QCD Control Sample

Shilei ZangUniversity of Colorado, Boulder

GMSB Meeting, 1 Aug 2008

QCD Control Sample

• γγ • HLT; trkIso<9; HoE<0.1; not electron; at least 2 γ;

• Pt1>90; Pt2>30; (dE>0)• eγ• HLT; trkIso<9; HoE<0.1;

• Electron: haveSeeds && # of track (Pt>1.5; ΔR<0.1)>=1

• at least 1e1γ;

• Pt1>90; Pt2>30; (dE>0)

• γγ control• HLT; trkIso<9 or trkIso>12; HoE<0.1; not electron; at least 2 γ;

• Pt1>90; Pt2>30; (dE>0); do not satisfy γγ• eγ control• HLT; trkIso<9 or trkIso>12 ; HoE<0.1; at least 1e1γ;

• Pt1>90; Pt2>30; (dE>0); do not satisfy eγ

3

Bkg GMSB

Bkg

• 1/fb

• Blue: γγ

• Red: γγ control (or eγ)

• γγ : 80 signal; 2698 bkgs

• γγ control : 55 signal; 3157 bkgs

• eγ : 61 from bkgs

γγ vs. γγ-control γγ vs. γγ-control

γγ vs. eγ

2222 )8221(0232.0)8221(03.148.1)( PtPtPtPtMET

• Jet resolution:

• MET resolution:

)(/ PtMET

2222 044.032.17.4)( PtPtPT

|)()(| 21 TT ppPt

2222 044.032.17.4)( PtPtPt

2222 )82(0232.0)82(03.148.1)( TT EEMET

Signal yield: Control sample:

MET

)(/ METMET

trkIso

PttrkIso /

1Pt

MET vs. for background (left) and for GMSB signal (right).

2222 044.032.17.4)( PtPtPt

k=5.0

k=5.0

pt1>80, pt2>20

Bkg GMSB

)( Pt )( Pt

MET MET

has powerful separation. almost no correlation with Pt1, Pt2, trkIso. (but MET has.)

|))()((|/ 21 TT ppMET

)(/ PtMET

Signal yield: Control sample:

MET

)(/ METMET

trkIso

PttrkIso /

1Pt

• HLT; HoE<0.1; not electron; at least 2 γ;

• Pt1>80; Pt2>20;

• Electron: haveSeeds && # of track (Pt>1.5; ΔR<0.1)>=1

Di-photons: Control sample:

trkIso <9 >12

trkIso/Pt <0.08 >0.1

Pt1 >120 <90

Pt2 >60 <30

Pt1& Pt2 Pt1>110&&Pt2>50 Pt1<90 or Pt2<30

Selected Sample

(gumbo & chowder)

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Bkg GMSB

Bkg GMSB

Pt1 Pt1

Pt2 Pt2

trkIso1 trkIso1

trkIso2 trkIso2

8

Bkg GMSB

Bkg GMSB

MET MET

MET MET

trkIso1 trkIso1

trkIso2 trkIso2

9

Bkg GMSB

Bkg GMSB

MET MET

MET MET

trkIso1/Pt1 trkIso1/Pt1

trkIso2/Pt2 trkIso2/Pt2

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Bkg GMSB

Bkg GMSB

MET MET

MET MET

Pt1 Pt1

Pt2 Pt2

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• HoE<0.1; track un-match

• Pt1>80; Pt2>20;

• Blue: trkIso<9 (4828 evts)

• Red: trkIso>12 (550 evts)

• HoE<0.1; track un-match

• Pt1>80; Pt2>20;

• Blue: trkIso/Pt<0.08 (3011 evts)

• Red: trkIso/Pt>0.1 (771 evts)trkIso trkIso/Pt

MET MET

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BkgGMSB

Bkg GMSB

trkIso1 trkIso1

trkIso2 trkIso2

MET/σ(γPt)

MET/σ(γPt) MET/σ(γPt)

MET/σ(γPt)

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BkgGMSB

Bkg GMSB

trkIso1/Pt1 trkIso1/Pt1

trkIso2/Pt2 trkIso2/Pt2

MET/σ(γPt)

MET/σ(γPt) MET/σ(γPt)

MET/σ(γPt)

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BkgGMSB

Bkg GMSB

Pt1 Pt1

Pt2 Pt2

MET/σ(γPt)

MET/σ(γPt) MET/σ(γPt)

MET/σ(γPt)

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BkgGMSB

Bkg GMSB

Pt1+Pt2 Pt1+Pt2

Pt2 Pt2

MET/σ(γPt) MET/σ(γPt)

Pt1 Pt1

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• Blue: trkIso<9 (4828 evts)

• Red: trkIso>12 (550 evts)• Blue: trkIso/Pt<0.08 (3011

evts)

• Red: trkIso/Pt>0.1 (771 evts)

trkIso trkIso/Pt

MET/σ(γPt) MET/σ(γPt)

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• Pt2>30; w/o trkIso

• Blue: Pt1>120 (2452 evts)

• Red: 80<Pt1<90 (2355 evts)

• Pt1>90; w/o trkIso

• Blue: Pt2>60 (3098 evts)

• Red: 20<Pt2<30 (2238 evts)

Pt1 Pt2

MET/σ(γPt) MET/σ(γPt)

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• w/o trkIso

• Blue: Pt1>110 && Pt2>50 (2249 evts)

• Red: Pt1<90 or Pt2<30 (5410 evts)

Pt1 & Pt2

MET/σ(γPt)

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Bkg GMSB

Bkg GMSB

Pt1 Pt1

Pt2 Pt2

MET/σ(MET) MET/σ(MET)

MET/σ(MET) MET/σ(MET)

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• Blue: trkIso<9 (4828 evts)

• Red: trkIso>12 (550 evts)

• Blue: trkIso/Pt<0.08 (3011 evts)

• Red: trkIso/Pt>0.1 (771 evts)

trkIso trkIso/Pt

MET/σ(MET) MET/σ(MET)

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• Pt2>30; w/o trkIso

• Blue: Pt1>120 (2452 evts)

• Red: 80<Pt1<90 (2355 evts)

• Pt1>90; w/o trkIso

• Blue: Pt2>60 (3098 evts)

• Red: 20<Pt2<30 (2238 evts)

Pt1 Pt2

MET/σ(MET) MET/σ(MET)

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Di-photons; 1/fb

MET/σ(MET)

MET/σ(γPt)MET

Separation: MET/σ(γPt) > MET > MET/σ(MET)

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MET/σ(γPt)

Pt1 & Pt2

MET/σ(γPt)

The best choice now: MET/σ(γPt);

Pt1, Pt2 together for the control sample

(we can get enough control events!)

Di-photons; 1/fb

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A new technique for mass variable (stopped for the moment)

• Momentum of two photons (known)

• Momentum of two gravitinos: P1x, P1y, P1z; P2x, P2y, P2z. (unknown)

• MET: METx, METy. (known)

1) Generate P1x, P1y, P1z; P2x, P2y, P2z distributions according to GMSB MC truth. (take all GM1b-GM1g GMSB simulated events for this.) sample A.

2) For each event i (not in sample A; already passed all cuts: iPt1>80, iPt2>20, iMET>80), use all events in sample A with |Pt1-iPt1|<ic1, |Pt2-iPt2|<ic2, |MET-iMET|<ic3 to calculate 4 neutrilino-mass variables:

)1,1,1(1 zPyPxPmassmass

)2,,,1,1(2 zPMETyMETxyPxPmassmass

)1,,,2,2(3 zPMETyMETxyPxPmassmass

)2,2,2(4 zPyPxPmassmass

Photon1

Photon2

Photon1

Photon2

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3) Require |mass(j)-mass(k)|<mass-cut (j, k=1, 2, 3, 4)

4) For each event i, calculate the mass likelihood:

5) Take the maximal point (maximal likelihood) as the mass of event i.

6) For all events, we get the mass distribution.

7) Between step 3) and step 4), we can also de-convolute the mass(j) distribution to get a narrower mass distribution, this may recover some information and improve the analysis.

4

1

)(j

ondistributijmasslikelihoodmass

• Narrow distribution for GMSB signal

• Wide distribution for Background

• Treat GM1b-GM1g at the same time (parameter independent)

• Can maximize the final significance.

Good

properties:

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MET formula mass

Pt1>90; Pt2>30Pt1>90; Pt2>30

Bkg GMSB (GM1e)New Mass

(preliminary)

GMSB GMSB