Summary: Questions & Solutions On Particle Physics
Q1. A photon with an energy GeVE 09.2=
creates a proton-antiproton pair in which
the proton has a kinetic energy of MeV0.95 . What is the kinetic energy of the
S1. An antiproton has the same mass as a proton , so it seems reasonable to expect that
both particles will have similar kinetic energies .
The total energy of each particle is the sum of its rest energy and its kinetic energy .
Conservation of energy requires that the total energy before this pair production event
equal the total energy after .
( ) ( )ppRpRp KEKEE +++=
The energy of the proton is given as E .MeVGeV 3
From Table 46.2 ( S&B ) , we see that the rest energy of both the proton and the
MeVcmEE ppRRp 3.9382
If the kinetic energy of the proton is observed to be MeV0.95 , the kinetic energy of
the antiproton is
( ) MeVMeVMeVKEEEK pRppRp 0.9551009.2 3