Simulation of weak decays

A) A file with electron momentum(px,py,pz) as a function of (x,y,z) in bins of size (deltax,deltay,deltaz)

B) A file with photons from external bremsstrahlung with momentum (0,0,pz) as a function of (x,y,z) in same bin sizes. As a first and maybe good enough approximation the photon momenta in px and py can be neglected since the photon spectrum is forward peaked. A refinement would be to include px and py but that would be a second calculations.

I am not sure of the bin size but a first approximation would be bins 1cm x 1cm x 1cm. Here I am guessing.

With such distributions of electron and photon momenta in the target one could subsequently start vertices anywhere in the target for pions, hyperons, etc and follow their paths or decay products through the magnets.