Zhijun Liang University of Oxford

Photon isolation efficiency study

Introduction

Motivation : Estimate photon isolation efficiency from electron sample from

Z->ee Isolation defintion:

Leakage correction Ambiant energy correction

Selection cut : Period D~H, EF_e20_medium, Egamma stream Two opp charge , tight electron , pT>25GeV , eta cut 85Gev<M(ee)<95Gev

Systematic : In-time pileup uncertainty Out-of-time pileup uncertainty pT dependence Discrepancy between electron isolation shape and photon isolation

shape

In-time pileup uncertainty(1fb-1 data)

Etcone40_corr[GeV] Etcone30_corr[GeV]

Etcone20_corr[GeV]

npV<33<=npV<=45<=npV<=6Npv>=7

Photon isolation efficiency in different NPV bins(1fb-1 data)

Etcone40_corr[GeV] Etcone30_corr[GeV]

Etcone20_corr[GeV]

npV<33<=npV<=45<=npV<=6Npv>=7

Out of time pileup effect(1fb-1 data) (bunch position dependence)

Bunch position <=34<=Bunch position <=67<=Bunch position <=9Bunch position >9

Etcone40_corr[GeV] Etcone30_corr[GeV]

Etcone20_corr[GeV]

Out of time pileup effect(1fb-1 data) (bunch position dependence)

Bunch position <=34<=Bunch position <=67<=Bunch position <=9Bunch position >9

Etcone40_corr[GeV] Etcone30_corr[GeV]

Etcone20_corr[GeV]

pT dependence effect(1fb-1 data)

Etcone40_corr[GeV] Etcone30_corr[GeV]

Etcone20_corr[GeV]

Pt<35GeV35GeV<=pT<=40GeV40GeV<=pT <=45GeVpT>45GeV

pT dependence effect(1fb-1 data)

Etcone40_corr[GeV] Etcone30_corr[GeV]

Etcone20_corr[GeV]

Pt<35GeV35GeV<=pT<=40GeV40GeV<=pT <=45GeVpT>45GeV

Discrepancy between electron and photon

Unconverted photon from Z->ee+gammaConverted photon from Z->ee+gammaElectron isolation from Z->ee

Etcone40_corr[GeV] Etcone30_corr[GeV]

Etcone20_corr[GeV]

Summary

Working progress report . Plan for Final result and systematic:

In-time pileup uncertainty Out-of-time pileup uncertainty pT dependence Discrepancy between electron isolation shape and

photon isolation shape