Question about relative abundance of particles before annihilation

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SUMMARY

The discussion focuses on the relative abundance of particles and antiparticles before their annihilation, specifically addressing protons/neutrons versus anti-protons/anti-neutrons, and electrons versus positrons. The user, Buzz, seeks clarification on the assumptions regarding the rest mass of particles and their relativistic speeds at high temperatures. Key points include the assertion that the relative abundance of particles (1) and (2) would be similar before annihilation, and that the number density of electrons and positrons would decline inversely with the scale factor a, influenced by temperature changes. Buzz acknowledges previous misunderstandings and expresses a need for further clarification on these concepts.

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  • Understanding of particle physics, specifically particle-antiparticle pairs.
  • Familiarity with concepts of relativistic speeds and their implications on particle behavior.
  • Knowledge of thermal equilibrium and its effects on particle abundance.
  • Basic grasp of cosmological expansion and scale factors in the universe.
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  • Explore the relationship between temperature and particle abundance in high-energy physics.
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Physicists, cosmologists, and students of particle physics seeking to deepen their understanding of particle-antiparticle dynamics and the effects of temperature and expansion on their relative abundances.

Buzz Bloom
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I am looking to correct my understanding about the relative abundance of particles and antiparticles created before the two periods of annihilation:
(1) protons/neutrons and anti-protons/anti-neutrons, and
(2) electrons and positrons.​

In a previous thread
I presented my understanding about this, but I have since decided that I made some mistakes. I had previously assumed that the relative rest mass of particles was relevant to their relative abundance, but I overlooked that at temperatures high enough for all particles to be created with relativistic speeds the relative rest masses were insignificant.

So, what I would like is someone to either to confirm or correct the following ideas:
(a) Well before the period of (1) annihilation, the relative abundance of (1) particles would be about the same as that of the (2) particles.
(b) Just before (1) annihilation, the (1) particles would not be relativistic when created, but the (2) particles would be.​
Question 1: What would the relative abundance of (1) and (2) particles be just before (1) annihilation?
(c) After (1) annihilation, but before (2) annihilation, the number density of (2) particles would decline as the scale factor a increased with expansion. This decline would be inversely proportional to a3. However, the decline should be faster than this because the temperature is also declining, and that should also have an effect on the equilibrium between the creation of (2) particles and their mutual annihilation.​
Question 2. How does the equilibrium abundance of a protons and electrons depend on temperature.

I will have some more questions later, but getting answers to the above is my first priority.
 
Greg Bernhardt said:
is it possible to reword the post?
Hi @Greg Bernhardt:

Thanks for the automated encouragement. I am not sure that it is easy for anyone to answer any of my questions, or to find a reference that would help. I guess I was too optimistic in putting this post together. I think the best thing I can try is to start a new thread with just one of the questions.

Regards,
Buzz
 
Thread closed as the OP has started a new one.
 

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