Impact of jet energy resolution on Higgs invisible decays Yu Kato - - PowerPoint PPT Presentation

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Impact of jet energy resolution on Higgs invisible decays Yu Kato - - PowerPoint PPT Presentation

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Impact of jet energy resolution on Higgs invisible decays Yu Kato The University of Tokyo ILD Meeting 2018 in Ichinoseki Feb. 22, 2018 katou@icepp.s.u-tokyo.ac.jp Outline Evaluate jet energy resolution & jet angle resolution ILD models:

slide-1
SLIDE 1

Impact of jet energy resolution on Higgs invisible decays

Yu Kato The University of Tokyo

ILD Meeting 2018 in Ichinoseki Feb. 22, 2018 katou@icepp.s.u-tokyo.ac.jp

slide-2
SLIDE 2

Outline

Evaluate jet energy resolution & jet angle resolution

ILD models: large/small Ø check jet energy ＆ cosθ dependence

Study impact on physics analysis [Higgs invisible decays with hadronic recoil]

use kinematic fit (MarlinKinfit) fit variables : mass constraint : apply jet energy/angle resolution

2018/2/22

Impact of jet energy resolution on Higgs invisible decays 2

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SLIDE 3

2018/2/22

Impact of jet energy resolution on Higgs invisible decays 3

Mark Thomson ILD meeting 2014 in Oscu

slide-4
SLIDE 4

Outline

Evaluate jet energy resolution & jet angle resolution

ILD models: large/small Ø check jet energy ＆ cosθ dependence

Study impact on physics analysis [Higgs invisible decays with hadronic recoil]

use kinematic fit (MarlinKinfit) fit variables : mass constraint : apply jet energy/angle resolution

2018/2/22

Impact of jet energy resolution on Higgs invisible decays 4

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SLIDE 5

lILCSoft : v01-19-05 (gcc49) lILDConfig : v01-19-05-p01 lILD models : ILD_l5_o1_v02, (ILD_s5_o1_v02) lSamples: Z→uds (w/o overlay) [/ilc/prod/ilc/mc-opt.dsk/ild/dst/calib/uds/… ] l Jet resolution definition

  • use RMS90 method
  • Energy

(J. S. Marshall and M. A. Thomson, ”Pandora Particle Flow Algorithm”, arXiv:1308.4537 [physics.ins-det])

  • Angle

𝜀𝜚 = RMS90(𝜚<=> − 𝜚@>) 𝜀𝜄 = RMS90(𝜄<=> − 𝜄@>)

2018/2/22

Impact of jet energy resolution on Higgs invisible decays 5

Setup of Evaluating JER

√s [GeV]

30 40 60 91 120 160 200 240 300 350 400 500 l5 [events] 10k 10k 10k 10k 10k 10k 10k 10k 9k 10k 9k 10k s5 [events] 10k 10k 10k 10k 9k 10k 10k 9k 10k 10k 10k 10k

use jet clustering: Durham

Evaluate JER

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SLIDE 6

JER: Comparison Barrel/Endcap

2018/2/22

Impact of jet energy resolution on Higgs invisible decays 6

Evaluate JER

[GeV]

j

E

50 100 150 200 250

) [%]

j

(E

90

) / Mean

j

(E

90

RMS

3 4 5 6 7

sv01-19-05.mILD_l5_o1_v02_nobg

/E = 3.5%

E

σ E /E = 30%/

E

σ Overall :

j

E

  • 1.97 +0.200

j

E 31.3/ | < 0.7 θ Barrel : |cos

j

E

  • 1.91 +0.195

j

E 28.9/ 0.7 ≥ | θ Endcap : |cos

j

E

  • 1.66 +0.184

j

E 33.6/

Endcap Overall Barrel

α β Overall 31.3

  • 1.97+0.200√E

Barrel 28.9

  • 1.91+0.195√E

Endcap 33.6

  • 1.66+0.184√E

Endcap Barrel

θ

JER was evaluated separately for barrel and endcap regions.

slide-7
SLIDE 7

[GeV]

j

E

50 100 150 200 250

) [%]

j

(E

90

) / Mean

j

(E

90

RMS

3 4 5 6 7

|<0.7 θ sv01-19-05 |cos

/E = 3.5%

E

σ E /E = 30%/

E

σ mILD_l5_o1_v02_nobg

j

E

  • 1.91 +0.195

j

E 28.9/ mILD_s5_o1_v02_nobg

j

E

  • 1.59 +0.199

j

E 27.6/

JER: Comparison Large/Small

2018/2/22

Impact of jet energy resolution on Higgs invisible decays 7

Small Large

  • Impact of small detector seen for large jet energy
  • JER goal (ILC TDR) satisfied for both models

α β Small 28.9

  • 1.91+0.195√E

Large 27.6

  • 1.59+0.199√E

The two detector models (large/small) were evaluated for comparison.

Evaluate JER

slide-8
SLIDE 8

JER: Angular Dependence

2018/2/22

Impact of jet energy resolution on Higgs invisible decays 8

| θ |cos

0.2 0.4 0.6 0.8 1

) [%]

j

(E

90

) / Mean

j

(E

90

RMS

5 10 15

sv01-19-05.mILD_l5_o1_v02_nobg

15GeV 20GeV 30GeV 45.5GeV 60GeV 80GeV 100GeV 120GeV 150GeV 175GeV 200GeV 250GeV

| θ |cos

0.2 0.4 0.6 0.8 1

) [%]

j

(E

90

) / Mean

j

(E

90

RMS

5 10 15

sv01-19-05.mILD_s5_o1_v02_nobg

15GeV 20GeV 30GeV 45.5GeV 60GeV 80GeV 100GeV 120GeV 150GeV 175GeV 200GeV 250GeV

ILD_l5_v02 ILD_s5_v02 [used as input for kinematic fit]

  • JER worse for forward jets as expected
  • Angular dependence has same tendency for large/small

Evaluate JER

slide-9
SLIDE 9

| θ |cos

0.2 0.4 0.6 0.8 1

MC

φ

  • REC

φ = φ δ

0.05 0.1 0.15 0.2 0.25 0.3

sv01-19-05.mILD_l5_o1_v02_nobg

15GeV 20GeV 30GeV 45.5GeV 60GeV 80GeV 100GeV 120GeV 150GeV 175GeV 200GeV 250GeV

| θ |cos

0.2 0.4 0.6 0.8 1

MC

φ

  • REC

φ = φ δ

0.05 0.1 0.15 0.2 0.25 0.3

sv01-19-05.mILD_s5_o1_v02_nobg

15GeV 20GeV 30GeV 45.5GeV 60GeV 80GeV 100GeV 120GeV 150GeV 175GeV 200GeV 250GeV

Angular Resolution [used as input for kinematic fit]

2018/2/22

Impact of jet energy resolution on Higgs invisible decays 9

| θ |cos

0.2 0.4 0.6 0.8 1

MC

θ

  • REC

θ = θ δ

0.02 0.04 0.06 0.08

sv01-19-05.mILD_l5_o1_v02_nobg

15GeV 20GeV 30GeV 45.5GeV 60GeV 80GeV 100GeV 120GeV 150GeV 175GeV 200GeV 250GeV

| θ |cos

0.2 0.4 0.6 0.8 1

MC

θ

  • REC

θ = θ δ

0.02 0.04 0.06 0.08

sv01-19-05.mILD_s5_o1_v02_nobg

15GeV 20GeV 30GeV 45.5GeV 60GeV 80GeV 100GeV 120GeV 150GeV 175GeV 200GeV 250GeV

𝜀𝜄 = 𝑆𝑁𝑇FG(𝜄<=> − 𝜄@>)

ILD_l5_v02 ILD_s5_v02 ILD_l5_v02 ILD_s5_v02

Evaluate JAR 𝜀𝜚 = 𝑆𝑁𝑇FG(𝜚<=> − 𝜚@>)

slide-10
SLIDE 10

Outline

Evaluate jet energy resolution & jet angle resolution

ILD models: large/small Ø check jet energy ＆ cosθ dependence

Study impact on physics analysis [Higgs invisible decays with hadronic recoil]

use kinematic fit (MarlinKinfit) fit variables : mass constraint : apply jet energy/angle resolution

2018/2/22

Impact of jet energy resolution on Higgs invisible decays 10

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SLIDE 11

Motivation

2018/2/22

Impact of jet energy resolution on Higgs invisible decays 11

q q

BSM

X X

invisible

Dark Matter… SUSY…

visible 𝐶𝑆 H → XX ~? ? ? %

q q Z Z ν ν ν ν

𝐶𝑆 H → ZZ∗ → 4𝜉 ~0.1% invisible visible Ø A. Ishikawa (Tohoku Univ.), ”Search for Invisible Higgs Decays at the ILC” LCWS2014@Belgrade

Previous study(A. Ishikawa) (95% CL, 250fb-1) left pol. : right pol. 0.95% : 0.69%

lIn SM, Higgs decays invisibly through H → ZZ∗ → 4𝜉 (BR(H → 𝑗𝑜𝑤.)~0.1%) lIf BR(H → 𝑗𝑜𝑤.) exceeds SM prediction , it signifies new physics beyond SM (BSM) lWe estimate upper limit of BR(H → 𝑗𝑜𝑤.) in SM lCompare result between 𝑄

=Z, 𝑄=\ = −0.8, +0.3 , (+0.8, −0.3)

Higgs→invisible

slide-12
SLIDE 12

Signal

ü２jet & missing E ü𝑁`` ≈ 𝑁b : 𝐶𝑆 Z → 𝑟𝑟 ~70% ü𝑁<=>efg ≈ 𝑁hfiij üs channel process

2018/2/22

Impact of jet energy resolution on Higgs invisible decays 12

q q X X

invisible 𝐶𝑆 H → XX ~? ? ? %

Main background

ZZ semi-leptonic WW semi-leptonic ννZ semi-leptonic

Higgs→invisible

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SLIDE 13

Analysis Setup

lSimulation

  • ILCSoft: v01-19-05
  • Samples: DBD sample + Dirac sample ( elem → qqH, H → ZZ∗ →

4ν )

  • Detector: ILD full simulation (ILD_o1_v05)
  • 𝑡
  • = 250 GeV, ∫𝑀𝑒𝑢 = 250 fb-1 , 𝑄

=Z, 𝑄=\ = −0.8, +0.3 , (+0.8, −0.3)

lFlow of analysis

1. Particle flow reconstruction (PandoraPFA)

2. Isolated lepton finder (veto)

3. Durham jet finder (forced 2 jets) 4. Kinematic fit with MarlinKinfit (OPALFitter) 5. Event selection

  • Optimized assuming signal BR(H→invisible) = 10%

6. Estimate upper limit of BR (95% CL)

  • Evaluated for BR(H→invisible) = [1,2,…10%]

2018/2/22

Impact of jet energy resolution on Higgs invisible decays 13

“Left” “Right”

Higgs→invisible

slide-14
SLIDE 14

ZH processor

pObservables (to fit) pZ mass constraint: Hard Constraint pJet mass assumption pUse parametrized jet resolution

2018/2/22

Impact of jet energy resolution on Higgs invisible decays 14

| θ |cos

0.2 0.4 0.6 0.8 1

) [%]

j

(E

90

) / Mean

j

(E

90

RMS

5 10 15

sv01-19-05.mILD_l5_o1_v02_nobg

15GeV 20GeV 30GeV 45.5GeV 60GeV 80GeV 100GeV 120GeV 150GeV 175GeV 200GeV 250GeV

| θ |cos

0.2 0.4 0.6 0.8 1

MC

θ

  • REC

θ = θ δ

0.02 0.04 0.06 0.08

sv01-19-05.mILD_l5_o1_v02_nobg

15GeV 20GeV 30GeV 45.5GeV 60GeV 80GeV 100GeV 120GeV 150GeV 175GeV 200GeV 250GeV

| θ |cos

0.2 0.4 0.6 0.8 1

MC

φ

  • REC

φ = φ δ

0.05 0.1 0.15 0.2 0.25 0.3

sv01-19-05.mILD_l5_o1_v02_nobg

15GeV 20GeV 30GeV 45.5GeV 60GeV 80GeV 100GeV 120GeV 150GeV 175GeV 200GeV 250GeV

q q X X

invisible !" H → XX ~???%

kinematic fit

slide-15
SLIDE 15

Kinematic fit: Recoil mass (signal only)

2018/2/22

Impact of jet energy resolution on Higgs invisible decays 15 Recoil Mass [GeV]

100 110 120 130 140 150 160

Events / 0.50 GeV

200 400 600

sv01-19-05.mILD_o1_v05.eL.pR

OPALFitter success : 99.85 %

before fit: mean = 130.1 sigma = 12.076 after fit: mean = 129.0 sigma = 10.496 Recoil Mass [GeV]

100 110 120 130 140 150 160

Events / 0.50 GeV

1000 2000 3000 4000

sv01-19-05.mILD_o1_v05.eL.pR

MC: mode = 125.2 sigma = 6.379

OPALFitter success : 99.85 %

sv01-19-05.mILD_o1_v05.eL.pR

Recoil Mass Relative Error

1 − 0.5 − 0.5 1

Events / 0.01

200 400 600 800 1000 1200

sv01-19-05.mILD_o1_v05.eL.pR

OPALFitter success : 99.85 %

before fit: mean = 8.4e-03 sigma = 8.8e-02 after fit: mean = -3.3e-04 sigma = 6.9e-02

sv01-19-05.mILD_o1_v05.eL.pR

↓ISR effect

improve recoil mass resolution ~20%

kinematic fit

slide-16
SLIDE 16

[GeV]

kf recoil

M

100 110 120 130 140 150 160

Events / 2.00 GeV

500 1000 1500 2000 2500

, Cut: No.1~No.9

  • 1

dt = 250 fb L

∫

) = (-0.8,+0.3),

+

,Pe

  • = 250 GeV, (Pe

s

w/ kinematic fit inv. → H BR = 10% qqH,SM ZZ WW Z ν ν

  • ther bkg

[GeV]

kf recoil

M

100 110 120 130 140 150 160

Events / 2.00 GeV

200 400 600 800

, Cut: No.1~No.9

  • 1

dt = 250 fb L

∫

) = (+0.8,-0.3),

+

,Pe

  • = 250 GeV, (Pe

s

w/ kinematic fit inv. → H BR = 10% qqH,SM ZZ WW Z ν ν

  • ther bkg

[GeV]

recoil

M

100 110 120 130 140 150 160

Events / 2.00 GeV

500 1000 1500 2000 2500

, Cut: No.1~No.9

  • 1

dt = 250 fb L

∫

) = (-0.8,+0.3),

+

,Pe

  • = 250 GeV, (Pe

s

w/o kinematic fit inv. → H BR = 10% qqH,SM ZZ WW Z ν ν

  • ther bkg

[GeV]

recoil

M

100 110 120 130 140 150 160

Events / 2.00 GeV

200 400 600 800

, Cut: No.1~No.9

  • 1

dt = 250 fb L

∫

) = (+0.8,-0.3),

+

,Pe

  • = 250 GeV, (Pe

s

w/o kinematic fit inv. → H BR = 10% qqH,SM ZZ WW Z ν ν

  • ther bkg

2018/2/22

16

Left polarization Right polarization

Impact of jet energy resolution on Higgs invisible decays

Full Result: Upper limit of BR (95% CL)

UL=0.89±0.44% UL=0.59±0.29% UL=0.63±0.32% UL=0.84±0.42% w/o kinematic fit w/ kinematic fit

Higgs→invisible

slide-17
SLIDE 17

Summary

2018/2/22

Impact of jet energy resolution on Higgs invisible decays 17

UL of BR [%] (95%CL) Left polarization Right polarization Previous study 0.95 0.69 w/o kinematic fit 0.89±0.44 0.63±0.32 w/ kinematic fit 0.84±0.42 0.59±0.29

lJet energy and angle resolution was evaluated using the latest simulation samples

  • Compared the two detector models (large/small)
  • Jet energy & angular dependence was evaluated

lThe Higgs invisible decay was studied using kinematic fit

  • The parametrized jet energy resolution was applied
  • Upper limit improved over previous study without using

kinematic fit

  • Further optimization is planned e.g. using different fitters,

scaling resolution parameters, implementing soft constraint

slide-18
SLIDE 18

backup

2018/2/22

Impact of jet energy resolution on Higgs invisible decays 18

slide-19
SLIDE 19

JAR: Comparison Large/Small

2018/2/22

Impact of jet energy resolution on Higgs invisible decays 19

[GeV]

j

E

50 100 150 200 250

)

MC

θ

  • REC

θ (

90

= RMS θ δ

0.01 0.02 0.03 0.04 0.05 0.06

|<0.7 θ sv01-19-05 |cos

mILD_l5_o1_v02_nobg mILD_s5_o1_v02_nobg

[GeV]

j

E

50 100 150 200 250

)

MC

φ

  • REC

φ (

90

= RMS φ δ

0.01 0.02 0.03 0.04 0.05 0.06

|<0.7 θ sv01-19-05 |cos

mILD_l5_o1_v02_nobg mILD_s5_o1_v02_nobg

slide-20
SLIDE 20

| θ |cos

0.2 0.4 0.6 0.8 1

θ *sin φ δ

0.02 0.04 0.06 0.08

sv01-19-05.mILD_l5_o1_v02_nobg

15GeV 20GeV 30GeV 45.5GeV 60GeV 80GeV 100GeV 120GeV 150GeV 175GeV 200GeV 250GeV

| θ |cos

0.2 0.4 0.6 0.8 1

θ *sin φ δ

0.02 0.04 0.06 0.08

sv01-19-05.mILD_s5_o1_v02_nobg

15GeV 20GeV 30GeV 45.5GeV 60GeV 80GeV 100GeV 120GeV 150GeV 175GeV 200GeV 250GeV

Angular Resolution [used as input for kinematic fit]

2018/2/22

Impact of jet energy resolution on Higgs invisible decays 20

| θ |cos

0.2 0.4 0.6 0.8 1

MC

θ

  • REC

θ = θ δ

0.02 0.04 0.06 0.08

sv01-19-05.mILD_l5_o1_v02_nobg

15GeV 20GeV 30GeV 45.5GeV 60GeV 80GeV 100GeV 120GeV 150GeV 175GeV 200GeV 250GeV

| θ |cos

0.2 0.4 0.6 0.8 1

MC

θ

  • REC

θ = θ δ

0.02 0.04 0.06 0.08

sv01-19-05.mILD_s5_o1_v02_nobg

15GeV 20GeV 30GeV 45.5GeV 60GeV 80GeV 100GeV 120GeV 150GeV 175GeV 200GeV 250GeV

𝜀𝜚 ∗ 𝑡𝑗𝑜𝜄 = 𝑆𝑁𝑇FG{ 𝜚<=> − 𝜚@> 𝑡𝑗𝑜𝜄} 𝜀𝜄 = 𝑆𝑁𝑇FG(𝜄<=> − 𝜄@>)

ILD_l5_v02 ILD_s5_v02 ILD_l5_v02 ILD_s5_v02

Evaluate JAR

slide-21
SLIDE 21

Preliminary : Soft Constraint Test

2018/2/22

Impact of jet energy resolution on Higgs invisible decays 21 [GeV]

Z

M

70 80 90 100 110 120

Events / 0.50 GeV

1 10

2

10

3

10

4

10

sv01-19-05.mILD_o1_v05.eL.pR

OPALFitter success : 99.85 %

MC: mean = 90.9 sigma = 5.338 before fit: mean = 90.7 sigma = 10.091 after fit: mean = 91.3 sigma = 1.271

OPALFitter

[GeV]

Z

M

70 80 90 100 110 120

Events / 0.50 GeV

500 1000 1500 2000 2500

sv01-19-05.mILD_o1_v05.eL.pR

NewtonFitter success : 99.93 %

MC: mean = 90.9 sigma = 5.485 before fit: mean = 90.7 sigma = 10.257 after fit: mean = 90.7 sigma = 9.964

NewtonFitter Hard constraint Soft constraint ΓZ=2.5 GeV

with SoftBWMassConstraint in MarlinKinfit

slide-22
SLIDE 22

Preliminary : Soft Constraint Test

2018/2/22

Impact of jet energy resolution on Higgs invisible decays 22

OPALFitter NewtonFitter Hard constraint Soft constraint ΓZ=2.5 GeV

with SoftBWMassConstraint in MarlinKinfit

Recoil Mass [GeV]

100 110 120 130 140 150 160

Events / 0.50 GeV

200 400 600

sv01-19-05.mILD_o1_v05.eL.pR

NewtonFitter success : 99.93 %

before fit: mean = 130.1 sigma = 12.176 after fit: mean = 130.1 sigma = 11.918

Recoil Mass [GeV]

100 110 120 130 140 150 160

Events / 0.50 GeV

200 400 600

sv01-19-05.mILD_o1_v05.eL.pR

OPALFitter success : 99.85 %

before fit: mean = 130.1 sigma = 12.076 after fit: mean = 129.0 sigma = 10.496

slide-23
SLIDE 23

Principle of kinematic fit

2018/2/22

Impact of jet energy resolution on Higgs invisible decays 23

seek minimum of under kinematic constraints method of Lagrange multipliers d.o.f.：

kinematic fit

slide-24
SLIDE 24

MarlinKinfit : OPALFitter

2018/2/22

Impact of jet energy resolution on Higgs invisible decays 24 For iterative solution : Taylor-expansion of the constraints

Convergence condition ü 𝜀𝜓x < 0.01% ∩ 𝜀𝐺

| < 10m}

∩ 𝐺

| < 10mx ~ 𝜓x

  • r

ü all 𝑔

f < 10m€ ∩ 𝜀 𝜃, 𝜊, 𝜇 < 10m€

kinematic fit

slide-25
SLIDE 25

2018/2/22

Impact of jet energy resolution on Higgs invisible decays 25

slide-26
SLIDE 26

Result：accuracy of fit

2018/2/22

Impact of jet energy resolution on Higgs invisible decays 26

2

χ

500 1000 1500 2000

Events / 2.00

1 10

2

10

3

10

4

10

sv01-19-05.mILD_o1_v05.eL.pR

OPALFitter fit success : 99.85 % mean = 14.453 sigma = 46.970

sv01-19-05.mILD_o1_v05.eL.pR

fit probability

Fit Probability

0.2 0.4 0.6 0.8 1

Events / 0.01

2

10

3

10

4

10

sv01-19-05.mILD_o1_v05.eL.pR

OPALFitter fit success : 99.85 % mean = 0.278 sigma = 0.313

sv01-19-05.mILD_o1_v05.eL.pR

←peak around０

fit with well-estimated errors →normal distributed between 0 and 1

a possibility of underestimating parameter error χ2 distribution

Mean：14.5 Ndof ：１ Mean > Ndof

kinematic fit

slide-27
SLIDE 27

Problems : Z mass distribution

2018/2/22

Impact of jet energy resolution on Higgs invisible decays 27

[GeV]

Z

M

70 80 90 100 110 120

Events / 0.50 GeV

1 10

2

10

3

10

4

10

sv01-19-05.mILD_o1_v05.eL.pR

OPALFitter success : 99.85 %

MC: mean = 90.9 sigma = 5.338 before fit: mean = 90.7 sigma = 10.091 after fit: mean = 91.3 sigma = 1.271

Error???

kinematic fit

slide-28
SLIDE 28

the Cause:

2018/2/22

Impact of jet energy resolution on Higgs invisible decays 28

kinematic fit

[GeV]

Z

M

70 80 90 100 110 120

Events / 0.50 GeV

1 10

2

10

3

10

4

10

sv01-19-05.mILD_o1_v05.eL.pR

NewtonFitter success : 99.35 %

MC: mean = 90.9 sigma = 5.486 before fit: mean = 90.4 sigma = 9.516 after fit: mean = 91.2 sigma = 0.077

[GeV]

Z

M

70 80 90 100 110 120

Events / 0.50 GeV

1 10

2

10

3

10

4

10

sv01-19-05.mILD_o1_v05.eL.pR

OPALFitter success : 99.85 %

MC: mean = 90.9 sigma = 5.338 before fit: mean = 90.7 sigma = 10.091 after fit: mean = 91.3 sigma = 1.271

OPALFitter NewtonFitter Approximate calculation of constraint in OPALFitter

slide-29
SLIDE 29

Event Selection

  • 1. isolated lepton veto
  • 2. loose restriction

[transverse di-jet momentum, di-jet invariant mass, recoil

mass from di-jet]

  • 3. number of PFOs and charged tracks: Npfo, Ntrack
  • 4. di-jet (Z) pt: PtZ
  • 5. di-jet mass: MZ
  • 6. di-jet polar angle: θZ
  • 7. recoil mass: Mrecoil
  • 8. multi-variate analysis: Boosted Decision Tree(BDT)

method

2018/2/22

Impact of jet energy resolution on Higgs invisible decays 29

slide-30
SLIDE 30

Cut table

𝑄

=Z, 𝑄=\ = −0.8, +0.3

2018/2/22

Impact of jet energy resolution on Higgs invisible decays 30

w/o kinematic fit w/ kinematic fit

Higgs→invisible

cut condition cut condition cut condition S/√S+B S/√S+B S/√S+B signal signal signal all bkg all bkg all bkg common part common part

slide-31
SLIDE 31

Cut table

𝑄

=Z, 𝑄=\ = +0.8, −0.3

2018/2/22

Impact of jet energy resolution on Higgs invisible decays 31

w/o kinematic fit w/ kinematic fit

Higgs→invisible

cut condition cut condition cut condition S/√S+B S/√S+B S/√S+B signal signal signal all bkg all bkg all bkg common part common part

slide-32
SLIDE 32

Result of Mrec dist. [Ecm = 250 GeV

, 250 fb-1,BR(H- >inv.)=10%]

2018/2/22

32

No. Cut No. Cut 1 Isolated lepton veto 5 80 < di-jet invariant mass < 100 2 Loose Cut (Ptz,Mz,Mrecoil) 6 | di-jet polar angle |< 0.9 3 #pfo >15 & #all_track > 6 & # track_in_one_jet > 1 7 100 < recoil mass < 160 4 20 GeV < di-jet Pt < 80 GeV 8 BDT cut

MVA input variables

di-jet inv. mass

  • ne jet

polar angle

di-jet polar angle

another jet polar angle

TMVA v-4.2.0

Impact of jet energy resolution on Higgs invisible decays

Right

significance: 19.7 efficiency: 65.9%

signal bkg

Left

significance: 15.5 efficiency: 63.5%

signal bkg

slide-33
SLIDE 33

How to set UL [Statistical method]

l Template

Ø Assume BR(H→invisible)=[1,2,…,10]% -> Event selection Ø Get # of events (NS+B) in window range (Mrecoil∈[120,140] GeV) Ø Generate Poisson distribution of NS+B -> Get 95% CL limit (NUL) Ø Repeat for each BR(H→invisible)=[1,2,…,10]% -> Get calibration line between NUL and UL

l Toy MC

Ø Fit template bkg -> Generate pseudo experiment by fluctuated bkg function Ø Get # of events (NS+B) in window range (Mrecoil∈[120,140] GeV) Ø Translate NS+B into UL of BR(H→invisible) using calibration line Ø Repeat 10000 times -> Obtain UL distribution 2018/2/22

Impact of jet energy resolution on Higgs invisible decays 33

NS+B NUL UL NS+B

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SLIDE 34

Plans

Evaluate jet energy resolution

  • More detailed evaluation of the end cap part : more

statistics

  • Add c-jet & b-jet information
  • Use jet clustering:
  • Add jet mass dependence

kinematic fit

  • Improve fit accuracy: check underestimation of JER
  • Implement soft constraint: ΓZ
  • Apply to other processes

Higgs→invisible

  • Use variables after fit for event selection
  • Optimize recoil mass range used for estimation
  • Set upper limit using profile likelihood ratio

2018/2/22

Impact of jet energy resolution on Higgs invisible decays 34