What is the potential explanation for the existence of matter in the universe?

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In summary, the conversation revolved around the open question of the existence of matter in the universe and the matter-antimatter imbalance. The hypothesis was proposed that electrons and neutrinos are actually antimatter particles, and that the missing antimatter in the universe may have been converted into these particles through some unknown mechanism. CP-symmetry violation and the decay of B-mesons were discussed as possible explanations for the matter-antimatter imbalance. The conversation also touched on the possibility of a hidden symmetry being broken early on in the universe. Overall, the conversation provided various theories and perspectives on the matter-antimatter problem in cosmology and particle physics.
  • #1
Science Advisor
One of the major open questions of particle physics is the existence of matter in the universe. At the time of the big bang, matter and antimatter were to supposed to have existed in equal quantities. What happened?

One thought I had (from out of nowhere) is that they do exist in equal amounts (numerically, not in mass), but we have been looking in the wrong place. My hypothesis is that electrons are antimatter. Moreover, the neutrinoes that are around are also antimatter. As a result there is a number balance. However, because of a yet to be discovered mechanism, the antiquarks or some predecessor antiparticles decayed into electrons and antineutrinoes, while the corresponding particles did not.

This just wild guessing - I have no evidence for it.
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  • #2
It is true that electron and neutrino both have antimatter particles, but why limit the existence of antimatter to these entities, why not also include anti-baryons and anti-mesons ? Both of these entities are known to be present in what we call "matter". If antimatter is in fact hidden within matter as a complex quantum superposition, then the problem is solved.
  • #3
You missed the point of what I was trying to say. Specifically, electrons are antimatter particles while positrons are matter particles. I was only concerned with stable particles. I know there is a whole zoo of mesons, etc. all of which have antipaarticles.
  • #4
This is what I call; TGT i.e total garbage theory, because we would be living in the anti-world and asking why is there so much anti-matter & not much matter.
  • #5
By convention, which is always somewhat arbitrary, protons and electrons are considered matter - at least in our part of the universe.

Anti-protons (which have a negative charge = electron charge) and positrons (the positively charged counterpart of the electron) are considered antimatter.

When protons and anti-protons annihilate, they can form hyperon resonances or meson showers depending on the energy of initial anti-proton.

When positrons and electrons annihilate, they form two [itex]\gamma[/itex]-rays with energies of at least 0.511 MeV each (the rest energy of an electron).
  • #6
One reason I am trying to see if electrons are better defined as antimatter is that the question of electrical neutrality of the universe can be answered as being a consequence of the fact that the matter-antimatter total must be in balance. By some unknown mechanism the antiprotons ended up as electrons.
  • #7
mathman said:
By some unknown mechanism the antiprotons ended up as electrons.
A little problem with that scenario is that electrons are leptons and antiprotons are baryons.

The rest mass of an electron is 0.511 MeV, while the antiproton rest mass is 938.2723 MeV, and antiprotons are composed of three quarks (or anti-quarks [itex]\bar{u}\bar{u}\bar{d}[/itex])

Take a look at these frames at hyperphysics - something to mull over:

Astrophysics concepts and cosmology.





Particle concepts


Cosmology and Matter/anti-matter problem

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  • #8
It is suspected by many physicists that the matter-antimatter discrepancy in the universe is due to the CP-symmetry violation of weak nuclear interactions. CP-symmetry violation occurs when a process which behaves a certain way under certain conditions does not behave the same way if the parity (up/down, right/left) is reversed and the charge is reversed (matter<-->antimatter). Clear evidence of this exists in the decay of what are called B-mesons. These particles consist of pairs of one quark and one antiquark. The particle can decay in many ways, but against the prediction of theory, it prefers to decay in some modes a bit more than others. It is this asymmetry that some believe caused a small amount of matter to be left over after the initial matter-antimatter annihilations of the early universe.
  • #9
It's a crazy, unreasonable, idea marcus, so it must be good! :bugeye:

As Astronuc has said, it's also very much agin the grain of the Standard Model of particle physics (leptons, hadrons, and all that). But who knows? Maybe some deep symmetry was broken very early on?

But wait! cefarix is onto something! If Sakharov was onto something, and CP violation is shown, experimentally (B factories, etc), to account for the observed matter-antimatter imbalance (as long as its embedded into a winning cosmological model, dontchya know), then we can all go the pub, right?
  • #10
I would like to clarify further the point that I was trying to make. There are (among others) two open cosmology questions in particle physics. First is the fact that the universe is made of matter. Second is the universe is electrically neutral.
In order to answer the first question, there needs to be some mechanism for antiquarks to disappear while leaving quarks behind. What I am trying to propose is that when this happens, electrons are part of the antiquark decay residue, thus taking care of the second question. That is why I am suggesting that electrons are antiparticles.
From what I have seen in SUSY theory, quark (and antiquark) decay into leptons is included, although to date no evidence of proton decay (demonstrating quark decay) has been seen.

1. What is matter-antimatter?

Matter-antimatter is a concept in particle physics where particles have corresponding antiparticles with the same mass but opposite charge. When matter and antimatter meet, they annihilate each other and release energy.

2. How is antimatter created?

Antimatter is created through high-energy collisions, such as those that occur in particle accelerators. In these collisions, energy is converted into matter and antimatter particles in equal amounts.

3. Why is there more matter than antimatter in the universe?

This is still a mystery to scientists. According to the Big Bang theory, equal amounts of matter and antimatter were created in the early universe. However, as the universe expanded and cooled, matter and antimatter particles collided and annihilated each other. Somehow, a tiny amount of matter was left over, which eventually formed into everything we see in the universe today.

4. What are the potential applications of antimatter?

Antimatter has been used in medical imaging and cancer treatment, as well as in experiments to study the fundamental nature of matter. It also has potential uses in propulsion for space travel, as it has a much higher energy density than traditional fuels.

5. Is antimatter dangerous?

In small amounts, antimatter is not dangerous. However, if a large amount of antimatter were to come into contact with a large amount of matter, it could result in a powerful explosion. Scientists take strict precautions when working with antimatter to prevent any such accidents from occurring.

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