1
Update on Top Mass using Soft Muon Tagged Events and Atlfast II.
James Poll, QMULDr. Lucio Cerrito, QMUL
1Outline
• Brief analysis overview.
• Comparison of v13 to v14 Atlfast II.
2
1Event Selection
3
Commissioning analysisJet multiplicity
Conclusions
Commissioning analysis
Event selection
1 isolated lepton: e / µ
!ET > 20 GeV
3x jet pT > 40 GeV/c1x jet pT > 20 GeV/c
pass trigger: e / µ
Stan Bentvelsen, Alexander Doxiadis, Martijn Gosselink, Manuel Kayl, Wouter Verkerke, Ivo van Vulpentt̄ commissioning analysis 2/21
• 1 isolated lepton e > 25 GeV, μ > 20 GeV
• Veto on events with 2 high pT leptons
• 3 or more jets with pT > 40 GeV
• MET > 20 GeV
• Scalar HT > 200 GeV
• One or more b-jet with a Soft Lepton Tag (SLT)
• Pass EF e25i and mu20i triggers
1Event Selection Definitions
good electron
• e-gamma (author !=2)
• ‘medium’ (0x3FF)
• pT > 25 GeV
• |eta| < 2.5
• exclude 1.37 < |eta| < 1.52
4
good muon
• STACO muid
• algo == 1
• pT > 20 GeV
• |eta| < 2.5
• eT cone20 < 6 GeV
good jet
• cone 0.4 (tower)
• pT > 25 GeV
• |eta| < 2.5
• no e in delta R < 0.4
triggers
• e25i (EM25i)
• mu20i (MU20 || MU40)
https://twiki.cern.ch/twiki/bin/view/Atlas/TopGroupCSCObjectSelection
1MC Samples
Fullsim
ttbar:
5200: semi-leptonic, dileptonic, Mtop = 175 GeV/c2 v13.0.40
5
AtlfastII
ttbar:
5200: semi-leptonic, dileptonic, Mtop = 175 GeV/c2 v14.1.0
1Measuring the Top Mass
6
GeV
0 50 100 150 200 250
Entries
0
50
100
150
200
250
300
350
Invariant Mass
Invariant Mass of the lepton from W decay and the soft muon within the b-jet.
Invariant Mass [GeV/c2]
1Invariant Mass
10
GeV
0 50 100 150 200 250
Entries
0
50
100
150
200
250
300
350
Invariant Mass
Invariant mass is a measure of the pT of the leptonfrom W decay and the soft muon within the b-jet.
1Invariant Mass
10
GeV
0 50 100 150 200 250
Entries
0
50
100
150
200
250
300
350
Invariant Mass
Invariant mass is a measure of the pT of the leptonfrom W decay and the soft muon within the b-jet.
1Invariant Mass
10
GeV
0 50 100 150 200 250
Entries
0
50
100
150
200
250
300
350
Invariant Mass
Invariant mass is a measure of the pT of the leptonfrom W decay and the soft muon within the b-jet.
1Invariant Mass
10
GeV
0 50 100 150 200 250
Entries
0
50
100
150
200
250
300
350
Invariant Mass
Invariant mass is a measure of the pT of the leptonfrom W decay and the soft muon within the b-jet.
μ
InvMass
There is a correlation between the mass of the top quark and the invariant mass of its decay products. It’s not possible to get
a handle on the neutrino but the hard lepton from W decay and the soft muon
are accessible.
These decay products will carry a significant fraction of the original Top mass with them and from this it is possible to get
a handle on the Top mass.
1
• v13 Fullsim & v14 AtlfastII
7
1Event Selection electron channel
8
Version 13
Version 14
NJets: Total 0 1 2 3 4 5 6 >=7
v13 Initial: 25000 630 3417 7493 7548 4107 1394 310 101
Electron Pt>25 GeV: 16259 419 2237 4858 4910 2678 887 207 63
Good Electron: 5950 151 827 1785 1777 971 337 75 27
No. Electron ==1: 4634 108 692 1484 1364 714 213 38 18
MEt>20GeV: 4236 103 645 1363 1233 648 188 36 17
Njets ! 3: 2125 0 0 0 1233 648 188 36 17
HT>200GeV : 2075 0 0 0 1183 648 188 36 17
!1 SLT jets: 183 0 0 0 72 75 23 9 4
SLT Ratio !0.7: 114 0 0 0 72 32 4 4 2
NJets: Total 0 1 2 3 4 5 6 >=7
v13 Initial: 25000 630 3417 7493 7548 4107 1394 310 101
Muon Pt>20 GeV: 8822 228 1147 2693 2680 1461 490 94 29
Good muon: 7224 191 942 2203 2187 1191 416 75 19
No. Muon==1: 5065 136 705 1631 1603 717 208 47 8
MEt>20GeV: 4614 123 650 1486 1451 654 187 45 8
Njets ! 3: 2355 0 0 0 1451 654 187 45 8
HT>200GeV : 2256 0 0 0 1352 654 187 45 8
!1 SLT jets: 186 0 0 0 85 75 19 5 2
SLT Ratio !0.7: 135 0 0 0 85 43 7 0 0
NJets: Total 0 1 2 3 4 5 6 >=7
v14 Initial: 25000 654 3082 7028 7797 4368 1545 406 120
Electron Pt>25 GeV: 18669 502 2304 5206 5814 3278 1189 287 89
Good Electron: 6006 157 739 1693 1883 1046 365 95 28
No. Electron ==1: 5215 134 680 1560 1660 817 266 74 16
MEt>20GeV: 4780 120 631 1441 1525 734 240 66 15
Njets ! 3: 2588 0 0 0 1525 734 240 66 15
HT>200GeV : 2530 0 0 0 1467 734 240 66 15
!1 SLT jets: 192 0 0 0 79 71 30 10 2
SLT Ratio !0.7: 126 0 0 0 79 35 10 1 1
NJets: Total 0 1 2 3 4 5 6 >=7
v14 Initial: 25000 654 3082 7028 7797 4368 1545 406 120
Muon Pt>20 GeV: 8607 228 1062 2354 2723 1525 526 140 49
Good muon: 7109 180 880 1955 2229 1292 428 110 35
No. Muon==1: 6213 177 861 1881 1945 957 288 78 16
MEt>20GeV: 5718 161 801 1727 1793 873 266 72 15
Njets ! 3: 3029 0 0 0 1793 873 266 72 15
HT>200GeV : 2925 0 0 0 1689 873 266 72 15
!1 SLT jets: 243 0 0 0 92 98 37 10 4
1Event Selection muon channel
9
Version 13
Version 14
NJets: Total 0 1 2 3 4 5 6 >=7
v13 Initial: 25000 630 3417 7493 7548 4107 1394 310 101
Electron Pt>25 GeV: 16259 419 2237 4858 4910 2678 887 207 63
Good Electron: 5950 151 827 1785 1777 971 337 75 27
No. Electron ==1: 4634 108 692 1484 1364 714 213 38 18
MEt>20GeV: 4236 103 645 1363 1233 648 188 36 17
Njets ! 3: 2125 0 0 0 1233 648 188 36 17
HT>200GeV : 2075 0 0 0 1183 648 188 36 17
!1 SLT jets: 183 0 0 0 72 75 23 9 4
SLT Ratio !0.7: 114 0 0 0 72 32 4 4 2
NJets: Total 0 1 2 3 4 5 6 >=7
v13 Initial: 25000 630 3417 7493 7548 4107 1394 310 101
Muon Pt>20 GeV: 8822 228 1147 2693 2680 1461 490 94 29
Good muon: 7224 191 942 2203 2187 1191 416 75 19
No. Muon==1: 5065 136 705 1631 1603 717 208 47 8
MEt>20GeV: 4614 123 650 1486 1451 654 187 45 8
Njets ! 3: 2355 0 0 0 1451 654 187 45 8
HT>200GeV : 2256 0 0 0 1352 654 187 45 8
!1 SLT jets: 186 0 0 0 85 75 19 5 2
SLT Ratio !0.7: 135 0 0 0 85 43 7 0 0
NJets: Total 0 1 2 3 4 5 6 >=7
v14 Initial: 25000 654 3082 7028 7797 4368 1545 406 120
Electron Pt>25 GeV: 18669 502 2304 5206 5814 3278 1189 287 89
Good Electron: 6006 157 739 1693 1883 1046 365 95 28
No. Electron ==1: 5215 134 680 1560 1660 817 266 74 16
MEt>20GeV: 4780 120 631 1441 1525 734 240 66 15
Njets ! 3: 2588 0 0 0 1525 734 240 66 15
HT>200GeV : 2530 0 0 0 1467 734 240 66 15
!1 SLT jets: 192 0 0 0 79 71 30 10 2
SLT Ratio !0.7: 126 0 0 0 79 35 10 1 1
NJets: Total 0 1 2 3 4 5 6 >=7
v14 Initial: 25000 654 3082 7028 7797 4368 1545 406 120
Muon Pt>20 GeV: 8607 228 1062 2354 2723 1525 526 140 49
Good muon: 7109 180 880 1955 2229 1292 428 110 35
No. Muon==1: 6213 177 861 1881 1945 957 288 78 16
MEt>20GeV: 5718 161 801 1727 1793 873 266 72 15
Njets ! 3: 3029 0 0 0 1793 873 266 72 15
HT>200GeV : 2925 0 0 0 1689 873 266 72 15
!1 SLT jets: 243 0 0 0 92 98 37 10 4
1Njets and Scalar HTv13 and v14
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Njets for events == 1 good lepton
Njets0 2 4 6 8 10 12 14 16 18 20
Sc
ale
d E
ntr
ies
0
200
400
600
800
1000
1200
1400
v13_Njets_passEntries 9693
Mean 0.01894± 4.014
v14_Njets_passEntries 11419
Mean 0.01962± 4.126
v13 Njets
v14 Njets
Scalar HT for njets > 3
GeV
0 100 200 300 400 500 600 700 800 900 1000
Sc
ale
d E
ntr
ies
0
20
40
60
80
100
120
140
160
180
200
v13_htEntries 4474
Mean 2.204± 381.2
v14_htEntries 5608
Mean 2.204± 383.7
v13 HT
v14 HT
1Electron and Muon Ptv13 and v14
11
“Good” Leptons that have passed the required cuts.
GeV
0 20 40 60 80 100 120 140
Scale
d E
ntr
ies
0
50
100
150
200
250
300
v13_ElePt_passEntries 6258
Mean 0.3955± 57.51
v14_ElePt_passEntries 6237
Mean 0.3914± 58.11
v13 Electron Pt
v14 Electron Pt
GeV
0 20 40 60 80 100 120 140 160 180 200
Sc
ale
d E
ntr
ies
0
20
40
60
80
100
120
140
160
180
200
220
240
v13_MuonPt_passEntries 7569
Mean 0.4655± 56.05
v14_MuonPt_passEntries 7443
Mean 0.4512± 55.87
v13 Muon Pt
v14 Muon Pt
1Muon and Electron Isolation Energyv13 and v14
12
Isolation energy in cone 0.20 for muons and electrons above the pt cut.
GeV
-10 0 10 20 30 40 50 60
Sc
ale
d E
ntr
ies
0
500
1000
1500
2000
2500
v13_MuonIso2_gm
Entries 9192
Mean 0.1484± 4.945
v14_MuonIso2_gm
Entries 8980
Mean 0.144± 4.734
v13 Muon Iso2
v14 Muon Iso2
GeV
-10 0 10 20 30 40 50 60
Scale
d E
ntr
ies
0
500
1000
1500
2000
2500
3000
3500
4000
v13_EIso2Entries 6258
Mean 0.03083± 2.702
v14_EIso2Entries 6237
Mean 0.008429± 0.7654
v13 Electron Iso2
v14 Electron Iso2
1Soft Lepton dRv13 and v14
13
dR between the tagged soft lepton and the lepton from W.
dR
0 1 2 3 4 5 6
Scale
d E
ntr
ies
0
2
4
6
8
10
12
14
16
18
20
22
24
v13_SLT_dREntries 369
Mean 0.05544± 2.399
v14_SLT_dREntries 434
Mean 0.05813± 2.417
v13 SLT dR
v14 SLT dR
1What’s Next?
14
AtlfastII
• More generation of events• Generate different top masses• Using the L1 trigger which *should* now work
Analysis
• Look into the soft lepton tagging code
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