Higgs boson properties (ATLAS and CMS)

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1 Higgs boson properties (ATLAS and CMS) Marcello Fanti [University of Milano and INFN] (on behalf of the ATLAS and CMS collaborations) M. Fanti (Physics Dep., UniMi) Higgs boson properties / 8

2 -- Run-II : Higgs boson strikes back! H γγ weights / GeV weights - bkg Data Background Signal Background Signal ATLAS Preliminary s = 3 TeV, 3.3 fb H γγ, m = 5.9 GeV H S/B weighted sum of event categories m γγ [GeV] S/(SB) Weighted Events / GeV 5 3 CMS Preliminary H γγ m H =6. GeV, µ=.95.9 fb (3 TeV) All categories S/(SB) weighted Data SB fit B component ± σ ± σ B component subtracted m γγ (GeV) Events/.5 GeV 35 Data ATLAS Preliminary Higgs (m = 5 GeV) 3 H ZZ* l 3 TeV,.8 fb H ZZ* Zjets, tt ttv, VVV Uncertainty 5 Events / GeV CMS Preliminary.9 fb (3 TeV) Data H(5) qq ZZ, Zγ* gg ZZ, Zγ* ZX H l [GeV] m l (GeV) m l M. Fanti (Physics Dep., UniMi) Higgs boson properties / 8

3 Higgs boson production at LHC σ(pp HX) [pb] M(H)= 5 GeV pp H (N3LO QCD NLO EW) pp qqh (NNLO QCD NLO EW) pp WH (NNLO QCD NLO EW) pp ZH (NNLO QCD NLO EW) pp bbh (NNLO QCD in 5FS, NLO QCD in FS) pp tth (NLO QCD NLO EW) pp th (NLO QCD, t-ch s-ch) LHC HIGGS XS WG 6 QCD production EW production s [TeV] Experimental identification of VBF and VH productions ( tagging ): τ forward tag jet b-jet µ p p p p forward tag jet τ b-jet µ M. Fanti (Physics Dep., UniMi) Higgs boson properties 3 / 8

4 Higgs at LHC : Run-I vs Run-II Cross-section vs s s = 8 TeV 3 TeV cross-sections increase: ggf, VBF by.3 tth by 3.8 ] Delivered Luminosity [fb ATLAS Online Luminosity pp pp 5 pp 6 pp s = 7 TeV s = 8 TeV s = 3 TeV s = 3 TeV 7/6 calibration σ(pp HX) [pb] M(H)= 5 GeV pp H (N3LO QCD NLO EW) pp qqh (NNLO QCD NLO EW) pp WH (NNLO QCD NLO EW) pp ZH (NNLO QCD NLO EW) pp bbh (NNLO QCD in 5FS, NLO QCD in FS) pp tth (NLO QCD NLO EW) pp th (NLO QCD, t-ch s-ch) s [TeV] Luminosity per experiment In Run-I 5 fb In 5 3 fb In 6 fb and rising fast! ( 9 5 fb analysed) LHC HIGGS XS WG 6 Jan Apr Jul Oct Month in Year M. Fanti (Physics Dep., UniMi) Higgs boson properties / 8

5 Higgs boson decay modes For a mass m H 5 GeV, several decay modes are kinematically accessible a thorough study of its properties is possible Higgs BR Total Uncert 3 ττ cc µµ bb γγ gg Zγ WW ZZ LHC HIGGS XS WG 3 If it is the Standard Model Higgs boson, its properties are: spin-parity : J CP = couplings to vector bosons : g V = m V υ couplings to fermions : g f = m f υ M H [GeV] can probe several couplings and J CP states Observation of H γγ C = and J (Landau-Yang theorem) M. Fanti (Physics Dep., UniMi) Higgs boson properties 5 / 8

6 Higgs at LHC : Run-I vs Run-II Mass measurement From run-i, combined ATLASCMS measurement Now repeated at Run-II Cross-sections, Couplings Fiducial and total cross-sections at 7, 8, 3 TeV Couplings from run-i combined ATLASCMS measurement, and being repeated in Run-II tth production and H b b Spin and CP properties, width, differential cross-sections From Run-I, being repeated in Run-II M. Fanti (Physics Dep., UniMi) Higgs boson properties 6 / 8

7 Mass measurement [arxiv: v [hep-ex] 6 Mar 5 PRL (5) 983] M. Fanti (Physics Dep., UniMi) Higgs boson properties 7 / 8

8 Mass measurement Using the H γγ and H ZZ l decay channels that allow a full kinematics reconstruction with good invariant mass resolution (O ( GeV)) (main source of systematic: energy scale) ATLAS and CMS Run Total Stat. Syst. LHC Total Stat. Syst. ATLAS H γ γ 6. ±.5 ( ±.3 ±.7) GeV CMS H γ γ.7 ±.3 ( ±.3 ±.5) GeV ATLAS H ZZ l.5 ±.5 ( ±.5 ±.) GeV CMS H ZZ l 5.59 ±.5 ( ±. ±.7) GeV ATLAS CMS γ γ 5.7 ±.9 ( ±.5 ±.) GeV ATLAS CMS l 5.5 ±. ( ±.37 ±.5) GeV ATLAS CMS γ γ l 5.9 ±. ( ±. ±.) GeV ˆm H m H = 5.9 ±.(stat) ±.(syst) GeV [GeV] M. Fanti (Physics Dep., UniMi) Higgs boson properties 8 / 8

9 Mass 3 TeV - lnl CMS Preliminary.9 fb (3 TeV) 5 3 µ eµ e Combined Combined (stat. only) CMS, H l channel m H (GeV) ˆm H = (stat).3.5 (syst) GeV M. Fanti (Physics Dep., UniMi) Higgs boson properties 9 / 8

10 Importance of mass measurement In the Standard Model, m H is the only free parameter of the Higgs sector The Higgs sector has two parameters: µ and λ related to the VEV υ and the Higgs mass m H by: µ = m H and λ = ( mh ). Since υ = is known, υ GF m H is the only free parameter. cross-section decay width branching ratios σ(pp HX) [pb] pp HX at s= TeV pp HX at s=8 TeV LHC HIGGS XS WG Γ H [GeV] 3 LHC HIGGS XS WG Higgs BR Total Uncert ττ cc bb gg WW ZZ tt LHC HIGGS XS WG pp HX at s=7 TeV γγ Zγ M H [GeV] 3 5 M H [GeV] M H [GeV] everything else is calculable, once m H is given. [ M. Fanti (Physics Dep., UniMi) Higgs boson properties / 8

11 Cross sections M. Fanti (Physics Dep., UniMi) Higgs boson properties / 8

12 Cross-section from γγ and l final states [CMS-PAS-HIG6-33, CMS-PAS-HIG6-] Fiducial cross-section vs s H l [fb] σ fid fb (7 TeV), 9.7 fb (8 TeV),.9 fb (3 TeV) CMS Preliminary Data (stat. sys. unc.) Systematic uncertainty Model dependence 3 Standard model (m = 5 GeV, N LO gg H) H H γγ (fb) σ fid CMS Preliminary H γγ Data (best-fit m H ) syst. uncertainty SM (m H =5.9 GeV) - norm. LHC Higgs XSWG YR - acc. AMC@NLO 9.7 fb (8 TeV).9 fb (3 TeV) pp (H l) X s (TeV) Improved theory calculations for gluon fusion: Run-I: NNLONNLL: ±8% from scale and ±7% from α S PDF Run-II: N3LO: ±% from scale and ±3% from α S PDF... now experiments need to catch up! s (TeV) M. Fanti (Physics Dep., UniMi) Higgs boson properties / 8

13 f f Cross-section from γγ and l final states [ATLAS-CONF-6-8] Total cross-section vs s (γγ and l combined) [pb] σ pp H ATLAS Preliminary σ pp H m H = 5.9 GeV 8 6 H γ γ H ZZ * l comb. data syst. unc. QCD scale uncertainty Tot. uncert. (scale PDFα s ) Cross-section for ggf vs VBF SM [pb] (σ B) /B VBF ATLAS Preliminary s=3 TeV, 3.3 fb (γγ),.8 fb (ZZ) = 5.9 GeV m H SM Best fit 68% CL 95% CL H γγ H ZZ* l 3 s = 7 TeV,.5 fb s = 8 TeV,.3 fb s = 3 TeV, 3.3 fb (γ γ ),.8 fb (ZZ *) 6 8 (σ B) / Bf [pb] f ggf SM s [TeV] M. Fanti (Physics Dep., UniMi) Higgs boson properties 3 / 8

14 Measurements of couplings [arxiv:66.66v [hep-ex] 7 Jun 6 accepted by JHEP] M. Fanti (Physics Dep., UniMi) Higgs boson properties / 8

15 Couplings the κ-framework Reminder: in SM Higgs couplings are g SM f = m f υ and g SM V = m V υ i o Couplings are accessible through production (ii H) and decay (H oo) Define couplings modifiers κ x = g x g SM x H SM κ i g i κ o g o SM σ ii H oo = σ SM ii H oo κ i κ o κ H i o (κ def H = Γ H Γ SM if no BSM decays, κ H = κ obrh oo) SM H o (... otherwise need to allow one extra free parameter, BR to new physics, B BSM see later on) Several couplings: κ µ, κ τ, κ b, κ W, κ Z, κ t... effective couplings: κ g, κ γ... Assume weak gauge boson universality: κ W = κ Z = κ V and fermion universality: κ t = κ b = κ τ = κ f g t, b H H W H W Loop-mediated interactions described as in SM: gg H (mainly) through top/bottom virtual loop κ g = κ t,b = κ f g H t H γγ through top and W virtual loops κ γ = (.6 κ W.6 κ t ) = (.6 κ V.6 κ f ) M. Fanti (Physics Dep., UniMi) Higgs boson properties 5 / 8

16 (Universal) couplings to fermions and weak bosons κ f F ATLAS and CMS LHC Run Combined H γγ H ZZ H WW H ττ H bb Exploit final state topologies (e.g. VBF, VH) measure κ V, κ f for each decay channel then combine decay channels.5 all measurements compatible with SM prediction ( ) (κ V =, κ f = ) 68% CL 95% CL Best fit SM expected.5.5 κf V M. Fanti (Physics Dep., UniMi) Higgs boson properties 6 / 8

17 Relaxing some assumptions Testing the EW symmetry breaking: λ WZ = κ W κ Z λ du = κ d κ u Testing up/down and lepton/quark universality (would be broken in -Higgs-doublet models) λ lq = κ l κ q ln Λ 9 8 ATLAS and CMS [κ gz, λ WZ, λ Zg, λ bz, λ γz, λ τz, λ tg ] LHC Run Observed SM expected ln Λ 9 8 ATLAS and CMS [κ uu, λ Vu, λ du ] LHC Run Observed SM expected ln Λ 9 8 ATLAS and CMS [κ qq, λ Vq, λ lq ] LHC Run Observed SM expected λ WZ λ du λ lq M. Fanti (Physics Dep., UniMi) Higgs boson properties 7 / 8

18 Testing the ggh and Hγγ interactions g H H H ggh and Hγγ interactions in SM are mediated by loops particularly sensitive to new particles in the loops g H κ g.6 ATLAS and CMS LHC Run ATLASCMS ATLAS CMS.. consider κ g, κ γ as free and profile others again, compatibility with SM ( ) % CL 95% CL Best fit SM expected κ γ M. Fanti (Physics Dep., UniMi) Higgs boson properties 8 / 8

19 Summary of the rates (wrt Standard Model predictions) tth ZH WH VBF ggf γγ ZZ WW ττ γγ ZZ WW ττ γγ WW ττ bb γγ WW ττ bb γγ WW ττ ATLAS and CMS LHC Run Observed ±σ Th. uncert. bb σ B norm. to SM prediction σ(gg H ZZ) σ /σ VBF ggf σ /σ WH ggf σ /σ ZH ggf σ /σ tth ggf WW ZZ B /B γ γ ZZ B /B ττ ZZ B /B bb ZZ B /B ATLAS and CMS LHC Run ATLASCMS ATLAS CMS ±σ ±σ Th. uncert Parameter value norm. to SM prediction M. Fanti (Physics Dep., UniMi) Higgs boson properties 9 / 8

20 Summary of the couplings v V m κ V ATLAS and CMS LHC Run W Z t or v F m κ F τ b Recall: in SM g f = m f υ and g V = m V υ plot measured g f vs m f gv measured υ vs m V and 3 ATLASCMS SM Higgs boson µ [M, ε] fit 68% CL 95% CL Particle mass [GeV] all scale like m as expected, over υ more than 3 orders of magnitude! Standard Model works pretty well M. Fanti (Physics Dep., UniMi) Higgs boson properties / 8

21 Testing decays to BSM particles ln Λ ATLAS and CMS [κ Z, κ W, κ t, κ τ, κ b, κ g, κ γ, B ] BSM LHC Run Observed SM expected A branching ratio to BSM particles B BSM is allowed as a free parameter 5 3 upper limit at 95% C.L. : B BSM <.3 (expected: B BSM <.39) B BSM M. Fanti (Physics Dep., UniMi) Higgs boson properties / 8

22 Couplings at 3 TeV [CMS-PAS-HIG6-], [ATLAS-CONF-6-79] H γγ channel H l channel κ f CMS H γγ m H Profiled Best Fit σ σ SM Preliminary.9 fb ( κ V TeV) 8 6 q(κ V,κ f ) κ g CMS Preliminary.9 fb (3 H γγ m H Profiled Best Fit κ γ σ σ SM TeV) 8 6 q(κ γ,κ g ) κ F ATLAS Preliminary H ZZ* l 3 TeV,.8 fb m H = 5.9 GeV Best fit 68% CL 95% CL SM.5.5 κ V M. Fanti (Physics Dep., UniMi) Higgs boson properties / 8

23 tth production [ATLAS-CONF-6-68, ATLAS-CONF-6-8, ATLAS-CONF-6-58], [HIG6-] tth(h γγ) (3 TeV 3.3 fb tth(h WW/ττ/ZZ) (3 TeV 3. fb ) tth(h bb) (3 TeV 3. fb ) ) ATLAS Preliminary total stat. s=3 TeV, fb ( tot. ) ( stat., syst. ) (, ) (, ) (, ) important to probe directly the tth Yukawa coupling cross-section 3 TeV wrt 8 TeV tth combination (3 TeV) tth combination ( 7-8TeV,.5-.3 fb ) (, ) (, ) 6 8 best fit µ for m H =5 GeV tth [CMS, 3 TeV,.9 fb ] Significance wrt no-signal hypothesis: 3. σ (CMS),.8 σ (ATLAS) M. Fanti (Physics Dep., UniMi) Higgs boson properties 3 / 8

24 Search for H b b [ CMS-PAS-HIG6-3 ], [ JHEP(5)69, ATLAS-CONF-6-9 ] CMS: 8 TeV ATLAS: (VH production) ATLAS Ldt=.7 fb ; Ldt=.3 fb s=7 TeV, s=8 TeV, tot. stat. tot ( stat syst ) ZH (..7 )..5 CMS: 3 TeV (VBF production) WH (.5. ) ln L CMS Preliminary 9.8 fb (8TeV).3 fb (3TeV) 95% CL VBF H bb 8TeV Observed 8TeV Expected 3TeV Observed 3TeV Expected 8TeV 3TeV Observed 8TeV 3TeV Expected Combination ATLAS (.3.5 ) Preliminary Tot. Stat. best fit µ=σ/σ for m H =5 GeV SM s=3 TeV, L dt= 3. fb Tot. ( Stat. Syst. ) 3 ZH (.9.5 ).7. 68% CL µ WH Combination (..5.5 ( ) ) Best fit µ=σ/σ for m H =5 GeV SM M. Fanti (Physics Dep., UniMi) Higgs boson properties / 8

25 Spin hypothesis test and parity measurements ATLAS: [ Eur. Phys. J. C75 (5) 76 ], CMS: [ PRD 9 (5) ] M. Fanti (Physics Dep., UniMi) Higgs boson properties 5 / 8

26 Spin/parity measurement H γγ: flat cos θ for spin-, sensitive to spin-...8 spin kq = kg kq = kq = kg H ZZ l: cosθ* H WW lνlν: W /W spin correlation spin l ν Arbitrary Normalisation.3. ATLAS Simulation, Preliminary s = 8 TeV (*) H WW eµ/µe jets H H [5] [5]. l H mw W W m ν H ν m W m l Arbitrary Normalisation. 3 ATLAS Simulation, Preliminary s = 8 TeV (*) H WW eµ/µe jets H H [5] [5] φ(ll) 5 angular observables m, m 3 can probe polarization of both H and Zs sensitive to spin and parity ν l. sensitive to spin and parity 6 8 m ll [GeV] M. Fanti (Physics Dep., UniMi) Higgs boson properties 6 / 8

27 Spin- tests effective lagrangian [HiggsCharacterization] effective transition amplitude [JHU] [ below, q ln ( LJ P L ) ] Arbitrary normalisation ATLAS Data SM (κ q =κ g ) H ZZ* l s = 7 TeV,.5 fb s = 8 TeV,.3 fb H WW* eνµν s = 8 TeV,.3 fb H γγ s = 7 TeV,.5 fb s = 8 TeV,.3 fb ~ q / L ) P ln(l - J CMS X ZZ WW 9.7 fb (8 TeV) 5. fb (7 TeV) - Observed Expected ± σ P J ± σ ± σ P J ± σ ± 3σ P J ± 3σ m h h3 h b h6 - h - h9 - h h7 m h h3 h b h6 h7 - h - h9 - h qq gg production qq production data favour spin- M. Fanti (Physics Dep., UniMi) Higgs boson properties 7 / 8

28 Parity and CP-mixing L V = X {cos α κ SM [ g HZZZ µ Z µ g HWW W µ W µ ] [ ] cos α κ HZZ Z µν Z µν µν sin α κ AZZ Z µν Z Λ [cos α κ HWW W Λ µνw µν sin α κ AWW W µν W ] } µν Standard Model : α =, κ HVV =, κ AVV = Beyond SM : κ HVV CP-even, κ AVV CP-odd CP-mixing for α and α π - ln λ ATLAS Observed Expected: signal strength fit to data Expected: SM H ZZ* l s = 7 TeV,.5 fb s = 8 TeV,.3 fb - ln λ ATLAS Observed Expected: signal strength fit to data Expected: SM H ZZ* l s = 7 TeV,.5 fb s = 8 TeV,.3 fb κ HVV = υ Λ κ HVV κ AVV = υ Λ κ AVV κ 8 /κ HVV SM ( κ 6 8 /κ ) tan α AVV SM κ HVV, κ AVV compatible with M. Fanti (Physics Dep., UniMi) Higgs boson properties 8 / 8

29 CP-tests at 3 TeV [ATLAS-CONF-6-79] ln(l) ATLAS Preliminary H ZZ* l 3 TeV,.8 fb Observed Expected ln(l) ATLAS Preliminary H ZZ* l 3 TeV,.8 fb Observed Expected % CL 6 95% CL Some tension for κ HVV,.σ... not worrisome at this stage, though 68% CL κ HVV 68% CL 5 5 κ AVV *sin(α) M. Fanti (Physics Dep., UniMi) Higgs boson properties 9 / 8

30 Width measurement M. Fanti (Physics Dep., UniMi) Higgs boson properties 3 / 8

31 Width measurement [Phys. Lett. B 736 () 6] In Standard Model, the Higgs decay width is expected to be Γ H MeV cannot measure it from the observed resonance width (experimental uncertainty O (GeV)) Use H ZZ ( ) l decays. Compare Higgs on-shell (gg H ZZ ) and off-shell (gg H ZZ) production cross-sections: σ gg H ZZ g Hgg g HZZ ; σ gg H Γ H m ZZ g Hgg g HZZ H (m Z ) under specific assumptions on how g Hgg, g HZZ scale with ŝ, σ gg H ZZ σ gg H ZZ Events / GeV CMS 9.7 fb (8 TeV) 5. fb (7 TeV) Events / 3 GeV Data ggvv ZZ qq ZZ ZX kin D bkg > m l (GeV) m l (GeV) gives a measurement of Γ H M. Fanti (Physics Dep., UniMi) Higgs boson properties 3 / 8

32 Total width at 8 and 3 TeV [ Phys. Lett. B 736 () 6, CMS-PAS-HIG6-33 ] 8 TeV 3 TeV - lnl 8 CMS 9.7 fb (8 TeV) 5. fb (7 TeV) l observed l expected lν l observed on-shell lν l expected on-shell Combined ZZ observed Combined ZZ expected - lnl 6 CMS Preliminary.9 fb (3 TeV) 5 GeV < m l < 6 GeV Observed Expected 6 H ZZ 8 95% CL 6 68% CL 95% CL 68% CL Γ H (MeV) Γ H [GeV] Γ H < MeV (at 95% CL) Γ H < MeV (at 95% CL) M. Fanti (Physics Dep., UniMi) Higgs boson properties 3 / 8

33 Differential cross-sections M. Fanti (Physics Dep., UniMi) Higgs boson properties 33 / 8

34 Differential Run-I [ EPJC 76 (6) 3, JHEP (6) 5, HIG5- ], [ Phys. Rev. Lett. 5 (5) 98, arxiv:6.997 ] CMS: H γγ, H l, H WW eνµν [fb/gev] γγ dσ/dp T CMS Data σ SM (H γγ) from LHC Higgs XS WG AMC@NLO XH HRES XH POWHEG XH -5 - POWHEG XH, FW =5E GeV -5 - POWHEG XH, FW=-5E GeV XH = VBFVHttH 9.7fb (8TeV) >GeV) T σ(p (H) [fb/gev] T - CMS Data (stat. sys. unc.) Systematic uncertainty Model dependence 9.7 fb (8 TeV) gg H (POWHEGJHUGen) XH gg H (MiNLO HJ) XH gg H (HRes) XH XH = VBF VH tth dσ fid /dp [fb/gev] CMS.8.6 H T Data Statistical uncertainty Systematic uncertainty Model dependence ggh (POWHEGVJHUGen) XH ggh (HRes) XH XH = VBF VH 9. fb (8 TeV) - dσ fid /dp -3.. Ratio to POWHEGXH γγ p [GeV] T Ratio to HRes p (H) [GeV] T ATLAS: H γγ, H l combined, H WW eνµν Ratio to HResXH p H [GeV] T dσ / dp [pb/gev] H T HRES XH XH = VBF VH tth bbh data, tot. unc. s = 8 TeV,.3 fb ATLAS pp H syst. unc. /dp [fb/gev] dσ fid H T ATLAS data, tot. unc. gg H sys. unc. σ LHC-XS σ LHC-XS σ LHC-XS s = 8 TeV,.3 fb H WW* eνµν A NNLOPSPY8 A MG5_aMC@NLOPY8 A SHERPA.. Ratio to HRes ph T [GeV] Ratio to NNLOPS 3 [,] [,6] [6,3] M. Fanti (Physics Dep., UniMi) Higgs boson properties 3 / 8 ph T [GeV]

35 Differential cross-sections at 3 TeV H ZZ l H γγ dσ fid /dp γγ [fb/gev] T.5 ATLAS Preliminary data, tot. unc. syst. unc. H γ γ, s = 3 TeV, 3.3 fb m H = 5.9 GeV gg H NNLOPS XH =. k gg H XH = VBF VH tth.5 data / prediction p γγ T M. Fanti (Physics Dep., UniMi) Higgs boson properties 35 / 8

36 Conclusions M. Fanti (Physics Dep., UniMi) Higgs boson properties 36 / 8

37 Conclusions Run-I analyses well mature, ATLASCMS combined results available for mass and couplings: v V m κ V or v F m κ F 3 ATLAS and CMS LHC Run µ b τ t W Z ATLASCMS SM Higgs boson [M, ε] fit 68% CL 95% CL Particle mass [GeV] κ g ATLAS and CMS LHC Run ATLASCMS ATLAS CMS 68% CL 95% CL Best fit SM expected κ γ Arbitrary normalisation ATLAS Data SM (κ q=κ g) H ZZ* l s = 7 TeV,.5 fb s = 8 TeV,.3 fb H WW* eνµν s = 8 TeV,.3 fb H γγ s = 7 TeV,.5 fb s = 8 TeV,.3 fb ~ q - lnl 8 6 CMS 9.7 fb (8 TeV) 5. fb (7 TeV) l observed l expected lν l observed on-shell lν l expected on-shell Combined ZZ observed Combined ZZ expected H ZZ 95% CL 68% CL Γ H (MeV) Run-II: efficient data-taking, analyses progressing fast, (cross-section) (luminosity) already beated Run-I [pb] σ pp H 8 6 ATLAS Preliminary σ pp H m H = 5.9 GeV H γ γ H ZZ * l comb. data syst. unc. QCD scale uncertainty Tot. uncert. (scale PDFα s ) tth(h γγ) (3 TeV 3.3 fb ) tth(h WW/ττ/ZZ) (3 TeV 3. fb tth(h bb) (3 TeV 3. fb ) ) ATLAS Preliminary total stat. s=3 TeV, fb ( tot. ) ( stat., syst. ) (, ).3..5 (, ) (, ) κ f CMS Preliminary H γγ m H Profiled Best Fit σ σ SM.9 fb (3 TeV) 8 6 q(κ V,κ f ) κ g CMS Preliminary fb (3 H γγ m H Profiled Best Fit σ σ SM TeV) 8 6 q(κ γ,κ g ) s = 7 TeV,.5 fb s = 8 TeV,.3 fb s = 3 TeV, 3.3 fb (γ γ ),.8 fb (ZZ *) s [TeV] tth combination (3 TeV) tth combination ( 7-8TeV,.5-.3 fb ) (, ) (, ) 6 8 best fit µ for m H =5 GeV tth κ V κ γ We are still compatible with Standard Model prediction... but uncertainties are still large. Theory uncertainties improved a lot. Important to pursue precision measurements in the Higgs sector, in Run-II and beyond, to investigate possible deviations from SM M. Fanti (Physics Dep., UniMi) Higgs boson properties 37 / 8

38 Thanks for your attention M. Fanti (Physics Dep., UniMi) Higgs boson properties 38 / 8

39 More material M. Fanti (Physics Dep., UniMi) Higgs boson properties 39 / 8

40 Statistical models used in measurements Extended likelihood function: L( α; ν): ln L( α; ν) = (n s n b ) signal pdf background pdf {}}{{}}{ n s f s ( x e α, ν s ) n b f b ( x e ν b ) e ancillary pdfs {}}{ ln π k (ν k ) k n s, n b : signal / background yields x: observables f s, f b : signal / background pdfs α: parameters of interest (mass, cross-section, couplings,... ) ν: nuisance parameters (shape parameters, systematics,... ) π k : pdfs obtained from auxiliary measurements Test statistic: Profiled Likelihood Ratio (PLR) q α = ln Λ( α) = ln L( α; ˆν( α)) L(ˆα; ˆν) L( α; ˆν( α)): likelihood for fixed α and profiled ν L(ˆα; ˆν): maximum likelihood for free α, ν Wilks theorem : if α = α true, then q α follows a χ D distribution, with D being the number of parameters of interest α ln Λ % CL α 68% CL ln Λ <.3 95% CL ln Λ < 6. compute confidence intervals for α 68% CL α α M. Fanti (Physics Dep., UniMi) Higgs boson properties / 8

41 Higgs observation in Run-I : H γγ and H ZZ l Events / GeV 5 L dt =.5 fb, s = 7 TeV L dt =.3 fb Unweighted sum, s = 8 TeV ATLAS Data Signalbackground Background 3 Signal H γγ data - fitted bkg m γγ [GeV] CMS s = 7 TeV, L = 5. fb ; s = 8 TeV, L = 9.7 fb Events/5 GeV Data SM Higgs Boson m H =.3 GeV (fit) Background Z, ZZ* Background Zjets, tt Syst.Unc. ATLAS H ZZ* l s = 7 TeV Ldt =.6 fb s = 8 TeV Ldt =.7 fb Events / 3 GeV 35 Data 3 5 ZX * Zγ,ZZ m H =6 GeV H l m l [GeV] (GeV) m l M. Fanti (Physics Dep., UniMi) Higgs boson properties / 8

42 Higgs candidates : H γγ and H ZZ ` H ZZ e e µµ candidate at ATLAS H γγ candidate at CMS M. Fanti (Physics Dep., UniMi) Higgs boson properties / 8

43 Mass measurement Use the H γγ and H ZZ l decay channels that allow a full kinematics reconstruction with good invariant mass resolution (O ( GeV)) l channel ) ln Λ(m H ATLAS and CMS LHC Run H ZZ l ATLAS CMS Combined Stat. only uncert. γγ channel ) ln Λ(m H ATLAS and CMS LHC Run H γ γ ATLAS CMS Combined Stat. only uncert [GeV] ˆm l H = 5.5 ±.37(stat) ±.5(syst) GeV Good signal/background, low statistics e, µ energy scales from J/ψ, Υ, Z ll m H ˆm γγ H [GeV] m H = 5.7 ±.5(stat) ±.(syst) GeV Large background, good statistics γ energy scale from Z e e and e γ extrapolation M. Fanti (Physics Dep., UniMi) Higgs boson properties 3 / 8

44 Comparison with SM expectations Compatibility with the SM prediction of fit results as a whole under the asymptotic approximation. For each parameterisation, the unconditional best fit is compared with the conditional fit where all parameters are set to their SM values. The conversion from ln Λ to the quoted p-value is performed assuming a two-sided distribution with the specified number of degrees of freedom (DOF). The quoted p-values are partially correlated between the different parameterisations. M. Fanti (Physics Dep., UniMi) Higgs boson properties / 8

45 Extraction of signal yield per category... Events / GeV data - b ATLAS data sb fit background, b pp H γ γ, s = 8 TeV L dt =.3 fb = 5. GeV m H jet N jets =, p > 3 GeV T m γ γ [GeV] divide events in categories (e.g. number of jets, bins of p γγ T, bins of Y γγ, etc... ) from the invariant mass spectrum, extract the signal yield in each category / bin Events / GeV 8 6 ATLAS pp H γ γ, s = 8 TeV L dt =.3 fb = 5. GeV m H jet N jets =, p > 3 GeV T data sb fit background, b data - b m γγ [GeV] m γ γ [GeV] Events / GeV ATLAS pp H γ γ, s = 8 TeV L dt =.3 fb = 5. GeV m H jet N jets =, p > 3 GeV T data - b data sb fit background, b m γγ [GeV] m γ γ [GeV] Events / GeV 8 6 ATLAS pp H γ γ, s = 8 TeV L dt =.3 fb = 5. GeV m H jet N jets 3, p > 3 GeV T data - b - data sb fit background, b m γγ [GeV] m γ γ [GeV] then unfold the experimental effects (efficiencies, migrations,... ) get the cross-section per category / bin M. Fanti (Physics Dep., UniMi) Higgs boson properties 5 / 8

46 Differential cross-sections H γγ [fb/gev] / dp dσ fid T ATLAS data syst. unc. gg H (HRES) X H =.5) (K ggf X H = VBF VH tth H γ γ, s = 8 TeV L dt =.3 fb / d y [fb] dσ fid 6 ATLAS data syst. unc. H γ γ, s = 8 TeV gg H (HRES) X H 5 (K ggf =.5) L dt =.3 fb 3 X H = VBF VH tth [fb] σ fid ATLAS data syst. unc. gg H (MiNLO HJPY8) X H =.5) (K ggf X H = VBF VH tth H γ γ, s = 8 TeV L dt =.3 fb jet p > 3 GeV T data / prediction γ γ p [GeV] T data / prediction y γ γ data / prediction 5 3 N jets H ZZ l [fb/gev] T / dp dσ fid ATLAS.6 data syst. unc. H ZZ* l gg H (MiNLO HJPS) X H s = 8 TeV L dt =.3 fb gg H (POWHEGPS) X H gg H (HRES) X H X H = VBF VH tth / d y [fb] dσ fid ATLAS 3.5 data syst. unc. H ZZ* l gg H (MiNLO HJPS) X H 3 s = 8 TeV L dt =.3 fb gg H (POWHEGPS) X H gg H (HRES) X H X H = VBF VH tth [fb] σ fid.8 ATLAS data syst. unc. H ZZ* l.6 gg H (MiNLO HJPS) X H s = 8 TeV L dt =.3 fb. gg H (POWHEGPS) X H jet p > 3 GeV T X H = VBF VH tth p T,H [GeV] y H 3 n jets N jets M. Fanti (Physics Dep., UniMi) Higgs boson properties 6 / 8

47 tth production [HIG5-8, HIG6-, HIG5-5] - ln L m H = 5 GeV CMS Preliminary.95 Observed:.5.8 Expected: fb (3 TeV) tth combination HIG5-5 H γγ HIG5-8 H leptons HIG6- H bb tth 95% CL upper limit on µ m H = 5 GeV CMS Preliminary tth production limits Observed Expected ±σ Expected ±σ Expected.3-.7 fb (3 TeV) 6 3 µ tth Combined H leptons HIG5-8 [to be updated if new results arrive from CMS 6 data] H bb HIG6- H γγ HIG5-5 M. Fanti (Physics Dep., UniMi) Higgs boson properties 7 / 8

48 f f Total cross-section from γγ and l final states [ATLAS-CONF-6-8] [pb] σ pp H ATLAS Preliminary σ pp H m H = 5.9 GeV γ γ 8 H H ZZ * l comb. data syst. unc. QCD scale uncertainty Tot. uncert. (scale PDFα s ) SM [pb] (σ B) /B VBF ATLAS Preliminary s=3 TeV, 3.3 fb (γγ),.8 fb (ZZ) = 5.9 GeV m H SM Best fit 68% CL 95% CL H γγ H ZZ* l s [TeV] s = 7 TeV,.5 fb s = 8 TeV,.3 fb s = 3 TeV, 3.3 fb (γ γ ),.8 fb (ZZ *) 6 8 (σ B) / B f ggf f SM [pb] M. Fanti (Physics Dep., UniMi) Higgs boson properties 8 / 8

Measurements of the Higgs Boson Couplings and Other Properties at the LHC

Measurements of the Higgs Boson Couplings and Other Properties at the LHC Marcello Fanti (on behalf of the ATLAS and CMS collaborations) University of Milano and INFN M. Fanti (Physics Dep., UniMi) Higgs