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Exploring Diffraction from the Deep Sea: Insights from High-Energy Physics Research

This presentation by Konstantin Goulianos discusses four decades of research on diffraction phenomena in particle physics, focusing on findings from experiments conducted at BNL, Fermilab, and the Tevatron. Key topics include the observation of soft and hard diffraction, the impact of QCD on cross-sections, and the significance of the Pomeron in explaining diffraction processes. Goulianos presents a comprehensive overview of scaling laws, renormalization techniques, and the breakdown of factorization in various scattering regimes, providing vital insights into the nature of partonic interactions.

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Exploring Diffraction from the Deep Sea: Insights from High-Energy Physics Research

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  1. DIFFRACTION FROM THE DEEP SEA ISMD 2004 Konstantin Goulianos The Rockefeller University 26 July – 1 August 2004 Sonoma County, California, USA

  2. proton lg=0.5 lq=0.3 in the deep sea eg=0.20 eq=0. 04 eR=-0.5 Introduction Diffraction from the Deep Sea

  3. Four Decades of Diffraction • 1960’s Good and Walker • BNL: first observation • 1970’s Fermilab fixed target, ISR, SPS • Regge factorization works • KG, Phys. Rep. 101, 169 (1983) • 1980’s UA8: diff. dijets a hard diffraction • 1990’s Tevatron: Regge factorization breakdown • TeV, HERA: QCD factorization breakdown Diffraction from the Deep Sea

  4. 1/M2 law in QCD: X f y POMERON: color singlet w/vacuum quantum numbers KG, Phys. Rep. 101 (1983) 171 Soft Diffraction Diffraction from the Deep Sea

  5. QCD expectations f y 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 y Total & Elastic Cross Sections Diffraction from the Deep Sea

  6. Renormalization • Unitarity problem: With factorization and std pomeron flux sSD exceeds sT at • Renormalization: normalize the Pomeron flux to unity KG, PLB 358 (1995) 379 Diffraction from the Deep Sea

  7. A Scaling Law in Diffraction KG&JM, PRD 59 (1999) 114017 Factorization breaks down in favor of M2-scaling renormalization 1 Diffraction from the Deep Sea

  8. color factor Partonic Basis of Renormalization (KG, hep-ph/0205141) t 2 independent variables: Gap probability Renormalization removes the s-dependence SCALING Diffraction from the Deep Sea

  9. 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 Diffraction from the Deep Sea

  10. 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 Diffraction from the Deep Sea

  11. 5 independent variables color factors Gap probability Sub-energy cross section (for regions with particles) Generalized Renormalization (KG, hep-ph/0205141) Same suppression as for single gap! Diffraction from the Deep Sea

  12. Differential shapes agree with Regge predictions DD SDD DPE • One-gap cross sections are suppressed • Two-gap/one-gap ratios are Central & Double-Gap Results Diffraction from the Deep Sea

  13. S = Soft Gap Survival Probability Diffraction from the Deep Sea

  14. Soft Diffraction Conclusions Experiment: • M2– scaling • Non-suppressed double-gap to single-gap ratios Phenomenology: • Generalized renormalization • Obtain Pomeron intercept and tripe-Pomeron coupling from inclusive PDF’s and color factors Diffraction from the Deep Sea

  15. SOFT DIFFRACTION HARD DIFFRACTION MX dN/dh dN/dh Dh=-lnx h ln MX2 t x=DPL/PL x=fractional momentum loss of scattered (anti)proton Additional variables: (x, Q2) Variables: (x, t) or (Dh, t) Soft vs Hard Diffraction Diffraction from the Deep Sea

  16. Run-IC Run-IA,B Forward Detectors BBC 3.2<h<5.9 FCAL 2.4<h<4.2 CDF-I Diffraction from the Deep Sea

  17. X 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 SD/ND fraction at 1800 GeV DD/ND gap fraction at 1800 GeV • All SD/ND fractions ~1% • Gluon fraction • Suppression by ~5 relative to HERA •  gap survival probability ~20% Factorization OK @ Tevatron at 1800 GeV (single energy) ? Diffraction from the Deep Sea

  18. Difftactive Structure F‘n @CDF • Measure ratio of SD/ND dijet rates as a f’n of • In LO-QCD ratio of rates equals ratio of structure fn’s SD/ND Rates vs Diffraction from the Deep Sea

  19. IP IP p p p p Breakdown of QCD Factorization The clue to understanding the Pomeron HERA TEVATRON p x,t IP g* H1 e CDF gap gap dN/dh dN/dh h h ??? Diffraction from the Deep Sea

  20. R(SD/ND) R(DPE/SD) DSF from double-gaps: Factorization restored! DSF from single-gaps Restoring Diffractive Factorization Diffraction from the Deep Sea

  21. ~ no Q2 dependence ~ flat at HERA ~ 1/x0.5 at Tevatron Q2 dependence of DSF Pomeron evolves similarly to proton except for for renormalizartion effects Diffraction from the Deep Sea

  22. lg=0.5 lq=0.3 Diffractive Structure Functionfrom the Deep Sea eg=0.20 Power-law region xmax = 0.1 xmax = 0.1 b < 0.05x eq=0. 04 eR=-0.5 Diffraction from the Deep Sea

  23. RENORM Pomeron Intercept from H1 1+l Diffraction from the Deep Sea

  24. lg=0.5 lq=0.3 Pomeron dominated x-dependence: Inclusive vs Dijets Diffraction from the Deep Sea

  25. Question Gap Between Jets Diffraction from the Deep Sea

  26. Summary SOFT DIFFRACTION • M2– scaling • Non-suppressed double-gap to single-gap ratios • Flavor-independent SD/ND ratio • Little or no Q2-dependence in SD/ND ratio HARD DIFFRACTION • Universality of gap probability in soft and hard diffraction • Pomeron evolves similarly to proton Diffraction appears to be a low-x partonic exchange subject to color constraints Diffraction from the Deep Sea

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