Non-SM Higgs Searches at the TeVatron

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Non-SM Higgs Searches at the TeVatron

• Andy Hocker
• Fermi National Accelerator Laboratory
• for the CDF and D0 Collaborations
• ICHEP 2006

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What were 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

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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 bs (both decays
  observable)

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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 Zs/jets used to study
  efficiencies/fake rates

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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
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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
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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

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Searches for ?0???

• Select ?e?had, ???had, and (at D0) ?e?? events
• Partially reconstruct Higgs via

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?0??? results (comb. w/ bb)
Includes bbb(b) searches --- these are your
take-home plots for the TeVatron
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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

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Charged Higgs in top decays

• Normally, tt?WbWb
• Well-defd final states
• If H light enough, can replace one or both Ws
• BR(t ?Hb) and H decays depend on tan ?, mH (at
  tree level)
• H ???
• H ?cs
• H ?tb
• H ?W?0
• Alters mix of tt final states

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Indirect search for t?Hb

• 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

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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-gtHb) 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!
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Searches forH?e?, ??

• Same-sign l?had has significant background
• H pair-produced, so require additional (loose)
  leptons
• Counting experiment
• lt 1 SM event expected, zero observed

CDF H Lower Mass Limit CDF H Lower Mass Limit CDF H Lower Mass Limit CDF H Lower Mass Limit
e m t
e 133 --- ---
m 115 136 ---
t 114 112 ??
stable 134 134 134
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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

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Backuppery
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Evidence/discovery
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Searches forH?ee, e?, ??

• Same-sign dilepton search in 3 sigma mass windows
• Low backgrounds (limit ee search to gt 100 GeV)

No candidates, lower limits from 89-136 GeV set
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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

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Searches for fermiophobic h0
Current results not competitive with LEP, but
will be soon!
Look for peaks in diphoton mass distribtution