Vector Resonance from Strong EWSB in pp → WWtt, tttt CERN, Oct 27, 2005 Vector Resonance from Strong EWSB in pp → WWtt, tttt Ivan Melo M. Gintner, I. Melo, B. Trpisova (University of Zilina)

Outline ρtt → tttt + X Motivation for new vector (ρ) resonances: Strong EW Symmetry Breaking (SEWSB) Vector resonance model ρ signal in pp → ρtt → WWtt + X ρtt → tttt + X

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

International Linear Collider: e+e- at 1 TeV ee ―› ρtt ―› WW tt ee ―› ρtt ―› tt tt ee ―› WW ee ―› tt ee ―› νν WW ee ―› νν tt 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

Chiral effective Lagrangian SU(2)L x SU(2)R global, SU(2)L x U(1)Y local L = Lkin + Lnon.lin. σ model - a v2 /4 Tr[(ωμ + i gv ρμ . τ/2 )2] + Lmass + LSM(W,Z) + 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 BESS Our model Standard Model with Higgs replaced with ρ gπ = Mρ /(2 v gv) gt = gv b2 /4 + … Mρ ≈ √a v gv /2 t

Unitarity constraints Low energy constraints gv ≥ 10 → gπ ≤ 0.2 Mρ (TeV) |b2 – λ2| ≤ 0.04 → gt ≈ gv b2 / 4 Unitarity constraints WL WL → WL WL , WL WL → t t, t t → t t gπ ≤ 1.75 (Mρ= 700 GeV) gt ≤ 1.7 (Mρ= 700 GeV)

Partial (Γ―›WW) and total width Γtot of ρ

Search at LHC: pp → W W t t + X J. Leveque et al. ATL-PHYS-2002-019: pp -> Htt -> WWtt MH =[120-240] GeV ρ BRA: pp → ρtt →WWtt σ(WWtt) = σ(ρtt) x BR(ρ->WW) 2) Full calculation: pp → WWtt

pp → W W t t + X (full calculation) 39 diagrams in gg channel No resonance background ρ ρ ρ

CompHEP results: pp → W W t t + X ρ: Mρ=700 GeV, Γρ=4 GeV, b2=0.08, gv=10 SM: MH = 700 GeV ΓH = 184 GeV MWW(GeV) MWW(GeV) σ(gg) = 10.2 fb ―› 1.0 fb σ(gg) = 11.3 fb ―› 0.20 fb No resonance background: σ(gg) = 0.037 fb Cuts: 700-3Γρ < mWW < 700 +3Γρ (GeV) pT > 100 GeV, |y| < 2

Total cross sections for ρtt and WWtt BRA: σ(WWtt) = σ(ρtt) x BR(ρ->WW)

|N(ρ) – N(no res.)| √(N(no res.)) R = ≈ S/√B > 5 BRA Full calc.

tttt vs WWtt BRA BRA

Conclusions New strong ρ-resonance model pp → W W t t + X pp → t t t t + X at LHC R values up to a few 100 (before t,W decays and detector effects) Backgrounds pp → tt, W + jets, Z + jets, … ? Similar work on pp → t t t t + X : T.Han et al, hep-ph/0405055

Search at Hadron Colliders Mρ=700 GeV, Γρ=12.5 GeV 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

pp → ρ t t + X (8 diagrams in gg channel) BRA: σ(WWtt) = σ(ρtt) x BR(ρ->WW)

pp → Htt (SM) : σgg(MH = 100) = 943 fb σgg(MH = 700) = 8.2 fb σuu(MH = 100) = 98 fb σuu(MH = 700) = 0.3 fb