did dark matter eat all the antiquarks?

[Nuke]

one thing that pops up in a lot of quantum physics documentaries is the mystery of where all the antimatter is. there should have been equal amounts of matter and antimatter. i think the consensus is that there was a small difference, annihilation happened, and what matter we see in the universe are the remnants.

then the other day i was reading about certain configurations of hexaquarks being a candidate for dark matter, specifically the one with 3 up quarks and 3 down quarks. i then went off on a tangent reading about other quark configurations. in pentaquarks i noticed that some included antiquarks as well. based on 45 minutes of reading wikipedia, i therefore hypothesize that an as of yet unknown hexaquark configuration, containing mostly antiquarks, is responsible for consuming the antiquarks from the early universe. perhaps matter is the leftovers from the event that created dark matter.  of course im sure people who are smarter than me (and understand qcd/qfd better than i do) have thought of this. 

[Nightside]

1 hour ago, Nuke said:

one thing that pops up in a lot of quantum physics documentaries is the mystery of where all the antimatter is. there should have been equal amounts of matter and antimatter. i think the consensus is that there was a small difference, annihilation happened, and what matter we see in the universe are the remnants.

then the other day i was reading about certain configurations of hexaquarks being a candidate for dark matter, specifically the one with 3 up quarks and 3 down quarks. i then went off on a tangent reading about other quark configurations. in pentaquarks i noticed that some included antiquarks as well. based on 45 minutes of reading wikipedia, i therefore hypothesize that an as of yet unknown hexaquark configuration, containing mostly antiquarks, is responsible for consuming the antiquarks from the early universe. perhaps matter is the leftovers from the event that created dark matter.  of course im sure people who are smarter than me (and understand qcd/qfd better than i do) have thought of this. 

Does a forum like count as peer review?

[Nuke]

3 minutes ago, Nightside said:

Does a forum like count as peer review?

no it does not, i just want to see what the real physicists think. 

[K^2]

I've never seen any indication of a stable, even remotely, particle with any quark count other than 3. And if stable arrangements exist for antiquarks, we should have ones with quarks as well. So we're still back to the question of why more of one than the other.

There are purely topological explanations for matter-antimatter imbalance as well. As a toy example, imagine our universe structured as an onion. Each moment of time is a shell, and inner shells happened "before" the later ones. Big bang is the point in the center of that onion. In that configuration, you don't have a question of what's before the big bang, because if you pass through the center, you start going to the future again, but on the opposite end of the universe. And you also don't have to have anti-matter. If all "matter" is radiated away from the center, all charges are conserved by what's happening on the opposite side of the universe. After all, the only difference between matter and antimatter is direction of propagation in time (to within TCP symmetry), and everything on the opposite side of the universe is propagating in the opposite direction. This simple model doesn't explain everything, but it's a start.

Yet other models allow for lepton families to oscillate beyond just flavor. So all the antiquarks are... electrons! Why we ended up with more of one less of another? Could be purely random. And there are other problems with these models, primarily because of predictions of supersymmetry that don't seem to pan out. But the point is, there are a lot of reasons the matter-antimatter imbalance could be. We shouldn't be coming with a theory to explain that. That's a sure way to lead yourself along the path of ad-hoc theory and confirmation bias.

[farmerben]

On 3/28/2020 at 2:16 AM, K^2 said:

I've never seen any indication of a stable, even remotely, particle with any quark count other than 3. And if stable arrangements exist for antiquarks, we should have ones with quarks as well. So we're still back to the question of why more of one than the other.

There are purely topological explanations for matter-antimatter imbalance as well. As a toy example, imagine our universe structured as an onion. Each moment of time is a shell, and inner shells happened "before" the later ones. Big bang is the point in the center of that onion. In that configuration, you don't have a question of what's before the big bang, because if you pass through the center, you start going to the future again, but on the opposite end of the universe. And you also don't have to have anti-matter. If all "matter" is radiated away from the center, all charges are conserved by what's happening on the opposite side of the universe. After all, the only difference between matter and antimatter is direction of propagation in time (to within TCP symmetry), and everything on the opposite side of the universe is propagating in the opposite direction. This simple model doesn't explain everything, but it's a start.

Yet other models allow for lepton families to oscillate beyond just flavor. So all the antiquarks are... electrons! Why we ended up with more of one less of another? Could be purely random. And there are other problems with these models, primarily because of predictions of supersymmetry that don't seem to pan out. But the point is, there are a lot of reasons the matter-antimatter imbalance could be. We shouldn't be coming with a theory to explain that. That's a sure way to lead yourself along the path of ad-hoc theory and confirmation bias.

That reminds me of a Feynman story.  Feynman was looking at how to include the Pauli Exclusion principle in his QCD.  Suddenly in a flash of insight he knew what explanation Wheeler would come up with.  Although Feynman doubted it was true, he wrote it down anyway and then went to go see John Wheeler.  In the course of their conversation Wheeler proposed the following theory:  

Electrons travel forward in time, anti-electrons travel backward.  The reason why two electrons cannot occupy the state is because there is only one electron!  A positron travels back and allows another version of the electron to travel forward again along a different path.  An almost unlimited amount of quantum states could be occupied by only one or a few particles oscillating between the past and future of the universe.  

At this point Feynman pulled out a piece of paper and handed to Wheeler.  Along with a few comments about wild assumptions, difficult to test, etc.    

 

[K^2]

1 hour ago, farmerben said:

Electrons travel forward in time, anti-electrons travel backward.  The reason why two electrons cannot occupy the state is because there is only one electron!  A positron travels back and allows another version of the electron to travel forward again along a different path.  An almost unlimited amount of quantum states could be occupied by only one or a few particles oscillating between the past and future of the universe.

There is a common statement that protons and neutrons are made up of 3 quarks. That's not actually the case. Both of these are actually a soup of quarks and fermions. But if you take a snapshot of the proton or neutron at any given time and start matching up particles with anti-particles they could annihilate, you'll be left over with 3 quarks. These are called valence quarks and they're always there. You can't say that it's these three specific quarks over there, because that's purely arbitrary, but in the count, there will be 3 left over. Well, what about all the other particles? A lot of them really are just these three valence quarks bouncing back and forward in time! And in fact, there are only two possibilities for a lone particle. Either any given particle is part of that valence quark trajectory, or it's part of a loop. And loops are even weirder, because it's one particle on a closed trajectory that covers some stretch of time resulting in interactions as if it was a whole bunch of particle and anti-particles, returning to the exact point in space and time where it started.

What makes all of this a lot worse is that no particle takes just one trajectory. Each particle moves along every possible trajectory, meaning we can't say for sure if a particle is part of a loop or a valence trajectory. It can be both. One of Feynman's important contributions was the mathematical description of this fact as part of path integral formalism.

At some point, you're really forced to accept that the very idea of a "particle" is just us trying to assign familiar properties to unfamiliar math, not unlike people of antiquity assigning human personalities to forces of nature. It's still convenient for making some explanations easier to follow, and Feynman's diagrams are a fantastic tool for sorting through math, but you can only take the particle analogies so far before it breaks down, and it's something you have to be careful with.

Edited March 31, 2020 by K^2

[wumpus]

On 3/31/2020 at 4:42 PM, farmerben said:

That reminds me of a Feynman story.  Feynman was looking at how to include the Pauli Exclusion principle in his QCD.  Suddenly in a flash of insight he knew what explanation Wheeler would come up with.  Although Feynman doubted it was true, he wrote it down anyway and then went to go see John Wheeler.  In the course of their conversation Wheeler proposed the following theory:  

Electrons travel forward in time, anti-electrons travel backward.  The reason why two electrons cannot occupy the state is because there is only one electron!  A positron travels back and allows another version of the electron to travel forward again along a different path.  An almost unlimited amount of quantum states could be occupied by only one or a few particles oscillating between the past and future of the universe.  

At this point Feynman pulled out a piece of paper and handed to Wheeler.  Along with a few comments about wild assumptions, difficult to test, etc.    

 

I liked the story about "positrons travel backward" enough that I had to ask if enough had been assembled to observe entropy.  Alas, entropy was moving in the right direction: no "Practice effect" anti-matter for us.

https://www.goodreads.com/book/show/101893.The_Practice_Effect

[Nuke]

antimatter goes backwards makes me think about negative time. could an antimatter big bang be going off in the direction of negative time while antimatter goes in forward time? one big bang causes 2 universes expanding in opposite time directions?

Edited April 2, 2020 by Nuke

[K^2]

6 hours ago, Nuke said:

antimatter goes backwards makes me think about negative time. could an antimatter big bang be going off in the direction of negative time while antimatter goes in forward time? one big bang causes 2 universes expanding in opposite time directions?

Both matter and antimatter have positive energy, so they move along the same trajectories in space-time - just in opposite directions. So the fact that the universe is expanding at an accelerating rate pretty much excludes that possibility.

[MinimumSky5]

But if antimatter could travel backwards in time, then either: 

Causality cannot be conserved, as antimatter particles would constantly be arriving from future high energy events

Or:

Antimatter could not be seen, as it would immediately start moving at a right angle to our conventional four dimensions of spacetime, and would appear to just vanish from existence at its point of creation.

Or, am i just missing something here?

[farmerben]

From our perspective we can generate a flow of positrons from radioisotopes, separate the positrons from electrons and direct them with electromagnetic forces into targets.  The targets can be anything.  The sources are things like K40 and Kr79.  Antimatter certainly has positive mass and travels less than the speed of light.  

It is unknown (at least to me) whether the mass of positrons and electrons actually differs.  The mass of neutrinos (as of last I knew) was not fully pinned down.  If their masses differ antimatter could have been hurled to the edges of the universe.

Particles could be moving away from us faster than the speed of light beyond the edge of the visible universe.  Hyperinflation of space and dark energy allow particles far apart to travel faster than the speed of light.  So if antimatter were just a wee bit lighter... it could be mostly beyond our horizon.  

[HebaruSan]

3 minutes ago, farmerben said:

antimatter could have been hurled to the edges of the universe.

Particles could be moving away from us faster than the speed of light beyond the edge of the visible universe.  Hyperinflation of space and dark energy allow particles far apart to travel faster than the speed of light.  So if antimatter were just a wee bit lighter... it could be mostly beyond our horizon.  

Doesn't that assume that it all would have originated in our current vicinity? I thought in cosmology things generally happened everywhere all at once, so we would still see antimatter from other regions.

[kerbiloid]

We need neutrinoscopes.

Antinuclear processes should generate a reversed ratio of neutrinos and antineutrinos.

P.S.
In KSP, too. We need them.

Edited April 3, 2020 by kerbiloid

[K^2]

21 hours ago, HebaruSan said:

Doesn't that assume that it all would have originated in our current vicinity? I thought in cosmology things generally happened everywhere all at once, so we would still see antimatter from other regions.

Well, all of the universe started as a single point, or as close to one as we could tell. If so, then if there was a statistical imbalance between matter and antimatter very, very early in the inflation, you could, in principle, end up with matter and antimatter being separated by immense distances once things settle down. I don't really know enough about the inflation to say whether it'd be possible for all the antimatter to end up beyond the boundaries of visible universe. I think, all of the cosmological models assume visible universe = universe, but that's probably only because due to how universe was expanding, nothing that's currently outside of the visible universe could ever have been part of visible universe except, possibly, really, really, really early on, and it means it couldn't have impacted evolution of visible universe, so we can pretend nothing outside visible universe exists without getting any disagreements with experiment. If nothing in our understanding of cosmology contradicts the notion that universe >> visible universe, as in greater by a lot, then I can't think of any reason why it couldn't be that all the antimatter is simply beyond the boundaries of the visible universe. But this stretches my understanding of cosmology past the breaking point, and I don't even know any cosmologists to ask. We had one theoretical astrophysicist in our department, and she specialized in neutron stars.

[kerbiloid]

Brief version: nobody has an idea.

Upd.
See above about the neutrinoscopes. Until we have them, we can only speculate.

Upd 2.
When we get them, this doesn't necessary mean the picture will get clear. But at least then we can see if there are antimatter regions in the visible Universie.

Edited April 4, 2020 by kerbiloid

[farmerben]

On 4/3/2020 at 2:17 PM, K^2 said:

 I think, all of the cosmological models assume visible universe = universe, but that's probably only because due to how universe was expanding, nothing that's currently outside of the visible universe could ever have been part of visible universe except, possibly, really, really, really early on, and it means it couldn't have impacted evolution of visible universe, so we can pretend nothing outside visible universe exists without getting any disagreements with experiment. If nothing in our understanding of cosmology contradicts the notion that universe >> visible universe, as in greater by a lot, then I can't think of any reason why it couldn't be that all the antimatter is simply beyond the boundaries of the visible universe. But this stretches my understanding of cosmology past the breaking point, and I don't even know any cosmologists to ask. We had one theoretical astrophysicist in our department, and she specialized in neutron stars.

 

I would operationally define words this way.

universe = a 4 dimensional continuum (our space-time)

light cone universe = the entire visible universe including those points where light is blocked or altered by material

extended universe = those points in our space-time from which light cannot reach us because anything there is moving away from us faster than the speed of light

 

I think we have a curtain of cosmic microwave background radiation at the edge of our visible universe.  This is from roughly the moment when the universe became a mostly transparent nebula.  This was probably 350,000 years after the big bang.  Before that we think a high energy plasma filled the universe.  So the light cone universe extends beyond the visible universe into this high energy plasma.  

I don't have a solid theory of hyper-inflation.  But one hypothesis states that matter at the edges of our universe will keep accelerating away from us into our extended universe.  The quasars and eventually all the galactic clusters except our own will escape into our extended universe.  

The multi-verse is more than one space-time existing discontinuously.  However a light cone universe and an extended universe can make up one continuous whole.  

Edited April 6, 2020 by farmerben

[K^2]

On 4/6/2020 at 3:17 PM, farmerben said:

extended universe = those points in our space-time from which light cannot reach us because anything there is moving away from us faster than the speed of light

Interestingly enough, speed of light isn't the problem. If universe wasn't expanding at an accelerated rate - even if expansion was constant and FTL, you'd still be able to reach every part of the universe eventually. It seems counter-intuitive, but because space itself is expanding, the fact that something is retreating from you at FTL speeds doesn't prevent you from catching up eventually. That's because as you travel forward, you'll be making progress at an inverse rate to the elapsed time, meaning that total time to reach destination is not infinite, but actually exponential. Consequently, if universe continued to expand at constant rate, it would take much, much longer than current age of the universe to reach the edge of visible universe, but you'd be able to do that in finite time and to even go past it.

However, all indication is that universe is expanding at an accelerated rate, and that means that there are parts of the universe we can see right now, but will never be able to reach without figuring out FTL means of travel. A light signal we would send in that direction would never reach its destination.

[farmerben]

Accelerating at relativistic speeds adds another factor of distance to time dilation.  In the twin paradox, each percieves the other as slowed down.  The twin who accelerates and changes direction sees the other race ahead, during the acceleration phase only, then go slowly during the return cruise.  Taking the same twin journey and turning around at a more distant point, makes the time leap greater.  

 

If the universe is hyperinflating ( third derivative of x is positive) there could be another effect I'm not sure.   I wonder if anybody knows a good lecture series about it.