Search for diboson resonances at CMS

Transcription

1 Search for diboson resonances at CMS identifying highly energetic boson decays and discriminating new physics signals from the standard model background Clemens Lange (CERN) DESY Physics Seminar Hamburg/Zeuthen 3 st May/ st June 206

2 About diboson resonances [ heavy resonances? boson jets? background estimation? ( wasn t ) there this diphoton resonance? Clemens Lange - Diboson resonances searches at CMS 2

3 We have a problem >how can we explain the big difference between the weak force and gravity? µ 2 = v 2 = g 2 4M 2 W 4 GeV 2 M Pl 38 GeV 2 >no symmetry in the standard model (SM) protects the Higgs mass >µ H 2 always a singlet under phase transformations > natural explanation would be that SM is replaced by another theory at the TeV scale: µ 2 ~ (heavier scale) 2 new particles H t t H >these theories could be: >SUSY: protecting the Higgs mass by a symmetry >Composite Higgs: the Higgs is not elementary > Large/warped extra dimensions: gravity is strong at electroweak scale Clemens Lange - Diboson resonances searches at CMS 3

4 Composite Higgs? [ t >the Higgs could be nonfundamental >instead: bound state of a new strong interaction >e.g. size of 8 m ~ Fermi scale (0 GeV)! light Higgs like a pion from a new sector >solves hierarchy problem, and brings along new heavy particles/states >heavy partners of SM particles decay to lighter ones (W, Z, H, top, ) H t H Clemens Lange - Diboson resonances searches at CMS 4

5 Large extra dimensions? Eric Williams >another attempt to solve the hierarchy problem >SM fields are confined to fourdimensional membrane, gravity propagates in additional dimensions >effectively, change power law of gravity from /r 2 to /r 2+N, where N = number of extra dimensions >this only applies to particles with r N - smaller things have more possibilities to move > large, because of size mm to ~/TeV >proposed by Arkani-Hamed, Dimopoulos, and Dvali (ADD) gravity Planck-brane bulk gravity can propagate through bulk TeV-brane Clemens Lange - Diboson resonances searches at CMS 5

6 Warped extra dimensions? Eric Williams >often referred to as Randall- Sundrum (RS) models >warping causes energy scale at one end of the extra dimension to be much larger than at the other end >SM models reside on TeV-brane (in RS models) >bulk graviton models allow SM particles into 5D-bulk >overlap of 5-D profiles at TeV-brane (and Higgs) determine particle masses >additionally, if distance between two branes is not fixed, additional fluctuations can occur gravity Planck-brane RS model bulk gravity can propagate through bulk bulk Bulk model TeV-brane Clemens Lange - Diboson resonances searches at CMS 6

7 How do we observe these models at the LHC? >should be able to observe excitations/ resonances/fluctuations q b >composite Higgs: electroweak composite vector resonances H b! mostly spin (W, Z )! decay to pairs of W, Z, H W 0 W >Randall-Sundrum: Kaluza-Klein excitations of gravitons + radion fluctuations >gravitons (spin-2):! RS: decay predominantly to leptons q 0 g l q! bulk: decay to pairs of W, Z! ADD: broader excess from many narrow-spaced resonances W q >radions (spin-0):! only used for signal modelling here X W >focus here on narrow resonances (width < detector resolution), mass 600 GeV g l Clemens Lange - Diboson resonances searches at CMS 7

8 What about the diphoton resonance? >neutral resonance could be graviton or radion as in diboson searches >resonance cannot directly couple to photons loop of charged particles (e.g. W, top,?) in decay (and production?) >there must be more than just a di-photon resonance >searches presented in this talk constrain what physics models this potential resonance could be Clemens Lange - Diboson resonances searches at CMS 8

9 Reconstructing heavy resonances >bosons will be very energetic collimated decay products >need to develop dedicated reconstruction methods >hadronic decays of bosons:! boson-tagging! exploiting substructure of jets >leptonic decays:! special isolation for dileptonic decays! dedicated reconstruction algorithms for high-pt leptons! new tau-identification algorithms focus here on Run-2 developments and analyses Clemens Lange - Diboson resonances searches at CMS 9

10 Hadronic boson identification JHEP 2 (204) 07 >at CMS use anti-kt jet algorithm with R = 0.4 >already for resonances of TeV a significant fraction of cases where the boson decay is contained in a single jet >increase jet size to R = 0.8 to contain full decay within fat jet R = p Reconstruction efficiency Merged jet efficiency single CA R=0.8 jet R (W,jet) < 0. Resolved jets efficiency two AK R=0.5 jets R (q,jet ) < 0. i j W boson p T 8 TeV CMS Simulation (GeV) R qq 2 M V p V T back of the envelope calculation: for a resonance of mass TeV the bosons from the decay will have p T ~0.4 TeV ΔR Clemens Lange - Diboson resonances searches at CMS

11 CMS particle flow reconstruction >tracking detectors and calorimeters contained in magnetic field >particle flow algorithm makes use of sub-detectors with best resolution (both spatial and energy) >actual particles enter jet clustering Clemens Lange - Diboson resonances searches at CMS

12 Jet pruning CMS-PAS-HIG4-008 >we know the masses of W, Z and Higgs very well can use them as constraints >however, large number of particles in jet rather bad resolution >jet pruning (generally grooming) removes soft and large angle radiation arbitrary units 0.2 CMS Simulation SM Higgs, m = 600 GeV ungroomed jet mass W+Jets, MadGraph+Pythia6 ungroomed jet mass >strategy: 0.! recluster jet using Cambridge-Aachen (CA) jet algorithm? pruned jet mass Clemens Lange - Diboson resonances searches at CMS 2

13 Reminder: jet clustering algorithms JHEP 0804:063,2008 >kt-algorithms: sequential clustering >examine four-vector inputs pairwise and construct jets hierarchically >anti-kt: preferentially merge constituents with high pt with respect to their nearest neighbours first >Cambridge-Aachen: no ptweighting, merge based on spatial separation only undoing clustering yields subjets Clemens Lange - Diboson resonances searches at CMS 3

14 Jet pruning CMS-PAS-EXO5-002 >we know the masses of W, Z and Higgs very well can use them as constraints >however, large number of particles in jet rather bad resolution >jet pruning (generally grooming) removes soft and large angle radiation >strategy: Events / 5.00 GeV CMS Preliminary CMS Data W (G (2 TeV) WW (MADGRAPH)) Bulk Z (G (2 TeV) ZZ(MADGRAPH)) Bulk W (W' (2 TeV) QCD PYTHIA8 2.6 fb WZ (MADGRAPH)) (3 TeV)! recluster jet using Cambridge-Aachen (CA) jet algorithm! soft : min(p i T,p j T )/ p T < R ij >m orig /p orig! large angle : T, orig = unpruned CA jet >cut on mass window (~± GeV) Data MC Pruned mass [GeV] Clemens Lange - Diboson resonances searches at CMS 4

15 N-subjettiness JHEP 3:05,20 >for boson-tagging: want to quantify how 2-subjetty a jet is Boosted W Jet, R = 0.6 > to what extent is energy flow aligned along 2 momentum directions (N=2)? N = d 0 X normalisation k 2 p T,k min( R,k,.8 R 2,k,..., R N,k ) sum over particles η low values of τn compatibility with the hypothesis of N axes 2.2 (a) Boosted W Jet, R = 0.6 φ minimise distance to candidate subjets (b) Boosted QCD Jet, R = axes axis W-jet QCD-jet φ.6.4 φ η η (c) (b) (d) Clemens Lange - Diboson resonances searches at CMS 5

16 N-subjettiness ratio CMS-PAS-EXO5-002 >bare τn has very little discrimination power >take ratio τ2/τ instead >mind: rather complicated variable, difficult to model need to validate in data >clean sample of W-jets: top-antitop quark pairs used for calibration Events / ( 0.04 ) 350 CMS CMS Data tt Preliminary Single Top W+jets WprimeTeV x fb VV (3 TeV) MC Stat Events / CMS Preliminary CMS Data G Bulk G Bulk (2 TeV) (2 TeV) W' (2 TeV) QCD PYTHIA8 65 GeV < M P < 5 GeV 2.6 fb (3 TeV) WW (MADGRAPH) ZZ(MADGRAPH) WZ (MADGRAPH) Data / MC τ 2 /τ Data MC τ Clemens Lange - Diboson resonances searches at CMS 6

17 Higgs bb tagging EXO4-009 CMS DP-205/038 >Higgs has higher mass than W/Z bosons τ2/τ less important, exploit b-jet content instead >two different strategies: Arbitrary scale CMS Simulation q/g MADGRAPH+PYTHIA t Wb qq'b H bb H WW* 4q W qq' Z qq CA pruned R=0.8 8 TeV! identify b-subjets! tag fat jet >currently, both show comparable performance >50% lower mis-tagging rate than W-/Z-tagging >dedicated Higgs-tagger available soon Jet mass m j (GeV) H WW qqqq tagging is done using τ4/τ2 ratio (cf. τ2/τ for W/Z) Clemens Lange - Diboson resonances searches at CMS 7

18 Higgs ττ tagging CMS-PAS-EXO5-008 >τ-lepton can decay hadronically and leptonically τ H >need to take into account potential overlap between the two τ-leptons π ν τ! remove tracks/particles entering other isolation cone μ h ν >discrimination against q-/g-jets: MVA-based isolation! sum reconstructed particle energies in various cones around τ decay products >neutrinos in decay cannot be reconstructed missing energy! ττ-reconstruction using templates from Monte Carlo simulation (SVfit) currently only 8 TeV results Events / GeV b-tagged ν untagged CMS Preliminary 9.7 fb (8 TeV) 35 Drell-Yan + jets tt W + jets Single top Diboson QCD multijets Signal 30 (M =.5 TeV, X Observed Λ R =) M(τ,τ) [GeV] Clemens Lange - Diboson resonances searches at CMS 8

19 Lepton (muon + electron) reconstruction CMS DP-203/003 >two isolation issues:! radiation from highly energetic leptons spoils isolation! leptons spoil each other s isolation >employ dedicated high-pt algorithms to preserve high efficiency >loosen selection criteria one of the leptons in Z ll decays >leptonic W-decay: need to recover z-component of neutrino! use W-mass constraint for reconstruction Efficiency Scale Factor High energy electron ID (HEEP) CMS Preliminary, Barrel, E >35 GeV T s = 8 TeV, L dt = 9.6 fb DATA (BG subtracted) DY (MC) E T (GeV) Clemens Lange - Diboson resonances searches at CMS 9

20 Strategy/event selection for VV analyses trigger VV qqqq analysis VW qqlν analysis VZ qqll analysis HT trigger (800 GeV) or jet+groomed mass single lepton trigger (e/µ p T > 5/45 GeV) lepton(s) HEEP e/high-pt µ special iso/id for 2 nd lepton V-jet V boson candidate(s) X anti-kt R=0.8, pt > 200 GeV, exploit substructure τ2/τ, use groomed mass Δη <.3 reconstruct leptonic V, pt > 200 GeV use mass window additional cuts on separation of bosons in Δɸ and ΔR reconstruct X using both reconstructed vector bosons search for bump in mvv distribution X W ` W q q Clemens Lange - Diboson resonances searches at CMS 20

21 Dijet (VV) analysis CMS-PAS-EXO5-002 >trigger at ~0% efficiency at mjj > TeV! apply cut on reconstructed dijet system >define different τ2/τ regions:! high purity to suppress background! low purity to recover signal efficiency at high masses >split W and Z samples based on pruned jet mass (65-85, 85-5 GeV) >still dominated by QCD multi-jet events >difficult to obtain sufficient MC simulation statistics >need a data-driven approach >exponentially falling spectrum: use fit function Events / 0.05 Data MC CMS Preliminary CMS Data G Bulk G Bulk (2 TeV) WW (MADGRAPH) (2 TeV) ZZ(MADGRAPH) W' (2 TeV) WZ (MADGRAPH) QCD PYTHIA8 65 GeV < M P < 5 GeV HP LP 2.6 fb (3 TeV) τ Clemens Lange - Diboson resonances searches at CMS 2

22 VV background estimation CMS-PAS-EXO5-002 >naively, fitting the m JJ spectrum could swallow signal >also, need to avoid claiming false discovery (in particular in tail) >fit function: Events / 94.7 GeV CMS Preliminary CMS data 2 par. background fit G(2 TeV) WW (σ = 0.04 pb) WW, low-purity η < 2.4, p T M jj > TeV, η 2.6 fb (3 TeV) > 200 GeV <.3 jj or 2 parameters 3 parameters >number of free parameters determined by F-test:! check if quality of fit improves by > % confidence level! if not, stick with current fit function >extensive bias tests conducted >combined signal+background fit performed Data-Fit σ Dijet invariant mass [GeV] very similar background estimation strategy as for diphoton resonance search Clemens Lange - Diboson resonances searches at CMS 22

23 Intermezzo: Zɣ search overview CMS-PAS-EXO6-09 >recently published Z ll + ɣ search >inspired by ɣɣ excess >same photon ID as ɣɣ search, dilepton ID as in ZV search, fit background > limited by statistics, no significant excess Events / ( 20 GeV ) 2 CMS Preliminary muon channel 2.7 fb (3 TeV) Data Fit Uncertainty Events / ( 20 GeV ) CMS Preliminary electron channel 2.7 fb (3 TeV) Data Fit Uncertainty (data-fit)/σ stat M(µ + µ γ) [GeV] (data-fit)/σ stat Clemens Lange - Diboson resonances searches at CMS + - M(e e γ) [GeV] 23

24 VW/VZ analysis overview CMS-PAS-B2G6-004 >for 205 data, two separate analyses performed:! low mass : GeV! high mass : -4 TeV! VZ analysis not yet public >difference low vs. high mass:! lower boost can use isolated lepton triggers with 27 GeV thresholds >requiring an isolated lepton suppresses QCD multi-jet background significantly >dominant backgrounds: Events / ( 20 ) Data / MC CMS Preliminary CMS Data VV Single Top WprimeTeV x fb W+jets tt (3 TeV) MC Stat AK8 pt (GeV)! Drell-Yan/W+Jets! top-antitop quark production >can estimate individual background components from sidebands Clemens Lange - Diboson resonances searches at CMS 24

25 VW analysis background estimation CMS-PAS-B2G6-004 CMS-PAS-EXO5-002 >statistics in MC simulated samples still limited >furthermore, analysis performed in extreme phase space >use pruned mass sidebands (40-65 GeV, 3560 GeV) to exploit correlation between pruned jet mass and resonance mass! Higgs mass region kept blind >determine ratio of simulated to data distributions in sideband >extrapolate to signal region using transfer function (based on simulation) >method accounts for data-mc differences in shape and normalisation Pruned jet mass (GeV) Clemens Lange - Diboson resonances searches at CMS Events / ( 5 GeV ) σ data Data-Fit Events / ( 0 GeV ) σ data Data-Fit 4 2 CMS Preliminary CMS signal region WW enriched CMS Data µν WW/WZ Single Top WZ enriched CMS Data eν 3 Preliminary WW/WZ Single Top G Bulk M G =2 TeV ( 0) W+jets tt 2.2 fb (3 TeV) Uncertainty High-Purity Higgs 2.2 fb (3 TeV) W+jets (GeV) tt Uncertainty High-Purity, WW enriched M WV 25

26 Intermezzo: ɣɣ vs. Zɣ vs. WW >limits for narrow resonances! caveat: slightly different models used > minimal upward fluctuations? BR(A Zγ) [fb] 95% CL UL on σ CMS Preliminary Zɣ W = 0.04% 2.7 fb (3 TeV) Observed Expected ± σ Expected ± 2σ CMS-PAS-EXO5-004 CMS-PAS-EXO6-09 CMS-PAS-B2G Resonance Mass [GeV] WW)(pb) Bulk 2 CMS Preliminary WW 2.3 fb (3 TeV) Asympt. CL Expected S Asympt. CL Expected ± s.d. S Asympt. CL Expected ± 2 s.d. S σ BR, k = 0.5 TH GBulk WW Asympt. CL Observed S ɣɣ σ 95% x BR(G -2 W lν (GeV) M G Clemens Lange - Diboson resonances searches at CMS 26

27 VH analysis overview CMS-PAS-B2G6-003 >205 data: H bb, leptonic W/Z decays! W lν! Z ll! Z νν >categorise in single and double subjet b-tag categories > same background estimation method as for VW search Events / 5.0 GeV X Vh (ll,lν,νν)bb CMS Preliminary 0l, b-tag LSB VV Higgs HSB 2.7 fb Data V+jets Top, ST VV, VH Bkg. unc. (3 TeV) Events / 0.0 GeV Z νν, b-tag 2 X Vh (ll,lν,νν)bb CMS Preliminary 0l, b-tag 2.7 fb (3 TeV) Data V+jets Top, ST VV, VH Bkg. unc. m X =2000 GeV HVT model B 5 Pulls jet pruned mass (GeV) Pulls Clemens Lange - Diboson resonances searches at CMS mvh T (GeV) (GeV) mvh T 27

28 Signal modelling and uncertainties CMS-PAS-B2G6-003 >depending on spin of new particles, polarisation of bosons different >Bulk graviton (spin-2) and W /Z (spin) models primarily couple to longitudinal components of W/Z >analytical description of signal shapes based on fully simulated benchmark mass points! double-sided Crystal-Ball function! linearly interpolation between benchmark points >signal efficiency up to 5% depending on analysis category >largest uncertainties: Arbitrary units X Vh (ll,lν,νν)bb 0.7 CMS Simulation Preliminary 2µ channel Z µµ, b-tag (GeV) m Vh 3 TeV m X =800 GeV m X =00 GeV m X =200 GeV m X =400 GeV m X =600 GeV m X =800 GeV m X =2000 GeV m X =2500 GeV m X =3000 GeV m X =3500 GeV m X =4000 GeV! background estimation! jet energy and mass scale! boson-tagging Clemens Lange - Diboson resonances searches at CMS 28

29 Model interpretation arxiv: GH GeVL >several different analyses performed >advantageous to use common 0.benchmark models for easier interpretation 0.0 gg >need to know individual couplings tt to bosons 0.00 Bulk ZZ WW hh aa GH GeVL RS ZZ WW hh aa gg tt qq ll nn - 4 rams! individual analysis: e.g. σ(gg G WW) ure V.4: MGr H GeVL! combination: e.g. σ(gg G)! mind also production mechanism Bulk KK-graviton branching fractions. Left: Bulk scenario, assuming elementary t ZZ rk. Right RS scenario. The dashed line represents the individual RS kk-graviton dec b 0. WW s to a pair of light fermions f f, where f represents both light quarks (u, d, s, c, b) or lepto, ). Branching ratios are independent of k parameter. b g X W W q q arios l for third g family WED embedding: l The thick curves considers MGr H GeVL a fully elementa (b) s not a surprise to note that kk-graviton Clemens Lange - branching Diboson resonances ratios searches toat CMS bosons pais (W/Z/H 29 GH GeVL MGr H GeVL Figure (V.5) shows a zoom of kk-graviton branching ratios comparing two distin quark [60] while thin dashed ones we ignores kk-graviton coupling with top quar hh aa gg tt

30 Model tuning >models described before can be tuned by a handful of parameters >bulk graviton:! mass of graviton! coupling constant determining production cross section and width >heavy vector triplet (HVT): BRHV 0 Æ 2 XL -2-3 Model B.07/JHEP09(204)060 heavy vector triplet (HVT) W + W - Zh uu dd g V = 3 ll è nn bb tt è Feynman diagrams GHV 0 Æ 2 phenomenological Lagrangian! describes production and decay of heavy spin resonances Model A! 4 parameters for resonance g V = mass, interaction strength, couplings g V = 2 to bosons g and fermions V = 3! focus here on Model B with enhanced couplings to bosons M Clemens Lange - Diboson 500 resonances searches 2000 at CMS GHV 0 Æ q Model B q 0 W 0 H W g V = 3 g V = 5 g V = 8 b l b 30

31 Putting it all together >currently, larger number of channels has been covered with 8 TeV data >differentiate between final states (number of leptons and jets) >violet analyses interpreted in dark matter scenarios W lν Z ll V qq Z νν H qqqq H ττ H bb H ɣɣ W lν 3 TeV 3 TeV Z ll 3 TeV 3 TeV V qq 3 TeV 3 TeV 3 TeV 3 TeV Z νν 3 TeV 3 TeV H qqqq H ττ H bb 3 TeV 3 TeV 3 TeV H ɣɣ >several analyses repeated and improved w.r.t. 8 TeV (considering mx > TeV) >several more to come this year Clemens Lange - Diboson resonances searches at CMS 3

32 8 vs. 3 TeV >While 3 TeV has opened up new energy regime, integrated luminosity recorded in 205 significantly below the one of ratios of LHC parton luminosities: 3 TeV / 8 TeV WJS203! 20 fb vs. ~3 fb >LHC is hadron collider - s energy available in collision >need to consider parton luminosities luminosity ratio gg_ Σqq qg >exceed 202 reach with 205 data already at -2 TeV resonance mass 0 00 M X (GeV) MSTW2008NLO [website] >nevertheless, worthwhile combining results Clemens Lange - Diboson resonances searches at CMS 32

33 Combination of diboson analyses CMS-PAS-B2G6-007 >example here: V combination in HVT model B >seven 8 TeV analyses, three at 3 TeV >how to combine upper cross section limits from two different s? (pb) CMS Preliminary 9.7 fb (8 TeV) (pb) CMS Preliminary fb (3 TeV) BR V' WV/VH Asympt. CL S Asympt. CL Asympt. CL HVT B S S (g =3) V Obs. Exp. ± σ Exp. ± 2σ BR V' WV/VH Asympt. CL S Asympt. CL Asympt. CL HVT B S S (g =3) V Obs. Exp. ± σ Exp. ± 2σ σ 95% σ 95% -2 lllv llqq lvqq lvbb qqqq qqbb(4q) qqττ -2 lvqq llbb/lvbb/vvbb qqqq M V' (TeV) M V' (TeV) Clemens Lange - Diboson resonances searches at CMS 33

34 Combination of diboson analyses CMS-PAS-B2G6-007 >convert cross section limits into signal strength limits >8+3 TeV limits comparable at lower masses, 3 TeV dominates high mass > lower masses: leptonic analyses, higher masses: hadronic final states σ 95% /σ theory 2 CMS Preliminary fb (3 TeV) fb lllv (8 TeV) qqbb(4q) (8 TeV) llqq (8 TeV) qqττ (8 TeV) lvqq (8 TeV) lvqq (3 TeV) lvbb (8 TeV) llbb/lvbb/vvbb (3 TeV) qqqq (8 TeV) qqqq (3 TeV) (8 TeV) σ 95% /σ theory 2 CMS Preliminary fb (3 TeV) fb Asympt. CL S (8 TeV) Obs.(solid)/ Exp.(dashed) HVT B (g =3) V Asympt. CL S Asympt. CL Asympt. CL HVT B S S (g =3) V Obs. Exp. ± Exp. ± σ 2σ 8 TeV 3 TeV 8+3 TeV M V' (TeV) M V' (TeV) Clemens Lange - Diboson resonances searches at CMS 34

35 Combination of diboson analyses CMS-PAS-B2G6-007 >can translate observed limits into exclusion contours in the HVT couplings space >additional input to theorists for model building V g 2 cf /g coupling to fermions CMS Preliminary B fb (3 TeV) fb (8 TeV).5 TeV 2 TeV 3 TeV Γ th M > 7% σ exp M coupling to bosons g c V H Clemens Lange - Diboson resonances searches at CMS 35

36 Summary >discovery of a diboson resonance might solve hierarchy problem >however, currently no sign of new physics >3 TeV results already exceed 8 TeV ones > expect another boost with 206 data Clemens Lange - Diboson resonances searches at CMS 36

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38 W-tagging calibration >cutting on τ2/τ-ratio need to know efficiency of cut in data and simulation >select at generator level clean W-events and those that do not match > perform simultaneous fit Events / ( 5 GeV ) fb CMS at Preliminary s = 3TeV tt VV single Top W+jets data W e/µ ν HP Events / ( 5 GeV ) fb CMS at Preliminary s = 3TeV tt VV single Top W+jets data W e/µ ν HP pruned jet mass (GeV) pruned jet mass (GeV) Clemens Lange - Diboson resonances searches at CMS 38

39 boson-tagging efficiencies Tagger BR(W/Z/H xx) efficiency W/Z qq 70 % 35 %.2 % H bb 57 % 35 % 0.5 % H WW qqqq % 35 %.5 % mistag rate (q-/g-jets) H ττ 6 % 35 % 0.03 % Clemens Lange - Diboson resonances searches at CMS 39

40 Zɣ search limits CMS-PAS-EXO6-09 >recently published Z ll + ɣ search 0.04% width 5.4% width BR(A Zγ) [fb] CMS Preliminary W = 0.04% 2.7 fb (3 TeV) Observed Expected ± σ Expected ± 2σ BR(A Zγ) [fb] CMS Preliminary W = 5.6% 2.7 fb (3 TeV) Observed Expected ± σ Expected ± 2σ 95% CL UL on σ % CL UL on σ Resonance Mass [GeV] Resonance Mass [GeV] Clemens Lange - Diboson resonances searches at CMS 40