HIGGS ISF HIGGS ISF HIGGS ISF HIGGS Eilam Gross, Weizmann Institute of Science 1 HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS Contributions to SM Higgs: E. Gozani, A. DiMattia, Y. Rozen (Technion), L.. Barak, M. Pitt, J. Schaarschmidt, E.G. (Weizmann) & E. Etzion (TAU) [for continuous support and encouragement in difficult time]

The discovery of the Higgs Boson (July 4 th 2012) occurred after we submitted the ISF proposal We now celebrate two years to Higgs discovery. This talk is about the distance we have all gone since the declaration of Higgs Hunters’ independence… Title of talk should be modified Searches  Precision measurements Mass Signal Strengths (cross section X BR) Couplings Off-shellness and width Rare decays HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS 2

3

4 ATLAS OLD

 Recalibration of Layers and gains  Muon momentum calibration  Electron and Photon energy calibration  Better and more accurate material description  Categories for mass in the diphoton  FSR recovery & corrections  BDT-ZZ & per event errors HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS 5 ID and Services Solenoid Cryostat PS Calorimeter L1 L2 L3 readout A. David ICHEP 2014

HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS 6 ATLAS OLD

HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS 7 ATLAS OLD

HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS 8 ATLAS NEW ATLAS NEW Submitted to PRD arXiv:

ATLAS CMS HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS 9

10

What do we measure We measure event yields We want to derive couplings and signal strengths The first thing we want to measure is the the “signal strength” per channel The analysis is using discriminators (usually reconstructed mass related) to increase S/B 11 HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS

What do we measure We measure event yields We want to derive couplings and signal strengths The first thing we want to measure is the the “signal strength” per channel The analysis is using discriminators (usually reconstructed mass related) to increase S/B 12 HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS

What do we measure We increase sensitivity by classifying the events via categories and measure the signal strength per category and then combining them taking all the sytematic and statistical uncertainties into account 13 Loose/tight high mass 2jet (VBF tag) Phys. Lett. B 726 (2013), pp The categories are also sensitive to different production modes, allowing the measurement of the couplings HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS ttH

Probe the Production Modes Define Parameterize with explicit production modes and decays Note: ONE CAN ONLY FIT THE PRODUCT We cannot fit simultaneously the cross section and the BR  No full Higgs width fit is possible to high accuracy at the LHC (from the signal rates) The categories allow us to fit specific production modes but no combination is possible unless we make assumptions on the BR 14 HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS CMS PAS HIG

Probing VBF production mode We fitted Taking one decay mode at a time we can go one step further and fit the ratio per channel 15 This ratio is INDEPENDENT of the decay channel so we can combine HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS ATLAS-CONF CMS PAS HIG

Probing VBF production mode We fitted Taking one decay mode at a time we can go one step further and fit the ratio per channel 16 This ratio is INDEPENDENT of the decay channel so we can combine ATLAS-CONF HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS

Evidence for VBF Higgs Production PROFILING we can Fit and find an evidence for VBF Higgs production 17 μ VBF =0 is excluded at 4.1σ (ATLAS) μ VBF =0 is excluded at 3.6σ (CMS) ATLAS-CONF HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS CMS PAS HIG

Indirect Sensitivity to Fermion Couplings Note that if all fermion couplings are set to be equal, 18 HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS

Direct observation of H  bb and H  The Bosonic channels (,ZZ,WW) provide indirect evidence about the fermion couplings to Higgs via loops But the direct evidence came with the observation of the bb and the by (first) CMS and (then) ATLAS 19 H->bb dominates the Higgs total width (BR~58%) ggF,H  bb is saturated with overwhelming direct production of bb from QCD background The handle is given by a Vector Boson produced in association with the H  bb in the VH,H  bb process. With a SM BR of over 6% and a relatively clean signal in VBF and Boosted categories, H  is even more important then the bb (with the current luminosity and analysis status) in order to establish the Higgs direct coupling to fermions. HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS

Fermions Direct: H  bb 20 arXiv: HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS

Fermions Direct: H  Discriminator is not necessarily mass 21 HH CMSATLAS Signal Strengthμ=0.78±0.27μ= Excess3.2σ (exp 3.7σ)4.1σ (exp 3.2σ) ATLAS-CONF arXiv: v1 [hep-ex]ATLAS-CONF HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS

ATLAS and CMS each sees a strong evidence for Higgs coupling to fermions with a strength consistent with the SM expectation When combined the significance observation goes beyond 5σ  ATLAS+CMS discovered H  Direct Evidence for H  Fermions Combining bb and 22 HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS

Comment: Fermions Direct: ttH Probing the Higgs Yukawa coupling to top is of an ultimate importance. m top /v ∼ 1. Higgs won’t decay to tt, but one can probe directly the ttH coupling by the Higgsstrahlung of Higgs off top or tt fusion to Higgs, or single top production. The Higgs then decays to bb, hh or multileptons (from ZZ,WW or ) with extremely small σ×BR. 23 HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS

ttH, H  bb HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS 24

HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS 25

Measuring Higgs Couplings Define the normalized coupling constants (w.r.t. the SM couplings) HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS 26

Measuring Higgs Couplings Can we resolve the degeneracy, disentangle The degeneracy can be broken by parameterize the strength parameters with couplings and introduce constraints which reduce the number of p.o.i. and allow reasonable fits. 27 HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS

Disentangling The Couplings 28 The simplest non-trivial model is (k F, k V ) where all Fermion couplings are set to k F and all Boson couplings to k V HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS

Disentangling The Couplings Note, couplings are dependent on the Higgs mass In the (k F, k V ) benchmark: 29 HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS

Summary of Signal Strength ATLAS bb is low but with large error. 30 ATLAS-CONF HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS

Coupling Benchmarks To make reasonable fits we introduce physics motivated scenarios. Testing the compatibility of the discovered Higgs with the SM is to test also where is it NOT compatible, spotting where NP might sneak in. NP can appear in either the Higgs width and/or in the loops. 31 HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS

Probing Custodial Symmetry WZ is expected to be protected and consistent with unity Large deviations from 1 indicate new physics. 32 ATLAS (NP NL ) Overall fZ, k zz profiled CMS (SM) Overall k Z,K f profiled HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS

The Full Monty I : SM Generic Model I (ATLAS, CMS) All couplings to SM particles are fitted independently k Z and k W assumed positive, fit is sensitive to sign of k t /k W -High rate prefers negative k t -The low measured bb rate does not reflect the sensitivity for k b ATLAS were unlucky -The 5D compatibility with SM is 14% 33 ATLAS-CONF-HIGG HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS

The Full Monty I : SM 34 ATLAS-CONF HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS bb makes 58% of the Higgs width, bb rate measured low, pulls all couplings down

HIGGS PR HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS 35 CMS-PAS-HIG

Vector and Fermion Couplings The loop induces some sensitivity to the relative sign between k t and k W The high observed H  ZZ pulls k W up, allowing high rate and keeps k t positive 36 ATLAS: 2D compatibility with SM 10% ATLAS-CONF HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS

Vector and Fermion Couplings This PR plot tells a story: 37 Tension Drifting apart SM – No Tension ATLAS-CONF HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS

Vector and Fermion Couplings This PR plot tells a story: 38 HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS Tension Drifting apart SM – No Tension

Vector and Fermion Couplings This plot tells a story: 39 HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS Tension Drifting apart SM – No Tension

Probing the Fermion Couplings Asymmetry In models BSM (e.g. 2HDM) there is an asymmetry between k u and k d (u=c,t; d=b,τ) or k ℓ and kq The direct measurement of the Higgs couplings to b and together with the direct (ttH) and loops induced coupling to top allows to measure du Measurement of the coupling to allows a measurement of ℓq The future will bring the Muons and better ttH into the game and improve the measurement 40 The small asymmetry is from b and t interference in ggH loop A vanishing coupling to downtype fermions is excluded at the ~3.6σ(~4σ) ATLAS(CMS) ATLAS-CONF HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS

Asymmetries in Fermion Sector CMS are using a SM-like model while ATLAS are using an NP NL model 41 HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS

Probing the Beyond (kg,k) 42 HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS

Probing the Beyond (kg,k,Br i,u ) 43 HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS

44

HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS 45 LO Interf. Interference can resolve sign of k t Far Off Shell domain STRONG INTERFERENCE

Higgs off-shell Physics HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS 46 Assumptions No NP that affects Higgs couplings but not the continuum Higgs couplings off shell = on shell Far Off Shell domain LO STRONG INTERFERENCE (=1 in CMS)

Higgs off-shell Physics HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS 47 95% CL limit obs. (exp.)  OffShell < 6.7 (7.9) CLs Wondering: Can we do triple Higgs coupling using off-shell Higgs Physics?

HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS 48

Some (still) Rare Decay Channels 49 HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS ATLAS-CONF CMS-PAS-HIG CMS-PAS-HIG

Differential Cross Sections 50 HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS ATLAS-CONF ATLAS-CONF

Highlight t(t)H  t(t) ATLAS-CONF Accidental cancellation of W and t in the di-photon production loop HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS 51

(Pessimistic) Prospects HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS 52 ATL-PHYS-PUB Real Simulations Extrapolations We will do (much) better

HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS 53 Based on M. Kado ICHEP 2014

Conclusions I 54 HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS

Conclusions II 55 HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS

Conclusions III In two years the “discovery of a scalar particle compatible with a SM Higgs Boson” made a phase transition into “precsion measurements” The Higgs moved from the “search” regime to the “SM” regime The last year has proven that reducing the experimental systematics pays The experiments should focus in understanding the detector and do better calibrations. IT TAKES TIME! For now in most important measurements we are statistically limited 56 HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS

Finally Current Higgs activities: Technion: VBF H  ZZ (prospective) Weizmann: BSM H +  tb, H + combination and 2HDM interpretations ttH, H , VH, H , H  cc (prospective with G. Perez) TAU: E. Etzion is the new ATLAS BSM Higgs sub-group convener as of TODAY HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS 57 Good Luck Erez.

BACKUP 58 HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS

Discovery Channel H->WW H->WW->lvlv A challenging channel; No mass reconstruction (mT,mll) Dominant BG WW and tt Understanding Etmiss tails crucial BG from DATA control regions Analysis in categories: (0,1,2 jets VBF,VH)X(SF,DF) Most important systematics from signal cross section (QCD scale, PS and UE, total >10%) 59 Phys. Lett. B 726 (2013), pp CMS: J. High Energy Phys. 01 (2014) HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS

60 HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS

A comment on Interference is extremely important 61 If k t =-1 ggF slightly affected WW unaffected increases Allowing negative k t is extremely important Can be probed with tH HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS

Measuring Higgs Couplings The degeneracy of can be broken by parameterize the strength parameters with couplings and introduce constraints which reduce the number of p.o.i. and allow reasonable fits. m H =125.5 GeV 62 (t,W) interference (t,b) interference HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS

Uncertainties Width Measurements HIGGS ISF HIGGS ISF HIGGS 2014, Eilam Gross HIGGS HIGGS HIGGS HIGGS HIGGS HIGGS 63 L. Quertenmont