pct_DaeSymposium2020Andrew Askew[2], Raman Khurana[2], Jyothsna Rani Komaragiri[1], Deepak Kumar[1], Praveen Chandra Tiwari[1] , Shin-Shan Eiko Yu[3]
[1]Indian Institute of Science, Bangalore, India [2]Florida State University
[3]National Central University, Taiwan
DAE-BRNS HIGH ENERGY PHYSICS SYMPOSIUM 2020 14th - 18th December, 2020
Search for dark matter produced in association with b-jets
Praveen Chandra Tiwari DAE-BRNS HIGH ENERGY PHYSICS SYMPOSIUM 14th - 18th December, 2020
Introduction
2
Search for dark matter produced in association with b-jets Final state signature: The shape of the distribution to discriminate potential DM signal from SM background
The major backgrounds are: Z or W produced in association with b-jets, single top and top quark pair production.
Control regions(CRs) to model the main background of the analysis and to perform simultaneous fit with the signal region (SR) to estimate the background in SR properly
Using Hadronic recoil instead of MET in CRs, defined as:
Previous searches: 2015 bbDM analysis using 2.2 fb-1 data (CADI), Eur. Phys. J. C 77 (2017) 845 (CADI), Eur. Phys. J. C 78 (2018) 18)
bb + pmiss T
Praveen Chandra Tiwari DAE-BRNS HIGH ENERGY PHYSICS SYMPOSIUM 14th - 18th December, 2020
2HDM+a model A Model recommended by the ATLAS/CMS Dark Matter Forum
(LHCDMF) with One light(h) and one heavy(H) scalar One light(a) and one heavy(A) pseudo-scalars Two charged Higgs H± with identical mass.
For Dark Matter A lighter (a) and heavier (A) pseudo-scalar couple to standard model
and dark matter particle ( )
Coupling:
χ
Praveen Chandra Tiwari DAE-BRNS HIGH ENERGY PHYSICS SYMPOSIUM 14th - 18th December, 2020
genMET[GeV] 0 100 200 300 400 500 600 700 800 900 1000
Ev en
=100 GeVaM =200 GeVaM =300 GeVaM =400 GeVaM =500 GeVaM
genMET (GeV)
Ev en
2HDM+a Model
MA = 600 GeV tanβ = 35 sinθ = 0.707 Of all the parameters, genMET distribution is independent of MA, sinθ, tanβ, Mχ To maximise cross-section following values of the parameters has been chosen
tanβ = 35 sinθ = 0.7 Mχ = 1 GeV
For the Ma and MA <latexit sha1_base64="1kCO6WpeSyup4/GjZL7Pp3g0LzE=">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</latexit>
MA Ma
600 10 50 100 150 200 250 300 350 400 450 500 1200 10 50 100 150 200 250 300 350 400 450 500 700 750 1000
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Praveen Chandra Tiwari DAE-BRNS HIGH ENERGY PHYSICS SYMPOSIUM 14th - 18th December, 2020
Physics Objects Jets
Loose ID (Tight for 2017 and 18)
cleaning against electron and muon using ΔR (lepton,jet) < 0.4
b-Jets
DeepCSV Medium working point
5
Electrons
Loose ID
Muons
Loose ID and Isolation < 0.25
Tau
decayModeFinding and
Praveen Chandra Tiwari DAE-BRNS HIGH ENERGY PHYSICS SYMPOSIUM 14th - 18th December, 2020
Event Selection: Signal Region Events are triggered with MET based triggers for Signal Region
Two categories:
SR1: at least 1 b-tag jet, min-Δφ(jet, MET) > 0.5 for 2 total jets
SR2: at least 2 b-tag jet, min-Δφ(jet, MET) > 0.5 for 3 total jets
leading jet pT > 50 GeV
Veto on e, μ, and τ leptons
MET > 200 GeV
PFpmiss T − Calopmiss
Praveen Chandra Tiwari DAE-BRNS HIGH ENERGY PHYSICS SYMPOSIUM 14th - 18th December, 2020
Top+jets μ/e with tight ID ISO, recoil > 200 and MT < 160 ≥ 1 additional jets
7
12 Control regions are defined for this analysis using same jet selection as SR but with different lepton selection.
W+jets μ/e with tight ID ISO, recoil > 200 and MT < 160 No additional jet
> 100pmiss T
)
Z+jets CR μμ/ee with 70 < Mll < 110, recoil > 200 leading lep pT > 30 GeV with tight ID ISO
Event Selection: Control Region
Praveen Chandra Tiwari DAE-BRNS HIGH ENERGY PHYSICS SYMPOSIUM 14th - 18th December, 2020
Signal Region
200 300 400 500 600 700 800 900 1000 (GeV)miss
T p
in
2HDM+a model ma = 150 GeV, mA = 1200 GeV ma = 150 GeV, mA = 600 GeV ma = 500 GeV, mA = 1200 GeV ma = 500 GeV, mA = 600 GeV
bkgSum tt Single t )+jets νW(l WW/WZ/ZZ +jets γ
)+jets ννZ( Z(ll)+jets QCD SMH
SR(1b)SR(1b)
200 300 400 500 600 700 800 900 1000 (GeV)miss
T p
1− 0.5−
0 0.5
200 300 400 500 600 700 800 900 1000 (GeV)miss
T p
in
2HDM+a model ma = 150 GeV, mA = 1200 GeV ma = 150 GeV, mA = 600 GeV ma = 500 GeV, mA = 1200 GeV ma = 500 GeV, mA = 600 GeV
bkgSum tt Single t )+jets νW(l WW/WZ/ZZ +jets γ
)+jets ννZ( Z(ll)+jets QCD SMH
SR(2b)SR(2b)
200 300 400 500 600 700 800 900 1000 (GeV)miss
T p
1− 0.5−
0 0.5
200 300 400 500 600 700 800 900 1000 (GeV)miss
T p
in
2HDM+a model ma = 150 GeV, mA = 1200 GeV ma = 150 GeV, mA = 600 GeV ma = 500 GeV, mA = 1200 GeV ma = 500 GeV, mA = 600 GeV
bkgSum tt Single t )+jets νW(l WW/WZ/ZZ +jets γ
)+jets ννZ( Z(ll)+jets QCD SMH
SR(1b)SR(1b)
200 300 400 500 600 700 800 900 1000 (GeV)miss
T p
1− 0.5−
0 0.5
200 300 400 500 600 700 800 900 1000 (GeV)miss
T p
in 2HDM+a model
ma = 150 GeV, mA = 1200 GeV ma = 150 GeV, mA = 600 GeV ma = 500 GeV, mA = 1200 GeV ma = 500 GeV, mA = 600 GeV
bkgSum tt Single t )+jets νW(l WW/WZ/ZZ +jets γ
)+jets ννZ( Z(ll)+jets QCD SMH
SR(2b)SR(2b)
200 300 400 500 600 700 800 900 1000 (GeV)miss
T p
1− 0.5−
0 0.5
200 300 400 500 600 700 800 900 1000 (GeV)miss
T p
in
2HDM+a model ma = 150 GeV, mA = 1200 GeV ma = 150 GeV, mA = 600 GeV ma = 500 GeV, mA = 1200 GeV ma = 500 GeV, mA = 600 GeV
bkgSum tt Single t )+jets νW(l WW/WZ/ZZ +jets γ
)+jets ννZ( Z(ll)+jets QCD SMH
SR(1b)SR(1b)
200 300 400 500 600 700 800 900 1000 (GeV)miss
T p
1− 0.5−
0 0.5
200 300 400 500 600 700 800 900 1000 (GeV)miss
T p
in
2HDM+a model ma = 150 GeV, mA = 1200 GeV ma = 150 GeV, mA = 600 GeV ma = 500 GeV, mA = 1200 GeV ma = 500 GeV, mA = 600 GeV
bkgSum tt Single t )+jets νW(l WW/WZ/ZZ +jets γ
)+jets ννZ( Z(ll)+jets QCD SMH
SR(2b)SR(2b)
200 300 400 500 600 700 800 900 1000 (GeV)miss
T p
1− 0.5−
0 0.5
Work in Progress
Praveen Chandra Tiwari DAE-BRNS HIGH ENERGY PHYSICS SYMPOSIUM 14th - 18th December, 2020
Control Region
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200 300 400 500 600 700 800 900 1000 Recoil (GeV)
1
10
210
310
410
510
610
in Data tt Single t )+jets νW(l WW/WZ/ZZ +jets γ
)+jets ννZ( Z(ll)+jets QCD SMH
)+1b CRνµ(tt )+1b CRνµ(tt
CMSInternal (13 TeV)-135.82 fb
200 300 400 500 600 700 800 900 1000 Recoil (GeV)
1− 0.5−
0 0.5
1 Pr
ed D
at a-
Pr ed stat + syst
200 300 400 500 600 700 800 900 1000 Recoil (GeV)
1
10
210
310
410
510
in Data tt Single t )+jets νW(l WW/WZ/ZZ +jets γ
)+jets ννZ( Z(ll)+jets QCD SMH
)+2b CRνµ(tt )+2b CRνµ(tt
CMSInternal (13 TeV)-135.82 fb
200 300 400 500 600 700 800 900 1000 Recoil (GeV)
1− 0.5−
0 0.5
ed stat + syst
200 300 400 500 600 700 800 900 1000 Recoil (GeV)
1
10
210
310
410
510
610
in Data tt Single t )+jets νW(l WW/WZ/ZZ +jets γ
)+jets ννZ( Z(ll)+jets QCD SMH
)+1b CRνµ(tt )+1b CRνµ(tt
CMSInternal (13 TeV)-141.50 fb
200 300 400 500 600 700 800 900 1000 Recoil (GeV)
1− 0.5−
0 0.5
ed stat + syst
200 300 400 500 600 700 800 900 1000 Recoil (GeV)
1
10
210
310
410
510
in Data tt Single t )+jets νW(l WW/WZ/ZZ +jets γ
)+jets ννZ( Z(ll)+jets QCD SMH
)+2b CRνµ(tt )+2b CRνµ(tt
CMSInternal (13 TeV)-141.50 fb
200 300 400 500 600 700 800 900 1000 Recoil (GeV)
1− 0.5−
0 0.5
ed stat + syst
200 300 400 500 600 700 800 900 1000 Recoil (GeV)
1
10
210
310
410
510
610
in Data tt Single t )+jets νW(l WW/WZ/ZZ +jets γ
)+jets ννZ( Z(ll)+jets QCD SMH
)+1b CRνµ(tt )+1b CRνµ(tt
CMSInternal (13 TeV)-159.64 fb
200 300 400 500 600 700 800 900 1000 Recoil (GeV)
1− 0.5−
0 0.5
ed stat + syst
200 300 400 500 600 700 800 900 1000 Recoil (GeV)
1
10
210
310
410
510
in Data tt Single t )+jets νW(l WW/WZ/ZZ +jets γ
)+jets ννZ( Z(ll)+jets QCD SMH
)+2b CRνµ(tt )+2b CRνµ(tt
CMSInternal (13 TeV)-159.64 fb
200 300 400 500 600 700 800 900 1000 Recoil (GeV)
1− 0.5−
0 0.5
In all the Years, the Data MC agreement is good.
Similar agreement has been seen in all the other control regions i.e W and Z.
2016 2017 2018
Work in Progress
Work in Progress
Praveen Chandra Tiwari DAE-BRNS HIGH ENERGY PHYSICS SYMPOSIUM 14th - 18th December, 2020
Signal Extraction & Systematic Uncertainties
Praveen Chandra Tiwari DAE-BRNS HIGH ENERGY PHYSICS SYMPOSIUM 14th - 18th December, 2020
Uncertainties Luminosity: 2.5%
PU re-weighting: vary σinelastic by 4.6% and re-compute PU weights
b-tagging: vary according to uncertainties on BTV POG SFs
Lepton selection efficiency: 3% per lepton
Lepton trigger efficiency: 2% in 1l-regions, 1% in 2l-regions
MET trigger efficiency: 2%
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PDF: as per recommendation, using the weights saved in the MC samples.
QCD scale: vary μR, μF, up and down as per weights stored in the MC samples.
Jet Energy Scale: vary according to uncertainties in JES from JME POG V+jets
Top pT re-weighting: 50%
Praveen Chandra Tiwari DAE-BRNS HIGH ENERGY PHYSICS SYMPOSIUM 14th - 18th December, 2020
Signal Extraction We perform the signal extraction with Higgs Combine Tool
One normalisation factor for each major background
Fit performed in 4 bins of recoil.
Different for 1b and 2b categories
The limits will be calculated using these transfer factors 12
SR Wμν+jets Weν+jets Zμμ+jets Zee+jets tt (μν) tt (eν)
WJets o o
Praveen Chandra Tiwari DAE-BRNS HIGH ENERGY PHYSICS SYMPOSIUM 14th - 18th December, 202013
Search for DM in the bb+MET channel using full Run2 CMS data
We have well modelled the background of the analysis:
with good Data-MC agreement all control regions.
All the systematic uncertainties for e.g btag scale factors, MET trigger scale factors and Top pT reweighting are applied in the analysis.
We use 2HDM+a model for interpretation
So far the analysis is blinded ,i.e we have not looked into data in our signal region
The analysis is going for pre-approval within the CMS, hence final results are not shown in this talk
Summary
Praveen Chandra Tiwari DAE-BRNS HIGH ENERGY PHYSICS SYMPOSIUM 14th - 18th December, 2020
Thank You