Talk:Baryogenesis

message: Do the equations underlying the analysis of Baryogenesis implicitly assume a FLAT spacetime?  What if the Cosmos is CLOSED, so that the early universe was a highly curved hyper-sphere ("Sphereland" in 2D).  Such a highly curved spacetime fabric would be ASYMMETRIC, w/ pronounced differences between the "inside edge" of the hypersphere, and its "outside" (especially if, as seems reasonable, spacetime has some "thickness" in the extra hyperspace dimension).  Could such an asymmetry help explain the asymmetry of matter vs. anti-matter ??  —Preceding unsigned comment added by 66.235.26.150 (talk) 08:22, 7 May 2010 (UTC)
thread_title: Baryogenesis in Ultra-Curved Spacetime of early Closed Cosmos

message: Technically, this translates as the commutator of the baryon number quantum operator with the Standard Model hamiltonian operator is zero: [B,H] = BH - HB = 0.
:It's not, you know. Instantons change the baryon number. Phys 14:08, 18 Jan 2005 (UTC)
thread_title: Baryon number conservation

message: What if are definitions of matter and anti-matter are wrong?
Let us redefine matter and anti-matter based on charge, matter is positively charged and anti-matter is negatively charged. We then get the following:
Matter
Positron
Up quark
Anti-matter
Electron
Down quark
A proton would now consist of 2 parts matter and 1 part anti-matter.
A hydrogen atom would now consist of 2 parts matter and 2 parts anti-matter.
As you can see the asymmetry has vanished, matter and anti-matter are distributed equally throughout the universe.
—The preceding unsigned comment was added by 82.42.190.64 (talk • contribs) .
* That doesn't make any sense. The down-quark clearly isn't the antiparticle of the up-quark. Antiparticles aren't some arbitrary definition, they are an immediate consequence of Quantum Field Theory, which is the most successful description of nature that we have. 142.3.164.195 22:07, 12 May 2006 (UTC)
replies: text: I'm not implying that the down-quark is the anti-particle of the up-quark. I was saying what if all positively charged particles are really matter and all negatively charged particles are anti-matter, then positrons, up-quarks and anti-down-quarks would be considered as matter, while electrons, anti-up-quarks and down-quarks would be considered as anti-matter.GoldenBoar 03:01, 23 August 2006 (UTC)
replies: text: In that case protons would not be stable and would self-annihilate, due to the negatively-charged down quark and positively-charged up quarks.  Obviously that doesn't happen.  Not to be rude, but you might learn something by reading a standard reference textbook on particle physics (e.g. Griffiths, Introduction to Elementary Particles, or one of the many others). —The preceding unsigned comment was added by 142.104.60.203 (talk) 00:33, 20 March 2007 (UTC)
replies: text: I think he's just proposing a name change, declaring by fiat that the positively charged member of a particle/antiparticle pair be the one considered "matter". The problem, other than trying to overturn the existing definition, is that you still have the asymmetry (we see lots of electrons but no positrons, whichever one is considered "matter" or "antimatter"). --Christopher Thomas 00:43, 20 March 2007 (UTC)
replies: text:  OK, certainly, you could make all the name changes you like, but you wouldn't change the physical baryon asymmetry of the universe (or whatever you change that name to) -- it's a meaasurable (and measured), not a gauge-dependent, quantity. I propose not announcing on the arxiv that a few jerks on Wikipedia have changed the definition of matter and antimatter. :) 142.104.60.203 07:18, 25 August 2007 (UTC)
thread_title: Definitions of matter and antimatter

message: "The exact experimental value involves measuring the concentration of chemical elements in the universe not originating from stellar synthesis."
The above sentence needs to be repaired.  Michael H 34 17:56, 16 August 2007 (UTC)
thread_title:  Please review 

message: In the phrase "where the conservation of baryon number is broken perturbatively" it isn't clear to me what perturbatively means.  Is it possible to clarify that?  77.100.103.108 (talk) 04:49, 8 October 2008 (UTC)
replies: text: It means that one uses perturbation theory to dig out the results. Figuratively, you write the phenomenon in a very simplistic model and then you assume that the "interesting" part behaves as a small effect displacing the simple model, and see what comes out of such simple + perturbation model.  —Preceding unsigned comment added by 193.126.230.50 (talk) 10:39, 30 November 2010 (UTC)
thread_title:  Word unclear (to me) 

message: Does "cubic kelvin" actually mean anything?  How do you cube such a unit?
Soronel (talk) 06:09, 4 September 2009 (UTC)
thread_title:  Cubic Kelvin 

message: In the Background section of the article, one of the "points of view" given to support the idea that the universe was originally perfectly symmetric is: "if the universe encompasses everything (time, space, and matter), nothing exists outside of it and therefore nothing existed before it, leading to a total baryonic number of 0." I tagged this as needing a citation, but Headbomb removed that tag , saying that "nothing = 0" is obvious. My reason for adding the tag is that I question whether a statement about what exists "outside" or "before" the universe is a valid scientific claim. It seems intuitive, in some sense, that "nothing" should imply a baryonic number of 0, I suppose, but is this an actual, meaningful idea that we can ascribe to a reliable scientific source, or is this just a hand-wavy pseudo-explanation invented by some Wikipedia editor to appeal to intuition? (I don't have any knowledge about particle physics or cosmology, so I don't know the answer to this question—that's why I asked for a citation.) —Bkell (talk) 06:22, 3 December 2010 (UTC)
replies: text: It's pretty much the explanation any particle physicist would give you for this. If you have n baryons and m antibaryons, you have a baryon number of n − m. If you have nothing, then you have no baryon/antibaryons (n = 0, m = 0), thus n − m = 0 .  It would be pretty hard to find this specific claim in books, simply for the reason that no one probably ever bothered to write this down.  Not saying it's impossible to find one, but it's not something that warrants a "citation needed" tag. Headbomb {talk / contribs / physics / books} 06:58, 3 December 2010 (UTC)
replies: text: Okay, sure, if a system has no baryons and no antibaryons then the system has a baryon number of 0, I agree. But what's the basis for the belief that "nothing" existed before the Big Bang (or before the Planck epoch or whatever)? Is it even meaningful to discuss what existed before then? Is there even a "before then" to discuss? The article presents this "nothing before the Big Bang" idea as a reason for the belief that the universe started out in symmetry and then something happened to break it. If this "nothing before the Big Bang" idea really is the reason that (most? many? some?) scientists believe that the universe began in symmetry, then we should be able to find a reliable source that gives this idea as a reason for this belief and hopefully clarifies what the idea means. Otherwise, claiming it as justification seems to me to be unsupported speculation or hand-waving, especially if "before the Big Bang" and "outside the Universe" are physically meaningless phrases. —Bkell (talk) 09:06, 3 December 2010 (UTC)
replies: text: Hence why the whole thing is prefaced with "If the universe emcompasses everything". The idea being conveyed here is that if you start with nothing, then you have no net baryon number. Wheter it's even meaningful to even speak of a start is best left to philosophy (see Newton's Flaming Laser Sword). Headbomb {talk / contribs / physics / books} 09:27, 3 December 2010 (UTC)
replies: text: Well, the chain of reasoning "There was nothing before the Big Bang, therefore the baryon number of the Universe was 0, and therefore the baryon number of the Universe just after the Big Bang must have been 0 too" seems either very naive or very profound. It certainly does not seem to be a self-evident postulate to me, because it's based on so many premises that appear to be meaningless. Look, I'm not arguing either for or against that reasoning—I just want a citation to a reliable source, so that I can confirm that it isn't something completely naive that some Wikipedia editor just made up. —Bkell (talk) 18:14, 3 December 2010 (UTC)
replies: text: The claim is not that there was nothing before the big bang, therefore the baryon number is zero, but rather if there were nothing before the big bang, then the initial baryon number is zero per definition of what nothing and zero  means. This is as deep/naive as saying an empty bag contains zero apples (or oranges, if you prefer oranges). Headbomb {talk / contribs / physics / books} 16:08, 15 December 2010 (UTC)
replies: text: Look, I'm not disputing that "nothing" means "baryon number is zero"—what I am saying is that it is not at all clear to me that the "nothingness" before the Big Bang (which itself is a statement that seems to have no meaning) should have any relation at all to the situation after the Big Bang. Why should it be the case that the Big Bang preserved baryon number? As I understand it, the paragraph under discussion here says that there are (at least) two possibilities: (a) the Big Bang itself created more matter than antimatter, or (b) the Big Bang preserved the baryon number of "nothingness" and something else later, baryogenesis, caused matter to predominate. The whole point of the paragraph is that possibility (b) is "preferred" because there was "nothing" before the Big Bang. But that doesn't explain anything—isn't possibility (a) also fine if there was "nothing" before the Big Bang? What possible reason do we have to believe that the Big Bang preserved baryon number? Assuming that the baryon number of the Universe before the Big Bang was zero (again, I can't see how this is a meaningful statement, but whatever), why is it more likely that some mysterious "baryogenesis" process was responsible for the current predominance of matter over antimatter, rather than the Big Bang itself? Any argument that the Big Bang should have preserved baryon number (so that the baryon number of the Universe immediately after the Big Bang was zero, thus requiring a separate process of baryogenesis) based on the argument that there was nothing before the Big Bang seems to be very naive and baseless, and possibly even fallacious. Either that or I am missing something very deep (not just that "nothing" means "baryon number is zero"), which is possible because I don't really understand this stuff. We need a citation to a reliable source to show that this reasoning (not just "nothing means zero baryon number") is commonly accepted as sound, or at least plausible, in the scientific community. That's what I'm saying. —Bkell (talk) 17:55, 15 December 2010 (UTC)

text: By the way, I do appreciate your responses. They have certainly helped me to clarify my thinking—I think the argument I was making at the beginning of the discussion was a lot murkier and less targeted than the argument I'm trying to make now. —Bkell (talk) 18:04, 15 December 2010 (UTC)
replies: text: I know this is an old discussion but I got annoyed at the hard time that Bkell was given to get an apparently pretty simple (for somebody with a background in physics or mathematics) point across, while the actual argument he/she was trying to make was totally ignored. Taking the empty bag example, the point (as I read it) is that if you don't even have a bag then you cannot justify saying that this non-existent bag has zero apples. In fact, if we follow the mathematical convention that makes the most sense when talking about non-existent things (empty sets), any statement about the non-existent bag should be considered true (and for people without mathematical background this isn't at all intuitive or naive). For the universe this means that if the universe did not exist before the Big Bang, then its baryon number would have been 42 (or whatever else you want it to be) before the Big Bang. And there is absolutely no contradiction here with a baryon number of 0 for an existing universe; that would be like comparing apples and oranges...  110.23.118.21 (talk) 09:39, 25 January 2016 (UTC)
thread_title:  Nothing = 0? 

message: As I understand it, the recent theory of two universes being created together with zero entropy going in oposite time directions could easily answer the barion-antibarion asymetry. 
* Two universes are created coincidently both having zero entropy initially.
** One universe has increasing entropy in (what we percieve as) the forward time direction
** The other has increasing entropy in the other time direction
* Baryons move forward in time (as wer percieve time). All baryons that were created close enough to time zero end up in our universe.
* Antibaryons move in the oposite time direction. All antibaryons that were created close enough to time zero end up in the other universe.
The movement (expansion) of the universe "forward" in time quickly eliminates the ability to communicate with the other universe (execpt posibly by gravitational influences).
18:12, 30 July 2015 (UTC)
thread_title:  Two Universes 

message: http://www.dailygalaxy.com/my_weblog/2015/09/missing-antimatter-of-the-universe-mystery-solved-weekend-feature.html
Worth a mention? Hcobb (talk) 03:53, 14 September 2015 (UTC)
thread_title:  Magnetic twist 

message: It's not clear to me why some theories are in this article and some are in the Baryon asymmetry article. Should the two be merged, or content moved between them?
Jruderman (talk) 23:48, 12 January 2017 (UTC)
thread_title:  Merge with Baryon asymmetry