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