hggs-d meeting mpi 11/20061 higgs physics activities in bonn/siegen jrn groe-knetter atlas-higgs-d...
DESCRIPTION
Hggs-D meeting MPI 11/20063 comparison of different jet algorithms (cone, KT with diff. par‘s), different generators (PYTHIA/HERWIG) and processes (dijet/VBF) efficiencies, fake rates, out of jet corrections different jet algos – eff. vs. eta and Pt matching between truth jets (hadron level) and reco jets within a ΔR Forward Jet Studies (Iris Rottländer) Cone 07 Cone 04 ● : Tower o : TopoTRANSCRIPT
Hggs-D meeting MPI 11/2006 1
Higgs Physics – Activities in Bonn/Siegen
Jörn Große-Knetter
ATLAS-Higgs-D TreffenMünchen, 28.11.2006
Hggs-D meeting MPI 11/2006 2
Outline• VBF Fusion:
• forward jet tagging• central jet veto: NLO with SHERPA, different
underlying event / PS models• tau tagging• Zjj background estimate for H from data• W+jets background studies (M. Rast, not shown
here)• LVL1 trigger studies for Hinvisible
• Other non-VBF studies not shown here
• Plans/potential for collaboration
Hggs-D meeting MPI 11/2006 3
comparison of different jet algorithms (cone, KT with diff. par‘s), different generators (PYTHIA/HERWIG) and processes (dijet/VBF)
efficiencies, fake rates, out of jet corrections
different jet algos – eff. vs. eta and Pt matching between truth jets (hadron level) and reco jets within a ΔR
Forward Jet Studies (Iris Rottländer)
Cone 07 Cone 04 ● : Tower o: Topo
Hggs-D meeting MPI 11/2006 4
• Jets from hard process found easier than jets from shower• Forward region: jets from VBF found easier than jets from QCD• Maybe slight dependence on generator (shower & fragmentation model)
Pythia QCD ForwardjetsHerwig QCD DijetsPythia 6.3 VBF H->tautau->llHerwig VBF H->tautau->ll
Different MC Generators and Topologies
Hggs-D meeting MPI 11/2006 5
Central Jet Veto, NLO (Talea Köchling)• Goal: study effects of NLO on sensitivity esp. jet veto with SHERPA
• Def.: 1st and 2nd jet tagging jets, 3rd jet apply veto Signal: 3rd jet properties (including underlying event)
momentum: SHERPA3j>PYTHIA>SHERPA2JEt>HERWIG
rapidity: SHERPA agree well, HERWIG slightly wider, PYTHIA??
Hggs-D meeting MPI 11/2006 6
Survial Probability w.r.t central jet vetoSignal w/o underlying event Signal with underlying event
Veto jets with Pt > x GeV)Veto jets with Pt > x GeV)• SHERPA H+2j and H+3j agree well „NLO“ effect seems small?
• signficant difference among different MC generators
• reason not yet understood
Hggs-D meeting MPI 11/2006 7
Survial Probability w.r.t central jet vetoZjj(EW) w/o underlying event Zjj(QCD) with underlying event
Veto jets with Pt > x GeV)Veto jets with Pt > x GeV)• SHERPA H+2j and H+3j agree well only for EW process
• signficant difference in QCD process
• reason not yet understood
Hggs-D meeting MPI 11/2006 8
-ID for VBF Hlh (A. Veenendaal) from VBF Higgs decay have relatively low pT
• Check performance of ID of hadronic decays for this channel – tauRec and 1P3P
• Look for best discrimination method against Wlepton + jets background
• Own production (CSC not ready) low MC statistics
Hggs-D meeting MPI 11/2006 9
Comparison tauRec/tau1P3P
• Find best working point: tauRec better for pT>20GeV, 1P3P for pT<20GeV
• Combine both algorithms?
10 GeV < pT < 20 GeVavg. over all pT
Hggs-D meeting MPI 11/2006 11
• Idea: jjZμμ and jjZμμ with identical topology
muons are MIPS same energy deposition in calorimeters (checked!)
only difference: momentum spectra of muons
• Method: select Z μμ events
„randomise“ μ-momenta according to Z μμ4ν MC (works!)
apply „usual“ selection and mass reconstruction
shape of backgroundcan be extracted precisely from data itself
towards mass determination:
- subtract BG prediction
- Gaussian fit mass
VBF, H: determination of bkgr. from data (M. Schmitz)
Hggs-D meeting MPI 11/2006 12
Prospects for mass determination with limited luminosity 30fb-1, only decay
6 out of 8 fits fine
120fb-1, decay=30fb-1, ll decays?
all fits fine
Hggs-D meeting MPI 11/2006 13
Invisible Higgs boson decaysinvisble Higgs decays: SUSY HLSP LSP, ADD, Majoron,…
VBF most sensitive, but how to trigger on 2 jets + missing energy? LVL1 trigger study for jets including FCAL
95% CL exclusion with 30 fb-1VBF result assumes trigger on jets up to = 4.9
Hggs-D meeting MPI 11/2006 14
Ongoing LVL1 Trigger Study (Guilherme Hanninger)
Goal: determine efficiencies and rates for various options of trigger menues for combinations of ET miss + central jet + forward jet
“plain cuts”:
Hggs-D meeting MPI 11/2006 15
Estimation of LVL1 trigger efficiencies, rates
• Maybe forward + central good for background rejection? • Gain from using topological cuts: re-define boundaries?• QCD: LVL1 output rates extremely sensitive to ETmiss
topological cuts:
Hggs-D meeting MPI 11/2006 16
Plans, collaboration options• Tools:
– Forward jet tagging:• Continue jet efficiency, jet energy scale studies• Effects of pile-up, underlying event
– Tau ID:• Check other background to VBF Higgs sample• Look for improvement in the few-10GeV pT region, revise LLH/NN
with Higgs and its backgrd. samples• Analysis:
– Study central jet veto• tune cuts to be less sensitive to MC models• Continue SHERPA studies
– Continue invisible Higgs trigger studies: LV2, EF ?– Continue Zjj background studies: e-channel– Background studies (e.g. W+jets bg.)– Start HWW analysis?