K. Goulianos The Rockefeller University Results from CDF on Diffraction presented on behalf of the CDF collaboration Workshop on Low x Physics Lisbon, Portugal, 28 June – 1 July, 2006
Low x 2006, Lisbon, Portugal, June 28 – July 2Results from CDF on Diffraction K. Goulianos2 Contents Introduction & Run I results Run II results Exclusive Production Diffractive structure function
Low x 2006, Lisbon, Portugal, June 28 – July 2Results from CDF on Diffraction 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
Low x 2006, Lisbon, Portugal, June 28 – July 2Results from CDF on Diffraction K. Goulianos4 Rapidity Gaps p p X p pp Particle productionRapidity gap -ln ln M X 2 ln s X Momentum loss fraction
Low x 2006, Lisbon, Portugal, June 28 – July 2Results from CDF on Diffraction K. Goulianos5 CDF Elastic scatteringTotal cross section SD DDDPESDD=SD+DD T =Im f el (t=0) OPTICAL THEOREM GAP
Low x 2006, Lisbon, Portugal, June 28 – July 2Results from CDF on Diffraction K. Goulianos6 Gaps in the sky!
Low x 2006, Lisbon, Portugal, June 28 – July 2Results from CDF on Diffraction K. Goulianos7 Run 1-0 ( ) Elastic, single diffractive, and total cross 546 and 1800 GeV Roman Pot Detectors Scintillation trigger counters Wire chamber Double-sided silicon strip detector Total cross section tot ~ s Elastic cross section d /dt ~ exp[2 ’ ln s ] shrinking forward peak Single diffraction Breakdown of Regge factorization Roman Pots with Trackers up to | | = 7 Roman Pot Spectrometers CDF-I
Low x 2006, Lisbon, Portugal, June 28 – July 2Results from CDF on Diffraction K. Goulianos8 Regge theory SD exceeds T at Renormalization Pomeron flux integral (re)normalized to unity Renormalization KG, PLB 358 (1995) 379 Pomeron flux Factorization
Low x 2006, Lisbon, Portugal, June 28 – July 2Results from CDF on Diffraction K. Goulianos9 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 !
Low x 2006, Lisbon, Portugal, June 28 – July 2Results from CDF on Diffraction K. Goulianos10 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
Low x 2006, Lisbon, Portugal, June 28 – July 2Results from CDF on Diffraction K. Goulianos11 2 independent variables: Gap probability Renormalization removes the s-dependence SCALING Single Diffraction in QCD t color factor (KG, hep-ph/ )
Low x 2006, Lisbon, Portugal, June 28 – July 2Results from CDF on Diffraction K. Goulianos12 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/ )
Low x 2006, Lisbon, Portugal, June 28 – July 2Results from CDF on Diffraction K. Goulianos13 CDF-IA, IB Forward Detectors BBC 3.2< <5.9 FCAL 2.4< <4.2 beam
Low x 2006, Lisbon, Portugal, June 28 – July 2Results from CDF on Diffraction K. Goulianos14 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
Low x 2006, Lisbon, Portugal, June 28 – July 2Results from CDF on Diffraction K. Goulianos15 One-gap cross sections are suppressed Two-gap/one-gap ratios are Central & Double-Gap CDF Results Differential shapes agree with Regge predictions DDSDDDPE
Low x 2006, Lisbon, Portugal, June 28 – July 2Results from CDF on Diffraction K. Goulianos16 CDF-IC Forward Detectors BBC 3.2< <5.9 FCAL 2.4< <4.2 beam
Low x 2006, Lisbon, Portugal, June 28 – July 2Results from CDF on Diffraction K. Goulianos17 HARD DIFFRACTION Diffractive fractions Diffractive structure function factorization breakdown Restoring factorization Hard diffraction in QCD dN/d JJ, W, b, J/
Low x 2006, Lisbon, Portugal, June 28 – July 2Results from CDF on Diffraction K. Goulianos18 All ratios ~ 1% ~ uniform suppression ~ FACTORIZATION ! Diffractive Fractions 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
Low x 2006, Lisbon, Portugal, June 28 – July 2Results from CDF on Diffraction K. Goulianos19 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
Low x 2006, Lisbon, Portugal, June 28 – July 2Results from CDF on Diffraction K. Goulianos20 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
Low x 2006, Lisbon, Portugal, June 28 – July 2Results from CDF on Diffraction K. Goulianos21 CDF-II ROMAN POT DETECTORS BEAM SHOWER COUNTERS: Used to reject ND events MINIPLUG CALORIMETER
Low x 2006, Lisbon, Portugal, June 28 – July 2Results from CDF on Diffraction K. Goulianos22 The CDF
Low x 2006, Lisbon, Portugal, June 28 – July 2Results from CDF on Diffraction K. Goulianos23 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.
Low x 2006, Lisbon, Portugal, June 28 – July 2Results from CDF on Diffraction K. Goulianos24 Run II Results Diffractive structure function Q 2 - dependence t - dependence Exclusive production dijet diphoton
Low x 2006, Lisbon, Portugal, June 28 – July 2Results from CDF on Diffraction K. Goulianos25 Diffractive Dijet Signal Overlap events: mainly ND dijets plus SD low RPS trigger - Bulk of data taken with RPS trigger but no working RPS tracking - Extract from calorimetric information - Calibrate calorimetric using limited sample of RPS tracking data - Subtract overlap background using a rescaled dijet event sample - Verify diffractive range by comparing RPS with CAL
Low x 2006, Lisbon, Portugal, June 28 – July 2Results from CDF on Diffraction K. Goulianos26 CAL Calibration overlap events signal region cal distribution for slice of RPS / mean ~ 30%
Low x 2006, Lisbon, Portugal, June 28 – July 2Results from CDF on Diffraction K. Goulianos27 Dijet Properties SD boosted opposite to pbar p p jet
Low x 2006, Lisbon, Portugal, June 28 – July 2Results from CDF on Diffraction K. Goulianos28 Alignment of RPS using Data maximize the |t|-slope determine X and Y offsets
Low x 2006, Lisbon, Portugal, June 28 – July 2Results from CDF on Diffraction K. Goulianos29 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 similarly to proton!
Low x 2006, Lisbon, Portugal, June 28 – July 2Results from CDF on Diffraction K. Goulianos30 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 < 10,000 GeV 2 across soft and hard diffraction!
Low x 2006, Lisbon, Portugal, June 28 – July 2Results from CDF on Diffraction K. Goulianos31 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
Low x 2006, Lisbon, Portugal, June 28 – July 2Results from CDF on Diffraction K. Goulianos32 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 soon for results! Exclusive Based on 3 events observed: Good agreement with KMR: DIJETSDIJETS
Low x 2006, Lisbon, Portugal, June 28 – July 2Results from CDF on Diffraction K. Goulianos33 Dijets: Data vs MC Excess of events at high R jj is well described by both exclusive dijet production models Currently investigating the dependence of the cross section on second jet E T to differentiate between the two models ExHuME (KMR): gg gg process uses LO pQCD Exclusive DPE (DPEMC) non-pQCD based on Regge theory
Low x 2006, Lisbon, Portugal, June 28 – July 2Results from CDF on Diffraction K. Goulianos34 Exclusive Dijet Signal COMPARISON inclusive data vs b/c-jet data vs inclusive
Low x 2006, Lisbon, Portugal, June 28 – July 2Results from CDF on Diffraction K. Goulianos35 Exclusive ee Search (anti)proton not detected require 2 EM showers (E T >5 GeV, |h|<2 ) veto on all BSCs and all calorimetery except for the 2 EM showers L~530 pb -1 delivered L effective =46 pb -1 19 events with 2 EM showers + ”nothing” [above threshold] QED process: cross-check to exclusive
Low x 2006, Lisbon, Portugal, June 28 – July 2Results from CDF on Diffraction K. Goulianos36 16 candidate events found background: Exclusive ee Search control sample for search good agreement with LPAIR : E T 1 =6.1 GeV E T 2 =6.0 GeV
Low x 2006, Lisbon, Portugal, June 28 – July 2Results from CDF on Diffraction K. Goulianos37 Exclusive Search 3 candidate events found background: good agreement with KMR: E T 1 =6.8 GeV/c E T 2 =5.9 GeV/c H ~ 10 fb (if H exists) within a factor ~ 2-3, higher in MSSM
Low x 2006, Lisbon, Portugal, June 28 – July 2Results from CDF on Diffraction K. Goulianos38 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 ?
Low x 2006, Lisbon, Portugal, June 28 – July 2Results from CDF on Diffraction K. Goulianos39 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 High mass ( 4 TeV !) and multi-gap diffraction Exclusive production Reduced bgnd for std Higgs to study properties Discovery channel for certain Higgs scenarios
Low x 2006, Lisbon, Portugal, June 28 – July 2Results from CDF on Diffraction K. Goulianos40 BACKUP
Low x 2006, Lisbon, Portugal, June 28 – July 2Results from CDF on Diffraction K. Goulianos41 Diffractive DIS: two models e Q2Q2 ** p jet reorganize probing the proton structure! e ** t p IP Particle-like PomeronColor reorganization what is the Pomeron structure?
Low x 2006, Lisbon, Portugal, June 28 – July 2Results from CDF on Diffraction K. Goulianos42 Inclusive vs Diffractive DIS P (0)-1 ( q )/2 F 2 ~ x qq KG, “Diffraction: a New Approach,” J.Phys.G26: ,2000 e-Print Archive: hep-ph/ Inclusive DIS Inclusive & diffr. DIS
Low x 2006, Lisbon, Portugal, June 28 – July 2Results from CDF on Diffraction K. Goulianos43 DSF: H1 vs ZEUS CDF H1 Using preliminary pdf’s from Fit including charm data Fit without charm data ZEUS H1 M. Arneodo, HERA/LHC workshop, CERN, Oct 2004 Flat after subtracting Reggeon contribution
Low x 2006, Lisbon, Portugal, June 28 – July 2Results from CDF on Diffraction K. Goulianos44 Diffractive Tevatron p jet reorganize jet g ~ 0.2 Agreement with data!
Low x 2006, Lisbon, Portugal, June 28 – July 2Results from CDF on Diffraction K. Goulianos45 -dependence: Inclusive vs Dijet Pomeron dominated
Low x 2006, Lisbon, Portugal, June 28 – July 2Results from CDF on Diffraction K. Goulianos46 Gap Between Jets Question
Low x 2006, Lisbon, Portugal, June 28 – July 2Results from CDF on Diffraction K. Goulianos47 valence quarks antiproton x=x= Diffraction from the Deep Sea proton g =0.20 q =0. 04 R =-0.5 g =0.5 q =0.3 SOFTHARD deep sea Derive diffractive from inclusive PDFs and color factors antiproton valence quarks