Electroweak Physics Results at CDF Giulia Manca (University of Liverpool) for the CDF collaboration XXXIX th Rencontres de Moriond (EW), La Thuile (Italy), th March 2004

Giulia Manca, Moriond(EWK), 21-8 March 2004 Outline Tevatron and CDF Tevatron and CDF Electroweak physics at the Tevatron: Electroweak physics at the Tevatron:  Large numbers of W bosons  High mass Z/  * events  Sensitive to u & d quarks W and Z Cross section measurements(e, ,  ) W and Z Cross section measurements(e, ,  ) DiBoson production DiBoson production Conclusions and future prospects Conclusions and future prospects

Giulia Manca, Moriond(EWK), 21-8 March 2004 The Tevatron: Run II The Tevatron: Run II Oct Jan Apr Jul Oct Jan Apr Jul Oct Jan Total Luminosity (pb -1 ) Delivered To Tape Store Number CDF Run I 200 pb pb -1 TEVATRON TEVATRON performance improved : L del ~ 400 pb -1 CDF CDF:  E CM = 1.96 TeV  data taking efficiency > 85% ~350 pb − ¹  on tape L ~350 pb − ¹ Physics Physics Analyses:  Between 64 and 200 pb -1 taken Mar 2002 – Sep 2003   L ~ 6% (from  inel )

Giulia Manca, Moriond(EWK), 21-8 March 2004 The CDF-II detector Silicon Tracking Detectors Central Drift Chambers (COT) Solenoid Coil EM Calorimeter Hadronic Calorimeter Muon Drift Chambers Muon Scintillator Counters Steel Shielding polar angle    = 1.0  = 2.8  = 2.0 Giulia Manca, Moriond(EWK), 21-8 March 2004

The CDF-II detector Plug Calorimeter COT Muon Chambers Silicon

Giulia Manca, Moriond(EWK), 21-8 March 2004 EW Physics Roadmap W,Z cross sections e, ,  (central and forward) Lepton universality  (W)Width DiBoson Cross Sections A FB Z Asymmetry DiBoson couplings Test new interactions (anomalous couplings) Test new physics: high mass resonances W mass SM Higgs Mass Constraint Giulia Manca, Moriond(EWK), 21-8 March 2004

W, Z events selection Z: Z:  two electrons  high Pt  isolated  central or forward(e) W: W:  one lepton (e,  or   high Pt  isolated  central or forward(e)  large E T Z0+-Z0+-Z0+-Z0+- or  one muon  high Pt  isolated  central  2nd track  high Pt  isolated W  e W  e Z0+-Z0+-Z0+-Z0+-

Giulia Manca, Moriond(EWK), 21-8 March 2004 Inclusive W cross sections e E T (GeV) μ M T (GeV/c 2 ) - QCD, - Z  ℓ + ℓ −, - W , - cosmic (μ channel) Candidate events in 72pb -1 Estimatedbackground Acceptance x efficiency W  μ W  μ 31,722 (10.6 ± 0.4)% (14.39 ± 0.32)% W  e W  e 37,574 ( 4.4 ± 0.8)% (17.94 ± 0.35)% Giulia Manca, Moriond(EWK), 21-8 March 2004  electron    1.1

Giulia Manca, Moriond(EWK), 21-8 March 2004 Candidate events in 64 pb -1 EstimatedbackgroundAcceptance x efficiency W  e W  e 10,461 ( 8.7± 2.4)% (5.2 ± 0.2)% QCD, QCD, Z  ℓ + ℓ −, Z  ℓ + ℓ −, W , W , W  e in the plug Major systematics : PDFs, Amount of material in the simulation, Plug E T scale, Recoil modeling M T (GeV/c 2 )  ·BR(W  e ) =  stat  sys  lum nb electron E T (GeV) 1.1<  electron    2.8 W  e (MC) Sum

Giulia Manca, Moriond(EWK), 21-8 March 2004 Inclusive Z cross sections  2 nd e)   2.8 Number of candidates in 72pb -1 acceptance x efficiency Z/  *  e + e − CC 1730 Z/  *  e + e − CP 2512 Z/  *  μ+ μ− 1785 (10.18 ± 0.28)% 66 < m( ℓ ℓ )/GeVc -2 < 116 For 66 < m( ℓ ℓ )/GeVc -2 < 116 (22.74 ± 0.48)% Extended coverage in the forward   2.8 Extended coverage in the forward   2.8 Central Central (CC) + Central Plug (CP) Small backgrounds : Small backgrounds : QCD, Z/W  , cosmics (μ) < 1.5% Mee(GeV/c 2 ) μ e  1 st e)   1.0   1.0

Giulia Manca, Moriond(EWK), 21-8 March 2004 W   and Z   h +  ℓ − Signals Tau reconstruction: Tau reconstruction:  Count tracks in 10 o  - cone and veto tracks in 30 o isolation cone  Reconstruct   candidates in Shower Max detector  Combined mass < m(tau) Tau selection : Tau selection :  |  | < 1.0  E T > 25 GeV Z   h +  ℓ  − : first look ! Z   h +  ℓ  − : first look ! M(e+  +E T ) (GeV) W   : pb -1 W   : 2345 in ~72 pb % Background ~ 26 % (dominated QCD)  ·BR(W  ) = 2.62  0.07 stat  0.21 sys  0.16 lum nb Giulia Manca, Moriond(EWK), 21-8 March 2004

Summary of Cross sections (e +  )  Assuming lepton universality(correlated systematics accounted for )  ·BR(W  ℓ ) = 2777  10 stat  52 sys  167 lum pb  ·BR(Z  ℓℓ) =  3.3 stat  4.3 sys  15.3 lum pb NNLO theory curves (MRST 2002) Giulia Manca, Moriond(EWK), 21-8 March 2004

Extraction of  W  CDF + DØ  (pp  Z)  (W)  (Z  ℓℓ )  (pp  W)  (W  ℓ )  (Z) R R = Theoreticalprediction PDG combined Exp Measure Current World Ave: 2092 ± 40 MeV LEP direct measurement : 2150 ± 91 MeV Extract CDF(e +  L=72pb -1 D0(e) L=42pb -1 R  0.15 stat  0.13 sys  0.15 stat  0.13 sys ‡  0.35 stat  0.49 sys  0.35 stat  0.49 sys ‡ BR  W  ℓ ℓ )    (W) (2071  40) MeV (2187  128) MeV ℓ ℓ Using the NNLO calculation of  (W  ℓ ℓ ) : ‡ : ± 0.05 (J.Stirling)

Giulia Manca, Moriond(EWK), 21-8 March 2004 R g 2 R μ g 2 μ U U = R g 2 R e g 2 e = =  Lepton Universality W  e W   From the measurements of the W  e and W   cross sections : 0.99  0.04 stat  0.07 sys 0.99  0.04 stat  0.07 sys BR(W  ) BR(W  e ) = = 0.99  0.02 stat  0.04 sys gggg gegegege  g g μ g g e =  Calculating R separately for e and μ channels: gggg gegegege

Giulia Manca, Moriond(EWK), 21-8 March 2004 Forward-backward asymmetry Z/  *  p(q)p(q) ℓ+ℓ+ℓ+ℓ+ ℓ-ℓ-ℓ-ℓ candidates in ~ 72 pb -1 Unique at Tevatron (off Z pole) Unique at Tevatron (off Z pole) Directly probes V,A  sin 2  W,u, Directly probes V,A  sin 2  W,u, d couplings to Z d couplings to Z Sensitive to New Physics Sensitive to New Physics  Agreement with SM prediction.  1 st e)   1.0  2 nd e)   2.8

Giulia Manca, Moriond(EWK), 21-8 March 2004 Selection: 1 high-P T lepton (e,μ) 1 photon with: ℓ E T >7GeV,  R( , ℓ )>0.7 1 neutrino: large E T >25 GeV / Separate WW  vertex from (boring) lepton Bremsstrahlung Di-Boson production: W   M T (ℓ , ) /GeV pp  W  ℓ  ℓ probes EW boson self- coupling: direct consequence of SU(2)xU(1) gauge theory NEW PHYSICS, e.g. composite W modifies coupling M T (ℓ, ) /GeV

Giulia Manca, Moriond(EWK), 21-8 March 2004Candidate Events in 202 pb -1 estimatedbackground Wγ→ eνγ 131 (25 ± 6) % Wγ→ μνγ 128 (32 ± 5) % Di-Boson production: W  Data agree with SM expectation: NLO prediction (U. Baur):  ·BR  pp  W  ℓ  ℓ  = 19.3  1.3 pb ET()ET() ET()ET()  BR  W  ℓ  ℓ  =    BR  W  ℓ  ℓ  = 19.7  1.7 stat  2.0 sys  1.2 lum pb Next: extract WW  coupling from Photon E T spectrum N expected (L=202/pb) N(W+  MC) ± 2.08 ± 11.2 N(background) ± 0.46 ± Total SM ± 2.13 ± data259 Photon E T (GeV)

Giulia Manca, Moriond(EWK), 21-8 March 2004 Zγ Production pp  Z  ℓ + ℓ -  2 leptons: E T > 25 GeV ℓ 1 photon: E T > 7GeV,  R( , ℓ )>0.7 → New physics at Z  vertex? Non in SM !! e + μ N(Z+  MC) ± 3.76 N(background) 4.70 ± 1.34 Total ± 4.00 data69  ·BR  pp  Z   ℓℓ  = 5.4  0.4 pb NLO prediction(U. Baur): (LO + ET(γ) dependent k –factors):  BR  Z  ℓ + ℓ -   = 5.3  0.6 stat  0.3 sys  0.3 lum pb   BR  Z  ℓ + ℓ -   = 5.3  0.6 stat  0.3 sys  0.3 lum pb DATA AGREE WITH SM M(ℓℓ) (GeV/c2) M(ℓℓ  ) (GeV/c2)

Giulia Manca, Moriond(EWK), 21-8 March 2004 NLO prediction ‡ : Towards Higgs: WW Production  ·BR  pp  WW  ℓℓ  = pb ‡ J.M.Campbell, R.K.Ellis, Phys.Rev.D60:113006,1999, hep-ph/   BR  pp    WW  = = –3.6 (stat)  1.3 (sys)  0.3 (lum) pb p T W (GeV) d  /dp T W N(background) 2.34 ± 0.38 N(WW signal) 6.89 ± 1.53 data5 Motivation: Sensitive to WWγ and WWZ vertex Higgs discovery channel Anything new/unexpected? Selection : 2 OS leptons + E T + no jet with E T >15 GeV E T (GeV) / ℓ  (  , ℓ ) L = 126 pb -1 -

Giulia Manca, Moriond(EWK), 21-8 March 2004 Towards W Mass Use MC templates to fit to signal + background μ)CDF Run I ( μ) m W = ± 100(stat) ± 103(sys) MeV μ)CDF Run II for 250/pb estimate ( μ) : = X ± 55(stat) ± 80(sys) MeV Difficult measurement  Work in progress W → μν Z → μμ Data Simulation Total background Used to test the momentum scale (measured with J/  Data Simulation M   (GeV/c 2 )M   (  ) (GeV/c 2 ) direct extraction  (W) of  (W)

Giulia Manca, Moriond(EWK), 21-8 March 2004 Conclusions and Outlook Tevatron and CDF are running very well. Tevatron and CDF are running very well. We have measured cross sections for many electroweak processes and extracted the first electroweak parameters We have measured cross sections for many electroweak processes and extracted the first electroweak parameters all results (still) consistent with Standard Model. → all results (still) consistent with Standard Model. These measurements have set the basis for: These measurements have set the basis for:  Understanding of the detector  Understanding of the backgrounds  Lepton identification (e, mu, taus)  Many will soon become precision measurements sensitive to New Physics. Work well underway on CDFII first results on W-mass, W asymmetry, direct Γ(W) and boson-quark couplings … Work well underway on CDFII first results on W-mass, W asymmetry, direct Γ(W) and boson-quark couplings …