1. Xinyu Miao Department of Physics Univ. of Arizona 03/30/07
Heavy top LHC
Xinyu Miao
Department of Physics
Univ. of Arizona
03/30/07

2. Outline Large Hadron Collider
Hierarchy Problem and the little Hierarchy Problem
Left-Right Twin Higgs model
Study of the Heavy Top at the LHC
Conclusion

3. Large Hadron Collider
LEP II
~200GeV
~1.96TeV
Tevtron
~14TeV
LHC

4. A TeV is a unit of energy used in particle physics.
1 TeV is about the energy of motion of a flying mosquito.
What makes the LHC so extraordinary is that it squeezes energy into a space about a million million times smaller than a mosquito.

5. Large Hadron Collider

6. Standard Model

7. The Hierarchy Problem Plank Scale SM Higgs mass ~100GeV
EW Scale~100GeV

8. The Little Hierarchy

9. Possible Solution
What if ?

10. Twin Higgs model Heavy Top SM Top SM Gauge Boson Heavy Gauge Boson
L-R Symmetry
tHeavy
tSM
SM Gauge Boson
Heavy Gauge Boson
L-R Symmetry
 log 

11. Heavy Particles WH
~3TeV tH
~1TeV 
~300GeV

12. Heavy top tH production

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

14. 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
MtH

15. 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