Low x 2008, Kolymbari-Crete, GreeceDiffractive and Exclusive JJ and W/Z at CDF K. Goulianos1 Diffractive and Exclusive Production of Dijets and W/Z at CDF K. Goulianos The Rockefeller University and the CDF collaboration

Low x 2008, Kolymbari-Crete, GreeceDiffractive and Exclusive JJ and W/Z at CDF K. Goulianos2 A bit of history … Diffraction in the70s  the Pomeron unveiled! Opening night at Chez Leon - Fermilab (1989) (right)  Greg Snow on violin (Ph.D thesis: first observation of diffractive  dissociation)

Low x 2008, Kolymbari-Crete, GreeceDiffractive and Exclusive JJ and W/Z at CDF K. Goulianos3 At the Gorge of Samaria (1980) w /R. Feynman – a day of jokes!

Low x 2008, Kolymbari-Crete, GreeceDiffractive and Exclusive JJ and W/Z at CDF K. Goulianos4 Contents  Introduction  Dijets  W/Z

Low x 2008, Kolymbari-Crete, GreeceDiffractive and Exclusive JJ and W/Z at CDF K. Goulianos5 Introduction SD DDDPESDD=SD+DD p p JJ, ee,  Soft and hard CDF JJ, b, J/   W exclusive

Low x 2008, Kolymbari-Crete, GreeceDiffractive and Exclusive JJ and W/Z at CDF K. Goulianos6 SD kinematics MXMX ,t,t  dN/d  p MXMX p p’ rap-gap  =-ln  0

Low x 2008, Kolymbari-Crete, GreeceDiffractive and Exclusive JJ and W/Z at CDF K. Goulianos7 Breakdown of factorization – Run I ~8 ZEUS and H1 vs. CDF H1 ZEUS CDF KG, PLB 358 (1995) 379  T sd ~ 8 soft ** e p p p p p hard Magnitude: same suppression factor in soft and hard diffraction! Shape of  distribution: ZEUS, H1, and Tevatron – why different shapes?

Low x 2008, Kolymbari-Crete, GreeceDiffractive and Exclusive JJ and W/Z at CDF K. Goulianos8 All fractions ~ 1% (differences due to kinematics)  ~ uniform suppression  ~ FACTORIZATION ! Hard diffractive fractions – Run I  dN/d  / J/  /- 0.25b /- 0.55W /- 0.10JJ Fraction % Fraction: SD/ND 1800 GeV FACTORIZATION !

Low x 2008, Kolymbari-Crete, GreeceDiffractive and Exclusive JJ and W/Z at CDF K. Goulianos9 Multi-gap diffraction – Run I  restoring 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 w /preliminary pdf’s from

Low x 2008, Kolymbari-Crete, GreeceDiffractive and Exclusive JJ and W/Z at CDF K. Goulianos10 Pomeron dominated  &  dependence of F D jj – Run I

Low x 2008, Kolymbari-Crete, GreeceDiffractive and Exclusive JJ and W/Z at CDF K. Goulianos11 Diffractive structure function – Run II Q 2 - dependence E T jet ~ 100 GeV !  Small Q2 dependence in region 100<Q 2 < GeV2 where each d  ND /dE T d  ND /dE T vary by a factor of ~10 4  The Pomeron evolves as the proton !

Low x 2008, Kolymbari-Crete, GreeceDiffractive and Exclusive JJ and W/Z at CDF K. Goulianos12 Diffractive structure function – Run II 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 < ~ GeV 2 across soft and hard diffraction!

Low x 2008, Kolymbari-Crete, GreeceDiffractive and Exclusive JJ and W/Z at CDF K. Goulianos13 Looks like… … the underlying diffractive PDF on a hard scale is similar to the proton PDF except for small differences - presumably due to the requirement of combining with the soft PDF to form a spin 1 color singlet with vacuum quantum numbers.

Low x 2008, Kolymbari-Crete, GreeceDiffractive and Exclusive JJ and W/Z at CDF K. Goulianos14 Diffractive W/Z production W, Z p p p IP W, Z p p p IP  Diffractive W production probes the quark content of the Pomeron –To leading order, the W is produced by a quark in the Pomeron  Production by gluons is suppressed by a factor of  S, and can be distinguished from quark production by an associated jet

Low x 2008, Kolymbari-Crete, GreeceDiffractive and Exclusive JJ and W/Z at CDF K. Goulianos15 Diffractive W/Z - motivation In Run I, by combining diffractive dijet production with diffractive W production we determined the quark/gluon content of the Pomeron ===  In Run II we aim at determining the diffractive structure function for a more direct comparison with HERA. To accomplish this we use:  New forward detectors  New methodology  More data Phys Rev Lett 78, 2698 (1997) Fraction of W events due to SD R w =[1.15±0.51(stat)±0.20(syst) ]% for  <0.1 integrated over t JJ

Low x 2008, Kolymbari-Crete, GreeceDiffractive and Exclusive JJ and W/Z at CDF K. Goulianos16 The DF II detectors RPS acceptance ~80% for 0.03 < x < 0.1 and |t| < 0.1

Low x 2008, Kolymbari-Crete, GreeceDiffractive and Exclusive JJ and W/Z at CDF K. Goulianos17 The CDF

Low x 2008, Kolymbari-Crete, GreeceDiffractive and Exclusive JJ and W/Z at CDF K. Goulianos18 Using RPS information:  No background from gaps due to multiplicity fluctuations  No gap survival probability systematics  The RPS provides accurate event-by-event  measurement  Determine the full kinematics of diffractive W production by obtaining   using the equation: where This allows the determination of:  W mass  x Bj  Diffractive structure function Diffractive W/Z analysis

Low x 2008, Kolymbari-Crete, GreeceDiffractive and Exclusive JJ and W/Z at CDF K. Goulianos19 W/Z selection requirements Standard W/Z selection Diffractive W/Z selection  RPS trigger counters - MIP  RPS track <  <0.10, |t|<1  W  50 < M W (  RPS,  cal ) < 120  Z   cal < 0.1

Low x 2008, Kolymbari-Crete, GreeceDiffractive and Exclusive JJ and W/Z at CDF K. Goulianos20 Reconstructed diffractive W mass

Low x 2008, Kolymbari-Crete, GreeceDiffractive and Exclusive JJ and W/Z at CDF K. Goulianos21 Rejection of multiple interaction events ND dijet w /soft SD overlap ND dijet w /soft SD overlap

Low x 2008, Kolymbari-Crete, GreeceDiffractive and Exclusive JJ and W/Z at CDF K. Goulianos22 Diffractive W/Z results R W (0.03 <  < 0.10, |t|<1)= [0.97 ± 0.05(stat) ± 0.11(syst)]% Run I: R W =1.15±0.55 % for  <0.1  estimate 0.97±0.47 % in 0.03 <  < 0.10 & |t|<1) R Z (0.03 < x < 0.10, |t|<1)= [0.85 ± 0.20(stat) ± 0.11(syst)]% DØ Phys Lett B 574, 169 (2003) R w =[5.1±0.51(stat)±0.20(syst)]% gap acceptance A gap =(0.21±4)% uncorrected for A gap  R W =[ ]% R Z =[ ]% Stay connected tor results on F D W/Z CDF PRL 78, 2698 (1997) R w =[1.15±0.51(stat)±0.20(syst)]%g ap acceptance A gap =0.81 uncorrected for A gap  R w =(0.93±0.44)% (A gap calculated from MC) CDF/DØ Comparison – Run I (  < 0.1)

EXCLUSIVE JJ & HIGGS BOSONS   M~(1-2) GeV Determine spin of H gap -jet  p p H

Low x 2008, Kolymbari-Crete, GreeceDiffractive and Exclusive JJ and W/Z at CDF K. Goulianos24 Exclusive dijet and Higg production H DPEMC ExHuME URL: DOI: /PhysRevD http://link.aps.org/abstract/PRD/v77/e052004

Low x 2008, Kolymbari-Crete, GreeceDiffractive and Exclusive JJ and W/Z at CDF K. Goulianos25 The DPE data sample

Low x 2008, Kolymbari-Crete, GreeceDiffractive and Exclusive JJ and W/Z at CDF K. Goulianos26 Kinematic distributions

Low x 2008, Kolymbari-Crete, GreeceDiffractive and Exclusive JJ and W/Z at CDF K. Goulianos27 Exclusive dijet signal dijet mass fraction – all jets Exclusive b-jets are suppressed as expected (J Z = 0 selection rule) Excess observed over POMWIG MC prediction at large Rjj b-jet dijet mass fraction

Low x 2008, Kolymbari-Crete, GreeceDiffractive and Exclusive JJ and W/Z at CDF K. Goulianos28 Underlying event

Low x 2008, Kolymbari-Crete, GreeceDiffractive and Exclusive JJ and W/Z at CDF K. Goulianos29 Jet1 vs. Jet2: signal and background regions DATA POMWIG A: signal region B: background region

Low x 2008, Kolymbari-Crete, GreeceDiffractive and Exclusive JJ and W/Z at CDF K. Goulianos30 Background region

Low x 2008, Kolymbari-Crete, GreeceDiffractive and Exclusive JJ and W/Z at CDF K. Goulianos31 Inclusive DPE W /LRG-p data vs. MC Shape of excess of events at high R jj is well described by both ExHuME & DPEMC ExHuME (KMR): gg  gg process (based on LO pQCD) DPEMC: exclusive DPE MC based on Regge theory Rjj ExHuME DPEMC  exclusive MC models 

Low x 2008, Kolymbari-Crete, GreeceDiffractive and Exclusive JJ and W/Z at CDF K. Goulianos32 HF suppression vs. inclusive signal HF suppression Invert HF vertically and compare with 1-MC/DATA  good agreement observed HF vs. incl

Low x 2008, Kolymbari-Crete, GreeceDiffractive and Exclusive JJ and W/Z at CDF K. Goulianos33 ExHuME vs. DPEMC and vs. data  Measured x-sections favor ExHuME  KMR x 1/3 agrees with data  Within theoretical uncertainty of +/- factor of 3   jj excl /  incl approx. independent of E T min  WHY?

Low x 2008, Kolymbari-Crete, GreeceDiffractive and Exclusive JJ and W/Z at CDF K. Goulianos34 Exclusive dijet x-section vs. M jj curve : ExHuME hadron-level exclusive dijet cross sections vs. dijet mass points: derived from CDF excl. dijet x-sections using ExHuME Stat. and syst. errors are propagated from measured cross section uncertainties using M jj distribution shapes of ExHuME generated data.

SUMMARY HIGGS ?  Introduction  diffractive PDF looks like proton PDF  Diffractive W/Z – RPS data  W diffractive fraction in agreement with Run I  W/Z diffractive fractions equal within error  New techniques developed to enable extracting the diffractive structure function in W production  Exclusive dijet/(Higgs?) production  Results favor ExHuME over DPEMC Phys. Rev. D 77, (2008) DIJET W/Z

Low x 2008, Kolymbari-Crete, GreeceDiffractive and Exclusive JJ and W/Z at CDF K. Goulianos36 BACKUP Measurements with the MiniPlugs Dynamic alignment of RPS detectors E T jet calibration

Low x 2008, Kolymbari-Crete, GreeceDiffractive and Exclusive JJ and W/Z at CDF K. Goulianos37 Measurements w / the MiniPlugs ADC counts in MiniPlug towers in a pbar-p event at 1960 GeV. “jet” indicates an energy cluster and may be just a hadron counts ~ 1 GeV Multiplicity of SD and ND events ENERGY MP TOWER STRUCTURE POSITION NIM A 430 (1999) NIM A 496 (2003) NIM A 518 (2004)

Low x 2008, Kolymbari-Crete, GreeceDiffractive and Exclusive JJ and W/Z at CDF K. Goulianos38 Dynamic Alignment of RPS Detectors Method: iteratively adjust the RPS X and Y offsets from the nominal beam axis until a maximum in the b-slope is t=0. Limiting factors 1-statistics 2-beam size 3-beam CDF W /lowlum data

Low x 2008, Kolymbari-Crete, GreeceDiffractive and Exclusive JJ and W/Z at CDF K. Goulianos39 E T jet Calibration Calibrate E t jet or , as you wish!  use RPS information to check jet energy corrections 

Low x 2008, Kolymbari-Crete, GreeceDiffractive and Exclusive JJ and W/Z at CDF K. Goulianos40 thank you