What Form Did Matter and Antimatter Take During Annihilation After the Big Bang?

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Discussion Overview

The discussion revolves around the nature of matter and antimatter during the early universe, specifically focusing on the forms of matter and antimatter that underwent annihilation after the Big Bang. Participants explore the types of particles involved, such as baryons and mesons, and the significance of their annihilation processes.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant questions the form of matter and antimatter that was annihilated, specifically whether it was primarily baryons or mesons, and seeks to understand the ratio of their annihilation.
  • Another participant mentions that annihilation occurred between positrons and electrons, as well as quarks and antiquarks.
  • A further inquiry is made regarding the significance of baryon annihilation, specifically proton-antiproton and neutron-antineutron interactions.
  • One participant asserts that the initial asymmetry between quarks and antiquarks was minimal, providing a numerical estimate of the ratio.
  • Another participant references the Big Bang timeline, suggesting that protons, neutrons, and their antiparticles were indeed annihilated among each other.
  • A later reply acknowledges a previous mistake, clarifying that the initial asymmetry was established during baryogenesis and that annihilations occurred between baryons after the QCD phase transition.

Areas of Agreement / Disagreement

Participants express differing views on the significance of baryon versus meson annihilation, and while some agree on the occurrence of annihilation between baryons, the extent and details of these processes remain contested.

Contextual Notes

There are limitations regarding the assumptions made about the forms of matter and antimatter, as well as the specifics of the annihilation processes, which are not fully resolved in the discussion.

Deepak247
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Ive heard that soon after the big bang matter and antimatter was created in equal proportions and that majority of the matter-antimatter annihilated among each other, somehow only a small fraction of matter remained... my question is...

what was the form of the matter or antimatter which was annihilated?

was it mostly in baryons or mesons? i.e. mostly baryons annihilating among each other or mesons annihilating among each other?

what was the ratio?
 
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positrons with electrons; quarks with antiquarks
 
ok but how much was proton-antiproton and neutron-antineutron annihilation there?

i mean to say baryon annihilation...was it significant?
 
As I said, there was annihilation between quarks and antiquarks -- not baryons. The initial asymmetry between quarks, q, and antiquarks, \bar{q} was in fact not significant:
\frac{n_q - n_{\bar{q}}}{n_q} \simeq 10^{-8}
 
Yes, that is correct. Sorry, I was mistaken. The initial asymmetry was setup during baryogenesis, prior to baryon formation; the annihilations occurred between baryons after the QCD phase transition.
 

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