Tevatron Searches for Beyond-SM Higgs Alexei Safonov (Texas A&M University) For CDF & D0 Collaborations

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 GeV) Several Higgses: h, H, H+/-, A Possible non-universality in coupling Production enhancement likely 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 ~tanb Higgs is mentioned in the title of my talk. What makes it so special in searches for new physics? Let’s recall some basics. What’s interesting about Higgs is that whatever that new physics is, it is very hard to not have a Higgs boson there Thus Higgs is what I would call a convenient target: we know it got to be out there and we know what it looks like. Moriond-QCD, March 21,2006 A. Safonov (Texas A&M)

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 3rd generation Moriond-QCD, March 21,2006 A. Safonov (Texas A&M)

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

MSSM Higgs+b(b)→bbb(b) DØ MSSM Higgs+b(b)→bbb(b) Look for associated production with b(b) (suppress multi-jet bg) Require >=3 b-tagged jets (sec. vtx) Form invariant mass of the two highest-ET jets – binned fit Data sample: ~260 pb-1 260 pb-1 b-tag rate estimated from data Acceptance ~0.3-1% (mA=90-150) Major syst uncertainties: b-tagging (15%) JES/resolution (9%), signal simulation (5%) trigger (9%) luminosity (6.5%) Bg estimation (3%) 260 pb-1 Moriond-QCD, March 21,2006 A. Safonov (Texas A&M)

MSSM Higgs+b(b)→bbb(b) 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 GeV 260 pb-1 260 pb-1 Moriond-QCD, March 21,2006 A. Safonov (Texas A&M)

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% (mA=90-150 GeV) Dominant bg: Z/g*→tt Z/Higgs separation: mvis(ℓ,th,ET) Before Ntrk and opposite charge cuts Reconstruction of th: Cone algorithm Energy from trks and p0’s Isolation veto (trk, p0) Hadronic system: mhad< 1.8 GeV Ntrk = 1,3 ; charge = ±1 Moriond-QCD, March 21,2006 A. Safonov (Texas A&M)

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 mA=140 GeV Moriond-QCD, March 21,2006 A. Safonov (Texas A&M)

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)

DØ Neutral MSSM Higgs→tt Fresh off the press D0 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)

CDF Charged MSSM Higgs Major decay modes: Production: 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 Production: t →bH+ (mH < mt-mb) Moriond-QCD, March 21,2006 A. Safonov (Texas A&M)

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 Check consistency of the final states with SM expectation Interpret for several MSSM scenarios, tan β, and mH Lint = 192 pb-1 Moriond-QCD, March 21,2006 A. Safonov (Texas A&M)

CDF Charged MSSM Higgs Consistent with the SM Final state bg events SM exp data 2ℓ + jets 2.7±0.7 11 13 ℓ+ jets (1b) 20.3±2.5 54 49 ℓ + jets (≥2b) 0.94±0.17 10 8 ℓ + t + jets 1.3±0.2 2 Consistent with the SM No-mixing benchmark scenario mhmax benchmark scenario Moriond-QCD, March 21,2006 A. Safonov (Texas A&M)

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 vR ~ 1010 GeV, mH±± ~ 100 GeV DY-like H++ pair production Constrained by the r parameter s(m = 100 GeV) = 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 H++ Lower Mass Limit e m t 133 --- 115 136 99 Moriond-QCD, March 21,2006 A. Safonov (Texas A&M)

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

CDF Doubly Charged Higgs H++ Lower Mass Limit e m t 133 --- 115 136 99 Open the signal box: No events found Expected ~0.3 events No discovery, but can set an exclusion limit mH++>115 GeV – new CDF result H++ Lower Mass Limit e m t 133 --- 115 136 99 H++ Lower Mass Limit e m t 133 --- 115 136 ?? 99 Muon+Tau channel is nearly done. Box not opened, but similar sensitivity Moriond-QCD, March 21,2006 A. Safonov (Texas A&M)

Summary and Outlook The Higgs boson is being hunted at the Tevatron Various scenarios and Higgs species D0 and CDF are competing, will soon start combining results Taus are in the game at both CDF and D0 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 Major improvements are better triggers, better identification efficiency and better background rejection Moriond-QCD, March 21,2006 A. Safonov (Texas A&M)