Questions tagged [baryogenesis]
96 questions
57
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Why is matter-antimatter asymmetry surprising, if asymmetry can be generated by a random walk in which particles go into black holes?
My understanding is the early universe was a very "hot" (ie energy dense) environment. It was even hot enough for black holes to form from photons.
My second point of understanding is that black holes can lose mass due to hawking radiation, which…
Livid
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53
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3 answers
How would we tell antimatter galaxies apart?
Given that antimatter galaxies are theoretically possible,
how would they be distinguishable from regular matter galaxies?
That is, antimatter is equal in atomic weight and all properties, except for the opposite reverse charge of the particles,…
Soren
- 843
31
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2 answers
Experimental observation of matter/antimatter in the universe
Ordinary matter and antimatter have the same physical properties when it comes to, for example, spectroscopy. Hydrogen and antihydrogen atoms produce the same spectroscopy when excited, and adsorb the same frequencies. The charge does not make a…
Stefano Borini
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Does the number density of photons $n_\gamma\approx 10^8 \:\mathrm m^{-3}$ refer to CMB photons only?
When we talk about the present-day number density of photons ($n_\gamma\approx 10^8 \:\mathrm m^{-3}$) in the universe do we mean the number density of CMB photons? I mean there are other sources of photons, for example, stellar or galactic…
SRS
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17
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Matter-Antimatter Asymmetry in Experiments?
As I hope is obvious to everyone reading this, the universe contains more matter than antimatter, presumably because of some slight asymmetry in the amounts of the two generated during the Big Bang. This raises the question of whether there are any…
Chad Orzel
- 8,646
14
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1 answer
Baryogenesis only at the Planck scale, or none at all?
I can think of three general ways of explaining why the universe contains more matter than antimatter:
(1) Near the Planck time, the universe had zero baryon asymmetry, but at some later time, determined by some GUT energy scale, the Sakharov…
user4552
14
votes
2 answers
If all the Structure in our visible Universe originated from Quantum Fluctuations, why isn't there as much Anti-Matter as Matter?
According to inflation, all the structure that we see like galaxies, etc. originated from quantum fluctuations which were expanded during inflation. But since quantum fluctuations always create particle-anti particle pairs, doesn't that mean that…
alex
- 1,195
14
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4 answers
Temperature of electroweak phase transition
How does one estimate the temperature at which electroweak phase transition (EWPT) occurred? Somewhere I have read it is around 100GeV but the reason was not explained.
SRS
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12
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Understanding Sakharov's third condition for baryogenesis (departure from thermal equilibrium)
I'm struggling to understand Sakharov's third condition for baryogenesis, i.e., a departure from thermal equilibrium. I don't understand what thermal equilibrium means in this context or proofs that it is neccessary for baryogenesis.
Trodden and…
innisfree
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12
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1 answer
Difference between instantons and sphalerons
What is the difference between instantons and sphalerons? If they are different, how do they violate baryon and lepton number in the standard electroweak theory?
SRS
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Theta Vacuum of Yang-Mills theory and Baryon number violation
Background 1. In classical SU(N) Yang-Mills theories, there are a countably infinite number of homotopically inequivalent gauge field configurations of zero energy labelled by a winding number $n\in \mathbb{Z}$. In the corresponding quantum theory,…
SRS
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4 answers
Baryon asymmetry
Baryon asymmetry refers to the observation that apparently there is matter in the Universe but not much antimatter. We don't see galaxies made of antimatter or observe gamma rays that would be produced if large chunks of antimatter would annihilate…
Marton Trencseni
- 3,105
8
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1 answer
Has non-conservation of baryon number been observed?
CP violation (as I understand it) allows for non-conservation of baryon number, and thus can contribute (at least a little) to the baryon asymmetry in the universe today (far more matter than antimatter).
But have we ever seen baryon number change…
Kevin Kostlan
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8
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Does Leptogenesis require lepton number violating vertices?
One of the Sakharov condition for Baryogenesis requires Baryon number violating interactions in the theory. However, it is also possible to generate a baryon asymmetry via a lepton asymmetry or Leptogenesis. Therefore, for Baryogenesis through…
SRS
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Why is baryon or lepton violation in standard model is a non-perturbative effect?
The baryon number B or lepton number L violation in the standard model arise from triangle anomaly. Right? Triangle diagrams are perturbative diagrams. Then why the B or L violation in Standard model is said to be a non-perturbative effect? I'm…
SRS
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