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HWW  mnmn. R.González , J.Cuevas,J.Fernández , J.Vizán , L.Lloret , C.Jordá , R.Vilar , J.Duarte ……. Multivariate analysis : BDT. pT of the muons Missing Et Invariant Mass Dphi Transverse mass Dphi ( mu,MET ) Eta of the muons NTracks SumEt. MET. Usual variables.

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HWW  mnmn

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Hww mnmn

HWWmnmn

R.González, J.Cuevas,J.Fernández, J.Vizán, L.Lloret, C.Jordá, R.Vilar, J.Duarte…….


Multivariate analysis bdt

Multivariateanalysis: BDT

  • pT of themuons

  • Missing Et

  • InvariantMass

  • Dphi

  • Transversemass

  • Dphi(mu,MET)

  • Eta of themuons

  • NTracks

  • SumEt

MET

Usual variables

Other variables

Mtmax

Ptmin

Dphi(m,MET) min

  • Selectionstrategybasedonmultivariateanalysis: BDT

  • Variables usedfor training the BDT:

    (after Muon Selection)


Hww mnmn

-Jet veto notapplied in thisbdtanalysissome variables providing jet informationusedinstead

Sum of the energy of all jets in the event

with Et>15 GeV, eta<2.4

Number of trackswithsomequalitycuts:

-pt>3 GeV

-N hits > 5

- |zTrack-zVer|<0.4 cm

  • Mostimportant variables toreject

  • ttbarbackground

  • Variables alreadyincorporatedtothe BDT studyfor CMS Note (seeappendix)

  • Definition of Ntracks variable willbeupdated in 21X (new qualitycutsfortracksstudied Nhits> 8 , |zTrack-zVer|<0.2 cm).

  • Study in detail jets withtracks, particleflow, jet Energycorrections…

Plansfor 21x


Tmva output

BDT Ranking result

(top variable isbestranked)

---------------------------------------------------

Rank : Variable : Variable Importance

---------------------------------------------------

1 : Dphill : 2.819e-01

2 : Mtmin : 1.573e-01

3 : etalepmin : 8.728e-02

4 : MET : 7.767e-02

5 : etalepmax : 6.933e-02

6 : InvMass : 6.621e-02

7 : ptlepmin : 4.916e-02

8 : DphiLepMetmin : 4.636e-02

9 : SumEt : 4.154e-02

10 : DphiLepMetmax : 3.520e-02

11 : Mtmax : 3.438e-02

12 : Ntracks : 3.290e-02

13 : ptlepmax : 2.069e-02

TMVA output

Training againstttbar

Rank : Variable :Variable Importance

-- -------------------------------------------------------------

1 : Ntracks : 2.591e-01

2 : SumEt : 2.091e-01

3 : Mtmin : 8.163e-02

4 : ptlepmin : 8.008e-02

5 : InvMass : 7.526e-02

6 : Dphill : 6.305e-02

7 : etalepmax : 4.709e-02

8: DphiLepMetmin : 3.763e-02

9 : etalepmin : 3.607e-02

10 : Mtmax : 3.565e-02

11 : MET : 3.057e-02

12 : DphiLepMetmax : 2.759e-02

13 : ptlepmax : 1.722e-02

  • Ntracks and SumEt

  • mostuseful variables to

  • rejecttt

  • Dphimostuseful variable toreject WW

Training against WW

Overtraining checked by TMVA

Using independent samples

Distribution of the variables formainbackgrounds WW and ttbarhavediferentshape

2 independent trainings tried: against WW and ttbar

Example: training at mH=160 GeV


Hww mnmn

Signal Mh=160

WW

X axis  output from a BDT trainedagainst WW

Y axis  output from a BDT trainedagainsttbar

ttbar

DY

Firstapproach circular cutaround

theregionwithhighest s/b

  • 3 training points : 130, 160, 190

  • the resulting functions are combined into a bidimensional one

  • This method Provides also good rejection against other backgrounds like Z+jets, w+jets…

R=sqrt( (x0-bdt1)2 + (y0-bdt2)2)


Hww mnmn

ExampleformH=160

Distributions of

Some variables before and

afterapplyingthe BDT cut

(maximizingsignificance)

InvMass

MET

InvMass<50

Example of usingthe BDT toestimatecutstobeappliedon a sequentialcutanalysis.

Cutvaluesused

In thesequential

analysis

MET>45

(MET>48)

dPhi

dPhi<1.2(69º)

(dPhi<57º)

Ptmax

Ptmin

NTracks

Ptmax>30

Ptmax<50

(Ptmax>28)

(Ptmax<50)

Ptmin>25

(Ptmin>25)

Ntracks<10


Hww mnmn

mH=160 GeV

5s significance around 160 almost

achieved with mumu channel ONLY

Numbers including fake rate estimation

background vs signal events for various cuts on BDT function.


Preliminary results 21x samples 10 tev

Preliminary results 21x samples (10 TeV)

HWW 165: RelVal (CMSSW_2_1_9)

TTbar: /TauolaTTbar/Summer08_IDEAL_V9_AODSIM_v1/AODSIM

Zmumu: /Zmumu/Summer08_IDEAL_V9_AODSIM_v1/AODSIM

low statistics for tt

HWW165


Hww mnmn

HWW 165

HWW 165

TTbar

CMSSW_1_6_12

CMSSW_2_1_9

HWW 165

16X: @14 TeV

21X: @10 TeV

Zmumu:

CSA07 Vs.:

HWW 165: RelVal (CMSSW_2_1_9)

TTbar: /TauolaTTbar/Summer08_IDEAL_V9_AODSIM_v1/AODSIM

Zmumu: /Zmumu/Summer08_IDEAL_V9_AODSIM_v1/AODSIM


Hww mnmn

Analysis based in sequential cuts for 21x

→Started

Kinematic variables performingwell

Stilltoincludethe pre-selection

HWW 165

Relative efficiencies w.r.t. the previous cut at each level


Hww mnmn

BACKGROUND ESTIMATION WITH DATA

Estimation of the number of events from data in the 0 jet bin using soft muons(*), coming from B semileptonic decays in b jets produced in top decays, so basically, estimation of top-antitop fraction, from “well measured” 2 and >=2 jet bins, extrapolate to 0 jet bin.

  • Simple selection of events:

  • HWW 2 m selection/isolation

  • MET>50 GeV

  • |Mll-MZ|<20 GeV

  • presence of a soft muon (pT>5 GeV, no isolation required)

  • With this simple selection, still presence of tW, W+jets, Z+jets and WW in most relevant bins (0-4), at the level of 10-15%.

tt dimuons,

chowder 1_6

(*) see talk by Dmytro Kovalsky http://indico.cern.ch/getFile.py/access?contribId=2&resId=1&materialId=slides&confId=42770


Next steps for 21x

Next steps for 21x

Better estimation of the fake using QCD samples (large statistics)

Better estimation of the background contamination with data driven methods

Study of muon identification and isolation

Improve results in low mass region

….


Backup

BACKUP

  • Trainings y resultados 130,190


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