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Results from CDF on Diffraction

Results from CDF on Diffraction. K. Goulianos The Rockefeller University.  presented on behalf of the CDF collaboration . Workshop on Low x Physics Lisbon, Portugal, 28 June – 1 July, 2006. Contents. Introduction & Run I results Run II results Exclusive Production

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Results from CDF on Diffraction

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  1. Results from CDF on Diffraction K. Goulianos The Rockefeller University  presented on behalf of the CDF collaboration Workshop on Low x PhysicsLisbon, Portugal,28 June – 1 July, 2006

  2. Contents • Introduction & Run I results • Run II results • Exclusive Production • Diffractive structure function Results from CDF on DiffractionK. Goulianos

  3. Incident hadrons acquire color and break apart POMERON CONFINEMENT p-p Interactions Non-diffractive: Color-exchange Diffractive: Colorless exchange with vacuum quantum numbers rapidity gap Incident hadrons retain their quantum numbers remaining colorless pseudo- DECONFINEMENT Goal: understand the QCD nature of the diffractive exchange Results from CDF on DiffractionK. Goulianos

  4. xp p p p X X Momentum loss fraction Rapidity Gaps ln s f Particle production Rapidity gap ln MX2 -ln x h Results from CDF on DiffractionK. Goulianos

  5. Diffraction @ CDF sT=Im fel (t=0) Elastic scattering Total cross section f f OPTICAL THEOREM GAP h h DD DPE SDD=SD+DD SD Results from CDF on DiffractionK. Goulianos

  6. Gaps in the sky! Results from CDF on DiffractionK. Goulianos

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

  8. Renormalization Factorization  Pomeron flux • Regge theory sSD exceeds sT at • Renormalization Pomeron flux integral (re)normalized to unity KG, PLB 358 (1995) 379 Results from CDF on DiffractionK. Goulianos

  9. renormalization 1 A Scaling Law in Diffraction KG&JM, PRD 59 (1999) 114017  Independent of S over 6 orders of magnitude in M2 ! Factorization breaks down so as to ensure M2-scaling! Results from CDF on DiffractionK. Goulianos

  10. f y The QCD Connection f Total cross section: power law increase versus s y ~1/as The exponential rise of sT(Dy’) is due to the increase of wee partons with Dy’ (E. Levin, An Introduction to Pomerons,Preprint DESY 98-120) Elastic cross section: forward scattering amplitude Results from CDF on DiffractionK. Goulianos

  11. Single Diffraction in QCD (KG, hep-ph/0205141) t 2 independent variables: color factor Gap probability Renormalization removes the s-dependence SCALING Results from CDF on DiffractionK. Goulianos

  12. 5 independent variables color factors Gap probability Sub-energy cross section (for regions with particles) Same suppression as for single gap! Multi-gap Renormalization (KG, hep-ph/0205141) Results from CDF on DiffractionK. Goulianos

  13. CDF-IA, IB beam Forward Detectors BBC 3.2<h<5.9 FCAL 2.4<h<4.2 Results from CDF on DiffractionK. Goulianos

  14. Central and Double Gaps • Double Diffraction Dissociation • One central gap • Double Pomeron Exchange • Two forward gaps • SDD: Single+Double Diffraction • One forward + one central gap Results from CDF on DiffractionK. Goulianos

  15. Differential shapes agree with Regge predictions DD SDD DPE • One-gap cross sections are suppressed • Two-gap/one-gap ratios are Central & Double-Gap CDF Results Results from CDF on DiffractionK. Goulianos

  16. CDF-IC beam Forward Detectors BBC 3.2<h<5.9 FCAL 2.4<h<4.2 Results from CDF on DiffractionK. Goulianos

  17. dN/dh h HARD DIFFRACTION • Diffractive fractions • Diffractive structure function  factorization breakdown • Restoring factorization • Hard diffraction in QCD JJ, W, b, J/y Results from CDF on DiffractionK. Goulianos

  18. Diffractive Fractions Fraction(%) Fraction: SD/ND ratio at 1800 GeV All ratios ~ 1% ~ uniform suppression ~ FACTORIZATION ! W 1.15 (0.55) JJ 0.75 (0.10) b 0.62 (0.25) J/y 1.45 (0.25) Results from CDF on DiffractionK. Goulianos

  19. Diffractive Structure Function:Breakdown of QCD Factorization b = momentum fraction of parton in Pomeron The diffractive structure function at the Tevatron is suppressed by a factor of ~10 relative to expectation from pdf’s measured by H1 at HERA Similar suppression factor as in soft diffraction relative to Regge expectations! H1 CDF Using preliminary pdf’s from Results from CDF on DiffractionK. Goulianos

  20. R(SD/ND) R(DPE/SD) DSF from two/one gap: factorization restored! Restoring QCD 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 Results from CDF on DiffractionK. Goulianos

  21. ROMAN POT DETECTORS BEAM SHOWER COUNTERS: Used to reject ND events MINIPLUG CALORIMETER CDF-II Results from CDF on DiffractionK. Goulianos

  22. The MiniPlugs @ CDF Results from CDF on DiffractionK. Goulianos

  23. MiniPlug Calorimeter About 1500 wavelength shifting fibers of 1 mm dia. are ‘strung’ through holes drilled in 36x¼” lead plates sandwiched between reflective Al sheets and guided into bunches to be viewed individually by multi-channel photomultipliers. Results from CDF on DiffractionK. Goulianos

  24. Run II Results • Diffractive structure function • Q2 - dependence • t - dependence • Exclusive production • dijet • diphoton Results from CDF on DiffractionK. Goulianos

  25. Diffractive Dijet Signal • - Bulk of data taken with RPS trigger but no working RPS tracking • Extract x from calorimetric information • Calibrate calorimetric x using limited sample of RPS tracking data • Subtract overlap background using a rescaled dijet event sample • Verify diffractive x range by comparing xRPS with xCAL Overlap events: mainly ND dijets plus SD low x RPS trigger Results from CDF on DiffractionK. Goulianos

  26. xCAL Calibration overlap events signal region xcal distributionfor slice of xRPS / mean ~ 30% Results from CDF on DiffractionK. Goulianos

  27. jet p jet p Dijet Properties SD boosted opposite to pbar Results from CDF on DiffractionK. Goulianos

  28. Alignment of RPS using Data maximize the |t|-slope  determine X and Y offsets Results from CDF on DiffractionK. Goulianos

  29. Diffractive Structure Function:Q2 dependence ETjet ~ 100 GeV ! • Small Q2 dependence in region 100 < Q2 < 10,000 GeV2 • Pomeron evolves similarly to proton! Results from CDF on DiffractionK. Goulianos

  30. Diffractive Structure Function:t- dependence Fit ds/dt to a double exponential: • No diffraction dips • No Q2 dependence in slope from inclusive to Q2~104 GeV2 • Same slope over entire region of 0 < Q2 < 10,000 GeV2 across soft and hard diffraction! Results from CDF on DiffractionK. Goulianos

  31. H EXCLUSIVE PRODUCTION Measure exclusive jj & gg  Calibrate predictions for H production rates @ LHC Bialas, Landshoff, Phys.Lett. B 256,540 (1991) Khoze, Martin, Ryskin, Eur. Phys. J. C23, 311 (2002); C25,391 (2002);C26,229 (2002) C. Royon, hep-ph/0308283 B. Cox, A. Pilkington, PRD 72, 094024 (2005) OTHER………………………… KMR: sH(LHC) ~ 3 fb S/B ~ 1 if DM ~ 1 GeV Clean discovery channel Search for exclusive gg Search for events with two high ET gammas and no other activity in the calorimeters or BSCs Search for exclusive dijets: Measure dijet mass fraction Look for signal as Mjj 1 Results from CDF on DiffractionK. Goulianos

  32. Exclusive Dijet and gg Search Dijet fraction – all jets b-taqged dijet fraction DIJETS Exlusive b-jets are suppressed by JZ= 0 selection rule Excess over MC predictions at large dijet mass fraction Systematic uncertainties under study: tune in soon for results! Exclusive gg Based on 3 events observed: Good agreement with KMR: Results from CDF on DiffractionK. Goulianos

  33. Dijets: Data vs MC Exclusive DPE (DPEMC)  non-pQCD based on Regge theory ExHuME (KMR): gggg process  uses LO pQCD • Excess of events at high Rjj is well described by both exclusive dijet production models • Currently investigating the dependence of the cross section on second jet ET to differentiate between the two models Results from CDF on DiffractionK. Goulianos

  34. Exclusive Dijet Signal COMPARISON inclusive data vs MC @ b/c-jet data vs inclusive Results from CDF on DiffractionK. Goulianos

  35. Exclusive gg/ee Search QED process: cross-check to exclusive gg • (anti)proton not detected • require 2 EM showers (ET>5 GeV, |h|<2) • veto on all BSCs and all calorimetery except for the 2 EM showers • L~530 pb-1 delivered  Leffective=46 pb-1 •  19 events with 2 EM showers + ”nothing” [above threshold] Results from CDF on DiffractionK. Goulianos

  36. Exclusive ee Search control sample for gg search ET1=6.1 GeV ET2=6.0 GeV 16 candidate events found background: good agreement with LPAIR: Results from CDF on DiffractionK. Goulianos

  37. Exclusive ggSearch  3 candidate events found background: ET1=6.8 GeV/c ET2=5.9 GeV/c good agreement with KMR:  sH ~ 10 fb (if H exists) within a factor ~ 2-3 , higher in MSSM Results from CDF on DiffractionK. Goulianos

  38. Non-diffractive interactions Diffractive interactions Rapidity gaps are formed by multiplicity fluctuations: Rapidity gaps at t=0 grow with Dy: 2e: negative particle density! P(Dy) is exponentially suppressed Gravitational repulsion? Dark Energy Results from CDF on DiffractionK. Goulianos

  39. Summary TEVATRON – what we have learnt • M2 – scaling • Non-suppressed double-gap to single-gap ratios • Pomeron: composite object made up from underlying pdf’s subject to color constraints LHC - what to do • High mass ( 4 TeV !)and multi-gap diffraction • Exclusive production  Reduced bgnd for std Higgs to study properties  Discovery channel for certain Higgs scenarios Results from CDF on DiffractionK. Goulianos

  40. BACKUP Results from CDF on DiffractionK. Goulianos

  41. p jet x x,t IP g* p e g* Q2 e reorganize Diffractive DIS:two models Particle-like Pomeron Color reorganization what is the Pomeron structure? probing the proton structure! Results from CDF on DiffractionK. Goulianos

  42. F2 ~ x-l eq Inclusive vs Diffractive DIS KG, “Diffraction: a New Approach,” J.Phys.G26:716-720,2000 e-Print Archive: hep-ph/0001092 Inclusive DIS Inclusive & diffr. DIS aP(0)-1 (eq+l)/2 Results from CDF on DiffractionK. Goulianos

  43. M. Arneodo, HERA/LHC workshop, CERN, 11-13 Oct 2004 ZEUS Fit including charm data H1 Fit without charm data Flat after subtracting Reggeon contribution DSF: H1 vs ZEUS H1 CDF Using preliminary pdf’s from Results from CDF on DiffractionK. Goulianos

  44. jet p jet reorganize Diffractive Dijets @ Tevatron eg~ 0.2  Agreement with data! Results from CDF on DiffractionK. Goulianos

  45. Pomeron dominated x-dependence: Inclusive vs Dijet Results from CDF on DiffractionK. Goulianos

  46. Question Gap Between Jets Results from CDF on DiffractionK. Goulianos

  47. valence quarks antiproton antiproton SOFT HARD eg=0.20 lg=0.5 eq=0. 04 lq=0.3 eR=-0.5 Diffraction from the Deep Sea deep sea valence quarks Derive diffractive from inclusive PDFs and color factors x=x proton Results from CDF on DiffractionK. Goulianos

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