Search for heavy resonances at the LHC. Sabine Crépé-Renaudin on behalf of the ATLAS and CMS collaborations

Transcription

1 Search for heavy resonances at the LHC Sabine Crépé-Renaudin on behalf of the ATLAS and CMS collaborations

2 Why looking beyond Standard Model? Standard model is in wonderful agreement with experiments However The following are missing: Gravity Dark matter Neutrinos mass And there are unanswered questions: Why 3 generations and fermion mass hierarchy? Why matter-antimatter asymmetry? Why is the Higgs light? Why is gravity so weak? FFP14, Search for heavy resonances at the LHC Sabine Crépé-Renaudin 17 juillet

3 Some new ideas beyond Standard Model Extra dimensions [address hierarchy problems] Large and flat (ADD), TeV scale and flat (UED), TeV scale and warped (RS1, Bulk RS model) Compactified extra dimensions Kaluza-Klein excitations of particles If sqrt(s)>m D (fundamental higher dimensional Planck scale) black holes, strings New strong sector [address electroweak symmetry breaking, naturalness, fermion generations] Technicolor Little Higgs Compositeness Excited quarks and leptons, leptoquarks Grand unification [address gauge unification or restore L/R symmetry] Larger symmetry groups that breaks to SM gauge group + additional ones (E 6, Minimal Models, EGM) Heavy gauge bosons FFP14, Search for heavy resonances at the LHC Sabine Crépé-Renaudin 17 juillet

4 Heavy resonances! Most of these models predict new heavy particles with short lifetime that appear as resonances Breit-Wigner Parton luminosity Bump over smooth background + SM background Relatively easy way to look for direct signs of new physics at hadron collider FFP14, Search for heavy resonances at the LHC Sabine Crépé-Renaudin 17 juillet

5 ATLAS, CMS and the run1 of the LHC Wonderful tools to explore the unknown Will focus on newest 8 TeV results of ATLAS and CMS with full 2012 run 1 luminosity ~ 20 fb -1 FFP14, Search for heavy resonances at the LHC Sabine Crépé-Renaudin 17 juillet

6 Strategy and Outline Look for as many signatures as possible in the most model-independent way probe highest available energies but also lower ones for low cross-section production Challenges: uncertainties evaluation at high energy, boosted topologies, Search for bump over SM distributions for each final state In case no significant deviation from SM seen : limit set to all available models predicting resonance decay in the studied channel Impossible to do justice to all these nice results: only s-channel resonances and most recent analyses shown Di-leptons Di-quarks Mixed Di-bosons ll lν jj tt tb γj Vj VV γγ Vγ HH Extra dimensions ADD,RS,UED X X X X X X Heavy Gauge boson (GUT, SSM,L/R) X X X X X Technicolor X X X Compositeness X X X X Composite Higgs X X Dark matter X FFP14, Search for heavy resonances at the LHC Sabine Crépé-Renaudin 17 juillet

7 Lepton final states Signatures 8 TeV Reference Presented ee, μμ 20.3, 20.5 fb , 20.6 fb-1 arxiv: CMS-PAS-EXO yes ττ 19.5 fb -1 ATLAS-CONF no l + E miss 20.3 fb -1 ATLAS-CONF T 20 fb -1 CMS-PAS-EXO yes m(ee)=1.541 TeV m T (µ+met)=2.082 TeV FFP14, Search for heavy resonances at the LHC Sabine Crépé-Renaudin 17 juillet

8 Z g ll Di-lepton : ee,µµ arxiv: CMS-PAS-EXO ATLAS: ee CMS: ee ATLAS: µµ CMS: µµ Selection: 2 isolated leptons (efficiency 40-70%) ATLAS/CMS: E T (e) > 40,30/35 GeV, p T (µ) > 25/45 GeV; Opposite charge requested only for muon channel Good resolution in ee (~1%), good fake rejection in µµ Main backgrounds: Drell-Yan, diboson, top and jets (fake rate from data) FFP14, Search for heavy resonances at the LHC Sabine Crépé-Renaudin 17 juillet

9 Z g ll Di-lepton : ee,µµ SSM, E 6, Z* RS G* coupling arxiv: CMS-PAS-EXO SSM, E 6 Min Walking Technicolor: spin1 resonance interaction vs bare axial-vector mass ATLAS: Numerous models tested: SSM Z, E 6 Z ψ Z χ, Z* from (Z*,W*) doublet, RS graviton, minimal walking Technicolor, Quantum Black Holes Simulated signal from Drell-Yan reweighted to theoretical resonance shape Likelihood scan over whole m ll range CMS: SSM Z, Z ψ Likelihood on Z over Z cross-sections ratio on a restricted mass range Main systematic: PDF No excess limits in the TeV range: Z SSM > 2.96 TeV (CMS) 2.90 TeV (ATLAS) FFP14, Search for heavy resonances at the LHC Sabine Crépé-Renaudin 17 juillet

10 W g lν Di-leptons: e/µ+ν W g eν ATLAS-CONF CMS-PAS-EXO W g eν W g µν W g µν Selection: 1 isolated lepton + E T miss (efficiency 60-90%) ATLAS: E T (e) > 125 GeV, p T (µ) > 45 GeV, E T miss > 125(e), 45(µ) CMS: E T (e) > 100 GeV, p T (µ) > 45 GeV, ΔΦ(l,ν )> 0.8π, 0.4< p T /E T miss <1.5 Main backgrounds: SM W, Z, top, diboson, multi-jets (from data) Main uncertainties: PDF increases quickly at high masses, MC stat FFP14, Search for heavy resonances at the LHC Sabine Crépé-Renaudin 17 juillet

11 W g lν Di-leptons: e/µ+ν ATLAS-CONF CMS-PAS-EXO W W* split UED: R = 5 th dim radius µ = fermion bulk mass ATLAS: SSM W (no interference) and excited chiral W* (phase space restricted to m(lν) > 0,4 x m W ) (also interaction producing dark matter particle pair) SSM & split UED CMS: SSM W (with interference), W R, W 2 KK of split universal extra-dimension No excess limits in the TeV range: W SSM > 3.2 TeV (CMS and ATLAS) FFP14, Search for heavy resonances at the LHC Sabine Crépé-Renaudin 17 juillet

12 di-quarks final states Signatures 8 TeV Reference Presented tt tb jj bb 14.3 fb -1 ATLAS-CONF fb -1 B2G fb fb -1 ATLAS EXOT CMS JHEP 05 (2014) fb fb fb -1 ATLAS arxiv: CMS-PAS-EXOT CMS-PAS-EXO no Yes Yes m(jj)=5.15 TeV m(tb)=3.252 TeV FFP14, Search for heavy resonances at the LHC Sabine Crépé-Renaudin 17 juillet

13 W g tb di-quarks: tb complementary to leptonic searches allows to test models with enhanced coupling to 3 rd generation, all ν R mass hyp. ATLAS: W g tb g Wbb g qq bb 1 large top jet + 1 b-jet + anti isolated lepton veto top tagging: trimmed anti-k T jet R=1.0, p T >350 GeV d 12 > 40 GeV, τ 32 < <τ 12 <0.9 Backgrounds: mainly multijets, tt (data fit) CMS: W g tb g Wbb g lνbb ATLAS EXOT CMS JHEP 05 (2014) isolated e/µ + 2 jets + E t miss > 20 GeV pt(top) > 85 GeV, pt(j1+j2)>140 GeV 130 < M(t) < 210 GeV Backgrounds: tt, W/Z+jets, single top WW tt: top pt reweighted from cross-section analysis t g eνb t g µνb t g qqb FFP14, Search for heavy resonances at the LHC Sabine Crépé-Renaudin 17 juillet

14 Interlude: large jets and V/top tagging heavy particles boosted particles (top, W, Z) lepton no more isolated, jets close from each other novel tools developed isolation cone radius getting smaller with p T, remove 2nd lepton in cone large jet and cleaning/grooming: soft component and pile-up cleaning V or top-tagging: use of jet substructure k T splitting scale: d 12 = p 2 T weighted distance between the 2 subjets from the last step of k T clustering algorithm (hardest objects last) N-subjetiness τ N : sum of p T weighted minimum distance of jet components to center of subjets when N subjets reconstructed with k T d 12 τ 32 τ 21 FFP14, Search for heavy resonances at the LHC Sabine Crépé-Renaudin 17 juillet

15 Models di-quarks: tb W R, W L with same quark coupling as SM W CMS takes into account the interference in the W L case Systematics: b and top tagging ATLAS EXOT CMS JHEP 05 (2014) 108 ATLAS all hadronic W L : pb W R : pb W L W R W R CMS semi-leptonic W L no interference > 2.05 TeV W L interference > 1.84 TeV W R > 2.05 TeV W R > 2.13 TeV (mν R > mw R) (hyp: couplings a ud =a tb ) FFP14, Search for heavy resonances at the LHC Sabine Crépé-Renaudin 17 juillet

16 X g jj Trigger Selection di-quarks: jj ATLAS: single jet prescaled allow to be sensitive to small mass (+delayed 100 Hz increased stat at m jj = TeV) CMS: Particle Flow jets with H T >650 GeV and m jj >750 GeV ATLAS: 2 R=0.6 leading jets (pt>50 GeV, η <2.8) y lead -y sublead < 1.2, m jj > 250 GeV CMS: 2 wide jets to include gluon radiation add all jets if within ΔR<1.1 of the 2 leading R=0.5 jets leading jets: pt>30 GeV, η <2.5; wide jets Δη jj <1.3, m jj >890 GeV ATLAS arxiv: CMS-PAS-EXOT CMS-PAS-EXO Background: data fit di-quarks: bb/bg 1 b-jet FFP14, Search for heavy resonances at the LHC Sabine Crépé-Renaudin 17 juillet

17 X g jj di-quarks: jj Systematics: JES, JER, fit, luminosity, PDF model independent results Gaussian/BreitWigner + gluon radiation + parton luminosity qq,qg,gg and specific models: string, E6,q*,s8, V, W*, RS G, QBH CMS: narrow jet resonance, specific models derived, b-jets analysis ATLAS: full template shape used, specific models fully generated, sensitivity to low mass region qq PDF ATLAS arxiv: CMS-PAS-EXOT CMS-PAS-EXO b-jet analysis No excess: limits on q* > 4.09/3.5 TeV, W > 2.45/2.29 TeV (ATLAS/CMS), QBH > 5.82 TeV (ATLAS), RS G*>1.58 (CMS) CMS b-jet analysis: Z excluded in [ ], RS G* in [ ], b* in [ ] TeV FFP14, Search for heavy resonances at the LHC Sabine Crépé-Renaudin 17 juillet

18 Mixed final states Signatures 8 TeV Reference Presented jγ 20.3 fb -1 ATLAS arxiv: fb -1 CMS arxiv: Yes jw/jz 19.7 fb -1 CMS arxiv: Yes* * see diboson final state m(jγ)=2.93 TeV FFP14, Search for heavy resonances at the LHC Sabine Crépé-Renaudin 17 juillet

19 q* γ +jet γ+j q* QBH ATLAS arxiv: CMS arxiv: q* q* γ +jet: s-channel process isotropic distribution Main backgrounds: SM γ +jet, multi-jets mainly t-channel process peaks in forward region parameterized with Selection: 1 isolated γ in barrel and 1 back to back jet γ with p T > 170/125 GeV (CMS/ATLAS) ΔR(jet,γ)>0.5 (CMS) and p T > 170/125 GeV, M(jet,γ)> 560/426 GeV (CMS/ATLAS) Acceptance: Δη(jet,γ) < 2.0/1.6 (CMS/ATLAS) back to back topology: Δφ(jet,γ) > 1.5 (CMS) FFP14, Search for heavy resonances at the LHC Sabine Crépé-Renaudin 17 juillet

20 q* γ +jet γ+j q* ATLAS arxiv: CMS arxiv: q* Gaussian QBH q* Models tested ATLAS & CMS: spin ½ excited quarks of first generation; compositeness scale Λ = M q*, all coupling to SM partners = f ATLAS: ADD non-thermal quantum black holes (QBH) Generic gaussian shape sources like topological pions No excess limits: q* > 3.2 TeV (CMS) q* > 3.5 TeV (ATLAS) QBH > 4.6 TeV (ATLAS) FFP14, Search for heavy resonances at the LHC Sabine Crépé-Renaudin 17 juillet

21 Vector boson final states Signatures 8 TeV Reference Presented VV all jets 19.7 fb -1 arxiv: yes VV l+jets WZ lν ll 19.7 fb fb -1 CMS arxiv: ATLAS-COM-CONF fb -1 ATLAS arxiv fb -1 CMS arxiv: Vγ 20.3 fb -1 ATLAS EXOT backup yes yes M(µµJ) = TeV M(WZ) = TeV FFP14, Search for heavy resonances at the LHC Sabine Crépé-Renaudin 17 juillet

22 X VV, qv Diboson resonance: fully hadronic arxiv: Final states: qv or VV (V=W or Z) qq ( ) from V highly boosted in a single V jet V tagging! Selection: 2 jets (0.8 Cambridge-Aachen): p T >30GeV, η <2.5, Δη(j,j) <1.3 V tagging: Pruning: discard soft or large ΔR proto-jets ; Jet tagged if 70 < m j _pruned < 100 GeV N Subjettiness: τ 21 <0.5 High Purity, 0.5 < τ 21 < 0.75 Low Purity region Main backgrounds: multi-jets modelled by an empirical distribution: FFP14, Search for heavy resonances at the LHC Sabine Crépé-Renaudin 17 juillet

23 X VV, qv Diboson resonance: fully hadronic Main uncertainties: signal modelling V-tagging, PDF, JER Models: excited quark q*, RS graviton G RS (k/m pl =0.1 width ~1%), RS bulk graviton G bulk (k/m pl = width ~1%), W with SM V-A coupling arxiv: q*g qw q*g qz W g WZ G RS g WZ G RS g ZZ G bulk g WW No excess limits for q*: 3.2 TeV (qw), 2.9 TeV (qz); W : 1.7 TeV (WZ) and G RS 1.3 TeV (WW) FFP14, Search for heavy resonances at the LHC Sabine Crépé-Renaudin 17 juillet

24 X VV Diboson resonance: semi-leptonic Final states: lνqq ( ) (CMS) or llqq ( ) (l = e, µ) (ATLAS+CMS) with ll and qq ( ) highly boosted lepton isolation & V tagging! ATLAS: isolated leptons and anti-k T jet (j) or 1.2 CA for merge jets (J) allow to be sensitive at low masses also splitting and filtering for J (p T >100 GeV) modified lepton isolation criteria if 2 leptons close (no more calo iso and 2 nd lepton p T substracted) 70 < m j/j < 110 GeV, 66 < m ll < 116 GeV CMS: isolated leptons and 0.8 Cambridge Aachen jets Pruning: W-tag if 65 < m j _pruned < 105 GeV, Z-tag if 70 < m j _pruned < 110 GeV n-subjettiness ratio, same purity categories as fully hadronic channel CMS arxiv: ATLAS-COM-CONF m(lljj) m(llj) (merge) m(zz) m(ww) FFP14, Search for heavy resonances at the LHC Sabine Crépé-Renaudin 17 juillet

25 X VV Diboson resonance: semi-leptonic Main backgrounds: V+jets (normalization from data), VV, tt Main uncertainties: V tagging (CMS), Z+jets (ATLAS) Models: bulk RS graviton G (first KK excitation) + EGM W (ATLAS) CMS arxiv: ATLAS-COM-CONF EGM W g ZW RS G*g ZZ ATLAS: EGM W > TeV RS bulk G* > 740 (540) GeV for k/m Pl =1.0 (0.5) CMS: Model independent limits on event number provided with reconstructed V efficiency Limits combined with fully hadronic channel RS G*g ZZ RS G*g WW FFP14, Search for heavy resonances at the LHC Sabine Crépé-Renaudin 17 juillet

26 X WZ WZ lνl l (l, l = e, µ) Diboson resonance: WZ all leptonic ATLAS arxiv CMS arxiv: Full leptonic channel better sensitivity at low mass: lepton trigger, smaller background and higher mass resolution Selection: ATLAS: exactly 3 charged leptons and E T miss mz=m(l + l - ); m W =m(l+ν) Δy(W,Z) < signal regions: Low mass: m W < 250GeV, Δφ(l,E miss T ) >1.5 High mass: m W > 250GeV, Δφ(l,E miss t ) < 1.5 CMS: at least 3 leptons and E miss T mz=m(l + l - ); m W =m(l+ν) m(lll) >120 GeV, ΔR(l Z,l W )> 0.3 Sliding search windows in L T =Σp T (l) and m(wz) for each m X Main backgrounds: WZ, ZZ, Zϒ, tt+w/z from MC FFP14, Search for heavy resonances at the LHC Sabine Crépé-Renaudin 17 juillet

27 X WZ Diboson resonance: WZ all leptonic Main uncertainties: PDF and normalisation/factorisation scale for background ATLAS arxiv CMS arxiv: Models Extended gauge model (EGM) with a spin-1 W boson (narrow resonance) ATLAS Sequential Standard Model (SSM) (also limit on W -WZ coupling) CMS Phenomenological Lagrangian (parameters for coupling to fermions and bosons) for Heavy Vector Triplet (HVT) (model A = SM gauge group extension; model B Composite Higgs ATLAS No excess m W (EGM) > 1.5 TeV (ATLAS); m W (SSM) excluded in [ ] GeV FFP14, Search for heavy resonances at the LHC Sabine Crépé-Renaudin 17 juillet

28 Higgs final states Signatures 8 TeV Reference Presented HH g bbbb 19.5 fb -1 ATLAS-CONF yes HH g γγbb γγ 20.3 fb -1 ATLAS arxiv: fb -1 CMS-PAS-HIG fb -1 ATLAS-CONF fb -1 CMS-PAS-HIG no* no *see W. Mader talk M(bbbb) = 834 GeV FFP14, Search for heavy resonances at the LHC Sabine Crépé-Renaudin 17 juillet

29 Diboson resonance: HH bbbb ATLAS-CONF Selection: 2 nearby (ΔR<1.5) tagged bb pair tt veto, p T (jet)>40gev, dijets near Higgs mass Elliptical signal region Main backgrounds: multi-jets (from data), tt (MC) Main uncertainties: background shape and normalisation, JES and JER, b-tagging efficiency Model: bulk RS graviton G* (first KK excitation) Br(G*->HH)~7% No excess limit for k/m pl =1.0: 590 GeV < m G* < 710 GeV FFP14, Search for heavy resonances at the LHC Sabine Crépé-Renaudin 17 juillet

30 Conclusion ATLAS and CMS collaborations explored the TeV scale in a wide range of final states beautiful results, no new physics... yet! Only few analysis presented here and still many to come for complete results see: Collaboration summary graphs in the backup slides ATLAS web page: CMS web page: and Next 13 TeV LHC run: is new physics just round the corner? FFP14, Search for heavy resonances at the LHC Sabine Crépé-Renaudin 17 juillet

31 Conclusion ATLAS and CMS collaborations explored the TeV scale in a wide range of final states beautiful results, no new physics... yet! Only few analysis presented here and still many to come for complete results see: Collaboration summary graphs in the backup slides ATLAS web page: CMS web page: and Next 13 TeV LHC run: is new physics just round the corner? Next run will allow to probe higher masses + parton luminosity x [10-100] Probing lower mass range still to remain sensitive to low couplings Expected run 2 integrated luminosity ~ 300 fb -1 and analysis in constant progress: New techniques to deal with high energy, high luminosity and boosted topologies (lepton id and reconstruction, jet substructure) New models to test, channel combination and analysis more model-independent 8 TeV limits FFP14, Search for heavy resonances at the LHC Sabine Crépé-Renaudin 17 juillet

32 Going further FFP14, Search for heavy resonances at the LHC Sabine Crépé-Renaudin 17 juillet

33 Summary of ATLAS exotics results FFP14, Search for heavy resonances at the LHC Sabine Crépé-Renaudin 17 juillet

34 Summary of CMS exotics results FFP14, Search for heavy resonances at the LHC Sabine Crépé-Renaudin 17 juillet

35 Summary of CMS exotics results FFP14, Search for heavy resonances at the LHC Sabine Crépé-Renaudin 17 juillet

36 X Vγ Diboson resonance: Vγ all leptonic Wγ lνγ, Zγ llγ Selection: 1(2) isolated electron/muon p T > 25 GeV, 1 isolated photon E T > 40 GeV, ΔR(lγ) > 0.7 Wγ: E T miss > 35 GeV, p T (lν) > 40 GeV; Zγ: 65<m(ll)<115 GeV Main backgrounds: SM Zγ, Wγ, Z+jets,W+jets, γ+jets; normalization from likelihood fit Main uncertainties: photon/lepton ID and reco ATLAS EXOT Model spin 0 Φ (phenomenological model: composite particle, pseudo-goldstone boson); Φ Zγ No excess: exclusion Spin 0 Φ Zγ [ ] GeV FFP14, Search for heavy resonances at the LHC Sabine Crépé-Renaudin 17 juillet