Is CP Symmetry Violation the Key to Explaining Matter-Antimatter Imbalance?

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    Cpt symmetry Symmetry
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Discussion Overview

The discussion centers on the concept of CP symmetry violation and its potential role in explaining the matter-antimatter imbalance in the universe. Participants explore theoretical implications, processes such as pair production and annihilation, and the relationship between time symmetry and these phenomena.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Technical explanation

Main Points Raised

  • One participant suggests that CP symmetry violation could explain the greater abundance of matter over antimatter, referencing observations of neutrino behavior.
  • Another participant questions the assumption that pair production in the presence of material is the time-reversed process of annihilation in a vacuum, seeking clarification on this point.
  • A different participant asserts that pair production cannot occur without the involvement of another photon or a massive particle, citing conservation of momentum as a limiting factor.
  • Some participants engage in a back-and-forth discussion about the nature of pair production and annihilation, comparing them to mathematical processes like integration and differentiation.

Areas of Agreement / Disagreement

Participants express differing views on the relationship between pair production and annihilation, with no consensus reached regarding their characterization as time-reversed processes. The discussion remains unresolved on several key points.

Contextual Notes

Participants have not fully addressed assumptions related to the conditions under which pair production and annihilation occur, particularly regarding the necessity of additional particles for momentum conservation.

Clever Penguin
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Consider a photon undergoing pair production and turn into a particle-antiparticle pair.

Now play this in reverse, you got a particle and an antiparticle colliding to create a single photon. But in annihilation, the result is two or more photons. Violation of T symmetry?

There also seems to be evidence of CP symmetry violation: '[There have been] 32 sightings of muon neutrinos morphing into the electron flavour, compared with just 4 muon antineutrinos becoming the anti-electron variety.'

Source: (https://www.newscientist.com/articl...at-why-antimatter-didnt-blow-up-the-universe/)

Although the above observations have only reached 2 sigma, many believe that this could be the reason why there is more matter than antimatter in the universe. In order for there to be more matter than antimatter in the universe, there has to be a process that violates CP symmetry, so why is this surprising?
 
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Clever Penguin said:
Violation of T symmetry?

No. Why do you think it is? In particular, why do you think pair production in the presence of material is the time-reversed process of annihilation in the vacuum?
 
Clever Penguin said:
Consider a photon undergoing pair production and turn into a particle-antiparticle pair.
This never happens due to conservation of momentum. There is always either another photon or a massive particle involved.
 
Vanadium 50 said:
No. Why do you think it is? In particular, why do you think pair production in the presence of material is the time-reversed process of annihilation in the vacuum?
Because they are the opposite process to each other. Like integration and differentiation. If I was to integrate 'backwards' it would be differentiation. :smile:
Dale said:
This never happens due to conservation of momentum. There is always either another photon or a massive particle involved.
I see. :smile:
 
Clever Penguin said:
Because they are the opposite process to each other.

Why do you think they are? Let me repeat, with emphasis:

"why do you think pair production in the presence of material is the time-reversed process of annihilation in the vacuum?"
 
Vanadium 50 said:
Why do you think they are? Let me repeat, with emphasis:

"why do you think pair production in the presence of material is the time-reversed process of annihilation in the vacuum?"

I see they are not... ?:)
 

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