2.5 Conservation rules

Question 1

Conservation of energy and conservation of charge

Answer 1

Apply to all changes in science, not just to all particle and antiparticle interactions and decays.
Conservation of energy includes the rest energy of the particles

Question 2

Conservation rules used only for particle and antiparticle interactions and decays

Answer 2

Essentially particle-counting rules, based on what reactions are observed and what reactions are not observed.
Conservation of lepton numbers
Conservation of strangeness

Question 3

Conservation of lepton numbers

Answer 3

In any change, the total lepton number for each lepton branch before the change is equal to the total lepton number for that branch after the change
_
μ+ –> e+ + vμ + ve

Question 4

Conservation of strangeness

Answer 4

In any strong interaction, strangeness is always conserved
Eg. K0 meson and a strange baryon called the neutral lambda particle (symbol Λ0) are produced when a π - meson collides with a proton:

π- + p –> K0 + Λ0

Question 5

An up quark and an up antiquark annihilate each other and the other quarks and antiquarks rearrange to form mesons. Is the baryon number conserved
___ _ _
uud + uud –> ud + ud

Answer 5

Baryon number is 0 (+1 -1) for the left hand side, and 0 for the right hand side.
Therefore, the baryon number is conserved

Question 6

Is the total baryon number conserved?

Answer 6

Yes. In ANY reaction