Xinyu Miao Department of Physics Univ. of Arizona 03/30/07 Heavy top partner @ LHC Xinyu Miao Department of Physics Univ. of Arizona 03/30/07 Work in progress with Shufang Su

Outline Large Hadron Collider Hierarchy Problem and Little Hierarchy Problem Left-Right Twin Higgs Model Study of the Heavy Top at the LHC Conclusion

Large Hadron Collider LHC, pp, Ecm=14 TeV

Large Hadron Collider LEP ~.2 TeV Tevtron ~2 TeV LHC ~14TeV

Standard Model Where is the Higgs? 

The Hierarchy Problem Plank Scale ~1034GeV2 t SM Higgs mass~ EW Scale~100GeV

The Little Hierarchy Electroweak Precision Measurement

Twin Higgs model Heavy Top SM Top yL=yR SM Gauge Boson tSM yL=yR tHeavy ~(100GeV)2 SM Gauge Boson Heavy Gauge Boson WHeavy WSM yL=yR Reference: Z. Chacko, Hock-Seng Goh , Roni Harnik JHEP 0601:108,2006

Heavy Particles WH ~3TeV tH ~1TeV  ~300GeV SM Particles

Heavy top tH production

Heavy top tH decay j W tH  b t l  3 b + 1 j + 1 lepton + missing ET

tH → b ϕ± Dominant background tt (one W → lν, one W→ qq), Wjjbb Cuts - Dominant background tt (one W → lν, one W→ qq), Wjjbb Cuts lepton (e or μ) with pT > 30 GeV, |η|<2.5 at least three jets with pT > 50 GeV one jet with pT > 550 GeV cos(θbW)>0.95 f=1000 GeV f S (fb) S/B S/√B 600 GeV 8.3 41.5 18.5√L 1000 GeV 6.54 32.7 14.6√L 1500 GeV 0.74 3.7 1.65√L σ (fb) / 20 GeV Bg: blue F->m_TH MtH

Conclusion and Outlook LHC opens the door for the new physics beyond SM Left-Right Twin Higgs model has rich collider phenomenology Study the heavy top partner at LHC Future works: Identify Twin Higgs mechanism Distinguish various new physics models, e.g. little Higgs Determine the spin of the heavy top partner