1. Gregorio Bernardi / LPNHE-Paris Gregorio Bernardi, LPNHE-Paris VI & VII Status of Higgs Searches @ DØ Publications Publications to come, p17 prel. SM Higgs Searches at High mass Combined D0 and CDF+D0 results. Susy Higgs status Future plans

2. Gregorio Bernardi / LPNHE-Paris 2 Publications ‘03 : 1 H ++ ‘04 : 2 WH, Zb/Zj (and WW x-section) ‘05 : 2 bbh, H  WW * ‘06: 4 so far (based on 260-350 pb -1 of data) h      (includes combination with hbb)  WH  WWW*  ZH   b b  Z + n jets x-section

3. Gregorio Bernardi / LPNHE-Paris 3 P14 Publications coming SM: WH (e,  ) (moriond) ZH  l + l - b b (ee,  ) (ICHEP) SM combination (ICHEP) Z  bb (x-section) (ICHEP) SUSY: bbh with h     - (ICHEP) Technicolor: e and  channels (ICHEP)

4. Gregorio Bernardi / LPNHE-Paris 4 P17 Preliminary Results SM: Z+jets Sherpa study (moriond) H  WW * (ee, e  (moriond)  (ICHEP) Updated SM combination (+ CDF) SUSY bbh with h  bb (ICHEP) In the works (cf Higgs p17 meeting tue/fri.) ZH  b b, ZH  l + l - b b (ee,  ) WH (e,  ) h   H + (direct, indirect)

5. Gregorio Bernardi / LPNHE-Paris 5 SM “Heavy” Higgs: H  WW*  l l Search strategy:  2 high P t leptons and missing E t  WW comes from spin 0 Higgs: leptons prefer to point in the same direction. But Higgs mass peak cannot be reconstructed due to the presence of 2   look for an excess CDF and DØ already published on 0.3-0.4 fb -1 H 4 th generation? W+W+ e+e+ W-W- e-e- n Updated DØ analysis: L ~ 950 pb -1 in H  WW*  ee and e  L ~ 930 pb -1 in H  WW*   Selection : Presection: lepton ID, trigger, opposite charge leptons Remove QCD and Z  l + l - : E T > 20 GeV Higgs Mass Dependent Cuts: Invariant Mass (M l+l- ); Min. Transverse Mass Sum of lepton p T l and E T (  p T l + E T ) Anti tt(bar) cut: H T =  P T jet < 100 GeV Spin correlation in WW pair:  (l,l) < 2.0 Major backgrounds: WW production, W + jet/  production

6. Gregorio Bernardi / LPNHE-Paris 6 H  WW* : final selection M H =160GeV (x10) selection s  ee ee

7. Gregorio Bernardi / LPNHE-Paris 7 SM only a factor 4 away We exclude 4 th generation models, for which m H =150-185 GeV Results for H  WW* Expected/Observed # of events for m H = 160 GeV (L ~ 950 pb -1 ):   If m H = 160 GeV,  ~ 2 higgs in our sample!

8. Gregorio Bernardi / LPNHE-Paris 8 Low BR, but channel important in the “ intermediate region ” 125-145 GeV Search for WH  WWW* (2 like-sign leptons) Event preselection: Same charge di-lepton from W ’ s (one from H  WW, the other from prompt W) Suppress SM backgrounds p T (lepton)> 15 GeV, |  | < 1.1/2.0

9. Gregorio Bernardi / LPNHE-Paris 9 Final Selection for WWW* Topological Likelihood discriminant, built on 3 variables per channel

10. Gregorio Bernardi / LPNHE-Paris 10 Exclusion limit for WWW* Events after Topological Likelihood discriminant Effect on global combination significant in the intermediate region (125-145 GeV) Being improved in p17 with ZH  ZWW and also with H  ZZ*

11. Gregorio Bernardi / LPNHE-Paris 11 With low statistics (0.3 fb -1 ), the cross-section factors Data/SM = ~ 15 at 115 GeV ~ 9 at 160 GeV With higs statistics (1 fb -1 ) Data/SM = ~ 5 at 160 GeV Based on our first experiences with Data, can cdf+dØ reach exclusion for a 115 GeV Higgs with 2 fb -1 of data, as early simulation studies were expecting ? Combined Higgs boson Search @ DØ New channel

12. Gregorio Bernardi / LPNHE-Paris 12 Expected Improvements @ DØ New b-tagging tool at DØ (bh) –Combines various variables from the track based b-tagging tools in a Neural Network, trained on Monte Carlo –Performance measured on data –Substantial improvement in performance over constituent input b-taggers –Increase of 33% in efficiency for a fixed fake rate of 0.5 % Jet energy resolution (recalibration + track-jet algorithm) Subtract expected energy deposition in cal Add the track momentum Add the energy of out-of-cone tracks Improve the jet energy resolution by ~20% Use improved calorimeter calibration Z  bb to calibrate b-jet response L1-cal Trigger (DØ Upgrade) –Important for difficult channels  efficiency improvement (ZH  bb, hbb) Addition of SMT Layer 0 (DØ Upgrade) –r@L1 = 2.7 cm  r@L0 = 1.6 cm  better impact parameter resolution -redundancy in pattern recongnition for higher luminosity reduce fake track –Keep performance if degradation of Layer 1 due to radiation damage  further b-tag improvement (~15%)  improvement on Higgs sensitivity

13. Gregorio Bernardi / LPNHE-Paris On the Horizon ✗ Will 6 times more lumi take our x-section factors at 115/160 GeV of ~15/9 down to 1?? Maybe.. with analyses improvements under work in CDF and DØ  Close ! Ingredients (DØ) Equiv Lumi gain (@115) Today with ~330 pb -1 -15 9 6.06.1 3.7 Combine DØ and CDF2.0 NN b-Tagger/L03.0 3.5 NN analysis selections1.7 2.7 2.8 Dijet-mass resolution1.5 2.2 Increased Acceptance1.2 2.0 2.5 New channels1.2 1.9 2.1 1.7Reduced Systematics1.2 1.2 1.5  At 160 GeV needs ~5 fb -1  At 115 GeV needs ~3 fb -1 Xsec Factor m H =115 GeV m H = 160 GeV Sensitivity Prospects extrapolated from 0.3 fb -1 results Lumi = 2.0 fb-1  95% CL exclusion for m H = 115-185 GeV with 8 fb -1 (assuming similar improvements at DØ and CDF)

14. Gregorio Bernardi / LPNHE-Paris Combination Procedure Combining Higgs boson Searches DØ uses the CLs (LEP) Method the CL S confidence interval is a normalization of CL S+B CL S+B = signal + bkgd hypothesis, CL B = bkgd only hypothesis CL S = CL S+B /CL B : CL S+B & CL B are defined using a “test statistic” Test statistic used is the Log-Likelihood Ratio (LLR=-2 ln Q) generated via Poisson statistics (Q=e -(s+b) (s+b) d /e -b b d ) s,b,d=sig.,bkd,data) Tevatron Higgs combination is done with both methods  they give results compatible within 10%. CDF uses a Bayesian approach

15. Gregorio Bernardi / LPNHE-Paris 15 Tevatron SM Higgs Combination m H Limit/SM (GeV) Exp. Obs. 115 7.6 10.4 130 10.1 10.6 160 5.0 3.9 180 7.5 5.8 Note: the combined result is essentially equivalent to one experiment with 1.3 fb -1, since both experiments have “complementary” statistics at low and high mass  we are indeed already close to the sensitivity required to exclude or “evidence” the higgs at the Tevatron All CDF and DØ results now combined for the first time 

16. Gregorio Bernardi / LPNHE-Paris 16 Low mass, use Z  bb MC: 83.3 GeV 13.0 GeV 4.4 sigma evidence based on about 300 pb -1 of data, shown at ICHEP. Rate consistent with SM production. After double b-tag and “shift” correction

17. Gregorio Bernardi / LPNHE-Paris 17 SUSY Higgs New channels released at ICHEP: bh  b tau tau  (3 evts vs 6.3 +- 0.6) Need to combine with bbb and h  tautau Note: p17 available or close for these channels btautau also getting prepared H + started, to be done with top group

18. Gregorio Bernardi / LPNHE-Paris 18 Manpower Issues Team work to provide best combination, we are strengthening p17 teams and form p20 teams. Enquiry sent around to the group, to find out about new students: 12 institutions have answered with new students  there won’t be one topic per student, rather teams of 1-3 student+1-2 postdoc per channel, and use different timescale (2 milestones per years). SM Channels: WH, ZH (nunu), ZH (l + l - ), WW, WWW, tau-channels. SUSY Channels: h  tautau, bbb, btautau, H + direct, H + indirect. BMSSM “higgs” H ++, TC, ….

19. Gregorio Bernardi / LPNHE-Paris Conclusions ✗ First time with essentially complete result All channels have been analyzed with ~0.3-1 fb -1 of data ✗ Full impact of systematics uncertainties is included ✗ Analyses are steadily improving due to optimization, already close to the Prospective reports Combined limit looks very promising Our outlook for the future looks very interesting ✗ LHC experiments will have to work hard to get the signal before Tevatron, if the Higgs is light (<130 GeV) ✗ But the Tevatron has insight also if it is close to 160 GeV and can exclude at 95%CL from 115 to 185 GeV. ✗ Barring accidents, the Tevatron could have evidence by 2009-2010, if it’s there… But we need to be fast and clever in analyzing  more efforts are needed, input of seniors is welcome !! Besides all analyzers, I would like to thank Suyong and Kazu for excellent collaboration, and welcome Sasha Khanov Summary