clic higgs talks at ecfa lc 2013
DESCRIPTION
CLIC Higgs talks at ECFA LC 2013. Booked:. Higgs decay to b, c, and gluons @ 1.4 TeV (update). Tomáš Laštovička IoP Prague LCD-WG Analysis Meeting, April 9 th , 2013. Summary of changes. - PowerPoint PPT PresentationTRANSCRIPT
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CLIC Higgs talks at ECFA LC 2013
Booked:
Astrid Muennich Measurement of H -> tautau at 350 GeV and 1.4 TeV CLICTBN Measurement of the Higgs self-coupling at 1.4 TeV and 3 TeV CLICSophie Redford Measurement of the top Yukawa coupling at 1.4 TeV CLICTBN Extraction of H -> bb, H -> cc and H -> gg at 350 GeV and 1.4 TeV CLICTBN Higgs to gamma+gamma and Z+gamma at 1.4 TeV CLICTBN Measurement of H -> mumu at 1.4 TeV CLIC
Philipp Roloff Measurement of the top Yukawa coupling at sqrt(s) = 1 TeV using the SiD detector
(20+5 min, eventually 15+5 min)These are placeholders: titles may be changed; abstracts to be submitted
Higgs decay to b, c, and gluons @ 1.4 TeV (update)
Tomáš Laštovička
IoP Prague
LCD-WG Analysis Meeting, April 9th, 2013
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Summary of changes
1) Dominant background sample ee → qqvv (2096) with 126 GeV Higgs was replaced by 2201 sample with mH = 12 TeV.
2) ee → qqlv (2159) sample added.
3) 4Q background samples (qqqqνν, qqqq, qqqqll) from HHνν analysis added.
4) Neural net input variables added: ymin, ymax , pT of jets
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Data samples
126 GeV Higgs, 1.4 TeV, full sim/rec CLIC_SiD, γγ overlay, 1500 fb–1
Sample prodID σ [fb] # Requested # Prod/Twiki # Analyzed
ee → hvv inclusive 2019 244.1 1M 1M 980k
ee → qqvv 2201 (2096) 788 (933.8) 500k 445k (482k) 163k (458k)
ee → qq 2098 4008.8 500k 175k 166k
ee → qqlv 2159 4312.9 200k 500 66k
ee → qqll 2144 n/a 200k - -
ee → qqqqvv 1081 24.72 - - 221k
ee → qqqq 1097 1325 - - 249k
ee → qqqqll 1089 71.68 - - 164k
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Results Update
h → bb h → cc h → gg
σhνν uncertainty 0.32 % 2.9 % 1.7 %
Signal efficiency 67% (137k) 31% (3k) 22% (5.4k)
Signal purity 73% 39% 65%
h → bb h → cc h → gg
σhνν uncertainty 0.315 % 3.7 % 2.27 %
Signal efficiency 63% (127k) 26% (2.6k) 26.3% (6.4k)
Signal purity 79.5% 29% 30.2%
UP
DA
TE
D
(BR: 56.1 %) (BR: 2.83 %) (BR: 8.38 %)
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Results UpdateU
PD
AT
ED
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Next steps
Isolated lepton finder, requires to re-LCFI all samples. Data samples
– Increase statistics of • ee → qqvv, ee → qq, ee → qqlv
– No events available for• ee → qqll
– Address e-γ and γ-γ backgrounds.
Simultaneous determination of cc and gg. Whole NN classifier rather than cut and count.
– Investigate limits of the classification.
Repeat the 3 TeV Higgs decay analysis with the 126 GeV Higgs?• Re-simulate 2025 in the SiD framework
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BACKUPS slides from the last presentation
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Analysis Chain
Adapted from 3 TeV Higgs branching ratio analysis+ experience from hhνν and some minor improvements
SelectedPandoraPFOCollection with FastJet kT, R = 1.0 and exclusive 2 jets
Channel separation and jet true flavour tag– From quarks originating from initial Higgs
LCFI Flavour Tagging– Neural nets retrained on a fraction of qqνν sample– No significant improvement in analysis results (b-tag) when compared to 3 TeV
flavour tag nets.
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Neural Net Inputs
Current inputsInvariant mass and total energy of jets
Distance of jets in η – ϕ plane
Number of leptons and number of photons
Acoplanarity
Sums of jet flavour tags (b-, c-, c(b)- and b(l))
max(|ηi|)
Additional (implemented but not used at the moment)
– Event invariant mass, ymin, ymax, pTmax, pT
min, ETmiss, Σ|ηi|, isolated leptons, etc…
Highest NN input significance
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Control Plots (for the b-channel signal)
Disclaimer: does not include full set of SM backgrounds.
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Control Plots II (linear scale, normalized to 1)
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Neural Net Classification
b-channel (BR: 56.1 %) : is nice and easy– Note the linear histogram scale and good hνν inter-channel separation due to flavour tag.
c-channel (BR: 2.83 %) : is the most difficult one gluons (BR: 8.38 %) : has sizeable background from hνν
Disclaimer: does not include full set of SM backgrounds.
h → bb h → cc h → gg