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

ISMD 2004, K. Goulianos Diffraction from the Deep Sea 2 Introduction proton  g =0.20  q =0. 04  R =-0.5 g =0.5 q =0.3 in the deep sea

ISMD 2004, K. Goulianos Diffraction from the Deep Sea 3 Four Decades of Diffraction 1960’sGood and Walker BNL: first observation 1970’sFermilab fixed target, ISR, SPS Regge factorization works KG, Phys. Rep. 101, 169 (1983) 1980’sUA8: diff. dijets  hard diffraction  1990’sTevatron: Regge factorization breakdown TeV, HERA: QCD factorization breakdown

ISMD 2004, K. Goulianos Diffraction from the Deep Sea 4 Soft Diffraction POMERON: color singlet w/vacuum quantum numbers y  in QCD: KG, Phys. Rep. 101 (1983) 171 X 1/M 2 law

ISMD 2004, K. Goulianos Diffraction from the Deep Sea 5 Total & Elastic Cross Sections y  The exponential rise of  T (  y’) is due to the increase of wee partons with  y’ (see E. Levin, An Introduction to Pomerons,Preprint DESY ) y  QCD expectations

ISMD 2004, K. Goulianos Diffraction from the Deep Sea 6  Unitarity problem: With factorization and std pomeron flux  SD exceeds  T at  Renormalization: normalize the Pomeron flux to unity Renormalization KG, PLB 358 (1995) 379

ISMD 2004, K. Goulianos Diffraction from the Deep Sea 7 A Scaling Law in Diffraction KG&JM, PRD 59 (1999) Factorization breaks down in favor of M 2 -scaling renormalization 1

ISMD 2004, K. Goulianos Diffraction from the Deep Sea 8 2 independent variables: Gap probability Renormalization removes the s-dependence SCALING Partonic Basis of Renormalization t color factor (KG, hep-ph/ )

ISMD 2004, K. Goulianos Diffraction from the Deep Sea 9 The Factors  and  Experimentally: KG&JM, PRD 59 (114017) 1999 g =0.20 q =0.04 R =-0.5 f g =gluon fraction f q =quark fraction Color factor: Pomeron intercept: CTEQ5L

ISMD 2004, K. Goulianos Diffraction from the Deep Sea 10  Double Diffraction Dissociation  One central gap  Double Pomeron Exchange  Two forward gaps  SDD: Single+Double Diffraction  One forward + one central gap Central and Double Gaps

ISMD 2004, K. Goulianos Diffraction from the Deep Sea 11 Gap probabilitySub-energy cross section (for regions with particles) Generalized Renormalization Same suppression as for single gap! 5 independent variables color factors (KG, hep-ph/ )

ISMD 2004, K. Goulianos Diffraction from the Deep Sea 12  One-gap cross sections are suppressed  Two-gap/one-gap ratios are Central & Double-Gap Results Differential shapes agree with Regge predictions DDSDDDPE

ISMD 2004, K. Goulianos Diffraction from the Deep Sea 13 Soft Gap Survival Probability S =

ISMD 2004, K. Goulianos Diffraction from the Deep Sea 14 Soft Diffraction Conclusions  M 2 – scaling  Non-suppressed double-gap to single-gap ratios Experiment: Phenomenology:  Generalized renormalization  Obtain Pomeron intercept and tripe-Pomeron coupling from inclusive PDF’s and color factors

ISMD 2004, K. Goulianos Diffraction from the Deep Sea 15  SOFT DIFFRACTION Soft vs Hard Diffraction  HARD DIFFRACTION Additional variables: (x, Q 2 )  dN/d   =  P L /P L  =fractional momentum loss of scattered (anti)proton Variables: ( , t) or ( , t) MXMX  =-ln  t dN/d  ln M X 2

ISMD 2004, K. Goulianos Diffraction from the Deep Sea 16 CDF-I Run-ICRun-IA,B Forward Detectors BBC 3.2<  <5.9 FCAL 2.4<  <4.2

ISMD 2004, K. Goulianos Diffraction from the Deep Sea 17 Factorization Tevatron at 1800 GeV (single energy) ? All SD/ND fractions ~1% Gluon fraction Suppression by ~5 relative to HERA  gap survival probability ~20% Diffractive CDF 1.45 (0.25)J/  0.62 (0.25)b 0.75 (0.10)JJ 1.15 (0.55)W Fraction(%) X SD/ND fraction at 1800 GeVDD/ND gap fraction at 1800 GeV

ISMD 2004, K. Goulianos Diffraction from the Deep Sea 18 Difftactive Structure SD/ND Rates vs Measure ratio of SD/ND dijet rates as a f’n of In LO-QCD ratio of rates equals ratio of structure fn’s

ISMD 2004, K. Goulianos Diffraction from the Deep Sea 19 Breakdown of QCD Factorization  dN/d  gap e ** HERA TEVATRON  dN/d  gap pp IP  t CDF H1 pp IP p ??? The clue to understanding the Pomeron

ISMD 2004, K. Goulianos Diffraction from the Deep Sea 20 Restoring Diffractive Factorization R(SD/ND)R(DPE/SD) DSF from double-gaps: Factorization restored! DSF from single-gaps

ISMD 2004, K. Goulianos Diffraction from the Deep Sea 21 Q 2 dependence of DSF ~ no Q 2 dependence ~ flat at HERA ~ 1/ x 0.5 at Tevatron Pomeron evolves similarly to proton except for for renormalizartion effects

ISMD 2004, K. Goulianos Diffraction from the Deep Sea 22 Diffractive Structure Function from the Deep Sea Power-law region  max = 0.1 x max = 0.1  < 0.05   g =0.20  q =0. 04  R =-0.5 g =0.5 q =0.3

ISMD 2004, K. Goulianos Diffraction from the Deep Sea 23 Pomeron Intercept from H1 RENORM 1+

ISMD 2004, K. Goulianos Diffraction from the Deep Sea 24  -dependence: Inclusive vs Dijets g =0.5 q =0.3 Pomeron dominated

ISMD 2004, K. Goulianos Diffraction from the Deep Sea 25 Gap Between Jets Question

ISMD 2004, K. Goulianos Diffraction from the Deep Sea 26 Summary  M 2 – scaling  Non-suppressed double-gap to single-gap ratios  Flavor-independent SD/ND ratio  Little or no Q 2 -dependence in SD/ND ratio SOFT DIFFRACTION Universality of gap probability in soft and hard diffraction Pomeron evolves similarly to proton HARD DIFFRACTION Diffraction appears to be a low-x partonic exchange subject to color constraints