Statistical Evaluation of the Search for Associated ...ekp-invenio.physik.uni-karlsruhe.de/record/48541/files/EKP-2014-00052.pdfEvent Selection Event topology: 4 b quarks 1 isolated

INSTITUT FUR EXPERIMENTELLE KERNPHYSIK

Statistical Evaluation of the Search for Associated Production of a Higgs

Boson and a Single Top Quark at the CMS ExperimentDPG Fruhjahrstagung Mainz 2014Ch. Boser, Th. Chwalek, N. Faltermann, Simon Fink, B. Maier, Th. Muller, J. Wagner-Kuhr | 25.03.2014

KIT – University of the State of Baden-Wuerttemberg and

National Laboratory of the Helmholtz Association

www.kit.edu

http://www.kit.edu

Introduction

Follow up talk to Benedikt Maier (T 62.2) and ChristianBoser (T 62.6)

search for Higgs production in association with a singletop quark

focus on H → bb channel

analysis is still blinded, so no observed limits today

q

g

q′

b

b

b

b

`+

ν

W

b

tH

W

Topics of this talk:classification MVAsystematic uncertainties(expected) limit setting

Simon Fink Statistical Evaluation in Single Top+Higgs 25.03.2014 2/14

Event Selection

Event topology:4 b quarks1 isolated lepton1 light forward jet

q

g

q′

b

b

b

b

`+

ν

W

b

tH

W

Defined 2 signal regions:3 tag region

3 b-tags (CSVT)

# jets ≥ 4exactly onemuon/electron

4 tag region4 b-tags (CSVT)

# jets ≥ 5exactly onemuon/electron

Additional control regiontt control region

2 b-tags (CSVT)

# jets = 4


Yields

Yields in the 4 analysis bins

Integrated Luminosity of 19.7fb−1

Muon Channel

Process 3T 4T

t t 1302 50.3single top 51 0.2t tH 14 2.0Electroweak 42 0.0

Σ backgrounds 1408 52.5

tH (κt = −1) 8 0.9S / B ratio 0.6% 1.7%

Electron Channel

Process 3T 4T

t t 895 30.5single top 37 0.7t tH 10 1.6Electroweak 8 20.5

Σ backgrounds 950 53.3

tH (κt = −1) 5 0.6S / B ratio 0.6% 1.1%


Signal extraction - MVA

MVA tool is used to separate signalfrom background3 different input variable classes:

tH reconstruction dependent variablestt reconstruction dependent variablesglobal variables

Signal enriched phase space

tH reconstruction ttbar reconstruction

tH variables ttbar variables global variables

final MVA discriminator tH vs background

fit on MVA output

'

&

$

%MVA is trained in 3T bin against all backgrounds

Currently the MLP method of TMVA is used


MVA - tH variables g

tH reconstruction dependent inputvariables:

cosθ∗

∆R(j1,H ,j2,H )

|η(light jet)|

# b-tags of Higgs jets

log pT (Higgs)

log pT (light jet)

tH variables

))top

,q2top

(q1ηmax(0 1 2 3 4 50

0.05

0.1

)btHq(b

background

=8 TeVs

)b)H(bνµt(b3T Region

=125 GeVH

=-1, mtκ

Work in progress

3T, µ

# b-tags of Higgs jets0 1 20

0.2

0.4

0.6

0.8 )btHq(b

background

=8 TeVs


=125 GeVH

=-1, mtκ

Work in progress

3T, µ

(light jet)|η|0 1 2 3 4 50

0.05

0.1

)btHq(b

background

=8 TeVs


=125 GeVH

=-1, mtκ

Work in progress

3T, µ


MVA - ttbar variables g

tt reconstruction dependent inputvariables:

jet charge(bthad )* lep. charge

∆R(jq1,jq2)

log(m(thad )−m(Wthad ))

log m(thad )

|max(ηq1,ηq2)|log(max(m(b,q1),m(b,q2)))

# jets from Wthad

with b-tag

ttbar variables

log tt_MaxMass_BTopHadLight4 4.5 5 5.50

0.05

0.1

0.15

)btHq(b

background

=8 TeVs


=125 GeVH

=-1, mtκ

Work in progress

3T, µ

) * lepton chargehadt

jet charge (b-1 -0.5 0 0.5 10

0.05

0.1

0.15)btHq(b

background

=8 TeVs


=125 GeVH

=-1, mtκ

Work in progress

3T, µ

)hadW-m

hadtlog(m

4 4.5 50

0.05

0.1

0.15

)btHq(b

background

=8 TeVs


=125 GeVH

=-1, mtκ

Work in progress

3T, µ


MVA - global variables

global input variables:

lepton charge

log 6ET

log pT (leading jet)

Sphericity

log(√

s)

global variables

sphericity0 0.05 0.1 0.15 0.20

0.05

0.1

0.15

)btHq(b

background

=8 TeVs


=125 GeVH

=-1, mtκ

Work in progress

3T, µ

(1. jet)T

log p3 4 5 6 7 80

0.1

0.2

)btHq(b

background

=8 TeVs


=125 GeVH

=-1, mtκ

Work in progress

3T, µ

slog

5.5 6 6.5 7 7.5 80

0.05

0.1)btHq(b

background

=8 TeVs


=125 GeVH

=-1, mtκ

Work in progress

3T, µ


MVA - validation g

MVA shows good separation

no noticeable overtraining

good agreement between data and MCin tt CR final MVA discriminator

tH vs background

MVA output-1 -0.5 0 0.5 10

0.05

0.1

0.15

0.2

)btHq(b

background

=8 TeVs


=125 GeVH

=-1, mtκ

Work in progress

3T, µ

NN output-1 -0.5 0 0.5 1

even

ts

0

2000

4000

6000

data

)btH(b

tt

tSingle t/

ttH

Electroweak

TH-madgraph-Summer12

MC stat.

=8 TeVs -1L=19.7 fb

)b)H(bνµt(b CRtt

NN output-1 -0.5 0 0.5 1

data

(dat

a-m

c)

-0.4-0.2

00.20.4

MC stat.

Work in progress

tt CR, µ


Final MVA Classifier g

Classification weights applied to two analysisbins in two lepton channels

MVA output transformed from −1 to 1 in 15 binsto ensure enough MC events in outer bins

CLs Limits are currently calculated by fitting thewhole range with THETA package

fit on MVA output

MVA output-1 -0.5 0 0.5 1

even

ts

0

100

200

300data

)btH(b

tt

tSingle t/

ttH

Electroweak

(TH-madgraph-Summer12)σ50x

MC stat.

=8 TeVs -1L=19.7 fb


=125 GeVH

=-1, mtκ

MVA output-1 -0.5 0 0.5 1

data

(dat

a-m

c)

-0.4-0.2

00.20.4

MC stat.

3T, µ

Work in progress

MVA output-1 -0.5 0 0.5 1

even

ts

0

5

10

15 data

)btH(b

tt

tSingle t/

ttH

Electroweak

(TH-madgraph-Summer12)σ15x

MC stat.

=8 TeVs -1L=19.7 fb


=125 GeVH

=-1, mtκ

MVA output-1 -0.5 0 0.5 1

data

(dat

a-m

c)

-1

-0.5

0

0.5

1MC stat.

4T, µ

Work in progress


Shapes for different systematics

Considering rate and shape systematics for all processes

MVA output-1 -0.5 0 0.5 1

Eve

nts

0

0.05

0.1

0.15

=8 TeVs -1L=19.7 fb

), 3T Regionb)H(bνt(bl

=H

=-1, mtκ 125 GeV

systematicsJER

Nominal

Up

Down

Work in progress

JER, tHq

MVA output-1 -0.5 0 0.5 1

Eve

nts

0

0.05

0.1

0.15

=8 TeVs -1L=19.7 fb


=H

=-1, mtκ "125"GeV

Nominal

Up

Down

Work in progress

PU, tHq

MVA output-1 -0.5 0 0.5 1

Eve

nts

0

0.05

0.1

0.15

=8 TeVs -1L=19.7 fb


=H

=-1, mtκ 125 GeV

systematicsJES

Nominal

Up

Down

JES, tHq

Work in progress

MVA output-1 -0.5 0 0.5 1

Eve

nts

0

0.05

0.1

0.15

=8 TeVs -1L=19.7 fb


=H

=-1, mtκ GeV

Nominal

Up

Down

Work in progress

Top pT,tt


Impact of different Uncertainties

Studied influence of different systematic uncertainties for the MCapproachTwo different approaches:

Without systematics, only taking one systematic into accountFull systematics, only taking one systematic out at a time

Systematic Sourceeffect on limit

only source without source

Pile Up −6.44% +0.26%BTag +15.62% +1.39%Mistag +1.24% −0.38%JES +10.40% −0.48%JER −5.47% −0.55%Unclustered Energy −0.43% −2.36%Cross sections +13.59% −5.73%Lepton Efficiency +2.37% +3.92%Luminosity +5.16% −6.72%Matching +0.55% +0.29%

Q2 scale +1.48% −0.65%Top pT reweighting +5.70% +4.61%

b tag rate, luminosity and cross section uncertainties have the largestimpact on the final limit


Expected Limits for tHq(H → bb) - MCbased approach

comb 3T 4T

= -

1tκσ/σ

lim

it on

S

95%

C.L

. CL

0

10

20

30 = 8 TeVs -1L = 19.7 fb

tHq production→pp b b→, H ν bl→t

= 125 GeVH

= -1, mtκ

expectedsCL

exp.s CLσ 1±

exp.s CLσ 2±

Work in progress

95% CLs [σ/σpred ]

3 tag 8.004 tag 12.24

Comb. 5.89

Can exclude tH with anomalous coupling with ≈ 5× expected cross section

limit is driven by 3 tag bin

recent studies show ∼ 20% improvement is reachable with CSV variablesas input variables


Outlook & future plans

Short TermGet ready to unblind!Be on our toes for sensitivity improvements

Long TermWait for new and more dataSearch for SM coupling with κt = +1


BACKUP


Classification Input variables - Electronchannel I (scaled to eq. area)

Lepton_Charged-1 0 10

5000

10000

15000

data)btH(b

tttSingle t/

ttHElectroweakMC stat.

=8 TeVs -1L=19.3 fb

)b)H(bνt(be CRtt


data

(dat

a-m

c)

-0.001

0

0.001MC stat.

Work in progress

)sln(

5 6 7 8 9 100

2000

4000

data)btH(b

tttSingle t/


=8 TeVs -1L=19.3 fb

)b)H(bνt(be CRtt

)sln(5 6 7 8 9 10

data

(dat

a-m

c)

-0.5

0

0.5 MC stat.

Work in progress

1. jet)T

ln(P3 4 5 6 7 80

2000

4000

6000 data)btH(b

tttSingle t/


=8 TeVs -1L=19.3 fb

)b)H(bνt(be CRtt

1. jet)T

ln(P3 4 5 6 7 8

data

(dat

a-m

c)

-0.5

0

0.5MC stat.

Work in progress

log(MET)0 2 4 6 80

5000

10000data

)btH(btt

tSingle t/ttHElectroweakMC stat.

=8 TeVs -1L=19.3 fb

)b)H(bνt(be CRtt

log(MET)0 2 4 6 8

data

(dat

a-m

c)

-0.5

0

0.5 MC stat.

Work in progress

Higgs)T

ln(P0 2 4 60

2000

4000

6000data

)btH(btt


=8 TeVs -1L=19.3 fb

)b)H(bνt(be CRtt

Higgs)T

ln(P0 2 4 6

data

(dat

a-m

c)

-1

-0.5

0

0.5

1MC stat.

Work in progress

Recoil)T

ln(P3 4 5 6 70

1000

2000

3000

data)btH(b

tttSingle t/


=8 TeVs -1L=19.3 fb

)b)H(bνt(be CRtt

Recoil)T

ln(P3 4 5 6 7

data

(dat

a-m

c)

-0.2

0

0.2 MC stat.

Work in progress

Cos LepRecoil-1 -0.5 0 0.5 10

500

1000

1500 data)btH(b

tttSingle t/


=8 TeVs -1L=19.3 fb

)b)H(bνt(be CRtt


data

(dat

a-m

c)

-0.2

-0.1

0

0.1

0.2MC stat.

Work in progress

|Recoil

η|0 1 2 3 4 50

500

1000

1500

2000

data)btH(b

tttSingle t/


=8 TeVs -1L=19.3 fb

)b)H(bνt(be CRtt

|Recoil

η|0 1 2 3 4 5

data

(dat

a-m

c)

-5

0

5 MC stat.

Work in progress


Classification Input variables - Electronchannel II (scaled to eq. area)

Sphericity0 0.05 0.1 0.15 0.20

1000

2000

data)btH(b

tttSingle t/


=8 TeVs -1L=19.3 fb

)b)H(bνt(be CRtt

Sphericity0 0.05 0.1 0.15 0.2

data

(dat

a-m

c)

-0.5

0

0.5 MC stat.

Work in progress

)top

,q2top

(q1ηmax(0 1 2 3 4 50

1000

2000

3000data

)btH(btt


=8 TeVs -1L=19.3 fb

)b)H(bνt(be CRtt

)top

,q2top

(q1ηmax(0 1 2 3 4 5

data

(dat

a-m

c)

-2

-1

0

1

2MC stat.

Work in progress

)hadt

ln(m4 5 6 7 80

5000

10000

data)btH(b

tttSingle t/


=8 TeVs -1L=19.3 fb

)b)H(bνt(be CRtt

)hadt

ln(m4 5 6 7 8

data

(dat

a-m

c)

-0.5

0

0.5MC stat.

Work in progress

)hadW-m

hadtln(m

3 4 5 6 7 80

5000

10000

data)btH(b

tttSingle t/


=8 TeVs -1L=19.3 fb

)b)H(bνt(be CRtt

)hadW-m

hadtln(m

3 4 5 6 7 8

data

(dat

a-m

c)

-1

0

1 MC stat.

Work in progress

ln(tt_MaxMass_BTopHadLight)4 5 6 7 80

5000

10000data

)btH(btt


=8 TeVs -1L=19.3 fb

)b)H(bνt(be CRtt


data

(dat

a-m

c)

-1

0

1MC stat.

Work in progress

# btags of Higgs jets0 0.5 1 1.5 20

10000

20000

30000 data)btH(b

tttSingle t/


=8 TeVs -1L=19.3 fb

)b)H(bνt(be CRtt


data

(dat

a-m

c)

-0.05

0

0.05MC stat.

Work in progress

jetshad

# btags of Top0 0.5 1 1.5 20

10000

20000

30000

data)btH(b

tttSingle t/


=8 TeVs -1L=19.3 fb

)b)H(bνt(be CRtt

jetshad

# btags of Top0 0.5 1 1.5 2

data

(dat

a-m

c)

-0.1

-0.05

0

0.05

0.1MC stat.

Work in progress

)Higgs

,jHiggs

R(j∆0 1 2 3 4 50

1000

2000

3000

data)btH(b

tttSingle t/


=8 TeVs -1L=19.3 fb

)b)H(bνt(be CRtt

)Higgs

,jHiggs

R(j∆0 1 2 3 4 5

data

(dat

a-m

c)

-1-0.5

00.5

1MC stat.

Work in progress

jets)had

R(Top∆0 1 2 3 4 50

1000

2000

3000 data)btH(b

tttSingle t/


=8 TeVs -1L=19.3 fb

)b)H(bνt(be CRtt

jets)had

R(Top∆0 1 2 3 4 5

data

(dat

a-m

c)

-0.5

0

0.5 MC stat.

Work in progress

SumCharge_light-1 0 10

1000

2000

3000 data)btH(b

tttSingle t/


=8 TeVs -1L=19.3 fb

)b)H(bνt(be CRtt


data

(dat

a-m

c)

-0.2-0.1

00.10.2

MC stat.

Work in progress


Classification Input variables - Muonchannel I (scaled to eq. area)


10000

20000

data)btH(b

tttSingle t/


=8 TeVs -1L=19.3 fb

)b)H(bνµt(b CRtt


data

(dat

a-m

c)

-0.001

0

0.001 MC stat.

Work in progress

)sln(

5 6 7 8 9 100

2000

4000

6000

data)btH(b

tttSingle t/


=8 TeVs -1L=19.3 fb

)b)H(bνµt(b CRtt

)sln(5 6 7 8 9 10

data

(dat

a-m

c)

-5

0

5MC stat.

Work in progress

1. jet)T

ln(P3 4 5 6 7 80

2000

4000

6000

8000data

)btH(btt


=8 TeVs -1L=19.3 fb

)b)H(bνµt(b CRtt

1. jet)T

ln(P3 4 5 6 7 8

data

(dat

a-m

c)

-0.5

0

0.5 MC stat.

Work in progress

log(MET)3 4 5 6 7 80

2000

4000

6000

data)btH(b

tttSingle t/


=8 TeVs -1L=19.3 fb

)b)H(bνµt(b CRtt

log(MET)3 4 5 6 7 8

data

(dat

a-m

c)

-1

0

1 MC stat.

Work in progress

Higgs)T

ln(P0 2 4 60

2000

4000

6000

8000

data)btH(b

tttSingle t/


=8 TeVs -1L=19.3 fb

)b)H(bνµt(b CRtt

Higgs)T

ln(P0 2 4 6

data

(dat

a-m

c)

-0.5

0

0.5MC stat.

Work in progress

Recoil)T

ln(P3 4 5 6 70

1000

2000

3000

4000

data)btH(b

tttSingle t/


=8 TeVs -1L=19.3 fb

)b)H(bνµt(b CRtt

Recoil)T

ln(P3 4 5 6 7

data

(dat

a-m

c)

-0.5

0

0.5MC stat.

Work in progress


500

1000

1500

2000 data)btH(b

tttSingle t/


=8 TeVs -1L=19.3 fb

)b)H(bνµt(b CRtt


data

(dat

a-m

c)

-0.1

0

0.1 MC stat.

Work in progress

|Recoil

η|0 1 2 3 4 50

1000

2000

3000data

)btH(btt


=8 TeVs -1L=19.7 fb

)b)H(bνµt(b CRtt

|Recoil

η|0 1 2 3 4 5

data

(dat

a-m

c)

-1

0

1 MC stat.

Work in progress


Classification Input variables - Muonchannel II (scaled to eq. area)

Sphericity0 0.05 0.1 0.15 0.20

1000

2000

3000

4000data

)btH(btt


=8 TeVs -1L=19.3 fb

)b)H(bνµt(b CRtt

Sphericity0 0.05 0.1 0.15 0.2

data

(dat

a-m

c)

-1

-0.5

0

0.5

1MC stat.

Work in progress

)top

,q2top

(q1ηmax(0 1 2 3 4 50

1000

2000

3000

4000

data)btH(b

tttSingle t/


=8 TeVs -1L=19.3 fb

)b)H(bνµt(b CRtt

)top

,q2top

(q1ηmax(0 1 2 3 4 5

data

(dat

a-m

c)

-5

0

5MC stat.

Work in progress

)hadt

ln(m4 5 6 7 80

5000

10000

15000

data)btH(b

tttSingle t/


=8 TeVs -1L=19.3 fb

)b)H(bνµt(b CRtt

)hadt

ln(m4 5 6 7 8

data

(dat

a-m

c)

-0.5

0

0.5 MC stat.

Work in progress

)hadW-m

hadtln(m

3 4 5 6 7 80

5000

10000

15000data

)btH(btt


=8 TeVs -1L=19.3 fb

)b)H(bνµt(b CRtt

)hadW-m

hadtln(m

3 4 5 6 7 8

data

(dat

a-m

c)

-4-2024

MC stat.

Work in progress


5000

10000

data)btH(b

tttSingle t/


=8 TeVs -1L=19.3 fb

)b)H(bνµt(b CRtt


data

(dat

a-m

c)

-2-1012

MC stat.

Work in progress


10000

20000

30000

40000 data)btH(b

tttSingle t/


=8 TeVs -1L=19.3 fb

)b)H(bνµt(b CRtt


data

(dat

a-m

c)

-0.05

0

0.05 MC stat.

Work in progress

jetshad

# btags of Top0 0.5 1 1.5 20

10000

20000

30000

40000

data)btH(b

tttSingle t/


=8 TeVs -1L=19.3 fb

)b)H(bνµt(b CRtt

jetshad

# btags of Top0 0.5 1 1.5 2

data

(dat

a-m

c)

-0.05

0

0.05 MC stat.

Work in progress

)Higgs

,jHiggs

R(j∆0 1 2 3 4 50

2000

4000

data)btH(b

tttSingle t/


=8 TeVs -1L=19.3 fb

)b)H(bνµt(b CRtt

)Higgs

,jHiggs

R(j∆0 1 2 3 4 5

data

(dat

a-m

c)

-2

0

2 MC stat.

Work in progress

jets)had

R(Top∆0 1 2 3 4 50

1000

2000

3000

4000data

)btH(btt


=8 TeVs -1L=19.3 fb

)b)H(bνµt(b CRtt

jets)had

R(Top∆0 1 2 3 4 5

data

(dat

a-m

c)

-0.2

0

0.2 MC stat.

Work in progress


1000

2000

3000

4000data

)btH(btt


=8 TeVs -1L=19.3 fb

)b)H(bνµt(b CRtt


data

(dat

a-m

c)

-0.2

0

0.2 MC stat.

Work in progress


Documents

Statistical Evaluation of the Search for Associated ...ekp-invenio.physik.uni-karlsruhe.de/record/48541/files/EKP-2014-00052.pdfEvent Selection Event topology: 4 b quarks 1 isolated