DØ Higgs II
Gordon Watts
for the
collaboration
Outline
Channels
HWW*
H
SM, TopColor, 4th Generation
SM, TopColor, Fermiphobic Higgs
H++H--++-bbhbbbb
Triplet models; LR symmetric
SUSY High tan b
Current Status, Future Possibilities
Gordon Watts (UW Seattle) WIN’2003 10/07/2003
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*
HWW
Production & Decay
SM production primarily gluon fusion
Analysis looks for decay to lnln where l=e,
Basic Analysis Cuts
Lepton ID (High pT, medium pT)
Mass & angle cuts to eliminate Z & *
Missing Transverse Energy
Actual Cuts for Each
Channel listed on web
Cap on Jet Activity (40 GeV)
pages
Cross Section Limit
Gordon Watts (UW Seattle) WIN’2003 10/07/2003
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*
HWW
ee
e

Lumi
118 pb-1
102 pb-1
114 pb-1
Obs
0
1
1
Expected
1.1±0.8
0.9±0.5
0.95±0.12
In mass range 114-200 GeV/c2
sBR (ee+e) < 0.45–2.8 pb
sBR () < 0.2–0.7 pb
This will probably not be a
SM search in Run II
Gordon Watts (UW Seattle) WIN’2003 10/07/2003
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*
HWW
Expectations
Efficiency
Currently x2 less than Higgs/SUSY workgroup result
Mostly in Lepton ID
Internal version of analysis has much better ID
efficiency using more advanced tools
SM
Not at the Tevatron
Non-SM
Enhanced coupling for WW in top color and 4th
generation models.
Gordon Watts (UW Seattle) WIN’2003 10/07/2003
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H
SM
Rate is too low to
be observed at the
Tevatron
• Models with suppressed
fermion-Higgs coupling
• Some Universal ED
models
Gordon Watts (UW Seattle) WIN’2003 10/07/2003
Excluded
non-SM
MH[GeV/c2]
6
H
Assume SM Higgs Production Cross-Section pp  hX  X
Photon ID, Apply Sliding Mass Window Cut
Events/8 GeV
DØ RunII Preliminary
M
Limit
DØ RunII Preliminary
Data
SM BG Sum
DY
QCD
Top Color Higgs
Assume BR(H) = 1
d(M) ~ 2.5 GeV/c2
Gordon Watts (UW Seattle) WIN’2003 10/07/2003
Luminosity = 51.8 pb-1
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HExpectations
With 50 pb-1 and BR=1
we expected a larger
limit
Higgs/SUSY WGR
Working on bringing
down the jet-photon
misidentification rate
Top Color Higgs
Gordon Watts (UW Seattle) WIN’2003 10/07/2003
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±±
H
Production
qqZ /*H++H--
• Higgs Triplet Model
• LR Symmetric
versions
• Attractive as
alternative to
SUSY (CP, Mn)
• Sharply falling s at the
Tevatron
Gordon Watts (UW Seattle) WIN’2003 10/07/2003
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±±
H
Production
DØ look in the muon channel
•e, t(harder) possible
• Requires >=2 isolated 
• opening angle cuts (Z)
• 2  of like sign
(preselection)
Analysis
Cuts
e = (0.47-0.50)±0.01 for MH = 80-200 GeV/c2
Gordon Watts (UW Seattle) WIN’2003 10/07/2003
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±±
H
Results
• Luminosity = 107 pb-1
• M(H±±) > 95 GeV @ 95% c.l. (right-handed)
• M(H±±) > 116 GeV @ 95% c.l. (left-handed)
– world’s best limit
Gordon Watts (UW Seattle) WIN’2003 10/07/2003
• Efficiency will
improve with
improved lepton ID
• Under
Verification
• Cross section is
sharply falling
• 80 GeV/c2, 31
events
• 200 GeV/c2, 0.48
events
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SUSY Large tan b Search
Promising SUSY channel at the Higgs/SUSY WS
~tanb
Since then
• Great deal of theory work
• NLO cross sections almost
done
• Generation parameters
better understood
• bh channel better developed
Gordon Watts (UW Seattle) WIN’2003 10/07/2003
CP-odd Higgs
Production
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SUSY Large tan b Search
• Jet ID
• b-tagging
• b-tag e3
• dijet mass window cut
• HF Jet Corrections
CompHEP
+ Pythia
MC
mh = 120
GeV/c2
Higgs WG DØ Expectations
Coming soon to a conference near you …
Gordon Watts (UW Seattle) WIN’2003 10/07/2003
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If we didn’t show this…
Indirect Higgs Search…
LEPEWWG Sum’03
Further Constrain the SM
dMt < 2.5 GeV/c2
Currently 5.1 GeV/c2*
dMW < 40 MeV/c2
Currently 59 MeV/c2 *
We have a long way to go…
*these are combined, Run II predictions are per experiment
Gordon Watts (UW Seattle) WIN’2003 10/07/2003
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Workshop
Plots & Efficiencies
The Public Higgs pages contain most plots and many
more efficiency numbers: www-d0.fnal.gov  At Work
 Physics Groups  Higgs  Public Documents. Look
at the 2003 result links.
Details
Anyone here from DØ has access to our internal notes
and should be able to answer further questions during
this conference!
Gordon Watts (UW Seattle) WIN’2003 10/07/2003
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Conclusions
•
•
Initial results for , WW*, and H++H-- shown.
Analysis for hbb forthcoming. Other non-SM analyses being worked
on
– Charged Higgs, taus, etc.
•
All results shown based on old version of analysis software
•
Data Set Size
•
No detailed study of TeV Run II Reach
•
Stay tuned!
– Results to be released for winter conferences should have improved
understanding of detector.
– Tracking and b-tagging in particular.
– About 100 pb-1 of data shown.
– Winter conferences should have over 200 pb-1!
– Run 2b Si cancellation strongly affects any analysis dependent on
tracking (btagging, electron identification, muon identification, etc).
– DØ is still studying how best to optimize the new situation.
Gordon Watts (UW Seattle) WIN’2003 10/07/2003
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