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Matter, Anti-Matter, and a New Subatomic Particle?
sciencehabit writes "Physicists may have finally figured out why the universe contains more matter than antimatter. The key lies in a flaw in the relationship between the two and a potentially new subatomic particle. 'Other researchers, however, say the results, published today in Nature, should be interpreted cautiously. It could all be an effect produced by run-of-the-mill particles'."
IIRC dark matter is required to make the observed rotation of galaxies fit our current model. OTOH: When I was a kid in the 60's black holes were mathematical curiosities.
And did you exchange a walk on part in the war for a lead role in a cage? - Pink Floyd.
A flaw in our understanding of it. Quit making flames for the sake of making flames because there is no basis in the article for what you said. You'll look less stupid in the process.
this nation, under God, shall have a new birth of freedom. -- Lincoln, Gettysburg Address
So did Garrett Lisi predict the new particles? Do they fit into the E8 algebra thing that his theory is based on?
Without this "flaw" matter and anti-matter would have cancelled out almost perfectly early on in the Big Bang leaving nowhere near enough matter (or anti-matter) to form galaxies or stars. So this "flaw" is what allows us to exist. I would not call it a flaw, but rather a design feature. Without breaking this symmetry the Universe would be a really boring place, in much the same way that a tree is more interesting than a cube even though the cube has far more symmetry.
I agree there is "something" out there that does have mass and therefore also has gravitational fields.
Since we can't currently *see it* I'll also agree that because it is currently not directly observable it is therefore "Dark" and made of "Matter".
My point is; that it to call it "Dark Matter" and to be done with it leaves things rather vague. Science rarely is so succinct and simple.
Black Hole material is also "Dark Matter" as it too cannot be directly observed.
Enough effects and gravity of the Black Holes' "Dark Matter" exists on the non-dark observable matter nearby to their hypothesized locations to convince scientists that Black Holes do exist (in addition to the math working out decently).
Stephen Hawking is THE MAN.
For all we know, the mysterious "Dark Matter" could really be just a very dense repository of all of the discarded fruitcakes from around the universe. We don't know.
Scientists have an idea about what "Dark Matter" might be, and likely SOME of that will be correct, but chances are that a majority of it will be wrong. It will actually turn out to be something more complicated than 'matter we just can't observe' so it is now therefore decreed to be henceforth called "Dark Matter".
I believe that atoms once were the smallest particles known, that changed. So will this. It may turn out to just be star ash, but Maybe not.
It could be thousands of things or types of matter, likely even stuff that is NOT dark.
If we can make a B2 bomber into "Dark Matter" from the POV of a man by using it's stealth features and electromagnetic radiation adsorbing coverings, maybe there's just plain ordinary matter out there that is rather cold and covered with some cosmic stealth paint.
The math says it exists and there is enough circumstantial evidence that "something" is there. I doubt it has some mystical properties that make it invisible. There are other dimensions in the universe that mathematics has proven exist, maybe being close or intersecting in some way with matter in those other dimensions is actually causing the "Dark Matter" effect.
I hope to live long enough to see "Dark Matter" become as archaic a term as the body's 4 humors are now from my original analogy.
All this paper shows is that there is a difference between CP violation in the charged B mesons and the neutral B mesons. This is somewhat unexpected and while you cannot rule out something new it is also true that they cannot rule out QCD (strong force) effects.
The problem the strong force is that it is so strong at low energy that our normal technique to calculate what is going on (called perturbation theory) does not work because, rather than small perturbations, the strong interaction causes huge changes. This means that theorists have to make approximations in order to calculate anything and so their results may well just show a flaw in their assumptions rather than a flaw in our understanding of physics.
An excellent example of this was with my grad student experiment which was also measuring CP violation but with kaons. Before our measurement the theorists were saying that there was absolutely no way at all they could have a certain parameter (epsilon'/epsilon) to have a value greater than 1e-3 and it would likely be a lot lower. So, we measured it at around 1.7e-3 and, lo and behold, the theorists adjusted their models and suddenly it was in agreement with theory.
So while this might be an indication of something new I am not yet convinces that it is anything more than an incorrect assumption in a QCD calculation somewhere. Such calculations are fantastically difficult and while in this case there are things that will make it easier, it is not yet convincing evidence.
Actually Newton gets a free pass, one of the two(?) assumptions he wrote down was "time is constant".
And did you exchange a walk on part in the war for a lead role in a cage? - Pink Floyd.
Baryons are hadrons (particles composed by quarks), specifically three quarks, and the proton and neutron are the lightest and most stable of baryons.
The Baryogenesis theory, as proposed by Sakharov, describes a set of three conditions which all had to be met together in order to have a matter-asymetric universe. A baryogenic reaction sets off from a baryon-symmetric state to produce a final state which has a greater content of particles than anti-particles; or, in effect, no anti-particles and a "small" ammount of matter particles (in comparison to the number of annihilation photon "sea" which might be interpreted as the Cosmic Background Radiation). According to Sakharov, a potencially baryogenic reaction has to satisfy all of three conditions:
- It must violate the baryonic number, i.e., the number of baryons in the final state must differ from the initial state. This might seem a trivial requirement, but under the current (very successful) Standard Model of Particle Physics, it is not.
- It must violate CP (charge-parity) symmetry. In other words, the physics of the reaction/decay must be different from its charge-conjugated (and parity-conjugated) counterpart. Specifically, the rate of a baryogenic reaction must differ from the reaction involving the corresponding anti-particles, due to a non-trivial theoretical result known as "CPT theorem".
- It must happen away from equilibrium (thermal and "chemical"). In other words, the reaction rate must be faster than the time it takes for the mixture between initial and final state domain contents to mix and reach equilibrium.
The first two conditions are mostly related to particle physics, and the third is more oriented to cosmology and especially the macroscopic treatment of the universe with (relativistic) thermodynamics. IMHO, the trickiest is to find a decay that satisfies the first condition, since in the Standard Model of Particle Physics this should not happen directly (technically, the baryon number operator does not show up explicitly in the Standard Model Hamiltonian).From what I've gathered, this is the job of looking for a "new" particle whose decay can, not only, satisfy the three Sakharov conditions, but also give the correct predictions. The matter-to-radiation content is fairly precise: it's very small, but not null, about 1 matter particle (think "hydrogen atom") per 10 billion (1010) cosmic background radiation photons. It's one thing to find a particle whose decay satisfies the Sakharov conditions, especially one that violates the baryon number conservation "directly" (i.e., as a "first order" process); it's another thing entirely to justify that that same decay is enough to give that particle-to-photon ratio within an order of magnitude.
My sig is better than your sig.
>> since black holes are made from collapsed stars, they are baryonic.
Although I think the original point that dark matter cannot be attributed to black holes is valid, can baryonic conservation within a black hole really be assumed? If I put 10^40 baryons in a black hole, should I expect to get 10^40 back out via Hawking radiation? What does this say about the information content of a black hole? (I don't know much about these topics, so I'd really like to know.)
Also, to respond to the higgs thing...
If we do just find the Higgs particle from the LHC, and nothing more, then that is pretty much the worst case situation. We know that there are problems with the standard model, but nobody knows for sure what part is wrong, and how it is wrong exactly. Everyone is hoping that the LHC will give results that aren't predicted by the standard model, to give us a better understanding in where and why it is wrong exactly.