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The 1st year at CDF II

The 1st year at CDF II. M. Martinez IFAE-ATLAS Meeting, December 2005. Initial Notes. I will show you details about the first years of CDF II. However do not conclude that the history will repeat itself at ATLAS….

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The 1st year at CDF II

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  1. The 1st year at CDF II M. Martinez IFAE-ATLAS Meeting, December 2005

  2. Initial Notes • I will show you details about the first years of CDF II. However do not conclude that the history will repeat itself at ATLAS…. • Run II physics potential is/was based on the increase in luminosity compared to Run I (center-of-mass energy barely changed) • we were initially disappointed by the Tevatron delivered luminosity and the high proton losses (high beam backgrounds) • Run I --> Run II took 6 years (Run I data was deeply explored….still ongoing analyses when Run II data came) • CDF put the effort in confirming top quark discovery fast… big pressure from agencies…heavy Run I legacy in how to do things… • LHC is a discovery machine….we have to carefully decide which physics to do first in view of discovery potential & ATLAS performance….

  3. First Publications in Run I time CDF Publications and Preprints for 1989 • Measurement of the inclusive jet cross section • Measurement of W-boson production • Limits on masses of supersymmetric particles • Dijet angular distributions • Measurement of the mass and width of the Z boson • Search for heavy stable charged particles • K(s) production in p anti-p interactions CDF Publications and Preprints for 1988 • Transverse-momentum distributions of charged particles -> First tracking, then electrons and jets….no b-tagging

  4. Chicago  Booster CDF DØ Tevatron p source Main Injector (new) Tevatron Run II

  5. Tevatron II Performance • Tevatron operations scheduled by March 2001…then September 2001 • CDF declared data for physics in March 2002… • => 1st 6 months.. a combination of Tevatron and CDF commissioning work

  6. CDF Detector • Very Mature Collaboration • 800 physicists • 59 institutions • Upgraded Muon Detectors • New TOF Detector • New Plug Calorimeters • New Drift Chamber • New Silicon Tracking • New DAQ

  7. Notes about Commissioning • DAQ system was ready and working well before first collisions ….however it took time to achieve smooth operations…….. • COT and CAL worked well from the beginning….however Plug CALs were new and not understood (people focused on central measurements…..this is a consequence of Run I legacy…) • Muon Detectors worked well but new forward detectors (CMX) needed a longer commissioning period…affected by beam losses • TOF working well but difficult to achieve the designed 100 ps resolution • Silicon took LONG time ….by June 2002 >30% of the detector was still under commissioning….. • Tevatron beam conditions (high losses) showed the lack of shielding at CDF….additional shielding had to be installed….

  8. June 2002: CDF is back! • CDF taking data since March´02 • CDF performing reasonably well • COT tracking essentially understood • Ongoing commissioning for Silicon • Muons in central rapidity • CAL EM scale set with Zs • First jet distributions (hadronic e-scale to be understood) • First understanding of MET for Ws • High MET tail barely understood (large beam-backgrounds) • No results using b-tagging yet • Physics Results • W and Z cross sections • Bottom and Charm Physics using COT • Jet Raw distributions

  9. Status by Winter 2003 • Inclusive Jet Cross Section • W and Z Cross Sections • FB Asymmetries • Top Cross Section and Mass • DY production • Searches • …….. • No SUSY results until summer Tevatron Lumi steadily improving Still high losses challenges the silicon operations and data taking B-tagging still under study

  10. CDF II Data Samples • CDF was taking Physics Data since March ‘02 • More than 170 pb-1 collected on tape • ~8 pb-1/week • > 90% CDF data-taking efficiency Winter Conferences Tot. Lumi (pb-1) delivered CDF recorded Efficiency (%) Winter Phys. Results used samples between 50 – 91 pb-1 Store number

  11. Inclusive Jet Production Theoretical error dominated by PDF’s (gluon at high-x) range increased up to ~600 GeV Systematic errors dominated by 5% e-scale uncertainty…to be reduced …agreement within uncertainties…

  12. Highest Mass Dijet Event Dijet Mass = 1364 GeV ET = 666 GeV h= 0.43 CDF (f-r view) ET = 633 GeV h = -0.19

  13. .B(Z0l+l-) • Isolated leptons • Very Clean • Used for CAL/EMC • calibrations & ID • 72 pb-1 Zmm NNLO @ s=1.96 TeV: 252  9 pb

  14. asymmetry (Z0e+e-) • Forward-Backward Asymmetry • Direct probe of ,Z couplings (sensitive to new physics) • High mass unique to Tevatron • Results consistent with SM e+ q* e- …waiting for more data…

  15. .B(W ln) • Signature • Isolated lepton • Missing ET • High  & S/B • 72 pb-1 We Wm We NNLO @ s=1.96 TeV: 2.69  0.10 nb

  16. W/Z Production Cross Sections - NNLO Nucl. Phys. B359,343 (1991) Phys.Rev. Lett. 88,201801 (2002) …good agreement with NNLO predictions ….

  17. W and Lepton Universality • Clean W decays • Baseline for ’s analyses 2345 candidates (72pb-1) Backg. ~26% (mainly QCD)

  18. ℓ jet n b-jet b-jet jet ℓ b-jet ℓ b-jet Top Quark Physics • Top decays as a free quark • top ~ 4x10-25s • BR(t->Wb) ~100% • Measured decay signals (to date) • Dilepton • 2 high-pT leptons, 2 b jets • Missing ET • BR (e, : ~5%) • Backg-> W+jets, fakes • Lepton + Jets • 1 high-pT lepton, 4 jets (2 b’s), • Missing ET • BR (e,: ~30%) • Backg->

  19. ℓ jet n b-jet b-jet jet Jet3 Jet2 Lego view Jet1 Jet4 µ • muon • electron • photon Lepton + Jets Candidate pT() = 54.4 GeV ETj= 96.7, 65,8, 54.8, 33.8 GeV Missing ET= 40.8 GeV

  20. Top Cross Section (Dilepton Channel) • Signature • Two high pT Isolated leptons • Veto Z, cosmic, conversion • (ET,l/j)>20o, or Missing ET>50 GeV • Missing ET > 25 GeV • Two jets with ET>10 GeV • Total ET > 200 GeV • Expect S/B ~ 9, S~2.5 • Find 5 candidate events in 72 pb-1 • Expect 0.3 ± 0.12 backg. events tt=13.2 ±5.0stat ±1.5syspb

  21. Top Cross Section (Lepton + Jet(s) Channel) • Signature • One high pT Isolated lepton • Veto Z, cosmic, conversion • Missing ET > 20 GeV • 3 or more jets with ET>15 GeV • 1 jet with secondary vertex tag • B tag improves S/B 1/6 3/1 • 15 candidate events in 57.5 pb-1 • Expect 3.8 ± 0.5 backg. events tt=5.3 ±1.9stat ±0.8syspb control region signal region

  22. Top Production Cross Section …updated results to come during summer…

  23. W+ b-jet n X t t jet W- jet b-jet Top Mass (Lepton + Jets Channel) • Lepton + 4 jets (no b-tags required) • 24 possible combinations • 12 for parton-jet match • Every combination has 2 solutions for neutrino’s z-component • Impose • 2-C fit applied and combination with smallest value is chosen 24 combinations

  24. signal background Top Mass Templates • Reconstructed top masses from data are compared to parameterized templates of top and background Monte Carlo events • A likelihood method is used to extract the the final top mass value

  25. Top Mass • Use a continuous likelihood method to extract top mass and statistical uncertainty • Mtop is the minimum of the log-likelihood distribution • top corresponds to a change of 0.5 units in the log-likelihood Mtop = 171.2  13.4stat  9.9sysGeV/c2 CDF Run 1 combined: Mtop = 176.1 ± 6.5 GeV/c2 ..syst. uncertainty dominated by jet e-scale…

  26. WWllnn Production • Signature • Dileptons & Missing ET • Df(Missing ET , l/j) • 72 pb-1 e m Consistent with SM ….waiting for more data…

  27. WgProduction • Signature • One high pT lepton • One photon (R(-l)>0.7) • Missing ET SM: •B(W-->l) = 18.7 ±1.3 pb

  28. Zg Production • Signature • Two high pT leptons • One photon (R(-l)>0.7) • SM: •B(Z-->ll) = 5.4 ± 0.4 pb

  29. Following up Run I anomalies gg ee + Missing ET It was proposed as possible SUSY candidate ..e.g., radiative decay of neutralinos… (GMSB scenario where gravitino is the LSP)

  30. Run II Diphoton Search Two central photons ET>13 GeV Cosmic and beam halo rejection Good agreement with SM …no Diphoton + Lepton(s) Events Observed…

  31. Drell-YanSpectra • Two high pt isolated electrons • No significant Missing Et • Two high pt isolated muons • veto against cosmic rays No excess observed

  32. Z’ Limits New Limits @ 95% C.L. (SM-like coupling) sBr(Z’-> ll) < 0.1 pb for M(Z’) >500 GeV

  33. Randall-Sundrum Graviton Limits • Two free parameters : • M(Graviton), k/M(Planck) • k/M(Planck) determines the • coupling and resonance width Excited graviton (spin-2 KK resonance)

  34. First Generation Scalar LeptoQuarks • LQLQ  e+e-qq • 2 high ET electrons, 2 jets • 0 events observed • Background: 3.4±3 events • Limit: M(LQ)>230GeV/c2 • LQLQ qq • 2 high ET jets, large ET • 42 events observed • Background: 43±11 events • Exclusion:60<M(LQ)<107GeV

  35. Charged Massive Particles • Long-lived charged particle • Massive  Slow moving • Use time from TOF data • Define DTOF as difference w.rt. • a particle moving with speed = c • 7 events observed • (Background: 2.9±3.2 events) • Candidate: stop • NLSP in GMSB • Limit: M(stop) > 108 GeV

  36. Limits on Excited Fermions • Compositeness models • Clear Signature in • Two parameters:

  37. First Steps…towards SUSY • MET f distribution dominated by beam-related backgrounds and defects in the CAL calibrations • Now we understand the features and after some minimum cuts things look better (but not perfect) • Vertex • At least two jets • MET > 45 GeV • additional cuts under study CDF …almost there…..

  38. Summary • Tevatron had a very slow startup with low luminosity and high proton losses • CDF detector worked well with great efficiency but silicon (b-tagging) and forward calorimeters needed more time to be understood and used in analyses • First year´s physics results heavily relied on leptons (also driven by top and electroweak needs) • Due to beam conditions large MET samples (SUSY) needed lots of work for first results to be produced…. • My conclusion……

  39. La Tomatina, Buñol (Valencia) New Physics ATLAS Let´s talk about how do we prepare ourselves for this!

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