Proton-Side Multiplicity (0,0) bin Michele Gallinaro, "QCD Results at CDF" - XXXVIII Rencontres de Moriond, March 22-29, 2003

  18. DPE Enhanced Sample • Use dedicated DPE trigger (RP+J5+GapE) • (0,0) bin  ~ 16,000 events (in Run I: ~ 100 evts) Michele Gallinaro, "QCD Results at CDF" - XXXVIII Rencontres de Moriond, March 22-29, 2003

  19. DPE: Kinematics Michele Gallinaro, "QCD Results at CDF" - XXXVIII Rencontres de Moriond, March 22-29, 2003

  20. Summary • Inclusive jet cross section extends beyond 550 GeV • Dijet mass up event up to 1364 GeV • First exclusion of new particle with mass > 1 TeV • Preliminary diffractive results show no Q2 dependence in SD/ND Run II analyses are well underway ! Michele Gallinaro, "QCD Results at CDF" - XXXVIII Rencontres de Moriond, March 22-29, 2003

  21. Backup Slides …TO FOLLOW… Michele Gallinaro, "QCD Results at CDF" - XXXVIII Rencontres de Moriond, March 22-29, 2003

  22. New Plug Calorimeter Scintillator + lead/steel (replaces gas detector) Full coverage up to || = 3.5 more precise measurement of forward jets Michele Gallinaro, "QCD Results at CDF" - XXXVIII Rencontres de Moriond, March 22-29, 2003

  23. New MiniPlug Calorimeter • Liquid Scintillator + lead • towerless geometry • Full coverage: 3.5< || < 5.1 Measure very forward jet energies Michele Gallinaro, "QCD Results at CDF" - XXXVIII Rencontres de Moriond, March 22-29, 2003

More Related