TAM, Bratislava, Dec 14, 2004 Phenomenology of New Vector Resonances from SEWSB at Future e+e- Colliders Ivan Melo M. Gintner (University of Zilina) I. Melo (University of Zilina)

Outline Motivation for new vector (ρ) resonances: Strong EW Symmetry Breaking (SEWSB) Vector resonance model ρ signals in e+ e- → ννtt, e+ e- → tt

Higgs boson Higgs boson

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

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

WL WL → t t L = i gπ Mρ /v (π- ∂μ π+ - π+ ∂μ π-) ρ0μ + gV t γμ t ρ0μ + gA t γμ γ5 t ρ0μ

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 + b1 ψL i γμ (u+∂μ – u+ ρμ + u+ i g’/6 Yμ) u ψL + b2 ψR Pb i γμ (u ∂μ – u ρμ + u i g’/6 Yμ) u+ Pb ψR + λ1 ψL i γμ u+ Aμ γ5 u ψL + λ2 ψR Pλ i γμ u Aμ γ5 u+ Pλ ψR + κ2 ψR Pκ i γμ u (ωμ + ρμ) u+ Pκ ψR Minimal model Standard Model with Higgs replaced with ρ

Chiral effective Lagrangian A simple Lagrangian L = i gπ Mρ /v (π- ∂μ π+ - π+ ∂μ π- )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

Unitarity constraints WL WL → WL WL , WL WL → 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

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

Pythia vs CompHEP Before cuts √s (GeV) 800 1000 1500 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

Backgrounds (Pythia) e+e- → e+e- tt e+e- → tt γ 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)

e- e+ → t t different from Higgs !

Conclusions New strong ρ-resonance model ρ in e+e- → ννtt, e+e- → tt – sensitive probe of mt physics σ(1 TeV) = 0.16 (0.035) fb, R values up to 8