Higgs Vector Boson Fusion Production and Detection at the

Tevatron

Rick St. Denis – Glasgow University

Outline

● Vector Boson Fusion Production of Higgs● Production cross sections and

comparisons to current Tevatron favorite channels

● Event characteristics at MH=130, 160, 200 GeV/c2

● Comparison to LHC

VBF Production Features

● Missing Et● High Pt Leptons● 2 forward jets,

opposite in rapidity, high mass

● Spin 0 Higgs correlates spins of leptons: e,parallel and neutrinos also

● e-jet about 1-1.5

qq'

q

W+

W-

q'

H0

W+

W-

e-e-

+

e

Kraemer vs PythiaComparison of Pythia to Kraemer

0.80

0.82

0.84

0.86

0.88

0.90

0.92

0.94

0 50 100 150 200 250

Higgs Mass (GeV/c2)

Kra

em

er/

Py

thia

whlnubbbar

zhnunubbbar

zhllbbbar

Production:Check Pythia, Kraemer, Spira

Kraemer Variation in Correction to Pythia LO for WH

0.00

0.20

0.40

0.60

0.80

1.00

1.20

100 110 120 130 140 150 160 170 180 190 200

Higgs Mass (GeV/c2)

(NL

O+

EW

)/L

O

Below 1

ZH correctionsKraemer Variation in Correction to Pythia LO for ZH

0.00

0.50

1.00

1.50

2.00

2.50

100 110 120 130 140 150 160 170 180 190 200

Higgs Mass (GeV/c2)

(NL

O+

EW

)/L

O

Interesting Diversion: pp vs ppbar

Ratio of (ppbar-H->X)/(pp->H->X) at 1960 GeV

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

5.00

100 110 120 130 140 150 160 170 180 190 200

Higgs Mass (GeV/c2)

(p

pb

ar)

/ (

pp

) wh-lnubbbar

zh-nunubbbar

zh llbbbar

gg-H-ww

wh-www

vbf

W

gg

VBF

VBF 25% Better in PbarP

u d

W+

d

d u

W-

d u

W+

u

W-

pp:u

d

ppbar:u,d

u,d

Hence: U U D

U U D

U U D

U U D5 chances 4 chances

Ratio is5/4 = 1.25

Check of Higgs Branching Ratios

Higgs Branching Ratios

0.000

0.100

0.200

0.300

0.400

0.500

0.600

0.700

0.800

0.900

1.000

100 110 120 130 140 150 160 170 180 190 200

Higgs Mass (GeV/c2)

Bra

nc

hin

g R

ati

o ccbar

bbbar

tautau

gg

zz

ww

B

WW

ZZ

Check of Higgs BR: Pythia/SpiraPythia/Spira BR

0.60

0.70

0.80

0.90

1.00

1.10

1.20

1.30

100 110 120 130 140 150 160 170 180 190 200

Higgs Mass (GeV/c2)

Py

thia

/Sp

ira

BR

BB

TAU

CC

GG

WW

ZZ

20-25% differences

Apply NLO to PythiaHiggs Events (xBr) per fb (NNLO,100% Acceptance,

Perfect Detector)

0.1

1.0

10.0

100.0

100

110

120

130

140

150

160

170

180

190

200

Higgs Mass (GeV/c2)

Ev

en

ts

wh-lnubbbar

zh-nunubbbar

zh llbbbar

gg-H-ww

wh-www

vbf

Total

Total

WH(lbb)

WH-WWWVBF

gg-WW

ZH(llbb)

ZH(bb)

Used WW correctionFor VBF

For 8fb-1

Higgs Events ( x Br) 8fb-1 (NNLO, 100% Acceptance, Perfect Detector)

1

10

100

1000

100 110 120 130 140 150 160 170 180 190 200

Higgs Mass (GeV/c2)

Hig

gs

Eve

nts

wh-lnubbbar

zh-nunubbbar

zh llbbbar

gg-H-ww

wh-www

vbf

Total

Study Characteristics at 130, 160, 200

s

qq'

q

W+

W-

q'

H0

W+

W-

e-e-

+

e

Pt, Rapidity of Leptons, Jets

Quark Forward

Pt Quark canbe low

ElectronIn CDF

Reasonably Triggerable

Tev, H=160

Rapidity of two quarks

Min of 2 quarks

Max of 2 quarks

of 2 quarks

Tev, H=160

Missing EnergyTev, H=160

60 GeVMet

Met vs Pte

Quark can be alongMet

Met 180o from e

Lepton Correlations:e-e

Tev, H=160

e,eanticorrelated in

(e,e)

Lepton Correlations: e-

e,correlatedin y,phi andhave high pt

Tev, H=160

R

Masses

High Invariant Mass between quarks

Large Invariant Mass between leptons

Mt for e

Tev, H=160

Electron-Jet SeparationTev, H=160

Mh=130 GeV/c2, Tevatron

Pt, Rapidity of Leptons, Jets

Quark Forward, like 160

Pt Quark canbe low

ElectronIn CDF

Less Triggerable

Tev, H=130

Rapidity of two quarks

Min of 2 quarks

Max of 2 quarks

of 2 quarks

Tev, H=130

Missing EnergyLess Missing Et, slightly lower pt leptons

Tev, H=130

Met , e less correlatedMet , q less correlated

Lepton Correlations:e-e

Tev, H=130

e,e less anticorrelated in

(e,e)

Lepton Correlations

e,not as correlated

Tev, H=130

R

Masses

Less Invariant Mass between quarks

Slightly less Invariant Mass between leptons

Mt for e

Tev, H=130

Electron-Jet SeparationTev, H=130

Same Separation

Mh=200 GeV/c2, Tevatron

Pt, Rapidity of Leptons, Jets

Quark stillForward, not muchchange

Pt Quark canbe low

ElectronIn CDF

MoreTriggerable

Tev, H=200

Rapidity of two quarks

Min of 2 quarks

Max of 2 quarks

of 2 quarks

Tev, H=200

Not MuchChange

Missing EnergyHigher Missing Et, Higher pt leptons

Tev, H=200

Met , q same Met , e stronger corr.

Lepton Correlations

e,much less correlated

Tev, H=200

Lepton Correlations:e-e

Tev, H=200

e,e more anticorrelated, in but not at 180o

(e,e)

Masses

Larger Invariant Mass between quarks

Mt for e

Tev, H=200Larger Invariant Mass between leptons

Electron-Jet SeparationTev, H=200

Same l-j separation

Mh=160 GeV/c2, LHC

Pt, Rapidity of Leptons, Jets

Quark moreForward

Pt Quark canbe low

ElectronIn CDF: wider distnAt LHC

Reasonably Triggerable

LHC, H=160

Rapidity of two quarks

Min –wider

Max of 2 Quarkswider

of 2 Quarkswider

LHC, H=160

Missing Energy

A bit larger at LHC

LHC, H=160

Lepton Correlations:e-e

LHC, H=160

e,e anticorrelated less sharply in

(e,e)

Lepton Correlations

e,better correlated

LHC, H=160

Masses

Higher Invariant Mass between quarks

Larger Invariant Mass between leptons

Mt for e

LHC, H=160

Electron-Jet SeparationLHC, H=160

Same l-j separation

Conclusions● Cross sections and widths disagree at

20% level● NLO variation with scale can be large● Yield of VBF about 10% of gg->WW can

enhance after cuts● MET, Et and rapidity coverage for CDF

electrons fine, muons may need tricks using e signal correlation

● Large missing Energy, Lepton correlations due to spin, Invariant mass of tagging jets good handles.

Conclusions (cont)

● Best at 160, suffers some e-mu decorrelation and lower pt for lower masses, emu decorrelation but higher pt at higher mass.

● Detection in this mode relies on spin of Higgs: if you find it, how much have you also measured that it is spin 0?

Next Steps

● Check Cross section for VBF properly● Check correlations in MET, e, , jet for

help in mass reco/ efficiency● Study backgrounds for same distributions● Develop estimators: avoid hard cuts in

order to conserve events● Move on to real simluations● Study W to jet possibility, Higgs to

Spare Slides

Kinematics s● : The local CM - pay for this with PDF

● MW Can keep small with W off shell

● MH Can also reduce with H off shell

● Can emit ISR to give pt

to H, but costs PDF

s

ss

qq'

q

W+

W-

q'

H0

W+

W-

e-e-

+

e

Vector Boson fusion Production

qq'

q

W+

W-

q'

H0

W+

W-

e-e-

+

e

Missing Et CorrelationsTev, H=160

NeutrinosTev, H=160

NeutrinosTev, H=160