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