Search for a New Vector Resonance in the pp WWtt+X Channel at LHC September 2006 Search for a New Vector Resonance in the pp WWtt+X Channel at LHC M. Gintner, I. Melo, B. Trpišová University of Žilina

Motivation An alternative to the SM Higgs boson: Strong Electroweak Symmetry Breaking A new strong vector resonance as an isospin triplet ( )

The Model Modified BESS model -- the only non SM particle Respects the symmetries of the SM Higgs sector: local, global > 10 < 0.1 … coupling constants of the original BESS ~ ~ … coupling constant GeV … electroweak scale

Analysis of pp For the dominant gg channel: cross-sections and statistical significance CompHEP reconstruction CompHEP – events generation Pythia – decay and hadronization Atlfast – detector effects and reconstruction of the jets ROOT, C++ -- event reconstruction

39(8) diagrams in the dominant gg channel No resonance background ρ ρ ρ

CompHEP Results Cuts: GeV 0.96 fb … 39 diagrams ρ: Mρ=700 GeV, Γρ=4 GeV, b2=0.08, g =10 “ Cuts: GeV 0.96 fb … 39 diagrams 0.037 fb … No 39 diagrams R ~ ~ 46 … 39 diagrams

l jjbjjbjj Reconstruction One charged lepton channel: 40% of events Cuts: of electron > 30 GeV muon > 20 GeV jets > 25 GeV mass of the W: GeV b-tagging efficiency 50% Reconstruction criterion

Invariant mass of the WW pair … Mass of the ρ-resonance number of events/17 GeV 8 diagrams 39 diagrams Lum=100/fb 2.4 events 12.2 events number of events/17 GeV

8 diagrams 39 diagrams Mass of the W boson Mass of the top quark 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 2.4 events 12.2 events number of events/2.5 GeV number of events/2.5 GeV

Conclusions For the resonance with GeV, g”=10, =0.08: I. in the final state – maximum values of R at around 100 II. reconstruction The top quark and the W reconstruction O.K. The ρ reconstruction – 40% of events fall into the ρ peak need to improve the reconstruction algorithm III. Future work -- -- much larger cross-section compared to , i.e. larger numbers of events

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