I.Tsukerman ( ITEP, Moscow) Jet/MET WG meeting , clustered week, CERN, September 29,2009

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I.Tsukerman ( ITEP, Moscow) Jet/MET WG meeting, clustered week, CERN, September 29,2009

Performances of SISCone, kt and antikt H1 C4Topo jets in VBF H production

Thanks to: P.-A. Delsart, D. Rousseau, R. Seuster

• Event samples and reconstruction algorithms

• Multiplicities and jet kinematics

• Et–bias, resolution; efficiencies and impurities

• Conclusion and provisional plans

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Motivation

Jet/MET WG suggested to HWG to look at jets from SISCone and antikt algorithms long time ago

Tools exist both at ESD and AOD/AANT level, thanks to P.-A. MC08: only 10% ESD produced mostly AOD

analysisResults for local hadronic calibration were presented this

January: http://indico.cern.ch/getFile.py/access?contribId=1&resId=1&materialId=slides&confId=48206

However “H1-based” Topo jets cannot be obtained from AOD

So ESD’s for VBF Higgs production were used

Sorry for some delay with this study!

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Samples and reconstructed algorithms

Dataset 105335, 3K VBF Herwig VBF Hinvisible (m(H)=130GeV) events at

10TeV Dataset 109011, 5K VBF Sherpa VBF Hinvisible (m(H)=130GeV) events at

10TeV mc08.109011.SherpaHtoinvisibleMH130.recon.e361_s462_r635 mc08.105335.HerwigVBFH130invisible.recon.e361_s462_r635

ATLAS-GEO-02-01-00, QGSP_BERT physics list, G4.9

Initially 4 jet “collections” only (H1

C4Tower,C4Topo,C4Truth,C7Tower) Run on projective towers (or Topoclusters); limitations: Et>7GeV, ||

<5; Here also: H1 SISC4Topo, Kt4Topo, AntiKt4Topo jet collections After modified esdtocbnt.py: NTuples at /castor/cern.ch/user/z/zuckerma/mc08/Thanks to David, Pierre-Antoine and Rolf for help to prepare joboptions Private algorithm: matching true-reconstructed jets, ROOT,

R0=0.15 updated for 14.5.0 AANT with new jet collections

1. Jet properties: Jet/EtMiss WG 2. Jet tagging, veto and VBF Higgs: Higgs WG

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Jet multiplicities in VBF H events (m(H)=130

GeV) at Et>20 GeV for different collections

Multiplicities are very similar for different algorithms

||<52.7<||<5forward

2.7<||<5forward||<5

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Some definitions: reminder

Reconstruction efficiency: for TRUE jets

t, R0= N(matched) / N(all)

Impurity: for RECONSTRUCTED jets

impt, R0= M(unmatched) / M(all)

Definitions correspond to Atlas Technical Paper

Biast= <(Et(reco)-Et(true))/Et(true)> (gaussian) Resolutiont= (Et(reco)- Et(true)) / Et(true))

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Correspondence true-reco jets for cone 0.4 collections at Et>20 GeV, here R<0.5

Performances are comparable, a bit worse for Kt4

R R

central

central

forward

forward

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Et-bias and resolution for VBF Higgs events

for central jets with Et>20 GeV

-2% bias and larger left tail for Kt4; other things similar and ok

C4Topo

Kt4Topo

AntiKt4Topo

SISCone4Topo

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Et-bias and resolution for VBF Higgs events

for forward jets with Et>20 GeV

-9% bias for Kt4; other things similar and ok

C4Topo

Kt4Topo

AntiKt4Topo

SISCone4Topo

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Et-bias vs Et and for VBF Higgs events

Problems with calibration for Kt4, other things similar and ok

Et>10GeV Et>20GeV

LC: ~ok in central region, problems in EC and FCal

central

forward

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Jet reco vs Et and for VBF Higgs events

A bit worse efficiency for kt4 jets, other cases similar

Et>10GeV Et>20GeV

central forward

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Jet reco impurity vs Et / for VBF Higgs events

Impurities are a bit worse for Kt4

Et>10GeVEt>20GeV

central forward

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Conclusion and short-term plans

• H1 SISCone4Topo, Kt4Topo, antikt4Topo considered

Kt4 has problems with calibration and worse performance • New algs have comparable performance with H1

C4Topo Biases, resolutions, efficiencies, impurities, matching are

reasonable • To be done: - study of similar issues with pile-up (problem: limited

statistics) - relook at H1 and LC-based jets in release 15

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Jet multiplicities in VBF H events (m(H)=130

GeV) at Et>10 GeV for different collections

Multiplicities are slightly different

||<52.7<||<5forward

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Correspondence between true and reco jets

for cone 0.4 collections at Et>10 GeV

Performances of algorithms are comparable

R R

central

central

forward

forward

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Et-bias and resolution for VBF Higgs events

for central jet Et>10 GeV

-3% bias for Kt4 ; resolutions similar

C4Topo Kt4Topo

AntiKt4Topo

SISC4Topo

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Et-bias and resolution for VBF Higgs events

for forward jet Et>10 GeV

-10% bias for Kt4; resolutions similar

C4Topo Kt4Topo

AntiKt4Topo

SISC4Topo