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BESS Model Resonance in the pp W + W tt + X Channel at LHC

CERN, Nov 1, 2006. BESS Model Resonance in the pp W + W tt + X Channel at LHC. M. Gintner, I. Melo, B. Trpi šová University of Žilina. Outline BESS Model Vector Resonance ρ Cross sections for pp →WWtt + X (CompHEP calculation) reconstruction

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BESS Model Resonance in the pp W + W tt + X Channel at LHC

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

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

  3. t t t 1,2 1,2 1,2 π = WL are BESS coupling constants is the SU(2)L coupling constant v is EW scale (246 GeV) R.Casalbuoni et al. Phys.Lett. B155 (1985) 95;M.Gintner, I.Melo, B.Trpisova, Acta Phys. Slovaca, 56(2006)1

  4. 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

  5. 39/8 diagrams in the dominant gg channel ρ No-resonance background ρ ρ

  6. CompHEP results: pp → W W t t + X ρ: Mρ=700 GeV, Γρ=4 GeV, b2=0.08, gv=10 39 diagrams 8 diagrams MWW(GeV) gπ=Mρ/2vgv gt1,2= gv b2/4 σ(gg) = 10.2 fb ―› 1.0 fb Cuts: 700-3Γρ < mWW < 700 +3Γρ (GeV) pT (t) > 100 GeV, |y(t)| < 2 No resonance background: σ(gg) = 0.037 fb

  7. l jjbjjbjj reconstruction (CompHEP, Pythia, Atlfast, Root) Athena 9.0.3 One charged lepton channel: 40% of events electron > 30 GeV muon > 20 GeV of Cuts: GeV mass of the W: jets > 25 GeV 50% b-tagging efficiency Reconstruction criterion

  8. 8 diagrams 39 diagrams Lum=100/fb Lum=100/fb 12.2 events 2.4 events number of events/17 GeV Distribution in invariant mass of WW pair (ρ →WW) ρ: Mρ=700 GeV, Γρ=4 GeV, b2=0.08, gv=10 Pz(ν) chosen correctly in 61.5 % of events number of events/17 GeV

  9. 39 diagrams 8 diagrams Mass of the W boson Lum=100/fb Lum=100/fb 12.2 events 2.4 events number of events/0.6 GeV number of events/0.6 GeV Mass of the top quark Lum=100/fb Lum=100/fb 12.2 events 2.4 events number of events/2.5 GeV number of events/2.5 GeV

  10. ρ: Mρ=1000 GeV Γρ=26 GeV Lum = 100 fb-1 12.8 events number of events/32 GeV

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

  12. Appendix

  13. BESS (Breaking EW Symmetry Strongly) Model 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 gvρμ . τ/2 )2] + Lmass+ LSM(W,Z) +b1ψL i γμ (u+∂μ – u+i gvρμ . τ/2+ u+ i g’/6 Yμ) u ψL + b2ψRPb i γμ (u ∂μ – u i gvρμ . τ/2 + u i g’/6 Yμ) u+PbψR + λ1ψL i γμ u+ Aμγ5 u ψL +λ2ψR Pb i γμ u Aμγ5 u+PbψR Our model Standard Model with Higgs replaced with ρ ωμ = [u+(∂μ + i g’/2 Yμτ3)u + u(∂μ+ i g Wμ . τ/2)u+]/2 Aμ = [u+(∂μ + i g’/2 Yμτ3)u - u(∂μ+ i g Wμ . τ/2)u+]/2 u = exp(i π . τ/2v) ψL = (tL,bL) Pb = diag(1,p) Mρ≈ √a v gv/2 v ≈ 246 GeV … EW scale

  14. Total width Γtot of ρ

  15. 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 resonanceρas an isospin triplet ( ) → BESS

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