1. IMFP2006 - Day 3 April 5, 2006 Rick Field – Florida/CDF/CMSPage 1 XXXIV International Meeting on Fundamental Physics Rick Field University of Florida (for the CDF & D0 Collaborations) CDF Run 2 Real Colegio Maria Cristina, El Escorial, Spain From HERA and the TEVATRON to the LHC Physics at the Tevatron 3 nd Lecture Photons, Bosons, and Jets at the Tevatron

2. IMFP2006 - Day 3 April 5, 2006 Rick Field – Florida/CDF/CMSPage 2 Photons, Bosons, and Jets at the Tevatron  The Direct Photon Cross-Section.  The  +  Cross-Section. Some Cross Sections Measured at the Tevatron  The  + Heavy Quark Cross-Section.  The Z-Boson Cross-Section.  The Inclusive Jet and DiJet Cross-Sections.  The W+Jets, Z+Jets, and Z+b-Jet Cross-Sections.  The W-Boson Cross-Section.  The W+  and Z+  Cross-Sections.  The W+W Cross-Section.  The W+Z and Z+Z Cross-Sections.  The Higgs → W+W Cross-Section.  H → W+W with 100 times more data! and comparisons with theory!

3. IMFP2006 - Day 3 April 5, 2006 Rick Field – Florida/CDF/CMSPage 3 The Direct Photon Cross-Section  DØ uses a neural network (NN) with track isolation and calorimeter shower shape variables to separate direct photons from background photons and  0 ’s!  g q q Highest p T (  ) is 442 GeV/c (3 events above 300 GeV/c not displayed)! Note rise at low p T !

4. IMFP2006 - Day 3 April 5, 2006 Rick Field – Florida/CDF/CMSPage 4  + b/c Cross Sections (CDF)  b/c-quark tag based on displaced vertices. Secondary vertex mass discriminates flavor. L = 67 pb -1

5. IMFP2006 - Day 3 April 5, 2006 Rick Field – Florida/CDF/CMSPage 5  + b/c Cross Sections (CDF)  PYTHIA Tune A correctly predicts the relative amount of u, d, s, c, b quarks within the photon events. CDF (pb)  (b+  40.6  19.5(stat)+7.4(sys)-7.8(sys)  (c+  486.2  152.9(stat)+86.5(sys)-90.9(sys)  + c  + b  T (  ) > 25 GeV L = 67 pb -1 PYTHIA Tune A!

6. IMFP2006 - Day 3 April 5, 2006 Rick Field – Florida/CDF/CMSPage 6  +  Cross Section (CDF)  Di-Photon cross section with 207 pb -1 of Run 2 data compared with next-to- leading order QCD predictions from DIPHOX and ResBos.  +  mass  +   L = 207 pb -1 QCD  + 

7. IMFP2006 - Day 3 April 5, 2006 Rick Field – Florida/CDF/CMSPage 7 Z-boson Cross Section (CDF)  Impressive agreement between experiment and NNLO theory (Stirling, van Neerven)! CDF (pb)NNLO (pb)  (Z→e + e - )254.9  3.3(stat)  4.6(sys)  15.2(lum)252.3  5.0 L = 72 pb -1 QCD Drell-Yan

8. IMFP2006 - Day 3 April 5, 2006 Rick Field – Florida/CDF/CMSPage 8 Z-boson Cross Section (CDF)  Impressive agreement between experiment and NNLO theory (Stirling, van Neerven)! CDF (pb)NNLO (pb)  (Z→  +  - )261.2  2.7(stat)  6.9(sys)  15.1(lum)252.3  5.0 L = 337 pb -1

9. IMFP2006 - Day 3 April 5, 2006 Rick Field – Florida/CDF/CMSPage 9 The Z→  Cross Section (CDF) Signal cone Isolation cone  Taus are difficult to reconstruct at hadron colliders Exploit event topology to suppress backgrounds (QCD & W+jet). Measurement of cross section important for Higgs and SUSY analyses.  CDF strategy of hadronic τ reconstruction: Study charged tracks define signal and isolation cone (isolation = require no tracks in isolation cone). Use hadronic calorimeter clusters (to suppress electron background). π 0 detected by the CES detector and required to be in the signal cone.  CES: resolution 2-3mm, proportional strip/wire drift chamber at 6X 0 of EM calorimeter.  Channel for Z→ττ: electron + isolated track One  decays to an electron: τ→e+X (E T (e) > 10 GeV). One  decays to hadrons: τ → h+X (p T > 15GeV/c).  Remove Drell-Yan e + e - and apply event topology cuts for non-Z background.

10. IMFP2006 - Day 3 April 5, 2006 Rick Field – Florida/CDF/CMSPage 10 The Z→  Cross Section (CDF)  CDF Z→ττ (350 pb -1 ): 316 Z→ττ candidates.  Novel method for background estimation: main contribution QCD.  τ identification efficiency ~60% with uncertainty about 3%! 1 and 3 tracks, opposite sign same sign, opposite sign CDF (pb)NNLO (pb)  (Z→  +  - )265  20(stat)  21(sys)  15(lum)252.3  5.0

11. IMFP2006 - Day 3 April 5, 2006 Rick Field – Florida/CDF/CMSPage 11 Higgs →  Search (CDF)  Data mass distribution agrees with SM expectation: M H > 120 GeV: 8.4±0.9 expected, 11 observed.  Fit mass distribution for Higgs Signal (MSSM scenario): Exclude 140 GeV Higgs at 95% C.L. Upper limit on cross section times branching ratio. 140 GeV Higgs Signal! events 1 event

12. IMFP2006 - Day 3 April 5, 2006 Rick Field – Florida/CDF/CMSPage 12 W-boson Cross Section (CDF)  (W) L CDF (pb)NNLO(pb) Central electrons 72 pb -1 2775  10(stat)  53(sys)  167(lum)2687  54 Forward electrons 223 pb -1 2815  13(stat)  94(sys)  169(lum)2687  54 CDFNNLO  (W)/  (Z)10.92  0.15(stat)  0.14(sys)10.69  0.08  Extend electron coverage to the forward region (1.2 < |  | < 2.8)! 48,144 W candidates ~4.5% background overall efficiency of signal ~7% W Acceptance

13. IMFP2006 - Day 3 April 5, 2006 Rick Field – Florida/CDF/CMSPage 13 20 Years of Measuring W & Z

14. IMFP2006 - Day 3 April 5, 2006 Rick Field – Florida/CDF/CMSPage 14 W+Jets Production (CDF)  Background to Top and Higgs Physics.  Testing ground for pQCD in multi-jet environment.  Restrict  W : W → e, |  e |< 1.1.  JETCLU jets (R=0.4): E T jets >15 GeV, |  jet | < 2.  Uncertainties dominated by background subtraction and Jet Energy Scale. LO predictions normalized to data integrated cross sections:  Shape comparison only! L = 320 pb -1

15. IMFP2006 - Day 3 April 5, 2006 Rick Field – Florida/CDF/CMSPage 15 W+Jets Production (CDF)  Important to study distributions and topological structure of W + Jets! More exhaustive comparisons expected soon!!! di-jet invariant mass distribution in the W+ ≥2 jet di-jet  R distribution in the W+ ≥2 jet LO predictions normalized to data integrated cross sections:  Shape comparison only!

16. IMFP2006 - Day 3 April 5, 2006 Rick Field – Florida/CDF/CMSPage 16 Z+Jets Production (DØ) MCFM: NLO for Z+1p or Z+2p  good description of the measured cross sections. ME + PS: with MADGRAPH tree level process up to 3 partons  reproduce shape of N jet distributions (Pythia used for PS).  Same physics as W + jets  (Z) ~  (W)/10, but Z→e + e - cleaner.  Central electrons (|  |<1.1).  MidPoint jets: (R = 0.5, p T > 20 GeV/c, |y jet |<2.5). Z+j L = 343 pb -1 P T distribution of the n th jet Z+2j Z+3j

17. IMFP2006 - Day 3 April 5, 2006 Rick Field – Florida/CDF/CMSPage 17 Z + b-Jet Production (CDF & DØ)  Important background for new physics! Extract fraction of b-tagged jets from secondary vertex mass distribution: NO assumption on the charm content. L = 335 pb -1 CDF Assumption on the charm content from theoretical prediction: N c =1.69N b. DØDØ Agreement with NLO prediction:  Leptonic decays for the Z.  Z associated with jets.  CDF: JETCLU, D0: MidPoint:  R = 0.7, |  jet | 20 GeV  Look for tagged jets in Z events. L = 180 pb -1

18. IMFP2006 - Day 3 April 5, 2006 Rick Field – Florida/CDF/CMSPage 18 W +  Cross Sections (CDF) CDF (pb)NLO (pb)  (W+  )*B R (W->l )19.7  1.7(stat)  2.0(sys)  1.1(lum)19.3  1.4 E T (  ) > 7 GeV R(l  ) > 0.7

19. IMFP2006 - Day 3 April 5, 2006 Rick Field – Florida/CDF/CMSPage 19 Z +  Cross Sections (CDF) CDF (pb)NLO (pb)  (Z+  )*B R (Z->ll)5.3  0.6(stat)  0.3(sys)  0.3(lum)5.4  0.3 E T (  ) > 7 GeV R(l  ) > 0.7 Note:  (W  )/  (Z  ) ≈ 4 while  (W)/  (Z) ≈ 11

20. IMFP2006 - Day 3 April 5, 2006 Rick Field – Florida/CDF/CMSPage 20 The W+W Cross-Section pb -1 CDF (pb)NLO (pb)  (WW) CDF 184 14.6+5.8(stat)-5.1(stat)  1.8(sys)  0.9(lum)12.4  0.8  (WW) DØ 240 13.8+4.3(stat)-3.8(stat)  1.2(sys)  0.9(lum)12.4  0.8 Campbell & Ellis 1999

21. IMFP2006 - Day 3 April 5, 2006 Rick Field – Florida/CDF/CMSPage 21 The W+W Cross-Section (CDF) L CDF (pb)NLO (pb)  (WW) 825 pb -1 13.7  2.3(stat)  1.6(sys)  1.2(lum)12.4  0.8  WW→dileptons + MET  Two leptons p T > 20 GeV/c.  Z veto.  MET > 20 GeV.  Zero jets with E T >15 GeV and |  |<2.5. Observe 95 events with 37.2 background! L = 825 pb -1 Missing ET!Lepton-Pair Mass! ET Sum! We are beginning to study the details of Di-Boson production at the Tevatron!

22. IMFP2006 - Day 3 April 5, 2006 Rick Field – Florida/CDF/CMSPage 22 The Z+W, Z+Z Cross Sections W+Z, Z+ZLimit (pb)NLO (pb) CDF (194 pb -1 ) sum < 15.2 (95% CL) 5.0  0.4 DØ (300 pb -1 ) W+Z < 13.3 (95% CL) 3.7  0.1 Upper Limits CDF (825 pb -1 ) W+Z < 6.34 (95% CL) 3.7  0.1 W+Z → trileptons + MET Observe 2 events with a background of 0.9±0.2!

23. IMFP2006 - Day 3 April 5, 2006 Rick Field – Florida/CDF/CMSPage 23 Di-Bosons at the Tevatron We are getting closer to the Higgs! W Z W+  Z+  W+W W+Z

24. IMFP2006 - Day 3 April 5, 2006 Rick Field – Florida/CDF/CMSPage 24 Generic Squark and Gluino Search  Selection:  3 jets with E T >125 GeV, 75 GeV and 25 GeV.  Missing E T >165 GeV.  H T =∑ jet E T > 350 GeV.  Missing E T not along a jet direction: Avoid jet mismeasurements.  Background:  W/Z+jets with W  l or Z .  Top.  QCD multijets: Mismeasured jet energies lead to missing E T. PYTHIA Tune A  Observe: 3, Expect: 4.1±1.5.

25. IMFP2006 - Day 3 April 5, 2006 Rick Field – Florida/CDF/CMSPage 25 Future Higgs & SUSY Searches  CDF and Tevatron running great!  Often world’s best constraints.  Many searches on SUSY, Higgs and other new particles.  Most currewnt analyses based on up to 350 pb -1 :  We will analyze 1 fb -1 by summer 2006.  Anticipate 4.4 - 8.6 fb -1 by 2009.  If Tevatron finds no new physics it will provide further important constraints:  And hopefully LHC will then do the job! If we find something the real fun starts: What Is It?

26. IMFP2006 - Day 3 April 5, 2006 Rick Field – Florida/CDF/CMSPage 26 Jets at Tevatron  Experimental Jets: The study of “real” jets requires a “jet algorithm” and the different algorithms correspond to different observables and give different results! “Theory Jets” Next-to-leading order parton level calculation 0, 1, 2, or 3 partons! “Tevatron Jets”  Experimental Jets: The study of “real” jets requires a good understanding of the calorimeter response!  Experimental Jets: To compare with NLO parton level (and measure structure functions) requires a good understanding of the “underlying event”!

27. IMFP2006 - Day 3 April 5, 2006 Rick Field – Florida/CDF/CMSPage 27 Jet Corrections  Calorimeter Jets:  We measure “jets” at the “hadron level” in the calorimeter.  We certainly want to correct the “jets” for the detector resolution and effieciency.  Also, we must correct the “jets” for “pile-up”.  Must correct what we measure back to the true “particle level” jets!  Particle Level Jets:  Do we want to make further model dependent corrections?  Do we want to try and subtract the “underlying event” from the “particle level” jets.  This cannot really be done, but if you trust the Monte-Carlo models modeling of the “underlying event” you can try and do it by using the Monte-Carlo models (use PYTHIA Tune A).  Parton Level Jets:  Do we want to use our data to try and extrapolate back to the parton level?  This also cannot really be done, but again if you trust the Monte- Carlo models you can try and do it by using the Monte-Carlo models. The “underlying event” consists of hard initial & final-state radiation plus the “beam-beam remnants” and possible multiple parton interactions.

28. IMFP2006 - Day 3 April 5, 2006 Rick Field – Florida/CDF/CMSPage 28 Inclusive Jet Cross Section (DØ )  MidPoint Cone Algorithm (R = 0.7, f merge = 0.5)  L = 378 pb -1  Two rapidity bins  Highest P T jet is 630 GeV/c  Compared with NLO QCD (JetRad, No R sep ) Log-Log Scale! Note that DØ does not make any corrections for hadronization and the “underlying event”!? They compare the NLO parton level directly to their hadron level data!

29. IMFP2006 - Day 3 April 5, 2006 Rick Field – Florida/CDF/CMSPage 29 Di-Jet Cross Section (DØ)  MidPoint Cone Algorithm (R = 0.7, f merge = 0.5)  L = 143 pb -1  |y jet | < 0.5  Compared with NLO QCD (JetRad, R sep = 1.3)  Update expected soon!

30. IMFP2006 - Day 3 April 5, 2006 Rick Field – Florida/CDF/CMSPage 30 Inclusive Jet Cross Section (CDF) Run I CDF Inclusive Jet Data (Statistical Errors Only) JetClu R CONE =0.7 0.1<|  |<0.7  R =  F =E T /2 R SEP =1.3 CTEQ4M PDFs CTEQ4HJ PDFs  Run 1 showed a possible excess at large jet E T (see below).  This resulted in new PDF’s with more gluons at large x.  The Run 2 data are consistent with the new structure functions (CTEQ6.1M). CTEQ4M CTEQ4HJ

31. IMFP2006 - Day 3 April 5, 2006 Rick Field – Florida/CDF/CMSPage 31 Inclusive Jet Cross Section (CDF)  MidPoint Cone Algorithm (R = 0.7, f merge = 0.75)  Data corrected to the hadron level  L = 1.04 fb -1  0.1 < |y jet | < 0.7  Compared with NLO QCD (JetRad, R sep = 1.3) Sensitive to UE + hadronization effects for P T < 200 GeV/c!

32. IMFP2006 - Day 3 April 5, 2006 Rick Field – Florida/CDF/CMSPage 32 K T Algorithm  kT Algorithm:  Cluster together calorimeter towers by their kT proximity.  Infrared and collinear safe at all orders of pQCD.  No splitting and merging.  No ad hoc Rsep parameter necessary to compare with parton level.  Every parton, particle, or tower is assigned to a “jet”.  No biases from seed towers.  Favored algorithm in e+e- annihilations! K T Algorithm Only towers with E T > 0.5 GeV are shown Raw Jet E T = 533 GeV Raw Jet E T = 618 GeV Will the K T algorithm be effective in the collider environment where there is an “underlying event”? CDF Run 2

33. IMFP2006 - Day 3 April 5, 2006 Rick Field – Florida/CDF/CMSPage 33 K T Inclusive Jet Cross Section (CDF)  K T Algorithm (D = 0.7)  Data corrected to the hadron level  L = 385 pb -1  0.1 < |y jet | < 0.7  Compared with NLO QCD (JetRad) corrected to the hadron level. Sensitive to UE + hadronization effects for P T < 300 GeV/c!

34. IMFP2006 - Day 3 April 5, 2006 Rick Field – Florida/CDF/CMSPage 34 Hadronization and “Underlying Event” Corrections  Compare the hadronization and “underlying event” corrections for th K T algorithm (D = 0.7) and the MidPoint algorithm (R = 0.7)! MidPoint Cone Algorithm (R = 0.7) The K T algorithm is slightly more sensitive to the “underlying event”!  We see that the K T algorithm (D = 0.7) is slightly more sensitive to the underlying event than the cone algorithm (R = 0.7), but with a good model of the “underlying event” both cross sections can be measured at the Tevatrun! Note that DØ does not make any corrections for hadronization and the “underlying event”!?

35. IMFP2006 - Day 3 April 5, 2006 Rick Field – Florida/CDF/CMSPage 35 K T Inclusive Jet Cross Section (CDF) Data at the “particle level”! NLO parton level theory corrected to the “particle level”! Correction factors applied to NLO theory! 7 7 8 D = 0.5D = 1.0 Corrections increase as D increases!

36. IMFP2006 - Day 3 April 5, 2006 Rick Field – Florida/CDF/CMSPage 36 High x Gluon PDF  Forward jets measurements put constraints on the high x gluon distribution! Uncertainty on gluon PDF (from CTEQ6) x Big uncertainty for high-x gluon PDF! from Run I

37. IMFP2006 - Day 3 April 5, 2006 Rick Field – Florida/CDF/CMSPage 37 K T Inclusive Jet Cross Section (CDF)  K T Algorithm (D = 0.7).  Data corrected to the hadron level.  L = 385 pb -1.  Five rapidity regions:  |y jet | < 0.1  0.1 < |y jet | < 0.7  0.7 < |y jet | < 1.1  1.1 < |y jet | < 1.6  1.6 < |y jet | < 2.1  Compared with NLO QCD (JetRad) with CTEQ6.1 Excellent agreement over all rapidity ranges!

38. IMFP2006 - Day 3 April 5, 2006 Rick Field – Florida/CDF/CMSPage 38 Jet-Jet Correlations (DØ) Jet#1-Jet#2  Distribution  Jet#1-Jet#2  MidPoint Cone Algorithm (R = 0.7, f merge = 0.5)  L = 150 pb -1 (Phys. Rev. Lett. 94 221801 (2005))  Data/NLO agreement good. Data/HERWIG agreement good.  Data/PYTHIA agreement good provided PARP(67) = 1.0→4.0 (i.e. like Tune A, best fit 2.5).