# Chapter 14:Elementary Particles¶

## Example 14.2, Page 451¶

In :
#initiation of variable
mvo=1116.0;mp=938.0;mpi=140.0;    #mass of various particles

#calculation
Q=(mvo-mp-mpi);            #Q value of energy
Pp=100.0;Ppi=100;            #momentum of various particles
Kp=5.0;Kpi=38-Kp;            #kinetic energy of particles

#result
print "The kinetic energy of the particles Kp and Kpi are", Kp," MeV and",Kpi," MeV respectively"

 The kinetic energy of the particles Kp and Kpi are 5.0  MeV and 33.0  MeV respectively


## Example 14.3, Page 453¶

In :
#initiation of variable
Q=105.2                    # The Q value for the given decay
Muc2=105.80344         #mass energy

#calculation
Ke= Q**2/(2*Muc2);       #Ke=Ee-mec2;

#result
print "The maximum kinetic energy in MeV is",round(Ke,3);

The maximum kinetic energy in MeV is 52.3


## Example 14.4, Page 455¶

In :
#initiation of variable
from __future__ import division
from sympy.solvers import solve
from sympy import Symbol
from sympy import *
from math import sqrt
mkc2=494.0; mpic2=135.0;mec2=0.5;# mass of various particles

#calculation
Q1=mkc2-mpic2-mec2;       #Q of reaction
# the neutrino has negligible energy
x = symbols('x')
k=solve((x**2+135.0**2)**(0.5)+x-494,x);# assigning the Q to sum of energies and simplifying

print "The value of maximum kinetic enrgy for pi-meson  and positron are",266,"MeV &",k," MeV";

 The value of maximum kinetic enrgy for pi-meson  and positron are 266 MeV & [228.553643724696]  MeV


## Example 14.5, Page 457¶

In :
#initiation of variable
mpi_=140;mp=938;mKo=498;mLo=1116; #mass of various particles

#calculation
Q1= mpi_+mp-mKo-mLo;          #Q value of reaction 1
mK_=494.0;mpio=135.0;
Q2=mK_+mp-mLo-mpio;         #Q value of reaction 2

#result
print"The Q values of reactions 1 and 2 are", Q1," MeV and",Q2,"MeV";

The Q values of reactions 1 and 2 are -536  MeV and 181.0 MeV


## Example 14.6, Page 459¶

In :
#initiation of variable
mpic2=135.0;        #mass energy of pi particle

#calculation
Q=-mpic2;
mp=938.0;mpi=135.0;
Kth=(-Q)*((4*mp)+mpi)/(2*(mp));  #threshold energy

#result
print"The threshold kinetic energy in MeV is",round(Kth,3);

The threshold kinetic energy in MeV is 279.715


## Example 14.7, Page 460¶

In :
#initiation of variable
mpc2=938.0;   #rest energy of proton

#result
Q=mpc2+mpc2-(4*mpc2);        #Q value of reaction
Kth=(-Q)*(6*mpc2/(2*mpc2));       # thershold kinetic energy

#result
print "The threshold kinetic energy in MeV is",round(Kth,3);

The threshold kinetic energy in MeV is 5628.0