Message 2489 from Andrew Gray, 02 February 2007 19:31:
In response to message 2425: Accelerated Reference Frames from Andrew Gray , 06 January 2007:
The paradoxical situation here is that the (finite) total cross section stays the same whatever the scattering angle i.e. also for a zero scattering angle (infinite height of the cone), whereas the differential cross section (as given by the surface of the cone) increases linearly with the height of the cone. Again, this discrepancy can only be resolved by multiplying the factor sin(Θ/2) to the total cross section.
OK, now I understand what you are saying. So your weighted cross section has to do with a "direct head-on collision" probability. OK, I see. I will think about how this applies to the Bremsstrahlung radiation.