XXXVI International Meeting on Fundamental Physics Physics at the Tevatron From IMFP2006 → IMFP2008 Rick Field University of Florida (for the CDF & D0 Collaborations) 2nd Lecture Bosons, Top, and Higgs Palacio de Jabalquinto, Baeza, Spain CDF Run 2 IMFP2008 - Day 2 February 5, 2008 Rick Field – Florida/CDF/CMS Page 1 Tevatron Performance The data collected since IMFP 2006 more than doubled the total data collected in Run 2! IMFP 2006 ~1.5 fb-1 delivered ~1.2 fb-1 recorded IMFP 2008 ~3.3 fb-1 delivered ~2.8 fb-1 recorded ~1.6 fb-1 Integrated Luminosity per Year 23 tt-pairs/month! Luminosity Records (IMFP 2006): Highest Initial Inst. Lum: ~1.8×1032 cm-2s-1 Integrated luminosity/week: 25 pb-1 Integrated luminosity/month: 92 pb-1 IMFP2008 - Day 2 February 5, 2008 Luminosity records (IMFP 2008): Highest Initial Inst. Lum: ~2.92×1032 cm-2s-1 Integrated luminosity/week: 45 pb-1 Integrated luminosity/month: 165 pb-1 Rick Field – Florida/CDF/CMS Page 2 Many New Tevatron Results! Some of the CDF Results since IMFP2006 IMFP2008 - Day 2 February 5, 2008 Observation of Bs-mixing: Δms = 17.77 ± 0.10 (stat) ± 0.07(sys). Observation of new baryon states: Sb and Xb. Observation of new charmless: B→hh states. Evidence for Do-Dobar mixing . Precision W mass measurement: Mw = 80.413 GeV (±48 MeV). cannot cover the(±2.2) GeV. PrecisionI Top mass possibility measurement: Mtop =all 170.5 great physics results from W-width measurement: 2.032 (±0.071) GeV.the Tevatron since IMFP WZ discovery (6-sigma): s = 5.0 (±1.7)2006! pb. I will show a few of the results! ZZ evidence (3-sigma). Single Top evidence (3-sigma) with 1.5 fb-1: s = 3.0 (±1.2) pb. |Vtb|= 1.02 ± 0.18 (exp) ± 0.07 (th). Significant exclusions/reach on many BSM models. Constant improvement in Higgs Sensitivity. Rick Field – Florida/CDF/CMS Page 3 Z-boson Cross Section (CDF) IMFP2006 QCD Drell-Yan Impressive agreement between experiment and NNLO theory (Stirling, van Neerven)! s(Z→e+e-) IMFP2008 - Day 2 February 5, 2008 CDF (pb) NNLO (pb) 254.93.3(stat)4.6(sys)15.2(lum) 252.35.0 Rick Field – Florida/CDF/CMS Page 4 Z-boson Cross Section (CDF) IMFP2006 Impressive agreement between experiment and NNLO theory (Stirling, van Neerven)! s(Z→m+m-) IMFP2008 - Day 2 February 5, 2008 CDF (pb) NNLO (pb) 261.22.7(stat)6.9(sys)15.1(lum) 252.35.0 Rick Field – Florida/CDF/CMS Page 5 Z-Boson Rapidity Distribution Measure ds/dy for since IMFP2006 Z→e+e-. Use electrons in the central (C) and plug (P) calorimeter. Parton momentum fractions x1 and x2 determine the Z boson rapidity, yZ. Production measurement in high yZ region probes high x region of PDF’s. Plug-plug electrons, ZPP, are used to probe the high x region! 1.1fb-1 91,362 events 66 < MZ < 116 GeV CDF Events Zcc IMFP2008 - Day 2 February 5, 2008 ZCC ZCP ZPP 28,097 46,676 16,589 Zcp Rick Field – Florida/CDF/CMS Plug-Plug electrons! Zpp Page 6 Z-Boson Rapidity Distribution since IMFP2006 CDF measured ds/dy for Z/g* compared with an NL0 calculation using CTEQ6.1M PDF. The NLO theory is scaled to the measured s(Z)! No PDF or luminosity uncertainties included. NLO+ +NNL0 CTEQ6.1 PDF NLL0 MRST PDF s(Z→e+e-) IMFP2008 - Day 2 February 5, 2008 CDF (pb) 263.3±0.9(stat)±3.8(sys) Rick Field – Florida/CDF/CMS NLO + MRST PDF NNLO (pb) 252.35.0 Page 7 The Z→tt Cross Section (CDF) 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. Signal cone 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). • π0 detected by the CES detector and required to be in the signal cone. CES: resolution 2-3mm, proportional strip/wire drift chamber at 6X0 of EM calorimeter. Isolation cone Channel for Z→ττ: electron + isolated track • One t decays to an electron: τ→e+X (ET(e) > 10 GeV) . • One t decays to hadrons: τ → h+X (pT > 15GeV/c). Remove Drell-Yan e+e- and apply event topology cuts for non-Z background. IMFP2008 - Day 2 February 5, 2008 Rick Field – Florida/CDF/CMS Page 8 The Z→tt 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 s(Z→t+t-) IMFP2008 - Day 2 February 5, 2008 IMFP2006 CDF (pb) NNLO (pb) 264 ± 23 (stat) ± 14 (sys) ± 15 (lum) 26520(stat)21(sys)15(lum) 252.35.0 Rick Field – Florida/CDF/CMS Page 9 Higgs → tt Search (CDF) 140 GeV Higgs Signal! IMFP2006 Data mass distribution agrees with SM expectation: • MH > 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. IMFP2008 - Day 2 February 5, 2008 Rick Field – Florida/CDF/CMS Page 10 Higgs → tt Search (CDF) since IMFP2006 No Significant Excess of events above SM background is observed! IMFP2008 - Day 2 February 5, 2008 Rick Field – Florida/CDF/CMS Page 11 W-boson Cross Section (CDF) Extend electron coverage to the forward region (1.2 < |h| < 2.8)! IMFP2006 48,144 W candidates ~4.5% background overall efficiency of signal ~7% s(W)/s(Z) s(W) CDF NNLO 10.920.15(stat)0.14(sys) 10.690.08 L CDF (pb) NNLO(pb) Central electrons 72 pb-1 277510(stat)53(sys)167(lum) 268754 Forward electrons 223 pb-1 281513(stat)94(sys)169(lum) 268754 IMFP2008 - Day 2 February 5, 2008 Rick Field – Florida/CDF/CMS Page 12 W-Boson Mass Measurement since IMFP2006 The Challenge: Do not know neutrino pz. No full mass reconstruction possible. Extract from a template fit to PT, MT, and Missing ET. Transverse mass: MW = 80413 ± 48 MeV/c2 Single most precise measurement to date! IMFP2008 - Day 2 February 5, 2008 Rick Field – Florida/CDF/CMS Page 13 W-Boson Width Measurement since IMFP2006 Model transverse mass distribution over range 50-200 GeV. Normalize 50-90 GeV and fit for the width in the high MT region 90-200 GeV. The tail region is sensitive to the width of the Breit Wigner line-shape. IMFP2008 - Day 2 February 5, 2008 Rick Field – Florida/CDF/CMS Page 14 There are more u-quarks than d-quarks at high x in the proton and hence the W+ (W-) is boosted in the direction of the incoming proton (antiproton). Measuring the W± asymmetry constrains the PDF’s! u p d u e+ W+ d u u xG(x,Q2) W Production Charge Asymmetry Q2 = 100 GeV2 MRST2004NLO u d p 10-3 e W- 10-2 10-1 1 W+ ds / dyW ds / dyW A( yW ) ds / dyW ds / dyW antiproton proton IMFP2008 - Day 2 February 5, 2008 Rick Field – Florida/CDF/CMS y Page 15 x W Production Charge Asymmetry Since the longitudinal momentum of the neutrino, pL(), is not known the W rapidity cannot be reconstructed. So previously one looked at the the electron charge asymmetry. The V-A structure of the W+ (W-) decay favors a backward e+ (forward e-) which “dilutes” the W charge asymmetry! since IMFP2006 New CDF measurement performed in W→e channel. pL() is determined by constraining MW = 80.4 GeV leaving two possible yW solutions. Each solution receives a probability weight according to the V-A decay structure and the W crosssection, s(yW). The process is iterated since s(yW) depends on the asymmetry. IMFP2008 - Day 2 February 5, 2008 Rick Field – Florida/CDF/CMS Page 16 W + g Cross Sections (CDF) IMFP2006 ET(g) > 7 GeV R(lg) > 0.7 s(W+g)*BR(W->l) IMFP2008 - Day 2 February 5, 2008 CDF (pb) NLO (pb) 19.71.7(stat)2.0(sys)1.1(lum) 19.31.4 Rick Field – Florida/CDF/CMS Page 17 W + g Cross Sections (CDF) since IMFP2006 ET(g) > 7 GeV R(lg) > 0.7 s(W+g)*BR(W->l) IMFP2008 - Day 2 February 5, 2008 CDF (pb) NLO (pb) 18.03±0.65(stat)±2.55(sys) ±1.05(lum) 19.71.7(stat)2.0(sys)1.1(lum) 19.31.4 Rick Field – Florida/CDF/CMS Page 18 Z + g Cross Sections (CDF) IMFP2006 Note: s(Wg)/s(Zg) ≈ 4 while s(W)/s(Z) ≈ 11 ET(g) > 7 GeV R(lg) > 0.7 s(Z+g)*BR(Z->ll) IMFP2008 - Day 2 February 5, 2008 CDF (pb) NLO (pb) 5.30.6(stat)0.3(sys)0.3(lum) 5.40.3 Rick Field – Florida/CDF/CMS Page 19 Z + g Cross Sections (CDF) since IMFP2006 390 events ET(g) > 7 GeV R(lg) > 0.7 Meeg > 40 GeV/c2 s(Z+g)*BR(Z->ee) IMFP2008 - Day 2 February 5, 2008 CDF (pb) NLO (pb) 4.90.3(stat)0.3(sys)0.3(lum) 4.70.4 Rick Field – Florida/CDF/CMS Page 20 The W+W Cross-Section IMFP2006 Campbell & Ellis 1999 pb-1 CDF (pb) NLO (pb) s(WW) CDF 184 14.6+5.8(stat)-5.1(stat)1.8(sys)0.9(lum) 12.40.8 s(WW) DØ 240 13.8+4.3(stat)-3.8(stat)1.2(sys)0.9(lum) 12.40.8 IMFP2008 - Day 2 February 5, 2008 Rick Field – Florida/CDF/CMS Page 21 The W+W Cross-Section (CDF) IMFP2006 WW→dileptons + MET Two leptons pT > 20 GeV/c. Z veto. MET > 20 GeV. Zero jets with ET>15 GeV and |h|<2.5. We are beginning to study the details of 95 events with Observe 37.2 background! Di-Boson production at the Tevatron! s(WW) L CDF (pb) NLO (pb) 825 pb-1 13.72.3(stat)1.6(sys)1.2(lum) 12.40.8 Missing ET! IMFP2008 - Day 2 February 5, 2008 Lepton-Pair Mass! Rick Field – Florida/CDF/CMS ET Sum! Page 22 WW+WZ Cross-Section since IMFP2006 NLO Theory σWW × Br(W→l, W→jj) = 12.4 pb × 0.146 = 1.81 pb σWZ × Br(W→l, Z→jj) = 3.96 pb × 0.07 = 0.28 pb s(WW+WZ)×BR(lvjj) IMFP2008 - Day 2 February 5, 2008 CDF (pb) NLO (pb) 1.47 ± 0.77(stat) ± 0.38(sys) 2.1 ± 0.2 pb Rick Field – Florida/CDF/CMS Page 23 The Z+W, Z+Z Cross Sections IMFP2006 W+Z → trileptons + MET Observe 2 events with a background of 0.9±0.2! Upper Limits W+Z, Z+Z Limit (pb) NLO (pb) CDF (194 pb-1) sum < 15.2 (95% CL) 5.00.4 DØ (300 pb-1) W+Z < 13.3 (95% CL) 3.70.1 CDF (825 pb-1) W+Z < 6.34 (95% CL) 3.70.1 IMFP2008 - Day 2 February 5, 2008 Rick Field – Florida/CDF/CMS Page 24 The W+Z Cross Section since IMFP2006 Strategy Search for events with 3 leptons and missing energy. Small cross-section but very clean signal. Anomalous cross-section sensitive to non SM contributions. 3.0 σ significance! s(W+Z) IMFP2008 - Day 2 February 5, 2008 L CDF (pb) NLO (pb) 1.9 fb-1 4.3±1.3(stat) ±0.2(sys) ±0.3(lum) 3.70.3 Rick Field – Florida/CDF/CMS Page 25 The Z+Z Cross Section since IMFP2006 Strategy: Search for events with either 4 leptons 2 leptons and significant missing ET. Calculate a Prob(WW) or Prob(ZZ) based on event kinematics and LO cross section. Construct a likelihood ratio. Fit to extract the ll signal. or ZZ ZZdecaying decayinginto into2 4 leptons leptons+ MET 3.0 σ significance! s(Z+Z) IMFP2008 - Day 2 February 5, 2008 L CDF (pb) NLO (pb) 1.9 fb-1 0.75+0.71-0.54 1.4±0.1 Rick Field – Florida/CDF/CMS Page 26 Higgs → W+W We are within a factor of two of the standard model Higgs (160 GeV) → WW! IMFP2008 - Day 2 February 5, 2008 since IMFP2006 Rick Field – Florida/CDF/CMS Page 27 Heavy Quark Production at the Tevatron with 1 fb-1 Total inelastic stot ~ 100 mb which is 103-104 larger than the cross section for ~1.4 x 1014 ~1 x 1011 ~6 x 106 ~6 x 105 ~14,000 ~5,000 D-meson or a B-meson. However there are lots of heavy quark events in 1 fb-1! Want to study the production of charmed mesons and baryons: D+, D0, Ds , lc , cc , Xc, etc. Want to studey the production of B-mesons and baryons: Bu , Bd , Bs , Bc , lb , Xb, etc. Two Heavy Quark Triggers at CDF: • For semileptonic decays we trigger on m and e. • For hadronic decays we trigger on one or more displaced tracks (i.e. large impact parameter). CDF-SVT IMFP2008 - Day 2 February 5, 2008 Rick Field – Florida/CDF/CMS Page 28 B-Baryon Observations (CDF) since IMFP2006 The Tevatron is excellent at producing particles containing and c quarks (Bu, Bd, Bs, Bc, Sb, Xb,b) b Xb Sb bc IMFP2008 - Day 2 February 5, 2008 Rick Field – Florida/CDF/CMS Page 29 Top Decay Channels mt>mW+mb so dominant decay tWb. The top decays before it hadronizes. B(W qq) ~ 67%. B(W l) ~ 11% l = e, m, t. dilepton lepton + jets all hadronic IMFP2008 - Day 2 February 5, 2008 Rick Field – Florida/CDF/CMS BR ~5% ~30% ~65% background low moderate high Page 30 Dilepton Channel (CDF) Selection: • • • • • 2 leptons ET > 20 GeV with opposite sign. Backgrounds: • Physics: Drell-Yan, WW/WZ/ZZ, Z >=2 jets ET > 15 GeV. tt Missing ET > 25 GeV (and away from any jet). • Instrumental: fake lepton HT=pTlep+ETjet+MET > 200 GeV. Z rejection. since IMFP2006 IMFP2006 84 events 65 events 20 events background s(tt)== 6.16 8.3 ±±1.5 (stat) ±± 1.00.72 (syst) + 0.5 (lumi) pb pb s(tt) 1.05 (stat) (syst) + 0.37 (lumi) IMFP2008 - Day 2 February 5, 2008 Rick Field – Florida/CDF/CMS Page 31 Lepton+Jets Channel (CDF) Require b-jet to be tagged for discrimination. b-Tagging 1 b tag IMFP2006 ~70 events HT>200GeV Tagging efficiency for b jets~50% for c jets~10% for light q jets < 0.1% 2 b tags ~180 events ~150 events ~45 events Small background! 2.0 s(tt) s(tt)== 8.2 8.8±±0.6 0.5 0.8(stat) (stat)±±1.1 0.8 1.2(syst) (sys) (sys)±± pb 0.5 0.5(lum) (lum) pb s (tt ) pb 8.81.2 (stat) 1.1 1.3 (syst)pb IMFP2008 - Day 2 February 5, 2008 Rick Field – Florida/CDF/CMS Page 32 Tevatron Top-Pair Cross Section since IMFP2006 CDF Run 2 Preliminary Theory 0.7 s (tt ) 6.70.9 pb Bonciani et al., Nucl. Phys. B529, 424 (1998) Kidonakis and Vogt, Phys. Rev. D68, 114014 (2003) IMFP2008 - Day 2 February 5, 2008 Rick Field – Florida/CDF/CMS Page 33 Top Quark Mass since IMFP2006 Leptons+Jets Dilepton Channel Channel Mt=170.4 ± 3.1(stat) ± 3.0(sys)GeV/c2 IMFP2008 - Day 2 February 5, 2008 Rick Field – Florida/CDF/CMS Page 34 Top Cross-Section vs Mass Tevatron Summer 2005 CDF Winter 2006 CDF combined Cacciari, Mangano, et al., hep-ph/0303085 IMFP2008 - Day 2 February 5, 2008 Rick Field – Florida/CDF/CMS Page 35 Constraining the Higgs Mass Top quark mass is a fundamental parameter of SM. Radiative corrections to SM predictions dominated by top mass. Top mass together with W mass places a constraint on Higgs mass! Tevatron Run I + LEP2 Summer 05 114 GeV Higgs very interesting for the Tevatron! IMFP2008 - Day 2 February 5, 2008 Rick Field – Florida/CDF/CMS Page 36 Other Sources of Top Quarks Strongly Produced tt Pairs Dominant production mode sNLO+NLL = 6.7 1.2 pb Relatively clean signature Discovery in 1995 g ~15% g ElectroWeak Production: Single Top Larger background Smaller cross section s ≈ 2 pb Not yet observed! IMFP2008 - Day 2 February 5, 2008 Rick Field – Florida/CDF/CMS q ~85% t t q Page 38 Single Top Production s-channel qq W * tb tW associated production t-channel bg tW qb q ' t (mtop=175 GeV/c2) s-channel t-channel Associated tW Tevatron sNLO 0.88 0.11 pb 1.98 0.25 pb ~ 0.1 pb LHC sNLO 10.6 1.1 pb 247 25 pb 62+17 -4 pb CDF < 18 pb < 13 pb D0 < 17 pb < 22 pb Run I 95% C.L. < 14 pb B.W. Harris et al.:Phys.Rev.D66,054024 Z.Sullivan Phys.Rev.D70:114012 IMFP2008 - Day 2 February 5, 2008 Rick Field – Florida/CDF/CMS Combine (s+t) T.Tait: hep-ph/9909352 Belyaev,Boos: hep-ph/0003260 Page 39 Single Top at the Tevatron IMFP2006 95% C.L. limits on single top cross-section Channel CDF (696 pb-1) DØ (370 pb-1) Combined 3.4 pb (2.9 pb) s-channel 3.2 pb (0.9 pb) 5.0 pb t-channel 3.1 pb (2 pb) 4.4 pb The current CDF and DØ analyses not only provide drastically improved limits on the single top cross-section, but set all necessary tools and methods toward a possible discovery with a larger data sample! Both collaborations are aggressively working on improving the results! Theory! Single Top Discovery is Possible in Run 2 !!!! - R. Field (IMFP2006) IMFP2008 - Day 2 February 5, 2008 Rick Field – Florida/CDF/CMS Page 40 Single Top Production since IMFP2006 Single Top Signal! DØ Combination 3.6s! 3.4s! Expected sensitivity: 2.1s ss+t= 4.9 ±1.4 pb ss= 1.0, st =4.0 pb PRL 98 18102 (2007) IMFP2008 - Day 2 February 5, 2008 First direct measurement of Vtb 0.68 <|Vtb|< 1 @ 95%CL or |Vtb| = 1.3 ± 0.2 Rick Field – Florida/CDF/CMS Page 41 Single Top Production since IMFP2006 3.1s! ss+t= 2.7 ± 1.2 pb ss= 1.1, st =1.3 pb Expected sensitivity: 2.9s Observed significance: 2.7s IMFP2008 - Day 2 February 5, 2008 ss+t= 3.0 ± 1.2 pb ss= 1.1, st =1.9 pb Expected sensitivity: 3.0s Rick Field – Florida/CDF/CMS Page 42 Measurement of |Vtb| (CDF) Using the Matrix Element cross section measurement, CDF determines |Vtb| assuming |Vtb| >> |Vts|, |Vtd|! CDF Run II Preliminary L=1.5 fb-1 s-channel t-channel |Vtb|= 1.02 ± 0.18 (exp) ± 0.07(thy) DØ |Vtb|>0.68, |Vtb| = 1.3 ±0.2 IMFP2008 - Day 2 February 5, 2008 Z. Sullivan, Phys.Rev. D70 (2004) 114012 Rick Field – Florida/CDF/CMS Page 43 Single Top Candidate Event t-channel single top production has a kinematic peculiarity. Distinct asymmetry in lepton charge Q times the pseudo-rapidity of the untagged jet! Central Electron Candidate Charge: u -1, Eta=-0.72d MET=41.6 GeV t-channel single top! EPD > 0.9 Jet1: Et=46.7 GeV Eta=-0.6 b-tag=1 Jet2: Et=16.6 GeV Eta=-2.9 b-tag=0 Q×h = 2.9 (t-channel signature) EPD=0.95 CDF Run: 211883, Event: 1911511 Jet1 Lepton Jet2 IMFP2008 - Day 2 February 5, 2008 Rick Field – Florida/CDF/CMS Page 44 Single Top at the Tevatron since IMFP2006 Single top cross-section measurements! Channel Theory CDF (1.5 fb-1) DØ (0.9 fb-1) Combined 2.9 pb 3.0 ± 1.2 pb 4.9 ± 1.4 pb s-channel 0.9 pb ≈ 1.1 pb ≈ 1.0 pb t-channel 2.0 pb ≈ 1.9 pb ≈ 4.0 pb Single top has (almost) been seen at the Tevatron at the expected rate! If you think 3.5s is enough to claim discovery? IMFP2008 - Day 2 February 5, 2008 Rick Field – Florida/CDF/CMS Page 45 Top-AntiTop Resonances CDF Run 1 Excess is reduced! Phys.Rev.Lett. 85, 2062 (2000) CDF observed an intriguing excess of events with top-antitop invariant mass around 500 GeV! IMFP2008 - Day 2 February 5, 2008 Rick Field – Florida/CDF/CMS Page 46 Top-AntiTop Resonances The excess has disappeared! since IMFP2006 Excess is gone! IMFP2008 - Day 2 February 5, 2008 Rick Field – Florida/CDF/CMS Page 47 Tevatron Measurements Jets b-quarks We are getting very close to the Higgs and/or new physics! W Z W+g Single top Z+g W+W tt W+Z Z+Z IMFP2008 - Day 2 February 5, 2008 Rick Field – Florida/CDF/CMS Page 48