Exploring Anti-Matter: Why Aren't Atoms Composed of Positrons & Antiprotons?

In summary, according to current theories, atoms are not composed of positrons and antiprotons because of something called CP-violation. This is a subtlety that is required in addition to CP violation in order to produce the baryon asymmetry.
  • #1
zalnas
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I've recently learned more about antimatter, namely what types there are, and one question has stuck in my mind: why are atoms not composed of Positrons and Antiprotons? Since scientists at the LHC recently were able to contain antihydrogen, it seems that these atoms, while isolated from matter, are stable.
 
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  • #3


zalnas said:
I've recently learned more about antimatter, namely what types there are, and one question has stuck in my mind: why are atoms not composed of Positrons and Antiprotons? Since scientists at the LHC recently were able to contain antihydrogen, it seems that these atoms, while isolated from matter, are stable.

Anti-matter in isolation is stable, as the LHC experiment demonstrated. However, when coming into contact with matter, there is mutual annihilation. As far as it is known, the universe is composed of baryonic matter (ordinary matter), dark matter, and dark energy. Anti-matter couldn't survive.
 
  • #4


Kevin_Axion said:
Because of something called CP-Violation: http://en.wikipedia.org/wiki/CP_violation.

Perfect, thank you! That is exactly the explanation I was looking for.

Anti-matter in isolation is stable, as the LHC experiment demonstrated. However, when coming into contact with matter, there is mutual annihilation. As far as it is known, the universe is composed of baryonic matter (ordinary matter), dark matter, and dark energy. Anti-matter couldn't survive.

I was specifically wondering why antimatter didn't take precedence in the formation of the universe; I understand that it would not survive in the current state of the universe.
 
  • #5


Kevin_Axion said:
Because of something called CP-Violation: http://en.wikipedia.org/wiki/CP_violation.

In all known models (based on QFT) CP violation is necessary to produce baryon-antibaryon asymmetry. But it is far from sufficient, and definitely not automatic. The presence of CP violation does not automatically generate this asymmetry. Something far more subtle is needed in addition to CP violation. What that might be is model dependent, and it is a subject matter of much heated discussion. Needless to say, we do not know how exactly the baryon asymmetry arose in the early universe. There are plausible models, but that's all.
 
  • #6


If we were comprised of 'anti matter', and so considered it 'normal', would we know otherwise until the CP-violation surfaced ??
 

1. What is anti-matter and how is it different from regular matter?

Anti-matter is a type of matter that is composed of particles with the opposite charge of regular matter. For example, while regular matter is composed of protons, neutrons, and electrons, anti-matter is composed of antiprotons, antineutrons, and positrons. This means that when matter and anti-matter come into contact, they annihilate each other, releasing a large amount of energy.

2. Why aren't atoms composed of positrons and antiprotons instead of protons and electrons?

The reason for this is still a mystery in the scientific community. One theory is that during the early stages of the universe, there was an imbalance between matter and anti-matter, resulting in the majority of matter surviving and forming the universe as we know it. Another theory suggests that the laws of nature favor the formation of regular matter over anti-matter.

3. How is anti-matter created and studied in the lab?

Anti-matter is created in the lab through various processes, such as particle accelerators and high-energy collisions. Once created, it can be studied using specialized equipment that can detect and measure its properties, such as charge and mass.

4. Is anti-matter dangerous to humans?

Anti-matter is not inherently dangerous to humans. While the annihilation of matter and anti-matter releases a large amount of energy, this only occurs when they come into contact with each other. Scientists take precautions to prevent this from happening in the lab, and anti-matter does not exist in large enough quantities in nature to pose a threat.

5. Could anti-matter be used as a source of energy?

While the annihilation of matter and anti-matter releases a large amount of energy, it is currently not a viable source of energy for practical use. The process of creating and storing anti-matter requires a significant amount of energy and is not yet efficient enough to be a feasible source of energy. However, research in this area is ongoing, and it is possible that it could be utilized in the future as a source of energy.

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