Tevatron Searches for Beyond-SM Higgs

1
Tevatron Searches for Beyond-SM Higgs

• Alexei Safonov
• (Texas AM University)
• For CDF D0 Collaborations

2
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 (mhlt135 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
3
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

4
MSSM Higgs Production
MSSM Higgs coupling to b, t tan ß

• Higgs decays
• bb (90)
• tt (5-13)

• gluon fusion

b-quark fusion
5
MSSM Higgsb(b)?bbb(b)
DØ

• Look for associated production with b(b)
  (suppress multi-jet bg)
• Require gt3 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 (mA90-150)
• Major syst uncertainties
• b-tagging (15)
• JES/resolution (9),
• signal simulation (5)
• trigger (9)
• luminosity (6.5)
• Bg estimation (3)

260 pb-1
6
MSSM Higgsb(b)?bbb(b)
DØ

• No evidence of signal
• Interpretation of the results mhmax and
  no-mixing scenarios with µlt0
• The search is sensitive down to tanß50-55 for
  m(A)90-150 GeV

260 pb-1
260 pb-1
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Neutral MSSM Higgs?tt
CDF

• Event selection
• Leptonic tau (tl t?lnn le,m)
• Hadronic tau (th t?hadrons n)
• Opposite charge of tl ,th , bg supression cuts
• Acceptance 1-2 (mA90-150 GeV)
• Dominant bg Z/g?tt
• Z/Higgs separation mvis(l,th,ET)

Before Ntrk and opposite charge cuts
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Neutral MSSM Higgs?tt
CDF

• 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
• PDFs (5.7)
• Luminosity measurement (6)
• Set limits by performing likelihood fit of
  mvis(l,th,ET) distribution

Example fit for mA140 GeV
9
Neutral MSSM Higgs?tt
CDF

• Interpret the results in mhmax and no-mixing
  scenarios with mlt0 and mgt0

• bb and tt Higgs decay channels are complementary
• Projections are based on the current analyses
  techniques
• A lot of improvements in the works

10
Neutral MSSM Higgs?tt
DØ

• Fresh off the press D0 result
• Include ethad,mthad, em
• 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

11
Charged MSSM Higgs
CDF

• Major decay modes
• H?tn
• H?cs
• H?tb?Wbb
• H?Wh?Wbb
• BRs depend on
• tan ß, m(H)
• Differ from W BRs

• Production

t ?bH (mH lt mt-mb)
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Charged MSSM Higgs
CDF

• 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 ß, and
  mH
• Lint 192 pb-1

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Charged MSSM Higgs
CDF
Final state bg events SM exp data
2l jets 2.70.7 11 13
l jets (1b) 20.32.5 54 49
l jets (2b) 0.940.17 10 8
l t jets 1.30.2 2 2
Consistent with the SM
No-mixing benchmark scenario
mhmax benchmark scenario
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Doubly Charged Higgs
CDF

• 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/mutau final states

H Lower Mass Limit H Lower Mass Limit H Lower Mass Limit H Lower Mass Limit
e m t
e 133 --- ---
m 115 136 ---
t 99 99 99
15
Doubly Charged Higgs
CDF
Z?ee removal not yet applied

• Selection
• Electron pTgt20 GeV
• Tau pTgt15 GeV
• LTC w/ seed track pTgt7 GeV
• Two event categories
• 3p channel etauLTC
• 4p channel etauLTCLTC
• Backgrounds
• Z/g(?ee)jets (most difficult)
• ZZ, WZ
• QCD (easy to remove)
• Others less significant

HTgt190 GeV
Note the similarity with a tri-lepton search
16
Doubly Charged Higgs
CDF

• Open the signal box
• No events found
• Expected 0.3 events
• No discovery, but can set an exclusion limit
• mHgt115 GeV new CDF result

H Lower Mass Limit H Lower Mass Limit H Lower Mass Limit H Lower Mass Limit
e m t
e 133 --- ---
m 115 136 ---
t 99 99 99
H Lower Mass Limit H Lower Mass Limit H Lower Mass Limit H Lower Mass Limit
e m t
e 133 --- ---
m 115 136 ---
t 115 ?? 99
MuonTau channel is nearly done. Box not opened,
but similar sensitivity
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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