[ ] Search for tth and th production (not including H bb) at the LHC. !!!!! Top2015 Ischia. Josh McFayden

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1 Search for tth and th production (not including H bb) at the LHC [ ] Josh McFayden on behalf of the ATLAS and CMS collaborations Top Ischia 7/9/

2 Search for tth and th production (not including H bb) at the LHC Josh McFayden on behalf of the ATLAS and CMS collaborations Top Ischia 7/9/

3 Introduction Since the Higgs discoveries the focus of experiment has been to measure its properties including its coupling to SM particles. Higgs observed decaying to H γγ, H ZZ* 4l, H WW* lυlυ, evidence for H ττ. The large mass of the top quark implies a top Yukawa coupling ~. There is already sensitivity in to the top-higgs coupling from ggf Higgs production and from the decay to photons via loop interactions: g t t t H H t g t t 3 Josh McFayden Top 7/9/

4 Introduction Production in association with ttbar would permit a direct measurement of the top-higgs coupling Removing possible BSM effects in the loops. Production in association with a single top quark is sensitive to W-t interference and relative sign of the top-higgs coupling g g t t t H t Tree level interference in all channels and in Hγγ loop for H γγ 4 Josh McFayden Top 7/9/

Analyses covered ATLAS and CMS analyses searching for a Higgs produced in association with top quark pairs (tth) and single top quarks (th) are presented.

Signatures are di-photons, same-sign (SS) di-lepton and multi-lepton final states Higgs BR + Total Uncert - -3-4 bb WW gg cc ZZ Z µµ 3 4 6 7 8 9 3 M H [GeV] LHC HIGGS XS

5 Analyses covered ATLAS and CMS analyses searching for a Higgs produced in association with top quark pairs (tth) and single top quarks (th) are presented. This talk focuses on searches in decay modes not including H bb In reality this means H γγ, H ZZ*, H WW* and H ττ. Signatures are di-photons, same-sign (SS) di-lepton and multi-lepton final states Higgs BR + Total Uncert bb WW gg cc ZZ Z µµ M H [GeV] LHC HIGGS XS WG 3 H WW =.4 H ττ =.6 H ZZ =.8 H γγ =. t[t]h( γγ): Physics Letters B 74 () -4 t[t]h( leptons): Physics Letters B 749 () 9-4 tth(h all): J. High Energy Phys. 9 (4) 87 th( γγ): HIG4- tth(h leptons): HIG3- th( leptons): HIG4-6 Josh McFayden Top 7/9/

6 6 Josh McFayden Josh McFayden MC performance Top // 7/9/ H γγ

7 7 Josh McFayden Top 7/9/ t[t]h γγ Analysis strategy ATLAS and CMS use both s = 7 & 8 TeV datasets for this analysis. ATLAS includes th in the definition of signal whilst CMS has a separate analysis. Two signal regions defined by top decay modes Leptonic and hadronic categories. Use excellent m γγ resolution to extract signal peak from falling continuum background. Background estimated from data using m γγ sidebands. Signal strength, μ, is extracted from fit to m γγ distribution Higgs mass is fixed while μ is allowed to float but is common across the different signal regions.

8 8 Josh McFayden Top 7/9/ t[t]h γγ Results Dominant systematic uncertainties are: Photon ID Background modelling Jet energy scale Theory & MC modelling Results are consistent with the SM expectation / GeV / GeV Background fit µ =.4 ATLAS s = 8 TeV Ldt =.3 fb tth, H γ γ, m H 8 TeV leptonic category =.4 GeV [GeV] Background fit µ =.4 ATLAS m γ γ s = 8 TeV Ldt =.3 fb tth, H γ γ, m H 8 TeV hadronic category =.4 GeV CMS tth γγ leptonic 6 Bkg fit ±σ ±σ 4 m H =.6GeV 3 s = 8 TeV, L = 9.7 fb (GeV) 4 3 CMS tth γγ hadronic m γγ s = 8 TeV, L = 9.7fb 6 Bkg fit ±σ ±σ m H =.6GeV [GeV] m γ γ (GeV) m γγ

9 t[t]h γγ tth Interpretation The H γγ observed (exp.) 9%CL upper limits on σ/σsm: ATLAS: 6.7 ( ) CMS: 7.4 ( ) The H γγ best-fit tth signal strengths: ATLAS: μtth= CMS: μtth= CMS s = 7 TeV,.-. fb ; s = 8 TeV, fb ATLAS - s=7 TeV, L dt=4. fb s=8 TeV, L dt=.3 fb γγ bb Expected ± σ Expected ± σ Expected (sig. inj.) Observed Hadronic τ h τ h Combined 9 Leptonic 3 3 9% CL limit on σ tt H /σ tt H SM at m H t Expected (σ t H =) ± t Expected (σ t H =) ± Observed SM signal injected σ σ =.4 GeV 4l 3l Same-Sign l Combination 9% CL limit on σ/σ SM at m H =.6 GeV Josh McFayden Top 7/9/

10 t[t]h γγ th Interpretation Results can also be interpreted in terms of the scale of the top Yukawa coupling, κ t or C t. At the 9% CL ATLAS exclude κ t <.3 and κ t > 8.. Expectation w.r.t SM Limits constrain BSM models ATLAS tth, H γ γ s = 8 TeV, m H =.4 GeV SM BR(H γ γ ) BR SM (H γ γ ) σ(tth)/σ SM (tth) σ(th)/σ SM (th) κ t th Results: - ATLAS result included in tth search - CMS dedicated search for thq. No events observed: 9%CL upper limit on σ/σsm of 4. for inverted coupling (Ct=). γ ) )(κ t ) γ γ γ σ BR(H σ BR(H 9% CL limit on 3 - ATLAS - / ( GeV) κ Top 7/9/ t Josh McFayden CMS Preliminary, L = 9.7 fb at Diphoton Mass [GeV] Ldt = 4. fb Ldt =.3 fb s = 7 TeV Observed CL s limit Expected CL s limit ± σ ± σ,, thq (Ct = ) Extra tth (Ct = ) tth () VH () s = 8 TeV s = 8 TeV

11 Josh McFayden Josh McFayden MC performance Top // 7/9/ H leptons

tth leptons Analysis strategy Final state considered is the following: p p t t H b b W W W W b b W W τ τ l=e,μ Signal regions selection: Common selection: Fit strategy: l SS τhad 4j, b 4j, btight

12 tth leptons Analysis strategy Final state considered is the following: p p t t H b b W W W W b b W W τ τ l=e,μ Signal regions selection: Common selection: Fit strategy: l SS τhad 4j, b 4j, btight bloose l SS τhad 4j, b 3l 4j, b 3j, b j, btight bloose 4l j, b, Zenriched/deprived Njets τhad l, 3j, b Within H bb framework m(ll) cuts veto for low mass resonances & Z candidates miss ET /HT - LD cut to remove Z+jets Yield in SRs ATLAS signal category by Higgs decay mode (CMS ~same) Shape: BDT bins & Njets (lτhad split SRs by Njets & l-flav) (Njets is used in 4l-only) Josh McFayden Top 7/9/

tth leptons Backgrounds Dominant backgrounds can be split into two categories Irreducible: ttv, diboson(+bjet) Use validation regions to validate MC with data Reducible: non-prompt leptons Use

13 tth leptons Backgrounds Dominant backgrounds can be split into two categories Irreducible: ttv, diboson(+bjet) Use validation regions to validate MC with data Reducible: non-prompt leptons Use control regions with loosened isolation requirements to extrapolate to signal region 4 ± µ ± CMS tth, e channel s = 8 TeV, L = 9.6 fb ttw/z/h ttγ Others Non Pr Trailing lepton p T (GeV) Josh McFayden Top 7/9/

14 tth leptons Results Dominant systematic uncertainties: 4 Non-prompt lepton background estimation Theory & MC modelling Jet energy scale Signal strength extraction from fit to: ATLAS Charge misid Rare s = 8 TeV,.3 fb lτ had category signal region ATLAS s = 8 TeV,.3 fb 8 3l category 6 yields Shape of 4 BDT & N jet distribution(s) Total unc. tth() X Number of jets ttw Total unc. tth() X.4 VV ttz ttw Rare Number of jets VV ttz tth ttw ttz/γ* ttγ WZ Others Non Pr Ch misid tth x 3 tth ttw 3 ttz/γ* ttγ WZ Others Fakes tth x 3 ± µ ± CMS tth, e channel s = 8 TeV, L = 9. fb BDT output CMS tth, 3l channel s = 8 TeV, L = 9. fb BDT output Josh McFayden Top 7/9/

15 tth leptons Limits on σ/σsm The results are compatible with the SM expectation, although an excess is observed by both experiments. l SS and 3l categories are the most sensitive The H leptons observed (exp.) 9%CL upper limits on σ/σ SM : ATLAS - 4l: 8 ( +8-4) CMS - 4l: 6.8 ( ) 3l: 6.8 ( ) 3l: 7. ( ) lτhad: 6.7 ( ) l: 9. ( ) lτ had 4l ATLAS s = 8 TeV,.3 fb γγ bb CMS s = 7 TeV,.-. fb ; s = 8 TeV, fb Expected ± σ Expected ± σ Expected (sig. inj.) Observed lτ had 3l lτ had All Observed CL s limit Expected CL s Expected CL signal Injected s Expected ± σ Expected ± σ τ h τ h 4l 3l Same-Sign l Combination 9% CL S limit on µ=σ/σ SM 9% CL limit on σ/σ SM at m H =.6 GeV Josh McFayden Top 7/9/

16 tth leptons Signal strength The results are compatible with the SM expectation, although an excess is observed by both experiments. l SS and 3l categories are the most sensitive. The H leptons observed best-fit signal strengths: ATLAS - 4l: CMS - 4l: l: l: lτhad: CMS l:.3 +. s.8 γγ = 7 TeV,.-. fb ; s = 8 TeV, fb bb τ h τ h CMS s = 7 TeV,.-. fb ; s = 8 TeV, fb τ h τ h 4l 4l 3l 3l Same-Sign l Same-Sign l Combination 6 Combination Best fit σ/σ SM at m H =.6 GeV Josh McFayden Top 7/9/

17 +. ggf+tth: µ = VBF+VH: µ = tth All +.4 tth combination results Overall: µ = H WW* +.9 ggf: µ = The combined VBF: µ =.8.36 observed (exp.) 9%CL upper limits on σ/σ -.47 SM : = VH: µ.3.36 ATLAS: 3. (.4) +.43 H ττ ATLAS Overall: µ =.43 Individual H Zγ +4. Overall: analysis µ =.7 s = 7 TeV, fb μ ggf = s = 8 TeV,.3 fb ggf: µ =..36. The +.9 VBF+VH: combined µ =.4 observed best-fit signal strengths: =. +.4 Overall: µ VH Vbb ATLAS: μ= CMS: μ= H µµ tth WH: µ =. ZH: µ =. Overall: µ = bb: µ = Multilepton: µ =. γγ: µ =.3 μ VH =.8± μ VBF =.3±.3.. (GeV) m H.4 ATLAS 68% CL: 9% CL: ATLAS 68% CL: 9% CL: Input measurements ± σ on µ s =7TeV,4. 4.7fb s =8TeV,.3fb 4 Signal strength (µ) s =7TeV,4. 4.7fb s =8TeV,.3fb µ µ γγ bb τ h τ h 4l 3l Same-Sign l ggh Combination CMS: 4. ( ) CMS = = VBF µ =.9 VH -.36 CMS CMS s = 7 TeV,.-. fb ; s = 8 TeV, fb 9.7 fb (8 TeV) +. fb (7 TeV) 68% CL 9% CL Best fit σ/σ SM at m H =.6 GeV 9.7 fb (8 TeV) +. fb (7 TeV) 68% CL 9% CL 7 μ tth =.8±.8 μ ggf = μ VBF =.3±.3 μ VH =.8±.36 m H =.36GeV... 3 Signal strength (μ).36 hep-ph µ µ tth ggh =.9 = µ HIG4-9 Parameter value =.6 VBF -.34 Josh McFayden Top 7/9/

18 8 Josh McFayden Top 7/9/ th leptons Analysis strategy Search for single top+h production in leptonic channels Focus on the H WW* and H ττ decay modes. l SS (e ± μ ± and μ ± μ ± ) and 3l selections Several discriminating kinematic variables are combined into a single likelihood discriminant for each channel. The dominant backgrounds: Non-prompt leptons Control regions defined by looser lepton selections then used to extract extrapolation factors back to signal regions ttw Estimated purely from MC.

19 th leptons Likelihood discriminant CMS Preliminary 9.6 fb (8 TeV) 3 thq (Ct = ) ttw, ttz, tth WZ W ± W ± qq Ch. Mis.Id CMS Preliminary 9.6 fb (8 TeV) thq (Ct = ) ttw, ttz, tth WZ W ± W ± qq Ch. Mis.Id 4 3 CMS Preliminary 9.7 fb thq (Ct = ) thw (Ct = ) diboson, WVV ttw,ttz,tth (8 TeV) CMS Preliminary 9.7 fb thq (Ct = ) thw (Ct = ) diboson, WVV ttw,ttz,tth (8 TeV) Forward Jet η Gap 3 CMS Preliminary 9.6 fb (8 TeV) thq (Ct = ) ttw, ttz, tth WZ W ± W ± qq Lepton Charge 3 thq (Ct = ) CMS Preliminary 9.6 fb (8 TeV) ttw, ttz, tth WZ W ± W ± qq Ch. Mis.Id - - total charge 4 3 CMS Preliminary 9.7 fb thq (Ct = ) thw (Ct = ) diboson, WVV ttw,ttz,tth (8 TeV) η(q,b) CMS Preliminary 9.7 fb thq (Ct = ) thw (Ct = ) diboson, WVV ttw,ttz,tth (8 TeV) (p > GeV) N jets T φ (l, l ) #central jets min ( R(l,l)) Josh McFayden Top 7/9/

20 th leptons Likelihood discriminant 3 thq (Ct = ) CMS Preliminary 9.6 fb (8 TeV) ttw, ttz, tth WZ W ± W ± qq Ch. Mis.Id thq (Ct = ) thq (Ct = ) thw (Ct = ) thw (Ct = ) 4 4 CMS Preliminary 9.6 fb (84 TeV) CMS Preliminary 9.6 fb (8 TeV) diboson, WVV CMS Preliminary 9.6 fb (8 diboson, TeV) WVV 6 4 ttw,ttz,tth ttw,ttz,tth e ± µ ± µ ± µ ± channel thq (Ct = ) channel thq (Ct = ) 3 lepton channel 3 3 thq (Ct = ) ttw, ttz, tth 3 ttw, ttz, tth ttw, ttz, tth WZ WZ ± ± VV, WVV W W qq ± ± W W qq 3 ttγ, ttγ* Rare SM 4 Rare SM. 4 3 Ch. Mis.Id Forward Jet η Gap Lepton Charge - - CMS Preliminary 9.6 fb (8 TeV) CMS Preliminary 9.6 fb (8 TeV) total charge total charge 3 3 thq (Ct = ) thq (Ct = ) CMS Preliminary 9.7 fb (8 TeV) CMS Preliminary 9.7 fb (8 TeV) ttw, ttz, tth ttw, ttz, tth WZ WZ W ± W ± qq W ± W ± qq thq (Ct = ) thq (Ct = ) 4 4 thw (Ct = ) thw (Ct = ) 4 Ch. Mis.Id 3 3 diboson, WVV diboson, WVV ttw,ttz,tth ttw,ttz,tth thq Likelihood thq Likelihood thq Likelihood 8 6 CMS Preliminary 9.6 fb (8 TeV) thq (Ct = ) ttw, ttz, tth WZ W ± W ± qq Ch. Mis.Id CMS Preliminary 9.7 fb (8 TeV) CMS Preliminary 9.7 fb (8 TeV) (p > GeV) N jets T φ (l, l ) #central jets min ( R(l,l)) Josh McFayden Top 7/9/

21 th leptons Results & limits The results are compatible with the SM expectation. The dominant systematic uncertainty comes from the estimation of the non-prompt lepton backgrounds. A simultaneous fit to the likelihood discriminators is used to extract the signal cross section upper limit. Combined 9% CL upper limit assuming Ct= on σ/σsm: observed: 6.7, expected: ± ± ± ± 6. Total Background 6.7± 8.9.3± ± 6. th(tt)w. ±..3 ±.4. ±. th(ww)w.8 ±.9.47 ±.48.3 ±.3 th(tt)q.9 ±.6.9 ±.9.6 ±.8 th(ww)q. ± ± ±.8 Total Signal 3.3±.7.± ± limit on σ/σ Ct= 9% C.L. CL S 3 CMS Preliminary 9.7 fb (8 TeV) pp thq t blν, H WW C t =, m = GeV H CL S Observed CL S Expected ± σ CL S exp. ± σ CL S exp. µ ± µ ± ± µ ± e 3 Leptons Combination Josh McFayden Top 7/9/

22 Josh McFayden Top 7/9/ ATLAS & CMS Combination Recently ATLAS & CMS published the Run combined measurements of the Higgs production and decay rates and constraints on its couplings. This includes the combined value for the tth signal strength: μ tth = Significance: 4.4σ (.σ expected) Total combined signal strength: μ =

23 3 Josh McFayden Top 7/9/ Summary and outlook First searches for the production of a Higgs boson in association with top(s) has been performed during Run These have allowed direct measurement of magnitude and sign of top Yukawa coupling, a key parameter of EWSB in SM The prospects for t[t]h measurements are good in Run-. Improvement upon on Run sensitivity should be fast. At 3 TeV the tth cross section is a factor of 4 larger than in Run. Greater precision for top Yukawa measurement. (pp H+X) [pb] pp H (NNLO+NNLL QCD + NLO EW) pp qqh (NNLO QCD + NLO EW) pp WH (NNLO QCD + NLO EW) pp ZH (NNLO QCD + NLO EW) pp bbh (NNLO and NLO QCD) pp tth (NLO QCD) = GeV MSTW s [TeV] M H LHC HIGGS XS WG 4

24 4 Josh McFayden Josh McFayden MC performance Top // 7/9/ Back-ups

25 Josh McFayden Top 7/9/ tth γγ Selection Objects: γ: ET>.3,. mγγ, η <.37 (excl. transition region),<mγγ<6 e: ET> GeV, η <.37, [E,p]Tcone/pT<%,% E T (e) μ: pt>, η <.7 [E,p]Tcone/pT<%,% pt(μ) jets: pt > GeV and η <., btagging (8TeV): 6%,7%,8% working points: Leptonic: l, bj(8%), ETmiss> GeV, Z-veto: 84<m eγ <94 GeV Hadronic: 6j bj(8%), j(3 GeV) bj(7%), 6j(3 GeV) bj(6%)

26 tth γγ Generators The tth signal is modelled using the PYTHIA6. The background processes ttw, ttz, tt+jets, Drell Yan+jets, W+jets, ZZ +jets, WW+jets, and WZ+jets are all generated with the MADGRAPH. The rare WWZ, WWW, tt + γ+jets, and ttww processes are generated similarly. Single top is generated with POWHEG. tth: PowHel"+Pythia8 thqb: MadGraph+Pythia8 (4-FS) WtH: MadGraph_aMC@NLO+Herwig++ (-FS) ggh and VBF: Powheg+Pythia8 VH: Pythia8 6 Josh McFayden Top 7/9/

27 tth γγ Yields & uncertainties 7 Josh McFayden Top 7/9/ <mγγ<3 GeV:

28 tth leptons Selection CMS b-tagging: medium:7% eff, % mistag, loose:8% eff, % mistag ATLAS: jets: p T > GeV and η <., b-tagging: eft 7%, % mistag p T (l)> GeV τ had p T > GeV and η <.47 lτ had : p T (l)>, GeV, [E,p T ] cone /p T :<., η(e) <.37 3l: Σq(l)=±, p T (l)> GeV (same charge l) lτ had : p T (l)>, GeV, τ had opposite charge to l s lτ had : p T (l)>, GeV, τ had opposite charge to l s 4l: Σq(l)=, p T (l)>, GeV, <m 4l < GeV, Z enriched/depleted ll=sfos 8 Josh McFayden Top 7/9/

29 tth leptons Yields 9 Josh McFayden Top 7/9/

30 tth leptons Systematic uncertainties 3 Josh McFayden Top 7/9/

31 3 Josh McFayden Top 7/9/ tth leptons ATLAS ttv background Validation regions for the ttv background. ttz and ttw enhanced regions to validate MC against data / GeV ATLAS 4 ttw 4 s = 8 TeV,.3 fb Rare Total unc. VV ttz VR 3 tth() ttz 3 3 s = 8 TeV,.3 fb t t W VR ATLAS Preliminary Rare 3 Charge misid tth() VV ttz ttw / Bkg 3 / Bkg 3 3 m ll [GeV] 3 Number of jets

32 tth leptons Other signal regions - Njets 4 ATLAS s = 8 TeV,.3 fb lτ had category ttw Total unc. tth() Rare Number of jets VV ttz lτhad 8 lτhad 4l 6 4 ATLAS s = 8 TeV,.3 fb lτ had category ttw Rare Number of jets tt Total unc. tth() X.4 VV ttz 4 ATLAS s = 8 TeV,.3 fb 4l category ttw Total unc. tth() Rare Number of jets VV ttz CMS tth, µ ± µ ± channel s = 8 TeV, L = 9. fb ± µ ± CMS tth, e channel s = 8 TeV, L = 9. fb 3 tth tth 3 tth 3 l(μμ) ttw l(eμ) ttw ttz/γ* 4l ttz/γ* ttz/γ* ZZ WZ 4 ttγ. Non Pr Others WZ Others Non Pr Others tth x tth x 3 Non Pr Ch misid. tth x. CMS tth, 4l channel s = 8 TeV, L = 9. fb N(jet) N(jet) N(jet) Josh McFayden Top 7/9/

33 tth leptons CMS τhad tth(.6) x 3 tt CMS tth τh τ h s = 8 TeV, L = 9.3 fb Lep + τ h τ h + jets + b-tag 3 3 CMS tth τh τ h s = 8 TeV, L = 9.3 fb Lep + τ h τ h + 3 jets + b-tags Single t tt + W,Z EWK Bkg. Unc. /MC Fit ±σ Fit ±σ -.8 Fit ±-.6 σ -.4 Fit ±-. σ BDT output /MC BDT output 33 Josh McFayden Top 7/9/

34 tth leptons Generators The tth signal is modelled using the PYTHIA6. The background processes ttw, ttz, tt+jets, Drell Yan+jets, W+jets, ZZ+jets, WW+jets, and WZ+jets are all generated with the MADGRAPH. The rare WWZ, WWW, tt + γ+jets, and ttww processes are generated similarly. Single top is generated with POWHEG. 34 Josh McFayden Top 7/9/

35 ttv 8 TeV results 3 Josh McFayden Top 7/9/

36 tth leptons ℓτhad event display Event display for candidate event in the ℓτhad category. Muon Electron, pt = 8, 3 GeV Non-b-tagged jets 36 pt = GeV b-tagged jets pt = 6 GeV τ candidate pt = 4 GeV pt = 76, 6 GeV Josh McFayden Top 7/9/

37 37 Josh McFayden Top 7/9/ tth leptons μtth μ extraction dependant on ttw and ttz cross sections:

38 38 Josh McFayden Top 7/9/ th leptons Yields and uncertainties Process µµ eµ ``` W ± W ± qq 4.6 ± ±.8 WZ, WW, ZZ.47 ± ± 3..9 ±.4 Rare SM bkg..4 ±.68.7 ±.3. ±.3 ttg. ±..4 ±.4 ttg.9 ±.3. ±.6 ttz.3 ±.4.87 ±.. ±.36 ttw ±.8 ± ± ±. tth.6 ± ±.47. ±.8 Charge Mis-ID 6.96 ± ± ± ± 6. Total Background 6.7± 8.9.3± ± 6. th(tt)w. ±..3 ±.4. ±. th(ww)w.8 ±.9.47 ±.48.3 ±.3 th(tt)q.9 ±.6.9 ±.9.6 ±.8 th(ww)q. ± ± ±.8 Total Signal 3.3±.7.± ± yields and post-fit expected backgrounds after the likelihood pre ± ± Source of uncertainty Type Exclusive Removal (%) source (%) Luminosity rate < < Pileup rate < < Lepton trigger efficiency rate < < Lepton selection efficiencies rate < < Electron energy scale shape < < Jet energy corrections shape < < b-tagging efficiencies shape < < Flavour Scheme rate Higgs branching fractions rate < < Renormalization/factorization scale rate < < Parton density functions (pdf) rate < < Irreducible background normalization rate < < µ fake-rate normalization (SS) rate 6 9 e fake-rate normalization (SS) rate µ fake-rate leptons shape (SS) shape < e fake-rate leptons shape (SS) shape < Non-prompt closure test (3`) rate 3 3 QCD control region variation for fake-rate (3`) shape < Fake-rate variation within stat. uncert. (3`) shape < Charge misidentification (SS) rate < < Stat. uncert. for non-prompt leptons (3`) shape 3 Stat. uncert. for non-prompt leptons (SS) shape 4 3 le 4: Summary of the impact of single systematic uncertainties. Deterioration of a hypot

Evidence for tth production at ATLAS

Evidence for tth production at ATLAS Rohin T Narayan on behalf of the ATLAS collaboration Nov-6-2017, Higgs couplings Heidelberg Motivation Fermion masses are generated through Yukawa interaction Heaviest