Searches for heavy resonances with the ATLAS detector

Transcription

1 Searches for heavy resonances with the ATLAS detector Oliver Endner Institute of Physics, JGU Mainz November st, 03 O.Endner (JGU Mainz) PASCOS 03 November st, 03 / 9

2 Motivation Motivation Highest energies at the LHC make it possible to look for New Phenomena With data taken in 0 in pp collisions at s = 8 TeV ATLAS looked in: Dilepton (Z, spin- graviton G*) Diboson WZ l ν l l (W, techni-mesons) Diboson ZZ lljj/llj (G*) Lepton+Jet (quantum black hole) Photon+Jet (q*, quantum black hole) Dijet (q*) Testing different theory models: Compositeness, sequential standard model, E6 grand unified theory, extended gauge model, low scale technicolor, Randall-Sundrum, ADD O.Endner (JGU Mainz) PASCOS 03 November st, 03 / 9

3 Dilepton(e/µ-channel) High mass di-electron event ATLAS-CONF mee =.5 TeV, pt =0.59/0.58 TeV O.Endner (JGU Mainz) PASCOS 03 November st, 03 3 / 9

4 Dilepton(e/µ-channel) Dilepton(e/µ-channel) Models: Z (SSM,E6), G*(RS) Signature: l + l (with l=e,µ) two electrons η <.47 E T > 40/30 GeV two muons η <.4 E T > 5 GeV Spectrum: mass lepton-pair Normalized to Z-peak Backgrounds: From simulation: Drell-Yan, diboson and t t Data-driven: W+jet and dijet Signals: From LO simulation Events Observed / Expected Z ee Search L dt = 0 fb s = 8 TeV Data 0 Z/γ* tt Dijet & W+Jets Diboson Z (500 GeV) Z (500 GeV) m ee [GeV] Events Observed / Expected Z µµ Search L dt = 0 fb s = 8 TeV Data 0 Z/γ* tt Diboson Z (500 GeV) Z (500 GeV) m µµ [GeV] ATLAS-CONF O.Endner (JGU Mainz) PASCOS 03 November st, 03 4 / 9

5 Dilepton(e/µ-channel) Dilepton(e/µ-channel) σ B [pb] Systematics(dominant): 3 4 Drell-Yan background (PDF) Data-driven background ee, µµ: L dt = 0 fb s = 8 TeV Z ll Expected limit Expected ± σ Expected ± σ Observed limit Z SSM Z χ Z ψ σ B [pb] 95% CL mass limits κ/m Pl = 0. for G* 3 4 ee, µµ: L dt = 0 fb s = 8 TeV G* ll Expected limit Expected ± σ Expected ± σ Observed limit k/m Pl = 0. k/m Pl = 0.05 k/m Pl = 0.03 k/m Pl = 0.0 ATLAS-CONF M Z [TeV] M G* [TeV] Z Ψ Z χ Z ee Z µµ Z G* Obs. limit[tev] Exp. limit[tev] O.Endner (JGU Mainz) PASCOS 03 November st, 03 5 / 9

6 Dilepton(τ-channel) Dilepton(τ-channel) Models: Z (SSM) Signature: τ + τ two τ in η <.5 with >50 GeV p lead T Spectrum: Total transverse mass mt tot Backgrounds: Drell-Yan(MC) Multijet(data-driven) Systematics(dominant): Multijet estimation and τ energy scale Limits:.90/.80 TeV (obs/exp) 95% CL Events obs. / exp. 4 3 L dt = 9.5 fb s = 8 TeV Data 0 Z/γ* τ τ Multijet W/Z+jets tt+single top Diboson Z (750) τ τ tot miss m T (τ had vis, τ had vis, E T ) [GeV] σ(pp Z ) BR(Z ττ) [pb] 3 ATLAS Preliminary L dt = 9.5 fb s = 8 TeV τ had τ had channel Expected limit Expected ± σ Expected ± σ Observed limit Z SSM Z SSM th. uncert [GeV] m Z ATLAS-CONF O.Endner (JGU Mainz) PASCOS 03 November st, 03 6 / 9

7 Lepton+Jet Lepton+Jet Models: QBH (ADD) Signature: l+j (l=e,µ) e/µ: η <.4; p T > 30 GeV jet: η <.5; p T > 30 GeV Spectrum: inv. lepton-jet mass Backgrounds: Vector boson+jet (MC) Diboson (MC) t t and single t (MC) Multijet (data-driven) Events / 0. TeV (a) ATLAS s = 8 TeV e+jet L dt = 0.3 fb Data 0 W+jets Z+jets top quark Diboson Multijet QBH (4 TeV) QBH (5 TeV) Invariant Mass (e,jet) [TeV] Events / 0. TeV (b) ATLAS s = 8 TeV µ+jet L dt = 0.3 fb Data 0 W+jets Z+jets top quark Diboson Multijet QBH (4 TeV) QBH (5 TeV) Invariant Mass (µ,jet) [TeV] arxiv:3:006 O.Endner (JGU Mainz) PASCOS 03 November st, 03 7 / 9

8 Lepton+Jet Lepton+Jet Systematics(dominant): Extrapolation of background PDF Assumptions: n=6, M th = M D 95% CL limits Limit on σ BF: 0.8 fb above 3.5 TeV Limit on QBH mass: m > 5.3 TeV [fb] BF qq qq σ 95% CL upper limit Expected Expected ± σ Expected ± σ Observed QBH prediction ATLAS L dt = 0.3 fb s = 8 TeV arxiv:3: M th [TeV] O.Endner (JGU Mainz) PASCOS 03 November st, 03 8 / 9

9 Diboson(WZ,ZZ) High mass WZ event m WZ =. TeV ATLAS-CONF O.Endner (JGU Mainz) PASCOS 03 November st, 03 9 / 9

10 Diboson(WZ,ZZ) Diboson(WZ-channel) Models: W (extended gauge model),technimesons(lstc) Signature: lνl l (l,l =e,µ) l l : same flavour opposite sign l l mass within 0 GeV to Z e: η <.47; p T >5 GeV µ: η <.4; p T >5 GeV Spectrum: mass of WZ system Divided in four channels: eνee, µνee, eνµµ, µνµµ Backgrounds: Diboson and Zγ(MC) Z+jets, t t and Wt(data-driven) Events / 0 GeV s=8 TeV, Ldt=3.0 fb Data ZZ Zγ W (m=600 GeV) WZ ll+jets Wγ inclusive channel W (m=800 GeV) ρ (m=400 GeV) ρ (m=600 GeV) T T σ stat.+sys. Events / 0 GeV s=8 TeV, Ldt=3.0 fb Data ZZ Zγ W (m=600 GeV) WZ ll+jets Wγ inclusive channel W (m=800 GeV) ρ (m=400 GeV) ρ (m=600 GeV) T T σ stat.+sys. ATLAS-CONF p W [GeV] T Z p [GeV] T O.Endner (JGU Mainz) PASCOS 03 November st, 03 / 9

11 Diboson(WZ,ZZ) Diboson(WZ-channel) Systematics(dominant) WZ sample (σ + higher-order) Method: frequentist log-likelihood ratio Using signal templates from crystal ball fit Limit(95% CL): m W >80/300 GeV (obs/exp) Events / 40 GeV s = 8 TeV Ldt = 3.0 fb Z + γ ZZ ll + jets WZ 0 Data Total Error σ BR(WZ) (pb) Expected 95% CL Limit ± ± σ σ W EGM Cross Section Observed Limit s = 8 TeV Ldt = 3.0 fb ATLAS-CONF [GeV] M WZ W Mass [GeV] O.Endner (JGU Mainz) PASCOS 03 November st, 03 / 9

12 Diboson(WZ,ZZ) Diboson(ZZ-channel) Models: G* (RS bulk) Signature: lljj/llj (l=e,µ) e: η <.47; E T > 5 GeV µ: η <.4; p T > 5 GeV 66 GeV<m ll <6 GeV Spectrum: mass of llqq system Consider merged dijet (high m jjll ) Background: From fit to data ( x) f (x) = p 0 p x p +p 3 ln(x) with x = m/ s Events / 50 GeV s = 8 TeV, Ldt = 7. fb Z ee + Z µµ Resolved Selection Data Z+jets WW/WZ/ZZ tt W+jets mg* = 800 GeV σ G* m(lljj) [GeV] Events / 50 GeV 3 s = 8 TeV, Ldt = 7. fb Z ee + Z µµ Merged Selection Data Z+jets WW/WZ/ZZ tt W+jets mg* = 400 GeV σ G* m(llj) [GeV] ATLAS-CONF-050 O.Endner (JGU Mainz) PASCOS 03 November st, 03 / 9

13 Diboson(WZ,ZZ) Diboson(ZZ-channel) Systematics(dominant): Fit function Compare fit with data: BumpHunter algorithm 95% CL limit Combine selections: m < TeV (resolved)+m > TeV (merged) Bayesian limit Assumptions: κ/m Pl =.0 m>850/870 GeV (obs/exp) Events Significance Resolved Selection Data Background s = 8 TeV Ldt = 7. fb 3 3 m(lljj) [GeV] σ(pp G*) BR( G* ZZ ) [pb] RS Graviton, κ/m Planck =.0 Observed 95% Upper Limit Expected 95% Upper Limit ± σ ± σ s = 8 TeV, Ldt = 7. fb [GeV] m G* ATLAS-CONF-050 O.Endner (JGU Mainz) PASCOS 03 November st, 03 3 / 9

14 Photon+Jet Photon+Jet Models: q*,qbh,generic Gaussian resonances Signature: γ+jet γ: η <.37; p T > 5 GeV jet: η <.8; p T > 5 GeV Supress Background: η γ η j <.6 Background: Fit to data (f (x)) Search for deviations: BumpHunter algorithm Events 5 4 ATLAS s = 8 TeV L dt = 0.3 fb 3 Significance 0 Data Fit q* (.5 TeV) q* (.5 TeV) q* (3.5 TeV) m γ j [TeV] O.Endner (JGU Mainz) PASCOS 03 November st, 03 4 / 9 arxiv:

15 Photon+Jet Photon+Jet Main Systematics: Fit function Limit on generic Gaussian shaped signal σ BR A ε [fb] ATLAS s = 8 TeV L dt = 0.3 fb 95% CL upper limits: σ G / m G = 5% % 7% 5% 95% CL limits: m QBH >4.6/4.6 TeV (obs/exp) m q* >3.5/3.4 TeV (obs/exp) [fb] BR A ε σ ATLAS s = 8 TeV L dt = 0.3 fb PYTHIA q* prediction 95% CL upper limits: Observed Limit Expected Limit ± σ band Expected Limit ± σ band arxiv: [TeV] m G [TeV] m q* O.Endner (JGU Mainz) PASCOS 03 November st, 03 5 / 9

16 Dijet High mass dijet event ATLAS-CONF-048 mjj = 4.7 TeV, pt =.3/. TeV O.Endner (JGU Mainz) PASCOS 03 November st, 03 6 / 9

17 Dijet Dijet Models: q* Signature: jet+jet invariant mass: m jj > TeV jet: η <.8 Supress background: y y <. Background: Fit to data Search for deviations: BumpHunter algorithm Events Significance 5 Data Background s = 8 TeV L dt = 3.0 fb Reconstructed m jj [GeV] [ data fit ] / fit 4 0 s=8 TeV, L dt = 3.0 fb [ data fit ] / fit q* PYTHIA 8 (500) q* PYTHIA 8 (500) q* PYTHIA 8 (3000) q* PYTHIA 8 (3750) [GeV] Reconstructed m jj ATLAS-CONF-048 O.Endner (JGU Mainz) PASCOS 03 November st, 03 7 / 9

18 Dijet Dijet 95% CL Limit on σ xa [pb] Systematics(dominant): Jet energy scale 95% CL limit 3 4 s = 8 TeV L dt = 3.0 fb / m G σ G [GeV] Mass, m G σ xa [pb] Limit on Gaussian shaped signals Limits (q*): m>3.84/3.70 TeV (obs/exp) 3 3 q* MC Observed 95% CL upper limit Expected 95% CL upper limit 68% and 95% bands L dt = 3.0 fb s = 8 TeV Mass [GeV] ATLAS-CONF-048 O.Endner (JGU Mainz) PASCOS 03 November st, 03 8 / 9

19 Summary Summary Search for heavy resonances in data recorded in 0 at s=8 TeV in five final states was presented: Dilepton Lepton+Jet Diboson (WZ,ZZ) Photon+Jet Dijet No new physics was found, Upper limits have been improved Improvement by up to 30% (wrt 7 TeV) Now most limits in multi-tev region O.Endner (JGU Mainz) PASCOS 03 November st, 03 9 / 9

20 Summary Overview Signature Luminosity Reference l + l (l=e,µ) 0 fb ATLAS-CONF τ + τ ATLAS-CONF l + jet 0 fb arxiv:3:006 WZ 3 fb ATLAS-CONF ZZ 7. fb ATLAS-CONF-050 γ+jet 0 fb arxiv: dijet 3 fb ATLAS-CONF-048 O.Endner (JGU Mainz) PASCOS 03 November st, 03 9 / 9

21 Summary Limits Analysis Model obs. Limit [TeV] exp. Limit [TeV] ll (l=e,µ) Z G* τ τ Z WZ W.8.30 ZZ G* γ+jet q* QBH dijet q* O.Endner (JGU Mainz) PASCOS 03 November st, 03 9 / 9

22 Backup All Limits LQ V' CI Extra dimensions New quarks Other Excit. ferm. Large ED (ADD) : monojet + E T,miss Large ED (ADD) : monophoton + E T,miss Large ED (ADD) : diphoton & dilepton, m γ γ / ll UED : diphoton + E T,miss S /Z ED : dilepton, m ll RS : dilepton, m ll RS : WW resonance, m T,lν lν Bulk RS : ZZ resonance, m lljj RS g tt (BR=0.95) : tt l+jets, m KK tt ADD BH (M TH /M D =3) : SS dimuon, N ch. part. ADD BH (M TH /M D =3) : leptons + jets, Σp T Quantum black hole : dijet, F χ (m jj ) qqqq contact interaction : χ(m ) jj qqll CI : ee & µµ, m ll uutt CI : SS dilepton + jets + E T,miss Z' (SSM) : m ee/µµ Z' (SSM) : m ττ Z' (leptophobic topcolor) : tt l+jets, m tt W' (SSM) : m T,e/µ W' ( tq, g =) : m R tq W' R ( tb, LRSM) : m tb Scalar LQ pair (β=) : kin. vars. in eejj, eνjj Scalar LQ pair (β=) : kin. vars. in µµjj, µνjj Scalar LQ pair (β=) : kin. vars. in ττjj, τνjj th 4 generation : t't' WbWb 4th generation : b'b' SS dilepton + jets + E T,miss Vector-like quark : TT Ht+X Vector-like quark : CC, m lν q Excited quarks : γ-jet resonance, m Excited quarks : dijet resonance, m γ jet jj Excited b quark : W-t resonance, m Wt Excited leptons : l-γ resonance, m lγ Techni-hadrons (LSTC) : dilepton, m ee/µµ Techni-hadrons (LSTC) : WZ resonance (lνll), m WZ Major. neutr. (LRSM, no mixing) : -lep + jets ± Heavy lepton N (type III seesaw) : Z-l resonance, m ±± ±± Zl HL (DY prod., BR(H ll)=) : SS ee (µµ), m L ll Color octet scalar : dijet resonance, m jj Multi-charged particles (DY prod.) : highly ionizing tracks Magnetic monopoles (DY prod.) : highly ionizing tracks ATLAS Exotics Searches* - 95% CL Lower Limits (Status: May 03) L=4.7 fb, 7 TeV [.449] L=4.6 fb, 7 TeV [09.465] L=4.7 fb, 7 TeV [.50] L=4.8 fb, 7 TeV [ ] L=5.0 fb, 7 TeV [09.535] L=0 fb, 8 TeV [ATLAS-CONF-03-07] L=4.7 fb, 7 TeV [08.880] L=7. fb, 8 TeV [ATLAS-CONF-050] L=4.7 fb, 7 TeV [ ] L=.3 fb, 7 TeV [.0080] L=.0 fb, 7 TeV [ ] L=4.7 fb, 7 TeV [.78] L=4.8 fb, 7 TeV [.78] L=5.0 fb, 7 TeV [.50] L=4.3 fb, 8 TeV [ATLAS-CONF-03-05] L=0 fb, 8 TeV [ATLAS-CONF-03-07] L=4.7 fb, 7 TeV [.6604] L=4.3 fb, 8 TeV [ATLAS-CONF-03-05] L=4.7 fb, 7 TeV [ ] L=4.7 fb, 7 TeV [ ] L=4.3 fb, 8 TeV [ATLAS-CONF ] L=.0 fb, 7 TeV [.488] L=.0 fb, 7 TeV [03.37] L=4.7 fb, 7 TeV [ ] L=4.7 fb, 7 TeV [.5468] L=4.3 fb, 8 TeV [ATLAS-CONF-03-05] L=4.3 fb, 8 TeV [ATLAS-CONF-03-08] L=4.6 fb, 7 TeV [ATLAS-CONF-037] L=. fb, 7 TeV [.3580] L=3.0 fb, 8 TeV [ATLAS-CONF-048] L=4.7 fb, 7 TeV [30.583] L=3.0 fb, 8 TeV [ATLAS-CONF-046] L=5.0 fb, 7 TeV [09.535] L=3.0 fb, 8 TeV [ATLAS-CONF-03-05] L=. fb, 7 TeV [03.540] L=5.8 fb, 8 TeV [ATLAS-CONF-03-09] 45 GeV L=4.7 fb, 7 TeV [.5070] L=4.8 fb, 7 TeV [.78] L=4.4 fb, 7 TeV [30.57] L=.0 fb, 7 TeV [07.64] 4.37 TeV M D (δ=).93 TeV M D (δ=) M S (HLZ δ=3, NLO) ATLAS 4.8 TeV Preliminary.40 TeV Compact. scale R 4.7 TeV M KK ~ R.47 TeV Graviton mass (k/m Pl = 0.).3 TeV Graviton mass (k/m Pl = 0.) 850 GeV Graviton mass (k/m Pl =.0) Ldt = ( - 0) fb.07 TeV g mass KK M (δ=6) s = 7, 8 TeV.5 TeV D.5 TeV M D (δ=6) 4. TeV M D (δ=6) 7.6 TeV Λ 3.9 TeV Λ (constructive int.) 3.3 TeV Λ (C=).86 TeV Z' mass.4 TeV Z' mass.8 TeV Z' mass.55 TeV W' mass 430 GeV W' mass.84 TeV W' mass st 660 GeV gen. LQ mass nd 685 GeV gen. LQ mass rd 534 GeV 3 gen. LQ mass 656 GeV t' mass 70 GeV b' mass 790 GeV T mass (isospin doublet). TeV VLQ mass (charge /3, coupling κ qq = ν/m Q ).46 TeV q* mass 3.84 TeV q* mass 870 GeV b* mass (left-handed coupling). TeV l* mass (Λ = m(l*)) 850 GeV ρ T /ω T mass (m(ρ /ω T ) - m(π T ) = M ) T W 90 GeV ρ mass (m(ρ ) = m(π T ) + m W, m(a ) =. m(ρ )) T T T T.5 TeV N mass (m(w ) = TeV) R ± N mass ( V = 0.055, V µ = 0.063, V τ = 0) e ±± 409 GeV HL mass (limit at 398 GeV for µµ).86 TeV Scalar resonance mass 490 GeV mass ( q = 4e) 86 GeV mass *Only a selection of the available mass limits on new states or phenomena shown Mass scale [TeV] O.Endner (JGU Mainz) PASCOS 03 November st, 03 9 / 9

23 Backup Obs. Limit evolution Analysis Model Limit 0 [TeV] Limit 0 [TeV] ll (l=e,µ) Z..86 G*.6.47 τ τ Z WZ W ZZ G*(RS) 0.85 G*(bulk RS) 0.85 γ+jet q* dijet q* O.Endner (JGU Mainz) PASCOS 03 November st, 03 9 / 9

24 Backup Diphoton Search with s = 7 TeV Model: G (RS), M S -scale (ADD) Signature: photons: γ: η <.37, p T >5 GeV Use BumpHunter For κ/m Pl Limits (G): m>.06/.05 TeV (obs/exp) Events/bin 3 3 ATLAS L dt = 4.9 fb Control region 0 data Total Background Reducible Background syst stat (total) syst stat (reducible) RS, k/m Pl = 0., m G =.5 TeV ADD, GRW, M S =.5 TeV s = 7 TeV [pb] σ B(G γγ) ATLAS s = 7 TeV G γγ γγ: Observed limit Expected limit Expected ± σ Expected ± σ k/ M Pl = 0. k/ M Pl = 0.05 k/ M Pl = 0.03 k/ M Pl = 0.0 L dt = 4.9 fb arxiv:.8389 Significance m γγ [GeV] m G [TeV] O.Endner (JGU Mainz) PASCOS 03 November st, 03 9 / 9

25 Backup Systematics Dilepton (e/µ) ATLAS-CONF O.Endner (JGU Mainz) PASCOS 03 November st, 03 9 / 9

26 Backup Systematics Dilepton (τ) ATLAS-CONF O.Endner (JGU Mainz) PASCOS 03 November st, 03 9 / 9

27 Backup Systematics lepton+jet Source Electron+jet Muon+jet % % Lepton reconstruction, scale and resolution Jet reconstruction, scale and resolution Multijet modeling PDF Fit Total arxiv:3:006 O.Endner (JGU Mainz) PASCOS 03 November st, 03 9 / 9

28 Backup Systematics WZ ATLAS-CONF O.Endner (JGU Mainz) PASCOS 03 November st, 03 9 / 9

29 Backup Systematics ZZ Source rel. uncertainty Background fit 5-40% Lepton trigger efficiency % Electron reconstruction/identification efficiency % Muon reconstruction efficiency <% Electron energy scale/resolution % Muon momentum scale/resolution <% JES -3% JER -% JMS -5% PDF % ISR/FSR % Luminosity 3.6% ATLAS-CONF-050 O.Endner (JGU Mainz) PASCOS 03 November st, 03 9 / 9

30 Backup Systematics Photon+jet Source rel. uncertainty Luminosity.8% Photon isolation efficiency.% Trigger efficiency 0.5% Photon identification efficiency.5% Jet energy scale.0.5% Photon energy scale 0.3% Background fit -0% arxiv: O.Endner (JGU Mainz) PASCOS 03 November st, 03 9 / 9

31 Backup Systematics dijet Source rel. uncertainty Jet energy scale 4% Luminosity 3.6% Fit function JER neglible ATLAS-CONF-048 O.Endner (JGU Mainz) PASCOS 03 November st, 03 9 / 9