Post on 27-Jan-2016
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John Marshall HZ Analyses 1
Status of the HZ Analyses
LCD WG Meeting, 03/07/2012
J.S. Marshall, University of Cambridge
John Marshall HZ Analyses 2
350GeV HZ Recoil, L=500fb-1
• Model independent recoil analysis:Z decays to charged leptons.
• Identify leptons and compute recoil mass, using knowledge of initial state.
Mean RMS
mH 119,950.4 MeV
130.4 MeV
mH 133.3 MeV
6.5 MeV
nsig 4.91 % 0.19 %
mH 119,915.4 MeV
302.5 MeV
mH 299.8 MeV
30.4 MeV
nsig 8.08 % 0.64 %
mH 120,012.0 MeV
397.2 MeV
mH 394.3 MeV
36.1 MeV
nsig 7.93 % 0.59 %
X
eeX
eeX
Brem
.
X
John Marshall HZ Analyses 3
Comparison with ILC ResultsStarting point:No selection cuts
Selection must work harder than at ILC, but achieves similar S/B
Reco quantities,full selection
mH nsig
ILC 110 MeV 5.2 %
CLIC 226 MeV 8.3 %
• Integrated luminosity: 175 fb-1
• Comparison of results for X channel:
John Marshall HZ Analyses 4
E’ Correction Weights• Try to understand shape differences using ILC/CLIC
E’ distributions from Frank.
• Use distributions to obtain E’ weight: CLICILC.
L = 175 fb-1 mH nsig
ILC 110 MeV 5.2 %
CLIC, Reco 226 MeV 8.3 %
CLIC, Reco , E’ weight 151 MeV 7.3 %
CLIC, True 174 MeV 7.0 %
CLIC, True , E’ weight 90 MeV 6.3 %
Starting point:No selection cuts
John Marshall HZ Analyses 5
Final State Radiation
L = 175 fb-1 mH nsigTrue 174 MeV 7.0 %
True post FSR 210 MeV 8.1 %
Reco 226 MeV 8.3 %
True , E’ weight 90 MeV 6.3 %
True post FSR, E’ weight 112 MeV 7.0 %
Reco , E’ weight 151 MeV 7.3 %
Starting point:No selection cuts
John Marshall HZ Analyses 6
Momentum Resolution• Attribute difference between use of
true muons, post FSR, and use of reconstructed muons to:
• Muon identification efficiency
• Momentum resolution...
Know this is high: 98%+
John Marshall HZ Analyses 7
500GeV HZ Recoil, L=500fb-1
Mean RMS
mH 119,866.8 MeV
689.2 MeV
mH 645.6 MeV
87.3 MeV
nsig 11.03 % 1.08 %mH 119,793.7
MeV1,384.1
MeV
mH 1,322.9 MeV
339.1 MeV
nsig 16.68 % 2.75 %mH 120,041.0 MeV
2,528.7 MeV
mH 2,057.1 MeV
523.3 MeV
nsig 15.85 % 2.65 %
X
eeX
eeX
Brem
.
X
• Repeat recoil analysis at 500GeV with same code and procedures.
• Corrected initial state 4-vector since last time presented 500GeV analysis.
John Marshall HZ Analyses 8
500GeV HZqq, L=500fb-1
• Model dependent analysis, with direct Higgs mass reconstruction: look for hadronic decay of H and Z.
• Force event into four jets (investigate different R values), perform kinematic fit and use B-tagging info in BDT selection.
R = 1.0
John Marshall HZ Analyses 9
500GeV HZqq, L=500fb-1
Mean RMS
mH 119,993.7 MeV
100.7 MeV
mH 103.7 MeV
3.4 MeV
nsig 1.66 % 0.02 %mH 119,995.0
MeV99.5 MeV
mH 103.8 MeV
3.9 MeV
nsig 1.60 % 0.02 %mH 119,999.0
MeV117.4 MeV
mH 123.0 MeV
5.2 MeV
nsig 1.67 % 0.02 %
R =
0.7
R =
1.0
R =
1.3
R = 1.0
• Fluctuate high statistics signal sample, and smooth background fit, to produce 1000 test samples.
John Marshall HZ Analyses 10
500GeV H, L=500fb-1
• Model dependent analysis, with hadronic decay of H and Z decaying to neutrinos.
• Previously, considered signal sample to be pure Higgsstrahlung, but cannot easily distinguish from WW-fusion process.
• Must consider new inclusive sample: hnunu
Implications for selection...
R = 1.3
John Marshall HZ Analyses 11
500GeV H, L=500fb-1
Mean RMS
mH 120,034.7 MeV
95.3 MeV
mH 94.7 MeV
1.9 MeV
nsig 1.06 % 0.01 %mH 120,015.0
MeV98.3 MeV
mH 97.8 MeV
1.6 MeV
nsig 1.01 % 0.01 %mH 120,003.6 MeV
111.0 MeV
mH 111.2 MeV
2.3 MeV
nsig 1.05 % 0.01 %
R =
0.7
R =
1.0
R =
1.3
• Fluctuate high statistics signal sample, and smooth background fit, to produce 1000 test samples.
• Switch to inclusive hnunu sample introduces several awkward features. R = 1.0
John Marshall HZ Analyses 12
500GeV H, L=500fb-1
R = 1.0
Full treatment of inclusive sample throughout analysis:
Consider only exclusive sample throughout analysis:
Train using exclusive sample, input “data” from inclusive sample:
R = 1.0R = 1.0
mH nsig
206.2 MeV 2.38 %
mH nsig
124.7 MeV 1.42 %
mH nsig
97.8 MeV 1.01 %