Search for Standard Model Scalar Boson Decaying to Fermions at the LHC

Transcription

1 Search for Standard Model Scalar Boson Decaying to Fermions at the LC on behalf of the ATLAS and CMS collaborations Rencontres de Moriond QCD and igh Energy Interactions March 9 th 6 th, 3

2 95% CL limit on σ/σ SM July : observation of a new boson with mass ~ 5 GeV consistent with the Standard Model scalar boson by ATLAS, CMS Couples to bosons: >5σ when considering γγ, ZZ, WW No excess seen in fermionic decay channels Introduction and motivation CDF, D: combining bb channels,.9σ excess in range 535 GeV What can the LC tell us about its coupling to fermions? 5. CMS Preliminary, s = 7-8 TeV, τ τ, L = fb observed 4.5 expected ± σ expected 4. ± σ expected ττ CMS Observed s = TeV, L = fb Expected w/o iggs 5 bb V(bb), combined bb m 95% CL Limit on σ/σ SM 4 3 Summer results CL S Observed CL S Expected CL S Expected ± σ CL S Expected ± σ iggs boson mass Moriond QCD, March 3 95% CL Limit/SM Tevatron Run II Preliminary bb, L. fb ± s.d. Expected ± s.d. Expected SM= June m (GeV/c )

3 Overview and general themes Same basic themes present in each analysis Profit from using best objects b-jets, τ identification, E T miss reconstruction, pileup rejection Events /. Improved b-jet energy ATLAS: add soft lepton p T CMS: energy regression CMS Simulation s = 8 TeV, L =. fb - + Z(l l )(bb) Nominal Regression Signal Efficiency p T Multivariate τ id / isolation Efficiency and momentum resolution (mostly) pileup independent Multi Prong > 5 GeV, <.5 TauBDT loose TauBDT medium TauBDT tight E miss T and pileup Significant improvements in resolution and pileup independence Resolution (GeV) U CMS Preliminary Z µ µ Data Particle Flow E T MC Particle Flow E T Data Particle Flow MVA E T MC Particle Flow MVA E T Standard M bb +5% in mass resolution +-% in sensitivity. Simulation, s = 8 TeV Moriond QCD, March 3 ATLAS Preliminary No serious signal degradation with increased pileup N Vtx 5 Corrected 3 Number of Primary Vertices Critical for ττ 3

4 Overview and general themes Same basic themes present in each analysis Profit from using best objects b-jets, τ identification, E T miss reconstruction, pileup rejection Look at associated production W, Z, qq, tt q Z Z q ` `+ b b q q W, Z W, Z q q + Moriond QCD, March 3 4

5 Overview and general themes Same basic themes present in each analysis Profit from using best objects b-jets, τ identification, E miss T reconstruction, pileup rejection Look at associated production W, Z, qq, tt Split search into separate categories Different S/B, background compositions Constrains backgrounds, systematics Perform simultaneous fit on variable e.g. m bb, m ττ, multivariate analysis (MVA) Shape-based analyses [/GeV] dn/dm ττ 3. CMS Preliminary, s = 7-8 TeV, L = 4.3 fb eτ h jet (VBF) 5 (5 GeV) ττ observed Z ττ Z ee electroweak tt QCD bkg. uncertainty. 3 m ττ Moriond QCD, March 3 5

6 q q Z Z b b q q Z Z ` `+ b b q q W W ` b b g g t t t t W + W b b b b `+ ` q q g g t t t t W + W b b b b `+ ` ` ` bb

7 bb analysis V Vbb bb has largest BR at low mass, but very high background Search for associated production with W or Z Final states with leptons, E miss T, and b-jets Z ll bb W lν bb Z νν bb l (e/μ) + bb l (e/μ) + MET + bb MET + bb q q Z Z ` `+ b b q q Strategy: Require boosted V and, b-tagged jets Shape analysis on signal discriminator ATLAS: invariant mass of b-jets (m bb ) W W CMS: Boosted decision tree (BDT) output Inputs include kinematics, b-tagging information, angular info Moriond QCD, March 3 ` b b q q Z Z b b 7

8 m bb distribution V Vbb Events/ GeV ATLAS Preliminary L dt=3. fb, Lepton Jets, p s = 8 TeV W T > GeV Z W Multijet Top Wb W Zb Z Diboson Pre Fit Data Events / CMS Preliminary s = 7 TeV, L = 5. fb s = 8 TeV, L =. fb pp V; bb Data V(5 GeV) VV V(5 GeV) VV Z + bb Z + udscg W + bb W + udscg Single top tt MC uncert. (stat.) Data/MC.5.5 χ ν =.37 K s =.949 m bb M bb Main backgrounds: V+jets, top Background shapes from simulation, normalizations estimated from data in control regions ATLAS: data driven approach for multi-jet background Moriond QCD, March 3 8

9 Background subtracted V Vbb Events/ GeV 4 3 No separation in p T (V) bins here ATLAS Preliminary L dt=3. fb, L dt=4.7 fb,,, lepton s = 8 TeV s = 7 TeV WZ+ZZ W 5GeV Z 5GeV Data - Bkgd Events / CMS Preliminary s = 7 TeV, L = 5. fb s = 8 TeV, L =. fb pp V; bb Data Sub. stat. uncert. V(5 GeV) VV MC uncert. (stat.) Tighter cut-based selection for m bb m bb - M bb All backgrounds except diboson are subtracted WZ, ZZ production with Z bb has similar signature Diboson background is visible and is well described Shows validity of scalar boson search strategy in bb Moriond QCD, March 3 9

10 Signal extraction V Vbb Categorize by leptons: split by p T (V) and or 3 jets & leptons: split by p T (V) Events/ GeV ATLAS Preliminary W(lν)(bb), jets, high p T (V) L dt=3. fb, Lepton Jets, p s = 8 TeV W T > GeV Z W Multijet Top Wb W Zb Z Diboson Pre Fit Data m bb Events/ GeV 45 Z ATLAS Preliminary Z(νν)(bb), jets, high p T (V) L dt=3. fb, Lepton Jets, E s = 8 TeV miss T > GeV W Multijet Top Wb W Zb Z Diboson Pre Fit Data m bb Categorize into low- and high-p T (V) Additional high-p T (V) category with looser b- tag for W(lν), Z(νν) categories improves sensitivity Entries /.3 Data/MC Z(ee)(bb),high p T (V) CMS Preliminary s = 8TeV, L =. fb - Z(e e + )(bb) Data Z Z + bb Z+udscg tt Single top VV V (5 GeV) MC uncert. (stat.) χ =.333 K =.667 ν MC uncert. (stat. + syst.) MC uncert. (stat.) s BDT output Moriond QCD, March 3 Entries /. Z(νν)(bb),high p T (V) Data/MC 6 Data CMS Preliminary s = 8TeV, L =. fb Z(νν)(bb) V Z + bb Z+udscg W + bb W+udscg tt Single top VV V (5 GeV) MC uncert. (stat.) χ -.8 = K s = ν MC uncert. (stat. + syst.) MC uncert. (stat.) BDT output

11 V(bb) Results V Vbb Observed (expected) limit at 5 GeV.8 (.9) x SM prediction μ = -.4 ±.7 (stat) ±.8 (syst) Observed (expected) limit at 5 GeV.5 (.) x SM prediction μ = ,.σ (.σ) excess 95% C.L. limit on / SM p ATLAS Preliminary ATLAS Preliminary V (bb) Obs. Exp m Observed (CLs) Expected (CLs) ± ± s = 7 TeV, s = 8 TeV, V(bb), combined L dt=4.7 fb, s=7 TeV, Ldt = 4.7 fb Ldt = 3. fb m L dt=3. fb, s=8 TeV Main systematics: b-tag efficiency, JES 4 7 TeV 8 TeV 7 TeV 8 TeV Many analysis improvements 3 5 fb 3 fb.5x more data to analyze SM sensitivity in range! - + Z(l l )(bb) Z(νν)(bb) W(lν)(bb) s = 7 TeV, L = 5. fb s = 8 TeV, L =. fb CMS Preliminary m = 5 GeV 95% Asymptotic CL Limit on σ/σ SM μ = Best fit σ/σ SM Moriond QCD, March m Local p-value CMS Preliminary s = 7 TeV, L = 5 fb s = 8 TeV, L =. fb V(bb), combined fb fb -6 CMS Preliminary s = 7 TeV, L = 5 fb s = 8 TeV, L =. fb V(bb), combined Observed Expected from SM iggs CL S Observed CL S 5 injected CL S Expected CL S Expected ± σ CL S Expected ± σ m σ σ 3σ

12 tt analysis tt ttbb Directly probe top-iggs Yukawa coupling bb is relevant decay at this mass Access tt, anything with enough luminosity Multiple object final state Leptons, E T miss, jets, b-tags Main background: ttbar + jets Strategy: Select isolated, well-identified lepton(s) Categorize based on number of jets, b-tags Shape analysis on signal discriminator ATLAS: m bb ( 6jets, 3tags) or Σp T jets (else) CMS: Artificial neural network (ANN) output Kinematics, b-tagging info, angular info Moriond QCD, March 3 g g t t t t W + W Main systematics: b-tag efficiency JES uncertainty tt + bb uncertainty b ` `+ b b q, ` q, ` b

13 tt tt(bb) results Observed (expected) limit at 5 GeV 3. (.5) x SM prediction Observed (expected) limit at 5 GeV 5.8 (5.) x SM prediction Lepton+Jets and Dilepton ATLAS Preliminary Observed (CLs) Expected (CLs) ± ± s = 7 TeV, tt ( 95% CL limit on σ/ σsm SM / 95% CL Limit on ttbb Ldt = 4.7 fb bb) CMS s = 7 TeV, L = 5. fb; s = 8 TeV, L = 5. fb Observed 8 Expected ± σ 6 Expected ± σ 4 7 TeV 7 TeV 8 TeV 5 fb 5 fb 5 fb ATLAS Preliminary 7 L dt = 4.7 fb e+µ 6 jets, b tags Data ( s = 7 TeV) t t (5) tt ttv W+jets Z+jets Diboson Single top Multijet Tot bkg unc m l + 6 jets + 4 b-tags Events / GeV Events / 6 GeV l + 6 jets + b-tags 35 4 ATLAS Preliminary L dt = 4.7 fb e+µ 6 jets, ll + 3 jets + 3 b-tags 4 b tags Data ( s = 7 TeV) t t (5) tt ttv W+jets Z+jets Diboson Single top Multijet Tot bkg unc. s = 8 TeV, L = 5. fb CMS Dilepton + 3 jets + 3 b-tags tt(5) x m (GeV) l + 6 jets + 4 b-tags Events Events 4 s = 7 TeV, L = 5. fb CMS Lepton + 6 jets + 4 b-tags had T mbb Data/MC Data/MC Data / MC Data / MC.5.5. Moriond QCD, March ANN output ANN output.7.8 ANN output 3

14 g g µ g µ g µ + g µ + μμ q q q q W, Z W, Z q µ µ + q q W W q µ µ +

15 μμ analysis μμ uge background from Z/γ* μμ BR( μμ) =. x -4 at m = 5 GeV Strategy: Select isolated, well-identified muons Require p T μμ > 5 GeV Categorize by (non-)central muons Fit shape of μμ invariant mass (m μμ ) Events /.5 GeV.5 ATLAS Preliminary Simulation Central m =5 GeV CB+Gaussian fit m=4.6 GeV σ CB =.3 GeV FWM=4.9 GeV 3 m µµ Moriond QCD, March 3 m 95% CL Limit on µ Events / GeV Data / SM Data SM (stat) ATLAS Preliminary 9 Single Top W+jets 5 ATLAS Preliminary s = 8 TeV, + - µ µ Observed Bkg. Expected ± σ ± σ Ldt =.7 fb + - µ µ WW tt WZ/ZZ/W γ Z+jets [5 GeV] m = 5 GeV Obs (exp) limit 9.8 (8.) xsm 8 TeV fb Ldt =.7 fb s = 8 TeV m µµ 5

16 g g g g + g + ττ q q W W ` + q q W, Z W, Z q q + q q W W q q +

17 ττ analysis ττ Categorize events based on number of jets, boost of system, lepton (e/μ/τ h ) p T, and final states (eμ, μμ, eτ h, μτ h, τ h τ h ) Strategy: Select isolated, well-identified leptons, τ h Topological cuts to suppress backgrounds e.g. m T or p total T in lτ h, p T (ττ) or ΔR(ττ) in τ h τ h Fit shape of ττ invariant mass (m ττ ) Events CMS Preliminary, s = 8 TeV, L = 9.4 fb µ τ observed h Z ττ electroweak tt QCD bkg. uncertainty Dominant backgrounds m T Z ττ : Use Z μμ data, replace μ by simulated τ decay Normalized from Z μμ events Z ee/μμ : Simulation, corrected for measured l τ h fake rates Multi-jet (QCD): Data, use same sign events with correction ttbar/diboson/w: Simulation, normalized from high-m T region Moriond QCD, March 3 7

18 ττ mττ reconstruction Invariant mass not fully constrained Neutrinos appear as ETmiss e,µ,d 3-% resolution on reconstructed mττ Missing Mass Calculator (MMC) Require relative orientations of ν and decay products be consistent with τ W e, µ, u Maximum Likelihood Method (SVFit) Find best mττ given likelihood functions modeling τ decay kinematics /dmττ [/GeV] CMS Simulation s = 8 TeV µτ.6 h ττ m = 5 GeV.4 Z ττ Moriond QCD, March mττ 8

19 m ττ distributions VBF categories have the highest sensitivity Limited statistics but good S/B Main systematics: τ h energy scale τ h ID efficiency [/GeV] dn/dm ττ Events / 6 GeV τ h τ h had had +-jets VBF Data 5 x (5) Z Multi-jet Others Bkg. uncert. L dt = 3. fb s = 8 TeV ATLAS Preliminary MMC mass m 5x SM signal 3. CMS Preliminary, s = 8 TeV, L = 9.4 fb τ h τ h jet (VBF) 5 (5 GeV) ττ observed Z ττ tt electroweak QCD bkg. uncertainty Events / GeV [/GeV] dn/dm ττ CMS Preliminary, s = 7-8 TeV, L = 4.3 fb, τ τ MMC mass m µτ h ττ μ τ h, e τ h jet (VBF) µ had x SM signal + e had +-jet VBF Data (5) Z Others Fake Bkg. uncert. L dt = 3. fb s = 8 TeV ATLAS Preliminary (5 GeV) ττ observed Z ττ electroweak tt QCD bkg. uncertainty. 3 m ττ Moriond QCD, March m ττ 9

20 ATLAS ττ results ττ 95% CL Limit on / SM Observed CL s Expected CL s ± ± ATLAS Preliminary L dt = 4.6 fb, s = 7 TeV L dt = 3. fb, s = 8 TeV 7 TeV 8 TeV 5 fb 3 fb m weak boson production µ VBF+V B/B SM ATLAS Preliminary L = 4.6 fb, L = 3. fb, s = 7 TeV s = 8 TeV best fit best fit (µ>) 95% Contour 68% Contour SM prediction Background only m = 5 GeV µ ggf B/B SM gluon production Local p - ATLAS Preliminary Observed Expected for SM iggs Boson Ldt = 4.6 fb, s = 7 TeV Ldt = 3. fb, s = 8 TeV Expected for SM iggs Boson at m =5 GeV m Obs (exp) limit =.9 (.) xsm μ =.7 m = 5 GeV Obs (exp) significance =.σ (.7σ).5x more data to analyze SM sensitivity in range! Moriond QCD, March 3

21 CMS ττ results ττ 95% CL limit on σ/σ SM CMS Preliminary, τ τ, L = 4.3 fb observed expected ± σ expected ± σ expected 7 TeV 8 TeV 5 fb 9 fb [/GeV] ττ S/B Weighted dn/dm CMS Preliminary, eµ, eτ h, µτ h, τ h τ h s = 7-8 TeV, L = 4.3 fb 4 (5 GeV) ττ observed Z ττ (5 GeV) ττ Data - Background Bkg. Uncertainty 5 m ττ tt electroweak QCD Local p-value CMS Preliminary, τ τ, L=4.3 fb p-value observed p-value expected σ σ 3σ 4σ 5σ. 3 4 CMS Preliminary, s=7-8 TeV, L=4.3 fb, ττ m 3 m ττ CMS Preliminary, m s=7-8 TeV, L=4.3 fb, ττ m = 5 GeV 4 best fit for σ/σ SM µµ eµ τ h τ h eτ h µτ h V ττ+l Combined Broad excess over m Best-fit μ =. ±.4 Local significance.9σ Channels are consistent Compatible with 5 GeV SM scalar boson Moriond QCD, March 3 m = 5 GeV -Jet -Jet (VBF) V ττ+l Combined 4 best fit for σ/σ SM

22 ττ mass measurement ττ µ best-fit CMS Preliminary, ττ,l = 4.3 fb 7 TeV 8 TeV 5 fb 9 fb Δ( -ln L ) CMS Preliminary, ττ, L = 4.3 fb observed (5 GeV) expected ± ± σ expected σ expected.5..5 σ 95% CL 68% CL BestFit 3 4 m m σ All channels combined: m = +9-7 (stat+syst) GeV Moriond QCD, March 3

23 Summary Strong indication that the new particle couples directly to taus! Most analyses have yet to incorporate full dataset Will have sensitivity beyond SM in V(bb) and (ττ) Expecting to exploit many analysis improvements µ best-fit CMS Preliminary, ττ,l = 4.3 fb µ VBF+V B/B SM ATLAS Preliminary L = 4.6 fb, L = 3. fb, s = 7 TeV s = 8 TeV best fit best fit (µ>) 95% Contour 68% Contour SM prediction Background only m = 5 GeV 95% CL 68% CL BestFit 3 4 m Moriond QCD, March µ ggf B/B SM 3

24 Backup Slides

25 ATLAS Online Luminosity 7 Total Integrated Luminosity [fb ] Total Integrated Luminosity [fb ] Integrated luminosity s = 7 TeV LC Delivered 6 ATLAS Recorded 5 Total Delivered: 5.6 fb Total Recorded: 5.5 fb /6 Total Integrated Luminosity (fb ) p 5 CMS Recorded: 5.55 fb r Ap M ay n Ju Ju l g Au Date (UTC) p Se t Oc 3/5 6/8 / 7/ Day in CMS Integrated Luminosity, pp,, LC Delivered: 6.3 fb 6 6/3 s = 7 TeV Data included from -33 7: to --3 6:9 UTC 7 Total Delivered: 3.3 fb Total Recorded:.7 fb 5 3/8 3/ Day in CMS Integrated Luminosity, pp,, ATLAS Recorded Total Integrated Luminosity (fb ) 3/4 s = 8 TeV LC Delivered 8/ ATLAS Online Luminosity 3 p s = 8 TeV Data included from -4-4 :37 to 6 :49 UTC 5 5 LC Delivered: 3.3 fb CMS Recorded:.79 fb M ay Moriond QCD, March 3 n Ju Ju l g Au p Se Date (UTC) t Oc v No c De 5

26 Documentation Analysis ATLAS CMS V(bb) ATLAS-CONF-6 CMS-PAS-IG-44 tt(bb) ATLAS-CONF-35 arxiv: (μμ) ATLAS-CONF-3- - (ττ) ATLAS-CONF-6 CMS-PAS-IG3-4 CMS-PAS-IG-53 /.] Recorded Luminosity [pb ATLAS Online Luminosity s = 8 TeV, s = 7 TeV,, <µ> = Mean Number of Interactions per Crossing Moriond QCD, March 3 Ldt =.8 fb Ldt = 5. fb, <µ> = 9. 6

27 b-jets Improved energy resolution ATLAS: soft muon energy (p T > 4 GeV) added for b-jets CMS: use of regression techniques to further correct b-jet energy 5% improvement in mass resolution -% increase in sensitivity B-tagging Lifetime-based, use information about track impact parameters, secondary vertices Pileup-jet suppression Multivariate discriminant exploits shape and tracking variables Events / CMS Simulation s = 8 TeV, L =. fb - + Z(l l )(bb) Nominal Regression M bb Moriond QCD, March 3 7

28 b-tagging Scale factor Light jet rejection ATLAS Preliminary tt simulation, p jet T s=7 TeV jet >5 GeV, <.5 MV JetFitterCombNN JetFitterCombNNc IP3D+SV SV b-jet efficiency ATLAS-CONF--43 system8 rel p T combination L = 5 fb ATLAS Preliminary MV7 Data/Sim. b-tag SF Data/Sim. b-tag SF udsg jet efficiency CMS simulation preliminary, TCE TCP SSVE SSVP JP JBP CSV CSVM PtRel System8 IP3D LT s = 7 TeV CMS prelim. at 7 TeV, 4.7 fb b jet efficiency T CMS-PAS-BTV-4 CSVM weighted average fit fit ± (stat syst) p (GeV) CMS prelim. at 7 TeV, 4.7 fb Jet p T.7 Moriond QCD, March 3 p T (GeV) 8

29 τh reconstruction adronic tau reconstruction based on decay modes Charged hadrons + EM strips Efficiency and momentum resolution (mostly) pileup independent ± ±, ± ± ± Signal Efficiency Multivariate identification based on boosted decision tree (BDT) optimized for different working points Multivariate isolation using relative ΣpT of particle flow candidates in concentric rings around τ. TauBDT loose TauBDT medium TauBDT tight Multi Prong p > 5 GeV, <.5 T ATLAS Preliminary Simulation, s = 8 TeV N Vtx Moriond QCD, March 3 9

30 E T miss and pileup suppression ) miss x,y (E Based on ratio of sum p T of tracks from primary vertex and all tracks not associated to reconstructed objects MC default MC Pile-up suppression STVF Data default Data Pile-up suppression STVF Z µµ s = 8 TeV Ldt=.7 fb jets p > GeV T ATLAS Preliminary Npv Resolution (GeV) U CMS Preliminary Z µ µ Multivariate regression based on combining different methods of E T miss reconstruction Data Particle Flow E T MC Particle Flow E T Data Particle Flow MVA E T MC Particle Flow MVA E T 3 Number of Primary Vertices Significant improvement in resolution and dependence on pileup Crucial for τ τ analyses: m ττ reconstruction, background rejection Moriond QCD, March 3 3

31 V(ττ) V ττ [GeV/c ] Events/ CMS Preliminary s = 7 TeV s = 8 TeV vis mττ 95% CL limit on σ/σ SM 8 6 CMS Preliminary 4 observed expected ± σ expected ± σ expected V Vτ τ CMS Preliminary CMS Preliminary llτ ZZ h lτ 4 ZZ h τ h llll ZZ Reducible bkg. Reducible bkg. 8 Reducible bkg. WZ WZ WZ 6 8 m = 5 GeV/c m m 6 = 5 GeV/c = 5 GeV/c 4 Observed Observed Observed 4 s = 7 TeV L = 5. fb s = 7 TeV L = 5. fb L = 5. fb s = 8 TeV L = 9.5 fb L = 9.5 fb s = 8 TeV L = 9.5 fb [GeV/c ] s = 7 TeV s = 8 TeV [GeV/c ] Events/4 L = 5. fb L = 9.5 fb Expected limit m vis 35 4 ττ [GeV/c ] 95% CL limit on σ/σ SM [GeV/c ] Events/ CMS Preliminary vis mττ V Vτ τ s = 7 TeV s = 8 TeV Signal injected L = 5. fb L = 9.5 fb [GeV/c ] m [GeV/c ] Moriond QCD, March m [GeV/c ] 3

32 Consistency with signal ττ 95% CL limit on σ/σ SM CMS Preliminary, τ τ, L = 4.3 fb observed (5 GeV) injected ± σ (5 GeV) injected ± σ (5 GeV) injected 95% CL limit on σ/σ SM CMS Preliminary, τ τ, L = 4.3 fb observed (5 GeV) as BG ± σ (5 GeV) as BG ± σ (5 GeV) as BG m With signal (5) injected. 3 4 m With signal (5) as background Moriond QCD, March 3 3

33 Extension to low mass ττ 95% CL limit on σ/σ SM CMS, Preliminary, τ τ, L = 9.4 fb observed expected ± σ expected ± σ expected 95% CL limit on σ/σ SM CMS, Preliminary, τ τ, L = 9.4 fb observed (5 GeV) as BG ± σ (5 GeV) as BG ± σ (5 GeV) as BG m. 4 m Limit obtained in the background hypothesis, down to m = 9 GeV. Only 8 TeV data are used; combining the eμ, μμ, μτ h, eτ h, and τ h τ h channels. The μμ and V channels are not included. Same as (left) but in a background hypothesis including this SM iggs boson signal as a background Moriond QCD, March 3 33

34 Embedding Z ττ ττ Validation of embedding technique with Z μμ data. Procedure does not introduce any significant bias on the reconstruction of the event properties. Arbitrary Units Arbitrary Units Z µµ Selection Z µµ Embedded Z µµ Data L dt = 3. fb s = 8 TeV ATLAS Preliminary e had miss E T Moriond QCD, March 3 + µ had Preselection Z Embedded Z Alpgen MC Emb. syst. L dt = 3. fb s = 8 TeV ATLAS Preliminary MMC mass m Arbitrary Units Arbitrary Units ee + eµ + µµ Preselection Z Embedded Z Alpgen MC Emb. syst. L dt = 3. fb s = 8 TeV ATLAS Preliminary MMC mass m MMC mass m had had Preselection Z Embedded Z Alpgen MC Emb. syst. L dt = 3. fb s = 8 TeV ATLAS Preliminary 34

35 b-jet regression validation V Vbb Events / CMS Preliminary s = 8 TeV, L =. fb - + Data Z(l l )+bb Nominal Regression Events / GeV (Normalized).6 CMS Preliminary s = 8 TeV, L =. fb W(µν)(bb) Data Data (Corr.) Before Correction: Mean = 7. ±.3 Sigma =.4 ± 3. After Correction: Mean = 74. ±.4 Sigma = 8. ± balance Validation of the regression performance on data using the Z and jet balance in a Z+bb enriched selection on 8 TeV data. p T (CSV-ordered Jets) M top Validation on 8 TeV data using the reco top quark mass. Shapes are shown before/after regression. Top quark candidate is reconstructed using the b-jet of highest CSV discriminant. Moriond QCD, March 3 35

36 Categories ττ g q No fit for signal Number of jets g g + q q W, Z W, Z q + τ p T -jet, low p T Large background, constrains nuisances -jet, low p T Enhancement from jet requirement -jet, VBF jets, Δη(jj) > 3.5 (no other jet in gap), m(jj) > 5 GeV -jet, high p T Large background, constrains nuisances eμ, μμ, μτ h, eτ h -jet, high p T Enhancement from jet and p T requirement -jet, high p τ h τ h T jet p T > 5 GeV, p T () > 4 GeV τ -jet, VBF h τ h jets, Δη(jj) > 3.5 (no other jet in gap), m(jj) > 5 GeV, p T () > GeV Moriond QCD, March 3 36

37 Limits by category/final state ττ 95% CL limit on σ/σ SM CMS Preliminary, ττ, L=3.4 fb 5. Expected Limit 4.5 -Jet -Jet (VBF) 4. V ττ+l(l) 3.5 ττ + V ττ+l % CL limit on σ/σ SM CMS Preliminary, ττ, L=3.4 fb Expected Limit µµ τ h τ h eµ eτ h µτ h V ττ+l(l) ττ + V ττ+l m Expected limit at 95% CL for the different event categories. 3 4 m Expected limit at 95% CL for different final states. Moriond QCD, March 3 37

38 Systematics ττ ττ Moriond QCD, March 3 38

39 Systematics ττ ττ Table : Main systematic uncertainties entering the analysis. The symbol indicates that the uncertainty is anti-correlated with respect to other categories. The (*) symbol indicates correlation between separate channels. The ( ) symbol indicates correlation between separate categories. In the instance where ex. vbf is indicated, an additional uncorrelated nuisance is added to account for statistical uncertainties. Experimental Uncertainties Propagation into Event Categories Uncertainty Uncert. -Jet -Jet VBF Electron ID & Trigger ( *) ±% ±% ±% ±% Muon ID & Trigger ( *) ±% ±% ±% ±% Tau ID & Trigger ( ) ±8% ±8% ±8% ±8% Tau Energy Scale ( ) ±3% ±3% ±3% ±3% Electron Energy Scale ( ) ±% ±% ±% ±% JES (Norm.) ( *) ±.5 5% 3 5% ± 6% ±5 % MET (Norm.) ( *) ±5% ±5 7% ± 7% ±5 8% b-tag E ciency ( *) ±% % 3% 3% Mis-Tagging ( *) ±3% % % 3% Norm. Z production ( *) ±3% ±3% ±3% ±3% Z! Category ±3% ± 5% ±3 5% ± 3% Norm. t t ( * ex.vbf) ±% ±% ±% ± 33% Norm. Diboson ( * ex. vbf) ±5 3% ±5 3% ±5 3% ±5 % Norm. QCD Multijet ±6 3% ±6 3% ±9 3% ±9 35% Lumi 7 TeV (8 TeV) ±.(4.)% ±.(4.)% ±.(4.)% ±.(4.)% Norm. W +jets ± 3% ± 7% ± 33% ±.4% 3% Norm. Z! ``: efakes h ( ) ±% ±% ±36% ±% Norm. Z! ``: µ fakes h ( ) ±3% ±3% ±3% ±3% Norm. Z! ``: jetfakes h ±% ±% ±% ±4% 39

40 Background systematics V Vbb Moriond QCD, March 3 4

41 Signal systematics V Vbb Moriond QCD, March 3 4

42 Systematics V Vbb 4

43 Systematics tt ttbb Moriond QCD, March 3 43

44 Systematics tt ttbb Moriond QCD, March 3 44

45 Scale factors V Vbb From control regions From fit to data Moriond QCD, March 3 45

46 BDT variables V Vbb BDT for signal discriminator BDT regression variables Raw jet p T, corrected jet p T, leading track p T of jet, secondary vertex information (3D flight length, mass, p T ), number of jet constituents, soft leptons in jet, E T miss, delta phi between E T miss and jet 46

47 Sample selection V Vbb 47

48 Sample selection V Vbb 48

49 Scale factors V Vbb 49

50 Control regions Zll V Vbb 5

51 Control regions Wlnu V Vbb 5

52 Control regions Znunu V Vbb 5

53 Background composition tt ttbb Moriond QCD, March 3 53

54 S/sqrt(B) by category tt ttbb Moriond QCD, March 3 54

55 m bb reconstruction tt ttbb Arbitrary units jets, 3 b-tags All iggs particle matched (9.8%) b-quarks from iggs matched (3.3%) All partons matched (4.7%) ATLAS Preliminary (Simulation) m = 5 GeV Arbitrary units.5..5 ATLAS Preliminary (Simulation) 5 jets, 4 b-tags Total background tt (m = 5 GeV)....5 Arbitrary units m bb 6 jets, 4 b-tags All iggs particle matched (6.4%) b-quarks from iggs matched (.%) All partons matched (7.5%) ATLAS Preliminary (Simulation) m = 5 GeV Kinematic likelihood fitter Arbitrary units had T ATLAS Preliminary (Simulation) 6 jets, 4 b-tags Total background tt (m = 5 GeV) m Moriond bb QCD, March M bb 55

56 ANN input variables tt ttbb Moriond QCD, March 3 56

57 ANN output tt ttbb Events 8 7 CMS s = 8 TeV, L = 5. fb Lepton + 6 jets + 3 b-tags Events 5 CMS s = 8 TeV, L = 5. fb Lepton + 5 jets + 4 b-tags Events CMS s = 8 TeV, L = 5. fb 35 Lepton + 6 jets + 4 b-tags Data/MC Data/MC Data/MC ANN output ANN output ANN output Events 6 5 CMS s = 7 TeV, L = 5. fb Lepton + 6 jets + 3 b-tags Events CMS s = 7 TeV, L = 5. fb Lepton + 5 jets + 4 b-tags Events 4 CMS s = 7 TeV, L = 5. fb Lepton + 6 jets + 4 b-tags Data/MC Data/MC ANN output Data/MC ANN output ANN output Moriond QCD, March ANN output 57

58 Selection ττ ττ 58

59 Selection ττ ττ 59

60 Selection ττ ττ 6

61 Signal systematics μμ Moriond QCD, March 3 6

62 Normalization systematics μμ Moriond QCD, March 3 6

63 Background fit μμ Events /.5 GeV 5 5 ATLAS Preliminary s = 8 TeV Ldt =.7 fb Central Simulation Fit model Breit-Wigner Exponential χ /ndof =.9 Events /.5 GeV ATLAS Preliminary s = 8 TeV Ldt =.7 fb Non-central Simulation Fit model Breit-Wigner Exponential χ /ndof =.98 Data-Fit Di-muon mass - Events /.5 GeV m µµ ATLAS Preliminary Central s = 8 TeV Ldt =.7 fb Data Fit model Breit-Wigner Exponential χ /ndof =. Data-Fit Events /.5 GeV - p T (μμ) < 5 GeV m µµ ATLAS Preliminary Non-central s = 8 TeV Ldt =.7 fb Data Fit model Breit-Wigner Exponential χ /ndof =. Data-Fit Di-muon mass Di-muon mass m µµ Data-Fit Moriond QCD, March m µµ 63