ReportJet-veto SF and Uncertainties

Jet smearing

Lailin Xu, Haijun Yang, Bing ZhouThe University of Michigan

Outline

• Jet-veto SF and uncertainties

• Effects of Jet smearing on MET• MET with/without METUtility

• WW/top/tautau background uncertainties

Jet Veto SF and Uncertainties• SF =ZZ(data)/ ZZ(MC) = Z(data)/Z(MC)• Control samples: Data (p833, 4.7 fb-1) Z ee and Z mm MC (MC11C): Z ll MC@NLO/Herwig, ALPGEN, PYTHIA• Systematic uncertainties

–Parton showing modeling (with diff. MC generator)–JES/JER (using ATLAS package to smear jet ET)

Jet-veto SF Results

• SF = 0.96 (both for ee and for mm) from MC@LNO Z MC

compared to WW analysis: SF = 0.963• Systematic uncertainty

–< 0.3% due to JES/JER–~ 5% due to different MC generator (Alpgen

gives SF = 1.00; Pythia gives SF = 1.02)

Jet smearing effects on MET:ee

With jet smearing (for all the EM-jets by hand) Compared to no jet smearing

Jet smearing effects on MET:mm

With jet smearing (for all the EM-jets by hand) Compared to no jet smearing

MET with METUtility:ee

MET with the ToolCompared to without tool

MET with METUtility:mm

MET with the ToolMET without the Tool

WW/top/tautau background estimation method

dataee

dataDYnondatae

DYnondata

datadataeeeeee

DYnondatae

DYnondataee

NNkkNN

NNkkNN

/*5.0,

/*5.0,

,,

,,

kkee ,

mce

datae

DYnondatae NNN ,

formular:

are efficiency factor for ee and mm events

gammaWmce

jetsZmce

jetsWmce

WZmce

ZZmce

mce NNNNNN ,,,,,

Here Z+jets is the DY contribution without Ztautau

10

Cut flow for ee (final 34 events)

11

Cutflow:mm (final 45 events)

Cut flow em (final numner 15)

13

estimated background after all cuts

data estimated background

mc background(WW/ttbar/tW/tautau)

ee 6.4+/-1.8+/-0.020 4.7+/-0.4+/-0.69

mm 8.4+/-2.4+/-0.027 10.8+/-1.2+/-1.66

Error propagation in data driven method

,

,

,

,

2

2 2 , 2 2

2

, 2 2

2 2

( .)

( ( .)) ( / ) / 4

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( .)

data non DYee

data non DYeee

mc non DYe

data non DYee

N

data non DYee e kN

data data datae eeN

data mc non DY data data datae e ee

N N

stat

k N

N stat N N

N N N N N

syst

,

2( .)mc non DYe

eesyst k

back up

Compared to no jet smearing

With jet smearing for all EM jets (by hand)

Compared to no jet energy smearing