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Update on CDF Results on Diffraction

Update on CDF Results on Diffraction. K. Goulianos The Rockefeller University (Representing the CDF Collaboration) DIS 2005 27 April – 1 May Madison, Wisconsin. - p Interactions. Diffractive: vacuum exchange. Non-diffractive: color exchange. Protons retain their quantum numbers.

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Update on CDF Results on Diffraction

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  1. Update on CDF Results on Diffraction K. Goulianos The Rockefeller University (Representing the CDF Collaboration) DIS 2005 27 April – 1 May Madison, Wisconsin

  2. -p Interactions Diffractive: vacuum exchange Non-diffractive: color exchange Protons retain their quantum numbers Protons acquire color and break apart Goal: understand the nature of the colorless exchange New CDF Results on Diffraction K. Goulianos

  3. CDF Run 1-0 (1988-89) Elastic, single diffractive, and total cross sections @ 546 and 1800 GeV Roman Pot Spectrometers • Roman Pot Detectors • Scintillation trigger counters • Wire chamber • Double-sided silicon strip detector Additional Detectors Trackers up to |h| = 7 • Results • Total cross section stot ~ se • Elastic cross section ds/dt ~ exp[2a’ lns]  shrinking forward peak • Single diffraction Breakdown of Regge factorization New CDF Results on Diffraction K. Goulianos

  4. KG, PLB 358 (1995) 379 Run 1-0 results in perspective New CDF Results on Diffraction K. Goulianos

  5. Run-IC Run-IA,B Forward Detectors BBC 3.2<h<5.9 FCAL 2.4<h<4.2 CDF Run 1 (1992-1995) New CDF Results on Diffraction K. Goulianos

  6. Diffraction @ CDF in Run I 93(2004)141601 New CDF Results on Diffraction K. Goulianos

  7. Hd Fraction(%) W 1.15 (0.55) JJ 0.75 (0.10) b 0.62 (0.25) J/y 1.45 (0.25) Diffractive Fractions @ CDF Fraction: SD/ND ratio at 1800 GeV All ratios ~ 1% ~ uniform suppression ~ FACTORIZATION New CDF Results on Diffraction K. Goulianos

  8. R(SD/ND) vs xBj 0.035 < x < 0.095 Flat x dependence New CDF Results on Diffraction K. Goulianos

  9. Tevatron vs HERA:Breakdown of QCD Factorization H1 CDF New CDF Results on Diffraction K. Goulianos

  10. R(SD/ND) R(DPE/SD) Restoring Factorization The diffractive structure function measured on the proton side in events with a leading antiproton is NOT suppressed relative to predictions based on DDIS New CDF Results on Diffraction K. Goulianos

  11. Run 2 Diffractive Program • Single Diffraction • x and Q2 dependence of FjjD • Process dependence of FD (W, J/y) • Double Diffraction • Jet-Gap-Jet: Dhgap for fixed large Dhjet • Double Pomeron Exchange • FjjD on p-side vs x-pbar Also: Exclusive central production • Dijets, cc Other • Tev4LHC issues New CDF Results on Diffraction K. Goulianos

  12. SD and ND collisions Particle density Energy flow ND ND SD New CDF Results on Diffraction K. Goulianos

  13. ROMAN POT DETECTORS BEAM SHOWER COUNTERS: Used to reject ND events MINIPLUG CALORIMETER CDF-II New CDF Results on Diffraction K. Goulianos

  14. 84 towers 5.5 in 25 in Artist’s View of MiniPlug New CDF Results on Diffraction K. Goulianos

  15. MiniPlug Run II Data MiniPlug tower structure • ADC counts in MiniPlug towers • in a pbar-p event at 1960 GeV. • “jet” indicates an energy cluster • and may be just a hadron. Multiplicity distribution in SD and ND events New CDF Results on Diffraction K. Goulianos

  16. Diffractive Structure Function New CDF Results on Diffraction K. Goulianos

  17. Diffractive Dijet Sample overlap events New CDF Results on Diffraction K. Goulianos

  18. xRP vs xcal overlap events signal region xcal distribution for slice of xRP xcal = (0.94 ± 0.03) xRP s/mean ~ 30% New CDF Results on Diffraction K. Goulianos

  19. x10 • Ratio of SD/ND dijet event rates • agreement with Run 1 result • no x dependence in 0.03<x<0.1 • confirms Run I results x0.1 • No appreciable Q2 dependence • in region 100 < Q2 < 1,600 GeV2 • Pomeron evolves as proton MORE DATA CURRENTLY AT HAND Rjj New CDF Results on Diffraction K. Goulianos

  20. FjjD @ low x Measure x-dependence of Fjj(x,b,t) down to x~0.001 using gap trigger STATUS: Data at hand Analysis in progress New CDF Results on Diffraction K. Goulianos

  21. p p p p P P W W p p Diffractive W production Probes the quark content of the Pomeron  More direct comparison with HERA Run I: 8,246 W(ev) events - PRL 78 (1997), 2698 RW (SD/ND) = 1.15 ± 0.51(stat) ± 0.20(syst) % hard-gluon dominated Pomeron (rate lower by as) hard-quark dominated Pomeron Status: data at hand, analysis in progress New CDF Results on Diffraction K. Goulianos

  22. Question Gap Between Jets Is the diffractive exchange BFKL-like or simply a color rearrangement? Work in progress: low luminosity run needed New CDF Results on Diffraction K. Goulianos

  23. H Exclusive Dijet Production Use dijet rate to calibrate Higgs production calculations Khoze, Martin, Ryskin: Eur. Phys. J. C23, 311 (2002); C25,391 (2002);C26, 229 (2002) Boonekamp, Peschanski, Royon: PRL 87, 251806(2001) New CDF Results on Diffraction K. Goulianos

  24. Exclusive Dijets in Run 1 PRL 85 (2000) 4215 not detected Expected shape of signal events Mx Dijet Mass fraction Exclusive dijet limit: sjj (excl.) < 3.7 nb (95% CL) Theoretical expectation (KMR) ~1 nb New CDF Results on Diffraction K. Goulianos

  25. Run 2 dijet mass fraction exclusive? New CDF Results on Diffraction K. Goulianos

  26. Exclusive Dijet Events ? Rjj=0.36 Rjj=0.81 ETjet1(2) = 33(31) GeV ETjet1(2) = 36(33) GeV New CDF Results on Diffraction K. Goulianos

  27. Limits on Exclusive production Martin, Kaidalov, Khoze, Ryskin, Stirling hep-ph/0409258): ~ 40 pb (ET>25 GeV) (factor ~2 uncertainty) New CDF Results on Diffraction K. Goulianos

  28. Theory: JZ= 0 spin selection rule gg→gg dominant contribution at LO gg→qq suppressed when Mjj>> mq Heavy flavor exclusive dijets Experimental method: normalize Rjj(qq) to Rjj(all jets)  look for suppression at large Rjj Pros: many systematics cancel out good HF quark id small g mistag O(1%) Cons: heavy quark mass: suppression is not complete illustration New CDF Results on Diffraction K. Goulianos

  29. Heavy flavor tagged dijet fraction • exclusive production? • need: • to compare with MC • more data ! Rbtag(Rjj>0.7)/Rbtag(Rjj <0.4)=0.59 ± 0.33 (stat) ± 0.23 (syst) New CDF Results on Diffraction K. Goulianos

  30. cc From inclusive J/y data: Cross section upper limit: sexcl (J/y+g) = 49 ± 18(stat) ± 39(syst) pb Khoze, Martin, Ryskin, and Stirling ~ 70 pb [Eur. Phys. J. C 35, 211 (2004)] STATUS: data from new gap + J/y + gap trigger are being analyzed Exclusive cC New CDF Results on Diffraction K. Goulianos

  31. CONCLUSION Run 2 • CDF has a comprehensive Run 2 diffractive program • Data at hand are being analyzed • More data are being collected • Proposal for low luminosity (~1030) run under study Beyond Run 2 • Tev4LHC studies New CDF Results on Diffraction K. Goulianos

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