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Higgs Vector Boson Fusion Production and Detection at the Tevatron
Rick St. Denis – Glasgow University
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Outline Vector Boson Fusion Production of Higgs
Production cross sections and comparisons to current Tevatron favorite channels Event characteristics at MH=130, 160, GeV/c2 Comparison to LHC
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VBF Production Features
q q' W+ W- H0 e- m+ ne nm Missing Et High Pt Leptons 2 forward jets, opposite in rapidity, high mass Spin 0 Higgs correlates spins of leptons: e,m parallel and neutrinos also Dhe-jet about 1-1.5
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Kraemer vs Pythia
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Production:Check Pythia, Kraemer, Spira
Below 1
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ZH corrections
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Interesting Diversion: pp vs ppbar
ZH WH VBF gg
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VBF 25% Better in PbarP u d W+ d ppbar: u,d u W- d u W+ pp: u d d u W-
Hence: U U D U U D Ratio is 5/4 = 1.25 5 chances 4 chances
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Check of Higgs Branching Ratios
WW ZZ
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Check of Higgs BR: Pythia/Spira
20-25% differences
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Apply NLO to Pythia WH(lnbb) Used WW correction For VBF Total ZH(nnbb)
ZH(llbb) gg-WW WH-WWW VBF
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For 8fb-1
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Study Characteristics at 130, 160, 200
^ q q' W+ W- H0 e- m+ ne nm
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Pt, Rapidity of Leptons, Jets
Tev, MH=160 Pt, Rapidity of Leptons, Jets Pt Quark can be low Reasonably Triggerable Electron In CDF Quark Forward
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Rapidity of two quarks Tev, MH=160 Max h of 2 quarks Min h of 2 quarks
Dh of 2 quarks
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Missing Energy Tev, MH=160 60 GeV Met Met vs Pte Met 180o from e
Quark can be along Met
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Lepton Correlations:e-ne
Tev, MH=160 Lepton Correlations:e-ne Df (e,ne) e,neanticorrelated in f
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Lepton Correlations: e-m
Tev, MH=160 Lepton Correlations: e-m e,m correlated in y,phi and have high pt DR
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Masses Tev, MH=160 Mt for e m n Large Invariant Mass between leptons
High Invariant Mass between quarks
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Electron-Jet Separation
Tev, MH=160 Electron-Jet Separation
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Mh=130 GeV/c2, Tevatron
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Pt, Rapidity of Leptons, Jets
Tev, MH=130 Pt Quark can be low Less Triggerable Electron In CDF Quark Forward, like 160
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Rapidity of two quarks Tev, MH=130 Max h of 2 quarks Min h of 2 quarks
Dh of 2 quarks
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Missing Energy Tev, MH=130 Less Missing Et, slightly lower pt leptons
Met , q less correlated Met , e less correlated
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Lepton Correlations:e-ne
Tev, MH=130 Lepton Correlations:e-ne Df (e,ne) e,ne less anticorrelated in f
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Tev, MH=130 Lepton Correlations e,m not as correlated DR
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Masses Tev, MH=130 Mt for e m n Slightly less Invariant Mass between
leptons Less Invariant Mass between quarks
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Electron-Jet Separation
Tev, MH=130 Electron-Jet Separation Same Separation
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Mh=200 GeV/c2, Tevatron
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Pt, Rapidity of Leptons, Jets
Tev, MH=200 Pt, Rapidity of Leptons, Jets Pt Quark can be low More Triggerable Quark still Forward, not much change Electron In CDF
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Rapidity of two quarks Tev, MH=200 Max h of 2 quarks Min h of 2 quarks
Not Much Change Dh of 2 quarks
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Missing Energy Tev, MH=200 Higher Missing Et, Higher pt leptons
Met , e stronger corr. Met , q same
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Tev, MH=200 Lepton Correlations e,m much less correlated
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Lepton Correlations:e-ne
Tev, MH=200 Lepton Correlations:e-ne Df (e,ne) e,ne more anticorrelated, in f but not at 180o
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Masses Larger Invariant Mass between leptons Tev, MH=200 Mt for e m n
quarks
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Electron-Jet Separation
Tev, MH=200 Electron-Jet Separation Same l-j separation
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Mh=160 GeV/c2, LHC
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Pt, Rapidity of Leptons, Jets
LHC, MH=160 Pt, Rapidity of Leptons, Jets Pt Quark can be low Reasonably Triggerable Electron In CDF: wider distn At LHC Quark more Forward
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Rapidity of two quarks LHC, MH=160 Max h of 2 Quarks Min h wider –
Dh of 2 Quarks wider
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LHC, MH=160 Missing Energy A bit larger at LHC
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Lepton Correlations:e-ne
LHC, MH=160 Lepton Correlations:e-ne Df (e,ne) e,ne anticorrelated less sharply in f
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LHC, MH=160 Lepton Correlations e,m better correlated
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Masses LHC, MH=160 Mt for e m n Larger Invariant Mass between leptons
Higher Invariant Mass between quarks
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Electron-Jet Separation
LHC, MH=160 Electron-Jet Separation Same l-j separation
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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 m signal correlation Large missing Energy, Lepton correlations due to spin, Invariant mass of tagging jets good handles.
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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?
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Next Steps Check Cross section for VBF properly
Check correlations in MET, e, m, 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 t
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Spare Slides
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Kinematics ^ : The local CM - pay for this with PDF s
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 ^ q q' W+ W- H0 e- m+ ne nm s ^ s ^
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Vector Boson fusion Production
q q' W+ W- H0 e- m+ ne nm
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Missing Et Correlations
Tev, MH=160 Missing Et Correlations
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Tev, MH=160 Neutrinos
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Tev, MH=160 Neutrinos
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