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Higgs branching ratios study
Oct. 13 2012Hiroaki Ono (NDU)
Oct. 13 2012 ILC Physics WG general meeting
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Current status of Higgs BR study
• Higgs branching ratios analysis publication– Ecm=250 and 350 GeV Hbb, cc, gg channel– Submitted to EPJ, now under review…
• Detailed Baseline Document (DBD) study– Detector benchmarking study for ILD• e+e-ννh @ 1 TeV branching ratio study
– Physics chapter• Update results with Higgs mass of 125 GeV
Oct. 13 2012 ILC Physics WG general meeting
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vvh detector benchmarking study
Oct. 13 2012 ILC Physics WG general meeting
e+e-vvh is one of the DBD detector benchmarking processObservable: cross section times branching ratios (σ×BRs)Decay channels: hbb, cc, gg, WW*, μμ
• Jet energy resolution (Reconstructed Higgs mass)• Jet clustering and reconstruction (with γγ BG overlay)• Flavor tagging performance (b/c tagging)• Tracking performance, momentum resolution (Hμμ)
Evaluate ILD detector performance at Ecm=1 TeV
We perform the full detector simulation with latest reconstruction packages in ILD
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Higgs physics at ILC 1 TeV
Oct. 13 2012 ILC Physics WG general meeting
Higgs mainly produced via e+e- νeνeh (WW-fusion)
Final state only comes from Higgs decay• Hbb, cc, gg (two jets)• HWW* (four jets via fully hadronic decay)• Hμμ (dilepton)γγhadron BG is also overlaid as same as CLIC study
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Simulation condition
Oct. 13 2012 ILC Physics WG general meeting
Higgs mass: Mh=125 GeVCM energy: Ecm=1 TeV Beam polarization: P(+-0.8, -+0.2)L=500 fb-1 for both pol.
Channel BRsbb 57.8%cc 2.7%gg 8.6%WW 21.6%μμ 0.02%
Detector model: ILD_o1_v05Simulation: Mokka v01-14-01-p00Reconstruction: Marlin v01-16-00• Detector mass simulation was finished• Mass reconstruction is still on-going
Higgs signal sample
Softwares
Higgs BRs @Mh=125 GeV
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Hbb, cc, gg channel
Oct. 13 2012 ILC Physics WG general meeting
Hbb, cc, gg hadronic
• Simply final state forms two jets• γγhadron background is also overlaid on signal
• Apply forced two jet clustering at firstTry different jet clustering algorithm• Durham (LOI)• kt algorithm (used in CLIC CDR for hadron collider)• R parameter(jet-radius) should be tuned
Only check signal samples at this moment…
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Invariant mass distribution
Oct. 13 2012 ILC Physics WG general meeting
Without γγhadron overlay
Invariant mass (GeV) Invariant mass (GeV)
w/o BG overlay w/ BG overlay
• Cut on the angler distribution• Different jet clustering
DurhamkT jet algorithm (as same as CLIC CDR)
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kT jet clustering
Oct. 13 2012 ILC Physics WG general meeting
Invariant mass (GeV)
Dijet reconstruction with γγhadron BGUse Durham w/o BG overlay
Optimize R parameter forkT algorithm
R=1.0~1.3 looks suitable
Check with forward particlebefore jet reconstruction
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Jet reconstruction with PFO cut
Oct. 13 2012 ILC Physics WG general meeting
Dijet reconstruction with γγhadron BG
w/o BG w/ BG kT w/ BG kT (cosθ<0.98) W/ BG inv. M (cosθ<0.98)
Check with small statisticsSlightly improve the PFO cosθ cut
Set R=1.1 for kT algorithm
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HWW* channel
Oct. 13 2012 ILC Physics WG general meeting
HWW* (one on-shell W) from Higgs decayHWW*qqqq fully hadronic decay channel is considered
h
W1
W21. Apply forced four jet clusteringEmploy kT algorithm with R=1.0
2. Jet paring for W1, W2 (W1 is on-shell with J1, J2)Select best candidate with minimizing χ2
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Reconstructed masses
Oct. 13 2012 ILC Physics WG general meeting
MH Mw1 Mw
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Conclusion
• We concentrate the studies for DBD– vvH @ 1TeV– Detector simulation has been finalized– Reconstruction is now still on-going
– Schedule is quite tight but need to finalize by LCWS12
Oct. 13 2012 ILC Physics WG general meeting