BESS Model Resonance in the pp W + W tt + X Channel at LHC M. Gintner, I. Melo, B. Trpišová University of Žilina CERN, Nov 1, 2006

Outline BESS Model Vector Resonance ρ Cross sections for pp → WWtt + X (CompHEP calculation) reconstruction (CompHEP, Pythia, Atlfast, Root)

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

Large Hadron Collider: pp at 14 TeV pp ―› jj WWpp ―› jj tt pp ―› ρ tt ―› WW tt pp ―› ρ tt ―› tt tt pp ―› WW pp ―› tt

39/8 diagrams in the dominant gg channel No-resonance background ρ ρ ρ

Cuts: 700-3Γρ < m WW < Γρ (GeV) p T (t) > 100 GeV, |y(t)| < 2 σ(gg) = 10.2 fb ―› 1.0 fb No resonance background: σ(gg) = fb 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 g t 1,2 = g v b 2 /4g π =M ρ /2vg v

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 Athena 9.0.3

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

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

number of events/32 GeV Lum = 100 fb events ρ: Mρ=1000 GeV Γρ=26 GeV

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

Appendix

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

Total width Γ tot of ρ

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