Tevatron Searches for BeyondSM Higgs Alexei Safonov Texas

Tevatron Searches for Beyond-SM Higgs Alexei Safonov (Texas A&M University) For CDF & D 0 Collaborations Moriond-QCD, March 21, 2006 A. Safonov (Texas A&M)

Higgs • Standard Model Higgs: – Higgs mechanism generates particles masses – Single physical scalar H, coupling ~mf • Higgs is unavoidable in most extensions of SM – Supersymmetry: • • Radiative EWSB (mh<135 Ge. V) Several Higgses: h, H, H+/-, A Possible non-universality in coupling Production enhancement likely ~tanb – Little(st) Higgs: • Three-scale model • Light Higgs h • Also A, H, H+/-, H++/-- – … • Compared to the zoo of SUSY final states and complicated phenomenology, Higgs is an “easy” target for searches Moriond-QCD, March 21, 2006 A. Safonov (Texas A&M) 2

Higgs Searches at the Tevatron • In this talk: – Neutral Higgs Searches • Multi-b final state (SUSY) • Di-tau final state – Charged Higgs • Analysis of top decay branching ratios – Doubly Charged Higgs (LR-sym. models) • Lepton Flavor Violation involving 3 rd generation Moriond-QCD, March 21, 2006 A. Safonov (Texas A&M) 3

MSSM Higgs Production MSSM Higgs coupling to b, t ~tan β Higgs decays: – bb (~90%) – tt (~5 -13%) gluon fusion Moriond-QCD, March 21, 2006 b-quark fusion A. Safonov (Texas A&M) 4

DØ MSSM Higgs+b(b)→bbb(b) • Look for associated production with b(b) (suppress multi-jet bg) 260 pb-1 – Require >=3 b-tagged jets (sec. vtx) • Form invariant mass of the two highest -ET jets – binned fit Data sample: ~260 pb-1 • b-tag rate estimated from data • Acceptance ~0. 3 -1% (m. A=90 -150) • Major syst uncertainties: – b-tagging (15%) – JES/resolution (9%), – signal simulation (5%) – trigger (9%) – luminosity (6. 5%) – Bg estimation (3%) Moriond-QCD, March 21, 2006 A. Safonov (Texas A&M) 260 pb-1 5

DØ MSSM Higgs+b(b)→bbb(b) • No evidence of signal • Interpretation of the results: mhmax and no-mixing scenarios with μ<0 • The search is sensitive down to tanβ~50 -55 for m(A)~90 -150 Ge. V 260 pb-1 Moriond-QCD, March 21, 2006 A. Safonov (Texas A&M) 6

CDF Neutral MSSM Higgs→tt • Event selection – Leptonic tau (tℓ : t→ℓnn; ℓ=e, m) – Hadronic tau (th : t→hadrons n) – Opposite charge of tℓ , th , bg supression cuts • Acceptance ~1 -2% (m. A=90 -150 Ge. V) • Dominant bg: Z/g*→tt • Z/Higgs separation: mvis(ℓ, th, ET) Reconstruction of th: Before Ntrk and opposite charge cuts Cone algorithm Energy from trks and p 0’s Isolation veto (trk, p 0) Hadronic system: mhad< 1. 8 Ge. V Ntrk = 1, 3 ; charge = ± 1 Moriond-QCD, March 21, 2006 A. Safonov (Texas A&M) 7

CDF Neutral MSSM Higgs→tt • Observed 487 ev, expect 496± 5. 4(stat) ± 27. 7(sys) ± 24. 8(lum) • Dominant systematic uncertainties: – Particle ID: th (3. 5%), e (1. 3%), m (4. 6%) – Jet→t mis-ID estimate (20%) 3% on total bg – PDF’s (5. 7%) – Luminosity measurement (6%) • Set limits by performing likelihood fit of mvis(ℓ, th, ET) distribution Example fit for m. A=140 Ge. V Moriond-QCD, March 21, 2006 A. Safonov (Texas A&M) 8

CDF Neutral MSSM Higgs→tt • Interpret the results in mhmax and no-mixing scenarios with m<0 and m>0 • bb and tt Higgs decay channels are complementary • Projections are based on the current analyses techniques • A lot of improvements in the works Moriond-QCD, March 21, 2006 A. Safonov (Texas A&M) 9

DØ Neutral MSSM Higgs→tt • Fresh off the press D 0 result: – Include e+thad, m+thad, e+m • NN for tau ID: 3 types of had taus • Fit invariant mass distribution and set limit • Combine with the result in bbb(b) channel • No signal, set limit • Lots more data to come • Taus become really important Moriond-QCD, March 21, 2006 A. Safonov (Texas A&M) 10

CDF Charged MSSM Higgs • Major decay modes: • Production: t →b. H+ (m. H < mt-mb) – H+→t+n – H+→cs – H+→t*b→W+bb – H+→W+h→W+bb • BR’s depend on: – tan β, m(H+) • Differ from W+ BR’s Moriond-QCD, March 21, 2006 A. Safonov (Texas A&M) 11

CDF Charged MSSM Higgs • Look at four tt final states: – di-lepton + jets – lepton + jets (=1 b-tag) – lepton + jets (≥ 2 b-tags) – lepton + tau + jets Moriond-QCD, March 21, 2006 • Check consistency of the final states with SM expectation • Interpret for several MSSM scenarios, tan β, and m. H • Lint = 192 pb-1 A. Safonov (Texas A&M) 12

CDF Charged MSSM Higgs Final state bg events SM exp dat a 2ℓ + jets 2. 7± 0. 7 11 13 ℓ+ jets (1 b) 20. 3± 2. 5 54 49 ℓ + jets (≥ 2 b) 0. 94± 0. 1 7 10 8 No-mixing benchmark scenario 2 2 ℓ + t + jets 1. 3± 0. 2 Moriond-QCD, March 21, 2006 Consistent with the SM mhmax benchmark scenario A. Safonov (Texas A&M) 13

CDF Doubly Charged Higgs • Little Higgs and L/R symmetric models (incl. SUSY) – Elegant solution for massive neutrinos via see-saw mechanism – H++ can be light • v. R ~ 1010 Ge. V, m. H±± ~ 100 Ge. V – DY-like H++ pair production • Constrained by the r parameter – s(m = 100 Ge. V) = 120 fb (1000 times less than Z tt) – Published results in e/mu channels supersede LEP – Tau decays: start with e/mu+tau final states Moriond-QCD, March 21, 2006 H++ Lower Mass Limit e m t e 133 ----115 136 --m 99 99 99 t A. Safonov (Texas A&M) 14

CDF Doubly Charged Higgs Z ee removal not yet applied • Selection: – Electron p. T>20 Ge. V – Tau p. T>15 Ge. V – LTC w/ seed track p. T>7 Ge. V • Two event categories: HT>190 Ge. V – 3 p channel: e+tau+LTC – 4 p channel: e+tau+LTC • Backgrounds: – – Z/g*( ee)+jets (most difficult) ZZ, WZ QCD (easy to remove) Others less significant Note the similarity with a tri-lepton search Moriond-QCD, March 21, 2006 A. Safonov (Texas A&M) 15

CDF Doubly Charged Higgs • Open the signal box: – No events found – Expected ~0. 3 events • No discovery, but can set an exclusion limit • m. H++>115 Ge. V – new CDF result H++ Lower Mass Limit e m t e 133 ----115 136 --m 99 ? ? 115 99 99 t Muon+Tau channel is nearly done. Box not opened, but similar sensitivity Moriond-QCD, March 21, 2006 A. Safonov (Texas A&M) 16

Summary and Outlook • The Higgs boson is being hunted at the Tevatron – Various scenarios and Higgs species – D 0 and CDF are competing, will soon start combining results • Taus are in the game at both CDF and D 0 – Very important for Higgs in SUSY – May well turn out to be very useful for SM Higgs • No smoking gun with the analyzed data, but already 2 -5 times more data on tape • With some luck, you may hear from us before LHC Moriond-QCD, March 21, 2006 A. Safonov (Texas A&M) 17