Constraints on new phenomena through Higgs coupling measurements and invisible decays with the ATLAS detector G. Carrillo-Montoya on behalf of the ATLAS Collaboration EPS-HEP-2015 Vienna - Austria July 24th - 2015 - CERN, G. Carrillo-Montoya EPS - Vienna 2015 1/19
NEW https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HIGG-2015-03
Combination of Higgs Measurements (now with ttH !!!) σ (stat.) ATLAS Total uncertainty sys inc. σ ( ) ± σ µ theory m = 125.36 GeV 1 on ATLAS H σ (theory) √ s = 7 TeV, 4.5 − 4.7 fb −1 68% CL: 0.23 → γ γ + H √ s = 8 TeV, 20.3 fb −1 0.23 95% CL: - + 0.16 µ 0.28 + - 0.11 = 1.17 + 0.12 - 0.26 - 0.08 μ ggF = 1.23 +0.23 0.35 → + −0.20 H ZZ* 0.31 - + 0.19 µ 0.40 0.13 μ VBF = 1.23 ± 0.32 = 1.46 + - + 0.18 - 0.34 0.11 - 0.16 μ VH = 0.80 ± 0.36 → + H WW* 0.16 - + 0.17 µ 0.24 0.14 = 1.18 + - μ ttH = 1.81 ± 0.80 + 0.13 - 0.21 0.09 m H = 125.36 GeV - 0.30 → τ τ + H 0 0.5 1 1.5 2 2.5 3 - 0.29 0.29 + Signal strength ( μ ) µ 0.42 0.23 = 1.44 + - + 0.16 0.37 - 0.10 - 7 0.31 VBF+VH + → H b b - 0.30 Standard Model ATLAS 0.24 + 6 µ 0.39 0.23 = 0.63 + - Best fit -1 0.09 f s = 7 TeV, 4.5-4.7 fb + µ 0.37 - 0.07 68% CL -1 - s = 8 TeV, 20.3 fb 5 → µ µ 3.6 95% CL + H - 3.6 → H WW* 0.5 + 4 → µ 3.7 0.7 H ZZ* = -0.7 + - 0.4 + 3.7 H → bb - 0.4 - 3 → γ + 4.3 → γ γ H Z H - 4.2 → τ τ 1.7 H + 2 µ + 4.6 - 1.3 = 2.7 1.1 + 4.5 - - 0.3 1 0.10 + Combined 0 0.10 - + 0.11 µ 0.15 0.10 + - − = 1.18 1 0.08 + 0.14 - - 0.07 m = 125.36 GeV H − 2 − − − 2 1 0 1 2 3 4 5 6 7 1 0 1 2 3 -1 s = 7 TeV, 4.5-4.7 fb µ f ggF+ttH µ Signal strength ( ) -1 s = 8 TeV, 20.3 fb arXiv:1507.04548 - CERN, G. Carrillo-Montoya EPS - Vienna 2015 3/19
Higgs boson Coupling measurements ( κ -framework) 4 F κ ATLAS 3 Disentangle individual couplings -1 s = 7 TeV, 4.5-4.7 fb -1 s = 8 TeV, 20.3 fb from production and decays 2 m = 125.36 GeV H Assumptions 1 (LO-inspired benchmark) 0 arxiv:1307.1427): − 1 Higgs → single resonance → γ γ H − 2 → H ZZ* Narrow width approximation → H WW* → τ τ − H σ × BR ( i → H → f ) = σ i · Γ f 3 SM 68% CL → H bb Γ H Best fit 95% CL Combined − 4 No modification on the Tensor 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 structure of the couplings (only κ In V absolute values are modified) this plot, no invisible/undetected decays Acceptance unchanged assumed Factors κ i such as κ 2 κ 2 g ˙ σ × BR ( gg → H → γγ ) γ ( σ gg × BR ( H → γγ )) SM = Note that κ 2 g and κ 2 γ are loop-induced κ 2 h depending on ( κ t , κ b and κ W ). - CERN, G. Carrillo-Montoya EPS - Vienna 2015 4/19
Higgs couplings and internal structure Mass scaling Constrains on Multiple Higgs bosons Minimal Composite Higgs Model Probing Invisible Higgs boson decays Content Higgs couplings and internal structure 1 Mass scaling Minimal Composite Higgs Model Constrains on Multiple Higgs bosons 2 Real Electroweak Singlet 2HDM Simplified MSSM Probing Invisible Higgs boson decays 3 Direct (Invisible) searches Combination of indirect (visible channels) and direct (invisible searches) - CERN, G. Carrillo-Montoya EPS - Vienna 2015 5/19
Higgs couplings and internal structure Mass scaling Constrains on Multiple Higgs bosons Minimal Composite Higgs Model Probing Invisible Higgs boson decays “Mass scaling” of couplings Each coupling in terms of vev ( v ≈ 246 GeV) and ǫ (note that SM: ǫ → 0) m ǫ m 2 ǫ ε : 0 . 018 ± 0 . 039 , M : 224 + 14 κ f , i = v f , i κ V , j = v V , j − 12 GeV M 1 + ǫ M 1 + 2 ǫ V M [GeV] m v ATLAS Preliminary ATLAS t 300 V 1 κ -1 s = 7 TeV, 4.5-4.7 fb -1 Z s = 7 TeV, 4.5-4.7 fb or -1 s = 8 TeV, 20.3 fb -1 280 s = 8 TeV, 20.3 fb F W m v Best fit -1 Observed 10 Obs. 68% CL F κ SM Expected Obs. 95% CL 260 SM Exp. 68% CL Exp. 95% CL -2 240 10 τ b 220 µ -3 10 200 -1 2 0.1 0 0.1 0.2 0.3 0.4 10 1 10 10 − Particle mass [GeV] ∈ arXiv:1507.04548 HIGGS-2015-03 - CERN, G. Carrillo-Montoya EPS - Vienna 2015 6/19
Higgs couplings and internal structure Mass scaling Constrains on Multiple Higgs bosons Minimal Composite Higgs Model Probing Invisible Higgs boson decays Minimal Composite Higgs Model Scalar Naturalness: Higgs → composite pseudo Nambu-Goldstone boson 95% CL obs (exp): MCHM4: f > 710 (510) GeV; MCHM5: f > 780 (600) GeV Higgs couplings modified F 1.8 κ ATLAS Preliminary as function of -1 1.6 s = 7 TeV, 4.5-4.7 fb compositeness scale f -1 s = 8 TeV, 20.3 fb ξ = v 2 / f 2 1.4 1.2 MCHM4 - MCHM4: ξ =0.1 ξ =0.0 1 κ = κ V = κ F = √ 1 − ξ ξ =0.2 ξ =0.3 0.8 ξ =0.1 - MCHM5: κ V = √ 1 − ξ 0.6 ξ =0.2 Best fit SM ξ =0.3 MCHM5 Obs. 68% CL Exp. 68% CL 1 − 2 ξ √ 0.4 κ F = Obs. 95% CL Exp. 95% CL 1 − ξ 0.8 0.9 1 1.1 1.2 1.3 SM recovered in the limit κ V ξ → 0, namely f → ∞ . - CERN, G. Carrillo-Montoya EPS - Vienna 2015 7/19
Higgs couplings and internal structure Real Electroweak Singlet Constrains on Multiple Higgs bosons 2HDM Probing Invisible Higgs boson decays Simplified MSSM Content Higgs couplings and internal structure 1 Mass scaling Minimal Composite Higgs Model Constrains on Multiple Higgs bosons 2 Real Electroweak Singlet 2HDM Simplified MSSM Probing Invisible Higgs boson decays 3 Direct (Invisible) searches Combination of indirect (visible channels) and direct (invisible searches) - CERN, G. Carrillo-Montoya EPS - Vienna 2015 8/19
Higgs couplings and internal structure Real Electroweak Singlet Constrains on Multiple Higgs bosons 2HDM Probing Invisible Higgs boson decays Simplified MSSM Additional Real Electroweak Singlet Simplest extension: additional real EW singlet, m H heavier than 125 GeV Couplings → mixing gives: κ 2 + κ ′ 2 = 1 Coupling (and signal strength as predicted by heavier SM-like Higgs) modified by allowing new decays BR H , new , like H → hh ATLAS Preliminary EW singlet -1 s = 7 TeV, 4.5-4.7 fb SM -1 s = 8 TeV, 20.3 fb 2 Obs. 95% CL: κ ’ <0.12 Exp. 95% CL: ’ 2 <0.23 κ 1 H,new 0.9 Γ / Γ H =1.0 H,SM Γ Γ / 0.8 Γ BR / H H Γ H , =0.3 S M Γ H 0.7 , S H M =0.15 / Γ H 0.6 , S M =0.05 0.5 0.4 =0.1 µ =0.15 0.3 =0.05 =0.025 =0.075 H µ H 0.2 µ H µ H 0.1 H µ 0 0 0.05 0.1 0.15 0.2 0.25 2 ’ κ κ ′ 2 < 0 . 12 ( 0 . 23 ) 95%CL: - CERN, G. Carrillo-Montoya EPS - Vienna 2015 9/19
Higgs couplings and internal structure Real Electroweak Singlet Constrains on Multiple Higgs bosons 2HDM Probing Invisible Higgs boson decays Simplified MSSM Two Higgs Doublet Model Two identical complex scalar fields( SU ( 2 ) ) The 2HDM scalar potential → Z 2 broken symmetry In the CP-conserving case, parameters can be reduced to 6: 4 masses m h , m H , m H ± , m A , and 2 angles α , β 2 = v 2 ≈ ( 246 GeV ) 2 tan β = v 1 / v 2 : ratio of vevs (satisfying v 2 1 + v 2 α : mixing angle between h and H Coupling Type I Type II Type III Type IV scale factor (fermiophobic) (MSSM-like) (lep. specific) (flipped) κ V sin ( β − α ) sin ( β − α ) sin ( β − α ) sin ( β − α ) κ u cos ( α ) / sin ( β ) cos ( α ) / sin ( β ) cos ( α ) / sin ( β ) cos ( α ) / sin ( β ) κ d cos ( α ) / sin ( β ) − sin ( α ) / cos ( β ) cos ( α ) / sin ( β ) − sin ( α ) / cos ( β ) κ l cos ( α ) / sin ( β ) − sin ( α ) / cos ( β ) − sin ( α ) / cos ( β ) cos ( α ) / sin ( β ) Assumptions (for interpretations): 125 GeV is the light higgs, no radiative corrections, only SM decays. Convention: sin ( β − α ) ≥ 0 SM-like alignment limit retrieved at cos ( β − α ) = 0 - CERN, G. Carrillo-Montoya EPS - Vienna 2015 10/19
Higgs couplings and internal structure Real Electroweak Singlet Constrains on Multiple Higgs bosons 2HDM Probing Invisible Higgs boson decays Simplified MSSM Two Higgs Doublet Model, Type I and II ATLAS Preliminary ATLAS Preliminary 2HDM Type II 2HDM Type I Obs. 95% CL Obs. 95% CL -1 -1 s = 7 TeV, 4.5-4.7 fb s = 7 TeV, 4.5-4.7 fb Best fit Best fit -1 s = 8 TeV, 20.3 fb -1 s = 8 TeV, 20.3 fb Exp. 95% CL Exp. 95% CL SM SM 10 β 10 β tan tan 4 4 3 3 2 2 1 1 0.4 0.4 0.3 0.3 0.2 0.2 − 1 10 − 1 10 − 1 − 0.8 − 0.6 − 0.4 − 0.2 0 0.2 0.4 0.6 0.8 1 − 1 − 0.8 − 0.6 − 0.4 − 0.2 0 0.2 0.4 0.6 0.8 1 cos( β - α ) cos( β - α ) - CERN, G. Carrillo-Montoya EPS - Vienna 2015 11/19
Higgs couplings and internal structure Real Electroweak Singlet Constrains on Multiple Higgs bosons 2HDM Probing Invisible Higgs boson decays Simplified MSSM 2HDM, Lepton Specific & Flipped ATLAS Preliminary ATLAS Preliminary 2HDM Lepton-specific 2HDM Flipped Obs. 95% CL Obs. 95% CL -1 -1 s = 7 TeV, 4.5-4.7 fb s = 7 TeV, 4.5-4.7 fb Best fit Best fit -1 -1 s = 8 TeV, 20.3 fb s = 8 TeV, 20.3 fb Exp. 95% CL Exp. 95% CL SM SM 10 β 10 β tan tan 4 4 3 3 2 2 1 1 0.4 0.4 0.3 0.3 0.2 0.2 − 1 − 1 10 10 − 1 − 0.8 − 0.6 − 0.4 − 0.2 0 0.2 0.4 0.6 0.8 1 − 1 − 0.8 − 0.6 − 0.4 − 0.2 0 0.2 0.4 0.6 0.8 1 cos( β - α ) cos( β - α ) - CERN, G. Carrillo-Montoya EPS - Vienna 2015 12/19
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