Touschek effect
The Touschek effect describes the scattering and loss of charged particles in a storage ring. It was discovered by Bruno Touschek.
It is determined by the average of the scattering rate around the ring
In fact, since the momentum acceptance for scattering with energy gain may be different from that for scattering with energy loss, the lifetime must be computed by taking into account the positive and negative momentum acceptances, i.e.