1. James L Pinfold UK Forum
12/5/2018
James L Pinfold UK Forum

2. James L Pinfold UK Forum
CDF Detector
CDF :: Introduction
Muon Chambers
A Roman Pot deployed detector is placed on one side of CDF at at 60m from the IP. (RPS acceptance ~80% for 0.03 < x < 0.1 and |t| < 0.1)
Introduction e+e-  +- Charmonia Bottomonia Di-jets Z-boson Conclusion
12/5/2018
James L Pinfold UK Forum

3. Central Exclusive Physics
Central state
Proton/antiproton does not break up during interaction
pT ~ 0
> 3 rap-gap gg
, P, PP
> 3 rap-gap
 ~180o
Proton/antiproton does not break up during interaction
Both protons coherently scattered. Central state fully
specified and measured, unlike “inclusive” production:
Forward tagging of the p’s at the LHC with FP420/ 220m allows full reconstruction of the central state
Mass to ~3 GeV at ISR, ~100 GeV at Tevatron, ~700 GeV at LHC
Introduction e+e-  +- Charmonia Bottomonia Z-boson Di-jets Conclusion
12/5/2018
James L Pinfold UK Forum

4. James L Pinfold UK Forum
Exclusive Production Diagrams
Gamma-gamma Photoproduction QCD
Central Exclusive Production p g X IP
gap
QCD 
DPE X IP
gap
q-loop
In perturbative QCD the lowest order prototype of the pomeron is the color neutral system of two gluons.
Introduction e+e-  +- Charmonia Bottomonia Z-boson Di-jets Conclusion
12/5/2018
James L Pinfold UK Forum

5. James L Pinfold UK Forum
Exclusive e+e- Production (1) e+
QED e-
Central state produced via QED gg  e+e-
Protons do not dissociate
Only e+e- are produced  nothing else
Introduction e+e-  +- Charmonia Bottomonia Z-boson Di-jets Conclusion
12/5/2018
James L Pinfold UK Forum

6. James L Pinfold UK Forum
Exclusive e+e- Production (2)
Integrated luminosity → 532 ± 32 pb-1
DIFF_DIPHOTON Trigger:
2 EM clusters with ET>4GeV/c plus a veto on BSC 1 (E+W)
Exclusive e+e- events are selected by:
Reconstructing the e+e-
Requiring that there is no other activity in ||<7.4
Electrons have ET >5 GeV/c and |h| < 2
16 e+e- candidates selected
Backgrounds 1.9 ± 0.3 events:
dijet fake ( )
cosmic ( negligible)
inclusive distribution (0.3+/-0.1)
dissociation (1.6 ± 0.3) (these are also  e+e- where one (or both) proton(s) dissociate)
Introduction e+e-  +- Charmonia Bottomonia Z-boson Di-jets Conclusion
12/5/2018
James L Pinfold UK Forum

7. James L Pinfold UK Forum
Exclusive e+e- Production (3)
Kinematics of 16 event candidate sample match the predictions of the LPAIR signal MC
J.Vermaseren. Nucl. Phys., B , 1983 )- e+e- are collinear in f and have matching ET
Cross-section for gg  e+e- LPAIR theory: sLPAIR = 1.71 ± 0.01 pb
Introduction e+e-  +- Charmonia Bottomonia Z-boson Di-jets Conclusion
12/5/2018
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8. James L Pinfold UK Forum
Exclusive e+e- Production (4)
Agrees with LPAIR theory: sLPAIR = 1.71 ± 0.01 pb
Probability of 1.9  ≥16 = 1.3× corresponds to 5.5s “observation”
This is the first observation of exclusive two-photon produced e+e- interactions in p-p(bar) collisions
Also seen at RHIC (at low e+e- mass )– Phys. Rev C70:031902, 2004)
The LHC can, in principle, use such processes for luminosity measurement, etc.
We have many more candidates in new data with dedicated 2-EM shower trigger
Introduction e+e-  +- Charmonia Bottomonia Z-boson Di-jets Conclusion
12/5/2018
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9. James L Pinfold UK Forum
Exclusive  Study (1) X
Exclusive  events
Selected in the same way as e+e- (except tracks) agreement of  e+e- cross section gives confidence in analysis methodology
Introduction e+e-  +- Charmonia Bottomonia Z-boson Di-jets Conclusion
12/5/2018
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10. James L Pinfold UK Forum
Exclusive  Study (2)
3 candidate events are found in 532 pb-1 of Run II data.
Background 0.09 ± 0.04 events (dominated by misid. of excl.)
Good agreement on kinematics with ExHume MC
Based on the analytical results by KMR/Durham group (Khoze , Martin &Ryskin EPJ.C14: ,2000)
Introduction e+e-  +- Charmonia Bottomonia Z-boson Di-jets Conclusion
12/5/2018
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11. Exclusive  Candidates (1)
Possible p0p0/hh event
events predicted from ExHuME MC -
2 candidates are almost certainly  but the  hypotheses cannot be excluded
The 3rd candidate could be 
Introduction e+e-  +- Charmonia Bottomonia Z-boson Di-jets Conclusion
12/5/2018
James L Pinfold UK Forum

12. James L Pinfold UK Forum
Exclusive  Candidates (2)
The upper limit of the cross-section pp --> p  p is set at 410 fb with 95% confidence level ( taking into account the background + its uncertainty, signal selection efficiency, & Lint)
If 2 of the 3 candidates are gg events we obtain a cross section:
Durham Group: Khoze, Martin, Ryskin & Stirling hep-ph/ Eur.Phys.J C38 (2005) 475 : 38 fb with factor ~ 3 uncertainty
We have found >10 more candidates in data with new di-EM shower trig.
Introduction e+e-  +- Charmonia Bottomonia Z-boson Di-jets Conclusion
12/5/2018
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13. James L Pinfold UK Forum
Exclusive  Production (1)
Trigger (DIFF_CHIC_CMU1.5_PT1.5_TRK):
BSC Gap, east & west
muon + track (pt > 1.3 GeV/c; |h| < 1.2)
3.0 < M(muon + track) < 4.0 GeVc2
The existing sample corresponds to a lumi of 1.48 fb-1
Offline cuts
No other activity in the events (to an |h| of 7.4)
PT(m) > 1.4 GeV/c & |h(m)| < 0.6
Cosmic ray cuts (abs (TOF) < 3 ns)
Exclusivity cuts (same as for the e+e- paper)
STARLIGHT Monte Carlo simulation used (Klein & Nystrand)
Introduction e+e-  +- Charmonia Bottomonia Z-boson Di-jets Conclusion
12/5/2018
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14. Example exclusive m+m- event: Run 199559, Event 13120174
Exclusive  Production (2)
Example exclusive m+m- event: Run , Event
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12/5/2018
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15. James L Pinfold UK Forum
Exclusive  Production (4)
p + p  p +  + p
J
Fit: 2 Gaussians + QED continuum.
Masses 3.09, 3.68 GeV == PDG
Widths 15.8,16.7 MeV=resolution.
QED = generator x acceptance
3 amplitudes floating
402 events
(with no EM shower)
s
Introduction e+e-  +- Charmonia Bottomonia Z-boson Di-jets Conclusion
12/5/2018
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16. James L Pinfold UK Forum
Exclusive  Production (5)
ggm+m- continuum
IPJ+m-
IP sm+m-
Good agreement on kinematics with STARLIGHT MC (Klein & Nystrand )
Introduction e+e-  +- Charmonia Bottomonia Z-boson Di-jets Conclusion
12/5/2018
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17. James L Pinfold UK Forum
c  J/() + (soft) (1)
DPE
QCD 
Similar selection as  search with additional isolated EM shower req.
New ChicMC -Durham
Khoze,Martin,Ryskin,Stirling, EPJ C35, (2004), implemented by J. Stirling
Introduction e+e-  +- Charmonia Bottomonia Z-boson Di-jets Conclusion
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18. The ChiC-MC-Durham is a good fit the data
c  J/() + (soft) (2)
c  J/() + (soft)
The ChiC-MC-Durham is a good fit the data
Good fit to  kinematics from c, if there is an EM shower in the event
Introduction e+e-  +- Charmonia Bottomonia Z-boson Di-jets Conclusion
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19. James L Pinfold UK Forum
Estimating the c Contribution
Plot show fit of ET spectrum for events from J/ peak with:
EEMT tower > 100 MeV
Total number of c events: 68.2 ± 8.3
65.4 c events above the 80 MeV exclusivity cut
4.0 ± 1.6% c event background to exclusive J/ signal
Additional  inefficiency from: Conversions - 7%, Dead regions %
CHECK - Muon-pair events with an accompanying photon with ET > 80 MeV were from the J/ peak as expected if they are c decays
Introduction e+e-  +- Charmonia Bottomonia Z-boson Di-jets Conclusion
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20. James L Pinfold UK Forum
Backgrounds to Exclusive 
An important background is undetected proton fragmentation estimated using the LPAIR MC:
The proton frag. probability at the pp(p*) vertex is estimated as 17%
The proton frag. probability at the pIPp (p*) vertex is estimated as 24%
From the ratio of single diffractive frag. to elastic scattering at the Tevatron
The probability that all proton fragmentation products have || >7.4 is 14%
The probability that decay products may not be detected due to BSC inefficiency is 8%
Introduction e+e-  +- Charmonia Bottomonia Z-boson Di-jets Conclusion
12/5/2018
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21. James L Pinfold UK Forum
Exclusive  Production - Results
g
This QED cross-section is in principle very well understood
The  results agree with the Starlight (Klein & Nystrand) and LPAIR (Vermaseren) Monte Carlos
Predicted a cross-section of 2.18 ± 0.01 pb
Reminder - the ee results also agreed with the Starlight (Klein & Nystrand) and LPAIR (Vermaseren) Monte Carlos
Introduction e+e-  +- Charmonia Bottomonia Z-boson Di-jets Conclusion
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22. James L Pinfold UK Forum
Exclusive Charmonium - Results
IP J/ and IP s )
The J/ results (ds/dy|y=0) agrees with theoretical predictions:
V.A. Khoze , A.D. Martin , M.G. RyskinEur.Phys.J.C24: ,2002.
S.Klein and J.Nystrand, Starlight, Phys. Rev. Lett. 92: (2004).
L.Motyka and G.Watt, Phys. Rev. D78: (2008).
W.Schafer and A.Szczurek, Phys. Rev. D 76, (2007).
V.P.Goncalves and M.V.T.Machado, Eur. Phys. J. C 40, 519 (2005).
The (2s) result consistent with the Starlight prediction
R = (2s)/(1s) = 0.14 ± 0.05 is in agreement with the HERA value of R = ± at similar s(p) (H.Jung, Acta. Phys. Polon. Supp.1, 531 (2008))
d/dy|y=0 =
3.0 ± 0.3 nb
Introduction e+e-  +- Charmonia Bottomonia Z-boson Di-jets Conclusion
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23. James L Pinfold UK Forum
Exclusive c Production - Results
IP + IPc J/ (soft)
Theory
90 nb
The  -in theoretical errors - with:
T predictionof Khoze, Martin & Ryskin EPJ C19, 447 (2001), Erratum C (2001) & Khoze , Martin, Ryskin & Stirling, Eur.Phys.J.C35: ,2004
The calculation of Pasechnik, Szczurek & Teryaev, arXiv: [hep-ph].
In this analysis it is assumed that the produced c is 0++ (JPC)
NB double-diffractive production of exclusive axial vector (1++) & tensor (2++) quarkonium states are strongly suppressed (Khoze, Martin & Ryskin, EPJ C19, 447 (2001)
Caveat: the large BR of the c (1++) to J/ means it may contribute to our signal
Introduction e+e-  +- Charmonia Bottomonia Z-boson Di-jets Conclusion
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24. James L Pinfold UK Forum
Exclusive High Mass States (1)
Exclusive production of   , (1s,2s,3s), b & Z
Find Exclusive events using
Number of associated tracks = 0
Kinematics: Df  180o, DpT  0, (or SPT  0)
Trigger: 2 central muons with pT > 4 GeV/c
L = 890 pb-1 ~ 2.3 M events.
Remove cosmic rays (timing + colinearity)
Require on beam-line. Count additional (associated) tracks (n_ass) within 5 mm of m+m- vertex.
Cleanliness, backgrounds & acceptances being studied.
Introduction e+e-  +- Charmonia Bottomonia Z-boson Di-jets Conclusion
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25. James L Pinfold UK Forum
Exclusive Bottomonium States (1)
Invariant Mass - Upsilon Region
 > 120o, pT(+ + - ) < 1.5 GeV/c
Progress report - no cross-sections as yet!
CDF Run II Preliminary
Y(1S)
Clearly visible peaks
Y(1s),Y(2s),Y(3S) + continuum
More clean ’s than HERA!
Y(2S)
Continuum
Y(3S)
Continuum
~35% more data available
(but plots not blessed as yet)
Introduction e+e-  +- Charmonia Bottomonia Z-boson Di-jets Conclusion
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26. James L Pinfold UK Forum
Exclusive BottomoniumStates (2) H1
ZEUS
HERA data - resolution confuses (1s,2s,3s) low stats
Predictions of d/dy|y=0, from:
Motyka and Watt arXiv: pb
Cox, Forshaw & Sandapan - 12  1 pb
Klein& Nystrand ~12 pb
Bzdak,Motyka,Szymanowski & Cudell 0.8 – 5 – 9 pb
Introduction e+e-  +- Charmonia Bottomonia Z-boson Di-jets Conclusion
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27. James L Pinfold UK Forum
Exclusive Bottomonium States (3)
Now apply “super clean” exclusivity cuts as in low mass exclusive -pair analysis i.e. no pile-up, and only m-pairs detected
Run/Event: /
Lego, threshold ET > 10 MeV
Superclean Upsilon ET h h 
6 events in the 8 – 12 GeV/c2 region
4 events with mass > 12 GeV/c2.
(Most of reduction is killing pile-up)
Introduction e+e-  +- Charmonia Bottomonia Z-boson Di-jets Conclusion
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28. James L Pinfold UK Forum
Exclusive Bottomonium States (4)
IP + IPb   (soft)
Khoze, Martin, Ryskin,
Stirling, Eur.Phys.J.C35:
,2004. b 90
The exclusive (c) >> (b), follow two approaches:
1: Follow same basic analysis strategy as for the c
The efficiency of the c exclusivity criteria can be improved by a factor of ~6-10
2: Use kinematic constraints (+ only vertex) in the presence of pile-up
Not making exclusivity cuts gives us a factor of less than ~10 in the no. of events
Hard to estimate number of events expected as there is no hard measurement/prediction for the BR[b0(1P)  (1s)]
A challenging analysis - this is a work in progress!
Introduction e+e-  +- Charmonia Bottomonia Z-boson Di-jets Conclusion
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29. James L Pinfold UK Forum
Exclusive Z-boson Search (1)
Exclusive Z Production High mass  l+l- continuum
It is possible to produce Z bosons exclusively at the Tevatron
The SM rate is very low: ~0.3 fb so a signal would be BSM.
Motyka and Watt: PRD 78, (2008).
Select samples of high mass e+e- and +- pairs:
Z selection (denoted Zl+l-): pTl > 25 GeV, 82 < Mll < 98 GeV
l+l- selection (denoted l+l-): pTl > 20 GeV, Mll > 40 GeV
Require no additional tracks in event.
Only noise in the calorimeter (excluding the lepton + surrounding towers)
Introduction e+e-  +- Charmonia Bottomonia Z-boson Di-jets Conclusion
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30. James L Pinfold UK Forum
Exclusive Z-boson Search (2)
e+e-
E GeV
A reasonable fit the the LPAIR prediction for  l+l-
12 l+l- events were observed
8 of the events had no activity in the BSC (down to an || of 7.4)
Backgrounds are high mass QED continuum pairs and inclusive/ diffractive Z production
Introduction e+e-  +- Charmonia Bottomonia Z-boson Di-jets Conclusion
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31. James L Pinfold UK Forum
Exclusive Z-boson Search (3)
Results of Search for Exclusive Z Production
8 candidate exclusive di-lepton pairs   (ppllpp) = pb for:
Mll > 40 GeV, |l| < 4.0
LPAIR prediction:  =0.256 pb
1 event passes Z selection cuts (but with BSC energy) 
(Z) < % C.L.
Introduction e+e-  +- Charmonia Bottomonia Z-boson Di-jets Conclusion
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32. James L Pinfold UK Forum
Exclusive Di-jet Search (1) ET
JET
GAP h f
p detected in RP
(p not seen)
JET
Select DPE dijets: p + p → p + X (≥2jets+…) + gap
The events are selected from a sample of about 310 pb-1 of data collected with a dedicated diffractive trigger.
RPS (pbar-side) + J5 (CCAL/PCAL tower ET>5 GeV) + BSC1 veto on p-side
Introduction e+e-  +- Charmonia Bottomonia Z-boson Di-jets Conclusion
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33. Exclusive Di-jet Search
Examine the dijet mass fraction Rjj
Rjj =Mjetjet /MCENTRAL > 0.8 (to be“exclusive”)
Mjetjet  GeV/c2
Relative to R < 0.4 fraction of b-bbar
ExHuME: MC with
exclusive di-jets.
Exclusive gg → qq is suppressed by JZ=0 rule
Khoze, Martin & Ryskin, EPJ C19, 447 (2001))
Exploit this by looking at fraction of heavy flavor (b/c) jets
in dijet data as a function of Rjj - the effect is observed!
Introduction e+e-  +- Charmonia Bottomonia Z-boson Di-jets Conclusion
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34. James L Pinfold UK Forum
Exclusive Di-jet Cross-section
The ExHuME (KMR) is based on LO pQCD
DPEMC: based on Regge theory
The cross-section curves are calculated, using the CDF cuts, from:
Martin,Ryskin&Khoze, PRD56,5867, (1997)
Khoze,Martin&Ryskin, EPJ C23,311, (2002)
The solid curve is obtained by rescaling the parton (gluon) pT to the measured ET by ET=0.8pT
Khoze,Martin&Ryskin, arXiv:
The dashed curve assumes ET = 0.75pT .
Introduction e+e-  +- Charmonia Bottomonia Z-boson Di-jets Conclusion
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35. James L Pinfold UK Forum
Conclusions - Summary & Future
The observation of exclusive p-p p + e+e- + p production published in PRL (03/2007)
The study of exclusive p-p p + gg + p production published in PRL (12/2007)
The study of continuum and charmonium production via p-p p + m+m- + p of , J/y and (2s) is completed -PRL submitted (03/2009)
The study of the p-p  p cc p, via cc  J/y + g (soft) is completed and is part of the submitted PRL on Exclusive charmonium (see above)
The study of the exclusive bottomonium states: p-p p Y(1s)/ Y(1s)/ Y(1s) p and the exclusive b is underway
The search for exclusive Zll production is completed - the PRL was accepted (04/2009)
These results are:
1) First observations
at a p-p(p) collider
2) Compatible with
theory expectations in particular the predictions of the Durham group (KMR)
3) Compatible with HERA results (where applicable)
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36. James L Pinfold UK Forum
Conclusions - Summary & Future
FUTURE WORK
The work on the upsilon analysis and the b search continues
Studies of   e+e- and IP-IP   continue with new low ET di- photon trigger - (ET>3GeV) - more candidates seen.
Search for exclusive Z0’s continues with a new type analysis where events with pile-up are NOT rejected - giving a factor of ~10 increase in statistics.
A new trigger is being developed for exclusive and non-exclusive diffractive physics at CDF - a different (glue-rich) window on hadron spectroscopy, with:
Rapidity gaps defined by the CLC and BSC1 on both sides
At least 2 ToF counters (or adjacent pairs) above threshold
At least 2 central EM clusters with energy greater than 250 MeV
Trigger rate of ~200 events/sec in short dedicated run.
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37. James L Pinfold UK Forum
Conclusions - Summary & Future
IMPLICATIONS FOR THE LHC
Use of ggm+m- /e+e- as a lumi monitor
Study of ggm+m- & -p   m+m- as a calibration for FP420 is underway
Exclusive study of p-p J/Y, Y’, m+m- a good place for an odderon search
The process p-pgg/cc/ cb/ j-j are standard candles for the exclusive Higgs
According to the Durham Group’s theoretical framework the observation of these states means, in principle, we should see the CEP Higgs boson at the LHC
A proving ground for Central Exclusive Physics that will be exploited by the RP220 /FP420 forward proton spectrometers at the LHC
We are understanding that the LHC is a gg, g-p (g- IP) & IP- IP collider IP g IP
LHC p p g g IP
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38. James L Pinfold UK Forum
EXTRA SLIDES
12/5/2018
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39. James L Pinfold UK Forum
b-jet Suppression
12/5/2018
James L Pinfold UK Forum

40. Searching for the Odderon
The odderon is the C-odd partner of the pomeron - the hard odderon skeleton consists of three gluons in a color neutral state.
The Odderon would contribute to J/s peaks unlike the cc
If the J/ and (2s) cross sections were larger than expected for photoproduction, it would be evidence for odderon exchange.
Taking a theoretical value of d/dy |y=0(J/ ) = 3.0 ± 0.3 nb for photoproduction ( IP → J/), we can place a 95% C.L. upper limit d/dy |y=0(J/ ) < 2.3 nb for odderon exchange (O IP → J/ ).
This result is compatible with theory prediction of Bzdak, Motyka, Szymanowski & J-R.Cudell, PRD 75: (2007).
Introduction e+e-  +- Charmonia Bottomonia Z-boson Di-jets Conclusion
12/5/2018
James L Pinfold UK Forum

41. ppllpp cross-section
 = (Nevts - Nbck )/ (Acc.Lint)
Nevts
Nbck
Acc
Lint (pb-1)
 (pb) 
3  1.7
0.24  0.17
0.025  0.03
403  46
0.27  0.15
ee CC
4  2.0
0.031  0.033 
467 50
0.61  0.30
ee CP
5  2.2
0.048  0.050
0.020  0.002
467  50
0.50  0.24
Combining the three results gives:
 (ppllpp) = 0.39  0.12 pb for Mll > 35 GeV, |l| < 4.0
[LPAIR prediction:  = pb]
12/5/2018
James L Pinfold UK Forum

42. James L Pinfold UK Forum
Motivation: for Exclusive Studies
Motivations to study exclusive lepton pair production at the Tevatron:
Study , -p, DPE and Central Exclusive physics at the Tevatron
Potential to make measure luminosity at the LHC with precision ~5 % or better as we have a relatively well known QED x-section
Can be used as a control sample for exclusive processes whose cross- sections are not well predicted (Higgs, ...)
For alignment/calibration of forward proton spectrometers (FP420) at the LHC
Good place to search for the odderon
Introduction e+e-  +- Charmonia Bottomonia Z-boson Di-jets Conclusion
12/5/2018
James L Pinfold UK Forum

43. James L Pinfold UK Forum
12/5/2018
James L Pinfold UK Forum