K. Goulianos The Rockefeller University Diffractive and Total Cross Tevatron and LHC HCP 2006 Duke University, NC, USA, May 2006  CDF results are presented on behalf of the CDF Collaboration 

HCP 2006, Duke U, May 22-26Diffractive ant Total Cross Tevatron and LHC K. Goulianos2 Contents  Introduction  Total Cross Sections  Diffraction  Exclusive Production

HCP 2006, Duke U, May 22-26Diffractive ant Total Cross Tevatron and LHC K. Goulianos3 p-p Interactions Diffractive: Colorless exchange with vacuum quantum numbers Non-diffractive: Color-exchange Incident hadrons retain their quantum numbers remaining colorless pseudo- DECONFINEMENT Incident hadrons acquire color and break apart CONFINEMENT POMERONPOMERON Goal: understand the QCD nature of the diffractive exchange rapidity gap

HCP 2006, Duke U, May 22-26Diffractive ant Total Cross Tevatron and LHC K. Goulianos4 Elastic Scattering

HCP 2006, Duke U, May 22-26Diffractive ant Total Cross Tevatron and LHC K. Goulianos5 Diffraction Dissociation Momentum loss fraction COHERENCE CONDITION  < M X  600 LHC  4.4 TeV

HCP 2006, Duke U, May 22-26Diffractive ant Total Cross Tevatron and LHC K. Goulianos6 Rapidity Gaps p p X p pp Particle productionRapidity gap   -ln  ln M X 2 ln s X

HCP 2006, Duke U, May 22-26Diffractive ant Total Cross Tevatron and LHC K. Goulianos7 Diffractive pp Processes   Elastic scatteringTotal cross section SD DDDPESDD=SD+DD  T =Im f el (t=0) OPTICAL THEOREM   GAP

HCP 2006, Duke U, May 22-26Diffractive ant Total Cross Tevatron and LHC K. Goulianos8 Rapidity Gaps in Fireworks

HCP 2006, Duke U, May 22-26Diffractive ant Total Cross Tevatron and LHC K. Goulianos9 The Physics  Elastic and Total Cross Sections:……….pp  pp and pp  X Fundamental Quantum Mechanics  Froissart Unitarity Bound……….  T < C ln 2 s  Optical theorem………………………..  T ~Im f(t=0)  Dispersion relations………………....Re f(t=0)~Im f(t=0)  Is space-time discrete?  Measure the  -value at the LHC!  Diffraction Dissociation:………………pp  pX, pp  pXp, pp  XGX, pp  pXGX Non-perturbative QCD  Soft & hard diffraction  Factorization  Multi-gap diffraction  Diffraction in QCD:…….……what is the Pomeron?  Dark energy?  Exclusive Production:………………….…..pp  pp+A (jet+jet, , …, H 0 ) Discovery channel  Diffractive Higgs production at the LHC (?)

HCP 2006, Duke U, May 22-26Diffractive ant Total Cross Tevatron and LHC K. Goulianos10 Tevatron Experiments Info Exp Roman Pots El TT Soft diffraction Hard diffraction E710/811 (Scint. Counters) p, pbar xxsd CDF-0 p, pbar xxsd CDF-Ipbarsd,dd,dpe,sddJJ,b,J/ ,W,JGJ CDF-IIpbarsd JJ,W,Z,JGJ Exclusive JJ,  D0-IJJ,W,Z,JGJ, … D0-II p, pbar xxsd,dpe,… JJ,W,Z,JGJ,… Exclusive ???

HCP 2006, Duke U, May 22-26Diffractive ant Total Cross Tevatron and LHC K. Goulianos11 CDF Run 1-0 ( ) Elastic, diffractive, and total cross 546 and 1800 GeV Roman Pot Spectrometers Roman Pot Detectors  Scintillation trigger counters  Wire chamber  Double-sided silicon strip detector Roman Pots with Trackers up to |  | = 7 CDF-I

HCP 2006, Duke U, May 22-26Diffractive ant Total Cross Tevatron and LHC K. Goulianos12 CDF-I Run-ICRun-IA,B Forward Detectors BBC 3.2<  <5.9 FCAL 2.4<  <4.2 beam

HCP 2006, Duke U, May 22-26Diffractive ant Total Cross Tevatron and LHC K. Goulianos13 CDF-II ROMAN POT DETECTORS BEAM SHOWER COUNTERS: Used to reject ND events MINIPLUG CALORIMETER

HCP 2006, Duke U, May 22-26Diffractive ant Total Cross Tevatron and LHC K. Goulianos14 CDF & D0 - Run II Z(m) D S Q2Q2 Q3Q3 Q4Q4 S A1A1 A2A2 P 1U P 2I P 2O P 1D D2 D Q4Q4 Q3Q3 Q2Q2 From Barreto’s talk in small-x D0 LM 2.5<η<4.4 VC 5.2<η<5.9 Z(m) p D Q2Q2 Q3Q3 Q4Q4 p RP3RP Q4Q4 Q3Q3 Q2Q2 MP 3.5<η<5.5 BSC1 5.5<η<7.5 RP2 SS BSC4 BSC2 BSC3BSC2 BSC3 CDF CDF & D0: COMPLIMENTARY COVERAGE

HCP 2006, Duke U, May 22-26Diffractive ant Total Cross Tevatron and LHC K. Goulianos15 ELASTIC AND TOTAL CROSS SECTIONS At Tevatron: CDF and E710/811  use luminosity independent method Optical theorem Alert:  background N inel yields small  T  undetected N inel yields large  T optical theorem

HCP 2006, Duke U, May 22-26Diffractive ant Total Cross Tevatron and LHC K. Goulianos16  T and  -values from PDG E710  = ratio of real/imaginary parts of elastic scattering amplitude at t =0 E811 CDF CDF and E710/811 disagree CDF & UA4  T optical theorem Im f el (t=0) dispersion relations Re f el (t=0) E811 N. Khuri and A. Martin: measuring  at the LHC tests discreteness of space-time

HCP 2006, Duke U, May 22-26Diffractive ant Total Cross Tevatron and LHC K. Goulianos17 Total Cross Sections: Regge fit CMG: Covolan, Montagna, and G PLB 389 (1995) 176 Simultaneous Regge fit to pp,  p, and Kp x-sections using the eikonal approach to ensure unitarity   S   = /   LHC = 115 TeV Born level DL E710 CDF

HCP 2006, Duke U, May 22-26Diffractive ant Total Cross Tevatron and LHC K. Goulianos18 Elastic/Total and  -values: Regge fit Covolan, Montagna, and G PLB 389 (1995) 176  Agreement with data on:  b-slopes   el /  T   -values  Unitarity assured

HCP 2006, Duke U, May 22-26Diffractive ant Total Cross Tevatron and LHC K. Goulianos19 Other Approaches  T (LHC) = ± 1.2 mb eg, M. Block, arXiv:hep-ph/ (2006)  fit data using analyticity constraints M. Block and F. Halzen, Phys. Rev. D 72, Recall CMG Regge fit: 115 mb

HCP 2006, Duke U, May 22-26Diffractive ant Total Cross Tevatron and LHC K. Goulianos20 TOTEM LHC Total Cross Section, Elastic Scattering, and Diffraction Dissociation Aim at 1% accuracy on  T RP stations CMS

HCP 2006, Duke U, May 22-26Diffractive ant Total Cross Tevatron and LHC K. Goulianos21 DIFFRACTION  Soft & hard diffraction  Factorization / renormalization  Multi-gap diffraction  Diffraction in QCD  Dark energy ???

HCP 2006, Duke U, May 22-26Diffractive ant Total Cross Tevatron and LHC K. Goulianos22  Regge theory  SD exceeds  T at  Renormalization Pomeron flux integral (re)normalized to unity A unitarity issue KG, PLB 358 (1995) 379 Pomeron flux Factorization 

HCP 2006, Duke U, May 22-26Diffractive ant Total Cross Tevatron and LHC K. Goulianos23 A Scaling Law in Diffraction KG&JM, PRD 59 (1999) Factorization breaks down so as to ensure M 2 -scaling! renormalization 1  Independent of S over 6 orders of magnitude in M 2 !

HCP 2006, Duke U, May 22-26Diffractive ant Total Cross Tevatron and LHC K. Goulianos24 The QCD Connection y  The exponential rise of  T (  y’) is due to the increase of wee partons with  y’ (E. Levin, An Introduction to Pomerons,Preprint DESY ) y  Total cross section: power law increase versus s Elastic cross section: forward scattering amplitude  s

HCP 2006, Duke U, May 22-26Diffractive ant Total Cross Tevatron and LHC K. Goulianos25 2 independent variables: Gap probability Renormalization removes the s-dependence SCALING Single Diffraction in QCD t color factor (KG, hep-ph/ )

HCP 2006, Duke U, May 22-26Diffractive ant Total Cross Tevatron and LHC K. Goulianos26 Multi-gap Renormalization Same suppression as for single gap! 5 independent variables Gap probabilitySub-energy cross section (for regions with particles) color factors (KG, hep-ph/ )

HCP 2006, Duke U, May 22-26Diffractive ant Total Cross Tevatron and LHC K. Goulianos27  Double Diffraction Dissociation  One central gap  Double Pomeron Exchange  Two forward gaps  SDD: Single+Double Diffraction  One forward + one central gap Central and Double CDF

HCP 2006, Duke U, May 22-26Diffractive ant Total Cross Tevatron and LHC K. Goulianos28  One-gap cross sections are suppressed  Two-gap/one-gap ratios are Central & Double-Gap CDF Results Differential shapes agree with Regge predictions DDSDDDPE

HCP 2006, Duke U, May 22-26Diffractive ant Total Cross Tevatron and LHC K. Goulianos29 Dark Energy P(  y) is exponentially suppressed Rapidity gaps are formed by multiplicity fluctuations: Non-diffractive interactions Rapidity gaps at t=0 grow with  y: Diffractive interactions 2  : negative particle density! Gravitational repulsion ?

HCP 2006, Duke U, May 22-26Diffractive ant Total Cross Tevatron and LHC K. Goulianos30 HARD DIFFRACTION  Diffractive fractions  Diffractive structure function  factorization breakdown  Restoring factorization  Hard diffraction in QCD  dN/d  JJ, W, b, J/ 

HCP 2006, Duke U, May 22-26Diffractive ant Total Cross Tevatron and LHC K. Goulianos31 All ratios ~ 1%  ~ uniform suppression ~ FACTORIZATION ! Diffractive CDF 1.45 (0.25)J/  0.62 (0.25)b 0.75 (0.10)JJ 1.15 (0.55)W Fraction(%) Fraction: SD/ND ratio at 1800 GeV

HCP 2006, Duke U, May 22-26Diffractive ant Total Cross Tevatron and LHC K. Goulianos32 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! Diffractive Structure Function: Breakdown of QCD Factorization CDF H1  = momentum fraction of parton in Pomeron Using preliminary pdf’s from

HCP 2006, Duke U, May 22-26Diffractive ant Total Cross Tevatron and LHC K. Goulianos33 Restoring QCD Factorization R(SD/ND) R(DPE/SD) DSF from two/one gap: factorization restored! The diffractive structure function measured on the proton side in events with a leading antiproton is NOT suppressed relative to predictions based on DDIS

HCP 2006, Duke U, May 22-26Diffractive ant Total Cross Tevatron and LHC K. Goulianos34 Diffractive Structure Function: Q 2 dependence E T jet ~ 100 GeV ! Small Q 2 dependence in region 100 < Q 2 < 10,000 GeV 2  Pomeron evolves as the proton!

HCP 2006, Duke U, May 22-26Diffractive ant Total Cross Tevatron and LHC K. Goulianos35 Diffractive Structure Function: t- dependence  No diffraction dips  No Q2 dependence in slope from inclusive to Q 2 ~10 4 GeV 2 Fit d  /dt to a double exponential:  Same slope over entire region of 0 < Q 2 < 4,500 GeV 2 across soft and hard diffraction!

HCP 2006, Duke U, May 22-26Diffractive ant Total Cross Tevatron and LHC K. Goulianos36 valence quarks antiproton x=x= Hard Diffraction in QCD proton deep sea Derive diffractive from inclusive PDFs and color factors antiproton valence quarks p p

HCP 2006, Duke U, May 22-26Diffractive ant Total Cross Tevatron and LHC K. Goulianos37 EXCLUSIVE PRODUCTION H Measure exclusive jj &     Calibrate predictions for H production 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/ B. Cox, A. Pilkington, PRD 72, (2005) OTHER………………………… Search for exclusive dijets: Measure dijet mass fraction Look for signal as M jj  1 Search for exclusive  Search for events with two high E T gammas and no other activity in the calorimeters or BSCs KMR:  H (LHC) ~ 3 fb S/B ~ 1 if  M ~ 1 GeV Clean discovery channel

HCP 2006, Duke U, May 22-26Diffractive ant Total Cross Tevatron and LHC K. Goulianos38 Exclusive Dijet and  Search b-taqged dijet fraction Dijet fraction – all jets Exlusive b-jets are suppressed by J Z = 0 selection rule Excess over MC predictions at large dijet mass fraction Systematic uncertainties under study: tune in this summer for results Exclusive  Based on 3 events observed: Good agreement with KMR: DIJETSDIJETS

HCP 2006, Duke U, May 22-26Diffractive ant Total Cross Tevatron and LHC K. Goulianos39 Looking LHC TOTEM/CMS ATLAS FP420 project Measure protons at 420 m from the IP during normal high luminosity running to be used in conjunction with CMS and ATLAS Feasibility study and R&D for Roman Pot detector development  Physics aim :pp  p+ X + p (Higgs, New physics, QCD studies)  Status: Project funded by the UK

HCP 2006, Duke U, May 22-26Diffractive ant Total Cross Tevatron and LHC K. Goulianos40 Summary TEVATRON – what we have learnt  M 2 – 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  Elastic and total cross sections &  -value  High mass  4 TeV and multi-gap diffraction  Exclusive production (FP420 project)  Reduced bgnd for std Higgs to study properties  Discovery channel for certain Higgs scenarios