DØ Higgs II Gordon Watts for the collaboration

2 Gordon Watts (UW Seattle) WIN’ /07/2003 Outline Channels H  WW * H  H ++ H --  +  +  -  - bbh  bbbb SM, TopColor, 4 th Generation SM, TopColor, Fermiphobic Higgs Triplet models; LR symmetric SUSY High tan  Current Status, Future Possibilities

3 Gordon Watts (UW Seattle) WIN’ /07/2003 H  WW * Production & Decay SM production primarily gluon fusion Analysis looks for decay to l l where l=e,  Lepton ID (High p T, medium p T ) Mass & angle cuts to eliminate Z &   Missing Transverse Energy Cap on Jet Activity (40 GeV) Cross Section Limit Actual Cuts for Each Channel listed on web pages Basic Analysis Cuts

4 Gordon Watts (UW Seattle) WIN’ /07/2003 H  WW * eeee  Lumi118 pb pb pb -1 Obs011 Expected1.1±0.80.9± ±0.12  BR (ee+e  ) < 0.45–2.8 pb  BR (  ) < 0.2–0.7 pb This will probably not be a SM search in Run II In mass range GeV/c 2

5 Gordon Watts (UW Seattle) WIN’ /07/2003 H  WW * Expectations Enhanced coupling for WW in top color and 4th generation models. Efficiency Currently x2 less than Higgs/SUSY workgroup result Mostly in Lepton ID Internal version of analysis has much better ID efficiency using more advanced tools SM Not at the Tevatron Non-SM

6 Gordon Watts (UW Seattle) WIN’ /07/2003 H  M H [GeV/c 2 ] Excluded SM Rate is too low to be observed at the Tevatron non-SM Models with suppressed fermion-Higgs coupling Some Universal ED models

7 Gordon Watts (UW Seattle) WIN’ /07/2003 H  Assume BR(H  ) = 1 Assume SM Higgs Production Cross-Section Photon ID, Apply Sliding Mass Window Cut Limit M  Data SM BG Sum DY QCD Luminosity = 51.8 pb -1  (M  ) ~ 2.5 GeV/c 2 Top Color Higgs Events/8 GeV DØ RunII Preliminary

8 Gordon Watts (UW Seattle) WIN’ /07/2003 H  Expectations Higgs/SUSY WGR With 50 pb -1 and BR=1 we expected a larger limit Top Color Higgs Working on bringing down the jet-photon misidentification rate

9 Gordon Watts (UW Seattle) WIN’ /07/2003 qq  Z /  *  H ++ H -- H ±± Production Higgs Triplet Model LR Symmetric versions Attractive as alternative to SUSY (CP, M ) Sharply falling  at the Tevatron

10 Gordon Watts (UW Seattle) WIN’ /07/2003 H ±± Production DØ look in the muon channel e,  (harder) possible Requires >=2 isolated  opening angle cuts (Z) 2  of like sign Requires >=2 isolated  opening angle cuts (Z) 2  of like sign Analysis Cuts (preselection)  = ( )±0.01 for M H = GeV/c 2

11 Gordon Watts (UW Seattle) WIN’ /07/2003 H ±± Results Luminosity = 107 pb -1 M(H ±± ) > 95 95% c.l. (right-handed) M(H ±± ) > % c.l. (left-handed) –world’s best limit Efficiency will improve with improved lepton ID Under Verification Cross section is sharply falling 80 GeV/c 2, 31 events 200 GeV/c 2, 0.48 events

12 Gordon Watts (UW Seattle) WIN’ /07/2003 SUSY Large tan  Search Promising SUSY channel at the Higgs/SUSY WS Since then Great deal of theory work NLO cross sections almost done Generation parameters better understood bh channel better developed ~tan  CP-odd Higgs Production

13 Gordon Watts (UW Seattle) WIN’ /07/2003 SUSY Large tan  Search Higgs WG DØ Expectations Jet ID b-tagging b-tag  3 dijet mass window cut HF Jet Corrections Coming soon to a conference near you … CompHEP + Pythia MC m h = 120 GeV/c 2

14 Gordon Watts (UW Seattle) WIN’ /07/2003 If we didn’t show this… Indirect Higgs Search… LEPEWWG Sum’03  M t < 2.5 GeV/c 2  M W < 40 MeV/c 2 Further Constrain the SM Currently 59 MeV/c 2 * Currently 5.1 GeV/c 2* *these are combined, Run II predictions are per experiment We have a long way to go…

15 Gordon Watts (UW Seattle) WIN’ /07/2003 Workshop Plots & Efficiencies The Public Higgs pages contain most plots and many more efficiency numbers: www-d0.fnal.gov  At Work  Physics Groups  Higgs  Public Documents. Look at the 2003 result links. Details Anyone here from DØ has access to our internal notes and should be able to answer further questions during this conference!

16 Gordon Watts (UW Seattle) WIN’ /07/2003 Conclusions Initial results for , WW *, and H ++ H -- shown. Analysis for hbb forthcoming. Other non-SM analyses being worked on –Charged Higgs, taus, etc. All results shown based on old version of analysis software –Results to be released for winter conferences should have improved understanding of detector. –Tracking and b-tagging in particular. Data Set Size –About 100 pb -1 of data shown. –Winter conferences should have over 200 pb -1 ! No detailed study of TeV Run II Reach –Run 2b Si cancellation strongly affects any analysis dependent on tracking (btagging, electron identification, muon identification, etc). –DØ is still studying how best to optimize the new situation. Stay tuned!