multi-lepton Þnal states · associated production of a higgs boson and a top quark pair(tt̄h)...
TRANSCRIPT
Nihal BRAHIMIa, b, Jun GUOb, Kun LIUa, b,Emmanuel MONNIERc, Chenliang WANGb, c
aTsung − Dao Lee InstitutebShanghai Jiao Tong University
cCentre de Physique des Particules de Marseille
04 June, 2020
Analysis of ttW̄/ttH̄ production in multi-lepton final states
- Status Report -
22
Introduction
Chenliang Wang
2
Status Report 04 June, 2020
Associated Production of a Higgs Boson and a Top Quark Pair(tt̄H) allows
direct measurement of the Higgs-top Yukawa coupling, the strongest in the
SM, at tree level.
Multi-lepton final states have very high sensitivity with Higgs decaying to
and . A search for tt̄H production in ML final states has been
performed with 80 , ATLAS-CONF-2019-045
Mis-modelling of tt̄W observed:
Pre-fit excess in ≥2 b-jets events
A normalisation factor of 1.2 is applied on top of the CERN Yellow Reports
4 cross section for tt̄W
This is why the tt̄W cross sections needs to be measured first.
Two publications: tt̄W late of 2020, tt̄H summer of 2021
VV * τ+τ−
fb−1
l+l+
33
Analysis Framework
Chenliang Wang
3
Status Report 04 June, 2020
GroupFrameWork1
New framework based on Analysis Top, AT 21.2.115
HIGG8D1 derivation as the inputs, AtlasDerivation 21.2.93.0
- Updated B-tagging algorithm，RNN τhad ID，PFlow jets，
- Multiple AntiKt4Truth* collections, new PromptLeptonVeto training tool
New OverlapRemove(OR SUSY)
Two group production rounds took place (v02 and v03)
- Data/MC comparisons will be shown for v02 and v03.
GroupFrameWork2
Produces skimmed tuples out of GFW1 output
Keeping events passing a baseline selection
Keeping only the variables needed for analysis
Allows to compute additional variables
Kirill Grevtsov
SUSY OR. Peter Falke
44
Selections
Chenliang Wang
4
03 June, 2020
Preselection: events passing dilepton triggers with ≥ 2 jets and ≥ 1 b-tag @70% WP (v02)
jets: pT >25GeV and |η|<2.5
electrons: pT > 5 GeV, LooseLH, no isolation
muons: pT > 5 GeV, Medium quality, |η| < 2.7, no isolation
Analysis channels will be determined in the future, according to number and flavor of charged
leptons candidates after the preselection.
The data/MC comparison in the following pages focuses on the 2 same-sign light lepton category
V02 —> V03 updates:
- Derivation: new PLV scores for electrons and muons, more truth jet collections
- GFW1: updated leptons baseline cuts(lepton pT > 10 GeV, FCLoose isolation, muon Loose
quality, etc.)
Status Report
55
Data/MC comparisons, FullRun2: N jets, N Bjets, Leading Lepton Pt
Chenliang Wang
5
04 June, 2020
V02
V03
N Bjets Leading Lep Pt
0.5� 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5
b-jetsN
0.50.91.31.7
Dat
a / P
red. 0
500
1000
1500
2000
2500
3000
3500Even
ts
ATLAS Internal-1 = 13 TeV, 138.8 fbs
ttWML2lSS0τ inclPre-Fit
DataWttHtt*LZ/tt
Othertt
TotalUncertainty
3070.0732.4212.1212.9480.7
1084.12722.2
0 1 2 3 4 5 6 7 8
jetsN
0.50.91.31.7
Dat
a / P
red. 0
200
400
600
800
1000
1200
1400Even
ts
ATLAS Internal-1 = 13 TeV, 138.8 fbs
ttWML2lSS0τ inclPre-Fit
DataWttHtt*LZ/tt
Othertt
TotalUncertainty
3070.0732.4212.1212.9480.7
1084.12722.2
50 100 150 200 250 300 350 400 [GeV]
TLeading lep p
0.50.91.31.7
Dat
a / P
red. 1
10
210
310
410
Even
ts
ATLAS Internal-1 = 13 TeV, 138.8 fbs
ttWML2lSS0τ inclPre-Fit
DataWttHtt*LZ/tt
Othertt
TotalUncertainty
3070.0732.4212.1212.9480.7
1084.12722.2
N jets
MC underestimates data, since ttW norm not scaled up, missing of some background V03 has better agreement in general, compared with v02(Status report, Nihal).
Status Report
66
Data/MC comparisons split by year: N jets
Chenliang Wang
6
0 1 2 3 4 5 6 7 8
jetsN
0.50.91.31.7
Dat
a / P
red. 0
50
100
150
200
250
300
350
400
Even
ts
ATLAS Internal-1 = 13 TeV, 36.1 fbs
ttWML2lSS0τ inclPre-Fit
DataWttHtt*LZ/tt
Othertt
TotalUncertainty
850.0197.857.547.4
127.2294.9724.8
0 1 2 3 4 5 6 7 8
jetsN
0.50.91.31.7
Dat
a / P
red. 0
50
100
150
200
250
300
350
400
450Even
ts
ATLAS Internal-1 = 13 TeV, 43.8 fbs
ttWML2lSS0τ inclPre-Fit
DataWttHtt*LZ/tt
Othertt
TotalUncertainty
949.0228.165.970.8
147.6329.5842.0
0 1 2 3 4 5 6 7 8
jetsN
0.50.91.31.7
Dat
a / P
red. 0
100
200
300
400
500
600Even
ts
ATLAS Internal-1 = 13 TeV, 58.9 fbs
ttWML2lSS0τ inclPre-Fit
DataWttHtt*LZ/tt
Othertt
TotalUncertainty
1271.0306.574.794.7
205.9459.7
1141.5
04 June, 2020
V02
V03
2017 20182015-2016
Status Report
Similar trend among the data taking periods. Consistent results between v02 and v03.
77
Data/MC comparisons: N Bjets
Chenliang Wang
7
0.5� 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5
b-jetsN
0.50.91.31.7
Dat
a / P
red. 0
200
400
600
800
1000
1200
1400
1600
Even
ts
ATLAS Internal-1 = 13 TeV, 58.9 fbs
ttWML2lSS0τ inclPre-Fit
DataWttHtt*LZ/tt
Othertt
TotalUncertainty
1271.0306.574.794.7
205.9459.7
1141.5
0.5� 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5
b-jetsN
0.50.91.31.7
Dat
a / P
red. 0
200
400
600
800
1000
Even
ts
ATLAS Internal-1 = 13 TeV, 43.8 fbs
ttWML2lSS0τ inclPre-Fit
DataWttHtt*LZ/tt
Othertt
TotalUncertainty
949.0228.165.970.8
147.6329.5842.0
0.5� 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5
b-jetsN
0.50.91.31.7
Dat
a / P
red. 0
200
400
600
800
1000Even
ts
ATLAS Internal-1 = 13 TeV, 36.1 fbs
ttWML2lSS0τ inclPre-Fit
DataWttHtt*LZ/tt
Othertt
TotalUncertainty
850.0197.857.547.4
127.2294.9724.8
04 June, 2020
V02
V03
2017 20182015-2016
Status Report
Similar trend among the data taking periods. Consistent results between v02 and v03.
88
Data/MC comparisons: Leading lepton Pt
Chenliang Wang
8
04 June, 2020
50 100 150 200 250 300 350 400 [GeV]
TLeading lep p
0.50.91.31.7
Dat
a / P
red. 1
10
210
310
410Even
ts
ATLAS Internal-1 = 13 TeV, 43.8 fbs
ttWML2lSS0τ inclPre-Fit
DataWttHtt*LZ/tt
Othertt
TotalUncertainty
949.0228.165.970.8
147.6329.5842.0
50 100 150 200 250 300 350 400 [GeV]
TLeading lep p
0.50.91.31.7
Dat
a / P
red. 1
10
210
310
410Even
ts
ATLAS Internal-1 = 13 TeV, 36.1 fbs
ttWML2lSS0τ inclPre-Fit
DataWttHtt*LZ/tt
Othertt
TotalUncertainty
850.0197.857.547.4
127.2294.9724.8
50 100 150 200 250 300 350 400 [GeV]
TLeading lep p
0.50.91.31.7
Dat
a / P
red. 1
10
210
310
410Even
ts
ATLAS Internal-1 = 13 TeV, 58.9 fbs
ttWML2lSS0τ inclPre-Fit
DataWttHtt*LZ/tt
Othertt
TotalUncertainty
1271.0306.574.794.7
205.9459.7
1141.5
V02
V03
2017 20182015-2016
Status Report
Different trend between 2015-2016 and 2017-2018. Consistent results between v02 and v03.
99
Summary
Chenliang Wang
9
04 June, 2020
Two sets of productions were compared and they show consistent results.
The team is already planning for v04 production: Forward Jet Vertex Tagger, QG tagging, etc.
Better understanding of complex fake background for more robust estimation will be the key. Contribute
to the fake lepton background study(Matrix Method).
Thanks!Status Report
1010
Backup - Matrix method
Chenliang Wang
10
04 June, 2020
Definition of baseline loose leptons and tight leptons.
The matrix equation of the method .
Fake electron truth origin fractions in tt ̄ + tt ̄γ events
Status Report