Mike Albrow FermilabISMD 2008, Sept 2008Central Exclusive Production at the Tevatron 1 Central Exclusive Production at the Tevatron (CDF) Mike Albrow (Fermilab) for the CDF Collaboration Introduction ISR : π+ π- etc. Tevatron: e+e-, γγ, μ+μ-, J/ψ, ψ(2S), χ_c, Υ …. Z? LHC: Z, H, W+W-, … pp  p X p where X is a simple system completely measured JJ VeryFewParticle

Mike Albrow FermilabISMD 2008, Sept 2008Central Exclusive Production at the Tevatron 2 ISR – Tevatron -- LHC 1)Central Exclusive Production: 2)LHC: Study of Higgs through p + H + p, WW and ZZ FP420: R&D project; proposing extensions to ATLAS & CMS. pp p p p p p p G?H? Our measurements are the first 2-photon in hadron-hadron, and test both the production mechanisms and calibration techniques. ~ same diagram

Mike Albrow FermilabISMD 2008, Sept 2008Central Exclusive Production at the Tevatron 3 In collisions (through LEP energies  I L C) :  hadrons, and at high energy: WW  WW, WW  Z,H ; WZ  W In ep collisions (HERA) : gamma-IP  vector mesons ( too but buried?) In (ISR  Tevatron and LHC) : IP IP  hadrons (can be single hadron), Higgs, -IP  vector mesons (..,Y, Z(allowed but tiny))  l+l- ( too but buried?) In AA (RHIC, LHC) mainly (E-fields) -IP and IP+IP Central Exclusive Production in Different Machines New in CDF

Mike Albrow FermilabISMD 2008, Sept 2008Central Exclusive Production at the Tevatron 4 Central Exclusive Production is very clean, ~ no backgrounds Rapidity y ~ 7.4 ~ -7.4 p |y| < 1 With rapidity gaps > 6 on both sides, t-channel exchanges are very limited: Charge Q = 0, No color, and spin J >= 1.0 Allowed exchanges: only photons, IP = pomeron {~gg} Odderon {~ggg} not yet observed, Z (but p would always break up!) p t only from, continuum. only from IPIP. only from IP, OIP(?)

Mike Albrow FermilabISMD 2008, Sept 2008Central Exclusive Production at the Tevatron 5 Central Exclusive Production of Higgs Higgs has vacuum quantum numbers, vacuum has Higgs field. So pp  p+H+p is possible. Allowed states: Process is gg  H through t-loop as usual with another g-exchange to cancel color and even leave p’s in ground state. If measure p’s: H ! Aim: be limited by incoming beam momentum spread MGA+Rostovtsev: hep-ph/ J >= 2 strongly suppressed at small p angle (t) t 4-vectors

Mike Albrow FermilabISMD 2008, Sept 2008Central Exclusive Production at the Tevatron 6 G(1710)?? Structures not well understood beyond f(980) Not studied at higher Central Exclusive Production at ISR = 63 GeV (AFS) 3500 events/25 MeV DPE  would be great for G-spectroscopy. Waiting to be done at Tevatron! Student? Axial Field Spectrometer (R807) Added very forward drift chambers D.P.E. & Search for “Glueballs” data p p ALSO

Mike Albrow FermilabISMD 2008, Sept 2008Central Exclusive Production at the Tevatron 7 CDF Detector at Fermilab Tevatron MiniPlugs 980 GeV p 980 GeV pbar Muon Chambers Calorimeters

Mike Albrow FermilabISMD 2008, Sept 2008Central Exclusive Production at the Tevatron 8 Installed very forward Beam Shower Counters (BSC) for rapidity gaps and scintillating fiber trackers in Roman pots for pbar detection Not at all to scale! Roman pot detectors 20mm x 20mm 55 m downstream. Beam Shower Counters BSC tight around pipe. Full coverage –7.4 < < +7.4 by beam shower counters In this talk I do not use Roman pots; do not have acceptance for low mass

Mike Albrow FermilabISMD 2008, Sept 2008Central Exclusive Production at the Tevatron 9 16 events QED process : collisions in pp Monte Carlos : LPAIR, GRAPE, STARLIGHT Exclusive Electron-Positron Production in Hadron Collisions (CDF) Phys.Rev.Lett 98,112001(2007)

Mike Albrow FermilabISMD 2008, Sept 2008Central Exclusive Production at the Tevatron 10 Khoze, Martin and Ryskin, hep-ph/ , Eur.Phys.J. C23: 311 (2002) KMR+Stirling hep-ph/ QCD diagram identical to pHp 36 fb Exclusive H Theory Calibration: Exclusive 2-Photon MGA et al. (2001) hep-ex/ Tevatron Claim factor ~ 3 uncertainty ; Correlated to p+H+p

Mike Albrow FermilabISMD 2008, Sept 2008Central Exclusive Production at the Tevatron 11 3 candidates observed: It means exclusive H must happen (if H exists) and probably ~ 5 fb within factor ~ 3. is higher in MSSM Phys.Rev.Lett. 99, (2007) Exclusive Production in Hadron-Hadron Collisions Prediction V.A.Khoze et al. Eur. Phys. J C38, 475 (2005) (our cuts) = ( – 24) fb = –0.5 events. Cannot yet claim “discovery” as b/g study a posteriori, 2 events corresponds to ~ 90 fb, agreeing with Khoze et al. s ExHuME Monte Carlo James Monk & Andy Pilkington (MCR)

Mike Albrow FermilabISMD 2008, Sept 2008Central Exclusive Production at the Tevatron 12 New Results, hot off the press: Region rich in physics. First observations in (elastic) hadron-hadron: 1 & 2 ) Forward proton momenta precisely known: calibrate momentum scale of forward spectrometers for p + p  p + H + p at LHC. 3) Calibrate theory (x-sn) of p + H + p 1) 2) 3)

Mike Albrow FermilabISMD 2008, Sept 2008Central Exclusive Production at the Tevatron 13 There are 4, maybe 5, physics processes in this data! 1)2-photon (QED) production of the continuum (no resonances) We published this in 2007 for e+e- [ee] with M > 10 GeV (16 events as in QED) 2)Photon + IP  … photoproduction, as in ep at HERA 3)Photon + IP  … photoproduction, as in ep at HERA 4)IP + IP  IP = pomeron 1) 4) 2,3) or

Mike Albrow FermilabISMD 2008, Sept 2008Central Exclusive Production at the Tevatron 14 Data: Feb 2002 – March 2007 Luminosity (Good Runs) = 1.48/fb (+/- 6%) Trigger = muon + track +BSC1 gaps  2 muons Number of events on tape: ~ 1.6 million ) Reject cosmic ray events (ToF, colinearity) … 100% efficient Exclusivity: Require all detectors < noise cuts except in mumu direction

Mike Albrow FermilabISMD 2008, Sept 2008Central Exclusive Production at the Tevatron 15 Exclusivity cuts Want to be sure no other particles were produced. Take 0-bias = bunch crossing data. Put in two classes: non-interaction (dominated), no tracks, no CLC hits, no muon stubs interaction (dominated), all others For each sub-detector: 5 calorimeter regions, 3 BSC counter hodoscopes Find largest signal and plot it as [Log_10 max ADC counts] We did this for each of (11) periods of data, finding cut efficient at selecting “nothing” i.e. noise thresholds. Red mini-peak is not ineffiency, mainly mini-gaps with no pile-up. 500 ADC counts

Mike Albrow FermilabISMD 2008, Sept 2008Central Exclusive Production at the Tevatron 16 Eff(excl) = 0.093, 1.48/fb  (139 +/- 8) /pb (6%) 36 bunch x bunch crossings Have different luminosities Distribution over a “period” Exclusive efficiency Exclusive efficiency x L(bunch) Integral = L_1(effective) – no PU

Mike Albrow FermilabISMD 2008, Sept 2008Central Exclusive Production at the Tevatron 17 Very well fit by empirical function: F = 0.1 at M = 3.05 F = 0.6 asymptotically Single muon acceptance > 90% for pT > 1.5 GeV. Lower pT range out in calorimeters

Mike Albrow FermilabISMD 2008, Sept 2008Central Exclusive Production at the Tevatron 18

Mike Albrow FermilabISMD 2008, Sept 2008Central Exclusive Production at the Tevatron events 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 Paper in preparation

Mike Albrow FermilabISMD 2008, Sept 2008Central Exclusive Production at the Tevatron 20 x QED spectrum ~ Only normalization A floating STARLIGHT & LPAIR MCs Good description: v.low pT

Mike Albrow FermilabISMD 2008, Sept 2008Central Exclusive Production at the Tevatron 21 photoproduction (or possible odderon exchange) Kinematics well described by STARLIGHT MC Much broader pT,dphi than

Mike Albrow FermilabISMD 2008, Sept 2008Central Exclusive Production at the Tevatron 22 photoproduction (or possible odderon exchange) Kinematics well described by STARLIGHT MC Much broader pT,dphi than

Mike Albrow FermilabISMD 2008, Sept 2008Central Exclusive Production at the Tevatron 23 Dissociation background: Take (90 +/- 10%) for eff (BSC) (10 +/- 3)% Non-exclusive correction: QED: / J/psi, psi’ / Indication of small non-exclusive b/g as not described by MC

Mike Albrow FermilabISMD 2008, Sept 2008Central Exclusive Production at the Tevatron 24 Exclusive (<80 MeV) Best fit is with ~ 1/3 but with very large uncertainty Interpretations: (1) Large component (not supported by Method 2) (2) Decay simulations not precise (3) 1.5 sigma fluctuation (4) An odderon component (also  larger )

Mike Albrow FermilabISMD 2008, Sept 2008Central Exclusive Production at the Tevatron 25 Events with EM shower Good fits to mumu kinematics with only chi_c’s, if EM shower

Mike Albrow FermilabISMD 2008, Sept 2008Central Exclusive Production at the Tevatron 26 EmEt spectrum with J/psi mass cut: Empirical functional form: Fit shown (ET in MeV): A = B = 2.5 C = (per MeV) Fraction under 80 MeV small: 2.8 below 80 MeV (1% of J/psi) From varying A,B,C (1 +/- 1)% &  # chi_c = 68 +/- 8 Combine (1) and (2) : f = ( ) % Total number of chi_c = 68.2 (65.2 are above 80 MeV cut)

Mike Albrow FermilabISMD 2008, Sept 2008Central Exclusive Production at the Tevatron 27 Run,Evt: M=3.101, pT=1.54, dphi=2.18 Note: CLC and BSC all empty although we did not require that. CLC E empty CLC W empty BSC empty CENTRAL DRIFT CHAMBER CALORIMETERS: LEGO PLOT

Mike Albrow FermilabISMD 2008, Sept 2008Central Exclusive Production at the Tevatron 28 Summary of Results

Mike Albrow FermilabISMD 2008, Sept 2008Central Exclusive Production at the Tevatron 29 Summary of Results Assumed Suppressed by J_z=0 rule

Mike Albrow FermilabISMD 2008, Sept 2008Central Exclusive Production at the Tevatron 30 Odderon O, C = -1 partner to IP … at least 3 gluons In QCD but not yet observed. Possibly O + IP  & Search for Odderon exchange Signature: Excess of exclusive & and Upsilons Y over rate expected from photoproduction (tuned to HERA data). t(p)-distribution would be flatter and hence VM should have larger and Kinematic behavior different, but not well known. not known

Mike Albrow FermilabISMD 2008, Sept 2008Central Exclusive Production at the Tevatron 31 e.g. Schafer and Szczurek: arXiv: [hep-ph] Some predictions for J/psi photoproduction: Machado,Goncalves 3.0 nb Khoze, Martin, Ryskin Motyka and Watt: 3.4 nb Schafer & Szczurek ~ 2.8 nb Nystrand 2.2 nb Our result: nb Machado is considered too high by KMR Take We are consistent, & so we can put a limit on odderon exchange. If theory gets more precise, our limit can change

Mike Albrow FermilabISMD 2008, Sept 2008Central Exclusive Production at the Tevatron 32 Odderon Limits and ratios

Mike Albrow FermilabISMD 2008, Sept 2008Central Exclusive Production at the Tevatron 33 Invariant Mass Distribution - Upsilon Region Invariant Mass (n assoc_tracks = 0) pT(μμ) < 6GeV/c CDF Run II Preliminary Trigger: μ+μ- |η| 4 GeV/c Inclusive Photo-production of Y, Y’ (first observation in hadron-hadron) Y(1S) Y(2S)

Mike Albrow FermilabISMD 2008, Sept 2008Central Exclusive Production at the Tevatron 34 Exclusive Upsilon(1S) candidate Run/Event: / R-z, Muon hits Lego, threshold ET > 10 MeV Plugs, Miniplugs, CLC, BSC empty M ~ 9.4 GeV

Mike Albrow FermilabISMD 2008, Sept 2008Central Exclusive Production at the Tevatron 35 We have observed a candidate exclusive event with M ~ 64 GeV, which appears to be exclusive. Run Event Forward counters both sides CLC and BSC were empty. Roman pot had pbar track This is exactly the type of event for calibrating p(FP420) Search for Exclusive Z, and observe high mass lepton pairs. Spectrum extends to M(ll) > 100 GeV!

Mike Albrow FermilabISMD 2008, Sept 2008Central Exclusive Production at the Tevatron 36 FP420 : Forward Protons 420m downstream of CMS & ATLAS CMS CMS: Inner Vacuum Tank insertion 420 & 220m220 & 420m ||| ATLAS

Mike Albrow FermilabISMD 2008, Sept 2008Central Exclusive Production at the Tevatron 37 Summary We have observed the following exclusive states X in p + X + p at the Tevatron with CDF: These are all “first observations” for hadron-hadron “elastic”. (unless you call {A,Z} a hadron) processes agree with QED predictions Photoproduction of V agree with expectations & HERA. Hence limit on odderon exchange, near theory. IP+IP  within theoretical uncertainties, and demonstrates that exclusive H should happen, if H. Furthermore, exclusive di-leptons provide a calibration of forward p – spectrometers, momentum scale and resolution

Mike Albrow FermilabISMD 2008, Sept 2008Central Exclusive Production at the Tevatron 38 BACK UPS

Mike Albrow FermilabISMD 2008, Sept 2008Central Exclusive Production at the Tevatron 39 Cosmic rays would be at 0

Mike Albrow FermilabISMD 2008, Sept 2008Central Exclusive Production at the Tevatron 40 What is exclusive H cross section? H Calculation involves: gg  H (perturbative, standard, NLO) Unintegrated gluon densities Prob.(no other parton interaction) (“Gap survival”) Proton form factor Prob.(no gluon radiation  no hadrons) Sudakov Suppression Durham Gp: Khoze, Martin, Ryskin, Stirling hep-ph/ ~ 3 fb (M(H)=125 GeV) “factor ~ 3 uncertainty” 30 fb^-1  ~ 100 Ae events (Ae = acceptance, efficiency) But other estimates differ by “large” amounts! Need to “calibrate” theory! Exclusive