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.

Παρουσίαση με θέμα: "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."— Μεταγράφημα παρουσίασης:

1 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)

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

3 Higgs boson Higgs boson

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

6 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

7 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

8 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

9 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

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

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

13 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) Pythia (fb) CompHEP (fb)

14 Backgrounds (Pythia) e+e- → e+e- tt e+e- → tt γ
σ(0.8 TeV) = fb → 0.13 fb (0.20 fb) σ(1.0 TeV) = fb → fb (0.16 fb)

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19 e- e+ → t t different from Higgs !

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