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2nd July 20092nd July 2009 James L Pinfold EDS 2009James L Pinfold EDS 2009 11
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CDF :: Introduction
Muon Chambers
CDF Detector CDF Detector
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 Introduction ++-- -IP-IPJ/J/ & & (2s)(2s) IP-IP IP-IP cc J/ J/ + + Conclusion Conclusion
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Central Exclusive Physics Central Exclusive Physics Central state
, , P, PPP, PP
Proton/antiproton does not break up during interaction
Proton/antiproton does not break up during interaction
Both protons coherently scattered. Central state fully specified and measured, unlike “inclusive” production:
> 3 rap-gap > 3 rap-gap
Mass to ~3 GeV at ISR, ~100 GeV at Tevatron, ~700 GeV at LHC
Forward tagging of the p’s at the LHC with FP420/ 220m allows full reconstruction of the central state
~180o
pT ~ 0
Introduction Introduction ++-- -IP-IPJ/J/ & & (2s)(2s) IP-IP IP-IP cc J/ J/ + + Conclusion Conclusion
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Exclusive Production Diagrams Exclusive Production Diagrams
Gamma-gamma Photoproduction QCD
p
p
g
g
gX
q-loop X
IP
IP QCD DPE
gap
gap
In perturbative QCD the lowest order prototype of the pomeron is the color neutral system of two gluons - a gluon dipole.
Central Exclusive Production
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Exclusive Exclusive Production (1) Production (1)
• Trigger (DIFF_CHIC_CMU1.5_PT1.5_TRK):– BSC Gap, east & west
– muon + track (pt > 1.3 GeV/c; || < 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 || of 7.4)
– PT() > 1.4 GeV/c & |()| < 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)
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Exclusive Exclusive Production (2) Production (2)
Example exclusive +- event: Run 199559, Event 13120174
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402 events
Fit: 2 Gaussians + QED continuum.
Masses 3.09, 3.68 GeV == PDGWidths 15.8,16.7 MeV=resolution.
QED = generator x acceptance3 amplitudes floating
J
s
Exclusive Exclusive Production (4) Production (4)p + p p + + p
(with no EM shower)
IntroductionIntroduction ++-- -IP-IPJ/J/ & & (2s)(2s) IP-IP IP-IP cc J/ J/ + + Conclusion Conclusion
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Exclusive Exclusive Production (5) Production (5) IP sIPJ continuum
Good agreement on kinematics with STARLIGHT MC (Klein & Nystrand )IntroductionIntroduction ++-- -IP-IPJ/J/ & & (2s)(2s) IP-IPIP-IP cc J/ J/ + + Conclusion Conclusion
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•Similar selection as search with additional isolated EM shower req.
•New ChicMC -Durham
•Khoze,Martin,Ryskin,Stirling, EPJ C35, 211 (2004), implemented by J. Stirling
cc J/ J/(() + ) + (soft) (1)(soft) (1)
DPEQCD
IntroductionIntroduction ++-- -IP-IPJ/J/ & & (2s)(2s) IP-IPIP-IP cc J/ J/ + + Conclusion Conclusion
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cc J/ J/(() + ) +
(soft)(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
cc J/ J/(() + ) + (soft) (2)(soft) (2)
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• 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 - 5.0%
• CHECK - Muon-pair events with an accompanying photon with ET > 80 MeV were from the J/ peak as expected if they are c decays
Estimating the Estimating the cc Contribution Contribution
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• An important background is undetected proton fragmentation estimated using the LPAIR MC:
– The proton frag. probability at the pp(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%
Backgrounds to Exclusive Backgrounds to Exclusive
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• 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 ee results also agreed with the Starlight (Klein & Nystrand) and LPAIR (Vermaseren) Monte Carlos
Exclusive Exclusive Production - Results Production - Results
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• The J/ results (ds/dy|y=0) agrees with theoretical predictions:– V.A. Khoze , A.D. Martin , M.G. RyskinEur.Phys.J.C24:459-468,2002.– S.Klein and J.Nystrand, Starlight, Phys. Rev. Lett. 92:142003 (2004).– L.Motyka and G.Watt, Phys. Rev. D78:014023 (2008).– W.Schafer and A.Szczurek, Phys. Rev. D 76, 094014(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 =
0.166 ± 0.012 at similar s(p) (H.Jung, Acta. Phys. Polon. Supp.1, 531 (2008))
Exclusive Charmonium - Results Exclusive Charmonium - Results IP J/ and IP s )
d/dy|y=0 =3.0 ± 0.3 nb
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• The -in theoretical errors - with:– T predictionof Khoze, Martin & Ryskin EPJ C19, 447 (2001), Erratum C20 599 (2001) &
Khoze , Martin, Ryskin & Stirling, Eur.Phys.J.C35:211-220,2004
– The calculation of Pasechnik, Szczurek & Teryaev, arXiv:0902.1689[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
Exclusive Exclusive cc Production - Results Production - Results IP + IPc J/ (soft)
Theory90 nb
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Just Published (19th June 2009) Just Published (19th June 2009)
Principal authors: Albrow, Pinfold & Zhang
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• Our results agree with to the Durham Group’s theoretical predictions for the observation of these states
• IMPLICATIONS FOR THE LHC
– Use of /e+e- as a lumi monitor
– Study of & -p J/ as a calibration for FP420 is underway
– The process p-p/c/ b/ j-j are standard candles for the exclusive Higgs
• Thus, according to Durham Group predictions 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 , -p ( IP) & IP- IP collider
Final Words Final Words
p p
IP
IP
IP
LHC
IntroductionIntroduction ++-- -IP-IPJ/J/ & & (2s)(2s) IP-IP IP-IP cc J/ J/ + + ConclusionConclusion