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Electroweak Physics at the Tevatron: Results and Future Prospects

Explore the latest electroweak physics results from the Tevatron collider, including cross sections, leptonic decays, background constraints, and more. Learn about the CDF and DØ collaborations in deep-inelastic scattering. Susana Cabrera from Duke University presents insights into W/Z physics at the Tevatron.

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Electroweak Physics at the Tevatron: Results and Future Prospects

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  1. Electroweak results at the Tevatron Susana Cabrera for the CDF and D0 collaborations XXIIth International Workshop on Deep-Inelastic Scattering Susana Cabrera, Duke University

  2. Electroweak Physics at Run II and Beyond SM W cross section Lepton Universality W asymmetry Constrain PDFs Higgs Mass constrain Z cross section W mass Direct Γ(W) sin2(θW), Anomalous quark couplings R: Indirect Γ(W) Bkgs top and Higgs Z’ resonances Z Forward-Backward Asymmetry WW/W/Z  cross sections Anomalous TGC Susana Cabrera, Duke University

  3. TheTevatron collider in Run 2 • Increased instantaneous luminosity: • Typical(moving target):4-5 x 1031 cm–2 s-1 • Record: ~7.2 x 1031 cm–2 s-1 • Tevatron has delivered in total~450 pb−¹ • Medium term: FY2003 • Base goal: 230 pb−¹ Design: 310 pb−¹ • Long term, by the end of FY09 • Base goal: 4.4 fb−¹ Design: 8.5 fb−¹ • Tevatron is a proton-antiproton collider operating withEbeam=980 GeV • 36 p and p bunches 396 ns between bunch crossing. Susana Cabrera, Duke University

  4. Oct Jan Apr Jul Oct Jan Apr Jul Oct Jan 2002 2003 2004 200 pb-1 Total Luminosity (pb-1) 64 pb-1 CDF Run I Delivered To Tape Store Number Run II Luminosity:CDF • ~350pb−¹ on tape. • Data taking efficiency > 80% • Dead time typically <5% • dL~ 6% (from inel& acceptance systematic) • Physics Analyses: • Between 64 and 200 pb-1 taken Mar 2002 – Sep 2003 Susana Cabrera, Duke University

  5. Run II Luminosity:DØ • DØ has ~273pb−¹ on tape. • Data taking efficiency around 85% with full detector readout. • dL~ 6.5% (from inel) • dL~ 10% (2003 results) • Between 14 and 160 pb-1 taken July 2002 – Sep 2003 DØ data for Dis2004 . Susana Cabrera, Duke University

  6. CDF Run II Detector • From Run I: • Solenoid • Central muon system • Central calorimeter ||= 1. • New For Run II: • Front-end DAQ • Trigger:Track (L1) and Displaced Track (L2) • Silicon Tracker (8 Layers) ( 2.0) • Central Outer Tracker • ( 1.0) • Plug Calorimeters • (1.0  3.6) • Extended Muon Coverage ( 1.5, gaps filled in) ||=2. Susana Cabrera, Duke University

  7. e &  at CDF Run II • Loose : • High Pt isolated track pointing to a gap in the - coverage ||<1.2 • MIP requirements. • Tight  : • pointing to a  -stub ||<1. •  measured with Z  • Trigger : 88%-95% • ID  : 85%-90% • Central e: ||<1.2 • Et>20-25 GeV • EM cluster + Drift chamber track,Pt>10 GeV • Plug e: 1.2<||<2.0-2.8 • EM cluster (+ Silicon track) • measured with Zee Trigger : 100%, Et>30 GeV ID  : >[80-94]% Drift chamber • e& mis-identification probability measured with dijet events • Veto cosmics using timing information and track information. • Veto  from jets (mostly b) using calorimeter-Iso and track-Iso Susana Cabrera, Duke University

  8. Overview of DØ Detector • Excellent calorimetry, hermetic detector. • Upgraded  system for better  -ID Susana Cabrera, Duke University

  9. e/ p q Z(W) p q e/ () W/Z Physics at the Tevatron. • W/Z production: qq dominated. • RunII: millions of Ws and 100ks of Zs. • Leptonic decay modes to avoid high QCD background Wl BR~11% Zl+l- BR~3% Susana Cabrera, Duke University

  10. CDF BR(Ze+e-) L~72pb-1 h(1st e)  1.0 h(e)  1.0 h(2nd e)  2.8 Extended coverage in the forward   2.8 • 66 < m(ℓℓ)/GeVc-2 < 116 • Small backgrounds from QCD, Z/W→τless than 1.5%: 6218 • Systematics : ~5.7%(2003) ~2% (improved material description) (22.74 ± 0.48)% BR(Zee)=250.53.8 pb (NNLO theory: Martin,Roberts,Stirling,Thorne) Susana Cabrera, Duke University

  11. DØBR(Ze+e-) L~41.6pb-1 • Z → e+ e− signal: • 2 isolated central electrons ||<1.1 with Et>25 GeV • No track match requirement, but shower shape and EmFrac requirements. • 70 < m(ℓℓ)/GeVc-2 < 110 • QCD bkg shape from data, by fitting signal and bkg distributions. • 1139 candidates after bkg substraction. • A x =9.3% Bkg Bkg+MC Signal Data BR(Zee)=250.53.8 pb (NNLO theory: Martin,Roberts,Stirling,Thorne) Susana Cabrera, Duke University

  12. CDF BR(Z+-) L~72pb-1 • Z → +− signal: • Two opposite charge ’s Pt>20GeV : Both: isolation + MIP +track quality • 1st : + stub in CMUP or CMX. • Cosmic veto: timing plus d0 • 66 < m(ℓℓ)/GeVc-2 < 116 • Small backgrounds from QCD, Z/W→τ, cosmics (μ) less than 1.5% (13.3+13.5-11.8) • Systematics : ~4.8%(2003) ~2.8% BR(Z)=250.53.8 pb (NNLO theory: Martin,Roberts,Stirling,Thorne) Susana Cabrera, Duke University

  13. DØBR(Z+-) L~117pb-1 • Z → +− signal: Two opposite charge ’s Pt>15GeV , at least 1  isolated,cosmic veto: timing plus d0 • m(ℓℓ)/GeVc-2 > 30 • Very low Backgrounds: QCD bb (0.6  0.3)% Z    (0.5  0.1)% • 6126 candidates after bkg substraction A x =16.40% BR(Z)=250.53.8 pb (NNLO theory: Martin,Roberts,Stirling,Thorne) Susana Cabrera, Duke University

  14. Summary CDF & DØ BR(Zl+l-) Susana Cabrera, Duke University

  15. ·BR(W) = 2.62  0.07stat  0.21sys0.16lumnb CDF Wt and Z h+ℓ− Signals L~72pb-1 • Count tracks in 10o-cone and veto tracks in 30o isolation cone • Reconstruct 0 candidates in Shower Max detector • Combined mass < m() • Wt : 2345 in ~72 pb-1Background ~26 % (dominated QCD) Susana Cabrera, Duke University

  16. DØBR(Wl) L~41(e)pb-1 L~17.3 () pb-1 1 tight central e isolated Et>25 GeV Met>25 GeV 1 tight  isolated Pt>20 GeV Met>20 GeV W μn W  en BR(Wl)=268740 pb (NNLO theory: Martin,Roberts,Stirling,Thorne) Susana Cabrera, Duke University

  17. CDF BR(Wl) L~72pb-1 1 tight central e isolated Et>25 GeV Met>25 GeV 1 tight  isolated Pt>20 GeV Met>20 GeV • Systematics : ~3.7%(2003) ~2.2% BR(Wl)=268740 pb (NNLO theory: Martin,Roberts,Stirling,Thorne) Susana Cabrera, Duke University

  18. L~64pb-1 CDF BR(We) PLUG • Electron: Plug EM cluster: Et>20, 1.1<||<2.8 • ID:Had/Em,E/P and cal-Iso. • Silicon track matched with shower-max plug detector • Met>20 • Trigger: Met>15 & Plug EM cluster: Et>20 • Main systematics: plug energy scale, PDF,material BR(Wl)=268740 pb (NNLO theory: Martin,Roberts,Stirling,Thorne) Susana Cabrera, Duke University

  19. Summary CDF & DØ BR(Wl) Susana Cabrera, Duke University

  20. Summary CDF & DØ Susana Cabrera, Duke University

  21. Combining e and μ channels • Assuming lepton universality, combine W and Z results • correlated systematics effects accounted for Susana Cabrera, Duke University

  22. 3.3677±0.024 NNLO (PDG) From LEP: (3.366 ± 0.0002)% Re & R R BR(W→ℓν) and Γ(W) Using NNLO calculation Γ(W→ℓν)=226.4 ±0.4 MeV (PDG): Susana Cabrera, Duke University

  23. CDF & DØ BR(W→ℓν) and Γ(W) ‡NNLO@1.96 : 10.66 ± 0.05 (J.Stirling) Using the NNLO calculation of (Wℓℓ) Current World Ave: 2092 ± 40 MeV LEP direct measurement : 2150 ± 91 MeV Susana Cabrera, Duke University

  24. BR(W ) 0.99  0.04stat  0.07sys = BR(W e ) -e Universality in W Decays • Calculate R separately for e and μ channels: • From W  e and W  t  cross sections : Susana Cabrera, Duke University

  25. e+ θ e− P Forward-backward asymmetry • Unique at Tevatron (off Z pole) • Directly probes V,A sin2W,u, • d couplings to Z • Sensitive to New Physics: agreement with SM prediction. p (1st e)  1.0 (2nd e)  2.8 5438candidates in ~72pb-1 Susana Cabrera, Duke University

  26. Di-boson Production and TGC qq’WTGC WW  qqZTGC Z ZZ  Susana Cabrera, Duke University

  27. First: Select W l  0   DiBoson Production: W W(e) Et(e)>25 GeV, cal-iso CDF |e|<1.1 DØ|e|<2. 3 Et>25 GeV W() Pt()> 20 GeV, CDF ||<1.0 DØ ||<1.6 Et>20 GeV Then: select  CDF Et ()>7 GeV DØ Et ()>8 GeV R(,l)>0.7 GeV |  |<1.1 Cal & trk-iso Shower Maximum Detector Pre-shower Detector Susana Cabrera, Duke University

  28. CDF: W ·BR(pp Wg  ℓn ℓg) = 19.3  1.3pb NLO prediction (U. Baur): (W)BR(Wl) = 19.7 1.7 (stat)  2.0 (sys)  1.1 (lumi) pb Susana Cabrera, Duke University

  29. DØ W ·BR(pp Wg  ℓn ℓg) = 16.4  0.4pb NLO prediction (U. Baur): (W)BR(Wl) = 19.3 2.7 (stat)  6.1 (sys)  1.2 (lumi) pb Susana Cabrera, Duke University

  30. DiBoson: Z  NON-SM !! First: Select Z l+l- Z e+e-:Et(e)>25 GeV, |e|<2.8 Z +-: Pt>20 GeV, ||<1.1 Mll>40 GeV Then: select  Et ()>7 GeV R(,l)>0.7 GeV |  |<1.1 Cal & trk-iso Susana Cabrera, Duke University

  31. NLO prediction(U. Baur): (LO + ET(γ) dependent k –factors): ·BR(pp Z  ℓℓ) = 5.4  0.4pb CDF: Z  (Z)BR(Zll) =5.3 0.6 (stat)  0.4 (sys) 0.3 (lumi) pb Susana Cabrera, Duke University

  32. CDF: WW (Two approaches) Two complementary approaches • Dileptons: l+,l-: identified e, • Reject 76<Mll<106 & ET / ET <3 • ET>25 • No High Et jets • Opposite sign & Isolation  DY, Z  WZ/ZZ, Z  top dilepton  Fakes • (Identified e,) + track • Reject ET / ET <5.5 in all Mll • ET>25 • Njets<=1 • Opposite sign & Isolation ET / ET  Bkg with instrumental ET High S/B Increased acceptance Susana Cabrera, Duke University

  33. CDF: WW cross section NLO (MFCM, Ellis& Campbell) WW=12.50.8 pb e, l+track Susana Cabrera, Duke University

  34. CDF: WW Beyond SM ggHWW 140<MH<180GeV/c2 Anoumalous TGC WWZ/WW Susana Cabrera, Duke University

  35. CDF: WW e candidate Susana Cabrera, Duke University

  36. W mass prospects • CDF Run I (μ) mW = 80.465 ± 100(stat) ± 103(sys) MeV • CDF Run II for 250/pb estimate (μ): = X ± 55(stat) ± 80(sys) MeV Calorimeter: right energy scale and resolution direct extraction of (W) Z → μμ • Data • Simulation • Total background W → μν • Data • Simulation direct extraction of G(W) momentum scale J/Y(2-5 GeV)  (8-10 GeV) Z (high Pt) Mmm(GeV/c2) MT(m,n) (GeV/c2) Susana Cabrera, Duke University

  37. Conclusions • Electroweak measurements at the Tevatron: • Benchmarks to understand the CDF & DØ detectors. • Important backgrounds for Top and Higgs physics. • Ideal scenario to test the Standard Model. • Please tune in to the talks: • Higgs (S.Beauceron) SUSY (K.Kurca) Leptoquarks (D.Ryan) and other (A.Pompos) searches at the Tevatron. • Diboson Production cross section measurements  anomalous TGC. • Expect full set of publications based on 200 /pb between now and the end of 2004. Susana Cabrera, Duke University

  38. Backup slides Susana Cabrera, Duke University

  39. Electron Reconstruccion Calorimeter + tracking information • Central electron: ||<1.2 • EM cluster + COT track • Plug electron: 1.2<||<1.8 • EM cluster (+ Silicon track) • Isolation: fraction of E in a cone 0.4 • Loose electrons: Et>20-25 GeV, • Pt>10 GeV, Ehad/Eem, track quality and fiducial requirements. • Tight electrons: +E/P, shower profiles, track:showerMax matching •  measured with Zee • Trigger : 100%, Et>30 GeV • ID  : tight e >80% , loose e >94% • Large fractional energy deposit in EM sector. Track match requirement. • Isolation: fraction of energy in hollow cone between 0.2 –0.4 • Shower shape distribution,E/P •  measured with Zee • Trigger : 100% above 30 GeV • ID  > 90%, track matching included. • E/P:75-80% Mis-identification probability measured with dijet events Susana Cabrera, Duke University

  40. Muon Reconstruccion • Loose muon: • High Pt isolated track pointing to a gap in the muon coverage ||<1.2 • MIP requirements. • Tight muon: • High Pt isolated track pointing to a muon stub ||<1. •  measured with Z  • Trigger : 88%(CMUP)-95%(CMX) • ID  : 85%(CMUP)-90%(CMX) Calorimeter + tracking +  stub information. • -track measured twice: • Toroidal spectrometer: position and timing information before & after the magnet. • Precision Pt measured in central fiber tracker • Track match: position and P. •  measured with Z   • Trigger : 50% (single ) • Tracking  > 95%. • Isolation:91% Mis-identification probability measured with dijet events Veto cosmics using timing information and track information. Veto  from jets (mostly b) using isolation: calorimeter (CDF & DØ)and track (DØ) Susana Cabrera, Duke University

  41. DØZ  th+tℓ− Signals L = 68 pb-1 Z   ( )  (   + n0) Backgrounds - QCD  from bb or /K decay - W   or  + jet - Z    visible mass (GeV) Susana Cabrera, Duke University

  42. CDF: WW (III) Susana Cabrera, Duke University

  43. CDF: WW (IV) Susana Cabrera, Duke University

  44. TheTevatron collider in Run 2 • Tevatron is a proton-antiproton collider operating with Ebeam=980 GeV • 36 p and p bunches 396 ns between bunch crossing. • Run 1: 6x6 bunches with 3.5s • Increased instantaneous luminosity: • Typical: 4-5 x 1031 cm–2 s-1 • Record: 6.1 x 1031 cm–2 s-1 • Tevatron has delivered~430 pb−¹ • Long term, by the end of FY09 • Base goal: 4.4 fb−¹ • Design: 8.5 fb−¹ Susana Cabrera, Duke University

  45. CDF Run II Detector • From Run I: • Solenoid • Central muon system • Central calorimeter • New For Run II: • Front-end DAQ • Trigger:Track (L1) and Displaced Track (L2) • Silicon Tracker (8 Layers) ( 2.0) • Central Outer Tracker • ( 1.0) • Plug Calorimeters • (1.0  3.6) • Extended Muon Coverage ( 1.5, gaps filled in) Susana Cabrera, Duke University

  46. Overview of DØ Detector • New Inner tracking (silicon tracker, scintillating fiber tracker,preshowers) with 2T superconducting solenoid • Excellent calorimetry, hermetic detector. • Upgraded  system for better  -ID • Faster readout electronics, new trigger and DAQ. Susana Cabrera, Duke University

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