1. Signatures of a new vector resonance from strongly interacting electroweak symmetry breaking M. Gintner, I. Melo, B. Trpišová University of Žilina Exotics meeting, CERN Oct 10, 2007

2. Outline BESS Model Vector Resonance ρ pp processes sensitive to ρ, cross sections (CompHEP calculation) Reconstruction of pp → W + W - t t + X and pp → b b t t + X (CompHEP, Pythia, Atlfast, Root)

3. Chiral SB in QCD SU(2) L x SU(2) R → SU(2) V, vev ~ 90 MeV EWSB SU(2) L x SU(2) R → SU(2) V, vev ~ 246 GeV

4. t t t π = W L are BESS coupling constants is the SU(2) L coupling constant v is EW scale (246 GeV) 1,2 R.Casalbuoni et al. Phys.Lett. B155 (1985) 95; M.Gintner, I.Melo, B.Trpisova, Acta Phys. Slovaca, 56(2006)1,b,b,b

5. BESS (Breaking EW Symmetry Strongly) Model SU(2) L x SU(2) R global, SU(2) L x U(1) Y local L = L kin + L non.lin. σ model - a v 2 /4 Tr[(ω μ + i g v ρ μ. τ/2 ) 2 ] + L mass + L SM (W,Z) + b 1 ψ L i γ μ (u + ∂ μ – u + i g v ρ μ. τ/2 + u + i g’/6 Y μ ) u ψ L + b 2 ψ R P b i γ μ (u ∂ μ – u i g v ρ μ. τ/2 + u i g’/6 Y μ ) u + P b ψ R + λ 1 ψ L i γ μ u + A μ γ 5 u ψ L + λ 2 ψ R P b i γ μ u A μ γ 5 u + P b ψ R Standard Model with Higgs replaced with ρ Our model ω μ = [u + (∂ μ + i g’/2 Y μ τ 3 )u + u(∂ μ + i g W μ. τ/2)u + ]/2 A μ = [u + (∂ μ + i g’/2 Y μ τ 3 )u - u(∂ μ + i g W μ. τ/2)u + ]/2 u = exp( i π. τ /2v) ψ L = (t L,b L ) P b = diag(1,p) M ρ ≈ √a v g v /2 v ≈ 246 GeV … EW scale R.Casalbuoni et al. Phys.Lett. B155 (1985) 95; M.Gintner, I.Melo, B.Trpisova, Acta Phys. Slovaca, 56(2006)1

6. Large Hadron Collider: pp at 14 TeV pp ―› jj WW pp ―› jj tt pp ―› ρ tt ―› WW tt pp ―› ρ tt ―› tt tt pp ―› ρtt ―› bb tt pp ―› ρbb ―› bb tt pp ―› WW pp ―› tt M ρ = 1 000 GeV Γ ρ = 42.3 GeV

7. CompHEP: pp → bb → tt + X σ S = 174 fb Background G G → t t 3 diagrams σ B = 25 605 fb Signal 6 diagrams

8. CompHEP: pp → bb → W + W - + X uu → W + W - dd → W + W - 4 diagrams Signal 4 diagrams σ S = 15.4 fb σ B = 450 fb σ S → 14.0 fb σ B → 100 fb m WW pT W Background

9. CompHEP: pp → ttρ 0 + X → bb t t + X Signal 8 diagrams σ S = 3.7 fb σ B = 17 fb QCD background 35 diagrams QCD Signal m bb pT b QCD bottom Signal bottom

10. CompHEP: pp → bbρ 0 + X → bb t t + X Signal 8 diagrams σ S = 134 fb σ B = 833 fb QCD background 35 diagrams QCD Signal m tt pT t QCD top Signal top Γ ρ =127 GeV σ = 337 fb

11. CompHEP: pp → tbρ + + X → bb t t + X Signal 8 diagrams σ S = 86 fb σ B = 332 fb QCD background 35 diagrams m tb Signal top QCD top QCD Signal pT q bottom

12. Cuts: 700-3Γρ < m WW < 700 +3Γρ (GeV) p T (t) > 100 GeV, |y(t)| < 2 σ S = 1.0 fb Irreducible background M WW (GeV) CompHEP results: pp → W + W - t t + X ρ: Mρ=700 GeV, Γρ=4 GeV, b 2 =0.08, g v =10 39 diagrams 8 diagrams σ B = 0.037 fb

13. 39/8 diagrams in the dominant gg channel No-resonance background ρ ρ ρ CompHEP results: pp → W W t t + X (continued)

14. pp → bb → tt + X pp → bb → W + W - + X pp → ttρ 0 + X → bb t t + X pp → bbρ 0 + X → bb t t + X pp → tbρ + + X → bb t t + X pp → ρ 0 tt → W W t t + X σ S = 174 σ B = 25 605 σ S = 14 σ B = 100 σ S = 3.7 σ B = 17 σ S = 134 σ B = 833 σ S = 86 σ B = 332 σ S = 1 σ B = 0.037 Cross sections in the peak region in fb

15. pp → W W t t + X l jjbjjbjj reconstruction (CompHEP, Pythia, Atlfast, Root) One charged lepton channel: Cuts: electron > 30 GeV muon > 20 GeV jets > 25 GeV Reconstruction criterion 40% of events mass of the W: GeV b-tagging efficiency 50% of

16. number of events/32 GeV Lum = 100 fb -1 12.8 events ρ: Mρ=1000 GeV Γρ=26 GeV CompHEP Reconstruction

17. pp → ρ 0 tt → bb t t + X → bb lν l b jjb (43.5%) reconstruction (CompHEP, Pythia, Atlfast, Root) N S =0.8 N B =8 L = 100 fb -1 Cuts: of e > 30 GeV j > 25 GeV μ > 20 GeV L = 100 fb -1 GeV

18. pp → bb → tt + X pp → bb → W + W - + X pp → ttρ 0 + X → bb t t + X pp → bbρ 0 + X → bb t t + X pp → tbρ + + X → bb t t + X pp → ρ 0 tt → W W t t + X σ S = 174 σ B = 25 605 σ S = 14 σ B = 100 σ S = 3.7 σ B = 17 σ S = 134 σ B = 833 σ S = 86 σ B = 332 σ S = 1 σ B = 0.037 Conclusions Thanks to Jonathan Ferland for his great help with reconstruction !

19. Backup

20. number of events/17 GeV 39 diagrams 8 diagrams Lum=100/fb 12.2 events Lum=100/fb 2.4 events Distribution in invariant mass of WW pair (ρ →WW) ρ: Mρ=700 GeV, Γρ=4 GeV, b 2 =0.08, g v =10 P z (ν) chosen correctly in 61.5 % of events

21. 8 diagrams 39 diagrams number of events/0.6 GeV number of events/2.5 GeV Mass of the W boson Mass of the top quark Lum=100/fb 2.4 events 12.2 events

22. versus 8 diagrams 1. Can we improve WWtt reconstruction ? 2. L = 100/fb 2.4 events 8 diagrams

23. Total width Γ tot of ρ

24. EWSB: SU(2) L x U(1) Y → U(1) Q Weakly interacting models: - SUSY - SM (light) Higgs Strongly interacting models: - Technicolor A new strong vector resonance ρ as an isospin triplet ( ) → BESS