1. CDF RESULTS ON DIFFRACTION AND EXCLUSIVE PRODUCTION
Konstantin Goulianos
14th Workshop on Elastic and Diffractive Scattering (EDS Blois Workshop)
Frontiers of QCD:  From Puzzles to Discoveries
December 15-21, 2011, Qui Nhon, Vietnam

2. CDF Diffraction and Exclusive Production
CONTENTS
INTRODUCTION
DIFFRACTION
Diffractive W and Z production – published
Diffractive structure function in dijet production – update
Rapidity gaps between jets - update
EXCLUSIVE PRODUCTION
Exclusive gg in pp collisions at 1.96 TeV – new!
CONCLUSION
EDS-2011 Vietnam
CDF Diffraction and Exclusive Production

3. Diffraction at CDF in Run I
Find PRL/PRD references in
sT=Im fel (t=0)
Elastic scattering
Total cross section
gap
OPTICAL
THEOREM f f h h
SDD SD DD
DPE /CD
Single Diffraction or
Single Dissociation
Double Diffraction or Double Dissociation
Double Pom. Exchange or
Central Dissociation
Single + Double
Diffraction (SDD)
multi-gap w/ two gaps
 part of SD
EDS-2011 Vietnam
CDF Diffraction and Exclusive Production

4. CDF Diffraction and Exclusive Production
Definitions p’ M
x,t p p’ p p M p’
dN/dh
gap
particles
Dh=-lnx
Dh=-lnx h
ln M2
ln s
No radiation  no price paid for increasing diffractive gap size
EDS-2011 Vietnam
CDF Diffraction and Exclusive Production

5. Highlights of Run I Results
The MBR (Minimum Bias Rockefeller) Monte Carlo was used in the forward physics program - see:
EDS-2011 Vietnam
CDF Diffraction and Exclusive Production

6. CDF Diffraction and Exclusive Production
TOTAL SD x-SECTION
Run I M
x,t p p’
 suppressed relative to Regge
KG, PLB 358, 379 (1995)
1800 GeV
540 GeV
Regge
Factor of ~8 (~5)
suppression at
√s = 1800 (540) GeV
 RENORMALIZATION
 CDF results
√s=22 GeV
EDS-2011 Vietnam
CDF Diffraction and Exclusive Production

7. CDF Diffraction and Exclusive Production
DD at CDF
Run I
gap probability
x-section
renormalized
EDS-2011 Vietnam
CDF Diffraction and Exclusive Production

8. CDF Diffraction and Exclusive Production
SDD at CDF
Run I
Excellent agreement between data and MBR (MinBiasRockefeller) MC
EDS-2011 Vietnam
CDF Diffraction and Exclusive Production

9. CDF Diffraction and Exclusive Production
DPE / CD at CDF
Run I
Excellent agreement between data and MBR
 low and high masses are correctly implemented
EDS-2011 Vietnam
CDF Diffraction and Exclusive Production

10. CDF Diffraction and Exclusive Production
Hard diffraction
Run I
Fraction:
SD/ND ratio
@ 1800 GeV
Fraction % JJ
0.75 +/- 0.10 W
1.15 +/- 0.55 b
0.62 +/- 0.25
hard
dN/dh
J/y
1.45 +/- 0.25
All fractions ~ 1%
(differences due to kinematics)
~ FACTORIZATION !
FACTORIZATION ! h
EDS-2011 Vietnam
CDF Diffraction and Exclusive Production

11. Diffrr. Structure Function - DSF
Run I
 breakdown of QCD factorization
Run I
PRL 84, 5043 (2000)
p+pp+[JJ+X] _
suppression factor is 2.5 times larger than in soft diffraction
one of the main reasons for repeating measurement in Run II with an improved forward detector system
~ 20
b  momentum fraction of parton in “Pomeron”
EDS-2011 Vietnam
CDF Diffraction and Exclusive Production

12. CDF Diffraction and Exclusive Production
Puzzles from run I
Run I
gap fractions are suppressed relative to theory predictions, both for soft (Regge) and hard diffraction
…but
factorization holds among processes at the same energy, just like at HERA
DSF at √s=1800 GeV suppressed by factor ~ 20 while Regge by factor ~8  contradicts RENORM prediction,
but…see further down in the talk
EDS-2011 Vietnam
CDF Diffraction and Exclusive Production

13. The CDF II Detector – plan view
EDS-2011 Vietnam
CDF Diffraction and Exclusive Production

14. CDF Diffraction and Exclusive Production
The CDF
3.5<|h|<5.1
EDS-2011 Vietnam
CDF Diffraction and Exclusive Production

15. Measurements w/the MiniPlugs
MP TOWER
STRUCTURE
MULTIPLICITY
@ POSITION
ENERGY
ADC counts in MiniPlug towers
in a pbar-p event at 1960 GeV.
“jet” indicates an energy cluster
and may be just a hadron.
1000 counts ~ 1 GeV
NIM A 430 (1999)
NIM A 496 (2003)
NIM A 518 (2004)
Multiplicity of SD and ND events
EDS-2011 Vietnam
CDF Diffraction and Exclusive Production

16. CDF Diffraction and Exclusive Production
Diffractive W/Z
In LO QCD W probes the quark content of diffractive exchange.
Production by gluons is suppressed by a factor of aS and distinguished by an associated jet. MW
EDS-2011 Vietnam
CDF Diffraction and Exclusive Production

17. MW from inclusive We/m+v
Method: compare transverse MW data with MC
MWdiff= 80.9± 0.7(GeV/c2)
EDS-2011 Vietnam
CDF Diffraction and Exclusive Production

18. Data and event selection
0.6 fb-1 of integrated luminosity data W Z
EDS-2011 Vietnam
CDF Diffraction and Exclusive Production

19. Diffractive W/Z fractions
~80%
~87%%
68-80%
f1-int =(25.6±1.2)%
Run I: RW =1.15±0.55 % for xmin< x <0.1
 [0.88±0.21 (stat)% within 0.03 < x < 0.10 & |t|<1
EDS-2011 Vietnam
CDF Diffraction and Exclusive Production

20. DSF from Dijets in Run II) (x F Bj ND jj SD
Rate
R(x Þ
xBj-distribution of SD/ND ratio has no strong Q2 dependence
slope of t-distribution is independent of Q2 for |t| < 1 (GeV/c)2
does the t-distribution have a diffraction minimum beyond |t|=1 GeV/c)2??
 stay tuned, release coming soon!
EDS-2011 Vietnam
CDF Diffraction and Exclusive Production

21. Dijet ET distributions
 similar for SD and ND over 4 orders of magnitude
Kinematics
EDS-2011 Vietnam
CDF Diffraction and Exclusive Production

22. Q2 dependence of DSF in dijets
ETjet ~ 100 GeV !
Small Q2 dependence in region 100<Q2< GeV2 where dsSD/dET & dsND/dET vary by a factor of ~104 !
 The Pomeron evolves as the proton !
EDS-2011 Vietnam
CDF Diffraction and Exclusive Production

23. Diffractive structure function – Run II t - dependence
Fit ds/dt to a double exponential:
No diffraction dips at |t| < 1 GeV2
No Q2 dependence in slope
from inclusive up to Q2~104 GeV2
Same slope over entire region of
0 < Q2 < ~ GeV2!
EDS-2011 Vietnam
CDF Diffraction and Exclusive Production

24. CDF Diffraction and Exclusive Production
sTSD and dijets p e g* p
soft
dijet p p p ~8
ZEUS and H1 vs. CDF H1
ZEUS
CDF
KG, PLB 358 (1995) 379
sTsd
~ 8 b
Magnitude: same suppression factor in soft and hard diffraction!
Shape of b distribution: ZEUS, H1, and Tevatron – why different slapes?
EDS-2011 Vietnam
CDF Diffraction and Exclusive Production

25. CDF Diffraction and Exclusive Production
GAPS BETWEEN JETS
Jet
gap
analysis nears completion
repeat at LHC at 7 TeV with higher ET forward jets
EDS-2011 Vietnam
CDF Diffraction and Exclusive Production

26. EXCLUSIVE Dijet Excl. Higgs THEORY CALIBRATIONp _ }
JJ gg cc
PRD 77, (2008)
PRL 99, (2007)
PRL (2007)
Exclusive dijets
EDS-2011 Vietnam
CDF Diffraction and Exclusive Production

27. Exclusive gg production
Phys.Rev.Lett. 99, (2007)
ET > 5 GeV
||< 1.0
3 gg / popo evts observed
2  candidates
1 00 candidate
V.A.Khoze et al. Eur. Phys. J C38, 475 (2005):
2 events   ~ 90 fb, in agreement with theory
cannot claim discovery as bgd study was made a posteriori
EDS-2011 Vietnam
CDF Diffraction and Exclusive Production

28. Exclusive Dimuon Production
p+p→p++-+p
3 GeV/c2 <M<4 GeV/c2
many physics processes
in this data set:
 c
exclusive c in DPE
EDS-2011 Vietnam
CDF Diffraction and Exclusive Production

29. CDF Diffraction and Exclusive Production
Exclusive J/ and (2s)
J/ production
243 21 events
d/dy|y=0= 3.92 ± 0.62 nb
Theoretical Predictions
2.8 nb [Szczurek07,],
2.7 nb [Klein&Nystrand04],
3.0 nb [Conclaves&Machado05], and
3.4 nb [Motkya&Watt08].
Y(2s) production
347 events
d/dy|y=0 = ± 0.15 nb
R = (2s)/J/= 0.14 ± 0.05
In agreement with HERA: R = ± in a similar kinematic region
PRL (2009)
J/
Fit :
2 Gaussians + QED continuum
(2s)
QED continuum
EDS-2011 Vietnam
CDF Diffraction and Exclusive Production

30. Exclusive c→J/(→+-)+
PRL (2009)
Allowing EM towers (ET >80MeV)
large increase in the J/y peak & minor change in the y(2s) peak
 Evidence for:
c→J/+ production
J/y 286 352 = +66 events
Y(2s) 3940 = +1 event
Allow extra EM tower
d/dy|y=0 = 75 ± 14 nb,
compatible with theoretical predictions
160 nb (Yuan 01)
90 nb (KMR01)
EDS-2011 Vietnam
CDF Diffraction and Exclusive Production

31. Exclusive gg production - new!
(submitted to PRL: arXiv: )
EDS-2011 Vietnam
CDF Diffraction and Exclusive Production

32. Exclusive gg and e+e- events
EDS-2011 Vietnam
CDF Diffraction and Exclusive Production

33. CDF Diffraction and Exclusive Production
Exclusive gg data vs. MC
EDS-2011 Vietnam
CDF Diffraction and Exclusive Production

34. Exclusive gg cross section
EDS-2011 Vietnam
CDF Diffraction and Exclusive Production

35. Exclusive gg event candidate
EDS-2011 Vietnam
CDF Diffraction and Exclusive Production

36. Tevatron Low-s Energy Scan September 8-16 2011
√s=300 & 900 GeV (CDF already studied √s=630 , 1800 &1960 GeV)
MinBias events (charged particle multiplicities, dN/dh, etc…
Underlying event for various processes
Gap-X-Gap events
Tune MC generators
Plan to have (some) results in summer conferences
CDF data
EDS-2011 Vietnam
CDF Diffraction and Exclusive Production

37. CDF Diffraction and Exclusive Production
SUMMARY
Diffractive W and Z fractions: final results based on Run II CDF data using a Roman Pot Spectrometer (RPS) to measure the recoil pbar momentum
The W fraction is in good agreement with the fraction measured in Run I based on a rapidity gap analysis
The Z fraction is about 10% smaller than the W fraction, just as in non-diffractive events
Diffractive structure function in dijet production:
no strong Q2 and/or t dependence over a wide range
is there a diffraction dip in the t-distribution?  coming soon
Central rapidity gaps in min-bias and very forward dijet events:
same dependence on Dh=hmax- hmin
Exclusive production observed/measured for several processes
thank you for your attendance
EDS-2011 Vietnam
CDF Diffraction and Exclusive Production

38. CDF Diffraction and Exclusive Production
BACKUP
EDS-2011 Vietnam
CDF Diffraction and Exclusive Production

39. DIFFRACTIVE AND NON-DIFFRACTIVE INTERACTIONS
Non-diffractive  no “large” gaps
Color-exchange
Diffractive  gaps
Colorless exchange with vacuum quantum numbers
Incident hadrons acquire color
and break apart
CONFINEMENT
rapidity gap p
Incident hadrons retain their quantum numbers
remaining colorless
pseudo-
DECONFINEMENT
POMERON p p p p
Goal: understand the QCD nature of the diffractive exchange
EDS-2011 Vietnam
CDF Diffraction and Exclusive Production

40. Gap survival probability
EDS-2011 Vietnam
CDF Diffraction and Exclusive Production

41. 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 jitter
@ CDF
W/lowlum data
EDS-2011 Vietnam
CDF Diffraction and Exclusive Production

42. x & b dependence of FDjj – Run I
Pomeron dominated
EDS-2011 Vietnam
CDF Diffraction and Exclusive Production

43. Diffractive dijets @ Tevatronp
jet
reorganize
EDS-2011 Vietnam
CDF Diffraction and Exclusive Production

44. CDF Diffraction and Exclusive Production
Diffractive HERA
J. Collins: factorization holds (but under what conditions?)
Pomeron exchange
Color reorganization e Q2 g* p
jet x
reorganize e g*
x,t p IP
Results favor color reorganization
EDS-2011 Vietnam
CDF Diffraction and Exclusive Production