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