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Renormalized Diffractive Parton Densities and Exclusive Production

Renormalized Diffractive Parton Densities and Exclusive Production. K. Goulianos The Rockefeller University. Diffraction 2006 Milos island, Greece, 5-10 September 2006. Contents. Introduction Phenomenology Experiment confronts phenomenology Exclusive Production. POMERON.

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Renormalized Diffractive Parton Densities and Exclusive Production

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  1. Renormalized Diffractive Parton Densitiesand Exclusive Production K. Goulianos The Rockefeller University Diffraction 2006Milos island, Greece, 5-10 September 2006

  2. Contents • Introduction • Phenomenology • Experiment confronts phenomenology • Exclusive Production Renormalized Diffractive Parton Densities K. Goulianos

  3. POMERON p-p Interactions Non-diffractive: Color-exchange Diffractive: Colorless exchange with vacuum quantum numbers rapidity gap Incident hadrons acquire color and break apart Incident hadrons retain their quantum numbers remaining colorless Goal: develop a QCD based phenomenology for diffraction Renormalized Diffractive Parton Densities K. Goulianos

  4. xp p p p X X ln s f Particle production Rapidity gap ln MX2 -ln x h Diffractive Rapidity Gaps Renormalized Diffractive Parton Densities K. Goulianos

  5. x< 0.1 Diffraction Dissociation KG, Phys. Rep. 101, 169 (1983) Renormalized Diffractive Parton Densities K. Goulianos

  6. dN/dh h Factorization and scaling in soft single diffraction • Total SD cross section  factorization breakdown • M2-scaling  controls level of breakdown Renormalized Diffractive Parton Densities K. Goulianos

  7. Total Single Diffractive Cross Section • Unitarity problem: Using factorization and std pomeron flux sSD exceeds sT at • Renormalization: Normalize the Pomeron flux to unity KG, PLB 358 (1995) 379 Renormalized Diffractive Parton Densities K. Goulianos

  8. renormalization 1 M2-scaling 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! Renormalized Diffractive Parton Densities K. Goulianos

  9. Double Diffraction Dissociation  entral rapidity gaps  How does one apply Pomeron flux renormalization in this case?  Need generalized renormalization! Renormalized Diffractive Parton Densities K. Goulianos

  10. 450 BC 1869 Aristotle Demokritos Mendeleyev earth water air fire atom periodic table Plato (427-347 B.C) platonic love 2006 PHENOMENOLOGY Renormalized Diffractive Parton Densities K. Goulianos

  11. f y Total cross section: power law rise with energy ~1/as The exponential rise of sT(Dy’) is due to the increase of wee partons with Dy’ (see E. Levin, An Introduction to Pomerons,Preprint DESY 98-120) f Elastic cross section: forward scattering amplitude y Elastic and Total Cross Sections QCD expectations Renormalized Diffractive Parton Densities K. Goulianos

  12. t 2 independent variables: color factor Single Diffraction sub-energy x-section gap probability Gap probability MUST be normalized to unity! Renormalized Diffractive Parton Densities K. Goulianos

  13. Grows slower than se  The Pumplin bound is obeyed at all impact parameters Single diffraction (re)normalized Renormalized Diffractive Parton Densities K. Goulianos

  14. Color factor: Pomeron intercept: lg=0.20 lq=0.04 lR=-0.5 The Factors k and e Experimentally: KG&JM, PRD 59 (114017) 1999 CTEQ5L fg=gluon fraction fq=quark fraction Renormalized Diffractive Parton Densities K. Goulianos

  15. Multigap Diffraction (KG, hep-ph/0205141) f y Renormalized Diffractive Parton Densities K. Goulianos

  16. 5 independent variables color factor Gap probability Sub-energy cross section (for regions with particles) Multigap Cross Sections Same suppression as for single gap! Renormalized Diffractive Parton Densities K. Goulianos

  17. Diffractive Studies @ CDF sT=Im fel (t=0) Elastic scattering Total cross section f f OPTICAL THEOREM GAP h h DD DPE SDD=SD+DD SD Renormalized Diffractive Parton Densities K. Goulianos

  18. Agreement with renormalized Regge predictions DD SDD DPE • One-gap cross sections are suppressed • Two-gap/one-gap ratios are Central and Two-Gap CDF Results Renormalized Diffractive Parton Densities K. Goulianos

  19. S = Gap Survival Probability Results similar to predictions by: Gotsman-Levin-Maor Kaidalov-Khoze-Martin-Ryskin Soft color interactions Renormalized Diffractive Parton Densities K. Goulianos

  20. Lessons from Soft Diffraction • M2 – scaling  renormalization • Non-suppressed 2-gap to 1-gap ratios • Pomeron: composite object made up from underlying proton pdf’s subject to QCD color constraints Renormalized Diffractive Parton Densities K. Goulianos

  21. dN/dh h HARD DIFFRACTION • Diffractive structure function  factorization breakdown - how? • Restoring factorization • Diffractive fractions JJ, W, b, J/y Renormalized Diffractive Parton Densities K. Goulianos

  22. 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 expectations from Regge theory and factorization! H1 CDF Using preliminary pdf’s from Renormalized Diffractive Parton Densities K. Goulianos

  23. R(SD/ND) R(DPE/SD) Restoring Factorization @ Tevatron DSF from two/one gap: factorization restored! Renormalized Diffractive Parton Densities K. Goulianos

  24. ZEUS Fit including charm data H1 Fit without charm data FDJJ(b) from ZEUS-LPS Data From: M. Arneodo, HERA/LHC workshop, CERN, 11-13 Oct 2004 Flat after subtracting Reggeon contribution Renormalized Diffractive Parton Densities K. Goulianos

  25. dN/dh % Fraction (+/-) W 1.15 (0.55) JJ 0.75 (0.10) h b 0.62 (0.25) J/y 1.45 (0.25) Hard Diffractive Fractions @ CDF Fraction: SD/ND ratio at 1800 GeV All ratios ~ 1% ~ uniform suppression ~ FACTORIZATION ! Renormalized Diffractive Parton Densities K. Goulianos

  26. Diffractive Structure Function:Q2 dependence ETjet ~ 100 GeV ! • Small Q2 dependence in region 100 < Q2 < 10,000 GeV2 • Pomeron evolves as the proton! Renormalized Diffractive Parton Densities K. Goulianos

  27. Diffractive Structure Function:t- dependence Fit ds/dt to a double exponential: • Same slope over entire region of 0 < Q2 < 4,500 GeV2 across soft and hard diffraction! • No diffraction dips • No Q2 dependence in slope from inclusive to Q2~104 GeV2 Renormalized Diffractive Parton Densities K. Goulianos

  28. jet p x x,t IP p g* e g* Q2 e reorganize Diffractive DIS @ HERA J. Collins: factorization holds (but under what contitions?) Pomeron exchange Color reorganization Renormalized Diffractive Parton Densities K. Goulianos

  29. H1, ICHEP2006 F2 ~ x-l total error (eq+l)/2 eq Inclusive vs Diffractive DIS KG, “Diffraction: a New Approach,” J.Phys.G26:716-720,2000 e-Print Archive: hep-ph/0001092 Renormalized Diffractive Parton Densities K. Goulianos

  30. jet p jet reorganize Diffractive Dijets @ Tevatron Renormalized Diffractive Parton Densities K. Goulianos

  31. FDJJ(x,b,Q2) @ Tevatron Renormalized Diffractive Parton Densities K. Goulianos

  32. SD/ND Dijet Ratio vs xBj@ CDF 0.035 < x < 0.095 Flat x dependence Renormalized Diffractive Parton Densities K. Goulianos

  33. Gap Between Jets Renormalized Diffractive Parton Densities K. Goulianos

  34. p p valence quarks antiproton antiproton Hard Diffraction in QCD deep sea valence quarks Derive diffractive from inclusive PDFs and color factors x=x proton Renormalized Diffractive Parton Densities K. Goulianos

  35. p p H p p p p H p p Diffractive Higgs @ LHC Back of the envelope calculation Inclusive production • sD(LHC) ~ P(gap) x sND (Tevatron) ~ 0.1 x 1 pb = 100 fb Exclusive production • sexcl ~ sincl x 0.02~ 2 fb Fraction of 2/all particle multiplicity OTHER THEORETICAL PREDICTIONS Exclusive DPE Higgs production ppp H p : 3-10 fb (KMR) Inclusive DPE Higgs production ppp+X+H+Y+p : 50-200 fb (others) Renormalized Diffractive Parton Densities K. Goulianos

  36. SUMMARY Diffraction is an interaction between low-x partons subject to color constraints Renormalized Diffractive Parton Densities K. Goulianos

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