Why Does Antimatter Exist if It's Not Found in Nature?

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Discussion Overview

The discussion centers around the existence of antimatter, exploring the reasons for the observed asymmetry between matter and antimatter, particularly in the context of theoretical physics and cosmology. Participants delve into concepts such as chirality, CP violation, and the production of antimatter in high-energy collisions.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants express confusion about the existence of antimatter and seek explanations for the asymmetry between matter and antimatter.
  • One participant notes that Dirac's work led to the understanding of antiparticles and mentions that antimatter should have existed in equal quantities after the big bang, with a slight excess of matter surviving annihilation.
  • Another participant questions the terminology used regarding CPT violation and suggests it should be referred to as CP violation.
  • Some argue that antimatter exists only in laboratories and is synthesized artificially, while others assert that positrons and antiprotons exist in nature but are rare and quickly annihilate upon contact with matter.
  • Chirality is discussed as a factor in the existence of matter versus antimatter, with claims that matter follows a right-handed rule of chirality and antimatter follows a left-handed rule.
  • Participants debate the accuracy of descriptions regarding anti-Helium and the necessity of antineutrons, with some asserting that neutrons and antineutrons are fundamentally different.
  • There is contention over the claim that matter and antimatter are absolutely identical except for charge, with some pointing out that CP violation indicates they are not identical in all respects.
  • One participant questions whether antimatter existed immediately after the big bang, seeking clarification on the definition of "found in nature."

Areas of Agreement / Disagreement

Participants express multiple competing views regarding the existence and properties of antimatter, particularly concerning chirality, the nature of particles, and the implications of CP violation. The discussion remains unresolved with no consensus reached.

Contextual Notes

Some claims rely on specific definitions of chirality and the role of weak interactions, which may not be universally accepted. The discussion also highlights the complexity of particle interactions and the nuances in the understanding of antimatter.

cjackson
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I don't understand why antimatter exists in the first place. Could you explain why and how an asymmetry developed between matter and antimatter?
 
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Dirac was the first to realize the relativistic version of the Schrödinger wave equation permitted anti particle counterparts to ordinary particles. We now know anti particles are routinely produced by high energy collisions between particles, and that anti matter should have existed in equal quantities shortly after the big bang. For reasons unknown, a slight excess [roughly one in a million] of matter particles survived the mutual annihilation frenzy that followed. The reason for this asymmetry is one of the great mysteries in science. Some as of yet unknown form of CPT violation is the prime suspect.
 
Chronos said:
Some as of yet unknown form of CPT violation is the prime suspect.
You mean CP violation, right?
 
I don't understand why antimatter exists in the first place. Could you explain why and how an asymmetry developed between matter and antimatter?

Anti-matter exists only in the laboratory - artificially - through synthesis.

Matter and Antimatter are absolutely identical and indistinguishable in every aspect
other than charge.

Helium is composed of 2 (+) protons, 2 neutrons and 2 (-) electrons

Anti-Helium is composed of 2 (-) Anti-protons, 2 neutrons and 2 (+) positrons (anti-electrons)


The reason matter exists in nature and Anti-matter has to be synthesized
is due to Chirality (helical oriention) All matter follows the right-handed rule of chirality,
Anti-matter follows the left-handed rule of chirality, and is not found in nature.

Absolute symmetry is allowed in mathematics - in the Dirac equation for example,
however this is not true of all interactions in nature.

Equations are only abstract tools for calculating interactions in nature,
Equations do not describe the causes of interactions, nor can they explain a natural phenomenon.

Causes are the domain of practical experimental physics and not theoretical mathematics.
 
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euclideanspace said:
Anti-Helium is composed of 2 (-) Anti-protons, 2 neutrons and 2 (+) positrons (anti-electrons)

For antiHe you need antineutrons. They are not the same as neutrons. Two neutrons meeting together will not annihilate, while a neutron with antineutron can annihilate .
Also it would be much easier and more illustrative to speak of electron and positron, rather than going to a composite system.
 
For antiHe you need antineutrons. They are not the same as neutrons

Correct, this was only a simplified explanation of the principle

Anti-Neutrons are composed of Antiquarks and Neutrons are composed of Quarks
this is the only difference - and is also due to Chirality.
 
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euclideanspace said:
Anti-matter exists only in the laboratory - artificially - through synthesis.
Positrons and antiprotons exist in nature, they are just rare and if they hit matter (like earth) they annihilate quickly.

Matter and Antimatter are absolutely identical and indistinguishable in every aspect
other than charge.
And all other quantum numbers. And they are not absolutely identical, there is CP violation.

The reason matter exists in nature and Anti-matter has to be synthesized
is due to Chirality (helical oriention) All matter follows the right-handed rule of chirality,
Anti-matter follows the left-handed rule of chirality, and is not found in nature.
This is just wrong. Only the weak interaction cares about chirality at all, and this interacts only with left-handed fermions ("matter"), not with right-handed.

Correct, this was only a simplified explanation of the principle
How is it "simplified" to list wrong particles?
 
euclideanspace said:
Anti-matter exists only in the laboratory - artificially - through synthesis.
...

Anti-matter follows the left-handed rule of chirality, and is not found in nature.

Are you saying that there was no antimatter just after the big bang singularity or do you somehow exclude that from "found in nature" ?
 

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