 classes are not intended for general use,
and so are not described here. 

<p/>
In addition to the parameters described on this page, note that the 
choice of <a href="PDFSelection.html" target="page">parton densities</a> is made 
in the <code>Pythia</code> class. Then pointers to the pdf's are handed 
on to <code>BeamParticle</code> at initialization, for all subsequent 
usage.

<h3>Primordial <i>kT</i></h3>

The primordial <i>kT</i> of initiators of hard-scattering subsystems 
are selected according to G