6/15/2004Michael Kirby, Duke University1 Tevatron W/Z/  Results Part II Attack of the DiBosons 15th Topical Conference on Hadron Collider Physics Michael Kirby for the CDF and D0 Collaborations

6/15/2004Michael Kirby, Duke University2 Why study DiBoson production? Heavy Boson + photon, Two Heavy Bosons Natural extension of well understood and measured W and Z production Precise predictions available from many NLO calculations Small cross sections provide challenge Sensitive to non-Standard Model physics, internal structure of W and Z Places limits on Anomalous Trilinear Couplings Good confirmation of SU(2) L xU(1) Y structure of Electroweak sector

6/15/2004Michael Kirby, Duke University3 DiBoson Production at the Tevatron

6/15/2004Michael Kirby, Duke University4 The Tevatron at Fermilab Tevatron proton anti-proton collider at Fermilab –E Beam = 980 GeV –36x36 bunches with 396ns spacing Increased instantaneous Luminosity Typical: x cm –2 s -1 Record: ~7.83 x cm –2 s -1 Tevatron has delivered in total ~500 pb -1 Long term, by the end of FY09 Base goal: 4.4 fb -1 Design: 8.5 fb -1

6/15/2004Michael Kirby, Duke University5 Detector Integrated Luminosity Oct Jan Apr Jul Oct Jan Apr Jul Oct Jan Delivered To Tape Store Number CDF Run I 200 pb pb -1

6/15/2004Michael Kirby, Duke University6 The D0 Run II Detector

6/15/2004Michael Kirby, Duke University7 The CDF Run II Detector |  |= 1. |  |=2.

6/15/2004Michael Kirby, Duke University8 W  Production Includes the Triple Gauge Coupling –Anomalous terms ( , ) –SM (  =0, =0) Interference between ISR and TGC produces Radiation Amplitude Zero only in SU(2)xU(1) group After Detector Simulation LO MC Q(   -  l ) N EVENTS

6/15/2004Michael Kirby, Duke University9 Anomalous Couplings E T (  ) GeV  R(l,  ) SM In the E T  =0 limit, couplings equated with classical magnetic dipole and electric quadrupole

6/15/2004Michael Kirby, Duke University10 W  Event Selection Muon Photon Neutrino ETET pTpT ETET Electron Photon Neutrino ETET ETET ETET  Selection –Central Track assoc.  hits –P T > 20 GeV –CDF - |   | < 1.0 –D0 - |   | < 2.0 Electron Selection –EM Cluster > 25 GeV –Matched Track –Shower Shape Discrimination –CDF - |  e | < 1.1, 1.2<|  e | < 2.6 –D0 - |  e | < 1.1, 1.6<|  e | < 2.5 Missing Tranverse Energy –> 20 GeV for  candidates –> 25 GeV for e candidates

6/15/2004Michael Kirby, Duke University11 W  Event Selection Cont  Selection –Central Calorimeter –Shower profile discrimination –Calor. and Track Isolation –E T > 7 GeV (CDF) –E T > 8 GeV (D0)  -lepton separation –  R(l,  )>0.7    00 Shower Maximum Detector Pre-shower Detector CDF E t (  ) >7 GeV DØ E t (  ) >8 GeV  R( ,l)>0.7 |   |<1.1 Cal & trk-iso Background dominantly from W + jets –leading  0 fakes photon in jets Additional Bckgs - Z , W  , misreconstruction

6/15/2004Michael Kirby, Duke University12 W  Results Lum=202/pbLum=162/pb ETET > 7 GeV> 8 GeV N(W+  ) Signal ± ± 17.0 Tot Bkg94.7 ± ± 12.5 Total SM316.3 ± ± 21.4 Data Measured  (W  )  BR(W  l )= 19.9  2.7 (stat+sys)  1.1 (lumi) pb NLO Theory = 19.3  1.3 pb Measured  (W  )  BR(W  l )= 19.3  6.7 (stat +sys)  1.2 (lumi) pb NLO Theory = 16.4  0.4 pb

6/15/2004Michael Kirby, Duke University13 E T  Results CDF Run 2 Preliminary 202/pb D0 Run 2 Preliminary 162/pb

6/15/2004Michael Kirby, Duke University14  R(l,  ) Results D0 Run 2 Preliminary 162/pb

6/15/2004Michael Kirby, Duke University15 W  : l-E T Transverse Mass D0 Run 2 Preliminary 162/pb

6/15/2004Michael Kirby, Duke University16 Cluster Transverse Mass CDF Run 2 Preliminary 202/pb Greater sensitivity to Anomalous Couplings and RAZ in high CTM region

6/15/2004Michael Kirby, Duke University17 Z  Production No ZZ  Triple Gauge Coupling in Standard Model at tree level –no Radiation Amplitude Zero –Anomalous terms(h  i0, h Z i0 ) –SM (h  i0 =0, h Z i0 =0) Excellent cross check for W  production Anomalous terms can be related to the dipole and quadrupole moments Z Z l Z Z

6/15/2004Michael Kirby, Duke University18 Z  Event Selection Muon Photon Muon ETET pTpT Electron Photon Electron ETET ETET  Selection –Central Track –P T > 20 GeV –opposite charge –CDF - |   | < 1.0 Electron Selection –EM Cluster > 25 GeV –CDF - |  e | < 2.6 Invariant Mass > 40 GeV Photon selection –E T  > 7 GeV –  R(l,  )>0.7 ETET pTpT Background from Z + jets

6/15/2004Michael Kirby, Duke University19 Z  Results Lum=202/pb N(Z+g) Signal 65.8 ± 3.8 Tot Bkg4.7 ± 1.4 Total SM70.5 ± 4.0 Data70 Z+jet4.5 ± 1.3 FakeZ+  0.2 ± 0.15 Measured  (Z  )  BR(Z  ll) = 4.5  0.5 (stat + sys)  0.3 (lumi) pb NLO Theory = 4.5  0.3 pb (E T  > 7 GeV,  R(l,  )>0.7) Backgrounds Note:  (W  )/  (Z  ) ≈3 while  (W)/  (Z) ≈10

6/15/2004Michael Kirby, Duke University20 Z  Results CDF Run 2 Preliminary 202/pb

6/15/2004Michael Kirby, Duke University21 Z  Results CDF Run 2 Preliminary 202/pb

6/15/2004Michael Kirby, Duke University22 WW, WZ, and ZZ Production Complementary probe of Triple Gauge Coupling –higher Boson and Lepton P T indicates Anom. Coup. Small cross sections make for challenging measurement Study using leptonic decays of the W and Z Important foundation for Higgs searches

6/15/2004Michael Kirby, Duke University23 CDF: WW (Two approaches) Dileptons: l +,l - : identified e,  Reject 76<M ll <106 & E T sig <3.0 E T >25 No High Et jets Opposite sign & Isolation (Identified e,  )+Iso track Reject E T sig <5.5 in all M ll E T >25 Njets<=1 Opposite sign & Isolation High S/BIncreased acceptance Two complementary approaches  DY, Z   WZ/ZZ, Z   top dilepton  Fakes Missing E T Signifigance (  GeV)

6/15/2004Michael Kirby, Duke University24 CDF: WW cross section l+track e,  WW 16.3   1.3 Bkg 15.1   0.70 WW+Bkg 31.5   1.6 Data3917 NLO (Campbell & Ellis, 1999)  WW =12.5  0.8 pb e,  l+track

6/15/2004Michael Kirby, Duke University25 CDF: WW Beyond SM Anomalous TGC WWZ/WW  gg  H  WW 140<M H <180GeV/c 2 Jet: >15 GeV Cone 0.4

6/15/2004Michael Kirby, Duke University26 WW  e e or ZZ  ee ?

6/15/2004Michael Kirby, Duke University27 ZW, ZZ study in Run II Event selections –Four lepton events Signal: ZZ Background: Z/W+jets, multijet –Three lepton events Signal: ZZ, ZW Background: Z/W+jets, multijet –Two lepton events Signal: ZZ, ZW Background: WW, Drell Yan, Top, W+jets Select Z  ll

6/15/2004Michael Kirby, Duke University28 ZW, ZZ study in Run II Cross section upper limit consistent with SM prediction of 5.2 ± 0.4 pb 95% Conf Limit

6/15/2004Michael Kirby, Duke University29 The Next Steps Tevatron has excellent DiBoson production studies ongoing. Will measure limits on Anomalous Triple Gauge Couplings –W , Z , WW, ZW, and ZZ Establish baseline for other DiBoson production Already have WW searches for Higgs production and improving upon understanding of HW production (see Michael Gold’s talk on Thursday) Non-dilepton analyses are underway