1

Status of WW analysis in 2011

S. Li1,2, Y. Liu1

E. Monnier2, Z. Zhao1

Center of Particle Physics and Technology, University of Science and Technology of China1

& Centre de Physique des Particules de Marseille, CNRS/IN2P32

On behalf of WW analysis team of Electroweak WG

2

Selection 2010 2011Trigger Period dependent trigger and

Lumi-weighter for MC09EF_e20_medium

EF_e18_MG(Not available until MC10a)

Electron Electron Energy Scaling applied No longer neededOTx cleaning OQ maps Use el_OQ instead

Electron smearing for MC Syst. study only Not considered for the moment

IsEM Tight Tight with Track matchMuon Combined Staco muon / mu_staco_tight = 1

ID track quality / Adding NBLHit>0If expected

Jet JES scale EM+JES OffsetEtaJES for MC10(no need for data11 or MC10a)

MET cleaning Veto evts with LooseBad Jets Veto evts with LooseBad OR Ugly Jets, OR MET_RefFinal_sumet<0.

Kinematics |η|<3.0, pT(EM+JES)>20GeV |η|<4.4, calib pT>20GeV(30GeV?)

MET( MET_project calculated and in use)

MET_LocHadTopo based with e/µ energy correction propagated

MET_RefFinal with e/µ energy correction propagated

Event Selection Generally following up the same strategy so as to quickly converge before pLHC

New WW Analysis Baseline Selection for pLHC : https://twiki.cern.ch/twiki/bin/view/AtlasProtected/BaslinecutsforWWatPLHC Dramatic changes w.r.t. 2010 Winter Conf. effort:

Highlights FOR 2011 WW ANALYSIS towards pLHC

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ee eµ µµ

All events(Dilep skimmed)

127699

GRL 114222MET cleaning 108386

MET_RefFinal_etsum>0. 108336GoodVtx>=3Trks

108065

Trigger 33578 58474 25291

==2 oppo charge leptons 2272 48 4250

Mll>15GeV 2268 - 4223

|Mll – Zmass|>10GeV 298 - 616

MET_project Cut 3 19 13

Full Jet Veto 2 4 4

Egamma and Muons stream merged with duplicated events removed data11_7TeV.00%.physics_Egamma.merge.NTUP_SMDILEP.f354_m765_p503_tid295164_00

data11_7TeV.00%.physics_Muons.merge.NTUP_SMDILEP.f354_m765_p503_tid295185_00

2011 WW cutflow challenge towards pLHC: run 178044&178109

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ch RunNumbe

r

EventNumbe

r

LB MET_project

/GeV

MET_RefFinal

/GeVpT(ll)/GeV

Inv.M(ll)

/GeVee 178044 31696531 335 46.5 46.6 18.3 255.0

ee 178109 4180116 180 42.4 49.5 16.9 64.7

eµ 178044 26558144 292 83.6 83.6 71.6 95.3

eµ 178044 7409347 143 70.9 70.9 53.5 17.6

eµ 178109 35443869 439 20.4 31.6 2.2 72.3

eµ 178109 57534414 664 20.4 20.4 29.7 94.6

µµ 178044 10796683 171 56.8 56.8 52.1 80.1

µµ 178044 46488279 477 76.5 76.5 69.8 104.1

µµ 178109 57138213 659 51.5 51.5 63.5 78.8

µµ 178109 66584945 765 63.0 63.0 72.7 44.9

New Events in 2011 period data by WW baseline selection

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Data/MC comparison between 2011 data and mc10: ee(periodB2, 178044&178109, 11.6pb-1 normalized,new jet selection: jet pt>20GeV, |η|<3.0)

6

Data/MC comparison between 2011 data and mc10: eµ(periodB2, 178044&178109, 11.6pb-1 normalized, new jet selection: jet pt>20GeV, |η|<3.0)

7

Data/MC comparison between 2011 data and mc10: µµ(periodB2, 178044&178109, 11.6pb-1 normalized, new jet selection: jet pt>20GeV, |η|<3.0)

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WW selection exercise in 2011 data:Jet Multiplicities

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ee eµ µµ All ch(stat. err)

Jet pt threshold 20GeV 30GeV 20GeV 30GeV 20GeV 30GeV 20GeV 30GeV

Data 1 1 3 5 5 6 9 12

WW→ll 0.28 0.32 1.58 1.91 0.61 0.73 2.46±0.02

2.96±0.02

DiBoson 0.01 0.02 0.16 0.21 0.04 0.05 0.21±0.02

0.28±0.02

Top 0.04 0.10 0.14 0.46 0.05 0.21 0.23±0.02

0.78±0.03

Wjets 0. 0. 0.06 0.20 0.03 0.14 0.08±0.05

0.34±0.10

Zjets 0. 0. 0.22 0.25 0.03 0.06 0.25±0.09

0.32±0.10

DrellYan 0. 0. 0. 0. 0. 0. 0. 0.

WW→l+tau 0.02 0.02 0.14 0.17 0.04 0.05 0.20±0.01

0.25±0.01

JF17 0. 0. 0. 0. 0. 0. 0. 0.

11.6pb-1 2011 data and MC10 with bunch train pile-up: 20GeV/30GeV jet pt threshold migration impact

37.1/,50.1/:30

33.1/,54.2/:20

BSSBSGeV

BSSBSGeVNo interesting benefit observed mainly due to TOP

background enriching

10

A bit PileUp effect study

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Pile-Up effects in 2011 data:Using Zmumu sample (Without JES correction)

20102011

12

Jet Multiplicities w.r.t. various NVtx bin:2010 normalized to 2011(Without JES correction)

13

A first exercise of 2011 data and MC10 have been presented

New baseline selection more or less determined. No dramatic object ID optimization expected except for isolations before pLHC. Cut flow challenge is ending up soon.

Basically following up previous Rel.15 winter conf. strategy while updating latest recommendation from CP groups

Bunch train pile-up MC10(150ns bunch-spacing) samples are considered for the moment (with no pile-up reweighting applied for current DATA/MC comparison plots, will be done soon). Will go for MC10a(75ns bunch-spacing) as soon as they are ready.

A first look indicates not too much background introduced with higher pT threshold for jets(20GeV→30GeV, due to pile-up effects). Got a worse S/B but a bit better S/√(S+B). Data-driven background estimations(Wjets, Top, DY, etc.) still need to be done as soon as possible targeting a more robust result.

Summary

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Spare

15

ee eµ µµ

All events(Dilep skimmed)

56714 56714 56714

GRL 47613 47613 47613MET cleaning 45094 45094 45094

MET_RefFinal_etsum>0. 45067 45067 45067GoodVtx>=3Trks

44955 44955 44955

Trigger 14046 24546 10656

==2 oppo charge leptons 947 16 1824

Mll>15GeV 945 - 1813

|Mll – Zmass|>10GeV 110 - 245

MET_rel Cut 1 7 6

Full Jet Veto 1 2 2

Egamma and Muons stream merged with duplicated events removed data11_7TeV.00178044.physics_Egamma.merge.NTUP_SMDILEP.f354_m765_p503_tid295164_00

data11_7TeV.00178044.physics_Muons.merge.NTUP_SMDILEP.f354_m765_p503_tid295185_00

2011 WW cutflow challenge towards pLHC: run 178044