Higgs Boson Searches in ATLAS

Transcription

1 Higgs Boson Searches in ATLAS Wolfgang F. Mader Institut für Kern- und Teilchenphysik TU Dresden Fourth fermion generation and single-top production March 202 Leinsweiler, Pfalz, Germany Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS / 28

2 Outline The ATLAS Detector and Performance 2 Standard Model Higgs Searches The Standard Model Higgs Boson Low-Mass Higgs Searches High-Mass Higgs Searches Combination of Standard Model Results 3 Higgs Searches Beyond the Standard Model Fermiophobic Higgs MSSM Neutral Higgs Charged Higgs Doubly-Charged Higgs Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 2/ 28

3 The ATLAS Detector Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 3/ 28

4 Performance of ATLAS and the LHC LHC Integrated Luminosity ATLAS Data Taking Efficiency ] Total Integrated Luminosity [fb 7 ATLAS Online Luminosity s = 7 TeV LHC Delivered ATLAS Recorded Total Delivered: 5.6 fb Total Recorded: 5.25 fb Recording Efficiency [percent] ATLAS Online Total Efficiency: 93.5% s = 7 TeV 0 28/02 30/04 30/06 30/08 3/ Day in /02 30/04 30/06 30/08 3/ Day in 20 Excellent LHC Performance in 20 Peak Luminosity cm 2 s fb Passed in June 20 Excellent Performance of ATLAS Small Fraction of non-working Detector Channels ( 3.5%) Data-Taking Efficiency 93.5% 90 96% of Data Used for Analyses (Good Quality Depends on Analysis) Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 4/ 28

5 Performance of ATLAS and the LHC ] Recorded Luminosity [pb 4 ATLAS Online 20, s=7 TeV Ldt=5.2 fb β * =.0 m, <µ> =.6 β * =.5 m, <µ> = Mean Number of Interactions per Crossing Z µµ Candidate with 20 Vertices Up to 20 Interactions Comparable to Design Luminosity Challenging for Trigger Computing Resources Isolation Criteria Vertexing E miss T and Energy Sclaes... Continuing Performance Studies to Understand Impact of Pile-Up Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 4/ 28

6 Outline The ATLAS Detector and Performance 2 Standard Model Higgs Searches The Standard Model Higgs Boson Low-Mass Higgs Searches High-Mass Higgs Searches Combination of Standard Model Results 3 Higgs Searches Beyond the Standard Model Fermiophobic Higgs MSSM Neutral Higgs Charged Higgs Doubly-Charged Higgs Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 5/ 28

7 The Standard Model Higgs LHC Production Cross Section (arxiv:.0593) σ(pp H+X) [pb] pp H (NNLO+NNLL QCD + NLO EW) qqh (NNLO QCD + NLO EW) pp pp WH (NNLO QCD + NLO EW) pp ZH (NNLO QCD +NLO EW) s= 7 TeV LHC HIGGS XS WG 20 pp tth (NLO QCD) M H [GeV] Dominant Production Mode: gg H Sub-Dominant Modes: Vector-Boson Fusion: q q Hq q Higgsstrahlung q q VH (V {W, Z }) Small Contribution from Associated Production: gg t th Total Cross Section 20 Higher TEVATRON Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 6/ 28

8 The Standard Model Higgs LHC Branching Fractions (arxiv: ) σ BR (pb) s = 7TeV ± WW l νqq LHC HIGGS XS WG WW l νl ν + - ZZ l l qq ZZ l l νν - τ + τ ZZ l l l l -3 l = e, µ ± γγ WH l νbb ν = ν e,ν µ,ν - τ + ZH l l bb q = udscb Higgs boson mass (GeV) m H 35 GeV Dominant: H b b Sub-Dominant: H WW ( ), H ττ H γγ very Sensitive despite low Branching Fraction m H 35 GeV Dominant: H WW ( ) Cleanest Mode: H ZZ ( ) (Golden Channel) Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 6/ 28

9 The Standard Model Higgs LHC Branching Fractions (arxiv: ) σ BR (pb) s = 7TeV ± WW l νqq LHC HIGGS XS WG WW l νl ν + - ZZ l l qq ZZ l l νν - τ + τ ZZ l l l l -3 l = e, µ ± γγ WH l νbb ν = ν e,ν µ,ν - τ + ZH l l bb q = udscb Higgs boson mass (GeV) m H 35 GeV Dominant: H b b Sub-Dominant: H WW ( ), H ττ H γγ very Sensitive despite low Branching Fraction m H 35 GeV Dominant: H WW ( ) Cleanest Mode: H ZZ ( ) (Golden Channel) Mass-Dependent Higgs Searches in < m H < 600 GeV Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 6/ 28

10 The Standard Model Higgs LHC Measurement of Background Processes Excellent Agreement with Standard Model Predictions Important for Background Estimates in Higgs Boson Searches Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 7/ 28

11 Status of Higgs Boson Searches Results Summer Conferences 20 Higgs Boson Mass 95% CL 4.4 < m H < 4 GeV m H > 476 GeV Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 8/ 28

12 Status of Higgs Boson Searches Updates for 20 Analyses Unchanged: H γγ, H ZZ ( ) 4l Updated: H WW ( ) lνlν (lνq q ), H ZZ ( ) llνν(llq q) New: H ττ, H b b Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 8/ 28

13 Systematic Uncertainties (Experiment) Treatment of Background Estimated in Data from Signal-Free, Background-Enriched Control Regions Otherwise: Estimate Taken from Simulation W/Z+Jets: ALPGEN (Heavy Flavor also from SHERPA or POWHEG) t t, Single Top: MC@NLO/AcerMC Di-Boson: MC@NLO, SHERPA, PYTHIA Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 9/ 28

14 Systematic Uncertainties (Theory) Signal Processes MC Generator: POWHEG+PYTHIA for ggh and VBF (qq Hqq) PYTHIA for WH/ZH and t th Theoretical Calculations: ggh : NNLO QCD + NNLL Soft-Gluon Resummation; NLO EW VBF : NLO QCD + Approximate NNLO Corrections; NLO EW ZH : NNLO QCD + NLO EW Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS / 28

15 Statistical Analysis Profile-Likelihood Method (Eur.Phys.J.C7:554,20) L(µ, Θ) = Π j=bin Poisson(N j µs j (Θ) + b j (Θ))Π Θ Gaussian(Θ 0, ) µ : Signal-Strength Parameter (Parameter of Interest σ/σ SM ) Θ : Vector of Nuissance Parameters N j : Observed Number of Events in Bin j s j : Predicted Number of Signal Events in Bin j b j : Predicted Number of Background Events in Bin j! L(µ,ˆΘ µ) q µ = 2ln L(ˆµ, ˆΘ) ˆµ : Best Estimator for Signal-Strength Parameter ˆΘ : Best Estimator for Nuissance Parameters ˆΘ µ : Best Estimator for Nuissance Parameters Given Signal-Strength Hypothesis µ Exclusion Limits on µ Are 95% CL Using CL S Method (J. Phys. G 28 (2002) ) Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS / 28

16 Low-Mass Higgs Boson Searches Good Mass Resolution H γγ H ZZ ( ) 4l Limted Mass Resolution H WW ( ) lνlν H ττ W /ZH, H b b Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 2/ 28

17 Low-Mass Higgs Searches H γγ (arxiv:202.44) st γ: 2 nd γ: E T = 64.2 GeV η = 0.34 E T = 6.4 GeV η = 0.6 m γγ: = 26.6 GeV Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 3/ 28

18 Low-Mass Higgs Searches H γγ (arxiv:202.44) Signal Model Christal Ball + Gaussian Tail (σ CB = GeV) Mass Scale Uncertainty 0.7 GeV (m H = 20 GeV) Mass Reconstruction Robust against Pile-Up Background Model Simultaneous Fit to all 9 Categories Exponential Function (Free Slope/Normalization) Modeling Uncertainty ( Events) Events / GeV Data - Bkg ATLAS Selected diphoton sample Data 20 Background model SM Higgs boson m H = 20 GeV (MC) s = 7 TeV, Ldt = 4.9 fb m γ γ [GeV] Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 3/ 28

19 Low-Mass Higgs Searches H γγ (arxiv:202.44) Signal Model Christal Ball + Gaussian Tail (σ CB = GeV) Mass Scale Uncertainty 0.7 GeV (m H = 20 GeV) Mass Reconstruction Robust against Pile-Up Background Model Simultaneous Fit to all 9 Categories Exponential Function (Free Slope/Normalization) Modeling Uncertainty ( Events) Main Backgrounds (Inverted γ ID and Isolation) irreducible γγ (30 pb) reducible γj (20 nb) reducible jj (500 µb) Events / GeV Data - Bkg ATLAS Selected diphoton sample Data 20 Background model SM Higgs boson m H = 20 GeV (MC) s = 7 TeV, Ldt = 4.9 fb m γ γ [GeV] Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 3/ 28

20 Low-Mass Higgs Searches H γγ (arxiv:202.44) 95% CL limit on σ/σ SM Observed CL s limit Expected CL s limit ± σ H γγ ATLAS ± 2σ Data 20, s = 7 TeV Ldt = 4.9 fb [GeV] m H Observed Exclusion: 3 5 GeV and GeV Largest m H = 26.5 GeV Local Significance: 2.8σ (Global:.5σ for < m H < 50 GeV) Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 3/ 28

21 Low-Mass Higgs Searches H ZZ ( ) 4l (arxiv:202.45) ee Pair: µµ Pair: m µµ = 89.3 GeV m ee = 30.0 GeV High Mass Resolution (30 GeV :.5 2%) High Lepton Reconstruction Efficiency Lepton Performance Well Modeled; Independent of Pile-Up 0.2 2% Uncertainty on Signal Yield; 0.6% Uncertainty on m 4e Scale Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 4/ 28

22 Low-Mass Higgs Searches H ZZ ( ) 4l (arxiv:202.45) Events/5 GeV DATA Background Signal (m =25 GeV) H Signal (m =50 GeV) H Signal (m =90 GeV) H Syst.Unc. (*) 4l H ZZ Ldt = 4.8 fb s = 7 TeV ATLAS Events/ GeV ATLAS DATA Background Signal (m =90 GeV) H Signal (m =360 GeV) H Signal (m =520 GeV) H Syst.Unc. (*) 4l H ZZ Ldt = 4.8 fb s = 7 TeV m 4l [GeV] m 4l [GeV] Background Estimation ZZ ( ) : From Simulation Z+Jets: Control Region w/o Charge, Isolation and d 0 on 2 nd Lepton Pair t t: e ± µ Consistent with m Z + 2 Same-Flavor Leptons Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 4/ 28

23 Low-Mass Higgs Searches H ZZ ( ) 4l (arxiv:202.45) 95% CL limit on σ/σ SM 2 ATLAS (*) H ZZ 4l Ldt = 4.8 fb s=7 TeV Observed CL s Expected CL s ± σ ± 2 σ 95% CL limit on σ/σ SM 2 ATLAS (*) H ZZ 4l Ldt = 4.8 fb s=7 TeV Observed CL s Expected CL s ± σ ± 2 σ m H [GeV] m H [GeV] Expected Limit: GeV and GeV Observed Limit: GeV, GeV, GeV and GeV Local Significances: Observed (Expected w/ Signal) 25 GeV: 2.σ (.3σ) 244 GeV: 2.2σ (3.0σ) 500 GeV:.5σ (2.σ) Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 4/ 28

24 Low-Mass Higgs Searches H WW ( ) lνlν (ATLAS-CONF ) Events / GeV ATLAS Preliminary s = 7 TeV, L dt = 4.7 fb (*) H WW lνlν + 0 jets Data SM (sys stat) WW WZ/ZZ/Wγ t t Single Top Z+jets W+jets H [25 GeV] Events / GeV ATLAS Preliminary s = 7 TeV, L dt = 4.7 fb (*) H WW lνlν + jet Data SM (sys stat) WW WZ/ZZ/Wγ t t Single Top Z+jets W+jets H [25 GeV] [GeV] m T [GeV] m T Selection Two Isolated Opposite-Sign Leptons (p T > 20, 25 GeV) Large Missing Transverse Energy Jet Multiplicity (0//2 Jets), b Veto Topological Cuts (m ll, φ ll ) Additional Jet-Bin Dependent Cuts (p ll T, ptot T ) Background Estimation Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 5/ 28

25 Low-Mass Higgs Searches H WW ( ) lνlν (ATLAS-CONF ) Events / GeV ATLAS Preliminary s = 7 TeV, L dt = 4.7 fb (*) H WW lνlν + 0 jets Data SM (sys stat) WW WZ/ZZ/Wγ t t Single Top Z+jets W+jets H [25 GeV] Events / GeV ATLAS Preliminary s = 7 TeV, L dt = 4.7 fb (*) H WW lνlν + jet Data SM (sys stat) WW WZ/ZZ/Wγ t t Single Top Z+jets W+jets H [25 GeV] [GeV] m T [GeV] m T Selection Background Estimation WW: Control Sample ( φ ll, m ll ); For m H > 300 GeV from Simulation Top: Control Samples (i) no b-tagging; (ii) b-jet Tag Requirement Z+jets: m ll m Z < 5 GeV; Correcting for Mis-Modeling of ET miss W +Jets: Inverted Lepton ID Passing Loose Criteria Tail Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 5/ 28

26 Low-Mass Higgs Searches H WW ( ) lνlν (ATLAS-CONF ) 95% C.L. Limit on σ/σ SM 2 ATLAS Preliminary Observed Expected ± σ ±2 σ H WW lνlν Ldt = 4.7 fb s = 7 TeV m H [GeV] Expected Exclusion: GeV Observed Exclusion: GeV Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 5/ 28

27 Low-Mass Higgs Searches H WW ( ) lνlν (ATLAS-CONF ) 95% C.L. Limit on σ/σ SM 2 ATLAS Preliminary Observed Expected ± σ ±2 σ H WW lνlν Ldt = 4.7 fb s = 7 TeV m H [GeV] Expected Exclusion: GeV Observed Exclusion: GeV Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 5/ 28

28 Low-Mass Higgs Searches H τ τ ll/lh/hh + 4/3/2ν (ATLAS-CONF ) Channel Previously not Used in SM Higgs Analyses Separate Analyses Accordig to Jet-Category (0/-Jet, 2-Jet VH, 2-Jet VBF) Background Estimation Fake Light Leptons and τ Jets Z ττ from Embedding Technique Mass Reconstruction Collinear Approximation Missing Mass Calculator 3 Events / 2 GeV Z µµ Embedded Z µµ Data L dt = 4.7 fb s = 7 TeV ATLAS Preliminary Events / GeV eτ had + µτ had Z ττ Embedded Z ττ Alpgen MC Emb. syst. L dt = 4.7 fb s = 7 TeV ATLAS Preliminary miss E T [GeV] MMC mass m ττ [GeV] Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 6/ 28

29 Low-Mass Higgs Searches H τ τ ll/lh/hh + 4/3/2ν (ATLAS-CONF ) Channel Previously not Used in SM Higgs Analyses Separate Analyses Accordig to Jet-Category (0/-Jet, 2-Jet VH, 2-Jet VBF) Background Estimation Fake Light Leptons and τ Jets Z ττ from Embedding Technique Mass Reconstruction Collinear Approximation Missing Mass Calculator Events / 40 GeV ee + eµ + µµ H+2-jet VH Data 30 x H(20) ττ Z ττ Z ee,µµ tt+single-top WW/WZ/ZZ Fake leptons Bkg. uncert. = 7 TeV ATLAS Preliminary Collinear mass m ττ [GeV] s L dt = 4.7 fb Events / 20 GeV eτ had + µτ had H+2-jet VBF Data 5 x H(20) ττ Z ττ (OS-SS) Others (OS-SS) W+jets (OS-SS) Same Sign Bkg. uncert. = 7 TeV ATLAS Preliminary MMC mass m ττ [GeV] s L dt = 4.7 fb Events / GeV τ had τ had H+-jet Data 5 x H(20) ττ Z ττ Multi-jet Others Bkg. uncert. = 7 TeV ATLAS Preliminary Collinear mass m ττ [GeV] s L dt = 4.7 fb Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 6/ 28

30 Low-Mass Higgs Searches H τ τ ll/lh/hh + 4/3/2ν (ATLAS-CONF ) 95% CL Limit on σ/σ SM H ττ Observed CL s Expected CL s ± 2σ ± σ ATLAS Preliminary Ldt 4.7 fb s = 7 TeV [GeV] m H Observed Limit 3 times Standard Model No Significant Excess in 0 < m H < 50 GeV Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 6/ 28

31 Low-Mass Higgs Searches W/Z H, H b b (ATLAS-CONF ) Previously not Used in SM Higgs Analyses W /Z and H Recoil w/ Significant p T Analysis Sub-Divided in 4 p W/Z T Categories OR... (50/0/200 GeV) (WH lνb b and ZH llb b)... 3 ET miss Categories (20/60/200 GeV) (ZH ννb b) Exactly 2 b-tagged Jets w/ E b T > 45 GeV and Eb 2 T > 25 GeV m b b Discriminating Variable Events / GeV ATLAS Preliminary L dt=4.7 fb, s = 7 TeV ZH llbb Data 20 Signal 5 (m =20 GeV) H Total BG Top Z+jets Diboson m [GeV] bb Events / GeV 450 ATLAS Preliminary Data 20 Signal L dt=4.7 fb, s = 7 TeV (m =20 GeV) H WH lνbb Total BG 350 Top Z+jets 300 W+jets Diboson Multijet m [GeV] bb Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 7/ 28

32 Low-Mass Higgs Searches W/Z H, H b b (ATLAS-CONF ) 95% C.L. limit on σ/σ SM ATLAS Preliminary Observed (CLs) Expected (CLs) ± σ ± 2σ s=7 TeV, Ldt = fb VH(bb), combined m H [GeV] Combined Exclusion 2 5 times Standard Model Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 7/ 28

33 High-Mass Higgs Boson Searches H ZZ ( ) llνν H ZZ ( ) llq q H WW ( ) lνq q Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 8/ 28

34 High-Mass Higgs Searches H ZZ ( ) llνν (ATLAS-CONF ) Most Sensitive Channel in the High-Mass Range Discriminating Variable: Transverse Mass Pile-Up Dependent due to E miss T : Events / 30 GeV ATLAS Preliminary s = 7 TeV H ZZ llνν Low pile-up data Data L dt = 2.3 fb Total BG Top ZZ,WZ,WW Z,W Signal (m = 200 GeV) H Events / 50 GeV ATLAS Preliminary s = 7 TeV H ZZ llνν High pile-up data Data L dt = 2.4 fb Total BG Top ZZ,WZ,WW Z,W Signal (m = 400 GeV) H [GeV] m T [GeV] m T Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 9/ 28

35 High-Mass Higgs Searches H ZZ ( ) llνν (ATLAS-CONF ) Most Sensitive Channel in the High-Mass Range Discriminating Variable: Transverse Mass Pile-Up Dependent due to E miss T : Events / 30 GeV ATLAS Preliminary s = 7 TeV H ZZ llνν Low pile-up data Data L dt = 2.3 fb Total BG Top ZZ,WZ,WW Z,W Signal (m = 200 GeV) H Events / 50 GeV ATLAS Preliminary s = 7 TeV H ZZ llνν High pile-up data Data L dt = 2.4 fb Total BG Top ZZ,WZ,WW Z,W Signal (m = 400 GeV) H [GeV] m T [GeV] m T Background Estimation ZZ: From Simulation (% Normalization Uncertainty) WZ: Estimated from Three-Lepton Events t t: From Simulation (Veryfied in eµ+ b-jet Data or m ll Sidebands) W+Jets: Like-Sign ee and eµ Events in m ll Sideband + 0 b-jets Z+Jets: Low φ( p T miss, pjet T ) Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 9/ 28

36 High-Mass Higgs Searches H ZZ ( ) llνν (ATLAS-CONF ) 95% CL limit on σ/σ SM ATLAS Preliminary H ZZ llνν Ldt=4.7fb, s=7tev Observed Expected ± σ ± 2σ m H [GeV] Expected Exclusion: GeV Observed Exclusion: GeV Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 9/ 28

37 High-Mass Higgs Searches H ZZ ( ) llqq (ATLAS-CONF ) Analyses Categorized According to b-tag m lljj as Discriminating Variable Entries / 20 GeV ATLAS Preliminary L dt=4.7 fb, s = 7 TeV data Signal 5 (m =400 GeV) H Total BG Z + jets Top Diboson [GeV] m lljj Entries / 50 GeV ATLAS Preliminary 8 data L dt=4.7 fb, s = 7 TeV Signal 7 (m =400 GeV) H Total BG 6 Z + jets Top 5 Diboson [GeV] m lljj Background Estimation Z+Jets/Top: Normalized from m jj Sidebands; Shape from Simulation Di-Boson: Taken from Simulation Multijets: Reverted Electron-ID Criteria Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 20/ 28

38 High-Mass Higgs Searches H ZZ ( ) llqq (ATLAS-CONF ) 95% CL limit on σ/σ SM ATLAS Preliminary Observed Expected H ZZ llqq ± σ 8 Ldt = 4.7 fb, s=7 TeV ± 2 σ m H [GeV] Expected Exclusion: GeV Observed Exclusion: GeV and GeV Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 20/ 28

39 High-Mass Higgs Searches H WW ( ) lνqq (ATLAS-CONF ) Analysis Split into 0/-Jet and 2-Jet (VBF) Category Discriminating Variable m lνqq with m lν = m W and m qq = m W Search for Bump above Steeply-Falling Background (Modeled from Fit to Data) Major Systematic Uncertainties: Jet-Energy Scale ( 20%); Pile-Up ( 5%) Entries / 20 GeV L dt = 4.7 fb 3 Data s = 7 TeV Total bkg (stat sys) H + 0j, H eν qq W+jets 2 ATLAS Preliminary Z+jets Dibosons Multi-jet Top SM Signal (m = 400 GeV) H Entries / 20 GeV 2 L dt = 4.7 fb s = 7 TeV H + 2j, H µν qq ATLAS Preliminary Data Total bkg (stat sys) W+jets Z+jets Dibosons Multi-jet Top SM Signal x m H = 400 GeV Data / MC m WW [GeV] Data / MC m [GeV] m WW [GeV] Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 2/ 28

40 High-Mass Higgs Searches H WW ( ) lνqq (ATLAS-CONF ) Analysis Split into 0/-Jet and 2-Jet (VBF) Category Discriminating Variable m lνqq with m lν = m W and m qq = m W Search for Bump above Steeply-Falling Background (Modeled from Fit to Data) Major Systematic Uncertainties: Jet-Energy Scale ( 20%); Pile-Up ( 5%) 95% C.L. limit on σ/σ(sm) 2 Expected ± σ ± 2σ Observed s=7 TeV L dt=4.7 fb H WW lν jj ATLAS Preliminary m H [GeV] Limit 2 Times Standard Model Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 2/ 28

41 Combination 95% CL limit on σ/σ SM Exp. Obs. Exp. Obs. H γγ H γγ (4.9 fb(4.9 ) fb ) H ττ H ττ (4.7 fb(4.7 ) fb ) H bb H ( bb ( fb ) fb ) H WW H WW lνlν lνlνfb(4.7 ) fb ) H WW H WW lνqq (4.7 lνqq fb(4.7 ) fb ) H ZZ H llll ZZ (4.8 llll fb(4.8 ) fb ) H ZZ H llqq ZZ (4.7 llqq fb(4.7 ) fb ) H ZZ H llνν ZZ (4.7 llννfb(4.7 ) fb ) L dt ~ fb, s=7 TeV ATLAS 20 Preliminary CLs limits m H [GeV] Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 22/ 28

42 Combination Combined Exclusion Limit 95% CL Limit on σ/σ SM ATLAS Preliminary Obs. Exp. ± σ ±2 σ Ldt = fb s = 7 TeV 20 Data 95% CL Limit on σ/σ SM Obs. Exp. Ldt = fb ± σ ± 2 σ s = 7 TeV ATLAS Preliminary 20 Data CLs Limits m H [GeV] CLs Limits m H [GeV] Excluded Mass Range Expected (95% CL): 20 < m H < 550 GeV Observed (95% CL): < m H < 7.5 GeV and 8.5 < m H < 22.5 GeV and 29 < m H < 539 GeV Observed (99% CL): 30 < m H < 486 GeV Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 22/ 28

43 Combination Combined Exclusion Limit 95% CL Limit on σ/σ SM ATLAS Preliminary Obs. Exp. ± σ ±2 σ Ldt = fb s = 7 TeV 20 Data 95% CL Limit on σ/σ SM Obs. Exp. Ldt = fb ± σ ± 2 σ s = 7 TeV ATLAS Preliminary 20 Data CLs Limits m H [GeV] CLs Limits m H [GeV] Excluded Mass Range Expected (95% CL): 20 < m H < 550 GeV Observed (95% CL): < m H < 7.5 GeV and 8.5 < m H < 22.5 GeV and 29 < m H < 539 GeV Observed (99% CL): 30 < m H < 486 GeV Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 22/ 28

44 Combination Testing µ = Hypothesis CLs ATLAS Preliminary Obs. Exp. Ldt = fb s = 7 TeV 20 Data m H [GeV] 95% 99% CLs ATLAS Preliminary Obs. Exp. Ldt = fb s = 7 TeV 20 Data m H [GeV] 95% 99% Excluded Mass Range Expected (95% CL): 20 < m H < 550 GeV Observed (95% CL): < m H < 7.5 GeV and 8.5 < m H < 22.5 GeV and 29 < m H < 539 GeV Observed (99% CL): 30 < m H < 486 GeV Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 22/ 28

45 Combination 0 0 Breakdown of the Observed Excess Local p ATLAS Preliminary Obs. Exp m H [GeV] s = 7 TeV 20 Data Ldt = fb σ 2σ 3σ 4σ 5σ Local p ATLAS Preliminary Obs. Exp. Ldt = fb s = 7 TeV 20 Data m H [GeV] σ 2σ 3σ 4σ 5σ 26 GeV Observed local Significance: 2.6σ (2.9σ Expected) Probability to Observe such Fluctuation in... < m H < 600 GeV: 30%... < m H < 46 GeV: % Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 22/ 28

46 Combination Excess in Individual Channels 0 Local p ATLAS Preliminary Obs. γγ+4l Exp. γγ+4l Obs. γγ+4l+lνlν Exp. γγ+4l+lνlν Obs. Exp m H [GeV] 20 Data Ldt = fb s = 7 TeV σ 2σ 3σ 4σ 5σ Excess mainly in H γγ and H ZZ ( ) 4l Local Significance: 3.4σ NO Excess in H WW ( ) lνlν, H ττ, and H b b Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 22/ 28

47 Combination Excess in Individual Channels 0 Local p ATLAS Preliminary Obs. γγ+4l Exp. γγ+4l Obs. γγ+4l+lνlν Exp. γγ+4l+lνlν Obs. Exp m H [GeV] 20 Data Ldt = fb s = 7 TeV σ 2σ 3σ 4σ 5σ Excess mainly in H γγ and H ZZ ( ) 4l Local Significance: 3.4σ NO Excess in H WW ( ) lνlν, H ττ, and H b b All Channels Combined: 3.4σ Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 22/ 28

48 Outline The ATLAS Detector and Performance 2 Standard Model Higgs Searches The Standard Model Higgs Boson Low-Mass Higgs Searches High-Mass Higgs Searches Combination of Standard Model Results 3 Higgs Searches Beyond the Standard Model Fermiophobic Higgs MSSM Neutral Higgs Charged Higgs Doubly-Charged Higgs Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 23/ 28

49 BSM Higgs Searches Fermiophobic Higgs (ATLAS-CONF ) Decreased Coupling to Some or All Fermions in Higgs Doublet and Triplet Models Production via VBF or VH Decays to γγ, WW, ZZ, Zγ Analysis Identical to that in the SM 9 Analysis Categories (η Conversion Status p γγ(thrust) T ) Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 24/ 28

50 BSM Higgs Searches Fermiophobic Higgs (ATLAS-CONF ) Decreased Coupling to Some or All Fermions in Higgs Doublet and Triplet Models Production via VBF or VH Decays to γγ, WW, ZZ, Zγ Analysis Identical to that in the SM 9 Analysis Categories (η Conversion Status p γγ(thrust) T ) Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 24/ 28

51 BSM Higgs Searches Fermiophobic Higgs (ATLAS-CONF ) Expected Exclusion: 23.5 GeV Observed Exclusion: 8 GeV and GeV Largest m H = 25.5 GeV Statistical Significance.6σ (Including Look-Elsewhere Effect) Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 24/ 28

52 BSM Higgs Searches MSSM Phenomenology Two Higgs Doublets Five Physical Higgs Bosons: h/h (CP=+), A (CP=), H ± Tree-Level: Two Free Parameters (m A, tan β) h Standard-Model like At least Two Higgs Bosons Mass-Degenerate Production Cross Section Function Scales as tan 2 β Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 25/ 28

53 BSM Higgs Searches MSSM Phenomenology Two Higgs Doublets Five Physical Higgs Bosons: h/h (CP=+), A (CP=), H ± Tree-Level: Two Free Parameters (m A, tan β) h Standard-Model like At least Two Higgs Bosons Mass-Degenerate Production Cross Section Function Scales as tan 2 β Production and Decay of MSSM Higgs Bosons Neutral Higgs Bosons (h/h/a) Gluon-Fusion or b-quark Associate Production g g b b g b q b φ φ φ g φ g b Cross Section O(fb pb) Branching Fraction to τ-leptons BR = O(%) (b b (BR 90%) Channel Extremely Challenging) b φ g b q b Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 25/ 28

54 BSM Higgs Searches MSSM Neutral Higgs (ATLAS-CONF-2032) Analysis of All Final States (eµ, e/µ τ had, τ had τ had ) Dominant Backgrounds Estimated from Control Regions W/Z+Jets Using Embedding Technique QCD from Same-Sign Control Region Varying Mass Reconstruction Techniques (m vis, m eff, MMC) Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 25/ 28

55 BSM Higgs Searches MSSM Neutral Higgs (ATLAS-CONF-2032) σ BR m A vs. tan β Assume only one Resonance 0% gg H or 0% b bh Useful to Test Arbitrary Models Have to Assume Specific (c)mssm Model Here: m max h Scenario Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 25/ 28

56 BSM Higgs Searches Charged Higgs (ATLAS-CONF-202-0) Predicted in Higgs Doublet or Triplet Models m H ± < m top: Produced Predominantly in Top Decays tan β > 3: Decays to τν Preferred Channels Analyzed W q q, H ± τ had ν W q q /lν, H ± τ lep ν Lepton+Jets Tau+Lepton Tau+Jets cos Θ l = 4p b p l mtop 2 m2 W q 2 (mt H )2 = mtop 2 + (pl T + pb T pmiss T )2 pt«b p l T + pmiss T 2 Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 26/ 28

57 BSM Higgs Searches Charged Higgs (ATLAS-CONF-202-0) Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 26/ 28

58 BSM Higgs Searches Doubly-Charged Higgs (arxiv:20.9) Relevant in Higgs Triplet, Little Higgs, and Left-Right Symmetric Models Select Pairs of Same-Charge Muons with p T.20 GeV Look for Resonance in Di-Muon Spectrum No Significant Excess above Expected Background Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 27/ 28

59 Summary Excellent ATLAS Performance from Detector to Physics (6 Papers Submitted or Published) Scalar/Charged Boson Searches in many Inclusive/Exclusive Channels, Using full 20 Data Set Allowed Scalar Boson Mass in the Standard Model GeV or GeV In SM Low-Mass Region No Exclusion Possible Due to an Excess of Observed Events Compared to Background-Only Expectation Observed Excess of Events at m H 26 GeV Compatible with Hypothesis of a Standard Model Higgs Boson (Statistical Significance not yet Large enough) Data to be Collected in 202 Might Give the Final Answer to SM Higgs Boson Wolfgang F. Mader (TU Dresden) Higgs Boson Searches in ATLAS 28/ 28