2 5 50
  This function launches the total cross section 
evaluation for the reaction 2->2 using the 
integration by means of Simpson formula. The convolution 
of the matrix element squared with parton distribution 
functions is not available.
  It is possible to set the integration precision and
to display the distribution in the cosine of the scattering 
angle in the c.m.s., the total cross section and the 
integrated forward-backward asymmetry dependence on any 
parameter involved (e.g. energy).