Download - 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
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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
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Bkg GMSB
Bkg GMSB
MET MET
MET MET
trkIso1 trkIso1
trkIso2 trkIso2
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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.
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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