Scarcity of antimatter atoms

  • #1

Main Question or Discussion Point

Are there any answers to this question? If equal amounts of matter and antimatter were in existence at the big bang surely each annihilation would remove equal amounts of matter and antimatter?
 

Answers and Replies

  • #2
Nabeshin
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This is one of the big open questions in theoretical physics.

We know of asymmetries between matter and antimatter, but none of them are large enough to produce the observed baryon asymmetry.
 
  • #3
I've just read up on mesons. Would they occur naturally and do they interact with matter?
 
  • #4
phyzguy
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Are there any answers to this question? If equal amounts of matter and antimatter were in existence at the big bang surely each annihilation would remove equal amounts of matter and antimatter?
Bear in mind that the asymmetry between matter and antimatter appears to be very small. Today in the universe there are about 10^9 photons for every baryon. So we think (for some reason we don't fully understand, as Nabeshin said) that there was just slightly more matter produced than antimatter, by only 1 part in 10^9. So after it all annihilated, we were left with matter and photons.
 
  • #5
Bear in mind that the asymmetry between matter and antimatter appears to be very small. Today in the universe there are about 10^9 photons for every baryon. So we think (for some reason we don't fully understand, as Nabeshin said) that there was just slightly more matter produced than antimatter, by only 1 part in 10^9. So after it all annihilated, we were left with matter and photons.
Thanks for the answer that makes sense of the situation.
 
  • #6
555
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Are there any answers to this question? If equal amounts of matter and antimatter were in existence at the big bang surely each annihilation would remove equal amounts of matter and antimatter?
At least some of the asymmety is due to CP violation. Read up on the BaBar experiment. B and anti-B interactions were observed to lead to stable matter in some cases.
 
  • #7
At least some of the asymmety is due to CP violation. Read up on the BaBar experiment. B and anti-B interactions were observed to lead to stable matter in some cases.
Maybe antimatter is just not meant to exist on its own and is just another component of matter. We think of it as antimatter whereas it is really only a subset of matter.
 
  • #8
Drakkith
Staff Emeritus
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Maybe antimatter is just not meant to exist on its own and is just another component of matter. We think of it as antimatter whereas it is really only a subset of matter.
Both matter and antimatter are really just plain "matter". Antimatter does not have exotic properties or anything like that. If the universe were dominated by antimatter instead, we would know that as "matter" and the other as "antimatter".
 
  • #9
K^2
Science Advisor
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I've just read up on mesons. Would they occur naturally and do they interact with matter?
Yes and yes. Sufficiently high energy radiation can produce mesons. These energy levels are typical of stars and radiation they emit, but can also be due decay of many naturally occurring radioactive isotopes.

Mesons are matter. But I'm guessing you might mean more conventional matter, like atomic nuclei and electrons. Yes, mesons will interact with these.

None of the mesons are stable, however. They all have very short life times.
 

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