Page 96 - Special Issue Modern Trends in Scientific Research and Development, Case of Asia

International Journal of Trend in Scientific Research and Development (IJTSRD) @ www.ijtsrd.com eISSN: 2456-6470

muon and tau neutrino, respectively. It follows from the Since the net baryon numbers of the reactants and products
experiment that these are different neutrinos. are equal, this reaction is allowed on the basis of the baryon
number conservation law.
We agreed to consider that
For reaction (b), the net baryon number of the reactants is
+ for 1 leptons 1+ ( ) 01 =- and the net baryon number of the proposed
L =L =L = 
e m t - for 1 antilepton s products is 1+ 1+ ( ) 11 =-
 . Since the net baryon numbers of
the reactants and proposed products are not equal, this

reaction cannot occur.
For all other elementary particles, lepton charges are taken

to be zero.
Significance
Baryon number is conserved in the first reaction, but not in
The law of conservation of the lepton charge requires that the second. Baryon number conservation constrains what
during neutron decay reactions can and cannot occur in nature.

~
-
n ® p + e + n Example2: Lepton number conservation
e
Based on the law of conservation of lepton number, which of
together with the electron, an electron antineutrino was the following decays can occur?
-
born, since the total lepton charge of these two particles is a) n ® p + e + n
e
zero. - -
) b p ® m + n + n
m
m

The law of conservation of lepton charge explains the
Strategy
impossibility of the following processes:
Determine the total lepton number for the reactants and

products, and require that this value does not change in the
reaction.

Solution
although they are permitted by other conservation laws. The
For decay (a), the electron-lepton number of the neutron is
processes
0, and the net electron-lepton number of the decay products
~ ~ is 0 + 1+ (- ) 1 = 0 .
+
n + p ® e + , n n + p ® m + + , n
e m
Since the net electron-lepton numbers before and after the
satisfying the lepton charge conservation law were observed decay are the same, the decay is possible on the basis of the
experimentally. After it was experimentally established that law of conservation of electron-lepton number. Also, since
n and n are different particles, different lepton charges there are no muons or tau-leptons involved in this decay, the
e m
muon-lepton and tau-lepton numbers are conserved.
L and L were introduced. Similarly, the situation was
e m
-
with the introduction of the tau lepton charge L [6-7]. For decay (b), the muon-lepton number of the p is 0, and
t
the net muon-lepton number of the proposed decay products

III. RESULTS is 1+ 1+ ( ) 11 =- .
We consider some problems below.
Thus, on the basis of the law of conservation of muon-lepton
Example1: Baryon number conservation. number, this decay cannot occur.

Based on the law of conservation of baryon number, which Significance
of the following reactions can occur? Lepton number is conserved in the first reaction, but not in
a) p - +p ® p 0 +n +p - +p the second. Lepton number conservation constrains what
+
b) p + p ® p + p + p reactions can and cannot occur in nature.

IV. CONCLUSION
Strategy Like the law of conservation of momentum, based on the
Determine the total baryon number for the reactants and isotropic nature of our ordinary space, a particular
products, and require that this value does not change in the momentum-spin is conserved in all interactions. These
reaction. conservation laws are fulfilled in all processes occurring
with particles, and have the property of controlling all
Solution processes in the world of particles. When studying the
For reaction (a), the net baryon number of the two reactants physics of elementary particles, the analysis of the
is 0 + 1 = 1 and the net baryon number of the four products fulfillment of these conservation laws by the example of
is 0 + 1+ 0 + 0 = 1. specific processes will undoubtedly help to increase the
efficiency development of this field. To this end, the next task
in studying the fundamentals of elementary particle physics

ID: IJTSRD37941 | Special Issue on Modern Trends in Scientific Research and Development, Case of Asia Page 91