Problems Week 8
1. An excited atom has mass m. It emits a photon and goes into its
ground state with mass m0. Calculate the energy of the photon in the
initial rest frame of the atom (center-of-mass frame).
2. From the point-of-view of a certain observer the energy of a Σ-particle
is EΣ. It decays into a Λ-particle and a photon. The masses mΣ and
mΛ are known. Calculate the energy of the photon as a function of θ,
defined by the following picture (in the observers orthogonal space)
E ¡
¡
¡
¡
¡
¡!
d
d
d
d‚
Σ
Λ
γ
θ
3. In Compton scattering a photon scatters off an electron at rest. Relate
the energies Eγ and Eγ to θ:
E ¡
¡
¡
¡¡!
d
d
d
d‚
Eγ
Ee−
Eγ
θ
1