CERN Program Library Long Writeup W5013 - CERNLIB ...

Therefore, the differential cross-section can be written as
dσ
dv
= f(v)g(v) (2)
with
f(v) =
g(v) =
[
v ln
1
Φ(0)
( )] −1 vmax
v c
(1 − v + 3 4 v2 )
Φ(δ)
We can sample the photon energy in the following way (r 1 , r 2 uniformly distributed random numbers in
]0, 1[):
1. sample v:
( ) r1 vmax
v = v c
v c
2. compute the rejection function g(v) and:
(a) if r 2 >g(v) go back to step 1
(b) if r 2 ≤ g(v), accept v and k = vE.
After the successful sampling of k, GBREMM generates the polar angles of the radiated photon with respect to
an axis defined along the parent muon’s momentum calling GBTETH. For more information on the sampling
procedure see [PHYS341].
PHYS441 – 2 312