Higgs boson couplings characterization in the 4-lepton channel with the Run 2 data of the ATLAS Experiment at the LHC

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Higgs boson couplings characterization in the 4-lepton channel with the Run 2 data of the ATLAS Experiment at the LHC 36 th IMPRS Workshop at Max Planck

1 Higgs boson couplings characterization in the 4-lepton channel with the Run 2 data of the ATLAS Experiment at the LHC 36 th IMPRS Workshop at Max Planck Institute of Physics Simona Gargiulo - Sapienza, Università di Roma - INFN November 7, 26 Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 / 28

2 Table of contents What s next after the Higgs boson discovery? 2 An effective field theory for the Higgs characterization 3 H ZZ 4l channel 4 The ATLAS detector at the LHC 5 Method to discriminate possible BSM effects 6 Conclusions and plans Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 2 / 28

3 What s next after the Higgs boson discovery? Outline What s next after the Higgs boson discovery? 2 An effective field theory for the Higgs characterization 3 H ZZ 4l channel 4 The ATLAS detector at the LHC 5 Method to discriminate possible BSM effects 6 Conclusions and plans Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 3 / 28

4 What s next after the Higgs boson discovery? Higgs boson discovery from both ATLAS and CMS experiments 2 exclusion of spin and 2 hypotheses with the Run data 3 search for a discrepancy in the size and structure of the Higgs boson couplings with respect to the SM predictions 4 assuming v, the vacuum expectation value, the expected values of the Higgs couplings with the vector bosons V and fermions f are: g HVV = 2m2 V v, g Hff = m f v Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 4 / 28

5 An effective field theory for the Higgs characterization Outline What s next after the Higgs boson discovery? 2 An effective field theory for the Higgs characterization 3 H ZZ 4l channel 4 The ATLAS detector at the LHC 5 Method to discriminate possible BSM effects 6 Conclusions and plans Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 5 / 28

6 An effective field theory for the Higgs characterization The Lagrangian of interaction of a bosonic state X(J P ) with spin/parity assignments +, with vector bosons can be written as follows []: Assumption: k HZZ = k HWW = k HVV and k AZZ = k AWW = k AVV Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 6 / 28

7 An effective field theory for the Higgs characterization The Lagrangian of interaction of a bosonic state X(J P ) with spin/parity assignments +, with vector bosons can be written as follows []: Assumption: k HZZ = k HWW = k HVV and k AZZ = k AWW = k AVV Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 6 / 28

8 An effective field theory for the Higgs characterization The Lagrangian of interaction of a bosonic state X(J P ) with spin/parity assignments +, with vector bosons can be written as follows []: Assumption: k HZZ = k HWW = k HVV and k AZZ = k AWW = k AVV Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 6 / 28

9 An effective field theory for the Higgs characterization The Lagrangian of interaction of a bosonic state X(J P ) with spin/parity assignments +, with vector bosons can be written as follows []: Assumption: k HZZ = k HWW = k HVV and k AZZ = k AWW = k AVV Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 6 / 28

10 H ZZ 4l channel Outline What s next after the Higgs boson discovery? 2 An effective field theory for the Higgs characterization 3 H ZZ 4l channel 4 The ATLAS detector at the LHC 5 Method to discriminate possible BSM effects 6 Conclusions and plans Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 7 / 28

11 H ZZ 4l channel H ZZ 4l channel BR(H ZZ 4l) =.25 4 at m H = 25 GeV N exp events = σ SMBRL int 694 with L int = fb at s = 3 TeV clean signature given by the presence of leptons (e and µ) in the final state single and dilepton trigger on e and µ Higgs boson candidate: quadruplet of two same-flavour, opposite-sign lepton pairs leptons in the quadruplet ordered in p T : p T > 2 GeV, > 5 GeV, > GeV, > 6 GeV (µ) and > 7 GeV (e) main backgrounds: irreducible pp ZZ 4l, reducible Z+jets, t t Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 8 / 28

12 H ZZ 4l channel Event candidates divided into three experimental categories: jet, jet, 2jets VBF hadronic VH ggf jet jet jets Table: Yields of VBF, hadronic VH and ggf in each category, for L int = 4.8 fb and s = 3 TeV and after the event selection. 2jets category divided into two categories with a cut on the reconstructed invariant mass of the two jets M reco jj : if Mjj reco if Mjj reco 2 GeV: VBF-category < 2 GeV: VH-category Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 9 / 28

13 The ATLAS detector at the LHC Outline What s next after the Higgs boson discovery? 2 An effective field theory for the Higgs characterization 3 H ZZ 4l channel 4 The ATLAS detector at the LHC 5 Method to discriminate possible BSM effects 6 Conclusions and plans Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 / 28

argon detector with accordion geometry 4 Hadronic calorimeter: iron as absorber and scintillating materials 5 Muon spectrometer:

14 The ATLAS detector at the LHC Magnetic system: one barrel and two end-cap toroids, central solenoid (2 T) 2 Inner detector: silicon pixels, semiconductor tracker (SCT) and transition radiation tracker (TRT) 3 Electromagnetic calorimeter: lead-liquid argon detector with accordion geometry 4 Hadronic calorimeter: iron as absorber and scintillating materials 5 Muon spectrometer: muon chambers with high resolution and standalone muons reconstruction Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 / 28

15 Method to discriminate possible BSM effects Outline What s next after the Higgs boson discovery? 2 An effective field theory for the Higgs characterization 3 H ZZ 4l channel 4 The ATLAS detector at the LHC 5 Method to discriminate possible BSM effects 6 Conclusions and plans Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 2 / 28

16 Method to discriminate possible BSM effects New physics effects on the signal strength [2] SM σ/σ σ vs k 6 bsm /σ SM Hvv SM σ VH /σ VH SM σ VBF /σ VBF SM σ ggf /σ ggf SM σ/σ SM σ VH /σ VH SM σ VBF /σ VBF SM σ ggf /σ ggf vs k Avv σ bsm /σ SM k Avv VBF and VH mechanisms have a greater sensitivity to the BSM couplings The ggf mechanism depends only marginally from the BSM couplings The SM and BSM contributions interfere when µ = σbsm is a function of σ SM k HVV. The interference is greater in the case of VH and has an opposite sign compared to that of VBF No interference expected when the cross section is a function of k AVV Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 3 / 28

17 Method to discriminate possible BSM effects New physics effects on the shape of kinematic differential distributions of signal and backgrounds Other discriminating variables Events Events VBF VH ggf ZZ, Z+jets k SM =, k Hvv = m 2 [GeV] VBF VH ggf ZZ, Z+jets k SM =, k Hvv = m 34 [GeV] Events VBF + VH ggf ZZ, Z+jets k SM =, k Hvv = M jj Need a multivariate analysis to combine the shape of many kinematic distributions. Matrix element based observables Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 4 / 28

18 Method to discriminate possible BSM effects Definition of the matrix element of a process BSM coupling entering in production or decay vertex (ggf) s M(k SM, k BSM ) = k SM M SM + k BSM M BSM () use of 4 leptons to build the matrix element BSM coupling entering in both production and decay vertices (VBF and VH) M(k SM, k BSM ) = (k SM M SM,p + k BSM M BSM,p ) (k SM M SM,d + k BSM M BSM,d ). (2) use of 4 leptons and 2 jets to build the matrix element Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 5 / 28

19 Method to discriminate possible BSM effects Optimal Observables (OO) for VBF and VH [3] OO = Interference M SM 2 OO 2 = M BSM 2 M SM 2 M(k SM, k BSM ) 2 = ksm 4 M SM,p 2 M SM,d 2 + kbsm 4 M BSM,p 2 M BSM,d 2 + [ + ksm 3 k BSM M SM,p 2 R( M SM,d M BSM,d )+ + R( M SM,p M BSM,p ) M SM,d 2] + + ksm 2 k2 BSM ( M SM,p 2 M BSM,d 2 + M BSM,p 2 M SM,d 2 )+ [ + kbsm 3 k SM M BSM,p 2 R( M SM,d M BSM,d )+ + R( M SM,p M BSM,p ) M BSM,d 2] I considered as Interference all the terms that are highlighted in red: Interference = M(k SM, k BSM ) 2 k 4 SM M SM,p 2 M SM,d 2 k 4 BSM M BSM,p 2 M BSM,d 2 k 2 SM k2 BSM ( M SM,p 2 M BSM,d 2 + M BSM,p 2 M SM,d 2 ) M BSM can be M khvv or M kavv define four optimal observables: OO H, OOH 2, OOA, OOA 2. Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 6 / 28

20 Method to discriminate possible BSM effects M SM M khvv M kavv Λ = 3 GeV; k SM = ; all BSM couplings k BSM = ; Λ = 3 GeV; k SM = ; k HVV = ; all other BSM couplings k BSM = ; Λ = 3 GeV; k SM = ; k AVV = 5; all other BSM couplings k BSM = ; s Each matrix element should be created for both VBF and VH mechanisms. VBF MadGraph [2] NLO process p p j j x, x z z e+ e- mu+ mu- 6 particles in the final state: 2 jets and 4 leptons jetp T > 3 GeV VH MadGraph NLO process p p v x, v j j, x z z e+ e- mu+ mu- 6 particles in the final state: 2 jets and 4 leptons jetp T > 3 GeV Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 7 / 28

21 Method to discriminate possible BSM effects OO distributions for the VBF-category OO OO 2 OO for the VH-category Events k SM =, k Hvv k SM =, k Hvv = = VBF: Optimal Observable Interference OO Events.4 k SM =, k = Hvv k SM =, k = Hvv VBF: Optimal Observable 2order OO 2 Events.4 k SM =, k = Avv.35 k SM =, k = 5 Avv VBF: Optimal Observable Interference OO Events.4 k SM =, k = Avv.35 k SM =, k = 5.3 Avv These distributions are made using full simulation samples. Backup slides for those made using MadGraph samples VBF: Optimal Observable 2order OO 2 Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 8 / 28

22 Method to discriminate possible BSM effects OO distributions for the VBF-category with 4.8 fb of data Events Data k SM =, k Hvv k SM =, k Hvv ZZ, Z+jets ggf tt = = ATLAS Work in Progress s = 3 TeV VBF: OO_kHvv - Ldt = 4.8 fb Events Data k SM =, k Hvv k SM =, k Hvv ZZ, Z+jets ggf tt = = ATLAS Work in Progress s = 3 TeV VBF: OO2_kHvv - Ldt = 4.8 fb OO OO 2 Events Data k SM =, k Avv k SM =, k Avv ZZ, Z+jets ggf tt = = 5 ATLAS Work in Progress s = 3 TeV VBF: OO_kAvv5 - Ldt = 4.8 fb Events Data k SM =, k Avv k SM =, k Avv ZZ, Z+jets ggf tt = = 5 ATLAS Work in Progress s = 3 TeV VBF: OO2_kAvv5 - Ldt = 4.8 fb OO OO 2 Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 9 / 28

23 Method to discriminate possible BSM effects Estimation of expected OO sensistivity Use the binned OO distributions calculate the Poisson probability to obtain the number of events relative to a certain BSM coupling k test, n injected i (k test ), if one expects a number n expected i (k BSM ) k SM = in the fit ggf and backgrounds included but considered independent from the BSM coupling N bin L(k BSM ) = i= Poisson(n injected i (k test ), n expected i (k BSM )) n expected i (k BSM ), obtained using the morphing technique [4] n injected i (k test ), yield of the i th bin of the injected histogram relative to k test ; N bin, total number of bins of the histograms. Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 2 / 28

24 Method to discriminate possible BSM effects Fit to = using OO H (L = 4.8 fb ) Fit to k HVV = using OO H VBF OO: vs khvv..8 VBF OO: vs khvv VH OO: vs khvv..8.6 VH OO: vs khvv Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 2 / 28

25 Method to discriminate possible BSM effects Fit to = using OO H (L = 4.8 fb ) Fits using MadGraph samples 2 8 Sum OO: vs khvv..8 Sum OO: vs khvv Optimal observables Cross section alone Observable k HVV Observable k HVV OO H [-5.2, 4.] OO H (single bin) [-6., 4.7] Table: Expected 95% confidence intervals on k HVV for OO H between the VBF and VH loglikelihoods. and for the sum Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 22 / 28

26 Method to discriminate possible BSM effects Fit to k Avv = using OO A (L = 4.8 fb ) Fit to k AVV = using OO A VBF OO: vs kavv VBF OO: vs kavv k Avv k Avv VH OO: vs kavv VH OO: vs kavv k Avv k Avv Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 23 / 28

27 Method to discriminate possible BSM effects Fit to k AVV = using OO A (L = 4.8 fb ) Sum OO: vs kavv Sum OO: vs kavv k Avv k Avv Optimal observables Cross section alone Observable k AVV Observable k AVV OO A [-5., 5.] OO A (single bin) [-5.8, 5.8] Table: Expected 95% confidence intervals on k AVV for OO A between the VBF and VH loglikelihoods. and for the sum Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 24 / 28

28 Method to discriminate possible BSM effects Fit to k HVV = 2.5 and k HVV = 5 using OO H (L = 4.8 fb ) Other fit closure tests Sum OO: vs khvv Sum OO: vs khvv Sum OO: vs khvv Sum OO: vs khvv Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 25 / 28

29 Conclusions and plans Outline What s next after the Higgs boson discovery? 2 An effective field theory for the Higgs characterization 3 H ZZ 4l channel 4 The ATLAS detector at the LHC 5 Method to discriminate possible BSM effects 6 Conclusions and plans Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 26 / 28

30 Conclusions and plans Conclusions and plans Conclusions: Plans: The use of matrix element based observables enables to increase the sensitivity to the BSM couplings with respect to the one obtained using the cross section alone; with higher statistics, order of fb, it will be possible to further improve the expected 95% confidence levels on the BSM couplings 2. slides. addition of the jet category; exploit the OO to do a fit without fixing k SM = and discriminate between k HVV and k AVV ; 2 The performances of this analysis on a dataset of 3 fb can be found in the backup Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 27 / 28

31 Conclusions and plans Bibliografy P. Artoisenet, P. de Aquino, F. Demartin, R. Frederix, S.Frixione, F. Maltoni, M. K. Mandal, P. Mathews, K. Mawatari, V. Ravindran, S. Seth, P. Torrielli, M. Zaro, A framework for the Higgs characterisation, (2 Jan 24) arxiv: [hep-ph]. J. Alwall, R. Frederix, S. Frixione, V. Hirschi, F. Maltoni, O. Mattelaer, H.-S. Shao, T. Stelzer, P. Torrielli, M. Zaro, The automated computation of tree-level and next-to-leading order differential cross sections, and their matching to parton shower simulations, arxiv:45.3v2 [hep-ph]. OPAL Technical note, Dave Charleton, Alun Llyod, Measurement of Triple Gauge Coupling Parameters with Optimal Observables for W + W l + νl ν Events at s = 89 GeV, arxiv:hep-ph/29229v. ATLAS NOTE A morphing technique for signal modelling in a multidimensional space of coupling parameters, ATL-PHYS-PUB Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 28 / 28

32 Outline 7 Backup slides Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 29 / 28

33 Evidence for the spin- nature of the Higgs boson ) P alt ( J CL s ATLAS H γγ s = 8 TeV Ldt = 2.7 fb H ZZ* 4l - s = 7 TeV Ldt = 4.6 fb s = 8 TeV Ldt = 2.7 fb H WW* eνµν/µνeν - s = 8 TeV Ldt = 2.7 fb - - Data CL s expected P assuming J = ± σ + σ 2σ 3σ σ -6 P - J = P + J = P - P + J = J = 2 m Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 3 / 28

34 Event selection criteria H ZZ 4l p T, E T and η cuts Electrons: E T > 7 GeV, η < 2.47 Combined, standalone and segment-tagged muons: p T > 5 GeV Calo-tagged muons: p T > 5 GeV, η <. Jets: p T > 3 GeV Leptons in the quadruplets First lepton: p T > 2 GeV Second lepton: p T > 5 GeV Third lepton: p T > GeV Maximum one calo-tagged or standalone muon per quadruplet Leading dilepton mass: 5 < m 2 < 6 GeV Sub-leading dilepton mass: 2 < m 34 < 5 GeV Isolation Electron track isolation ( R.2): E T /E T <.5 Electron calorimetric isolation ( R.2): E T /E T <.2 Muon track isolation ( R.3): p T /p T <.5 Muon calorimetric isolation ( R.2): E T /p T <.3 Impact parameter significance Electrons: d /σ d < 5 Muons: d /σ d < 3 Leptons: (z z pv )sinθ <.5 mm Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 3 / 28

35 Leptons and jets discriminating variables Experimental categories Events Events VBF VH ggf ZZ, Z+jets k SM =, k Hvv = leading jet p [GeV] T.4 VBF VH ggf.2 ZZ, Z+jets k SM =, k Hvv = subleading jet p [GeV] T Events Events VBF VH ggf ZZ, Z+jets k SM =, k Hvv = η leading jet VBF VH ggf ZZ, Z+jets k SM =, k Hvv = η subleading jet Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 32 / 28

36 Events.3 VBF VH ggf.25 ZZ, Z+jets k SM =, k Hvv.2 = Events.3 VBF VH ggf.25 ZZ, Z+jets k SM =, k Hvv.2 = cosθ cosθ 2 Events VBF VH ggf ZZ, Z+jets k SM =, k Hvv = φ Events.22 VBF VH ggf ZZ, Z+jets k SM =, k Hvv = φ Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 33 / 28

37 Definition of interference between SM and BSM matrix elements OO definition One non-sm coupling in the production or decay vertex M(k SM, k BSM ) = k SM M SM + k BSM M BSM Squaring this expression, one obtains: M(k SM, k BSM ) 2 = ksm M 2 SM 2 + kbsm M 2 BSM 2 + 2k SM k BSM R(M SMM BSM ) Therefore, the interference in the case of the ggf production mode is given by: Interference = 2R(M SMM BSM ) = ( = M(k SM, k BSM ) 2 k k SM k SM M 2 SM 2 kbsm M 2 BSM 2) BSM Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 34 / 28

38 Definition of interference between SM and BSM matrix elements OO definition One non-sm coupling in both production and decay M(k SM, k BSM ) = (k SM M SM,p + k BSM M BSM,p ) (k SM M SM,d + k BSM M BSM,d ). Squaring this expression, one obtains: M(k SM, k BSM ) 2 = ksm 4 M SM,p 2 M SM,d 2 + kbsm 4 M BSM,p 2 M BSM,d 2 + [ + ksm 3 k BSM M SM,p 2 R( M SM,d M BSM,d )+ + R( M SM,p M BSM,p ) M SM,d 2] + + ksm 2 k2 BSM ( M SM,p 2 M BSM,d 2 + M BSM,p 2 M SM,d 2 )+ [ + kbsm 3 k SM M BSM,p 2 R( M SM,d M BSM,d )+ + R( M SM,p M BSM,p ) M BSM,d 2] One can call Interference all the terms that are highlighted in red: Interference = M(k SM, k BSM ) 2 k 4 SM M SM,p 2 M SM,d 2 k 4 BSM M BSM,p 2 M BSM,d 2 k 2 SM k2 BSM ( M SM,p 2 M BSM,d 2 + M BSM,p 2 M SM,d 2 ) Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 35 / 28

39 Backup slides ME distributions on VBF MadGraph samples Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 36 / 28

40 ME distributions using events of the VBF-category Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 37 / 28

41 OO distributions for the VH-category OO OO for the VBF-category OO 2 Events.5.4 k SM =, k = Hvv k SM =, k = Hvv VH: Optimal Observable Interference Events.5.4 k SM =, k = Hvv k SM =, k = Hvv VH: Optimal Observable 2order OO OO 2 Events.5.4 k SM =, k = Avv k SM =, k = 5 Avv VH: Optimal Observable Interference Events k SM =, k = Avv k SM =, k = 5 Avv VH: Optimal Observable 2order OO OO 2 These distributions are made using full simulation samples. Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 38 / 28

42 VBF OO distributions using MadGraph samples OO distributions OO OO 2 Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 39 / 28

43 Implementation of the morphing technique Morphing method The morphing method can be introduce to describe the dependence of a given observable T on an arbitrary set of non-sm Higgs boson couplings ktarget = k SM, k BSM,,..., k BSM,n to known particles. This dependence is describes by a morphing function: T out ( k target ) = i w i ( k target ; k i )T in ( k i ), where T in are values or differential distributions obtained from Monte Carlo simulation of the signal for a given coupling configuration k i. T in are normalised to their expected cross sections such that the physical observable T out includes both the correct shape and the correct cross section prediction. Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 4 / 28

44 Morphing with one non-sm coupling parameter in the production or decay vertex Morphing method The simpler case is that of the ggf process in which the k BSM coupling with W and Z enters only in decay. As T (k SM, k BSM ) M(k SM, k BSM ) 2, one can write the input distributions for arbitrary input parameters k i : T in (k SM,i, k BSM,i ) = k 2 SM,i M 2 SM +k 2 BSM,i M 2 BSM +2k SM,i k BSM,i R(M SMM BSM ) where i =, 2, 3. T out (k SM, k BSM ) = (a k 2 SM + a 2 k 2 BSM + a 3 k SM k BSM )T in (k SM,, k BSM, ) + = + (a 2 k 2 SM + a 22 k 2 BSM + a 23 k SM k BSM )T in (k SM,2, k BSM,2 ) + = + (a 3 k 2 SM + a 32 k 2 BSM + a 33 k SM k BSM )T in (k SM,3, k BSM,3 ) Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 4 / 28

45 Morphing with one non-sm coupling parameter in the production or decay vertex Morphing method To find the unknown variables a ij one can observe that if: ktarget = k i T out = T in This suggests that a ij coefficients can be found by solving the following condition: a a 2 a 3 ksm, 2 ksm,2 2 k 2 SM,3 a 2 a 22 a 23 kbsm, 2 kbsm,2 2 k 2 BSM,3 = I a 3 a 32 a 33 k SM, k BSM, k SM, k BSM, k SM, k BSM, This procedure should be repeated also for the VBF process for which the number of T in input distributions will be 5. Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 42 / 28

46 Morphing validation: VBF-category Not base Base Events Original Histo: SM Morphed Histo: k Hvv = Morphed Histo VBF OO Not base Events Original Histo: k Hvv Morphed Histo: k Hvv = 5 = 5 Morphed Histo VBF OO Events Original Histo: SM Morphed Histo VBF Morphed Histo: k Hvv OO 2 Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 43 / 28 =

47 Morphing validation: VH-category Not base Base Events Original Histo: SM Morphed Histo: k Hvv = Morphed Histo VH OO Not base Events Original Histo: k Hvv Morphed Histo: k Hvv = 5 = 5 Morphed Histo VH OO Events Morphed Histo VH Original Histo: SM Morphed Histo: k Avv = OO 2 Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 44 / 28

48 Fit to = using OO H 2 (L = 4.8 fb ) Fit to k HVV = using OO H VBF OO2: vs khvv..8 VBF OO2: vs khvv VH OO2: vs khvv..8 VH OO2: vs khvv Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 45 / 28

49 Fit to = using OO H 2 (L = 4.8 fb ) 2 8 Sum OO2: vs khvv..8 Sum OO2: vs khvv Optimal observables Cross section alone Observable k HVV Observable k HVV OO H 2 [-5.2, 4.2] OO H 2 (single bin) [-6., 4.7] Table: Expected 95% confidence intervals on k HVV for OO2 H between the VBF and VH loglikelihoods. and for the sum Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 46 / 28

50 Fit to k Avv = using OO A 2 (L = 4.8 fb ) Fit to k AVV = using OO A VBF OO2: vs kavv VBF OO2: vs kavv k Avv k Avv VH OO2: vs kavv VH OO2: vs kavv k Avv k Avv Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 47 / 28

51 Fit to k Avv = using OO A 2 (L = 4.8 fb ) Sum OO2: vs kavv Sum OO2: vs kavv k Avv k Avv Optimal observables Cross section alone Observable k AVV Observable k AVV OO A 2 [-5., 5.] OO A 2 (single bin) [-5.8, 5.8] Table: Expected 95% confidence intervals on k AVV for OO2 A between the VBF and VH loglikelihoods. and for the sum Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 48 / 28

52 Fit closure tests using MadGraph samples Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 49 / 28

53 Fit to = on a VBF sample (L = 4.8 fb ) OO OO 2 Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 5 / 28

54 Fit to k Avv = on a VBF sample (L = 4.8 fb ) Fits on full sim samples OO OO 2 Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 5 / 28

55 Other fit closure tests using full simulation samples Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 52 / 28

56 Fit to = 2.5 using OO H (L = 4.8 fb ) VBF OO: vs khvv VBF OO: vs khvv VH OO: vs khvv VH OO: vs khvv Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 53 / 28

57 Fit to = 2.5 using OO H (L = 4.8 fb ) Sum OO: vs khvv Sum OO: vs khvv Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 54 / 28

58 Fit to = 2.5 using OO H 2 (L = 4.8 fb ) VBF OO2: vs khvv VBF OO2: vs khvv VH OO2: vs khvv VH OO2: vs khvv Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 55 / 28

59 Fit to = 2.5 using OO H 2 (L = 4.8 fb ) 8 6 Sum OO2: vs khvv Sum OO2: vs khvv Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 56 / 28

60 Fit to k Avv = 2.5 using OO A (L = 4.8 fb ) VBF OO: vs kavv VBF OO: vs kavv k Avv k Avv VH OO: vs kavv VH OO: vs kavv k Avv k Avv Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 57 / 28

61 Fit to k Avv = 2.5 using OO A (L = 4.8 fb ) Sum OO: vs kavv Sum OO: vs kavv k Avv k Avv Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 58 / 28

62 Fit to k Avv = 2.5 using OO A 2 (L = 4.8 fb ) VBF OO2: vs kavv VBF OO2: vs kavv k Avv k Avv VH OO2: vs kavv VH OO2: vs kavv k Avv k Avv Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 59 / 28

63 Fit to k Avv = 2.5 using OO A 2 (L = 4.8 fb ) Sum OO2: vs kavv Sum OO2: vs kavv k Avv k Avv Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 6 / 28

64 Fit to = 5 using OO H (L = 4.8 fb ) 5 4 VBF OO: vs khvv 4 2 VBF OO: vs khvv VH OO: vs khvv VH OO: vs khvv Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 6 / 28

65 Fit to = 5 using OO H (L = 4.8 fb ) Sum OO: vs khvv Sum OO: vs khvv Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 62 / 28

66 Fit to = 5 using OO H 2 (L = 4.8 fb ) VBF OO2: vs khvv VBF OO2: vs khvv VH OO2: vs khvv 4 2 VH OO2: vs khvv Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 63 / 28

67 Fit to = 5 using OO H 2 (L = 4.8 fb ) Sum OO2: vs khvv Sum OO2: vs khvv Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 64 / 28

68 Fit to k Avv = 5 using OO A (L = 4.8 fb ) VBF OO: vs kavv VBF OO: vs kavv k Avv k Avv 2 8 VH OO: vs kavv VH OO: vs kavv k Avv k Avv Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 65 / 28

69 Fit to k Avv = 5 using OO A (L = 4.8 fb ) Sum OO: vs kavv Sum OO: vs kavv 5 5 k Avv k Avv Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 66 / 28

70 Fit to k Avv = 5 using OO A 2 (L = 4.8 fb ) VBF OO2: vs kavv VBF OO2: vs kavv k Avv k Avv 8 VH OO2: vs kavv VH OO2: vs kavv k Avv k Avv Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 67 / 28

71 Fit to k Avv = 5 using OO A 2 (L = 4.8 fb ) Sum OO2: vs kavv Sum OO2: vs kavv k Avv k Avv Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 68 / 28

72 OO distributions for the 4.8 fb dataset Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 69 / 28

73 OO distributions for the VH-category Events Data k SM =, k Hvv k SM =, k Hvv ZZ, Z+jets ggf tt = = ATLAS Work in Progress s = 3 TeV - Ldt = 4.8 fb OO VH: OO_kHvv Events Data k SM =, k Hvv k SM =, k Hvv ZZ, Z+jets ggf tt = = ATLAS Work in Progress s = 3 TeV - Ldt = 4.8 fb OO 2 VH: OO2_kHvv Events Data k SM =, k Avv k SM =, k Avv ZZ, Z+jets ggf tt = = 5 ATLAS Work in Progress s = 3 TeV VH: OO_kAvv5 - Ldt = 4.8 fb Events Data k SM =, k Avv k SM =, k Avv ZZ, Z+jets ggf tt = = 5 ATLAS Work in Progress s = 3 TeV VH: OO2_kAvv5 - Ldt = 4.8 fb OO OO 2 Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 7 / 28

74 Observed 95% exclusion ranges with 4.8 fb Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 7 / 28

75 Backup slides Fit to khvv = using OOH Simona Gargiulo (L = 4.8 fb ) Higgs boson couplings with W ± and Z 7//26 72 / 28

76 Fit to k HVV = using OO H (L = 4.8 fb ) Optimal observables Cross section alone Observable k HVV Observable k HVV OO H [-, -.3], [.4, 6.3] OO H (single bin) [-2, -3.], [2., 6.8] Table: Observed 95% confidence intervals on k HVV for OO H between the VBF and VH loglikelihoods. and for the sum Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 73 / 28

77 Backup slides Fit to khvv = using OO2H Simona Gargiulo (L = 4.8 fb ) Higgs boson couplings with W ± and Z 7//26 74 / 28

78 Fit to k HVV = using OO H 2 (L = 4.8 fb ) Optimal observables Cross section alone Observable k HVV Observable k HVV OO H 2 [-8.8, 6,] OO H 2 (single bin) [-2, -3.], [2., 6.8] Table: Observed 95% confidence intervals on k HVV for OO2 H between the VBF and VH loglikelihoods. and for the sum Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 75 / 28

79 Backup slides Fit to kavv = using OOA Simona Gargiulo (L = 4.8 fb ) Higgs boson couplings with W ± and Z 7//26 76 / 28

80 Fit to k AVV = using OO A (L = 4.8 fb ) Optimal observables Cross section alone Observable k AVV Observable k AVV OO A [-8.,6.6] OO A (single bin) [-8.6, -2.3], [2.2, 9.] Table: Observed 95% confidence intervals on k AVV for OO A between the VBF and VH loglikelihoods. and for the sum Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 77 / 28

81 Backup slides Fit to kavv = using OO2A Simona Gargiulo (L = 4.8 fb ) Higgs boson couplings with W ± and Z 7//26 78 / 28

82 Fit to k AVV = using OO A 2 (L = 4.8 fb ) Optimal observables Cross section alone Observable k AVV Observable k AVV OO A 2 [-8., -.5], [.5, 8.] OO A 2 Table: Observed 95% confidence intervals on k AVV for OO2 A between the VBF and VH loglikelihoods. (single bin) [-8.6, -2.3], [2.2, 9.] and for the sum Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 79 / 28

83 Prospects with 3 fb of data: a look at HL-LHC Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 8 / 28

84 Fit to = using OO H (L = 3 fb ) VBF OO: vs khvv VH OO: vs khvv Sum OO: vs khvv Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 8 / 28

85 Fit to = using OO H 2 (L = 3 fb ) VBF OO2: vs khvv VH OO2: vs khvv Sum OO2: vs khvv Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 82 / 28

86 Fit to k Avv = using OO A (L = 3 fb ) VBF OO: vs kavv VH OO: vs kavv k Avv k Avv Sum OO: vs kavv k Avv Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 83 / 28

87 Fit to k Avv = using OO A 2 (L = 3 fb ) VBF OO2: vs kavv VH OO2: vs kavv k Avv k Avv Sum OO2: vs kavv k Avv Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 84 / 28

88 Results with 4.8 fb Table: Expected 95% confidence intervals on k HVV and k AVV for the sum between the VBF and VH loglikelihoods. These intervals have been obtained for L int = 3 fb. OO H OO2 H OO A OO2 A Optimal observables Observable k HVV k AVV OO H [-.7,.7] - OO2 H [-.7,.8] - OO A - [-2., 2.] OO2 A - [-2., 2.] Cross section alone Observable k HVV k AVV (single bin) [-2., 2.] - (single bin) [-2., 2.] - (single bin) - [-2.5, 2.6] (single bin) - [-2.5, 2.6] Simona Gargiulo Higgs boson couplings with W ± and Z 7//26 85 / 28

Higgs cross-sections

Higgs cross-sections Ph.D. Detailed Research Project Search for a Standard Model Higgs boson in the H ZZ ( ) 4l decay channel at the ATLAS Experiment at Cern Ph.D. Candidate: Giacomo Artoni Supervisor: Prof. Carlo Dionisi,