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Search for doubly charged Higgs bosons at √s=8TeV at CMS. Jongseok Lee, Youngil Choi, Suyong Choi 1 , Sungkyunkwan Univ., 1 Korea Univ. Oct 31, 2013. Contents. Motivation Strategy Lepton & event selection Exclusion limit Summary. Motivation.
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Search for doubly charged Higgs bosons at √s=8TeV at CMS Jongseok Lee, Youngil Choi, Suyong Choi1, Sungkyunkwan Univ., 1Korea Univ. Oct 31, 2013
Contents • Motivation • Strategy • Lepton & event selection • Exclusion limit • Summary
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 Drell-Yan pair production of doubly charged Higgs Bosons
Strategy • 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 • Electron selection pT>10 GeV, |η|<2.5, eid_mvaTrigV0>0.5, charge consistent • Muon selection pT>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
HLT efficiency 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 cross section & efficiency • MC signal samples (√s=8TeV) : full simulation data → H++H-- to l+l+l-l- → M(H±±) = 150, 200, 300, 400, 500, 600 GeV NLO calculated by Michael Spira
Mass of H++(H++H-- µ+µ+µ-µ-) preselection, M4l preliminary preliminary preliminary m(H++)=150GeV m(H++)=200GeV m(H++)=300GeV preliminary preliminary preliminary m(H++)=400GeV m(H++)=500GeV m(H++)=600GeV 8
Mass of H++ (H++H-- e+e+e-e-) preselection, M4l preliminary preliminary preliminary m(H++)=150GeV m(H++)=200GeV m(H++)=300GeV preliminary preliminary preliminary m(H++)=400GeV m(H++)=500GeV m(H++)=600GeV 9
Mass of H++(H++H-- e+µ+e-µ-) preselection, M4l preliminary preliminary preliminary m(H++)=150GeV m(H++)=200GeV m(H++)=300GeV preliminary preliminary preliminary m(H++)=400GeV m(H++)=500GeV m(H++)=600GeV 10
Expected yieldsat 8TeV & 19.5 fb-1 preselection, M4l There is no signal excess in 19.5 fb-1.
Exclusion limit preselection, M4l preliminary preliminary 4µ Expected Limit : 526 GeV Observed Limit : 528 GeV 4e Expected Limit : 504 GeV Observed Limit : 505 GeV preliminary eµeµ Expected Limit : 510 GeV Observed Limit : 512 GeV
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
backup • 8TeV samples • HLT & skim • Lepton cut variables • Cut variables for event selection • Background estimation • Systematic uncertainties • Exclusion limit at 7TeV & 4.98fb-1
Signal samples • MC signal samples (√s=8TeV) : full simulation data → H++H-- to l+l+l-l- → M(H±±) = 150, 200, 300, 400, 500GeV calculated by Michael Spira
Background samples • MC background samples : full simulation data → ZZJetsTo4L(Dominant background), WZJetsTo3LNu, TTTo2L2Nu2B, DYJetsToLL,
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
HLT efficiency HLT_Mu17_Mu8 HLT_Mu17_TkMu8 HLT_Ele17_CaloIdT_CaloIsoVL_TrkIdVL_TrkIsoVL_Ele8_CaloIdT_CaloIsoVL_TrkIdVL_TrkIsoVL HLT_Ele15_Ele8_Ele5_CaloIdL_TrkIdVL HLT_Mu8_Ele17_CaloIdT_CaloIsoVL_TrkIdVL_TrkIsoVL HLT_Mu17_Ele8_CaloIdT_CaloIsoVL_TrkIdVL_TrkIsoVL
Skim efficiency Skim conditions : 1st pt>10 2nd pt>15 # of good vertices >= 1
Skim efficiency Skim conditions : 1st pt>10 2nd pt>15 # of good vertices >= 1
Muon cut variables nm>=2, pt>10, |η|<2.4, tight muon, relIso<0.12, 60<Mll<120
Mµµ nm>=2, pt>10, |η|<2.4, tight muon, relIso<0.12 lumi : 19.47 fb-1 cross section of DY for 60<Mll<120 : 3351.97 fb
Electron cut variables ne>=2, pt>10, |η|<2.5, charge consistent, eid_mvaTrigV0>0.5, relIso<0.2, 60<Mll<120
Mee ne>=2, pt>10, |η|<2.5, charge consistent, eid_mvaTrigV0>0.5, relIso<0.2 lumi : 19.47 fb-1 cross section of DY for 60<Mll<120 : 3351.97 fb
Cut variables for event selection(µµµµ) nlep+>=2, nlep->=2, m(H++)>10GeV, m(H--)>10GeV, relIso<0.12 m(H++)=200GeV
Cut variables for event selection(eeee) nlep+>=2, nlep->=2, m(H++)>10GeV, m(H--)>10GeV, relIso<0.2 m(H++)=200GeV
Cut variables for event selection(eµeµ) 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 preliminary preliminary preliminary m(H++)=150GeV m(H++)=200GeV m(H++)=300GeV preliminary preliminary m(H++)=400GeV m(H++)=500GeV 31
Me+e+e-e-at 19.5 fb-1 preselection - nlep+>=2, nlep->=2, mp>10, mn>10, relIso<0.2 preliminary preliminary preliminary m(H++)=150GeV m(H++)=200GeV m(H++)=300GeV preliminary preliminary m(H++)=400GeV m(H++)=500GeV 32
Me+µ+e-µ-at 19.5 fb-1 preselection - nlep+>=2, nlep->=2, mp>10, mn>10, relIso<0.2 preliminary preliminary preliminary m(H++)=150GeV m(H++)=200GeV m(H++)=300GeV preliminary preliminary m(H++)=400GeV m(H++)=500GeV 33
# of expected eventsat 8TeV & 19.5 fb-1 preselection : nlep+>=2, nlep->=2, m(H±±)>10, relIso<0.12
# of expected eventsat 8TeV & 19.5 fb-1 preselection : nlep+>=2, nlep->=2, m(H±±)>10, relIso<0.2
# of expected eventsat 8TeV & 19.5 fb-1 preselection : nlep+>=2, nlep->=2, m(H±±)>10, relIso<0.2
Signal region and side band m(H--) 600GeV signal region side band 10GeV 10GeV 600GeV m(H++)
Mass of H++ VS H--(µµµµ) nlep+>=2, nlep->=2, m(H++)>10GeV, m(H--)>10GeV, relIso<0.12, m4 MC signal region MC signal region MC signal region Data signal region Data signal region Data signal region
# of events nlep+>=2, nlep->=2, relIso<0.12, m4, signal region (5σ) ± α error ± relative error ± statistical error
Mass of H++ VS H--(eeee) nlep+>=2, nlep->=2, m(H++)>10GeV, m(H--)>10GeV, relIso<0.2, m4 MC signal region MC signal region MC signal region Data signal region Data signal region Data signal region
# of events nlep+>=2, nlep->=2, relIso<0.2, m4, signal region (5σ) ± α error ± relative error ± statistical error
Mass of H++ VS H--(eµeµ) nlep+>=2, nlep->=2, m(H++)>10GeV, m(H--)>10GeV, relIso<0.2, m4 MC signal region MC signal region MC signal region Data signal region Data signal region Data signal region
# of events nlep+>=2, nlep->=2, relIso<0.2, m4, signal region (5σ) ± α error ± relative error ± statistical error
Systematic uncertainties • Luminosity : 4.4% • Pile-up : 5%
Exclusion limit at 7TeV & 4.98fb-1 preselection, M4l 4µ Expected Limit : 385 GeV Observed Limit : 399 GeV 4e Expected Limit : 375 GeV Observed Limit : 399 GeV eµeµ Expected Limit : 385 GeV Observed Limit : 399 GeV