The Baryogenesis Anomaly: What happened to all the Antimatter?

CHAPTERS:
0:00 - What is the anomaly?
2:12 - Special offer for AA viewers
2:57 - Best theories in physics
3:46 - Why is there something instead of nothing?
5:57- Matter-antimatter creation
7:16 - Baryogenesis
8:12 - Sakharov conditions
9:15 - C and CP symmetry
11:23 - Weak force violates CP
12:02 - Baryon conservation
13:01 - Theories on matter antimatter asymmetry

SUMMARY:
Why are we here? Why is there something instead of nothing. Part of the answer is rooted in physics. Matter is not the simplest thing there could have been. The simplest thing In physics is nothing, the emptiness of spacetime. So why isn’t the entire universe made of nothing? According to physics, that's what the universe should be made of, because whenever matter is created, an equal amount of antimatter is also created. But when matter and antimatter meet, they annihilate each other leaving nothing. But for some reason almost everything in the visible universe is made of matter. What happened to all the antimatter?

The Standard model and general relativity do not account for how we got so much matter and almost no antimatter.
First, how did something come from nothing? With quantum mechanics, this “problem” has a workable solution. Nothing, or empty space has quantum fluctuations. Virtual particles are created and destroyed everywhere all the time. Empty space has energy, it can exert a force as can be seen in the Casimir effect. But when matter is created, antimatter is also created which annihilate each other. Antimatter is just like matter, except with the opposite charge.

But, we would expect to see just as much antimatter as we do, matter. But we see only matter. What could have caused this matter antimatter asymmetry? This issue is called the problem of Baryogenesis, which is the physical process in the early universe which caused the imbalance between matter and antimatter.

Russian nuclear physicist Andrei Sakharov proposed that the universe must satisfy 3 conditions in order to create matter and antimatter at different rates.
1. The universe must be out-of-equilibrium
2. The universe must exhibit C and CP symmetry violation
3. Universe must have baryon-number-violating interactions.

The first condition is easy to meet because we live in a universe that is cooling and expanding. It is not in equilibrium.
C symmetry stands for charge conjugation symmetry. It just means that the laws of physics should apply just as equally to antimatter as they do for matter. The weak force breaks C symmetry all the time. This is because neutrinos and antineutrinos only have one type of spin.

CP symmetry is the combination of C symmetry and P symmetry. P stand for parity. This means mirror image. Parity in the context of particles can represent spin, so a particle with a clockwise spin would rotate counter-clockwise for example.

The weak force has processes that violate the CP transformation and thus the CP symmetry. For example K, B and D mesons, which are particles made up of one quark, and one antiquark, can violate CP symmetry when they decay. But there are not enough CP violating interactions to explain the difference in the amount of matter and antimatter volume.

The last condition about Baryon conservation is also a problem. A baryon is a particle composed of 3 quarks. In general, you cannot destroy Baryons, you can only change them. For example, in beta decays a neutron can turn into a proton and vice versa. In order to satisfy the 3rd Sakharov condition, we would need a process such that can make 2 baryons from 1 baryon. We’ve never observed this happening.

So the question remains, what caused the matter-antimatter asymmetry. There are some speculative theories.
#baryogenesis
#matterantimatterasymmetry
One theory is from what Richard Feynman said - that antimatter is mathematically equivalent to ordinary matter moving backwards in time. So perhaps at the Big Bang, antimatter started going backwards in time and never encountered matter. Maybe the universe “banged” in two opposing temporal directions. The problem with this hypothesis is that antimatter that we observe all goes forward in time, not backward.

Some say that there might be mirror antimatter galaxies in distant parts of the universe. But if this was the case, we would expect to see some high energy gamma rays from the border areas where matter objects encountered antimatter objects. Nothing like this is being observed.

One way we may find out is by studying the gravitational wave background, but our instruments are not powerful enough to detect this.

[infantry]

Your videos explains things well. For that, I thank you.

I may always be an average joe that didn’t even finish college, and will very, very likely never be a physicist, but I love looking up at the night sky in wonder, while trying to grasp our place in it. You make these topics so incredibly accessible to people, and I can’t even begin to imagine how many young (and old!) minds you are inspiring with your passion, and your love and drive to share your knowledge. Thanks again— and please keep at it!

[DM_Curtis]

What happened to anti-matter? I don't know -- go ask uncle-matter!

[programmingpython]

Your way of teaching is on the next level

[Grandunifiedcelery]

As promised, Arvin is marvelous! I could not always understand the first of the Sakharov conditions, the out-of-equilibrium, but only with the brief explanation of Arvin.

[ManuelGarcia-cdhk]

Arvin Ash and Dr PhysicsA are the clearest explainers of science in the Internet.

[danerman]

Arvin Ash is very good at explaining complex subjects in physics. Loved this video, matter antimatter asymmetry is one of the great mysteries of the universe. Of course we would not be here without it.

[ukno]

Thank you, Arvin! Great video and explanation as always 👏

[mariodistefano]

He's way to teach is almost unique, and makes all he says, crystal clear! Thanks Arvin!

[BillyMcBride]

I can tell that you and your team worked hard on this video. Keep up the good work.

[k.k.]

Very nice video essay. If I may add, your explanations on CP violation and the antimatter time-reversal would have perfectly connected to CPT symmetry, or its violation. Furthermore the deep connection of CPT symmetry to the standard model of physics via Lorenz invariance emphasizes the now very often used expression of physics beyond the standard model. I.e. the standard model of physics being right, but part of a bigger theory. A follow up video on that would suit really nicely

[luisenriquecharon]

Excellent video! What about T and CPT violations and their impact on the Standard Model and the Theory of General Relativity?

[mike]

I don't understand why Arvin's videos aren't more widely watched. Just here to push the algorithm.

[invictus]

Dude, I'm giving this a thumbs up just for the phonetic eloquence of "baryogenesis anomaly"...

[notenoughyettoomuch]

Whenever I feel depressed I know I can come to your channel and enjoy myself. Thank you

[nicoblack]

“Fall in love with some activity, and do it! Nobody ever figures out what life is all about, and it doesn’t matter. Explore the world. Nearly everything is really interesting if you go into it deeply enough. Work as hard and as much as you want to on the things you like to do the best. Don’t think about what you want to be, but what you want to do. Keep up some kind of a minimum with other things so that society doesn’t stop you from doing anything at all.” Richard Feynman

[clarkh]

Awesome video! Thank you Arvin, take care brother. The next generation is lucky to have you, and your videos.

[alleneverhart]

Hi Dr. Ash, I think we have given up too easily on the rapid separation explanation. If there was a slight overabundance of matter in 1/2 of the universe just prior to inflation then net matter would have been separated from antimatter faster than the speed of light. The boundary areas where we expected to see m/a annihilations all occurred during the period before recombination. As fantastically improbable that such an overabundance configuration is, if we consider that the universe is infinite, which recent examination of the CMB says is likely, then, such regional departures from average nothingness become inevitable and magnified by inflation. Which, unfortunately, is a sort of an anthropomorphic solution unless we can peer into the period of time before recombination to see something.

[chandrasekharpbg]

"coming up.. right now" so pleasing to hear from you every time 👌

[scyphe]

From what I've read (and you explained in your video), matter and antimatter are both self-attractive, yet matter and antimatter mutually repel each other. That could explain why there's no antimatter in our matter-centric universe. Antimatter and matter (what was left from a possible matter<>antimatter annihilation period taking place early during the early era of the universe) may have clumped due to their self-attractive properties. Meanwhile matter and antimatter kept repelling eachother and at some point as early as pre-star formation possibly completely separated, moving away from each other. There may be an antimatter twin universe somewhere far away from our matter-based universe which is why we never see any trace of any sizeable antimatter objects.

It would be interesting to learn a theory on how/whether an antimatter universe could work. It would obviously require a revision of everything we know about physics today to understand the behavior of antimatter in a space devoid of matter.

[robertschlesinger]

Excellent video, as always. Very interesting, informative and worthwhile video.