Questions tagged [baryogenesis]
The baryogenesis tag has no usage guidance.
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Why do we assume that there had to be a baryon-antibaryon-symmetry in the first place?
Maybe this is obvious to some, however I have not found a satisfying answer yet.
Detailed answers appreciated!
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Where is all the Antimatter?
This is obviously a duplicate of If matter and antimatter... However, it's now four to five years after a swarm of videos were made on this subject. At the time, there was a consensus that the LHC ...
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Chemical equilibrium for a $2-2$ scattering and Boltzmann equation in cosmology and astroparticle physics
Definition of chemical equilibrium According to the definition of chemical equilibrium in Wikipedia, it is a situation where the rate of the forward reaction is same as the rate of backward reaction ...
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Can the CKM matrix supply the CP asymmetry as required by baryogenesis, in principle?
In the process of Baryogenesis through Leptogenesis from the decay of heavy Majorana neutrinos, the necessary CP violation is perhaps provided only by the CP phases in the PMNS matrix. But the Weak ...
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Matter Anti-matter Imbalance
If both matter and antimatter could still 'pouring out', why do we assume that there is an overall Matter Anti-matter Imbalance? Could not antimatter possibly come out during a different time as ...
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Is baryon asymmetry universal? [duplicate]
Baryon asymmetry takes it place on the Earth: it is almost impossible to find antimatter on the Earth, but matter occurs here and there. We ourselves are composed of matter and interact with matter to ...
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1answer
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Is the inflaton field baryon symmetric?
The theory states that after inflation ends, the energy stored in the inflaton field decays to produce particles.
Does the inflaton field have baryon number associated with it?
Is the field baryon ...
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Could matter in the universe come from some process other than the decay of inflaton field?
Could matter in the universe come from some process other than the decay of inflaton field?
Do we have any theoretical reasons that support the idea that matter was created from the decay of ...
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Entropy production during leptogenesis
Do the out of equilibrium decays of right-handed neutrinos in standard leptogenesis scenarios lead to a net entropy production? Does this entropy production lead to observable effects (like reheating)?...
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Baryon asymmetry still going on
I read these questions and answers and it made me curious.
Baryon asymmetry
Why do we believe baryon asymmetry?
Why does matter-antimatter asymmetry only refer to baryon asymmetry?
How does ...
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2answers
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Why abundance of matter requires fundamental asymmetry - cannot be statistical symmetry breaking?
There are rather no doubts that there is more matter than antimatter in our Universe, it is usually assumed that it was created during short baryogenesis (violating baryon number conservation) period ...
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Why is there not enough CP violation to account for baryogenesis in the SM?
One of Sakharov conditions states that both C and CP symmetries must be violated by a theory which includes any baryogenesis mechanism. The Standard Model happens to be such a theory, and happens to ...
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Antimatter/Matter energy release
I am not a physicist, nor do I have a university degree, but I have a question that has been on my mind for some time.
If Antimatter and Matter were created equally during the 'Big Bang' would the ...
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Can an anti-hydrogen atom decay into a hydrogen atom?
I was thinking about Baryon asymmetry just to mess around with ideas and thought about this. Could it be that all the anti-matter decayed into matter?
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Baryon number violation in the Standard model at the perturbative and non-perturbative level
This is a continuation of my question here.
Page 635 of this book by Matthew Schwartz effectively says that the $\partial_\mu J^\mu_B\neq 0$ where $J^\mu_B$ is the baryon current i.e., the baryon ...
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Quantifying the baryon asymmetry requires normalizing the baryon number density w.r.t comoving entropy density or photon density-Why?
This question has been edited a little to clarify the confusion I have.
The matter-antimatter asymmetry of the Universe quantified by the baryon asymmetry as
$$Y_B=\frac{n_B-n_{\bar{B}}}{s}=\frac{n_B}...
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Could baryon asymmetry be negative?
In the paper http://hamilton.uchicago.edu/~harvey/pdf_files/harvey_turner_1990.pdf,
it can be seen from expressions (9a, 9b,9c) that barygon asymmetry is proportional to negative lepton asymmetry. But ...
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3answers
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Is the gravitational pull of the early ($10^{10}$ more massive) universe still observable?
During one of the early epochs of the universe it used to be 10^10 times more massive than it is now, just before the matter / antimatter annihilation. So what cosmic gravity is being asserted on the ...
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If all the Structure in our visible Universe originated from Quantum Fluctuations, why isn't there as much Anti-Matter as Matter?
According to inflation, all the structure that we see like galaxies, etc. originated from quantum fluctuations which were expanded during inflation. But since quantum fluctuations always create ...
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Why is the quantum number $\frac{1}{3}B-L_\alpha$ said to conserved in the Standard model rather than $B-L$?
In the standard model, the baryon number $B$ and the lepton number$L$ are conserved perturbatively. However, the B+L quantum number is anomalous and is violated via non-perturbative effects while ...
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3answers
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Number excess of baryons per antibaryon in a comoving volume: Interpreting $Y_{\Delta B}$ in the present epoch
The baryon asymmetry of the Universe is quantified in terms of $$\eta=\frac{n_B-n_{\bar B}}{n_\gamma}|_0= (6.21\pm 0.16)\times 10^{-10}\tag{1}$$ or $$Y_{\Delta B}=\frac{n_B-n_{\bar B}}{s}|_0=(8.75\pm ...
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Why does matter-antimatter asymmetry only refer to baryon asymmetry?
Why is the matter-antimatter asymmetry of the Universe quantified by the baryon asymmetry,
$$Y_B=\frac{n_B-n_{\bar{B}}}{s}$$
i.e., the difference in the number densities of baryons $n_B$ and ...
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1answer
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How can we assert $\mathrm{ matter } / \mathrm{ antimatter } \gg 1$ further than $locally$? [duplicate]
I read many hypothesis to explain the asymmetry between the quantity of matter and antimatter in the universe, most notably through
an asymmetry in initial baryogenesis. This assymetry would explain ...
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2answers
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How does inflation get rid of initial Baryon asymmetry (if any)?
Why is it said that even if the baryon asymmetry existed as an initial condition, the asymmetry would have been destroyed by inflation. How does inflation get rid of initial Baryon asymmetry (if any)?
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Consequence of C and CP-violation: What does it ensure and what it does not?
This question is a continuation of one of my earlier posts here and the accepted answer. Consider a two-body hypothetical decay $p^+\to e^+\gamma$ in a quantum field theory (say, a GUT). If the ...
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Difference between “C-violation without CP-violation” and “C-violation with CP -violation”
Consider two possible decay channels of a massive particle as $X\to A+B$ and $X\to C+D$ with decay rates $r$ and $1-r$ respectively. Let the decay rates of its antiparticle into channels $\bar X\to \...
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1answer
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Is proton decay considered in neutron star models (and LHC)?
Although it is definitely not simple, there are many reasons to consider that baryon number can be violated, for example:
during baryogenesis (just after Big Bang) there was created more matter than ...
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1answer
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Why both C and CP violation is necessary for baryogenesis?
Sakharov condition states both C and CP violation is necessary for baryogenesis. Now consider, for example, a theory with B-number violating interaction and C-violation. Therefore, if $p\to e^+\gamma$ ...
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Understanding the fine-tuning problem related to baryon asymmetry as an initial condition
The reason for not assuming the Baryon asymmetry of the universe as an initial condition is often attributed to the following fine-tuning problem: If the baryon asymmetry had been an initial condition,...
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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 \...
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Is this article about the SMASH hypothesis a fair assessment?
New Scientist is gushing as usual about a new development in physics. This one, called SMASH, looks truly interesting, though.
Apparently it's a small extension to the Standard Model that explains "...
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How do sufficiently energetic photons form electrons-positron pairs?
If the question seems strange, here's the wikipedia snippet that drives it:
The Big Bang theory is the most widely accepted scientific theory to explain the early stages in the evolution of the ...
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Possible intermediate scales of baryogenesis?
The conventional beyond Standard Model explanation of baryogenesis is that, within Grand Unified Theories (GUT), there exist some new heavy scalar bosons of mass $M_{\rm GUT}\sim10^{15}$ GeV, which ...
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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 ...
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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 ...
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Why do we believe baryon asymmetry?
The question is that how can we make sure that our universe is baryon asymmetric? I mean, is it possible that there are antimatter domains beyond some very large scale. Yes, if that kind of domains ...
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How many times does baryogenesis happen during the history of the universe?
Does the baryogenesis happen both in GUT epoch and electroweak Epoch during the history of the universe? If yes, are there any differences during this two times?
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Baryon / lepton number violation equivalence in Sakharov conditions
In the Sakharov conditions for matter-antimatter asymmetry the requirement for the baryon number violation is often interchanged with lepton number violation. In the context of the Sakharov conditions,...
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Baryon - Anti Baryon scattering
Is it possible, for a strong interaction of the above described type (baryon - anti baryon), to exist?
$$B + \bar B \to \ldots $$
(Where $B$ is a generic baryon and $\bar B$ the anti-)
Namely like ...
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1answer
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How was there an extra particle in the early universe?
According to theories.. In the early universe.. There were particles and anti-particles in equal number.. But there seems to be one extra particle against the number of anti-particles.. As the ...
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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 ...
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Asymmetry vs. Simple Statistics WRT Matter / Antimatter Ratios
I'm not clear on why physicists suspect, and are looking for, an asymmetry in nature that favors matter over antimatter. Here's a simple thought experiment to illustrate my confusion: Assume I have ...
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C&CP-Symmetry Violation in Baryogenesis
In cosmology, during the big bang; how does C-Symmetry violation allow for a greater number of baryons to be produced than anti-baryons in Baryogenesis, similarly how does CP-Symmetry tie into this?
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EW phase transition and baryogenesis
There are three Sakharov conditions of baryogenesis:
CP symmetry violation.
Baryon number conservation violation.
Thermodynamical equilibrium violation.
In SM the first one is satisfied by CKM ...
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Questions about the strange character of antimatter
Its been a few days and i have just been introduced to the concept of antimatter. Every Speck of matter in the world has its anti form basically that we have antimatter whenever we have matter. But I ...
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Few questions about SM baryogenesis
SM provides baryogenesis via leptogenesis due to anomalies and sphaleron processes. I have a few questions on it.
How exactly the anomalies in lepton and baryon currents provide convertation of ...
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How exactly sphaleron transitions erase initial baryon asymmetry, if any?
The sphaleron interactions in the Standard Model (SM) is $(B-L)$ conserving and $(B+L)$ violating. Each sphaleron transition causes the change in the baryon number $\Delta B$ and the lepton number $\...
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phase transition and effect on leptogenesis
What is the effect on leptogenesis in the standard model if the electroweak phase transition is (i) first order and (ii) second order?
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fate of a hadron in a big rip
As I understand it, if you try to "pull apart" a hadron with sufficient force, you just make more hadrons. Would the same thing happen in a Big Rip? (this answer suggests it would, as long as the ...
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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?
