Search for doubly charged Higgs bosons

at √s=8TeV at CMS

Jongseok Lee, Youngil Choi, Suyong Choi1, Sungkyunkwan Univ., 1Korea Univ.

Oct 31, 2013

1

Contents• Motivation

• Strategy

• Lepton & event selection

• Exclusion limit

• Summary

2

Motivation• The existence of non-zero neutrino masses is a firmly established signal

of particle physics beyond the standard model.

• In minimal seesaw model of type II with expanded Higgs sector, one can have Higgs triplets.

Doubly charged Higgs

• Pair production : through Drell-Yan process

3Drell-Yan pair production of doubly charged Higgs Bosons

Strategy

4

• H++H-- µ+µ+µ-µ- ,assuming Br(H++ µ+µ+)=100%, e+e+e-e-, assuming Br(H++ e+e+)=100%, µ+e+µ-e-, assuming Br(H++ µ+e+)=100%

• Event selection

1) Guarantee 4 lepton : l+l+l-l- N(l+)>=2, N(l-) >=2, 2) Dominant background is ZZ to 4l Using quad-lepton mass to distinguish with ZZ candidates

Lepton & event selection

5

• Electron selection pT>10 GeV, |η|<2.5, eid_mvaTrigV0>0.5, charge consistent

• Muon selectionpT>10 GeV, |η|<2.4, tight muon

• Preselection : nlep+>=2, nlep->=2, Mll>10 GeV, relIso

• Event selection - mass dependent cut- quad-lepton mass : M4l > cut value

6

HLT paths :

m+m+m-m- : HLT_Mu17_Mu8, HLT_Mu17_TkMu8

e+e+e-e- : HLT_Ele17_CaloIdT_CaloIsoVL_TrkIdVL_TrkIsoVL_Ele8_CaloIdT_CaloIsoVL_TrkIdVL_TrkIsoVL HLT_Ele15_Ele8_Ele5_CaloIdL_TrkIdVL

e+m+e-m- : HLT_Mu8_Ele17_CaloIdT_CaloIsoVL_TrkIdVL_TrkIsoVL HLT_Mu17_Ele8_CaloIdT_CaloIsoVL_TrkIdVL_TrkIsoVL

Signal H++H-- to µ+µ+µ-

µ-

H++H-- to e+e+e-

e-

H++H-- to e+µ+e-

µ-

150 GeV 98.9% 98.1% 98.7%

300 GeV 99.9% 99.0% 99.6%

500 GeV 100% 99.2% 99.7%

Background

ZZJetsTo4L DYJetsToLL WJetsToLNu TTTo2L2Nu2B

54.5% 28.7% 0.224% 42.7%

HLT efficiency

Signal cross section & efficiency

7

NLO calculated by Michael Spira

• MC signal samples (√s=8TeV) : full simulation data → H++H-- to l+l+l-l-

→ M(H±±) = 150, 200, 300, 400, 500, 600 GeV

Mass of H++

(H++H-- µ+µ+µ-µ-)preselection, M4l

8

m(H+

+)=150GeVm(H+

+)=200GeVm(H+

+)=300GeV

m(H+

+)=600GeVm(H+

+)=400GeVm(H+

+)=500GeV

preliminary

preliminary

preliminary

preliminary

preliminary

preliminary

Mass of H++

(H++H-- e+e+e-e-)preselection, M4l

9

preliminary

preliminary

preliminary

preliminary

preliminary

preliminary

m(H+

+)=150GeVm(H+

+)=200GeVm(H+

+)=300GeV

m(H+

+)=600GeVm(H+

+)=400GeVm(H+

+)=500GeV

Mass of H++

(H++H-- e+µ+e-µ-)preselection, M4l

10

preliminary

preliminary

preliminary

preliminary

preliminary

preliminary

m(H+

+)=150GeVm(H+

+)=200GeVm(H+

+)=300GeV

m(H+

+)=600GeVm(H+

+)=400GeVm(H+

+)=500GeV

11

Channel M(H++)GeV/c2

Signal(MC)

Background(MC)

Data

µ+µ+µ-µ-

150 955 ± 7 13.7 ± 0.1 12

300 56.4 ± 0.6 0.698 ± 0.024 2

500 4.46 ± 0.06 0.089 ± 0.010 0

e+e+e-e-

150 769 ± 7 9.16 ± 0.10 8

300 44.2 ± 0.6 0.489 ± 0.034 0

500 3.27 ± 0.06 0.054 ± 0.008 0

e+µ+e-µ-

150 893 ± 8 24.2 ± 0.2 20

300 52.2 ± 0.7 1.14 ± 0.04 1

500 3.48 ± 0.07 0.071 ± 0.008 0

Expected yieldsat 8TeV & 19.5 fb-1

preselection, M4l

There is no signal excess in 19.5 fb-1.

Exclusion limit

12

preselection, M4l

4µExpected Limit : 526 GeVObserved Limit : 528 GeV

4eExpected Limit : 504 GeVObserved Limit : 505 GeV

eµeµExpected Limit : 510 GeVObserved Limit : 512 GeV

preliminary

preliminary

preliminary

Conclusion

• No signal excess

• Lower mass limits of 95% Confidence Level for H++ mass at 8TeV & 19.5fb-1

- μμμμ channel : 528 GeV- eeee channel : 505 GeV- eμeμ channel : 512 GeV

13

backup

14

• 8TeV samples

• HLT & skim

• Lepton cut variables

• Cut variables for event selection

• Background estimation

• Systematic uncertainties

• Exclusion limit at 7TeV & 4.98fb-1

• MC signal samples (√s=8TeV) : full simulation data → H++H-- to l+l+l-l-

→ M(H±±) = 150, 200, 300, 400, 500GeV

Signal samples

15

calculated by Michael Spira

Background samples

• MC background samples : full simulation data → ZZJetsTo4L(Dominant background), WZJetsTo3LNu, TTTo2L2Nu2B, DYJetsToLL,

16

MC samples/HPlusPlusHMinusMinusHTo4L_M-150_8TeV-pythia6/jslee-v5-Summer12_m150-015c8de628e382b4e72a8b773fb02e51/USER/HPlusPlusHMinusMinusHTo4L_M-200_8TeV-pythia6/jslee-v5-Summer12_m200-015c8de628e382b4e72a8b773fb02e51/USER/HPlusPlusHMinusMinusHTo4L_M-300_8TeV-pythia6/jslee-v5-Summer12_m300-015c8de628e382b4e72a8b773fb02e51/USER/HPlusPlusHMinusMinusHTo4L_M-400_8TeV-pythia6/jslee-v5-Summer12_m400-015c8de628e382b4e72a8b773fb02e51/USER/HPlusPlusHMinusMinusHTo4L_M-500_8TeV-pythia6/jslee-v5-Summer12_m500-015c8de628e382b4e72a8b773fb02e51/USER/HPlusPlusHMinusMinusHTo4L_M-600_8TeV-pythia6/jslee-v5-Summer12_m600-015c8de628e382b4e72a8b773fb02e51/USER

/DYJetsToLL_M-50_TuneZ2Star_8TeV-madgraph-tarball/jslee-v5-Summer12_DYJetsToLL_M-50-015c8de628e382b4e72a8b773fb02e51/USER/DYJetsToLL_M-10To50filter_8TeV-madgraph/jslee-v5-Summer12_DYJetsToLL_M-10To50-015c8de628e382b4e72a8b773fb02e51/USER/ZZJetsTo4L_TuneZ2star_8TeV-madgraph-tauola/jslee-v5-Summer12_ZZJetsTo4L-015c8de628e382b4e72a8b773fb02e51/USER/ZZJetsTo2L2Q_TuneZ2star_8TeV-madgraph-tauola/jslee-v5-Summer12_ZZJetsTo2L2Q-015c8de628e382b4e72a8b773fb02e51/USER/ZZJetsTo2L2Nu_TuneZ2star_8TeV-madgraph-tauola/jslee-v5-Summer12_ZZJetsTo2L2Nu-015c8de628e382b4e72a8b773fb02e51/USER/WZJetsTo3LNu_TuneZ2_8TeV-madgraph-tauola/jslee-v5-Summer12_WZJetsTo3LNu-015c8de628e382b4e72a8b773fb02e51/USER/WWJetsTo2L2Nu_TuneZ2star_8TeV-madgraph-tauola/jslee-v5-Summer12_WWJetsTo2L2Nu-015c8de628e382b4e72a8b773fb02e51/USER/TTTo2L2Nu2B_8TeV-powheg-pythia6/jslee-v5-Summer12_TTTo2L2Nu2B-015c8de628e382b4e72a8b773fb02e51/USER/Tbar_tW-channel-DR_TuneZ2star_8TeV-powheg-tauola/jslee-v5-Summer12_Tbar_tW-channel-015c8de628e382b4e72a8b773fb02e51/USER/Tbar_t-channel_TuneZ2star_8TeV-powheg-tauola/jslee-v5-Summer12_Tbar_t-channel-015c8de628e382b4e72a8b773fb02e51/USER/Tbar_s-channel_TuneZ2star_8TeV-powheg-tauola/jslee-v5-Summer12_Tbar_s-channel-015c8de628e382b4e72a8b773fb02e51/USER/T_tW-channel-DR_TuneZ2star_8TeV-powheg-tauola/jslee-v5-Summer12_T_tW-channel-015c8de628e382b4e72a8b773fb02e51/USER/T_t-channel_TuneZ2star_8TeV-powheg-tauola/jslee-v5-Summer12_T_t-channel-015c8de628e382b4e72a8b773fb02e51/USER/T_s-channel_TuneZ2star_8TeV-powheg-tauola/jslee-v5-Summer12_T_s-channel-015c8de628e382b4e72a8b773fb02e51/USER/TTWJets_8TeV-madgraph/jslee-v5-Summer12_TTWJets-211b7640726e8e08bdbb25f6c44b3e28/USER/TTZJets_8TeV-madgraph_v2/jslee-v5-Summer12_TTZJets-211b7640726e8e08bdbb25f6c44b3e28/USER/ZZZNoGstarJets_8TeV-madgraph/jslee-v5-Summer12_ZZZNoGstarJets-211b7640726e8e08bdbb25f6c44b3e28/USER/WZZNoGstarJets_8TeV-madgraph/jslee-v5-Summer12_WZZNoGstarJets-211b7640726e8e08bdbb25f6c44b3e28/USER/WWZNoGstarJets_8TeV-madgraph/jslee-v5-Summer12_WWZNoGstarJets-211b7640726e8e08bdbb25f6c44b3e28/USER /WWWJets_8TeV-madgraph/jslee-v5-Summer12_WWWJets-211b7640726e8e08bdbb25f6c44b3e28/USER/WJetsToLNu_TuneZ2Star_8TeV-madgraph-tarball/jslee-v5-Summer12_WJetsToLNu-211b7640726e8e08bdbb25f6c44b3e28/USER

17

18

2012 DoubleElectron data Integrated Lumi.

DoubleElectron_Run2012A_13Jul2012_v1 0.808 fb-1

DoubleElectron_Run2012A_recover_06Aug2012_v1 0.082 fb-1

DoubleElectron_Run2012B_13Jul2012_v1 4.429 fb-1

DoubleElectron_Run2012C_24Aug2012_v1 0.495 fb-1

DoubleElectron_Run2012C_PromptReco_v2 6.399 fb-1

DoubleElectron_Run2012D_22Jan2013_v1 7.318 fb-1

Total 19.5 fb-1

2012 DoubleMu data Integrated Lumi.

DoubleMu_Run2012A_13Jul2012_v1 0.808 fb-1

DoubleMu_Run2012A_recover_06Aug2012_v1 0.082 fb-1

DoubleMu_Run2012B_13Jul2012_v4 4.429 fb-1

DoubleMu_Run2012C_24Aug2012_v1 0.495 fb-1

DoubleMu_Run2012C_PromptReco_v2 6.397 fb-1

DoubleMu_Run2012D_PromptReco_v1 7.256 fb-1

Total 19.5 fb-1

2012 MuEG data Integrated Lumi.

MuEG_Run2012A_13Jul2012_v1 0.808 fb-1

MuEG_Run2012A_recover_06Aug2012_v1 0.082 fb-1

MuEG_Run2012B_13Jul2012_v1 4.429 fb-1

MuEG_Run2012C_24Aug2012_v1 0.495 fb-1

MuEG_Run2012C_PromptReco_v2 6.402 fb-1

MuEG_Run2012D_22Jan2013_v1 7.309 fb-1

Total 19.5 fb-1

HLT efficiency

19

HLT_Mu17_Mu8HLT_Mu17_TkMu8HLT_Ele17_CaloIdT_CaloIsoVL_TrkIdVL_TrkIsoVL_Ele8_CaloIdT_CaloIsoVL_TrkIdVL_TrkIsoVLHLT_Ele15_Ele8_Ele5_CaloIdL_TrkIdVLHLT_Mu8_Ele17_CaloIdT_CaloIsoVL_TrkIdVL_TrkIsoVLHLT_Mu17_Ele8_CaloIdT_CaloIsoVL_TrkIdVL_TrkIsoVL

HLT efficiency

20

21

Signal H++H-- to µ+µ+µ-

µ-

H++H-- to e+e+e-

e-

H++H-- to e+µ+e-

µ-

150 GeV 99.8% 99.7% 99.8%

300 GeV 99.9% 99.9% 99.9%

500 GeV 100% 100% 99.9%

Background

ZZJetsTo4L DYJetsToLL WJetsToLNu TTTo2L2Nu2B

94.8% 94.2% 50.3% 94.2%

Skim efficiency

Skim conditions :

1st pt>102nd pt>15# of good vertices >= 1

Skim efficiency

22

Skim conditions :

1st pt>102nd pt>15# of good vertices >= 1

Skim efficiency

23

Muon cut variables

24

nm>=2, pt>10, |η|<2.4, tight muon, relIso<0.12, 60<Mll<120

Mµµ

25

nm>=2, pt>10, |η|<2.4, tight muon, relIso<0.12

lumi : 19.47 fb-1

cross section of DYfor 60<Mll<120 : 3351.97 fb

Electron cut variables

26

ne>=2, pt>10, |η|<2.5, charge consistent, eid_mvaTrigV0>0.5, relIso<0.2, 60<Mll<120

Mee

27

ne>=2, pt>10, |η|<2.5, charge consistent, eid_mvaTrigV0>0.5, relIso<0.2

lumi : 19.47 fb-1

cross section of DYfor 60<Mll<120 : 3351.97 fb

Cut variables for event selection

(µµµµ)

28

nlep+>=2, nlep->=2, m(H++)>10GeV, m(H--)>10GeV, relIso<0.12

m(H++)=200GeV

Cut variables for event selection

(eeee)

29

nlep+>=2, nlep->=2, m(H++)>10GeV, m(H--)>10GeV, relIso<0.2

m(H++)=200GeV

Cut variables for event selection

(eµeµ)

30

nlep+>=2, nlep->=2, m(H++)>10GeV, m(H--)>10GeV, relIso<0.2

m(H++)=200GeV

Mµ+µ+µ-µ- at 19.5 fb-1

preselection - nlep+>=2, nlep->=2, mp>10, mn>10, relIso<0.12

31

m(H+

+)=150GeVm(H+

+)=200GeVm(H+

+)=300GeV

m(H+

+)=500GeVm(H+

+)=400GeV

preliminary

preliminary

preliminary

preliminary

preliminary

Me+e+e-e- at 19.5 fb-1

preselection - nlep+>=2, nlep->=2, mp>10, mn>10, relIso<0.2

32

m(H+

+)=150GeVm(H+

+)=200GeVm(H+

+)=300GeV

m(H+

+)=500GeVm(H+

+)=400GeV

preliminary

preliminary

preliminary

preliminary

preliminary

Me+µ+e-µ- at 19.5 fb-1

preselection - nlep+>=2, nlep->=2, mp>10, mn>10, relIso<0.2

33

m(H+

+)=150GeVm(H+

+)=200GeVm(H+

+)=300GeV

m(H+

+)=500GeVm(H+

+)=400GeV

preliminary

preliminary

preliminary

preliminary

preliminary

34

H++H-- to µ+µ+µ-µ-

Cuts M(H++) H++H-- to µµµµ Background(MC)

Data

Preslection

150GeV 958±7

56.7±0.2

54

300GeV 62.4±0.6

56.7±0.2

54

500GeV 4.67±0.06

56.7±0.2

54

M4l

150GeV 955±7

13.7±0.1

12

300GeV 56.4±0.6

0.698±0.024

2

500GeV 4.46±0.06

0.089±0.010

0

# of expected eventsat 8TeV & 19.5 fb-1

preselection : nlep+>=2, nlep->=2, m(H±±)>10, relIso<0.12

35

H++H-- to e+e+e-e-

Cuts M(H++) H++H-- to eeee Background(MC)

Data

Preslection

150GeV 772±7

38.6±0.2

35

300GeV 48.5±0.6

38.6±0.2

35

500GeV 3.37±0.06

38.6±0.2

35

M4l

150GeV 769±7

9.16±0.10

8

300GeV 44.2±0.6

0.489±0.034

0

500GeV 3.270.06

0.054±0.008

0

# of expected eventsat 8TeV & 19.5 fb-1

preselection : nlep+>=2, nlep->=2, m(H±±)>10, relIso<0.2

36

H++H-- to e+µ+e-µ-

Cuts M(H++) H++H-- to eµeµ Background(MC)

Data

Preslection

150GeV 898±8

105±2

103

300GeV 56.8±0.7

105±2

103

500GeV 4.02±0.07

105±2

103

M4l

150GeV 893±8

24.2±0.2

20

300GeV 52.2±0.7

1.14±0.04

1

500GeV 3.48±0.07

0.071±0.008

0

# of expected eventsat 8TeV & 19.5 fb-1

preselection : nlep+>=2, nlep->=2, m(H±±)>10, relIso<0.2

Sideband method

37

events. of # reasonable afor selection event without events of# theis N and N

yuncertaint lstatistica N assumed isit then y,uncertaint lstatistica N If

sidebands. in the events data of # total theis N

data, from estimatedregion signal in the events background of # theis N where

,1 N

1 oferror relative a and

,1 N N

yuncertaint lstatistica N assumed isit then y,uncertaint lstatistica N if

, N assumed isit then 0, N if

MC. by the prediced as regions sideband and signal in the events theare N and N where

,N

N

region. signal in theon contributi background theestimate toused is method sidebandA

DataSBSB

BGSRBGSR

DataSB

BGSR

DataSB

DataSBBGSR

SRSR

SRSB

SBSR

SB

SR

Signal region and side band

38

m(H++)

m(H--)

side band

signal region

10GeV 600GeV

600GeV

10GeV

Mass of H++ VS H--

(µµµµ)

39

nlep+>=2, nlep->=2, m(H++)>10GeV, m(H--)>10GeV, relIso<0.12, m4

MCsignal region

Datasignal region

MCsignal region

Datasignal region

Datasignal region

MCsignal region

# of events

40

mmmmMass of H++

(GeV)In signal region

(MC background)In signal region

by sideband method

In signal region(Data)

150 0.604±0.021

0.597±0.021±0.081

0

200 0.289±0.016

0.269±0.014±0.037

1.0±1.0

300 0.110±0.011

0.103±0.010±0.014

0

400 0.032±0.008

0.031±0.008±0.004

0

500 0.007±0.002

0.007±0.002±0.001

0

600 0.005±0.001

0.005±0.002±0.001

0

nlep+>=2, nlep->=2, relIso<0.12, m4, signal region (5σ)

± statistical error ± α error ± relative error

Mass of H++ VS H--

(eeee)

41

nlep+>=2, nlep->=2, m(H++)>10GeV, m(H--)>10GeV, relIso<0.2, m4

MCsignal region

Datasignal region

MCsignal region

Datasignal region

Datasignal region

MCsignal region

# of events

42

eeeeMass of H++

(GeV)In signal region

(MC background)In signal region

by sideband method

In signal region(Data)

150 0.432±0.018

0.396±0.017±0.068

0

200 0.217±0.023

0.200±0.021±0.044

1.0±1.0

300 0.060±0.006

0.057±0.006±0.009

0

400 0.029±0.011

0.026±0.010±0.004

0

500 0.003±0.002

0.003±0.001±0.001

0

600 0.001±0.001

0.001±0.001±0.001

0

nlep+>=2, nlep->=2, relIso<0.2, m4, signal region (5σ)

± statistical error ± α error ± relative error

Mass of H++ VS H--

(eµeµ)

43

nlep+>=2, nlep->=2, m(H++)>10GeV, m(H--)>10GeV, relIso<0.2, m4

MCsignal region

Datasignal region

MCsignal region

Datasignal region

Datasignal region

MCsignal region

# of events

44

ememMass of H++

(GeV)In signal region

(MC background)In signal region

by sideband method

In signal region(Data)

150 1.108±0.028

1.089±0.036±0.109

2.0±1.4

200 0.561±0.021

0.553±0.024±0.055

2.0±1.4

300 0.175±0.012

0.174±0.013±0.017

0

400 0.031±0.007

0.031±0.007±0.003

0

500 0.002±0.001

0.002±0.001±0.001

0

600 0.003±0.001

0.003±0.001±0.001

0

nlep+>=2, nlep->=2, relIso<0.2, m4, signal region (5σ)

± statistical error ± α error ± relative error

Systematic uncertainties

• Luminosity : 4.4%

• Pile-up : 5%

45

Exclusion limit at 7TeV & 4.98fb-1

46

4µExpected Limit : 385 GeVObserved Limit : 399 GeV

preselection, M4l

4eExpected Limit : 375 GeVObserved Limit : 399 GeV

eµeµExpected Limit : 385 GeVObserved Limit : 399 GeV