Searches for Non-Minimal Higgs Bosons

1. Searches for Non-Minimal Higgs Bosons Andre S. Turcot Brookhaven National Laboratory for the DØ Experiment at Fermilab With many thanks to: A. Haas, A. Kharchilava and G. Watts

2. Outline • A SUSY Higgs Primer • Searching for hbb • Doubling your fun with H++ • h  gg : Pushing beyond LEP

3. A SUSY Higgs Primer • Addition of a second scalar doublet results in 5 physical higgs bosons h, H, A, H+, H- • Standard Model Yukawa couplings modified: • hbb : sin(b - a) - tanb cos (b – a) • Hbb:cos(b - a) + tanb sin(b – a) • Abb: tan b • Two interesting cases arise for large tan b • CP Even states can flip-flop playing the role of SM higgs • M(A) >> M(Z)  cos(b - a) << 1 • M(A) ~ M(H), Hbb coupling  tan b • M(A) <~ M(Z)  cos(b - a) ~1 • M(A) ~ M(h), hbb coupling  tanb

4. SUSY Higgs Production • When tan b is large two of the three • Neutral Higgs bosons will have enhanced bb couplings CP-odd HiggsProduction CP-even HiggsProduction

5. SUSY Higgs: The RunII Angle • Much theoretical progress since RunII SUSY-Higgs Wkshp • Recent work indicates that the LO cross-sections are an underestimate by a factor ~3 (e.g. hep-ph/0204093) • Better understanding of NLO effects, scale dependencies • Theoretical bias towards expecting large tan  • b-τ Yukawa unification at the GUT scale → mt/mb ~ tan  ~ 50 • Since cross section scales astan2there will be a huge enhancement, O(1000) for motivated values • Leads to an interesting complementarity with LEP as Tevatron can probe high tan bregion of parameter space where small sin(b - a) and/or kinematics preclude hA, HA, Zh ZH production at LEP

6. Triggering on bb(h,H,A): • Multi-Level Trigger: • Level 1: Require 3 trigger towers of 5 GeV • Level 2: Require 3 jets of 8 GeV, HT > 50 GeV • Level 3: 3 Jets 15 GeV, 2 of 25 GeV, primary vtx within SMT • Rates at L ~ 60E30 are 280/100/6 Hz Done for all trigger components • Efficiencies relative to off-line selection are excellent e.g. for M=120 4 jets of 45, 35, 2x15 GeV (0.5 cone algorithm)

7. Tagging b-jets Secondary Vertex Tag Algorithm Extra Loose Operating Point Light j ~ 2% Many improvements in the works Improved Tracking Improved Alignment Improved Algorithms hbb This represents only the first “sketches” in the art of b-tagging

8. Quadruple b-tagged event

9. Search for bb(h,H,A): Leading Backgrounds: jjjj with multiple fakes bb jj with fake (8% ccjj) Zbb and bbbb are small Comparison of double b-tagged events with ≥4 jets to Monte Carlo The ALPGEN Monte Carlo describes the multi-jet heavy-flavor background very well. We have measured the normalization factor of data / MC : 1.14±0.02(stat.) ≥ 4 jets≥ 2 b-tags

10. Search for bb(h,H,A): Comparison of triple b-tagged events to expected background The background shape was extrapolated from double b-tagged data using a tag-rate-function derived on the full multi-jet data sample. Limits were set on the signal production, using simulated signal shapes, the normalized background, and the observed data. Excluded Signal ≥ 3 jets≥ 3 b-tags

11. Systematic Uncertainties Systematic Errors on Acceptance (%) Dominated by JES: Ongoing efforts to improve Systematic Errors on Backgrounds… Both b-id related and statistics 8-11% depending upon the optimized point

12. Search for bb(h,H,A): Constraints in the MSSM parameter space Limits will continue to improve with: More data Better b-tagging Better triggers Expect new results soon! 131 pb-1 of data Note Complementarity with LEP

13. Search for Doubly-Charged Higgs Many models predict the existence of Higgs bosons with twice the electric charge of other particles: • Left/Right Symmetric • Higgs Triplet • Little Higgs We search for decays of the doubly-charged Higgs into two like-signed muons. Assume a 100% branching ratio to muons when setting limits Coupling depends on L/Rhandedness Feynman diagram for the production of doubly-charged Higgs

14. Search for Doubly-Charged Higgs Comparisons of mass and Δφ distributions of the di-muon data to Monte Carlo Good agreement before requirment of Like Sign muons

15. Search for Doubly-Charged Higgs Comparisons of mass and Δφdistributions of the like-signed and isolated di-muon data to Monte Carlo No evidence of excess in like-sign isolated muons: 3 candidates vs 1.5 +/- 0.4 expected

16. Search for Doubly-Charged Higgs Confidence Limit set as a function of doubly-charged (left-handed) Higgs mass Set limits on the masses of doubly-charged Higgs bosons: mHL ++ > 118.4 GeV mHR ++ > 98.2 GeV 113 pb-1 On going efforts to improve Double the data set Include t t, WW channels

17. ` Search for Higgs→ γγ Some models predict an enhanced branching fraction of Higgs bosons to two photons: • Top-color Higgs • Fermio-phobic Higgs “Boso-phillic” at U of C Total bkgd. QCD Other Error on BG Reasonable agreement with expected background Di-photon Invariant mass

18. Search for Higgs → γγ No evidence of excess Set limits as a function of branching ratio assuming model dependent production cross-section Can extend LEP Reach With current data but mass limits will require more data Future Analyses will benefit from improved g ID

19. Conclusions has searched for non-minimal Higgs bosons • Data sets of 113 to 195 /pb studied • Results on hbb, H++ and h  gg • Unfortunately with no hint of a signal • Improvments to all channels in progress Attacking the key issues, b-tagging, JES • Stay tuned for more exciting results