Questions tagged [baryogenesis]
The baryogenesis tag has no usage guidance.
77
questions
6
votes
0answers
31 views
Amount CP violation needed
It is widely known that the CP violation provided by the Standard Model ( SM )is insufficient to explain the baryon asymmetry that we observe. However, I never came across any quantitative ...
0
votes
1answer
65 views
Big bang should have made up an equal amounts of both matter and anti matter, then why don't we see such?
So, my question arises that how do we know that normal matter is more in quantity or number than anti-matter? Research at ALPHA said that anti-matter that the spectrum of hydrogen and anti-hydrogen ...
2
votes
0answers
37 views
Positrons in space, are they remnants of baryon asymmetry?
This recent paper
By observing 1.9 million positrons (out of 107 billion cosmic rays), the AMS Collaboration finds that the energy dependence of the positron flux is very complex.
...
Overall, the ...
0
votes
2answers
69 views
How come positrons don't destroy all the electrons in the universe?
What it says on the title. How come all the positrons don't destroy all the electrons in the universe and vice versa? They are attracted to each other due to opposing charges.
1
vote
1answer
33 views
Could it be that at the big bang equal amounts of matter and antimatter were created, but the antimatter got stuck in black holes? [duplicate]
I recently watched PBS spacetime's video series on the black hole information paradox. Where they first discussed the no hair conjecture and then later also the true destruction of information by ...
1
vote
1answer
111 views
Could there be a region of the universe that is dominated by antimatter?
I was reading some texts explaining that since our region of the world is overwhelmingly dominated by matter, and not by anti-particles, this suggests that in some region of the universe, there will ...
2
votes
3answers
82 views
Why is there matter when all of it should have annihilated with antimatter?
The theory is that after the Big Bang, photons turned into matter and antimatter particle pairs, but they should have all annihilated with each other. Since there would be an equal amount of matter ...
3
votes
3answers
69 views
How does the baryon asymmetry control temperature fluctuations of CMB?
The temperature fluctuations of the Cosmic Microwave Background (CMB) have a sensitive dependence on the quantity of baryon asymmetry of the universe. In fact, analysis of CMB fluctuations is one of ...
0
votes
1answer
60 views
Why more matter than antimatter and if so, how do we know this?
firstly, how do we know this? and secondly, would it not be possible that either antimatter and matter were produced in separate regions or randomly and if randomly it makes sense that in any given ...
0
votes
0answers
34 views
Experimental evidence of interaction out of thermal euilibrium?
Sakharov gave three conditions for the matter-antimatter asymmetry observed in the universe.
(1) Baryon number violation: Don’t have any experimental confirmation yet.
(2) C-symmetry and CP-symmetry ...
49
votes
4answers
8k views
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 ...
2
votes
1answer
130 views
What if there were only 1 generation of fermions?
The number of fermion generations has many effects beyond the mere existence of "3 copies of fermions," including determining scatterings, constraining CP violation, influencing electroweak symmetry ...
1
vote
1answer
330 views
Why is baryon number conservation an accidental symmetry
I have to write a report surrounding the subject of baryogenesis and I wanted to start this report off with explaining how the first Sakharov condition: Baryon number violation is possible within the ...
3
votes
1answer
93 views
How does the CMB constrain the baryon asymmetry?
The CMB contains information about baryon acoustic oscillations in which baryons (I assume protons and electrons) and photons form a plasma exhibiting sound waves. How is information about the baryon ...
5
votes
1answer
222 views
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 ...
0
votes
1answer
111 views
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 ...
0
votes
3answers
94 views
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 ...
2
votes
1answer
77 views
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 ...
0
votes
1answer
126 views
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 ...
3
votes
1answer
115 views
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 ...
4
votes
2answers
162 views
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 ...
4
votes
0answers
207 views
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 ...
2
votes
1answer
160 views
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 ...
0
votes
1answer
50 views
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?
3
votes
1answer
177 views
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 ...
1
vote
1answer
135 views
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
$$Y_B=\frac{n_B-n_{\bar{B}}}{s}=\frac{n_B}...
1
vote
0answers
46 views
Could baryon asymmetry be negative?
In the paper http://hamilton.uchicago.edu/~harvey/pdf_files/harvey_turner_1990.pdf,
it can be seen from expressions (9a, 9b,9c) that barygon asymmetry is proportional to negative lepton asymmetry. But ...
-1
votes
3answers
65 views
Is the gravitational pull of the early ($10^{10}$ more massive) universe still observable?
During one of the early epochs of the universe it used to be 10^10 times more massive than it is now, just before the matter / antimatter annihilation. So what cosmic gravity is being asserted on the ...
14
votes
2answers
1k views
If all the Structure in our visible Universe originated from Quantum Fluctuations, why isn't there as much Anti-Matter as Matter?
According to inflation, all the structure that we see like galaxies, etc. originated from quantum fluctuations which were expanded during inflation. But since quantum fluctuations always create ...
0
votes
1answer
149 views
Why is the quantum number $\frac{1}{3}B-L_\alpha$ said to conserved in the Standard model rather than $B-L$?
In the standard model, the baryon number $B$ and the lepton number$L$ are conserved perturbatively. However, the B+L quantum number is anomalous and is violated via non-perturbative effects while ...
0
votes
3answers
169 views
Number excess of baryons per antibaryon in a comoving volume: Interpreting $Y_{\Delta B}$ in the present epoch
The baryon asymmetry of the Universe is quantified in terms of $$\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 ...
3
votes
2answers
236 views
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 ...
0
votes
1answer
108 views
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 ...
3
votes
2answers
310 views
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)?
...
2
votes
0answers
144 views
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 ...
5
votes
1answer
278 views
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 \...
5
votes
2answers
370 views
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 ...
5
votes
1answer
561 views
Why are both C and CP violation 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 $p\to e^+\gamma$ ...
5
votes
2answers
202 views
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,...
8
votes
1answer
385 views
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 \...
4
votes
1answer
165 views
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 "...
4
votes
2answers
899 views
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 ...
1
vote
0answers
45 views
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 ...
12
votes
1answer
392 views
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 ...
8
votes
1answer
212 views
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 ...
1
vote
1answer
427 views
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 ...
2
votes
0answers
62 views
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?
2
votes
1answer
137 views
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,...
1
vote
1answer
97 views
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 ...
1
vote
1answer
76 views
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 ...
