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

10

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