W and H+ polarizations in top decays

1. Generate %$e^+e- \to t \bar t$% at threshold and force the tops to decay leptonically (to %$e$% or %$\mu$%).
   1. Compare the charged and neutral lepton %$p_T$% (or energy) distributions with those shown in the MC lectures.
   2. Explain why the neutrinos tend to have higher %$p_T$% than the charged leptons.
   3. How would things change if the decay went via %$t\to b H^{+$% with %$m_{H}+}=m_W$%? Check by using

the 2HDM (Use the on-line calculator to get a consistent set of parameters for the 2HDM).

1. As the previous exercise, but in %$pp \to t\bar t$% at the LHC.

-- Main.FabioMaltoni - 06 Dec 2008