21: Elementary particles

Example number 21.1, Page number 399

In [3]:
#importing modules
import math
from __future__ import division

#Variable declaration
mpi=140;     #mass of pi-meson
mp=938.3;    #mass of proton
mk=498;   #mass of k
m=1116;  

#Calculation
Q=mpi+mp-mk-m;    #Q-value(MeV)

#Result
print "Q-value is",round(Q),"MeV"

Q-value is -536.0 MeV

Example number 21.2, Page number 399

In [5]:
#importing modules
import math
from __future__ import division

#Variable declaration
mpc2=938.3;    #energy of proton(MeV)
Epic2=139.6;   #energy of pi-meson(MeV)
mnc2=939.6;    #energy of neutron(MeV)
KE=0.6;    #kinetic energy of neutron(MeV)

#Calculation
Epi=mpc2+Epic2-mnc2-KE;    #energy conservation(MeV)
mpic2=math.sqrt((Epi**2)-((mnc2+KE)**2)+(mnc2**2));   #pi0 mass(MeV)

#Result
print "pi0 mass is",round(mpic2,1),"MeV"

pi0 mass is 133.5 MeV