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Non-SM Higgs Searches at the TeVatron

Non-SM Higgs Searches at the TeVatron. Andy Hocker Fermi National Accelerator Laboratory for the CDF and D0 Collaborations ICHEP 2006. What we’re looking for. Minimal supersymmetric SM Higgs bosons The neutrals: h 0 , H 0 , A 0 ( =  0 ) The charged: H ±

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Non-SM Higgs Searches at the TeVatron

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  1. Non-SM Higgs Searches at the TeVatron Andy Hocker Fermi National Accelerator Laboratory for the CDF and D0 Collaborations ICHEP 2006

  2. What we’re looking for • Minimal supersymmetric SM Higgs bosons • The neutrals: h0, H0, A0 ( = 0) • The charged: H± • Doubly-charged Higgs bosons (H±±) • Part of Higgs triplet (0, H±, H±±) • Appear in L-R symmetric SM extensions • Can be light (~100 GeV), decay leptonically • Extremely low backgrounds • Fermiophobic Higgs bosons (0) • Can appear in “Type III” 2HDM • Fermion couplings suppressed, boson enhanced • Distinct signature of  decays via W triangles • …but no new results here… A. Hocker, ICHEP '06, Moscow

  3. MSSM 0 at the TeVatron • Large tan (favored by LEP2 data) enhances couplings to b-quarks,  • Most of 0 BR covered by bb (~90%),  • Production: • Main modes are • gg, bb0 (0bb hopeless, but not 0) • Associated production with b’s (both decays observable) A. Hocker, ICHEP '06, Moscow

  4. Experimental toolkit • Bottom-quark tagging • Exploit long lifetime of B hadrons • Requires precision tracking (Si microstrip detectors) with as much forward reach as possible • Tau ID • Hadronic decays • Isolated, narrow jets • Requires good tracking/EM calorimetry for charged/neutral pion reconstruction • Leptonic decays • Requires good EM cal, muon detector coverage • Large samples of Z’s/jets used to study efficiencies/fake rates A. Hocker, ICHEP '06, Moscow

  5. CDF and D0 in Run II Some highlights Si detectors (D0 just got some more!) Good central tracking Forward muon systems Trigger/DAQ CDF: forward calorimeter Data samples Over 1 fb-1 in the can Det/acc resumed operations in June, running well Results here range from 200-350 pb-1 A. Hocker, ICHEP '06, Moscow

  6. Searches for b0, bb0 (0bb) • Start from large multijet trigger sample • Require at least 3 jets w/ displaced secondary vertex • Form invariant mass of two leading b-jets, look for ≈bump • Shape and normalization of bgd determined from doubly-tagged data 260 pb-1 A. Hocker, ICHEP '06, Moscow

  7. b0, bb0 results 260 pb-1 • 95% CL upper limit on xsec vs. mA • Compare w/ predicted xsec for canonical MSSM benchmarks • Exclusions placed in mA, tan  plane A. Hocker, ICHEP '06, Moscow

  8. Searches for 0 • Select ehad, had, and (at D0) e events • Partially reconstruct Higgs via A. Hocker, ICHEP '06, Moscow

  9. 0 results (comb. w/ bb) Includes bbb(b) searches --- these are your “take-home” plots for the TeVatron A. Hocker, ICHEP '06, Moscow

  10. Just in from D0! • New search for (b)b0(b)b • Less signal + less background = competitive limit • Will be fruitful to combine • Updated search for (b)bbb • 0.9 fb-1 • New NN b-tagger • Still no signal, but ever-tighter limits • Too new for a nice mA-tan plot A. Hocker, ICHEP '06, Moscow

  11. Charged Higgs in top decays • Normally, ttWbWb • Well-def’d final states • If H± light enough, can replace one or both W’s • BR(t Hb) and H± decays depend on tan , mH (at tree level) • H±  • H± cs • H± t*b • H± W0 • Alters mix of tt final states A. Hocker, ICHEP '06, Moscow

  12. Indirect search for tH±b • Look at event yield in 4 tt final states: • lljj • ljj • ljjbj • ljjbb • Find joint prob to observe Ndata given expected yield for given mH, tan , etc. • Determine exclusion areas in mH vs. “X” plane A. Hocker, ICHEP '06, Moscow

  13. Charged Higgs Results New direct search for tHbb Look for anomalous production of ttlbj (almost pure tt) 4 expected from ttWbWb, 6 observed Limits on BR(t->Hb) assuming BR(H±) = 1 Indirect search from 200 pb-1 of tt in four final states mH/tan  exclusions for “no-mix” benchmark Other benchmarks explored as well Radiative SUSY corrections included! A. Hocker, ICHEP '06, Moscow

  14. Searches forH±±e,  • Same-sign lhad has significant background • H±± pair-produced, so require additional (loose) leptons • Counting experiment • < 1 SM event expected, zero observed A. Hocker, ICHEP '06, Moscow

  15. Conclusions • The MSSM provides the TeVatron with a real shot at a Higgs discovery • Light h0, decent xsec • Decays to b,  • Null results for 0 searches put the squeeze on the MSSM from the large tan  side A. Hocker, ICHEP '06, Moscow

  16. Backuppery A. Hocker, ICHEP '06, Moscow

  17. Evidence/discovery A. Hocker, ICHEP '06, Moscow

  18. Searches forH±±ee, e,  • Same-sign dilepton search in 3 sigma mass windows • Low backgrounds (limit ee search to > 100 GeV) No candidates, lower limits from 89-136 GeV set A. Hocker, ICHEP '06, Moscow

  19. Searches for quasi-stable H±± • H±± particles that do not decay in the detector • Look like highly-ionizing “muons” • Large dE/dx in tracking chamber • Basically, zero background… and zero observed A. Hocker, ICHEP '06, Moscow

  20. Searches for fermiophobic h0 Current results not competitive with LEP, but will be soon! Look for peaks in diphoton mass distribtution A. Hocker, ICHEP '06, Moscow

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