Constraints on PDF uncertainties from CDF DIS 2006, Tsukuba 22.04.2006 Cigdem Issever for the

1. Constraints on PDF uncertainties from CDF DIS 2006, Tsukuba 22.04.2006 Cigdem Issever for the CDF Collaboration University of Oxford

2. Outline • Introduction • Tevatron & CDF detector • EWK Results (95% of the talk) • Jet results (see talk “Inclusive jet production at the Tevatron (CDF)” of Olga Norniella in (HFS-5)) • Conclusion C. Issever

3. Chicago  Booster CDF DØ Tevatron p source Main Injector (new) Tevatron proton-antiproton collisions s = 1.96 TeV (Run I  1.8 TeV) 36 bunches: 396 ns crossing time Peak luminosity is now ~ 1032 cm-2 s-1 Ultimately 4 – 9 fb-1 by 2009 C. Issever

4. CDF Recorded Data Jet results with 1.0 fb-1 1.6 fb-1 delivered 1.2 fb-1 recorded EWK results C. Issever

5. CDF RUN II Detector • Upgraded for RUN II • New silicon tracking • New drift chamber • Increased muon coveraged • New TOF • New plug calorimeters Muon COT Tracker Si Detector PLUG EM Cal Had Cal CDF Data taking effi 80% - 85%. Silicon Detector C. Issever

6. EWK Physics – Input to PDFs Motivation • Test SM (precise measurements) • Constraints on PDFs • Search for physics beyond SM • Important input to LHC Outlook • W forward cross section, 223/pb • Z →ττ and μμ cross Section, 330/pb • W charge asymmetry, 170/pb C. Issever

7. ET>25GeV W/Z Gauge Bosons Identification • At hadronic collider W and Z bosons hadronic decays are overwhelmed by QCD background.  identification through leptonic decays We Z ET>20GeV PT>20GeV Position of μ consistent with extrapolated track PT>20GeV W±signature: Isolated Energetic Lepton + ET Z Signature: Two Isolated Energetic Leptons (opposite charge) C. Issever

8. W cross section in the forward region Extension into forward region: 1.2 < |η| < 2.8 using calorimeter seeded tracking Complementary to central C. Issever

9. W cross section in the forward region Systematics on A = 0.2567: 48165 ~4.8% 2% 0.07 Axε C. Issever

10. W cross section in the forward region 223pb-1 σ = 2.796 +/-0.013(stat) + 0.095 – 0.090 (syst) +/- 0.168 (lum.)nb. NNLO σ(pp→W) @ 1.96 TeV, Stirling, van Neerven = 2.687 +- 0.054(Th) C. Issever

11. Central-to-Forward W vis. cross section ratio s(visible)=sTOT*A where A is the kin. and geo accept. • Strategy: assign sys uncertainties but PDF, NLO/NNLO effect to svis • In this way: • Most of the luminosity uncertainty cancels in the ratio • All other uncertainties are uncorrelated • Accuracy can be used to constrain PDFs C. Issever

12. Central-to-Forward W vis. cross section ratio • svis(central) =664.2±11.7 pb(Ete>25, ETn>25, |hele|<1) • svis(forward) =718±21 pb(Ete>20, ETn>25, 1.2<|hele|<2.8) • svis(central)/svis(forward) =0.925±0.033 • 1% assigned as luminosity syst. (slightly overestimate) • NLO ratios (taking into account correlations between central and forward): • CTEQ= 0.9243±0.037 • MRST01E= 0.94137±0.011 • Most uncertainties will go down with more data  useful to constrain PDFs C. Issever

13. Z → μμ cross section (|η| < 1) using 337 pb-1 337pb-1 116 66 σ=261.2 ± 2.7 (stat) + 5.8 - 6.9 (sys) ± 15.1 (lum) pb NNLO @ 1.96 TeV Stirling, van Neerven σ(pp→Z)=251.3+-0.5(Th) C. Issever

14. Z →τeτh cross section using 349 pb-1 • 316 signal events • 60 % τ identification efficiency and 5% acceptance • Most systematics are data driven will be reduced with more stat. σ=265+-20(stat)+-21(syst)+-15(lumi) pb C. Issever

15. Cross section summary new C. Issever

16. e+ W+ W+ W- proton anti-proton n yW antiproton proton W Charge Asymmetry Asymmetry in W production complicated by unknown n pz use lepton asymmetry: which convolves W production with V-A decay. C. Issever

17. W Charge Asymmetry Run II 170pb-1 A as function of ET provides better probe of x dependence. Statistic allowed two bins. Will be included into next generation of PDFs. C. Issever

18. W Charge Asymmetry – new method Lepton asymmetry has turn over at high |η| due to V-A W charge asymmetry does not have this effect, so we don’t purely probe high yW • Determination of yW with W mass constrain gives 2 possible solutions. • Evaluate weight factor F1,2 for each y1,2 solution. • Parameterize F1,2 with • the angular distribution of (1+-cosΘ*)2 • with W cross section, σ(yW), but this depends on asymmetry • Iterative procedure!! C. Issever

19. W charge asymmetry – new method Iterative procedure • Smaller statistical errors • Greater sensitivity • No additional systematics due to new method C. Issever

20. Jet Midpoint jet cross section Good agreement with NLO More details see talk of Olga Norniella in (HFS-5): Jets 1 C. Issever

21. Results with KT: Data/NLO; 1fb-1 IR and CL safe No splitting or merging Measurements in the forward region will allow to reduce the PDFs uncertainties C. Issever

22. Conclusions New cross section measurements from CDF • W → eν in forward region (1.2 < |η| < 2.8) using 223 pb-1 • Central-to-forward W vis cross section ratio • Z → μμ using 337 pb-1 • Z → τeτh using 349pb-1 • Inclusive Jets with Mitpoint using 1.04 fb-1 • Inclusive Jet s with Kt algorithm using 0.96 fb-1 Excellent base for next set of analyses • dσ/dy for W → eν • dσ/dpt for Z → μμ • Tau widely used in SM measurements and SUSY, Higgs New generation of W&Z measurements (R, W Charge Asymmetry, … ) on the way !! C. Issever

23. Backup Slides C. Issever

24. W forward cross section C. Issever

25. Z → μμ cross section (|η| < 1) C. Issever

26. Z →τeτh cross section • taus difficult to reconstruct at hadron colliders • Z→ττ exploits event topology to suppress backgrounds (QCD&W+jet) CDF strategy for hadronic tau reconstruction: • Charge tracks  define signal and isolation cone (shrinking cone vs. E) isolation: require no tracks in isolation cone • Hadronic calorimeter cluster (to suppress e background) • π0 required in isolation cone (identified by shower maximum detector) = 30o • Z→ττ event selection: • τ→e: electron + isolated track (ET>10 GeV) • τ→h: PT(seed) > 6 GeV & PT(signal)>15 GeV • remove backgrounds by event topology cuts C. Issever

27. Z→ττ cross section C. Issever

28. Z→ττ cross section -- Systematics C. Issever

29. W Asymmetry – new method Leading order W production from Bo Young Han C. Issever

30. I.The angular distribution of ( )2 from W production • in Collin-Soper frame • The W production Probability from angular distribution ratio of two angular distributions at each rapidity from Bo Young Han C. Issever

31. II. Weight must also depend on W+- cross-section. • But cross-sections depend on W asymmetry! • This method must be iterated. III. Iteration procedure Input data reconstruction measuring asymmetry if no, min( ) F1 Fn the closest asymmetry to data assumed sample new assumed sample No Yes from Bo Young Han C. Issever

32. Sensitivity Study • , 400pb-1 MC data generated by Pythia • Selecting W events • high PT electron : ET > 25 GeV • Missing ET > 25 GeV • Used CTEQ6M errors PDF 40 sets for PDF uncertainty • Comparison of statistical uncertainty between lepton and W boson asymmetry • Our method has statistical sensitivity to probe PDFs from Bo Young Han C. Issever

33. Systematic Uncertainty Weight Factors depend on Q(yW, PtW) and σ(yW) • Ratio of two angular distributions, Q(yW, PtW) • PDF dependence • W cross section, σ(yW) • PDF dependence from Bo Young Han C. Issever

34. Systematic Uncertainty (cont.) The uncertainties from the energy measurement • Energy scale • Energy resolution (not yet) • Electron ET scale • ±0.1%(1σ) : |η| < 1.1 • ±0.15%(1σ) : |η| > 1.1 • Missing ET scale • W boson Recoil energy tuning from Bo Young Han C. Issever