DØ Higgs II Gordon Watts for the collaboration. 2 Gordon Watts (UW Seattle) WIN’2003 10/07/2003 Outline Channels H WW * H H ++ H -- + + -

DØ Higgs IIGordon Watts

for the

collaboration

2Gordon Watts (UW Seattle) WIN’2003 10/07/2003

Outline

Channels

HWW*

H

H++H--++--

bbhbbbb

SM, TopColor, 4th Generation SM, TopColor, Fermiphobic Higgs

Triplet models; LR symmetricSUSY High tan

Current Status, Future PossibilitiesCurrent Status, Future Possibilities


HWW*

Production & Decay

SM production primarily gluon fusionAnalysis looks for decay to ll where l=e,

Lepton ID (High pT, medium pT)Mass & angle cuts to eliminate Z &

Missing Transverse EnergyCap on Jet Activity (40 GeV)

Cross Section Limit

Actual Cuts for Each Channel listed on web pages

Actual Cuts for Each Channel listed on web pages

Basic Analysis Cuts


HWW*

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

BR (ee+e) < 0.45–2.8 pbBR () < 0.2–0.7 pb

This will probably not be a SM search in Run II

This will probably not be a SM search in Run II

In mass range 114-200 GeV/c2


HWW* Expectations

Enhanced coupling for WW in top color and 4th generation models.

EfficiencyCurrently x2 less than Higgs/SUSY workgroup resultMostly in Lepton ID

Internal version of analysis has much better ID efficiency using more advanced toolsSM Not at the Tevatron

Non-SM


H

MH[GeV/c2]

Exclu

ded

SM

Rate is too low to be observed at the Tevatron

Rate is too low to be observed at the Tevatron

non-SM

• Models with suppressed fermion-Higgs coupling

• Some Universal ED models


H

Assume BR(H) = 1

Assume SM Higgs Production Cross-Section XhXpp

Photon ID, Apply Sliding Mass Window Cut

LimitLimitM

DataSM BG SumDYQCD

Luminosity = 51.8 pb-1(M) ~ 2.5 GeV/c2

Top Color HiggsEven

ts/8

GeV

DØ RunII Preliminary DØ RunII Preliminary


HExpectations

Higgs/SUSY WGRWith 50 pb-1 and BR=1 we expected a larger limit

Top Color Higgs

Working on bringing down the jet-photon misidentification rate

Working on bringing down the jet-photon misidentification rate


qqqqZ /Z /**HH++++HH----qqqqZ /Z /**HH++++HH----

H±± Production

• Higgs Triplet Model• LR Symmetric

versions• Attractive as

alternative to SUSY (CP, M)

• Sharply falling at the Tevatron


H±± Production

DØ look in the muon channel•e, (harder) possible

• Requires >=2 isolated • opening angle cuts (Z)• 2 of like sign

• Requires >=2 isolated • opening angle cuts (Z)• 2 of like sign

AnalysisCuts

(preselection)

= (0.47-0.50)±0.01 for MH = 80-200 GeV/c2 = (0.47-0.50)±0.01 for MH = 80-200 GeV/c2


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

• 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


SUSY Large tan Search

Promising SUSY channel at the Higgs/SUSY WSPromising SUSY channel at the Higgs/SUSY WS

Since then

• Great deal of theory work• NLO cross sections almost

done• Generation parameters

better understood• bh channel better developed

~tan

CP-odd HiggsProduction


SUSY Large tan Search

Higgs WG DØ Expectations

• Jet ID• b-tagging

• b-tag 3

• dijet mass window cut• HF Jet Corrections

Coming soon to a conference near you …

Coming soon to a conference near you …

CompHEP + Pythia MCmh = 120 GeV/c2


If we didn’t show this…

Indirect Higgs Search…Indirect Higgs Search… LEPEWWG Sum’03

Mt < 2.5 GeV/c2

MW < 40 MeV/c2

Further Constrain the SM

Currently 59 MeV/c2 *

Currently 5.1 GeV/c2*

*these are combined, Run II predictions are per experiment

We have a long way to go…


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!


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– Results to be released for winter conferences should have

improved understanding of detector.– Tracking and b-tagging in particular.

• Data Set Size– About 100 pb-1 of data shown.– Winter conferences should have over 200 pb-1!

• No detailed study of TeV Run II Reach– 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.• Stay tuned!