Discovery of the Higgs boson. and most recent measurements at the LHC

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1 Discovery of the Higgs boson and most recent measurements at the LHC Marcello Fanti (on behalf of the ATLAS-Mi group) University of Milano and INFN M. Fanti (Physics Dep., UniMi) title in footer / 35

2 July 4th, 0 the discovery! we have a discovery ATLAS and CMS observed a new signal : incompatibility with background-only hypothesis was 5σ (CMS) and 6σ (ATLAS) M. Fanti (Physics Dep., UniMi) title in footer / 35

3 July 4th, 0 the discovery! we have a discovery What is this? Is it indeed the Higgs boson?... and if so, why is it so important? M. Fanti (Physics Dep., UniMi) title in footer / 35

4 Symmetries, gauge theories (just a glance... ) All interactions (strong, electroweak) are driven by symmetry principles: strong interaction color symmetry electroweak interaction isospin symmetry very predictive, only few assumptions u d ν e All interactions are reducible to combinations of few elementary processes: renormalizable at all perturbative orders, UV-safe, all desirable theory properties... M. Fanti (Physics Dep., UniMi) title in footer 3 / 35

5 Symmetries, gauge theories (just a glance... ) All interactions (strong, electroweak) are driven by symmetry principles: strong interaction color symmetry electroweak interaction isospin symmetry very predictive, only few assumptions u d ν e All interactions are reducible to combinations of few elementary processes: renormalizable at all perturbative orders, UV-safe, all desirable theory properties... BUT: all this works only if all masses are = 0 masses break gauge symmetries! M. Fanti (Physics Dep., UniMi) title in footer 3 / 35

6 The Higgs mechanism and the Higgs boson A new quantum field φ, with charge = 0 and spin = 0, is postulated, whose potential U(φ) has a minimum at φ 0 the vacuum is characterized by a non-vanishing field, interacting with other particles M. Fanti (Physics Dep., UniMi) title in footer 4 / 35

7 The Higgs mechanism and the Higgs boson A new quantum field φ, with charge = 0 and spin = 0, is postulated, whose potential U(φ) has a minimum at φ 0 the vacuum is characterized by a non-vanishing field, interacting with other particles Such interactions modify particles energies and momenta such to provide a mass (recall: m = E p ) particles acquire mass dynamically (gauge symmetry is preserved!) particles can excite the Higgs field, thus producing an observable quantum: the Higgs particle M. Fanti (Physics Dep., UniMi) title in footer 4 / 35

8 The Higgs mechanism and the Higgs boson A new quantum field φ, with charge = 0 and spin = 0, is postulated, whose potential U(φ) has a minimum at φ 0 the vacuum is characterized by a non-vanishing field, interacting with other particles Such interactions modify particles energies and momenta such to provide a mass (recall: m = E p ) particles acquire mass dynamically (gauge symmetry is preserved!) particles can excite the Higgs field, thus producing an observable quantum: the Higgs particle The observation of such a particle is the experimental proof of the Higgs mechanism M. Fanti (Physics Dep., UniMi) title in footer 4 / 35

9 Observation of the Higgs boson M. Fanti (Physics Dep., UniMi) title in footer 5 / 35

10 The LHC Located near Geneva, 7 km long, 0 m underground Proton beams accelerated to 6.5 TeV colliding at 3 TeV 4 protons / beam ( protons / bunch) ] 45 Delivered Luminosity [fb ATLAS Online Luminosity 0 pp s = 7 TeV 0 pp s = 8 TeV 05 pp s = 3 TeV 06 pp s = 3 TeV 07 pp s = 3 TeV initial 07 calibration bunches collide every 5 ns 40 millions collisions/s Peak luminosity 34 cm s 5 0 Jan Apr Jul Oct Month in Year M. Fanti (Physics Dep., UniMi) title in footer 6 / 35

11 The LHC ] 45 Delivered Luminosity [fb ATLAS Online Luminosity 0 pp s = 7 TeV 0 pp s = 8 TeV 05 pp s = 3 TeV 06 pp s = 3 TeV 07 pp s = 3 TeV initial 07 calibration 5 0 Jan Apr Jul Oct Month in Year M. Fanti (Physics Dep., UniMi) title in footer 6 / 35

12 ATLAS and CMS ATLAS CMS M. Fanti (Physics Dep., UniMi) title in footer 7 / 35

13 ATLAS and CMS ATLAS CMS Characteristics multi-purpose experiments, made of several nested detectors full solid angle coverage, high granularity (millions of electronics channels) fast data acquisition (every 5 ns) high radiation hardness M. Fanti (Physics Dep., UniMi) title in footer 7 / 35

14 ATLAS and CMS ATLAS CMS Characteristics multi-purpose experiments, made of several nested detectors full solid angle coverage, high granularity (millions of electronics channels) fast data acquisition (every 5 ns) high radiation hardness A little of history conceived in 99, approved in 995 construction started in 997 tests of prototypes at test beams: assembly and installation: tests with cosmic rays: start of operation at LHC: end 009 M. Fanti (Physics Dep., UniMi) title in footer 7 / 35

15 Identifying particles Only few particles are stable, or quasi-stable : e ±, γ, π ±, p, p, n, n, K 0 L, µ± (i.e. living long enough to cross the full detector) M. Fanti (Physics Dep., UniMi) title in footer 8 / 35

16 Identifying particles Only few particles are stable, or quasi-stable : e ±, γ, π ±, p, p, n, n, K 0 L, µ± (i.e. living long enough to cross the full detector) Most heavy particles decay quickly to lighter ones: need to identify decay products and infer the original particle M. Fanti (Physics Dep., UniMi) title in footer 8 / 35

17 Typical events at LHC Proton beams collide every 5 ns: up to 50 proton-proton interactions hundreds of particles are produced p p M. Fanti (Physics Dep., UniMi) title in footer 9 / 35

18 Typical events at LHC Proton beams collide every 5 ns: up to 50 proton-proton interactions hundreds of particles are produced p p ZZ e e µ µ M. Fanti (Physics Dep., UniMi) title in footer 9 / 35

19 Typical events at LHC Proton beams collide every 5 ns: up to 50 proton-proton interactions hundreds of particles are produced p p ZZ e e µ µ multi-jet event M. Fanti (Physics Dep., UniMi) title in footer 9 / 35

20 Typical events at LHC Proton beams collide every 5 ns: up to 50 proton-proton interactions hundreds of particles are produced p p ZZ e e µ µ multi-jet event A tiny fraction of such events ( in billions) is a Higgs boson M. Fanti (Physics Dep., UniMi) title in footer 9 / 35

21 How to observe the Higgs boson: decay modes Higgs BR Total Uncert [%] ττ cc bb γγ gg Zγ WW ZZ LHC HIGGS XS WG 03 3 µµ M H [GeV] M. Fanti (Physics Dep., UniMi) title in footer / 35

22 How to observe the Higgs boson: decay modes Higgs BR Total Uncert [%] ττ cc bb γγ gg Zγ WW ZZ LHC HIGGS XS WG 03 Most common decay modes ( H b b, H τ τ ) are very difficult, due to large hadronic background. 3 µµ M H [GeV] M. Fanti (Physics Dep., UniMi) title in footer / 35

23 How to observe the Higgs boson: decay modes Higgs BR Total Uncert [%] 3 ττ cc µµ bb γγ gg Zγ WW ZZ LHC HIGGS XS WG 03 Most common decay modes ( H b b, H τ τ ) are very difficult, due to large hadronic background. More suitable are: H BR pros/cons γγ 0.00 good mass resolution, S/B 0.0 ZZ 4l good mass resolution, S/B WW lνlν cannot measure mass M H [GeV] M. Fanti (Physics Dep., UniMi) title in footer / 35

24 Best discovery channels H γγ candidate at CMS H ZZ e e µ µ candidate at ATLAS Fully reconstructed final states with good energy resolution M. Fanti (Physics Dep., UniMi) title in footer / 35

25 Invariant mass plots Events / GeV L dt = 4.5 fb, s = 7 TeV L dt = 0.3 fb Unweighted sum, s = 8 TeV ATLAS Data Signalbackground H γγ decay channel 3000 Background Signal m γγ = (E γ E γ ) p γ p γ (m γγ peaks at m H if γγ are from Higgs) data - fitted bkg m γγ [GeV] CMS s = 7 TeV, L = 5. fb ; s = 8 TeV, L = 9.7 fb H 4l decay channel ( 4 ) m 4l = E l l= 4 p l l= (m 4l peaks at m H if 4l are from Higgs) Events/5 GeV Data 0 0 SM Higgs Boson m H =4.3 GeV (fit) Background Z, ZZ* Background Zjets, tt Syst.Unc. ATLAS H ZZ* 4l s = 7 TeV Ldt = 4.6 fb s = 8 TeV Ldt = 0.7 fb m 4l [GeV] Events / 3 GeV 35 Data ZX * Zγ,ZZ m H =6 GeV (GeV) m 4l M. Fanti (Physics Dep., UniMi) title in footer / 35

26 The Higgs mass ATLAS and CMS Run Total Stat. Syst. LHC Total Stat. Syst. ATLAS H γ γ 6.0 ± 0.5 ( ± 0.43 ± 0.7) GeV CMS H γ γ 4.70 ± 0.34 ( ± 0.3 ± 0.5) GeV ATLAS H ZZ 4l 4.5 ± 0.5 ( ± 0.5 ± 0.04) GeV CMS H ZZ 4l 5.59 ± 0.45 ( ± 0.4 ± 0.7) GeV ATLAS CMS γ γ 5.07 ± 0.9 ( ± 0.5 ± 0.4) GeV ATLAS CMS 4l 5.5 ± 0.40 ( ± 0.37 ± 0.5) GeV ATLAS CMS γ γ 4l 5.09 ± 0.4 ( ± 0. ± 0.) GeV m H [GeV] M. Fanti (Physics Dep., UniMi) title in footer 3 / 35

27 The Higgs mass ATLAS and CMS Run Total Stat. Syst. LHC Total Stat. Syst. ATLAS H γ γ 6.0 ± 0.5 ( ± 0.43 ± 0.7) GeV CMS H γ γ 4.70 ± 0.34 ( ± 0.3 ± 0.5) GeV ATLAS H ZZ 4l 4.5 ± 0.5 ( ± 0.5 ± 0.04) GeV CMS H ZZ 4l 5.59 ± 0.45 ( ± 0.4 ± 0.7) GeV ATLAS CMS γ γ 5.07 ± 0.9 ( ± 0.5 ± 0.4) GeV ATLAS CMS 4l 5.5 ± 0.40 ( ± 0.37 ± 0.5) GeV Once m H is measured, all other properties can be predicted can test the Higgs sector ATLAS CMS γ γ 4l 5.09 ± 0.4 ( ± 0. ± 0.) GeV m H [GeV] cross-section decay width branching ratios σ(pp HX) [pb] pp HX at s=4 TeV pp HX at s=8 TeV LHC HIGGS XS WG 0 Γ H [GeV] 3 LHC HIGGS XS WG 0 Higgs BR Total Uncert ττ cc bb gg WW ZZ tt LHC HIGGS XS WG 0 pp HX at s=7 TeV γγ Zγ M H [GeV] M H [GeV] M H [GeV] M. Fanti (Physics Dep., UniMi) title in footer 3 / 35

28 Properties of the Higgs boson M. Fanti (Physics Dep., UniMi) title in footer 4 / 35

29 Cross-section measurements Total cross-section vs s (γγ and 4l combined) [pb] σ pp H 0 ATLAS Preliminary σ pp H m H = 5.09 GeV 80 H γ γ H ZZ * 4l comb. data syst. unc. QCD scale uncertainty Tot. uncert. (scale PDFα s ) s = 7 TeV, 4.5 fb s = 8 TeV, 0.3 fb s = 3 TeV, 3.3 fb (γ γ ), 4.8 fb (ZZ *) s [TeV] M. Fanti (Physics Dep., UniMi) title in footer 5 / 35

30 Higgs production modes at the 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 4FS) pp tth (NLO QCD NLO EW) pp th (NLO QCD, t-ch s-ch) LHC HIGGS XS WG 06 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) title in footer 6 / 35

31 Couplings measurements According to SM, the Higgs couplings are g SM f = m f υ and g SM V = m V υ i o H SM κ i g i κ o g o SM Couplings are accessible through production (ii H) and decay (H oo) i o Several couplings: g µ, g τ, g b, g W, g Z, g t g H W H W gluons and photons are massless no direct ggh, Hγγ couplings g t, b H H t gg H through top/bottom virtual loop mainly driven by g t, g b H γγ through top/bottom and W virtual loops mainly driven by g W, g t, g b M. Fanti (Physics Dep., UniMi) title in footer 7 / 35

32 Couplings measurements According to SM, the Higgs couplings are g SM f = m f υ and g SM V = m V υ v V m κ V ATLAS and CMS LHC Run W Z t decay measure plot v F m κ F or fermions g f g f τ b bosons g V gv υ 3 4 ATLASCMS SM Higgs boson µ [M, ε] fit 68% CL 95% CL Particle mass [GeV] all scale like m υ as expected, over > 3 orders of magnitude! distinctive signature of the Higgs mechanism! M. Fanti (Physics Dep., UniMi) title in footer 7 / 35

33 Spin H γγ: H WW lνlν: l ν l H mw W W m ν H ν m W m l H ZZ 4l: ν l Spin can be probed from angular distributions of decay products M. Fanti (Physics Dep., UniMi) title in footer 8 / 35

34 Spin H γγ: H WW lνlν: l ν l H mw W W m ν H ν m W m l ν l Observation of H γγ decay excludes spin H ZZ 4l: test spin-0 against spin- M. Fanti (Physics Dep., UniMi) title in footer 8 / 35

35 Spin H γγ: H WW lνlν: ν l H mw l W W m ν H ν l m W m l ν Use likelihood-ratio test statistic ( ) L(spin-0) q ln L(spin-) Arbitrary normalisation 3 ATLAS Data 0 SM (κ q =κ g ) H ZZ* 4l s = 7 TeV, 4.5 fb s = 8 TeV, 0.3 fb H WW* eνµν s = 8 TeV, 0.3 fb H γγ s = 7 TeV, 4.5 fb s = 8 TeV, 0.3 fb H ZZ 4l: ~ q M. Fanti (Physics Dep., UniMi) title in footer 8 / 35

36 Spin H γγ: H WW lνlν: ν l H mw l W W m ν H ν l m W m l ν Use likelihood-ratio test statistic ( ) L(spin-0) q ln L(spin-) Arbitrary normalisation 3 ATLAS Data 0 SM (κ q =κ g ) H ZZ* 4l s = 7 TeV, 4.5 fb s = 8 TeV, 0.3 fb H WW* eνµν s = 8 TeV, 0.3 fb H γγ s = 7 TeV, 4.5 fb s = 8 TeV, 0.3 fb H ZZ 4l: ~ q data favour spin-0 M. Fanti (Physics Dep., UniMi) title in footer 8 / 35

37 Summary M. Fanti (Physics Dep., UniMi) title in footer 9 / 35

38 Present measurements The Higgs boson was discovered, now we are in the middle of the Higgs measurements era. [pb] σ pp H ATLAS Preliminary σ pp H m H = 5.09 GeV H γ γ H ZZ * 4l comb. data syst. unc. QCD scale uncertainty Tot. uncert. (scale PDFα s ) s [TeV] s = 7 TeV, 4.5 fb s = 8 TeV, 0.3 fb s = 3 TeV, 3.3 fb (γ γ ), 4.8 fb (ZZ *) v V m κ V or v F m κ F 3 4 ATLAS and CMS LHC Run µ τ b W Z ATLASCMS SM Higgs boson [M, ε] fit 68% CL 95% CL Particle mass [GeV] t Arbitrary normalisation ATLAS Data 0 SM (κ q =κ g ) H ZZ* 4l s = 7 TeV, 4.5 fb s = 8 TeV, 0.3 fb H WW* eνµν s = 8 TeV, 0.3 fb H γγ s = 7 TeV, 4.5 fb s = 8 TeV, 0.3 fb ~ q We are still compatible with Standard Model prediction... but uncertainties are still large. Meanwhile, huge effort from theorists to improve their uncertainties [see talk by G.Ferrera]. Important to pursue precision measurements in the Higgs sector, to investigate possible deviations from SM M. Fanti (Physics Dep., UniMi) title in footer 0 / 35

39 Prospects... Results: ATLASCMS, 8 TeV Expected: 3 TeV, 300 fb and 3000 fb (ATLAS only) v V m κ V or v F m κ F 3 4 ATLAS and CMS LHC Run µ τ b W Z ATLASCMS SM Higgs boson [M, ε] fit 68% CL 95% CL t i y Ratio to SM ATLAS Simulation Preliminary h γγ, h ZZ* 4l, h WW* lνlν h ττ, h bb, h µµ, h Zγ [κ Z, κ W, κ t, κ b, κ τ, κ µ ] BR i,u =0 µ τ b s = 4 TeV W Ldt = 300 fb Z Ldt = 3000 fb t Particle mass [GeV] [GeV] m i Some educated guesses With 300 fb at 3 TeV: Precise measurements of H τ τ, observation of H b b, evidence of t th production Evidence of H µ µ, precision measurements of all individual κ s to % accuracy M. Fanti (Physics Dep., UniMi) title in footer / 35

40 Milano s involvement M. Fanti (Physics Dep., UniMi) title in footer / 35

41 Milano s involvements Detector Detector construction pixel detector (innermost tracking device) electromagnetic calorimeter magnets for muon chambers M. Fanti (Physics Dep., UniMi) title in footer 3 / 35

42 Milano s involvements Detector Detector construction pixel detector (innermost tracking device) electromagnetic calorimeter magnets for muon chambers R & D Electronics: upgrade for high-luminosity phase [talk by A.Stabile] Pixel detector: L.Rossini] radiation damage studies [poster by M. Fanti (Physics Dep., UniMi) title in footer 3 / 35

43 Milano s involvements Detector In Higgs analyses Detector construction pixel detector (innermost tracking device) electromagnetic calorimeter magnets for muon chambers R & D Electronics: upgrade for high-luminosity phase [talk by A.Stabile] Pixel detector: L.Rossini] radiation damage studies [poster by H γγ: photon energy calibration photon identification and background treatment m H and couplings measurement spin measurement H τ τ : measurement of the missing transverse momentum (recall, τ decays to ν τ (invisible!) other particles) τ reconstruction CP measurement [poster by A.Murrone] M. Fanti (Physics Dep., UniMi) title in footer 3 / 35

44 Milano s involvements Detector In Higgs analyses Detector construction pixel detector (innermost tracking device) electromagnetic calorimeter magnets for muon chambers R & D Electronics: upgrade for high-luminosity phase [talk by A.Stabile] Pixel detector: L.Rossini] radiation damage studies [poster by H γγ: photon energy calibration photon identification and background treatment m H and couplings measurement spin measurement H τ τ : measurement of the missing transverse momentum (recall, τ decays to ν τ (invisible!) other particles) τ reconstruction CP measurement [poster by A.Murrone] More analyses in ATLAS where Milano is involved: searches for SUSY [poster by S.Carrà] other exotic searches, including Dark Matter [talk by D.D Angelo] M. Fanti (Physics Dep., UniMi) title in footer 3 / 35

45 THANKS FOR YOUR ATTENTION M. Fanti (Physics Dep., UniMi) title in footer 4 / 35

46 More Material M. Fanti (Physics Dep., UniMi) title in footer 5 / 35

47 Decay modes of the Higgs boson All hadronic decay modes (H b b and H ZZ, W W q qq q) are dominant, but overwhelmed by the QCD backgrounds! final states with isolated leptons, photons, missing transverse energy are the only viable Higgs BR Total Uncert [%] ττ cc bb γγ gg Zγ WW ZZ LHC HIGGS XS WG 03 BR [pb] σ - - τ τ VBF H τ τ ± WH l νbb - s = 8TeV ± WW l νqq - WW l νl ν - ZZ l l qq ZZ l l νν ZZ l l l l LHC HIGGS XS WG µµ M H [GeV] ZH l l bb l = e, µ ν = ν e,ν µ,ν τ q = udscb tth ttbb γγ M H [GeV] H BR σ BR (fb) events produced mass m H background (@ m H = 5 GeV) with 5 fb resolution range γγ GeV ZZ 4l GeV WW lνlν anywhere τ τ (VBF) GeV b b (VH, Z l l W lν) GeV M. Fanti (Physics Dep., UniMi) title in footer 6 / 35

48 Cross-section by CMS Fiducial cross-section vs s H 4l [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 =5.09 GeV) - norm. LHC Higgs XSWG YR4 - acc. AMC@NLO 9.7 fb (8 TeV).9 fb (3 TeV) pp (H 4l) X s (TeV) s (TeV) M. Fanti (Physics Dep., UniMi) title in footer 7 / 35

49 Couplings: the κ-framework Reminder: in SM Higgs couplings are g SM f = m f υ and g SM V = m V υ i H SM κ i g i κ o g o SM o Couplings are accessible through production (ii H) and decay (H oo) Define couplings modifiers κ x = g x gx SM (compatibility with SM κ ) i o Several couplings: κ µ, κ τ, κ b, κ W, κ Z, κ t and two effective couplings: κ g, κ γ g t, b H H W H W gg H (mainly) through top/bottom virtual loop κ g depends on κ t, κ b g H t H γγ through top/bottom and W virtual loops κ γ depends on κ t, κ b, κ W M. Fanti (Physics Dep., UniMi) title in footer 8 / 35

50 (Universal) couplings to fermions and weak bosons Assume weak gauge boson universality: κ W, κ Z = κ V and fermion universality: κ t, κ b, κ τ, κ µ = κ f 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 0.5 all measurements compatible with SM prediction ( ) (κ V =, κ f = ) 68% CL 95% CL Best fit SM expected κf V M. Fanti (Physics Dep., UniMi) title in footer 9 / 35

51 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.4. 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) title in footer 30 / 35

52 Couplings: the κ-framework Reminder: in SM Higgs couplings are g SM f = m f υ and g SM V = m V υ and σsm ii H oo Γ iiγ oo Γ H i i H SM κ i g i κ o g If no decays beyond Standard Model (BSM), Γ H = o SM o o Couplings are accessible through production (ii H) and decay (H oo) Define couplings modifiers κ x = g x g SM x o {SM} and κ H def = Γ H Γ SM H σ ii H oo = σ SM ii H oo κ i κ o Γ H oo = o {SM} Several couplings: κ µ, κ τ, κ b, κ W, κ Z, κ t and two effective couplings: κ g, κ γ κ H κ oγ SM H oo κ H = Assume weak gauge boson universality: κ W, κ Z = κ V and fermion universality: κ t, κ b, κ τ, κ µ = κ f o {SM} κ obr SM H oo g t, b H H W H W If loop-mediated interactions occur 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 0.6 κ t ) = (.6 κ V 0.6 κ f )... and κ H = 0.75 κ f 0.5 κ V computed using BR SM H m H = 5 GeV M. Fanti (Physics Dep., UniMi) title in footer 3 / 35

53 Spin H γγ: flat cos θ for spin-0, sensitive to spin spin kq = kg kq = 0 kq = kg H ZZ 4l: cosθ* H WW lνlν: W /W spin correlation spin 0 l ν Arbitrary Normalisation ATLAS Simulation, Preliminary s = 8 TeV (*) H WW eµ/µe 0 jets H 0 H [5] [5] 0. l H mw W W m ν H ν m W m l Arbitrary Normalisation ATLAS Simulation, Preliminary s = 8 TeV (*) H WW eµ/µe 0 jets H 0 H [5] [5] φ(ll) 5 angular observables m, m 34 can probe polarization of both H and Zs sensitive to spin and parity ν l 0. sensitive to spin and parity m ll [GeV] M. Fanti (Physics Dep., UniMi) title in footer 3 / 35

54 Spin- tests effective lagrangian [HiggsCharacterization] effective transition amplitude [JHU] [ below, q ln ( LJ P L 0 ) ] Arbitrary normalisation ATLAS Data 0 SM (κ q =κ g ) H ZZ* 4l s = 7 TeV, 4.5 fb s = 8 TeV, 0.3 fb H WW* eνµν s = 8 TeV, 0.3 fb H γγ s = 7 TeV, 4.5 fb s = 8 TeV, 0.3 fb ~ q / L 0 ) P ln(l - J CMS X ZZ WW 9.7 fb (8 TeV) 5. fb (7 TeV) - Observed Expected 0 ± σ P J ± σ 0 ± σ P J ± σ 0 ± 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-0 M. Fanti (Physics Dep., UniMi) title in footer 33 / 35

55 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 4 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 0 SM (κ q=κ g) H ZZ* 4l s = 7 TeV, 4.5 fb s = 8 TeV, 0.3 fb H WW* eνµν s = 8 TeV, 0.3 fb H γγ s = 7 TeV, 4.5 fb s = 8 TeV, 0.3 fb ~ q - lnl CMS 9.7 fb (8 TeV) 5. fb (7 TeV) 4l observed 4l expected lν 4l observed on-shell lν 4l 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 ATLAS Preliminary σ pp H m H = 5.09 GeV H γ γ H ZZ * 4l 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) q(κ V,κ f ) κ g CMS Preliminary fb (3 H γγ m H Profiled Best Fit σ σ SM TeV) q(κ γ,κ g ) 0 0 s = 7 TeV, 4.5 fb s = 8 TeV, 0.3 fb s = 3 TeV, 3.3 fb (γ γ ), 4.8 fb (ZZ *) s [TeV] tth combination (3 TeV) tth combination ( 7-8TeV, fb ) (, ) (, ) best fit µ for m H =5 GeV tth κ V κ γ 0 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) title in footer 34 / 35

56 Prospects... κ F fb, w/ theory 3000 fb, w/ theory fb, w/o theory 3000 fb, w/o theory Standard Model ATLAS Simulation Preliminary s = 4 TeV κ V i y Ratio to SM ATLAS Simulation Preliminary h γγ, h ZZ* 4l, h WW* lνlν h ττ, h bb, h µµ, h Zγ [κ Z, κ W, κ t, κ b, κ τ, κ µ ] BR i,u =0 µ τ b s = 4 TeV W Ldt = 300 fb Z Ldt = 3000 fb t [GeV] m i Some educated guesses With 300 fb at 3 TeV: Precise measurements of H τ τ, observation of H b b, evidence of t th production Evidence of H µ µ, precision measurements of all individual κ s to % accuracy M. Fanti (Physics Dep., UniMi) title in footer 35 / 35