Mike Albrow FermilabISMD 2008, Sept 2008Central Exclusive Production at the Tevatron 1 Central Exclusive Production at the Tevatron (CDF) Mike Albrow (Fermilab)

  • View
    218

  • Download
    5

Embed Size (px)

Transcript

  • Slide 1
  • 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 : + - etc. Tevatron: e+e-, , +-, J/, (2S), _c, . Z? LHC: Z, H, W+W-, pp p X p where X is a simple system completely measured JJ VeryFewParticle
  • Slide 2
  • 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
  • Slide 3
  • 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
  • Slide 4
  • 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(?)
  • Slide 5
  • 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 ps in ground state. If measure ps: H ! Aim: be limited by incoming beam momentum spread MGA+Rostovtsev: hep-ph/0009336 J >= 2 strongly suppressed at small p angle (t) t 4-vectors
  • Slide 6
  • 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
  • Slide 7
  • 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
  • Slide 8
  • 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
  • Slide 9
  • 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)
  • Slide 10
  • Mike Albrow FermilabISMD 2008, Sept 2008Central Exclusive Production at the Tevatron 10 Khoze, Martin and Ryskin, hep-ph/0111078, Eur.Phys.J. C23: 311 (2002) KMR+Stirling hep-ph/0409037 QCD diagram identical to pHp 36 fb Exclusive H Theory Calibration: Exclusive 2-Photon MGA et al. (2001) hep-ex/0511057 Tevatron Claim factor ~ 3 uncertainty ; Correlated to p+H+p
  • Slide 11
  • 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. 99,242002 (2007) Exclusive Production in Hadron-Hadron Collisions Prediction V.A.Khoze et al. Eur. Phys. J C38, 475 (2005) (our cuts) = (36 +72 24) fb = 0.8 +1.6 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)
  • Slide 12
  • 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)
  • Slide 13
  • 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
  • Slide 14
  • 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
  • Slide 15
  • 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
  • Slide 16
  • 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
  • Slide 17
  • 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
  • Slide 18
  • Mike Albrow FermilabISMD 2008, Sept 2008Central Exclusive Production at the Tevatron 18
  • Slide 19
  • Mike Albrow FermilabISMD 2008, Sept 2008Central Exclusive Production at the Tevatron 19 402 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
  • Slide 20
  • 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
  • Slide 21
  • 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
  • Slide 22
  • 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
  • Slide 23
  • 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: 0.91 +/- 0.05 J/psi, psi 0.97 +/- 0.03 Indication of small non-exclusive b/g as not described by MC
  • Slide 24
  • Mike Albrow FermilabISMD 2008, Sept 2008Central Exclusive Production at the Tevatron 24 Exclusive (
  • Slide 25
  • Mike Albrow FermilabISMD 2008, Sept 2008Central Exclusive Production at the Tevatron 25 Events with EM shower Good fits to mumu kinematics with only chi_cs, if EM shower
  • Slide 26
  • 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 = 0.00025 B = 2.5 C = 0.0125 (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 = (1.9 +2.8 -1.9) % Total number of chi_c = 68.2 (65.2 are above 80 MeV c