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Diffraction at CDF and Universality of Diffractive Factorization Breaking Konstantin Goulianos The Rockefeller University http://physics.rockefeller.edu/dino/my.html / Low x 2010, 23-27 June 2010 Kavala (Greece) PhillippiThassos
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CONTENTS Introduction Diffraction at CDF: latest results Dijets W and Z Jet-Gap-Jet Universality of Diffractive Factorization Breaking
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K. Goulianos low-x 27-29 June 2010 KavalaDiffraction at CDF and Universality of DFB 3 INTERACTIONS Diffractive: Colorless exchange carrying vacuum quantum numbers Non-diffractive: Color-exchange POMERONPOMERON Goal: understand the QCD nature of the diffractive exchange rapidity gap Incident hadrons acquire color and break apart CONFINEMENT Incident hadrons retain their quantum numbers remaining colorless pseudo- DECONFINEMENT
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K. Goulianos low-x 27-29 June 2010 KavalaDiffraction at CDF and Universality of DFB 4 Definitions dN/d M p p’ rap-gap =-ln 0 p M ,t,t p p p’ ln M 2 ln s particles M 2 scaling: no price paid for increasing diffractive gap size
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K. Goulianos low-x 27-29 June 2010 KavalaDiffraction at CDF and Universality of DFB 5 Diffractive pp(pp) processes @ CDF Single Diffraction dissociation (SD) Double Diffraction dissociation (DD) Double Pomeron Exchange (DPE) Central Diffraction Single + Double Diffraction (SDD) SD SDD Elastic scatteringTotal cross section T =Im f el (t=0) OPTICAL THEOREM gap nested gap use gap nesting until no diffractive gap fits in √s'
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K. Goulianos low-x 27-29 June 2010 KavalaDiffraction at CDF and Universality of DFB 6 M 2 scaling KG&JM, PRD 59 (1999) 114017 factorization breaks down to ensure M 2 scaling - why? Regge 1 Independent of s over 6 orders of magnitude in M 2 ! d dM 2 | t=-0.05 independent of s over 6 orders of magnitude ! data
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K. Goulianos low-x 27-29 June 2010 KavalaDiffraction at CDF and Universality of DFB 7 T SD (pp & pp) Factor of ~8 (~5) suppression at √s = 1800 (540) GeV suppressed relative to Regge KG, PLB 358, 379 (1995) 1800 GeV 540 GeV M ,t,t p p p’ T SD mb √s=22 GeV
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K. Goulianos low-x 27-29 June 2010 KavalaDiffraction at CDF and Universality of DFB 8 REMARKS MC generators for diffractive studies: PYTHIA & PHOJET disagree with each other and with data. Diffractive factorization breaking at HERA: Vector mesons: vs. W, b-slopes of t-distributions, … Dijets: E T jet dependence, resolved vs. direct components,... Renormalization (RENORM) model: describes both p ( p ) - p and – p MC based on RENORM model: MBR (Minimum Bias Rockefeller) used at CDF. Luminosity measurement: requires a known x-section and MC predicted acceptance of a detector component. suggest SD: well defined and slowly varying x-section
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K. Goulianos low-x 27-29 June 2010 KavalaDiffraction at CDF and Universality of DFB 9 The CDF II Detector
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K. Goulianos low-x 27-29 June 2010 KavalaDiffraction at CDF and Universality of DFB 10 Diffractive Structure Function breakdown of QCD factorization !
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K. Goulianos low-x 27-29 June 2010 KavalaDiffraction at CDF and Universality of DFB 11 Diffractive Structure Function CDF H1 momentum fraction of parton in “Pomeron” – note quotes Using preliminary PDF’s from same suppression as in soft diffraction – why?
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K. Goulianos low-x 27-29 June 2010 KavalaDiffraction at CDF and Universality of DFB 12 Dijet E T distributions similar for SD and ND over 4 orders of magnitude Kinematics
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K. Goulianos low-x 27-29 June 2010 KavalaDiffraction at CDF and Universality of DFB 13 DSF from Dijets in Run II )(xF ) F Bj ND jj Bj SD jj )(xRate )(xRate )R(x Bj ND jj Bj SD jj Bj t - distribution The x Bj -distribution of the SD/ND ratio has no strong Q 2 dependence the slope of the t-distribution is independent of Q 2 the t-distribution displays a diffraction minimum at |t| ~ 2.5 (GeV/c) 2 (?) all three results “ first observation ” ?????? x Bj - distribution CDF Run II Preliminary b - slope of t-distribution ?
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K. Goulianos low-x 27-29 June 2010 KavalaDiffraction at CDF and Universality of DFB 14 Pomeron dominated & dependence of F D jj – Run I
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K. Goulianos low-x 27-29 June 2010 KavalaDiffraction at CDF and Universality of DFB 15 Diffractive W / Z - analysis CDF Run II Preliminary
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K. Goulianos low-x 27-29 June 2010 KavalaDiffraction at CDF and Universality of DFB 16 Diffractive W / Z - results CDF Run II Preliminary
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K. Goulianos low-x 27-29 June 2010 KavalaDiffraction at CDF and Universality of DFB 17 CENTRAL GAPS Jet gap
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K. Goulianos low-x 27-29 June 2010 KavalaDiffraction at CDF and Universality of DFB 18 DIFFRACTION PHENOMENOLOGY
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K. Goulianos low-x 27-29 June 2010 KavalaDiffraction at CDF and Universality of DFB 19 Gap probability MUST be normalized to unity! Single Diffraction 2 independent variables: t color factor gap probability sub-energy x-section
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K. Goulianos low-x 27-29 June 2010 KavalaDiffraction at CDF and Universality of DFB 20 Single diffraction (re)normalized Pumplin bound obeyed at all impact parameters Grows slower than s
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K. Goulianos low-x 27-29 June 2010 KavalaDiffraction at CDF and Universality of DFB 21 Unitarity and Renormalization Two free parameters: s 0 and g PPP Obtain product g PPP s 0 from SD Renormalized Pomeron flux determines s 0 Get unique solution for g PPP Pomeron-proton x-section Pomeron flux gap probability Set to unity – determines g PPP and s 0 KG, PLB 358 (1995) 379
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K. Goulianos low-x 27-29 June 2010 KavalaDiffraction at CDF and Universality of DFB 22 Dijets in p at HERA from RENORM Factor of ~3 suppression expected at W~200 GeV (just as in pp collisions) for both direct and resolved components K. Goulianos, POS (DIFF2006) 055 (p. 8)
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K. Goulianos low-x 27-29 June 2010 KavalaDiffraction at CDF and Universality of DFB 23 Multi-gap Diffraction (KG, hep-ph/0205141) y
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K. Goulianos low-x 27-29 June 2010 KavalaDiffraction at CDF and Universality of DFB 24 Multi-gap Cross Sections Same suppression as for single gap! Gap probabilitySub-energy cross section (for regions with particles) 5 independent variables color factor
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K. Goulianos low-x 27-29 June 2010 KavalaDiffraction at CDF and Universality of DFB 25 Rapidity Gaps in Fireworks
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K. Goulianos low-x 27-29 June 2010 KavalaDiffraction at CDF and Universality of DFB 26 “Gap survival probability” S =
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K. Goulianos low-x 27-29 June 2010 KavalaDiffraction at CDF and Universality of DFB 27 Hard Diffraction Phenomenology
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K. Goulianos low-x 27-29 June 2010 KavalaDiffraction at CDF and Universality of DFB 28 Diffractive dijets @ Tevatron p jet reorganize jet
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K. Goulianos low-x 27-29 June 2010 KavalaDiffraction at CDF and Universality of DFB 29 F D JJ ( , Q 2 ) @ Tevatron
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K. Goulianos low-x 27-29 June 2010 KavalaDiffraction at CDF and Universality of DFB 30 SD/ND dijet ratio vs. x Bj @ CDF 0.035 < < 0.095 Flat dependence for < 0.5 CDF Run I
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K. Goulianos low-x 27-29 June 2010 KavalaDiffraction at CDF and Universality of DFB 31 Diffractive DIS @ HERA e Q2Q2 ** p jet reorganize J. Collins: factorization holds (but under what conditions?) e ** t p IP Pomeron exchangeColor reorganization Results favor color reorganization
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K. Goulianos low-x 27-29 June 2010 KavalaDiffraction at CDF and Universality of DFB 32 Dijets in p at HERA - 2008 DIS 2008 talk by W. Slomiński, ZEUS 20-50 % apparent rise when E T jet 5 10 GeV due to suppression at low E T jet !!!
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K. Goulianos low-x 27-29 June 2010 KavalaDiffraction at CDF and Universality of DFB 33 Vector meson production (Pierre Marage, HERA-LHC 2008) left - why different vs. W slopes? more room for particles right - why smaller b-slope in *p? same reason
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K. Goulianos low-x 27-29 June 2010 KavalaDiffraction at CDF and Universality of DFB 34 Unexpected, not understood QCD factorisation not OK Dijets in p at HERA – 2007 Hadron-like e Q2Q2 ** p jet reorganize Direct vs. resolved the reorganization diagram predicts: suppression at low Z | P jets, since larger is available for particles same suppression for direct and resolved processes
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K. Goulianos low-x 27-29 June 2010 KavalaDiffraction at CDF and Universality of DFB 35 Pomeron ' and t in a QCD inspired parton model approach
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K. Goulianos low-x 27-29 June 2010 KavalaDiffraction at CDF and Universality of DFB 36 SD and ratio of '
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K. Goulianos low-x 27-29 June 2010 KavalaDiffraction at CDF and Universality of DFB 37 The total x-section √s F =22 GeV SUPERBALL MODEL
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K. Goulianos low-x 27-29 June 2010 KavalaDiffraction at CDF and Universality of DFB 38 Monte Carlo Strategy for the LHC T from SUPERBALL model optical theorem Im f el ( t=0 ) dispersion relations Re f el ( t=0 ) differential SD from RENORM use nested pp final states for pp collisions at the IP p sub-energy √s‘ See K. Goulianos, Phys. Lett. B 193 (1987) 151 pp “A new statistical description of hardonic and e+e− multiplicity distributions “ T optical theorem Im f el (t=0) dispersion relations Re f el (t=0) MONTE CARLO STRATEGY CONCUSION stay tuned …
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K. Goulianos low-x 27-29 June 2010 KavalaDiffraction at CDF and Universality of DFB 39 The first CMS event
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