Environmental Engineering Reference
In-Depth Information
7.9 An antiproton of kinetic energy 0.667 GeV strikes a proton which is at rest
in the laboratory. They annihilate to produce two photons which emerge
from the reaction travelling forward or backward on the line along which the
antiproton entered.
(a) What energies do the photons have?
(b) In which direction is each photon heading?
(c) As measured in a frame attached to the incoming antiproton, what is the
energy of each photon?
[The mass of an antiproton is equal to that of a proton, i.e. 938 MeV/
c
2
.]
7.10 Two particles, each of mass
m
, are moving perpendicular to each other with
speeds
u
1
and
u
2
. The particles collide and coalesce to form a single particle
of mass
M
. Show that
M
2
2
m
2
(
1
=
+
γ(u
1
)γ (u
2
))
