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Phenomenology of New Vector Resonances from SEWSB at Future e+e- Colliders

IEP SAS, Kosice, May 13, 2005. Phenomenology of New Vector Resonances from SEWSB at Future e+e- Colliders. Ivan Melo. M. Gintner, I. Melo, B. Trpisova (University of Zilina). Outline. Motivation for new vector ( ρ ) resonances: Strong EW Symmetry Breaking (SEWSB)

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Phenomenology of New Vector Resonances from SEWSB at Future e+e- Colliders

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  1. IEP SAS, Kosice, May 13, 2005 Phenomenology of New Vector Resonances from SEWSB at Future e+e- Colliders Ivan Melo M. Gintner, I. Melo, B. Trpisova (University of Zilina)

  2. Outline • Motivation for new vector (ρ) resonances: Strong EW Symmetry Breaking (SEWSB) • Vector resonance model • ρ signals in e+ e- →ννtt,e+ e-→ tt • ρ signal in pp → ρtt→ WWtt

  3. Higgs boson Higgs boson

  4. EWSB: SU(2)L x U(1)Y→ U(1)Q Weakly interacting models: - SUSY - Little Higgs Strongly interacting models: - Technicolor

  5. 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

  6. LEP: e+e-, Ecm = 209 GeV Tevatron: pp, Ecm = 2 000 GeV, L = 1 fb-1 LHC: pp, Ecm = 14 000 GeV, L = 100 fb-1 ILC: e+e-, Ecm = 1 000 GeV, L = 200 fb-1 CLIC: e+e-, Ecm = 3-5 000 GeV, L = 200 fb-1

  7. WL WL→ WL WLWLWL → t tt t → t t L = i gπMρ/v (π- ∂μπ+ - π+ ∂μπ-)ρ0μ + gV t γμ t ρ0μ+ gA t γμ γ5 t ρ0μ

  8. International Linear Collider: e+e- at 1 TeV ee ―› ρtt ―›WW tt ee ―› ρtt ―›tt tt ee ―› WW ee ―› tt ee ―› ννWW ee ―›ννtt Large Hadron Collider: pp at 14 TeV pp ―› ρtt ―›WW tt pp ―› ρtt ―›tt tt pp ―› WW pp ―› tt pp ―› jj WW pp ―› jj tt

  9. Chiral effective Lagrangian SU(2)L x SU(2)R global, SU(2)L x U(1)Y local L = Lkin - v2 Tr [ Aμ Aμ] -a v2 /4 Tr[(ωμ + i g''ρμ . τ/2 )2] - ψL u+u+ M ψR – h.c. + ψL i γμ (∂μ + Wμ+ i g’/6 Yμ) ψL + ψR i γμ (∂μ + Yμ+ i g’/6 Yμ) ψR +b1ψL i γμ (u+∂μ – u+ρμ+ u+ i g’/6 Yμ) u ψL + b2ψRPb i γμ (u ∂μ – u ρμ+ u i g’/6 Yμ) u+PbψR + λ1ψL i γμ u+ Aμγ5 u ψL +λ2ψR Pλ i γμ u Aμγ5 u+PλψR + κ2ψR Pκ i γμ u (ωμ + ρμ) u+ PκψR BESS Our model Minimal modelStandard Model with Higgs replaced with ρ

  10. A simple Lagrangian L = i gπ Mρ/v (π- ∂μπ+ - π+ ∂μπ- )ρ0μ + gV t γμ t ρ0μ+ gA t γμ γ5 t ρ0μ Chiral effective Lagrangian L = - v2 Tr [ Aμ Aμ] -a v2 /4 Tr[(ωμ + i g''ρμ . τ/2 )2] + b1 IbL + b2 IbR + ... gπ= Mρ /(2 v g'') gV ≈ g'' b2 /4 = gA (b1 = 0) Mρ≈ √a v g''/2

  11. Unitarity constraints WLWL → WLWL , WLWL → t t,t t → t t gπ ≤ 1.75 (Mρ= 700 GeV) gV ≤ 1.7 (Mρ= 700 GeV) Low energy constraints g’’ ≥ 10 → gπ ≤ 0.2 Mρ(TeV) |b2 – λ2| ≤ 0.04 → gV ≈ g’’ b2 / 4

  12. Subset of fusion diagrams + approximations (Pythia) Full calculation of 66 diagrams at tree level (CompHEP)

  13. Pythia vs CompHEP ρ (M = 700 GeV, Γ = 12.5 GeV, g’’ = 20, b2 = 0.08) Before cuts √s (GeV) 800 1000 1500 Pythia (fb) 0.35 0.95 3.27 CompHEP (fb) 0.66 1.16 3.33

  14. Backgrounds (Pythia) e+e- → tt γ e+e- → e+e- tt σ(0.8 TeV) = 300.3 + 1.3 fb → 0.13 fb(0.20 fb) σ(1.0 TeV) = 204.9 + 2.4 fb → 0.035 fb (0.16 fb)

  15. ≈ S/√B

  16. e- e+→ t t ρ different from Higgs ! ρ (M= 700 GeV, b2=0.08, g’’=20)

  17. Search at Hadron Colliders Tevatron: p + p ―› t + t σS= 1.2 fb σB = 8 306 fb LHC: p + p ―› t + t σS = 22.7 fb σB = 752 000 fb

  18. Search at LHC: pp → W W t t g g ―› WW tt 39 diagrams u u ―› WW tt 131 diagrams d d ―› WW tt 131 diagrams Signal: σ(gg) = 10.2 fb ―› 1.0 fb Cuts: 650 < mWW < 750 GeV pT > 100 GeV |y| < 2 R > 5 Background: σ(gg) = 10.6 fb ―› 0.6 fb σ(uu) = 2.4 fb ―› 0.1 fb

  19. Conclusions • New strong ρ-resonance model • ρ in e+e- → ννttR values up to 8 • e+e- → tt – sensitive probe of mt physics, Lscan = 1 fb-1 (preliminary) • pp → W W t t R > 5 (preliminary !)

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